summaryrefslogtreecommitdiffstats
path: root/arch/ia64/kernel/perfmon.c
blob: 744329072f33be00a50e616d66bd2a11c3689f93 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
5642
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
5658
5659
5660
5661
5662
5663
5664
5665
5666
5667
5668
5669
5670
5671
5672
5673
5674
5675
5676
5677
5678
5679
5680
5681
5682
5683
5684
5685
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
5709
5710
5711
5712
5713
5714
5715
5716
5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
5740
5741
5742
5743
5744
5745
5746
5747
5748
5749
5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872
5873
5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948
5949
5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
5988
5989
5990
5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479
6480
6481
6482
6483
6484
6485
6486
6487
6488
6489
6490
6491
6492
6493
6494
6495
6496
6497
6498
6499
6500
6501
6502
6503
6504
6505
6506
6507
6508
6509
6510
6511
6512
6513
6514
6515
6516
6517
6518
6519
6520
6521
6522
6523
6524
6525
6526
6527
6528
6529
6530
6531
6532
6533
6534
6535
6536
6537
6538
6539
6540
6541
6542
6543
6544
6545
6546
6547
6548
6549
6550
6551
6552
6553
6554
6555
6556
6557
6558
6559
6560
6561
6562
6563
6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593
6594
6595
6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
6614
6615
6616
6617
6618
6619
6620
6621
6622
6623
6624
6625
6626
6627
6628
6629
6630
6631
6632
6633
6634
6635
6636
6637
6638
6639
6640
6641
6642
6643
6644
6645
6646
6647
6648
6649
6650
6651
6652
6653
6654
6655
6656
6657
6658
6659
6660
6661
6662
6663
6664
6665
6666
6667
6668
6669
6670
6671
6672
6673
6674
6675
6676
6677
6678
6679
6680
6681
6682
6683
6684
6685
6686
6687
6688
6689
6690
6691
6692
6693
6694
6695
6696
6697
6698
6699
6700
6701
6702
6703
6704
6705
6706
6707
6708
6709
6710
6711
6712
6713
6714
6715
6716
6717
6718
6719
6720
6721
6722
6723
6724
6725
6726
6727
6728
6729
6730
6731
6732
6733
6734
6735
6736
6737
6738
6739
6740
6741
6742
6743
6744
6745
6746
6747
6748
6749
6750
6751
6752
6753
6754
6755
6756
6757
6758
6759
6760
6761
6762
6763
6764
6765
6766
6767
6768
6769
6770
6771
6772
6773
6774
6775
6776
6777
6778
6779
6780
6781
6782
6783
6784
6785
6786
6787
6788
6789
6790
6791
6792
6793
6794
6795
6796
6797
6798
6799
6800
6801
6802
6803
6804
6805
6806
6807
6808
6809
6810
6811
6812
6813
6814
6815
6816
6817
6818
6819
6820
6821
6822
6823
6824
6825
6826
6827
6828
6829
6830
6831
6832
6833
6834
6835
6836
6837
/*
 * This file implements the perfmon-2 subsystem which is used
 * to program the IA-64 Performance Monitoring Unit (PMU).
 *
 * The initial version of perfmon.c was written by
 * Ganesh Venkitachalam, IBM Corp.
 *
 * Then it was modified for perfmon-1.x by Stephane Eranian and
 * David Mosberger, Hewlett Packard Co.
 *
 * Version Perfmon-2.x is a rewrite of perfmon-1.x
 * by Stephane Eranian, Hewlett Packard Co.
 *
 * Copyright (C) 1999-2005  Hewlett Packard Co
 *               Stephane Eranian <eranian@hpl.hp.com>
 *               David Mosberger-Tang <davidm@hpl.hp.com>
 *
 * More information about perfmon available at:
 * 	http://www.hpl.hp.com/research/linux/perfmon
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/sysctl.h>
#include <linux/list.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/vfs.h>
#include <linux/smp.h>
#include <linux/pagemap.h>
#include <linux/mount.h>
#include <linux/bitops.h>
#include <linux/capability.h>
#include <linux/rcupdate.h>
#include <linux/completion.h>
#include <linux/tracehook.h>
#include <linux/slab.h>

#include <asm/errno.h>
#include <asm/intrinsics.h>
#include <asm/page.h>
#include <asm/perfmon.h>
#include <asm/processor.h>
#include <asm/signal.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/delay.h>

#ifdef CONFIG_PERFMON
/*
 * perfmon context state
 */
#define PFM_CTX_UNLOADED	1	/* context is not loaded onto any task */
#define PFM_CTX_LOADED		2	/* context is loaded onto a task */
#define PFM_CTX_MASKED		3	/* context is loaded but monitoring is masked due to overflow */
#define PFM_CTX_ZOMBIE		4	/* owner of the context is closing it */

#define PFM_INVALID_ACTIVATION	(~0UL)

#define PFM_NUM_PMC_REGS	64	/* PMC save area for ctxsw */
#define PFM_NUM_PMD_REGS	64	/* PMD save area for ctxsw */

/*
 * depth of message queue
 */
#define PFM_MAX_MSGS		32
#define PFM_CTXQ_EMPTY(g)	((g)->ctx_msgq_head == (g)->ctx_msgq_tail)

/*
 * type of a PMU register (bitmask).
 * bitmask structure:
 * 	bit0   : register implemented
 * 	bit1   : end marker
 * 	bit2-3 : reserved
 * 	bit4   : pmc has pmc.pm
 * 	bit5   : pmc controls a counter (has pmc.oi), pmd is used as counter
 * 	bit6-7 : register type
 * 	bit8-31: reserved
 */
#define PFM_REG_NOTIMPL		0x0 /* not implemented at all */
#define PFM_REG_IMPL		0x1 /* register implemented */
#define PFM_REG_END		0x2 /* end marker */
#define PFM_REG_MONITOR		(0x1<<4|PFM_REG_IMPL) /* a PMC with a pmc.pm field only */
#define PFM_REG_COUNTING	(0x2<<4|PFM_REG_MONITOR) /* a monitor + pmc.oi+ PMD used as a counter */
#define PFM_REG_CONTROL		(0x4<<4|PFM_REG_IMPL) /* PMU control register */
#define	PFM_REG_CONFIG		(0x8<<4|PFM_REG_IMPL) /* configuration register */
#define PFM_REG_BUFFER	 	(0xc<<4|PFM_REG_IMPL) /* PMD used as buffer */

#define PMC_IS_LAST(i)	(pmu_conf->pmc_desc[i].type & PFM_REG_END)
#define PMD_IS_LAST(i)	(pmu_conf->pmd_desc[i].type & PFM_REG_END)

#define PMC_OVFL_NOTIFY(ctx, i)	((ctx)->ctx_pmds[i].flags &  PFM_REGFL_OVFL_NOTIFY)

/* i assumed unsigned */
#define PMC_IS_IMPL(i)	  (i< PMU_MAX_PMCS && (pmu_conf->pmc_desc[i].type & PFM_REG_IMPL))
#define PMD_IS_IMPL(i)	  (i< PMU_MAX_PMDS && (pmu_conf->pmd_desc[i].type & PFM_REG_IMPL))

/* XXX: these assume that register i is implemented */
#define PMD_IS_COUNTING(i) ((pmu_conf->pmd_desc[i].type & PFM_REG_COUNTING) == PFM_REG_COUNTING)
#define PMC_IS_COUNTING(i) ((pmu_conf->pmc_desc[i].type & PFM_REG_COUNTING) == PFM_REG_COUNTING)
#define PMC_IS_MONITOR(i)  ((pmu_conf->pmc_desc[i].type & PFM_REG_MONITOR)  == PFM_REG_MONITOR)
#define PMC_IS_CONTROL(i)  ((pmu_conf->pmc_desc[i].type & PFM_REG_CONTROL)  == PFM_REG_CONTROL)

#define PMC_DFL_VAL(i)     pmu_conf->pmc_desc[i].default_value
#define PMC_RSVD_MASK(i)   pmu_conf->pmc_desc[i].reserved_mask
#define PMD_PMD_DEP(i)	   pmu_conf->pmd_desc[i].dep_pmd[0]
#define PMC_PMD_DEP(i)	   pmu_conf->pmc_desc[i].dep_pmd[0]

#define PFM_NUM_IBRS	  IA64_NUM_DBG_REGS
#define PFM_NUM_DBRS	  IA64_NUM_DBG_REGS

#define CTX_OVFL_NOBLOCK(c)	((c)->ctx_fl_block == 0)
#define CTX_HAS_SMPL(c)		((c)->ctx_fl_is_sampling)
#define PFM_CTX_TASK(h)		(h)->ctx_task

#define PMU_PMC_OI		5 /* position of pmc.oi bit */

/* XXX: does not support more than 64 PMDs */
#define CTX_USED_PMD(ctx, mask) (ctx)->ctx_used_pmds[0] |= (mask)
#define CTX_IS_USED_PMD(ctx, c) (((ctx)->ctx_used_pmds[0] & (1UL << (c))) != 0UL)

#define CTX_USED_MONITOR(ctx, mask) (ctx)->ctx_used_monitors[0] |= (mask)

#define CTX_USED_IBR(ctx,n) 	(ctx)->ctx_used_ibrs[(n)>>6] |= 1UL<< ((n) % 64)
#define CTX_USED_DBR(ctx,n) 	(ctx)->ctx_used_dbrs[(n)>>6] |= 1UL<< ((n) % 64)
#define CTX_USES_DBREGS(ctx)	(((pfm_context_t *)(ctx))->ctx_fl_using_dbreg==1)
#define PFM_CODE_RR	0	/* requesting code range restriction */
#define PFM_DATA_RR	1	/* requestion data range restriction */

#define PFM_CPUINFO_CLEAR(v)	pfm_get_cpu_var(pfm_syst_info) &= ~(v)
#define PFM_CPUINFO_SET(v)	pfm_get_cpu_var(pfm_syst_info) |= (v)
#define PFM_CPUINFO_GET()	pfm_get_cpu_var(pfm_syst_info)

#define RDEP(x)	(1UL<<(x))

/*
 * context protection macros
 * in SMP:
 * 	- we need to protect against CPU concurrency (spin_lock)
 * 	- we need to protect against PMU overflow interrupts (local_irq_disable)
 * in UP:
 * 	- we need to protect against PMU overflow interrupts (local_irq_disable)
 *
 * spin_lock_irqsave()/spin_unlock_irqrestore():
 * 	in SMP: local_irq_disable + spin_lock
 * 	in UP : local_irq_disable
 *
 * spin_lock()/spin_lock():
 * 	in UP : removed automatically
 * 	in SMP: protect against context accesses from other CPU. interrupts
 * 	        are not masked. This is useful for the PMU interrupt handler
 * 	        because we know we will not get PMU concurrency in that code.
 */
#define PROTECT_CTX(c, f) \
	do {  \
		DPRINT(("spinlock_irq_save ctx %p by [%d]\n", c, task_pid_nr(current))); \
		spin_lock_irqsave(&(c)->ctx_lock, f); \
		DPRINT(("spinlocked ctx %p  by [%d]\n", c, task_pid_nr(current))); \
	} while(0)

#define UNPROTECT_CTX(c, f) \
	do { \
		DPRINT(("spinlock_irq_restore ctx %p by [%d]\n", c, task_pid_nr(current))); \
		spin_unlock_irqrestore(&(c)->ctx_lock, f); \
	} while(0)

#define PROTECT_CTX_NOPRINT(c, f) \
	do {  \
		spin_lock_irqsave(&(c)->ctx_lock, f); \
	} while(0)


#define UNPROTECT_CTX_NOPRINT(c, f) \
	do { \
		spin_unlock_irqrestore(&(c)->ctx_lock, f); \
	} while(0)


#define PROTECT_CTX_NOIRQ(c) \
	do {  \
		spin_lock(&(c)->ctx_lock); \
	} while(0)

#define UNPROTECT_CTX_NOIRQ(c) \
	do { \
		spin_unlock(&(c)->ctx_lock); \
	} while(0)


#ifdef CONFIG_SMP

#define GET_ACTIVATION()	pfm_get_cpu_var(pmu_activation_number)
#define INC_ACTIVATION()	pfm_get_cpu_var(pmu_activation_number)++
#define SET_ACTIVATION(c)	(c)->ctx_last_activation = GET_ACTIVATION()

#else /* !CONFIG_SMP */
#define SET_ACTIVATION(t) 	do {} while(0)
#define GET_ACTIVATION(t) 	do {} while(0)
#define INC_ACTIVATION(t) 	do {} while(0)
#endif /* CONFIG_SMP */

#define SET_PMU_OWNER(t, c)	do { pfm_get_cpu_var(pmu_owner) = (t); pfm_get_cpu_var(pmu_ctx) = (c); } while(0)
#define GET_PMU_OWNER()		pfm_get_cpu_var(pmu_owner)
#define GET_PMU_CTX()		pfm_get_cpu_var(pmu_ctx)

#define LOCK_PFS(g)	    	spin_lock_irqsave(&pfm_sessions.pfs_lock, g)
#define UNLOCK_PFS(g)	    	spin_unlock_irqrestore(&pfm_sessions.pfs_lock, g)

#define PFM_REG_RETFLAG_SET(flags, val)	do { flags &= ~PFM_REG_RETFL_MASK; flags |= (val); } while(0)

/*
 * cmp0 must be the value of pmc0
 */
#define PMC0_HAS_OVFL(cmp0)  (cmp0 & ~0x1UL)

#define PFMFS_MAGIC 0xa0b4d889

/*
 * debugging
 */
#define PFM_DEBUGGING 1
#ifdef PFM_DEBUGGING
#define DPRINT(a) \
	do { \
		if (unlikely(pfm_sysctl.debug >0)) { printk("%s.%d: CPU%d [%d] ", __func__, __LINE__, smp_processor_id(), task_pid_nr(current)); printk a; } \
	} while (0)

#define DPRINT_ovfl(a) \
	do { \
		if (unlikely(pfm_sysctl.debug > 0 && pfm_sysctl.debug_ovfl >0)) { printk("%s.%d: CPU%d [%d] ", __func__, __LINE__, smp_processor_id(), task_pid_nr(current)); printk a; } \
	} while (0)
#endif

/*
 * 64-bit software counter structure
 *
 * the next_reset_type is applied to the next call to pfm_reset_regs()
 */
typedef struct {
	unsigned long	val;		/* virtual 64bit counter value */
	unsigned long	lval;		/* last reset value */
	unsigned long	long_reset;	/* reset value on sampling overflow */
	unsigned long	short_reset;    /* reset value on overflow */
	unsigned long	reset_pmds[4];  /* which other pmds to reset when this counter overflows */
	unsigned long	smpl_pmds[4];   /* which pmds are accessed when counter overflow */
	unsigned long	seed;		/* seed for random-number generator */
	unsigned long	mask;		/* mask for random-number generator */
	unsigned int 	flags;		/* notify/do not notify */
	unsigned long	eventid;	/* overflow event identifier */
} pfm_counter_t;

/*
 * context flags
 */
typedef struct {
	unsigned int block:1;		/* when 1, task will blocked on user notifications */
	unsigned int system:1;		/* do system wide monitoring */
	unsigned int using_dbreg:1;	/* using range restrictions (debug registers) */
	unsigned int is_sampling:1;	/* true if using a custom format */
	unsigned int excl_idle:1;	/* exclude idle task in system wide session */
	unsigned int going_zombie:1;	/* context is zombie (MASKED+blocking) */
	unsigned int trap_reason:2;	/* reason for going into pfm_handle_work() */
	unsigned int no_msg:1;		/* no message sent on overflow */
	unsigned int can_restart:1;	/* allowed to issue a PFM_RESTART */
	unsigned int reserved:22;
} pfm_context_flags_t;

#define PFM_TRAP_REASON_NONE		0x0	/* default value */
#define PFM_TRAP_REASON_BLOCK		0x1	/* we need to block on overflow */
#define PFM_TRAP_REASON_RESET		0x2	/* we need to reset PMDs */


/*
 * perfmon context: encapsulates all the state of a monitoring session
 */

typedef struct pfm_context {
	spinlock_t		ctx_lock;		/* context protection */

	pfm_context_flags_t	ctx_flags;		/* bitmask of flags  (block reason incl.) */
	unsigned int		ctx_state;		/* state: active/inactive (no bitfield) */

	struct task_struct 	*ctx_task;		/* task to which context is attached */

	unsigned long		ctx_ovfl_regs[4];	/* which registers overflowed (notification) */

	struct completion	ctx_restart_done;  	/* use for blocking notification mode */

	unsigned long		ctx_used_pmds[4];	/* bitmask of PMD used            */
	unsigned long		ctx_all_pmds[4];	/* bitmask of all accessible PMDs */
	unsigned long		ctx_reload_pmds[4];	/* bitmask of force reload PMD on ctxsw in */

	unsigned long		ctx_all_pmcs[4];	/* bitmask of all accessible PMCs */
	unsigned long		ctx_reload_pmcs[4];	/* bitmask of force reload PMC on ctxsw in */
	unsigned long		ctx_used_monitors[4];	/* bitmask of monitor PMC being used */

	unsigned long		ctx_pmcs[PFM_NUM_PMC_REGS];	/*  saved copies of PMC values */

	unsigned int		ctx_used_ibrs[1];		/* bitmask of used IBR (speedup ctxsw in) */
	unsigned int		ctx_used_dbrs[1];		/* bitmask of used DBR (speedup ctxsw in) */
	unsigned long		ctx_dbrs[IA64_NUM_DBG_REGS];	/* DBR values (cache) when not loaded */
	unsigned long		ctx_ibrs[IA64_NUM_DBG_REGS];	/* IBR values (cache) when not loaded */

	pfm_counter_t		ctx_pmds[PFM_NUM_PMD_REGS]; /* software state for PMDS */

	unsigned long		th_pmcs[PFM_NUM_PMC_REGS];	/* PMC thread save state */
	unsigned long		th_pmds[PFM_NUM_PMD_REGS];	/* PMD thread save state */

	unsigned long		ctx_saved_psr_up;	/* only contains psr.up value */

	unsigned long		ctx_last_activation;	/* context last activation number for last_cpu */
	unsigned int		ctx_last_cpu;		/* CPU id of current or last CPU used (SMP only) */
	unsigned int		ctx_cpu;		/* cpu to which perfmon is applied (system wide) */

	int			ctx_fd;			/* file descriptor used my this context */
	pfm_ovfl_arg_t		ctx_ovfl_arg;		/* argument to custom buffer format handler */

	pfm_buffer_fmt_t	*ctx_buf_fmt;		/* buffer format callbacks */
	void			*ctx_smpl_hdr;		/* points to sampling buffer header kernel vaddr */
	unsigned long		ctx_smpl_size;		/* size of sampling buffer */
	void			*ctx_smpl_vaddr;	/* user level virtual address of smpl buffer */

	wait_queue_head_t 	ctx_msgq_wait;
	pfm_msg_t		ctx_msgq[PFM_MAX_MSGS];
	int			ctx_msgq_head;
	int			ctx_msgq_tail;
	struct fasync_struct	*ctx_async_queue;

	wait_queue_head_t 	ctx_zombieq;		/* termination cleanup wait queue */
} pfm_context_t;

/*
 * magic number used to verify that structure is really
 * a perfmon context
 */
#define PFM_IS_FILE(f)		((f)->f_op == &pfm_file_ops)

#define PFM_GET_CTX(t)	 	((pfm_context_t *)(t)->thread.pfm_context)

#ifdef CONFIG_SMP
#define SET_LAST_CPU(ctx, v)	(ctx)->ctx_last_cpu = (v)
#define GET_LAST_CPU(ctx)	(ctx)->ctx_last_cpu
#else
#define SET_LAST_CPU(ctx, v)	do {} while(0)
#define GET_LAST_CPU(ctx)	do {} while(0)
#endif


#define ctx_fl_block		ctx_flags.block
#define ctx_fl_system		ctx_flags.system
#define ctx_fl_using_dbreg	ctx_flags.using_dbreg
#define ctx_fl_is_sampling	ctx_flags.is_sampling
#define ctx_fl_excl_idle	ctx_flags.excl_idle
#define ctx_fl_going_zombie	ctx_flags.going_zombie
#define ctx_fl_trap_reason	ctx_flags.trap_reason
#define ctx_fl_no_msg		ctx_flags.no_msg
#define ctx_fl_can_restart	ctx_flags.can_restart

#define PFM_SET_WORK_PENDING(t, v)	do { (t)->thread.pfm_needs_checking = v; } while(0);
#define PFM_GET_WORK_PENDING(t)		(t)->thread.pfm_needs_checking

/*
 * global information about all sessions
 * mostly used to synchronize between system wide and per-process
 */
typedef struct {
	spinlock_t		pfs_lock;		   /* lock the structure */

	unsigned int		pfs_task_sessions;	   /* number of per task sessions */
	unsigned int		pfs_sys_sessions;	   /* number of per system wide sessions */
	unsigned int		pfs_sys_use_dbregs;	   /* incremented when a system wide session uses debug regs */
	unsigned int		pfs_ptrace_use_dbregs;	   /* incremented when a process uses debug regs */
	struct task_struct	*pfs_sys_session[NR_CPUS]; /* point to task owning a system-wide session */
} pfm_session_t;

/*
 * information about a PMC or PMD.
 * dep_pmd[]: a bitmask of dependent PMD registers
 * dep_pmc[]: a bitmask of dependent PMC registers
 */
typedef int (*pfm_reg_check_t)(struct task_struct *task, pfm_context_t *ctx, unsigned int cnum, unsigned long *val, struct pt_regs *regs);
typedef struct {
	unsigned int		type;
	int			pm_pos;
	unsigned long		default_value;	/* power-on default value */
	unsigned long		reserved_mask;	/* bitmask of reserved bits */
	pfm_reg_check_t		read_check;
	pfm_reg_check_t		write_check;
	unsigned long		dep_pmd[4];
	unsigned long		dep_pmc[4];
} pfm_reg_desc_t;

/* assume cnum is a valid monitor */
#define PMC_PM(cnum, val)	(((val) >> (pmu_conf->pmc_desc[cnum].pm_pos)) & 0x1)

/*
 * This structure is initialized at boot time and contains
 * a description of the PMU main characteristics.
 *
 * If the probe function is defined, detection is based
 * on its return value: 
 * 	- 0 means recognized PMU
 * 	- anything else means not supported
 * When the probe function is not defined, then the pmu_family field
 * is used and it must match the host CPU family such that:
 * 	- cpu->family & config->pmu_family != 0
 */
typedef struct {
	unsigned long  ovfl_val;	/* overflow value for counters */

	pfm_reg_desc_t *pmc_desc;	/* detailed PMC register dependencies descriptions */
	pfm_reg_desc_t *pmd_desc;	/* detailed PMD register dependencies descriptions */

	unsigned int   num_pmcs;	/* number of PMCS: computed at init time */
	unsigned int   num_pmds;	/* number of PMDS: computed at init time */
	unsigned long  impl_pmcs[4];	/* bitmask of implemented PMCS */
	unsigned long  impl_pmds[4];	/* bitmask of implemented PMDS */

	char	      *pmu_name;	/* PMU family name */
	unsigned int  pmu_family;	/* cpuid family pattern used to identify pmu */
	unsigned int  flags;		/* pmu specific flags */
	unsigned int  num_ibrs;		/* number of IBRS: computed at init time */
	unsigned int  num_dbrs;		/* number of DBRS: computed at init time */
	unsigned int  num_counters;	/* PMC/PMD counting pairs : computed at init time */
	int           (*probe)(void);   /* customized probe routine */
	unsigned int  use_rr_dbregs:1;	/* set if debug registers used for range restriction */
} pmu_config_t;
/*
 * PMU specific flags
 */
#define PFM_PMU_IRQ_RESEND	1	/* PMU needs explicit IRQ resend */

/*
 * debug register related type definitions
 */
typedef struct {
	unsigned long ibr_mask:56;
	unsigned long ibr_plm:4;
	unsigned long ibr_ig:3;
	unsigned long ibr_x:1;
} ibr_mask_reg_t;

typedef struct {
	unsigned long dbr_mask:56;
	unsigned long dbr_plm:4;
	unsigned long dbr_ig:2;
	unsigned long dbr_w:1;
	unsigned long dbr_r:1;
} dbr_mask_reg_t;

typedef union {
	unsigned long  val;
	ibr_mask_reg_t ibr;
	dbr_mask_reg_t dbr;
} dbreg_t;


/*
 * perfmon command descriptions
 */
typedef struct {
	int		(*cmd_func)(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs);
	char		*cmd_name;
	int		cmd_flags;
	unsigned int	cmd_narg;
	size_t		cmd_argsize;
	int		(*cmd_getsize)(void *arg, size_t *sz);
} pfm_cmd_desc_t;

#define PFM_CMD_FD		0x01	/* command requires a file descriptor */
#define PFM_CMD_ARG_READ	0x02	/* command must read argument(s) */
#define PFM_CMD_ARG_RW		0x04	/* command must read/write argument(s) */
#define PFM_CMD_STOP		0x08	/* command does not work on zombie context */


#define PFM_CMD_NAME(cmd)	pfm_cmd_tab[(cmd)].cmd_name
#define PFM_CMD_READ_ARG(cmd)	(pfm_cmd_tab[(cmd)].cmd_flags & PFM_CMD_ARG_READ)
#define PFM_CMD_RW_ARG(cmd)	(pfm_cmd_tab[(cmd)].cmd_flags & PFM_CMD_ARG_RW)
#define PFM_CMD_USE_FD(cmd)	(pfm_cmd_tab[(cmd)].cmd_flags & PFM_CMD_FD)
#define PFM_CMD_STOPPED(cmd)	(pfm_cmd_tab[(cmd)].cmd_flags & PFM_CMD_STOP)

#define PFM_CMD_ARG_MANY	-1 /* cannot be zero */

typedef struct {
	unsigned long pfm_spurious_ovfl_intr_count;	/* keep track of spurious ovfl interrupts */
	unsigned long pfm_replay_ovfl_intr_count;	/* keep track of replayed ovfl interrupts */
	unsigned long pfm_ovfl_intr_count; 		/* keep track of ovfl interrupts */
	unsigned long pfm_ovfl_intr_cycles;		/* cycles spent processing ovfl interrupts */
	unsigned long pfm_ovfl_intr_cycles_min;		/* min cycles spent processing ovfl interrupts */
	unsigned long pfm_ovfl_intr_cycles_max;		/* max cycles spent processing ovfl interrupts */
	unsigned long pfm_smpl_handler_calls;
	unsigned long pfm_smpl_handler_cycles;
	char pad[SMP_CACHE_BYTES] ____cacheline_aligned;
} pfm_stats_t;

/*
 * perfmon internal variables
 */
static pfm_stats_t		pfm_stats[NR_CPUS];
static pfm_session_t		pfm_sessions;	/* global sessions information */

static DEFINE_SPINLOCK(pfm_alt_install_check);
static pfm_intr_handler_desc_t  *pfm_alt_intr_handler;

static struct proc_dir_entry 	*perfmon_dir;
static pfm_uuid_t		pfm_null_uuid = {0,};

static spinlock_t		pfm_buffer_fmt_lock;
static LIST_HEAD(pfm_buffer_fmt_list);

static pmu_config_t		*pmu_conf;

/* sysctl() controls */
pfm_sysctl_t pfm_sysctl;
EXPORT_SYMBOL(pfm_sysctl);

static ctl_table pfm_ctl_table[]={
	{
		.procname	= "debug",
		.data		= &pfm_sysctl.debug,
		.maxlen		= sizeof(int),
		.mode		= 0666,
		.proc_handler	= proc_dointvec,
	},
	{
		.procname	= "debug_ovfl",
		.data		= &pfm_sysctl.debug_ovfl,
		.maxlen		= sizeof(int),
		.mode		= 0666,
		.proc_handler	= proc_dointvec,
	},
	{
		.procname	= "fastctxsw",
		.data		= &pfm_sysctl.fastctxsw,
		.maxlen		= sizeof(int),
		.mode		= 0600,
		.proc_handler	= proc_dointvec,
	},
	{
		.procname	= "expert_mode",
		.data		= &pfm_sysctl.expert_mode,
		.maxlen		= sizeof(int),
		.mode		= 0600,
		.proc_handler	= proc_dointvec,
	},
	{}
};
static ctl_table pfm_sysctl_dir[] = {
	{
		.procname	= "perfmon",
		.mode		= 0555,
		.child		= pfm_ctl_table,
	},
 	{}
};
static ctl_table pfm_sysctl_root[] = {
	{
		.procname	= "kernel",
		.mode		= 0555,
		.child		= pfm_sysctl_dir,
	},
 	{}
};
static struct ctl_table_header *pfm_sysctl_header;

static int pfm_context_unload(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs);

#define pfm_get_cpu_var(v)		__ia64_per_cpu_var(v)
#define pfm_get_cpu_data(a,b)		per_cpu(a, b)

static inline void
pfm_put_task(struct task_struct *task)
{
	if (task != current) put_task_struct(task);
}

static inline void
pfm_reserve_page(unsigned long a)
{
	SetPageReserved(vmalloc_to_page((void *)a));
}
static inline void
pfm_unreserve_page(unsigned long a)
{
	ClearPageReserved(vmalloc_to_page((void*)a));
}

static inline unsigned long
pfm_protect_ctx_ctxsw(pfm_context_t *x)
{
	spin_lock(&(x)->ctx_lock);
	return 0UL;
}

static inline void
pfm_unprotect_ctx_ctxsw(pfm_context_t *x, unsigned long f)
{
	spin_unlock(&(x)->ctx_lock);
}

static inline unsigned int
pfm_do_munmap(struct mm_struct *mm, unsigned long addr, size_t len, int acct)
{
	return do_munmap(mm, addr, len);
}

static inline unsigned long 
pfm_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags, unsigned long exec)
{
	return get_unmapped_area(file, addr, len, pgoff, flags);
}


static int
pfmfs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data,
	     struct vfsmount *mnt)
{
	return get_sb_pseudo(fs_type, "pfm:", NULL, PFMFS_MAGIC, mnt);
}

static struct file_system_type pfm_fs_type = {
	.name     = "pfmfs",
	.get_sb   = pfmfs_get_sb,
	.kill_sb  = kill_anon_super,
};

DEFINE_PER_CPU(unsigned long, pfm_syst_info);
DEFINE_PER_CPU(struct task_struct *, pmu_owner);
DEFINE_PER_CPU(pfm_context_t  *, pmu_ctx);
DEFINE_PER_CPU(unsigned long, pmu_activation_number);
EXPORT_PER_CPU_SYMBOL_GPL(pfm_syst_info);


/* forward declaration */
static const struct file_operations pfm_file_ops;

/*
 * forward declarations
 */
#ifndef CONFIG_SMP
static void pfm_lazy_save_regs (struct task_struct *ta);
#endif

void dump_pmu_state(const char *);
static int pfm_write_ibr_dbr(int mode, pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs);

#include "perfmon_itanium.h"
#include "perfmon_mckinley.h"
#include "perfmon_montecito.h"
#include "perfmon_generic.h"

static pmu_config_t *pmu_confs[]={
	&pmu_conf_mont,
	&pmu_conf_mck,
	&pmu_conf_ita,
	&pmu_conf_gen, /* must be last */
	NULL
};


static int pfm_end_notify_user(pfm_context_t *ctx);

static inline void
pfm_clear_psr_pp(void)
{
	ia64_rsm(IA64_PSR_PP);
	ia64_srlz_i();
}

static inline void
pfm_set_psr_pp(void)
{
	ia64_ssm(IA64_PSR_PP);
	ia64_srlz_i();
}

static inline void
pfm_clear_psr_up(void)
{
	ia64_rsm(IA64_PSR_UP);
	ia64_srlz_i();
}

static inline void
pfm_set_psr_up(void)
{
	ia64_ssm(IA64_PSR_UP);
	ia64_srlz_i();
}

static inline unsigned long
pfm_get_psr(void)
{
	unsigned long tmp;
	tmp = ia64_getreg(_IA64_REG_PSR);
	ia64_srlz_i();
	return tmp;
}

static inline void
pfm_set_psr_l(unsigned long val)
{
	ia64_setreg(_IA64_REG_PSR_L, val);
	ia64_srlz_i();
}

static inline void
pfm_freeze_pmu(void)
{
	ia64_set_pmc(0,1UL);
	ia64_srlz_d();
}

static inline void
pfm_unfreeze_pmu(void)
{
	ia64_set_pmc(0,0UL);
	ia64_srlz_d();
}

static inline void
pfm_restore_ibrs(unsigned long *ibrs, unsigned int nibrs)
{
	int i;

	for (i=0; i < nibrs; i++) {
		ia64_set_ibr(i, ibrs[i]);
		ia64_dv_serialize_instruction();
	}
	ia64_srlz_i();
}

static inline void
pfm_restore_dbrs(unsigned long *dbrs, unsigned int ndbrs)
{
	int i;

	for (i=0; i < ndbrs; i++) {
		ia64_set_dbr(i, dbrs[i]);
		ia64_dv_serialize_data();
	}
	ia64_srlz_d();
}

/*
 * PMD[i] must be a counter. no check is made
 */
static inline unsigned long
pfm_read_soft_counter(pfm_context_t *ctx, int i)
{
	return ctx->ctx_pmds[i].val + (ia64_get_pmd(i) & pmu_conf->ovfl_val);
}

/*
 * PMD[i] must be a counter. no check is made
 */
static inline void
pfm_write_soft_counter(pfm_context_t *ctx, int i, unsigned long val)
{
	unsigned long ovfl_val = pmu_conf->ovfl_val;

	ctx->ctx_pmds[i].val = val  & ~ovfl_val;
	/*
	 * writing to unimplemented part is ignore, so we do not need to
	 * mask off top part
	 */
	ia64_set_pmd(i, val & ovfl_val);
}

static pfm_msg_t *
pfm_get_new_msg(pfm_context_t *ctx)
{
	int idx, next;

	next = (ctx->ctx_msgq_tail+1) % PFM_MAX_MSGS;

	DPRINT(("ctx_fd=%p head=%d tail=%d\n", ctx, ctx->ctx_msgq_head, ctx->ctx_msgq_tail));
	if (next == ctx->ctx_msgq_head) return NULL;

 	idx = 	ctx->ctx_msgq_tail;
	ctx->ctx_msgq_tail = next;

	DPRINT(("ctx=%p head=%d tail=%d msg=%d\n", ctx, ctx->ctx_msgq_head, ctx->ctx_msgq_tail, idx));

	return ctx->ctx_msgq+idx;
}

static pfm_msg_t *
pfm_get_next_msg(pfm_context_t *ctx)
{
	pfm_msg_t *msg;

	DPRINT(("ctx=%p head=%d tail=%d\n", ctx, ctx->ctx_msgq_head, ctx->ctx_msgq_tail));

	if (PFM_CTXQ_EMPTY(ctx)) return NULL;

	/*
	 * get oldest message
	 */
	msg = ctx->ctx_msgq+ctx->ctx_msgq_head;

	/*
	 * and move forward
	 */
	ctx->ctx_msgq_head = (ctx->ctx_msgq_head+1) % PFM_MAX_MSGS;

	DPRINT(("ctx=%p head=%d tail=%d type=%d\n", ctx, ctx->ctx_msgq_head, ctx->ctx_msgq_tail, msg->pfm_gen_msg.msg_type));

	return msg;
}

static void
pfm_reset_msgq(pfm_context_t *ctx)
{
	ctx->ctx_msgq_head = ctx->ctx_msgq_tail = 0;
	DPRINT(("ctx=%p msgq reset\n", ctx));
}

static void *
pfm_rvmalloc(unsigned long size)
{
	void *mem;
	unsigned long addr;

	size = PAGE_ALIGN(size);
	mem  = vmalloc(size);
	if (mem) {
		//printk("perfmon: CPU%d pfm_rvmalloc(%ld)=%p\n", smp_processor_id(), size, mem);
		memset(mem, 0, size);
		addr = (unsigned long)mem;
		while (size > 0) {
			pfm_reserve_page(addr);
			addr+=PAGE_SIZE;
			size-=PAGE_SIZE;
		}
	}
	return mem;
}

static void
pfm_rvfree(void *mem, unsigned long size)
{
	unsigned long addr;

	if (mem) {
		DPRINT(("freeing physical buffer @%p size=%lu\n", mem, size));
		addr = (unsigned long) mem;
		while ((long) size > 0) {
			pfm_unreserve_page(addr);
			addr+=PAGE_SIZE;
			size-=PAGE_SIZE;
		}
		vfree(mem);
	}
	return;
}

static pfm_context_t *
pfm_context_alloc(int ctx_flags)
{
	pfm_context_t *ctx;

	/* 
	 * allocate context descriptor 
	 * must be able to free with interrupts disabled
	 */
	ctx = kzalloc(sizeof(pfm_context_t), GFP_KERNEL);
	if (ctx) {
		DPRINT(("alloc ctx @%p\n", ctx));

		/*
		 * init context protection lock
		 */
		spin_lock_init(&ctx->ctx_lock);

		/*
		 * context is unloaded
		 */
		ctx->ctx_state = PFM_CTX_UNLOADED;

		/*
		 * initialization of context's flags
		 */
		ctx->ctx_fl_block       = (ctx_flags & PFM_FL_NOTIFY_BLOCK) ? 1 : 0;
		ctx->ctx_fl_system      = (ctx_flags & PFM_FL_SYSTEM_WIDE) ? 1: 0;
		ctx->ctx_fl_no_msg      = (ctx_flags & PFM_FL_OVFL_NO_MSG) ? 1: 0;
		/*
		 * will move to set properties
		 * ctx->ctx_fl_excl_idle   = (ctx_flags & PFM_FL_EXCL_IDLE) ? 1: 0;
		 */

		/*
		 * init restart semaphore to locked
		 */
		init_completion(&ctx->ctx_restart_done);

		/*
		 * activation is used in SMP only
		 */
		ctx->ctx_last_activation = PFM_INVALID_ACTIVATION;
		SET_LAST_CPU(ctx, -1);

		/*
		 * initialize notification message queue
		 */
		ctx->ctx_msgq_head = ctx->ctx_msgq_tail = 0;
		init_waitqueue_head(&ctx->ctx_msgq_wait);
		init_waitqueue_head(&ctx->ctx_zombieq);

	}
	return ctx;
}

static void
pfm_context_free(pfm_context_t *ctx)
{
	if (ctx) {
		DPRINT(("free ctx @%p\n", ctx));
		kfree(ctx);
	}
}

static void
pfm_mask_monitoring(struct task_struct *task)
{
	pfm_context_t *ctx = PFM_GET_CTX(task);
	unsigned long mask, val, ovfl_mask;
	int i;

	DPRINT_ovfl(("masking monitoring for [%d]\n", task_pid_nr(task)));

	ovfl_mask = pmu_conf->ovfl_val;
	/*
	 * monitoring can only be masked as a result of a valid
	 * counter overflow. In UP, it means that the PMU still
	 * has an owner. Note that the owner can be different
	 * from the current task. However the PMU state belongs
	 * to the owner.
	 * In SMP, a valid overflow only happens when task is
	 * current. Therefore if we come here, we know that
	 * the PMU state belongs to the current task, therefore
	 * we can access the live registers.
	 *
	 * So in both cases, the live register contains the owner's
	 * state. We can ONLY touch the PMU registers and NOT the PSR.
	 *
	 * As a consequence to this call, the ctx->th_pmds[] array
	 * contains stale information which must be ignored
	 * when context is reloaded AND monitoring is active (see
	 * pfm_restart).
	 */
	mask = ctx->ctx_used_pmds[0];
	for (i = 0; mask; i++, mask>>=1) {
		/* skip non used pmds */
		if ((mask & 0x1) == 0) continue;
		val = ia64_get_pmd(i);

		if (PMD_IS_COUNTING(i)) {
			/*
		 	 * we rebuild the full 64 bit value of the counter
		 	 */
			ctx->ctx_pmds[i].val += (val & ovfl_mask);
		} else {
			ctx->ctx_pmds[i].val = val;
		}
		DPRINT_ovfl(("pmd[%d]=0x%lx hw_pmd=0x%lx\n",
			i,
			ctx->ctx_pmds[i].val,
			val & ovfl_mask));
	}
	/*
	 * mask monitoring by setting the privilege level to 0
	 * we cannot use psr.pp/psr.up for this, it is controlled by
	 * the user
	 *
	 * if task is current, modify actual registers, otherwise modify
	 * thread save state, i.e., what will be restored in pfm_load_regs()
	 */
	mask = ctx->ctx_used_monitors[0] >> PMU_FIRST_COUNTER;
	for(i= PMU_FIRST_COUNTER; mask; i++, mask>>=1) {
		if ((mask & 0x1) == 0UL) continue;
		ia64_set_pmc(i, ctx->th_pmcs[i] & ~0xfUL);
		ctx->th_pmcs[i] &= ~0xfUL;
		DPRINT_ovfl(("pmc[%d]=0x%lx\n", i, ctx->th_pmcs[i]));
	}
	/*
	 * make all of this visible
	 */
	ia64_srlz_d();
}

/*
 * must always be done with task == current
 *
 * context must be in MASKED state when calling
 */
static void
pfm_restore_monitoring(struct task_struct *task)
{
	pfm_context_t *ctx = PFM_GET_CTX(task);
	unsigned long mask, ovfl_mask;
	unsigned long psr, val;
	int i, is_system;

	is_system = ctx->ctx_fl_system;
	ovfl_mask = pmu_conf->ovfl_val;

	if (task != current) {
		printk(KERN_ERR "perfmon.%d: invalid task[%d] current[%d]\n", __LINE__, task_pid_nr(task), task_pid_nr(current));
		return;
	}
	if (ctx->ctx_state != PFM_CTX_MASKED) {
		printk(KERN_ERR "perfmon.%d: task[%d] current[%d] invalid state=%d\n", __LINE__,
			task_pid_nr(task), task_pid_nr(current), ctx->ctx_state);
		return;
	}
	psr = pfm_get_psr();
	/*
	 * monitoring is masked via the PMC.
	 * As we restore their value, we do not want each counter to
	 * restart right away. We stop monitoring using the PSR,
	 * restore the PMC (and PMD) and then re-establish the psr
	 * as it was. Note that there can be no pending overflow at
	 * this point, because monitoring was MASKED.
	 *
	 * system-wide session are pinned and self-monitoring
	 */
	if (is_system && (PFM_CPUINFO_GET() & PFM_CPUINFO_DCR_PP)) {
		/* disable dcr pp */
		ia64_setreg(_IA64_REG_CR_DCR, ia64_getreg(_IA64_REG_CR_DCR) & ~IA64_DCR_PP);
		pfm_clear_psr_pp();
	} else {
		pfm_clear_psr_up();
	}
	/*
	 * first, we restore the PMD
	 */
	mask = ctx->ctx_used_pmds[0];
	for (i = 0; mask; i++, mask>>=1) {
		/* skip non used pmds */
		if ((mask & 0x1) == 0) continue;

		if (PMD_IS_COUNTING(i)) {
			/*
			 * we split the 64bit value according to
			 * counter width
			 */
			val = ctx->ctx_pmds[i].val & ovfl_mask;
			ctx->ctx_pmds[i].val &= ~ovfl_mask;
		} else {
			val = ctx->ctx_pmds[i].val;
		}
		ia64_set_pmd(i, val);

		DPRINT(("pmd[%d]=0x%lx hw_pmd=0x%lx\n",
			i,
			ctx->ctx_pmds[i].val,
			val));
	}
	/*
	 * restore the PMCs
	 */
	mask = ctx->ctx_used_monitors[0] >> PMU_FIRST_COUNTER;
	for(i= PMU_FIRST_COUNTER; mask; i++, mask>>=1) {
		if ((mask & 0x1) == 0UL) continue;
		ctx->th_pmcs[i] = ctx->ctx_pmcs[i];
		ia64_set_pmc(i, ctx->th_pmcs[i]);
		DPRINT(("[%d] pmc[%d]=0x%lx\n",
					task_pid_nr(task), i, ctx->th_pmcs[i]));
	}
	ia64_srlz_d();

	/*
	 * must restore DBR/IBR because could be modified while masked
	 * XXX: need to optimize 
	 */
	if (ctx->ctx_fl_using_dbreg) {
		pfm_restore_ibrs(ctx->ctx_ibrs, pmu_conf->num_ibrs);
		pfm_restore_dbrs(ctx->ctx_dbrs, pmu_conf->num_dbrs);
	}

	/*
	 * now restore PSR
	 */
	if (is_system && (PFM_CPUINFO_GET() & PFM_CPUINFO_DCR_PP)) {
		/* enable dcr pp */
		ia64_setreg(_IA64_REG_CR_DCR, ia64_getreg(_IA64_REG_CR_DCR) | IA64_DCR_PP);
		ia64_srlz_i();
	}
	pfm_set_psr_l(psr);
}

static inline void
pfm_save_pmds(unsigned long *pmds, unsigned long mask)
{
	int i;

	ia64_srlz_d();

	for (i=0; mask; i++, mask>>=1) {
		if (mask & 0x1) pmds[i] = ia64_get_pmd(i);
	}
}

/*
 * reload from thread state (used for ctxw only)
 */
static inline void
pfm_restore_pmds(unsigned long *pmds, unsigned long mask)
{
	int i;
	unsigned long val, ovfl_val = pmu_conf->ovfl_val;

	for (i=0; mask; i++, mask>>=1) {
		if ((mask & 0x1) == 0) continue;
		val = PMD_IS_COUNTING(i) ? pmds[i] & ovfl_val : pmds[i];
		ia64_set_pmd(i, val);
	}
	ia64_srlz_d();
}

/*
 * propagate PMD from context to thread-state
 */
static inline void
pfm_copy_pmds(struct task_struct *task, pfm_context_t *ctx)
{
	unsigned long ovfl_val = pmu_conf->ovfl_val;
	unsigned long mask = ctx->ctx_all_pmds[0];
	unsigned long val;
	int i;

	DPRINT(("mask=0x%lx\n", mask));

	for (i=0; mask; i++, mask>>=1) {

		val = ctx->ctx_pmds[i].val;

		/*
		 * We break up the 64 bit value into 2 pieces
		 * the lower bits go to the machine state in the
		 * thread (will be reloaded on ctxsw in).
		 * The upper part stays in the soft-counter.
		 */
		if (PMD_IS_COUNTING(i)) {
			ctx->ctx_pmds[i].val = val & ~ovfl_val;
			 val &= ovfl_val;
		}
		ctx->th_pmds[i] = val;

		DPRINT(("pmd[%d]=0x%lx soft_val=0x%lx\n",
			i,
			ctx->th_pmds[i],
			ctx->ctx_pmds[i].val));
	}
}

/*
 * propagate PMC from context to thread-state
 */
static inline void
pfm_copy_pmcs(struct task_struct *task, pfm_context_t *ctx)
{
	unsigned long mask = ctx->ctx_all_pmcs[0];
	int i;

	DPRINT(("mask=0x%lx\n", mask));

	for (i=0; mask; i++, mask>>=1) {
		/* masking 0 with ovfl_val yields 0 */
		ctx->th_pmcs[i] = ctx->ctx_pmcs[i];
		DPRINT(("pmc[%d]=0x%lx\n", i, ctx->th_pmcs[i]));
	}
}



static inline void
pfm_restore_pmcs(unsigned long *pmcs, unsigned long mask)
{
	int i;

	for (i=0; mask; i++, mask>>=1) {
		if ((mask & 0x1) == 0) continue;
		ia64_set_pmc(i, pmcs[i]);
	}
	ia64_srlz_d();
}

static inline int
pfm_uuid_cmp(pfm_uuid_t a, pfm_uuid_t b)
{
	return memcmp(a, b, sizeof(pfm_uuid_t));
}

static inline int
pfm_buf_fmt_exit(pfm_buffer_fmt_t *fmt, struct task_struct *task, void *buf, struct pt_regs *regs)
{
	int ret = 0;
	if (fmt->fmt_exit) ret = (*fmt->fmt_exit)(task, buf, regs);
	return ret;
}

static inline int
pfm_buf_fmt_getsize(pfm_buffer_fmt_t *fmt, struct task_struct *task, unsigned int flags, int cpu, void *arg, unsigned long *size)
{
	int ret = 0;
	if (fmt->fmt_getsize) ret = (*fmt->fmt_getsize)(task, flags, cpu, arg, size);
	return ret;
}


static inline int
pfm_buf_fmt_validate(pfm_buffer_fmt_t *fmt, struct task_struct *task, unsigned int flags,
		     int cpu, void *arg)
{
	int ret = 0;
	if (fmt->fmt_validate) ret = (*fmt->fmt_validate)(task, flags, cpu, arg);
	return ret;
}

static inline int
pfm_buf_fmt_init(pfm_buffer_fmt_t *fmt, struct task_struct *task, void *buf, unsigned int flags,
		     int cpu, void *arg)
{
	int ret = 0;
	if (fmt->fmt_init) ret = (*fmt->fmt_init)(task, buf, flags, cpu, arg);
	return ret;
}

static inline int
pfm_buf_fmt_restart(pfm_buffer_fmt_t *fmt, struct task_struct *task, pfm_ovfl_ctrl_t *ctrl, void *buf, struct pt_regs *regs)
{
	int ret = 0;
	if (fmt->fmt_restart) ret = (*fmt->fmt_restart)(task, ctrl, buf, regs);
	return ret;
}

static inline int
pfm_buf_fmt_restart_active(pfm_buffer_fmt_t *fmt, struct task_struct *task, pfm_ovfl_ctrl_t *ctrl, void *buf, struct pt_regs *regs)
{
	int ret = 0;
	if (fmt->fmt_restart_active) ret = (*fmt->fmt_restart_active)(task, ctrl, buf, regs);
	return ret;
}

static pfm_buffer_fmt_t *
__pfm_find_buffer_fmt(pfm_uuid_t uuid)
{
	struct list_head * pos;
	pfm_buffer_fmt_t * entry;

	list_for_each(pos, &pfm_buffer_fmt_list) {
		entry = list_entry(pos, pfm_buffer_fmt_t, fmt_list);
		if (pfm_uuid_cmp(uuid, entry->fmt_uuid) == 0)
			return entry;
	}
	return NULL;
}
 
/*
 * find a buffer format based on its uuid
 */
static pfm_buffer_fmt_t *
pfm_find_buffer_fmt(pfm_uuid_t uuid)
{
	pfm_buffer_fmt_t * fmt;
	spin_lock(&pfm_buffer_fmt_lock);
	fmt = __pfm_find_buffer_fmt(uuid);
	spin_unlock(&pfm_buffer_fmt_lock);
	return fmt;
}
 
int
pfm_register_buffer_fmt(pfm_buffer_fmt_t *fmt)
{
	int ret = 0;

	/* some sanity checks */
	if (fmt == NULL || fmt->fmt_name == NULL) return -EINVAL;

	/* we need at least a handler */
	if (fmt->fmt_handler == NULL) return -EINVAL;

	/*
	 * XXX: need check validity of fmt_arg_size
	 */

	spin_lock(&pfm_buffer_fmt_lock);

	if (__pfm_find_buffer_fmt(fmt->fmt_uuid)) {
		printk(KERN_ERR "perfmon: duplicate sampling format: %s\n", fmt->fmt_name);
		ret = -EBUSY;
		goto out;
	} 
	list_add(&fmt->fmt_list, &pfm_buffer_fmt_list);
	printk(KERN_INFO "perfmon: added sampling format %s\n", fmt->fmt_name);

out:
	spin_unlock(&pfm_buffer_fmt_lock);
 	return ret;
}
EXPORT_SYMBOL(pfm_register_buffer_fmt);

int
pfm_unregister_buffer_fmt(pfm_uuid_t uuid)
{
	pfm_buffer_fmt_t *fmt;
	int ret = 0;

	spin_lock(&pfm_buffer_fmt_lock);

	fmt = __pfm_find_buffer_fmt(uuid);
	if (!fmt) {
		printk(KERN_ERR "perfmon: cannot unregister format, not found\n");
		ret = -EINVAL;
		goto out;
	}
	list_del_init(&fmt->fmt_list);
	printk(KERN_INFO "perfmon: removed sampling format: %s\n", fmt->fmt_name);

out:
	spin_unlock(&pfm_buffer_fmt_lock);
	return ret;

}
EXPORT_SYMBOL(pfm_unregister_buffer_fmt);

extern void update_pal_halt_status(int);

static int
pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
{
	unsigned long flags;
	/*
	 * validity checks on cpu_mask have been done upstream
	 */
	LOCK_PFS(flags);

	DPRINT(("in sys_sessions=%u task_sessions=%u dbregs=%u syswide=%d cpu=%u\n",
		pfm_sessions.pfs_sys_sessions,
		pfm_sessions.pfs_task_sessions,
		pfm_sessions.pfs_sys_use_dbregs,
		is_syswide,
		cpu));

	if (is_syswide) {
		/*
		 * cannot mix system wide and per-task sessions
		 */
		if (pfm_sessions.pfs_task_sessions > 0UL) {
			DPRINT(("system wide not possible, %u conflicting task_sessions\n",
			  	pfm_sessions.pfs_task_sessions));
			goto abort;
		}

		if (pfm_sessions.pfs_sys_session[cpu]) goto error_conflict;

		DPRINT(("reserving system wide session on CPU%u currently on CPU%u\n", cpu, smp_processor_id()));

		pfm_sessions.pfs_sys_session[cpu] = task;

		pfm_sessions.pfs_sys_sessions++ ;

	} else {
		if (pfm_sessions.pfs_sys_sessions) goto abort;
		pfm_sessions.pfs_task_sessions++;
	}

	DPRINT(("out sys_sessions=%u task_sessions=%u dbregs=%u syswide=%d cpu=%u\n",
		pfm_sessions.pfs_sys_sessions,
		pfm_sessions.pfs_task_sessions,
		pfm_sessions.pfs_sys_use_dbregs,
		is_syswide,
		cpu));

	/*
	 * disable default_idle() to go to PAL_HALT
	 */
	update_pal_halt_status(0);

	UNLOCK_PFS(flags);

	return 0;

error_conflict:
	DPRINT(("system wide not possible, conflicting session [%d] on CPU%d\n",
  		task_pid_nr(pfm_sessions.pfs_sys_session[cpu]),
		cpu));
abort:
	UNLOCK_PFS(flags);

	return -EBUSY;

}

static int
pfm_unreserve_session(pfm_context_t *ctx, int is_syswide, unsigned int cpu)
{
	unsigned long flags;
	/*
	 * validity checks on cpu_mask have been done upstream
	 */
	LOCK_PFS(flags);

	DPRINT(("in sys_sessions=%u task_sessions=%u dbregs=%u syswide=%d cpu=%u\n",
		pfm_sessions.pfs_sys_sessions,
		pfm_sessions.pfs_task_sessions,
		pfm_sessions.pfs_sys_use_dbregs,
		is_syswide,
		cpu));


	if (is_syswide) {
		pfm_sessions.pfs_sys_session[cpu] = NULL;
		/*
		 * would not work with perfmon+more than one bit in cpu_mask
		 */
		if (ctx && ctx->ctx_fl_using_dbreg) {
			if (pfm_sessions.pfs_sys_use_dbregs == 0) {
				printk(KERN_ERR "perfmon: invalid release for ctx %p sys_use_dbregs=0\n", ctx);
			} else {
				pfm_sessions.pfs_sys_use_dbregs--;
			}
		}
		pfm_sessions.pfs_sys_sessions--;
	} else {
		pfm_sessions.pfs_task_sessions--;
	}
	DPRINT(("out sys_sessions=%u task_sessions=%u dbregs=%u syswide=%d cpu=%u\n",
		pfm_sessions.pfs_sys_sessions,
		pfm_sessions.pfs_task_sessions,
		pfm_sessions.pfs_sys_use_dbregs,
		is_syswide,
		cpu));

	/*
	 * if possible, enable default_idle() to go into PAL_HALT
	 */
	if (pfm_sessions.pfs_task_sessions == 0 && pfm_sessions.pfs_sys_sessions == 0)
		update_pal_halt_status(1);

	UNLOCK_PFS(flags);

	return 0;
}

/*
 * removes virtual mapping of the sampling buffer.
 * IMPORTANT: cannot be called with interrupts disable, e.g. inside
 * a PROTECT_CTX() section.
 */
static int
pfm_remove_smpl_mapping(struct task_struct *task, void *vaddr, unsigned long size)
{
	int r;

	/* sanity checks */
	if (task->mm == NULL || size == 0UL || vaddr == NULL) {
		printk(KERN_ERR "perfmon: pfm_remove_smpl_mapping [%d] invalid context mm=%p\n", task_pid_nr(task), task->mm);
		return -EINVAL;
	}

	DPRINT(("smpl_vaddr=%p size=%lu\n", vaddr, size));

	/*
	 * does the actual unmapping
	 */
	down_write(&task->mm->mmap_sem);

	DPRINT(("down_write done smpl_vaddr=%p size=%lu\n", vaddr, size));

	r = pfm_do_munmap(task->mm, (unsigned long)vaddr, size, 0);

	up_write(&task->mm->mmap_sem);
	if (r !=0) {
		printk(KERN_ERR "perfmon: [%d] unable to unmap sampling buffer @%p size=%lu\n", task_pid_nr(task), vaddr, size);
	}

	DPRINT(("do_unmap(%p, %lu)=%d\n", vaddr, size, r));

	return 0;
}

/*
 * free actual physical storage used by sampling buffer
 */
#if 0
static int
pfm_free_smpl_buffer(pfm_context_t *ctx)
{
	pfm_buffer_fmt_t *fmt;

	if (ctx->ctx_smpl_hdr == NULL) goto invalid_free;

	/*
	 * we won't use the buffer format anymore
	 */
	fmt = ctx->ctx_buf_fmt;

	DPRINT(("sampling buffer @%p size %lu vaddr=%p\n",
		ctx->ctx_smpl_hdr,
		ctx->ctx_smpl_size,
		ctx->ctx_smpl_vaddr));

	pfm_buf_fmt_exit(fmt, current, NULL, NULL);

	/*
	 * free the buffer
	 */
	pfm_rvfree(ctx->ctx_smpl_hdr, ctx->ctx_smpl_size);

	ctx->ctx_smpl_hdr  = NULL;
	ctx->ctx_smpl_size = 0UL;

	return 0;

invalid_free:
	printk(KERN_ERR "perfmon: pfm_free_smpl_buffer [%d] no buffer\n", task_pid_nr(current));
	return -EINVAL;
}
#endif

static inline void
pfm_exit_smpl_buffer(pfm_buffer_fmt_t *fmt)
{
	if (fmt == NULL) return;

	pfm_buf_fmt_exit(fmt, current, NULL, NULL);

}

/*
 * pfmfs should _never_ be mounted by userland - too much of security hassle,
 * no real gain from having the whole whorehouse mounted. So we don't need
 * any operations on the root directory. However, we need a non-trivial
 * d_name - pfm: will go nicely and kill the special-casing in procfs.
 */
static struct vfsmount *pfmfs_mnt;

static int __init
init_pfm_fs(void)
{
	int err = register_filesystem(&pfm_fs_type);
	if (!err) {
		pfmfs_mnt = kern_mount(&pfm_fs_type);
		err = PTR_ERR(pfmfs_mnt);
		if (IS_ERR(pfmfs_mnt))
			unregister_filesystem(&pfm_fs_type);
		else
			err = 0;
	}
	return err;
}

static ssize_t
pfm_read(struct file *filp, char __user *buf, size_t size, loff_t *ppos)
{
	pfm_context_t *ctx;
	pfm_msg_t *msg;
	ssize_t ret;
	unsigned long flags;
  	DECLARE_WAITQUEUE(wait, current);
	if (PFM_IS_FILE(filp) == 0) {
		printk(KERN_ERR "perfmon: pfm_poll: bad magic [%d]\n", task_pid_nr(current));
		return -EINVAL;
	}

	ctx = (pfm_context_t *)filp->private_data;
	if (ctx == NULL) {
		printk(KERN_ERR "perfmon: pfm_read: NULL ctx [%d]\n", task_pid_nr(current));
		return -EINVAL;
	}

	/*
	 * check even when there is no message
	 */
	if (size < sizeof(pfm_msg_t)) {
		DPRINT(("message is too small ctx=%p (>=%ld)\n", ctx, sizeof(pfm_msg_t)));
		return -EINVAL;
	}

	PROTECT_CTX(ctx, flags);

  	/*
	 * put ourselves on the wait queue
	 */
  	add_wait_queue(&ctx->ctx_msgq_wait, &wait);


  	for(;;) {
		/*
		 * check wait queue
		 */

  		set_current_state(TASK_INTERRUPTIBLE);

		DPRINT(("head=%d tail=%d\n", ctx->ctx_msgq_head, ctx->ctx_msgq_tail));

		ret = 0;
		if(PFM_CTXQ_EMPTY(ctx) == 0) break;

		UNPROTECT_CTX(ctx, flags);

		/*
		 * check non-blocking read
		 */
      		ret = -EAGAIN;
		if(filp->f_flags & O_NONBLOCK) break;

		/*
		 * check pending signals
		 */
		if(signal_pending(current)) {
			ret = -EINTR;
			break;
		}
      		/*
		 * no message, so wait
		 */
      		schedule();

		PROTECT_CTX(ctx, flags);
	}
	DPRINT(("[%d] back to running ret=%ld\n", task_pid_nr(current), ret));
  	set_current_state(TASK_RUNNING);
	remove_wait_queue(&ctx->ctx_msgq_wait, &wait);

	if (ret < 0) goto abort;

	ret = -EINVAL;
	msg = pfm_get_next_msg(ctx);
	if (msg == NULL) {
		printk(KERN_ERR "perfmon: pfm_read no msg for ctx=%p [%d]\n", ctx, task_pid_nr(current));
		goto abort_locked;
	}

	DPRINT(("fd=%d type=%d\n", msg->pfm_gen_msg.msg_ctx_fd, msg->pfm_gen_msg.msg_type));

	ret = -EFAULT;
  	if(copy_to_user(buf, msg, sizeof(pfm_msg_t)) == 0) ret = sizeof(pfm_msg_t);

abort_locked:
	UNPROTECT_CTX(ctx, flags);
abort:
	return ret;
}

static ssize_t
pfm_write(struct file *file, const char __user *ubuf,
			  size_t size, loff_t *ppos)
{
	DPRINT(("pfm_write called\n"));
	return -EINVAL;
}

static unsigned int
pfm_poll(struct file *filp, poll_table * wait)
{
	pfm_context_t *ctx;
	unsigned long flags;
	unsigned int mask = 0;

	if (PFM_IS_FILE(filp) == 0) {
		printk(KERN_ERR "perfmon: pfm_poll: bad magic [%d]\n", task_pid_nr(current));
		return 0;
	}

	ctx = (pfm_context_t *)filp->private_data;
	if (ctx == NULL) {
		printk(KERN_ERR "perfmon: pfm_poll: NULL ctx [%d]\n", task_pid_nr(current));
		return 0;
	}


	DPRINT(("pfm_poll ctx_fd=%d before poll_wait\n", ctx->ctx_fd));

	poll_wait(filp, &ctx->ctx_msgq_wait, wait);

	PROTECT_CTX(ctx, flags);

	if (PFM_CTXQ_EMPTY(ctx) == 0)
		mask =  POLLIN | POLLRDNORM;

	UNPROTECT_CTX(ctx, flags);

	DPRINT(("pfm_poll ctx_fd=%d mask=0x%x\n", ctx->ctx_fd, mask));

	return mask;
}

static long
pfm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	DPRINT(("pfm_ioctl called\n"));
	return -EINVAL;
}

/*
 * interrupt cannot be masked when coming here
 */
static inline int
pfm_do_fasync(int fd, struct file *filp, pfm_context_t *ctx, int on)
{
	int ret;

	ret = fasync_helper (fd, filp, on, &ctx->ctx_async_queue);

	DPRINT(("pfm_fasync called by [%d] on ctx_fd=%d on=%d async_queue=%p ret=%d\n",
		task_pid_nr(current),
		fd,
		on,
		ctx->ctx_async_queue, ret));

	return ret;
}

static int
pfm_fasync(int fd, struct file *filp, int on)
{
	pfm_context_t *ctx;
	int ret;

	if (PFM_IS_FILE(filp) == 0) {
		printk(KERN_ERR "perfmon: pfm_fasync bad magic [%d]\n", task_pid_nr(current));
		return -EBADF;
	}

	ctx = (pfm_context_t *)filp->private_data;
	if (ctx == NULL) {
		printk(KERN_ERR "perfmon: pfm_fasync NULL ctx [%d]\n", task_pid_nr(current));
		return -EBADF;
	}
	/*
	 * we cannot mask interrupts during this call because this may
	 * may go to sleep if memory is not readily avalaible.
	 *
	 * We are protected from the conetxt disappearing by the get_fd()/put_fd()
	 * done in caller. Serialization of this function is ensured by caller.
	 */
	ret = pfm_do_fasync(fd, filp, ctx, on);


	DPRINT(("pfm_fasync called on ctx_fd=%d on=%d async_queue=%p ret=%d\n",
		fd,
		on,
		ctx->ctx_async_queue, ret));

	return ret;
}

#ifdef CONFIG_SMP
/*
 * this function is exclusively called from pfm_close().
 * The context is not protected at that time, nor are interrupts
 * on the remote CPU. That's necessary to avoid deadlocks.
 */
static void
pfm_syswide_force_stop(void *info)
{
	pfm_context_t   *ctx = (pfm_context_t *)info;
	struct pt_regs *regs = task_pt_regs(current);
	struct task_struct *owner;
	unsigned long flags;
	int ret;

	if (ctx->ctx_cpu != smp_processor_id()) {
		printk(KERN_ERR "perfmon: pfm_syswide_force_stop for CPU%d  but on CPU%d\n",
			ctx->ctx_cpu,
			smp_processor_id());
		return;
	}
	owner = GET_PMU_OWNER();
	if (owner != ctx->ctx_task) {
		printk(KERN_ERR "perfmon: pfm_syswide_force_stop CPU%d unexpected owner [%d] instead of [%d]\n",
			smp_processor_id(),
			task_pid_nr(owner), task_pid_nr(ctx->ctx_task));
		return;
	}
	if (GET_PMU_CTX() != ctx) {
		printk(KERN_ERR "perfmon: pfm_syswide_force_stop CPU%d unexpected ctx %p instead of %p\n",
			smp_processor_id(),
			GET_PMU_CTX(), ctx);
		return;
	}

	DPRINT(("on CPU%d forcing system wide stop for [%d]\n", smp_processor_id(), task_pid_nr(ctx->ctx_task)));
	/*
	 * the context is already protected in pfm_close(), we simply
	 * need to mask interrupts to avoid a PMU interrupt race on
	 * this CPU
	 */
	local_irq_save(flags);

	ret = pfm_context_unload(ctx, NULL, 0, regs);
	if (ret) {
		DPRINT(("context_unload returned %d\n", ret));
	}

	/*
	 * unmask interrupts, PMU interrupts are now spurious here
	 */
	local_irq_restore(flags);
}

static void
pfm_syswide_cleanup_other_cpu(pfm_context_t *ctx)
{
	int ret;

	DPRINT(("calling CPU%d for cleanup\n", ctx->ctx_cpu));
	ret = smp_call_function_single(ctx->ctx_cpu, pfm_syswide_force_stop, ctx, 1);
	DPRINT(("called CPU%d for cleanup ret=%d\n", ctx->ctx_cpu, ret));
}
#endif /* CONFIG_SMP */

/*
 * called for each close(). Partially free resources.
 * When caller is self-monitoring, the context is unloaded.
 */
static int
pfm_flush(struct file *filp, fl_owner_t id)
{
	pfm_context_t *ctx;
	struct task_struct *task;
	struct pt_regs *regs;
	unsigned long flags;
	unsigned long smpl_buf_size = 0UL;
	void *smpl_buf_vaddr = NULL;
	int state, is_system;

	if (PFM_IS_FILE(filp) == 0) {
		DPRINT(("bad magic for\n"));
		return -EBADF;
	}

	ctx = (pfm_context_t *)filp->private_data;
	if (ctx == NULL) {
		printk(KERN_ERR "perfmon: pfm_flush: NULL ctx [%d]\n", task_pid_nr(current));
		return -EBADF;
	}

	/*
	 * remove our file from the async queue, if we use this mode.
	 * This can be done without the context being protected. We come
	 * here when the context has become unreachable by other tasks.
	 *
	 * We may still have active monitoring at this point and we may
	 * end up in pfm_overflow_handler(). However, fasync_helper()
	 * operates with interrupts disabled and it cleans up the
	 * queue. If the PMU handler is called prior to entering
	 * fasync_helper() then it will send a signal. If it is
	 * invoked after, it will find an empty queue and no
	 * signal will be sent. In both case, we are safe
	 */
	PROTECT_CTX(ctx, flags);

	state     = ctx->ctx_state;
	is_system = ctx->ctx_fl_system;

	task = PFM_CTX_TASK(ctx);
	regs = task_pt_regs(task);

	DPRINT(("ctx_state=%d is_current=%d\n",
		state,
		task == current ? 1 : 0));

	/*
	 * if state == UNLOADED, then task is NULL
	 */

	/*
	 * we must stop and unload because we are losing access to the context.
	 */
	if (task == current) {
#ifdef CONFIG_SMP
		/*
		 * the task IS the owner but it migrated to another CPU: that's bad
		 * but we must handle this cleanly. Unfortunately, the kernel does
		 * not provide a mechanism to block migration (while the context is loaded).
		 *
		 * We need to release the resource on the ORIGINAL cpu.
		 */
		if (is_system && ctx->ctx_cpu != smp_processor_id()) {

			DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
			/*
			 * keep context protected but unmask interrupt for IPI
			 */
			local_irq_restore(flags);

			pfm_syswide_cleanup_other_cpu(ctx);

			/*
			 * restore interrupt masking
			 */
			local_irq_save(flags);

			/*
			 * context is unloaded at this point
			 */
		} else
#endif /* CONFIG_SMP */
		{

			DPRINT(("forcing unload\n"));
			/*
		 	* stop and unload, returning with state UNLOADED
		 	* and session unreserved.
		 	*/
			pfm_context_unload(ctx, NULL, 0, regs);

			DPRINT(("ctx_state=%d\n", ctx->ctx_state));
		}
	}

	/*
	 * remove virtual mapping, if any, for the calling task.
	 * cannot reset ctx field until last user is calling close().
	 *
	 * ctx_smpl_vaddr must never be cleared because it is needed
	 * by every task with access to the context
	 *
	 * When called from do_exit(), the mm context is gone already, therefore
	 * mm is NULL, i.e., the VMA is already gone  and we do not have to
	 * do anything here
	 */
	if (ctx->ctx_smpl_vaddr && current->mm) {
		smpl_buf_vaddr = ctx->ctx_smpl_vaddr;
		smpl_buf_size  = ctx->ctx_smpl_size;
	}

	UNPROTECT_CTX(ctx, flags);

	/*
	 * if there was a mapping, then we systematically remove it
	 * at this point. Cannot be done inside critical section
	 * because some VM function reenables interrupts.
	 *
	 */
	if (smpl_buf_vaddr) pfm_remove_smpl_mapping(current, smpl_buf_vaddr, smpl_buf_size);

	return 0;
}
/*
 * called either on explicit close() or from exit_files(). 
 * Only the LAST user of the file gets to this point, i.e., it is
 * called only ONCE.
 *
 * IMPORTANT: we get called ONLY when the refcnt on the file gets to zero 
 * (fput()),i.e, last task to access the file. Nobody else can access the 
 * file at this point.
 *
 * When called from exit_files(), the VMA has been freed because exit_mm()
 * is executed before exit_files().
 *
 * When called from exit_files(), the current task is not yet ZOMBIE but we
 * flush the PMU state to the context. 
 */
static int
pfm_close(struct inode *inode, struct file *filp)
{
	pfm_context_t *ctx;
	struct task_struct *task;
	struct pt_regs *regs;
  	DECLARE_WAITQUEUE(wait, current);
	unsigned long flags;
	unsigned long smpl_buf_size = 0UL;
	void *smpl_buf_addr = NULL;
	int free_possible = 1;
	int state, is_system;

	DPRINT(("pfm_close called private=%p\n", filp->private_data));

	if (PFM_IS_FILE(filp) == 0) {
		DPRINT(("bad magic\n"));
		return -EBADF;
	}
	
	ctx = (pfm_context_t *)filp->private_data;
	if (ctx == NULL) {
		printk(KERN_ERR "perfmon: pfm_close: NULL ctx [%d]\n", task_pid_nr(current));
		return -EBADF;
	}

	PROTECT_CTX(ctx, flags);

	state     = ctx->ctx_state;
	is_system = ctx->ctx_fl_system;

	task = PFM_CTX_TASK(ctx);
	regs = task_pt_regs(task);

	DPRINT(("ctx_state=%d is_current=%d\n", 
		state,
		task == current ? 1 : 0));

	/*
	 * if task == current, then pfm_flush() unloaded the context
	 */
	if (state == PFM_CTX_UNLOADED) goto doit;

	/*
	 * context is loaded/masked and task != current, we need to
	 * either force an unload or go zombie
	 */

	/*
	 * The task is currently blocked or will block after an overflow.
	 * we must force it to wakeup to get out of the
	 * MASKED state and transition to the unloaded state by itself.
	 *
	 * This situation is only possible for per-task mode
	 */
	if (state == PFM_CTX_MASKED && CTX_OVFL_NOBLOCK(ctx) == 0) {

		/*
		 * set a "partial" zombie state to be checked
		 * upon return from down() in pfm_handle_work().
		 *
		 * We cannot use the ZOMBIE state, because it is checked
		 * by pfm_load_regs() which is called upon wakeup from down().
		 * In such case, it would free the context and then we would
		 * return to pfm_handle_work() which would access the
		 * stale context. Instead, we set a flag invisible to pfm_load_regs()
		 * but visible to pfm_handle_work().
		 *
		 * For some window of time, we have a zombie context with
		 * ctx_state = MASKED  and not ZOMBIE
		 */
		ctx->ctx_fl_going_zombie = 1;

		/*
		 * force task to wake up from MASKED state
		 */
		complete(&ctx->ctx_restart_done);

		DPRINT(("waking up ctx_state=%d\n", state));

		/*
		 * put ourself to sleep waiting for the other
		 * task to report completion
		 *
		 * the context is protected by mutex, therefore there
		 * is no risk of being notified of completion before
		 * begin actually on the waitq.
		 */
  		set_current_state(TASK_INTERRUPTIBLE);
  		add_wait_queue(&ctx->ctx_zombieq, &wait);

		UNPROTECT_CTX(ctx, flags);

		/*
		 * XXX: check for signals :
		 * 	- ok for explicit close
		 * 	- not ok when coming from exit_files()
		 */
      		schedule();


		PROTECT_CTX(ctx, flags);


		remove_wait_queue(&ctx->ctx_zombieq, &wait);
  		set_current_state(TASK_RUNNING);

		/*
		 * context is unloaded at this point
		 */
		DPRINT(("after zombie wakeup ctx_state=%d for\n", state));
	}
	else if (task != current) {
#ifdef CONFIG_SMP
		/*
	 	 * switch context to zombie state
	 	 */
		ctx->ctx_state = PFM_CTX_ZOMBIE;

		DPRINT(("zombie ctx for [%d]\n", task_pid_nr(task)));
		/*
		 * cannot free the context on the spot. deferred until
		 * the task notices the ZOMBIE state
		 */
		free_possible = 0;
#else
		pfm_context_unload(ctx, NULL, 0, regs);
#endif
	}

doit:
	/* reload state, may have changed during  opening of critical section */
	state = ctx->ctx_state;

	/*
	 * the context is still attached to a task (possibly current)
	 * we cannot destroy it right now
	 */

	/*
	 * we must free the sampling buffer right here because
	 * we cannot rely on it being cleaned up later by the
	 * monitored task. It is not possible to free vmalloc'ed
	 * memory in pfm_load_regs(). Instead, we remove the buffer
	 * now. should there be subsequent PMU overflow originally
	 * meant for sampling, the will be converted to spurious
	 * and that's fine because the monitoring tools is gone anyway.
	 */
	if (ctx->ctx_smpl_hdr) {
		smpl_buf_addr = ctx->ctx_smpl_hdr;
		smpl_buf_size = ctx->ctx_smpl_size;
		/* no more sampling */
		ctx->ctx_smpl_hdr = NULL;
		ctx->ctx_fl_is_sampling = 0;
	}

	DPRINT(("ctx_state=%d free_possible=%d addr=%p size=%lu\n",
		state,
		free_possible,
		smpl_buf_addr,
		smpl_buf_size));

	if (smpl_buf_addr) pfm_exit_smpl_buffer(ctx->ctx_buf_fmt);

	/*
	 * UNLOADED that the session has already been unreserved.
	 */
	if (state == PFM_CTX_ZOMBIE) {
		pfm_unreserve_session(ctx, ctx->ctx_fl_system , ctx->ctx_cpu);
	}

	/*
	 * disconnect file descriptor from context must be done
	 * before we unlock.
	 */
	filp->private_data = NULL;

	/*
	 * if we free on the spot, the context is now completely unreachable
	 * from the callers side. The monitored task side is also cut, so we
	 * can freely cut.
	 *
	 * If we have a deferred free, only the caller side is disconnected.
	 */
	UNPROTECT_CTX(ctx, flags);

	/*
	 * All memory free operations (especially for vmalloc'ed memory)
	 * MUST be done with interrupts ENABLED.
	 */
	if (smpl_buf_addr)  pfm_rvfree(smpl_buf_addr, smpl_buf_size);

	/*
	 * return the memory used by the context
	 */
	if (free_possible) pfm_context_free(ctx);

	return 0;
}

static int
pfm_no_open(struct inode *irrelevant, struct file *dontcare)
{
	DPRINT(("pfm_no_open called\n"));
	return -ENXIO;
}



static const struct file_operations pfm_file_ops = {
	.llseek		= no_llseek,
	.read		= pfm_read,
	.write		= pfm_write,
	.poll		= pfm_poll,
	.unlocked_ioctl = pfm_ioctl,
	.open		= pfm_no_open,	/* special open code to disallow open via /proc */
	.fasync		= pfm_fasync,
	.release	= pfm_close,
	.flush		= pfm_flush
};

static int
pfmfs_delete_dentry(struct dentry *dentry)
{
	return 1;
}

static const struct dentry_operations pfmfs_dentry_operations = {
	.d_delete = pfmfs_delete_dentry,
};


static struct file *
pfm_alloc_file(pfm_context_t *ctx)
{
	struct file *file;
	struct inode *inode;
	struct path path;
	char name[32];
	struct qstr this;

	/*
	 * allocate a new inode
	 */
	inode = new_inode(pfmfs_mnt->mnt_sb);
	if (!inode)
		return ERR_PTR(-ENOMEM);

	DPRINT(("new inode ino=%ld @%p\n", inode->i_ino, inode));

	inode->i_mode = S_IFCHR|S_IRUGO;
	inode->i_uid  = current_fsuid();
	inode->i_gid  = current_fsgid();

	sprintf(name, "[%lu]", inode->i_ino);
	this.name = name;
	this.len  = strlen(name);
	this.hash = inode->i_ino;

	/*
	 * allocate a new dcache entry
	 */
	path.dentry = d_alloc(pfmfs_mnt->mnt_sb->s_root, &this);
	if (!path.dentry) {
		iput(inode);
		return ERR_PTR(-ENOMEM);
	}
	path.mnt = mntget(pfmfs_mnt);

	path.dentry->d_op = &pfmfs_dentry_operations;
	d_add(path.dentry, inode);

	file = alloc_file(&path, FMODE_READ, &pfm_file_ops);
	if (!file) {
		path_put(&path);
		return ERR_PTR(-ENFILE);
	}

	file->f_flags = O_RDONLY;
	file->private_data = ctx;

	return file;
}

static int
pfm_remap_buffer(struct vm_area_struct *vma, unsigned long buf, unsigned long addr, unsigned long size)
{
	DPRINT(("CPU%d buf=0x%lx addr=0x%lx size=%ld\n", smp_processor_id(), buf, addr, size));

	while (size > 0) {
		unsigned long pfn = ia64_tpa(buf) >> PAGE_SHIFT;


		if (remap_pfn_range(vma, addr, pfn, PAGE_SIZE, PAGE_READONLY))
			return -ENOMEM;

		addr  += PAGE_SIZE;
		buf   += PAGE_SIZE;
		size  -= PAGE_SIZE;
	}
	return 0;
}

/*
 * allocate a sampling buffer and remaps it into the user address space of the task
 */
static int
pfm_smpl_buffer_alloc(struct task_struct *task, struct file *filp, pfm_context_t *ctx, unsigned long rsize, void **user_vaddr)
{
	struct mm_struct *mm = task->mm;
	struct vm_area_struct *vma = NULL;
	unsigned long size;
	void *smpl_buf;


	/*
	 * the fixed header + requested size and align to page boundary
	 */
	size = PAGE_ALIGN(rsize);

	DPRINT(("sampling buffer rsize=%lu size=%lu bytes\n", rsize, size));

	/*
	 * check requested size to avoid Denial-of-service attacks
	 * XXX: may have to refine this test
	 * Check against address space limit.
	 *
	 * if ((mm->total_vm << PAGE_SHIFT) + len> task->rlim[RLIMIT_AS].rlim_cur)
	 * 	return -ENOMEM;
	 */
	if (size > task_rlimit(task, RLIMIT_MEMLOCK))
		return -ENOMEM;

	/*
	 * We do the easy to undo allocations first.
 	 *
	 * pfm_rvmalloc(), clears the buffer, so there is no leak
	 */
	smpl_buf = pfm_rvmalloc(size);
	if (smpl_buf == NULL) {
		DPRINT(("Can't allocate sampling buffer\n"));
		return -ENOMEM;
	}

	DPRINT(("smpl_buf @%p\n", smpl_buf));

	/* allocate vma */
	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
	if (!vma) {
		DPRINT(("Cannot allocate vma\n"));
		goto error_kmem;
	}
	INIT_LIST_HEAD(&vma->anon_vma_chain);

	/*
	 * partially initialize the vma for the sampling buffer
	 */
	vma->vm_mm	     = mm;
	vma->vm_file	     = filp;
	vma->vm_flags	     = VM_READ| VM_MAYREAD |VM_RESERVED;
	vma->vm_page_prot    = PAGE_READONLY; /* XXX may need to change */

	/*
	 * Now we have everything we need and we can initialize
	 * and connect all the data structures
	 */

	ctx->ctx_smpl_hdr   = smpl_buf;
	ctx->ctx_smpl_size  = size; /* aligned size */

	/*
	 * Let's do the difficult operations next.
	 *
	 * now we atomically find some area in the address space and
	 * remap the buffer in it.
	 */
	down_write(&task->mm->mmap_sem);

	/* find some free area in address space, must have mmap sem held */
	vma->vm_start = pfm_get_unmapped_area(NULL, 0, size, 0, MAP_PRIVATE|MAP_ANONYMOUS, 0);
	if (vma->vm_start == 0UL) {
		DPRINT(("Cannot find unmapped area for size %ld\n", size));
		up_write(&task->mm->mmap_sem);
		goto error;
	}
	vma->vm_end = vma->vm_start + size;
	vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;

	DPRINT(("aligned size=%ld, hdr=%p mapped @0x%lx\n", size, ctx->ctx_smpl_hdr, vma->vm_start));

	/* can only be applied to current task, need to have the mm semaphore held when called */
	if (pfm_remap_buffer(vma, (unsigned long)smpl_buf, vma->vm_start, size)) {
		DPRINT(("Can't remap buffer\n"));
		up_write(&task->mm->mmap_sem);
		goto error;
	}

	get_file(filp);

	/*
	 * now insert the vma in the vm list for the process, must be
	 * done with mmap lock held
	 */
	insert_vm_struct(mm, vma);

	mm->total_vm  += size >> PAGE_SHIFT;
	vm_stat_account(vma->vm_mm, vma->vm_flags, vma->vm_file,
							vma_pages(vma));
	up_write(&task->mm->mmap_sem);

	/*
	 * keep track of user level virtual address
	 */
	ctx->ctx_smpl_vaddr = (void *)vma->vm_start;
	*(unsigned long *)user_vaddr = vma->vm_start;

	return 0;

error:
	kmem_cache_free(vm_area_cachep, vma);
error_kmem:
	pfm_rvfree(smpl_buf, size);

	return -ENOMEM;
}

/*
 * XXX: do something better here
 */
static int
pfm_bad_permissions(struct task_struct *task)
{
	const struct cred *tcred;
	uid_t uid = current_uid();
	gid_t gid = current_gid();
	int ret;

	rcu_read_lock();
	tcred = __task_cred(task);

	/* inspired by ptrace_attach() */
	DPRINT(("cur: uid=%d gid=%d task: euid=%d suid=%d uid=%d egid=%d sgid=%d\n",
		uid,
		gid,
		tcred->euid,
		tcred->suid,
		tcred->uid,
		tcred->egid,
		tcred->sgid));

	ret = ((uid != tcred->euid)
	       || (uid != tcred->suid)
	       || (uid != tcred->uid)
	       || (gid != tcred->egid)
	       || (gid != tcred->sgid)
	       || (gid != tcred->gid)) && !capable(CAP_SYS_PTRACE);

	rcu_read_unlock();
	return ret;
}

static int
pfarg_is_sane(struct task_struct *task, pfarg_context_t *pfx)
{
	int ctx_flags;

	/* valid signal */

	ctx_flags = pfx->ctx_flags;

	if (ctx_flags & PFM_FL_SYSTEM_WIDE) {

		/*
		 * cannot block in this mode
		 */
		if (ctx_flags & PFM_FL_NOTIFY_BLOCK) {
			DPRINT(("cannot use blocking mode when in system wide monitoring\n"));
			return -EINVAL;
		}
	} else {
	}
	/* probably more to add here */

	return 0;
}

static int
pfm_setup_buffer_fmt(struct task_struct *task, struct file *filp, pfm_context_t *ctx, unsigned int ctx_flags,
		     unsigned int cpu, pfarg_context_t *arg)
{
	pfm_buffer_fmt_t *fmt = NULL;
	unsigned long size = 0UL;
	void *uaddr = NULL;
	void *fmt_arg = NULL;
	int ret = 0;
#define PFM_CTXARG_BUF_ARG(a)	(pfm_buffer_fmt_t *)(a+1)

	/* invoke and lock buffer format, if found */
	fmt = pfm_find_buffer_fmt(arg->ctx_smpl_buf_id);
	if (fmt == NULL) {
		DPRINT(("[%d] cannot find buffer format\n", task_pid_nr(task)));
		return -EINVAL;
	}

	/*
	 * buffer argument MUST be contiguous to pfarg_context_t
	 */
	if (fmt->fmt_arg_size) fmt_arg = PFM_CTXARG_BUF_ARG(arg);

	ret = pfm_buf_fmt_validate(fmt, task, ctx_flags, cpu, fmt_arg);

	DPRINT(("[%d] after validate(0x%x,%d,%p)=%d\n", task_pid_nr(task), ctx_flags, cpu, fmt_arg, ret));

	if (ret) goto error;

	/* link buffer format and context */
	ctx->ctx_buf_fmt = fmt;
	ctx->ctx_fl_is_sampling = 1; /* assume record() is defined */

	/*
	 * check if buffer format wants to use perfmon buffer allocation/mapping service
	 */
	ret = pfm_buf_fmt_getsize(fmt, task, ctx_flags, cpu, fmt_arg, &size);
	if (ret) goto error;

	if (size) {
		/*
		 * buffer is always remapped into the caller's address space
		 */
		ret = pfm_smpl_buffer_alloc(current, filp, ctx, size, &uaddr);
		if (ret) goto error;

		/* keep track of user address of buffer */
		arg->ctx_smpl_vaddr = uaddr;
	}
	ret = pfm_buf_fmt_init(fmt, task, ctx->ctx_smpl_hdr, ctx_flags, cpu, fmt_arg);

error:
	return ret;
}

static void
pfm_reset_pmu_state(pfm_context_t *ctx)
{
	int i;

	/*
	 * install reset values for PMC.
	 */
	for (i=1; PMC_IS_LAST(i) == 0; i++) {
		if (PMC_IS_IMPL(i) == 0) continue;
		ctx->ctx_pmcs[i] = PMC_DFL_VAL(i);
		DPRINT(("pmc[%d]=0x%lx\n", i, ctx->ctx_pmcs[i]));
	}
	/*
	 * PMD registers are set to 0UL when the context in memset()
	 */

	/*
	 * On context switched restore, we must restore ALL pmc and ALL pmd even
	 * when they are not actively used by the task. In UP, the incoming process
	 * may otherwise pick up left over PMC, PMD state from the previous process.
	 * As opposed to PMD, stale PMC can cause harm to the incoming
	 * process because they may change what is being measured.
	 * Therefore, we must systematically reinstall the entire
	 * PMC state. In SMP, the same thing is possible on the
	 * same CPU but also on between 2 CPUs.
	 *
	 * The problem with PMD is information leaking especially
	 * to user level when psr.sp=0
	 *
	 * There is unfortunately no easy way to avoid this problem
	 * on either UP or SMP. This definitively slows down the
	 * pfm_load_regs() function.
	 */

	 /*
	  * bitmask of all PMCs accessible to this context
	  *
	  * PMC0 is treated differently.
	  */
	ctx->ctx_all_pmcs[0] = pmu_conf->impl_pmcs[0] & ~0x1;

	/*
	 * bitmask of all PMDs that are accessible to this context
	 */
	ctx->ctx_all_pmds[0] = pmu_conf->impl_pmds[0];

	DPRINT(("<%d> all_pmcs=0x%lx all_pmds=0x%lx\n", ctx->ctx_fd, ctx->ctx_all_pmcs[0],ctx->ctx_all_pmds[0]));

	/*
	 * useful in case of re-enable after disable
	 */
	ctx->ctx_used_ibrs[0] = 0UL;
	ctx->ctx_used_dbrs[0] = 0UL;
}

static int
pfm_ctx_getsize(void *arg, size_t *sz)
{
	pfarg_context_t *req = (pfarg_context_t *)arg;
	pfm_buffer_fmt_t *fmt;

	*sz = 0;

	if (!pfm_uuid_cmp(req->ctx_smpl_buf_id, pfm_null_uuid)) return 0;

	fmt = pfm_find_buffer_fmt(req->ctx_smpl_buf_id);
	if (fmt == NULL) {
		DPRINT(("cannot find buffer format\n"));
		return -EINVAL;
	}
	/* get just enough to copy in user parameters */
	*sz = fmt->fmt_arg_size;
	DPRINT(("arg_size=%lu\n", *sz));

	return 0;
}



/*
 * cannot attach if :
 * 	- kernel task
 * 	- task not owned by caller
 * 	- task incompatible with context mode
 */
static int
pfm_task_incompatible(pfm_context_t *ctx, struct task_struct *task)
{
	/*
	 * no kernel task or task not owner by caller
	 */
	if (task->mm == NULL) {
		DPRINT(("task [%d] has not memory context (kernel thread)\n", task_pid_nr(task)));
		return -EPERM;
	}
	if (pfm_bad_permissions(task)) {
		DPRINT(("no permission to attach to  [%d]\n", task_pid_nr(task)));
		return -EPERM;
	}
	/*
	 * cannot block in self-monitoring mode
	 */
	if (CTX_OVFL_NOBLOCK(ctx) == 0 && task == current) {
		DPRINT(("cannot load a blocking context on self for [%d]\n", task_pid_nr(task)));
		return -EINVAL;
	}

	if (task->exit_state == EXIT_ZOMBIE) {
		DPRINT(("cannot attach to  zombie task [%d]\n", task_pid_nr(task)));
		return -EBUSY;
	}

	/*
	 * always ok for self
	 */
	if (task == current) return 0;

	if (!task_is_stopped_or_traced(task)) {
		DPRINT(("cannot attach to non-stopped task [%d] state=%ld\n", task_pid_nr(task), task->state));
		return -EBUSY;
	}
	/*
	 * make sure the task is off any CPU
	 */
	wait_task_inactive(task, 0);

	/* more to come... */

	return 0;
}

static int
pfm_get_task(pfm_context_t *ctx, pid_t pid, struct task_struct **task)
{
	struct task_struct *p = current;
	int ret;

	/* XXX: need to add more checks here */
	if (pid < 2) return -EPERM;

	if (pid != task_pid_vnr(current)) {

		read_lock(&tasklist_lock);

		p = find_task_by_vpid(pid);

		/* make sure task cannot go away while we operate on it */
		if (p) get_task_struct(p);

		read_unlock(&tasklist_lock);

		if (p == NULL) return -ESRCH;
	}

	ret = pfm_task_incompatible(ctx, p);
	if (ret == 0) {
		*task = p;
	} else if (p != current) {
		pfm_put_task(p);
	}
	return ret;
}



static int
pfm_context_create(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	pfarg_context_t *req = (pfarg_context_t *)arg;
	struct file *filp;
	struct path path;
	int ctx_flags;
	int fd;
	int ret;

	/* let's check the arguments first */
	ret = pfarg_is_sane(current, req);
	if (ret < 0)
		return ret;

	ctx_flags = req->ctx_flags;

	ret = -ENOMEM;

	fd = get_unused_fd();
	if (fd < 0)
		return fd;

	ctx = pfm_context_alloc(ctx_flags);
	if (!ctx)
		goto error;

	filp = pfm_alloc_file(ctx);
	if (IS_ERR(filp)) {
		ret = PTR_ERR(filp);
		goto error_file;
	}

	req->ctx_fd = ctx->ctx_fd = fd;

	/*
	 * does the user want to sample?
	 */
	if (pfm_uuid_cmp(req->ctx_smpl_buf_id, pfm_null_uuid)) {
		ret = pfm_setup_buffer_fmt(current, filp, ctx, ctx_flags, 0, req);
		if (ret)
			goto buffer_error;
	}

	DPRINT(("ctx=%p flags=0x%x system=%d notify_block=%d excl_idle=%d no_msg=%d ctx_fd=%d\n",
		ctx,
		ctx_flags,
		ctx->ctx_fl_system,
		ctx->ctx_fl_block,
		ctx->ctx_fl_excl_idle,
		ctx->ctx_fl_no_msg,
		ctx->ctx_fd));

	/*
	 * initialize soft PMU state
	 */
	pfm_reset_pmu_state(ctx);

	fd_install(fd, filp);

	return 0;

buffer_error:
	path = filp->f_path;
	put_filp(filp);
	path_put(&path);

	if (ctx->ctx_buf_fmt) {
		pfm_buf_fmt_exit(ctx->ctx_buf_fmt, current, NULL, regs);
	}
error_file:
	pfm_context_free(ctx);

error:
	put_unused_fd(fd);
	return ret;
}

static inline unsigned long
pfm_new_counter_value (pfm_counter_t *reg, int is_long_reset)
{
	unsigned long val = is_long_reset ? reg->long_reset : reg->short_reset;
	unsigned long new_seed, old_seed = reg->seed, mask = reg->mask;
	extern unsigned long carta_random32 (unsigned long seed);

	if (reg->flags & PFM_REGFL_RANDOM) {
		new_seed = carta_random32(old_seed);
		val -= (old_seed & mask);	/* counter values are negative numbers! */
		if ((mask >> 32) != 0)
			/* construct a full 64-bit random value: */
			new_seed |= carta_random32(old_seed >> 32) << 32;
		reg->seed = new_seed;
	}
	reg->lval = val;
	return val;
}

static void
pfm_reset_regs_masked(pfm_context_t *ctx, unsigned long *ovfl_regs, int is_long_reset)
{
	unsigned long mask = ovfl_regs[0];
	unsigned long reset_others = 0UL;
	unsigned long val;
	int i;

	/*
	 * now restore reset value on sampling overflowed counters
	 */
	mask >>= PMU_FIRST_COUNTER;
	for(i = PMU_FIRST_COUNTER; mask; i++, mask >>= 1) {

		if ((mask & 0x1UL) == 0UL) continue;

		ctx->ctx_pmds[i].val = val = pfm_new_counter_value(ctx->ctx_pmds+ i, is_long_reset);
		reset_others        |= ctx->ctx_pmds[i].reset_pmds[0];

		DPRINT_ovfl((" %s reset ctx_pmds[%d]=%lx\n", is_long_reset ? "long" : "short", i, val));
	}

	/*
	 * Now take care of resetting the other registers
	 */
	for(i = 0; reset_others; i++, reset_others >>= 1) {

		if ((reset_others & 0x1) == 0) continue;

		ctx->ctx_pmds[i].val = val = pfm_new_counter_value(ctx->ctx_pmds + i, is_long_reset);

		DPRINT_ovfl(("%s reset_others pmd[%d]=%lx\n",
			  is_long_reset ? "long" : "short", i, val));
	}
}

static void
pfm_reset_regs(pfm_context_t *ctx, unsigned long *ovfl_regs, int is_long_reset)
{
	unsigned long mask = ovfl_regs[0];
	unsigned long reset_others = 0UL;
	unsigned long val;
	int i;

	DPRINT_ovfl(("ovfl_regs=0x%lx is_long_reset=%d\n", ovfl_regs[0], is_long_reset));

	if (ctx->ctx_state == PFM_CTX_MASKED) {
		pfm_reset_regs_masked(ctx, ovfl_regs, is_long_reset);
		return;
	}

	/*
	 * now restore reset value on sampling overflowed counters
	 */
	mask >>= PMU_FIRST_COUNTER;
	for(i = PMU_FIRST_COUNTER; mask; i++, mask >>= 1) {

		if ((mask & 0x1UL) == 0UL) continue;

		val           = pfm_new_counter_value(ctx->ctx_pmds+ i, is_long_reset);
		reset_others |= ctx->ctx_pmds[i].reset_pmds[0];

		DPRINT_ovfl((" %s reset ctx_pmds[%d]=%lx\n", is_long_reset ? "long" : "short", i, val));

		pfm_write_soft_counter(ctx, i, val);
	}

	/*
	 * Now take care of resetting the other registers
	 */
	for(i = 0; reset_others; i++, reset_others >>= 1) {

		if ((reset_others & 0x1) == 0) continue;

		val = pfm_new_counter_value(ctx->ctx_pmds + i, is_long_reset);

		if (PMD_IS_COUNTING(i)) {
			pfm_write_soft_counter(ctx, i, val);
		} else {
			ia64_set_pmd(i, val);
		}
		DPRINT_ovfl(("%s reset_others pmd[%d]=%lx\n",
			  is_long_reset ? "long" : "short", i, val));
	}
	ia64_srlz_d();
}

static int
pfm_write_pmcs(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	struct task_struct *task;
	pfarg_reg_t *req = (pfarg_reg_t *)arg;
	unsigned long value, pmc_pm;
	unsigned long smpl_pmds, reset_pmds, impl_pmds;
	unsigned int cnum, reg_flags, flags, pmc_type;
	int i, can_access_pmu = 0, is_loaded, is_system, expert_mode;
	int is_monitor, is_counting, state;
	int ret = -EINVAL;
	pfm_reg_check_t	wr_func;
#define PFM_CHECK_PMC_PM(x, y, z) ((x)->ctx_fl_system ^ PMC_PM(y, z))

	state     = ctx->ctx_state;
	is_loaded = state == PFM_CTX_LOADED ? 1 : 0;
	is_system = ctx->ctx_fl_system;
	task      = ctx->ctx_task;
	impl_pmds = pmu_conf->impl_pmds[0];

	if (state == PFM_CTX_ZOMBIE) return -EINVAL;

	if (is_loaded) {
		/*
		 * In system wide and when the context is loaded, access can only happen
		 * when the caller is running on the CPU being monitored by the session.
		 * It does not have to be the owner (ctx_task) of the context per se.
		 */
		if (is_system && ctx->ctx_cpu != smp_processor_id()) {
			DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
			return -EBUSY;
		}
		can_access_pmu = GET_PMU_OWNER() == task || is_system ? 1 : 0;
	}
	expert_mode = pfm_sysctl.expert_mode; 

	for (i = 0; i < count; i++, req++) {

		cnum       = req->reg_num;
		reg_flags  = req->reg_flags;
		value      = req->reg_value;
		smpl_pmds  = req->reg_smpl_pmds[0];
		reset_pmds = req->reg_reset_pmds[0];
		flags      = 0;


		if (cnum >= PMU_MAX_PMCS) {
			DPRINT(("pmc%u is invalid\n", cnum));
			goto error;
		}

		pmc_type   = pmu_conf->pmc_desc[cnum].type;
		pmc_pm     = (value >> pmu_conf->pmc_desc[cnum].pm_pos) & 0x1;
		is_counting = (pmc_type & PFM_REG_COUNTING) == PFM_REG_COUNTING ? 1 : 0;
		is_monitor  = (pmc_type & PFM_REG_MONITOR) == PFM_REG_MONITOR ? 1 : 0;

		/*
		 * we reject all non implemented PMC as well
		 * as attempts to modify PMC[0-3] which are used
		 * as status registers by the PMU
		 */
		if ((pmc_type & PFM_REG_IMPL) == 0 || (pmc_type & PFM_REG_CONTROL) == PFM_REG_CONTROL) {
			DPRINT(("pmc%u is unimplemented or no-access pmc_type=%x\n", cnum, pmc_type));
			goto error;
		}
		wr_func = pmu_conf->pmc_desc[cnum].write_check;
		/*
		 * If the PMC is a monitor, then if the value is not the default:
		 * 	- system-wide session: PMCx.pm=1 (privileged monitor)
		 * 	- per-task           : PMCx.pm=0 (user monitor)
		 */
		if (is_monitor && value != PMC_DFL_VAL(cnum) && is_system ^ pmc_pm) {
			DPRINT(("pmc%u pmc_pm=%lu is_system=%d\n",
				cnum,
				pmc_pm,
				is_system));
			goto error;
		}

		if (is_counting) {
			/*
		 	 * enforce generation of overflow interrupt. Necessary on all
		 	 * CPUs.
		 	 */
			value |= 1 << PMU_PMC_OI;

			if (reg_flags & PFM_REGFL_OVFL_NOTIFY) {
				flags |= PFM_REGFL_OVFL_NOTIFY;
			}

			if (reg_flags & PFM_REGFL_RANDOM) flags |= PFM_REGFL_RANDOM;

			/* verify validity of smpl_pmds */
			if ((smpl_pmds & impl_pmds) != smpl_pmds) {
				DPRINT(("invalid smpl_pmds 0x%lx for pmc%u\n", smpl_pmds, cnum));
				goto error;
			}

			/* verify validity of reset_pmds */
			if ((reset_pmds & impl_pmds) != reset_pmds) {
				DPRINT(("invalid reset_pmds 0x%lx for pmc%u\n", reset_pmds, cnum));
				goto error;
			}
		} else {
			if (reg_flags & (PFM_REGFL_OVFL_NOTIFY|PFM_REGFL_RANDOM)) {
				DPRINT(("cannot set ovfl_notify or random on pmc%u\n", cnum));
				goto error;
			}
			/* eventid on non-counting monitors are ignored */
		}

		/*
		 * execute write checker, if any
		 */
		if (likely(expert_mode == 0 && wr_func)) {
			ret = (*wr_func)(task, ctx, cnum, &value, regs);
			if (ret) goto error;
			ret = -EINVAL;
		}

		/*
		 * no error on this register
		 */
		PFM_REG_RETFLAG_SET(req->reg_flags, 0);

		/*
		 * Now we commit the changes to the software state
		 */

		/*
		 * update overflow information
		 */
		if (is_counting) {
			/*
		 	 * full flag update each time a register is programmed
		 	 */
			ctx->ctx_pmds[cnum].flags = flags;

			ctx->ctx_pmds[cnum].reset_pmds[0] = reset_pmds;
			ctx->ctx_pmds[cnum].smpl_pmds[0]  = smpl_pmds;
			ctx->ctx_pmds[cnum].eventid       = req->reg_smpl_eventid;

			/*
			 * Mark all PMDS to be accessed as used.
			 *
			 * We do not keep track of PMC because we have to
			 * systematically restore ALL of them.
			 *
			 * We do not update the used_monitors mask, because
			 * if we have not programmed them, then will be in
			 * a quiescent state, therefore we will not need to
			 * mask/restore then when context is MASKED.
			 */
			CTX_USED_PMD(ctx, reset_pmds);
			CTX_USED_PMD(ctx, smpl_pmds);
			/*
		 	 * make sure we do not try to reset on
		 	 * restart because we have established new values
		 	 */
			if (state == PFM_CTX_MASKED) ctx->ctx_ovfl_regs[0] &= ~1UL << cnum;
		}
		/*
		 * Needed in case the user does not initialize the equivalent
		 * PMD. Clearing is done indirectly via pfm_reset_pmu_state() so there is no
		 * possible leak here.
		 */
		CTX_USED_PMD(ctx, pmu_conf->pmc_desc[cnum].dep_pmd[0]);

		/*
		 * keep track of the monitor PMC that we are using.
		 * we save the value of the pmc in ctx_pmcs[] and if
		 * the monitoring is not stopped for the context we also
		 * place it in the saved state area so that it will be
		 * picked up later by the context switch code.
		 *
		 * The value in ctx_pmcs[] can only be changed in pfm_write_pmcs().
		 *
		 * The value in th_pmcs[] may be modified on overflow, i.e.,  when
		 * monitoring needs to be stopped.
		 */
		if (is_monitor) CTX_USED_MONITOR(ctx, 1UL << cnum);

		/*
		 * update context state
		 */
		ctx->ctx_pmcs[cnum] = value;

		if (is_loaded) {
			/*
			 * write thread state
			 */
			if (is_system == 0) ctx->th_pmcs[cnum] = value;

			/*
			 * write hardware register if we can
			 */
			if (can_access_pmu) {
				ia64_set_pmc(cnum, value);
			}
#ifdef CONFIG_SMP
			else {
				/*
				 * per-task SMP only here
				 *
			 	 * we are guaranteed that the task is not running on the other CPU,
			 	 * we indicate that this PMD will need to be reloaded if the task
			 	 * is rescheduled on the CPU it ran last on.
			 	 */
				ctx->ctx_reload_pmcs[0] |= 1UL << cnum;
			}
#endif
		}

		DPRINT(("pmc[%u]=0x%lx ld=%d apmu=%d flags=0x%x all_pmcs=0x%lx used_pmds=0x%lx eventid=%ld smpl_pmds=0x%lx reset_pmds=0x%lx reloads_pmcs=0x%lx used_monitors=0x%lx ovfl_regs=0x%lx\n",
			  cnum,
			  value,
			  is_loaded,
			  can_access_pmu,
			  flags,
			  ctx->ctx_all_pmcs[0],
			  ctx->ctx_used_pmds[0],
			  ctx->ctx_pmds[cnum].eventid,
			  smpl_pmds,
			  reset_pmds,
			  ctx->ctx_reload_pmcs[0],
			  ctx->ctx_used_monitors[0],
			  ctx->ctx_ovfl_regs[0]));
	}

	/*
	 * make sure the changes are visible
	 */
	if (can_access_pmu) ia64_srlz_d();

	return 0;
error:
	PFM_REG_RETFLAG_SET(req->reg_flags, PFM_REG_RETFL_EINVAL);
	return ret;
}

static int
pfm_write_pmds(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	struct task_struct *task;
	pfarg_reg_t *req = (pfarg_reg_t *)arg;
	unsigned long value, hw_value, ovfl_mask;
	unsigned int cnum;
	int i, can_access_pmu = 0, state;
	int is_counting, is_loaded, is_system, expert_mode;
	int ret = -EINVAL;
	pfm_reg_check_t wr_func;


	state     = ctx->ctx_state;
	is_loaded = state == PFM_CTX_LOADED ? 1 : 0;
	is_system = ctx->ctx_fl_system;
	ovfl_mask = pmu_conf->ovfl_val;
	task      = ctx->ctx_task;

	if (unlikely(state == PFM_CTX_ZOMBIE)) return -EINVAL;

	/*
	 * on both UP and SMP, we can only write to the PMC when the task is
	 * the owner of the local PMU.
	 */
	if (likely(is_loaded)) {
		/*
		 * In system wide and when the context is loaded, access can only happen
		 * when the caller is running on the CPU being monitored by the session.
		 * It does not have to be the owner (ctx_task) of the context per se.
		 */
		if (unlikely(is_system && ctx->ctx_cpu != smp_processor_id())) {
			DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
			return -EBUSY;
		}
		can_access_pmu = GET_PMU_OWNER() == task || is_system ? 1 : 0;
	}
	expert_mode = pfm_sysctl.expert_mode; 

	for (i = 0; i < count; i++, req++) {

		cnum  = req->reg_num;
		value = req->reg_value;

		if (!PMD_IS_IMPL(cnum)) {
			DPRINT(("pmd[%u] is unimplemented or invalid\n", cnum));
			goto abort_mission;
		}
		is_counting = PMD_IS_COUNTING(cnum);
		wr_func     = pmu_conf->pmd_desc[cnum].write_check;

		/*
		 * execute write checker, if any
		 */
		if (unlikely(expert_mode == 0 && wr_func)) {
			unsigned long v = value;

			ret = (*wr_func)(task, ctx, cnum, &v, regs);
			if (ret) goto abort_mission;

			value = v;
			ret   = -EINVAL;
		}

		/*
		 * no error on this register
		 */
		PFM_REG_RETFLAG_SET(req->reg_flags, 0);

		/*
		 * now commit changes to software state
		 */
		hw_value = value;

		/*
		 * update virtualized (64bits) counter
		 */
		if (is_counting) {
			/*
			 * write context state
			 */
			ctx->ctx_pmds[cnum].lval = value;

			/*
			 * when context is load we use the split value
			 */
			if (is_loaded) {
				hw_value = value &  ovfl_mask;
				value    = value & ~ovfl_mask;
			}
		}
		/*
		 * update reset values (not just for counters)
		 */
		ctx->ctx_pmds[cnum].long_reset  = req->reg_long_reset;
		ctx->ctx_pmds[cnum].short_reset = req->reg_short_reset;

		/*
		 * update randomization parameters (not just for counters)
		 */
		ctx->ctx_pmds[cnum].seed = req->reg_random_seed;
		ctx->ctx_pmds[cnum].mask = req->reg_random_mask;

		/*
		 * update context value
		 */
		ctx->ctx_pmds[cnum].val  = value;

		/*
		 * Keep track of what we use
		 *
		 * We do not keep track of PMC because we have to
		 * systematically restore ALL of them.
		 */
		CTX_USED_PMD(ctx, PMD_PMD_DEP(cnum));

		/*
		 * mark this PMD register used as well
		 */
		CTX_USED_PMD(ctx, RDEP(cnum));

		/*
		 * make sure we do not try to reset on
		 * restart because we have established new values
		 */
		if (is_counting && state == PFM_CTX_MASKED) {
			ctx->ctx_ovfl_regs[0] &= ~1UL << cnum;
		}

		if (is_loaded) {
			/*
		 	 * write thread state
		 	 */
			if (is_system == 0) ctx->th_pmds[cnum] = hw_value;

			/*
			 * write hardware register if we can
			 */
			if (can_access_pmu) {
				ia64_set_pmd(cnum, hw_value);
			} else {
#ifdef CONFIG_SMP
				/*
			 	 * we are guaranteed that the task is not running on the other CPU,
			 	 * we indicate that this PMD will need to be reloaded if the task
			 	 * is rescheduled on the CPU it ran last on.
			 	 */
				ctx->ctx_reload_pmds[0] |= 1UL << cnum;
#endif
			}
		}

		DPRINT(("pmd[%u]=0x%lx ld=%d apmu=%d, hw_value=0x%lx ctx_pmd=0x%lx  short_reset=0x%lx "
			  "long_reset=0x%lx notify=%c seed=0x%lx mask=0x%lx used_pmds=0x%lx reset_pmds=0x%lx reload_pmds=0x%lx all_pmds=0x%lx ovfl_regs=0x%lx\n",
			cnum,
			value,
			is_loaded,
			can_access_pmu,
			hw_value,
			ctx->ctx_pmds[cnum].val,
			ctx->ctx_pmds[cnum].short_reset,
			ctx->ctx_pmds[cnum].long_reset,
			PMC_OVFL_NOTIFY(ctx, cnum) ? 'Y':'N',
			ctx->ctx_pmds[cnum].seed,
			ctx->ctx_pmds[cnum].mask,
			ctx->ctx_used_pmds[0],
			ctx->ctx_pmds[cnum].reset_pmds[0],
			ctx->ctx_reload_pmds[0],
			ctx->ctx_all_pmds[0],
			ctx->ctx_ovfl_regs[0]));
	}

	/*
	 * make changes visible
	 */
	if (can_access_pmu) ia64_srlz_d();

	return 0;

abort_mission:
	/*
	 * for now, we have only one possibility for error
	 */
	PFM_REG_RETFLAG_SET(req->reg_flags, PFM_REG_RETFL_EINVAL);
	return ret;
}

/*
 * By the way of PROTECT_CONTEXT(), interrupts are masked while we are in this function.
 * Therefore we know, we do not have to worry about the PMU overflow interrupt. If an
 * interrupt is delivered during the call, it will be kept pending until we leave, making
 * it appears as if it had been generated at the UNPROTECT_CONTEXT(). At least we are
 * guaranteed to return consistent data to the user, it may simply be old. It is not
 * trivial to treat the overflow while inside the call because you may end up in
 * some module sampling buffer code causing deadlocks.
 */
static int
pfm_read_pmds(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	struct task_struct *task;
	unsigned long val = 0UL, lval, ovfl_mask, sval;
	pfarg_reg_t *req = (pfarg_reg_t *)arg;
	unsigned int cnum, reg_flags = 0;
	int i, can_access_pmu = 0, state;
	int is_loaded, is_system, is_counting, expert_mode;
	int ret = -EINVAL;
	pfm_reg_check_t rd_func;

	/*
	 * access is possible when loaded only for
	 * self-monitoring tasks or in UP mode
	 */

	state     = ctx->ctx_state;
	is_loaded = state == PFM_CTX_LOADED ? 1 : 0;
	is_system = ctx->ctx_fl_system;
	ovfl_mask = pmu_conf->ovfl_val;
	task      = ctx->ctx_task;

	if (state == PFM_CTX_ZOMBIE) return -EINVAL;

	if (likely(is_loaded)) {
		/*
		 * In system wide and when the context is loaded, access can only happen
		 * when the caller is running on the CPU being monitored by the session.
		 * It does not have to be the owner (ctx_task) of the context per se.
		 */
		if (unlikely(is_system && ctx->ctx_cpu != smp_processor_id())) {
			DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
			return -EBUSY;
		}
		/*
		 * this can be true when not self-monitoring only in UP
		 */
		can_access_pmu = GET_PMU_OWNER() == task || is_system ? 1 : 0;

		if (can_access_pmu) ia64_srlz_d();
	}
	expert_mode = pfm_sysctl.expert_mode; 

	DPRINT(("ld=%d apmu=%d ctx_state=%d\n",
		is_loaded,
		can_access_pmu,
		state));

	/*
	 * on both UP and SMP, we can only read the PMD from the hardware register when
	 * the task is the owner of the local PMU.
	 */

	for (i = 0; i < count; i++, req++) {

		cnum        = req->reg_num;
		reg_flags   = req->reg_flags;

		if (unlikely(!PMD_IS_IMPL(cnum))) goto error;
		/*
		 * we can only read the register that we use. That includes
		 * the one we explicitly initialize AND the one we want included
		 * in the sampling buffer (smpl_regs).
		 *
		 * Having this restriction allows optimization in the ctxsw routine
		 * without compromising security (leaks)
		 */
		if (unlikely(!CTX_IS_USED_PMD(ctx, cnum))) goto error;

		sval        = ctx->ctx_pmds[cnum].val;
		lval        = ctx->ctx_pmds[cnum].lval;
		is_counting = PMD_IS_COUNTING(cnum);

		/*
		 * If the task is not the current one, then we check if the
		 * PMU state is still in the local live register due to lazy ctxsw.
		 * If true, then we read directly from the registers.
		 */
		if (can_access_pmu){
			val = ia64_get_pmd(cnum);
		} else {
			/*
			 * context has been saved
			 * if context is zombie, then task does not exist anymore.
			 * In this case, we use the full value saved in the context (pfm_flush_regs()).
			 */
			val = is_loaded ? ctx->th_pmds[cnum] : 0UL;
		}
		rd_func = pmu_conf->pmd_desc[cnum].read_check;

		if (is_counting) {
			/*
			 * XXX: need to check for overflow when loaded
			 */
			val &= ovfl_mask;
			val += sval;
		}

		/*
		 * execute read checker, if any
		 */
		if (unlikely(expert_mode == 0 && rd_func)) {
			unsigned long v = val;
			ret = (*rd_func)(ctx->ctx_task, ctx, cnum, &v, regs);
			if (ret) goto error;
			val = v;
			ret = -EINVAL;
		}

		PFM_REG_RETFLAG_SET(reg_flags, 0);

		DPRINT(("pmd[%u]=0x%lx\n", cnum, val));

		/*
		 * update register return value, abort all if problem during copy.
		 * we only modify the reg_flags field. no check mode is fine because
		 * access has been verified upfront in sys_perfmonctl().
		 */
		req->reg_value            = val;
		req->reg_flags            = reg_flags;
		req->reg_last_reset_val   = lval;
	}

	return 0;

error:
	PFM_REG_RETFLAG_SET(req->reg_flags, PFM_REG_RETFL_EINVAL);
	return ret;
}

int
pfm_mod_write_pmcs(struct task_struct *task, void *req, unsigned int nreq, struct pt_regs *regs)
{
	pfm_context_t *ctx;

	if (req == NULL) return -EINVAL;

 	ctx = GET_PMU_CTX();

	if (ctx == NULL) return -EINVAL;

	/*
	 * for now limit to current task, which is enough when calling
	 * from overflow handler
	 */
	if (task != current && ctx->ctx_fl_system == 0) return -EBUSY;

	return pfm_write_pmcs(ctx, req, nreq, regs);
}
EXPORT_SYMBOL(pfm_mod_write_pmcs);

int
pfm_mod_read_pmds(struct task_struct *task, void *req, unsigned int nreq, struct pt_regs *regs)
{
	pfm_context_t *ctx;

	if (req == NULL) return -EINVAL;

 	ctx = GET_PMU_CTX();

	if (ctx == NULL) return -EINVAL;

	/*
	 * for now limit to current task, which is enough when calling
	 * from overflow handler
	 */
	if (task != current && ctx->ctx_fl_system == 0) return -EBUSY;

	return pfm_read_pmds(ctx, req, nreq, regs);
}
EXPORT_SYMBOL(pfm_mod_read_pmds);

/*
 * Only call this function when a process it trying to
 * write the debug registers (reading is always allowed)
 */
int
pfm_use_debug_registers(struct task_struct *task)
{
	pfm_context_t *ctx = task->thread.pfm_context;
	unsigned long flags;
	int ret = 0;

	if (pmu_conf->use_rr_dbregs == 0) return 0;

	DPRINT(("called for [%d]\n", task_pid_nr(task)));

	/*
	 * do it only once
	 */
	if (task->thread.flags & IA64_THREAD_DBG_VALID) return 0;

	/*
	 * Even on SMP, we do not need to use an atomic here because
	 * the only way in is via ptrace() and this is possible only when the
	 * process is stopped. Even in the case where the ctxsw out is not totally
	 * completed by the time we come here, there is no way the 'stopped' process
	 * could be in the middle of fiddling with the pfm_write_ibr_dbr() routine.
	 * So this is always safe.
	 */
	if (ctx && ctx->ctx_fl_using_dbreg == 1) return -1;

	LOCK_PFS(flags);

	/*
	 * We cannot allow setting breakpoints when system wide monitoring
	 * sessions are using the debug registers.
	 */
	if (pfm_sessions.pfs_sys_use_dbregs> 0)
		ret = -1;
	else
		pfm_sessions.pfs_ptrace_use_dbregs++;

	DPRINT(("ptrace_use_dbregs=%u  sys_use_dbregs=%u by [%d] ret = %d\n",
		  pfm_sessions.pfs_ptrace_use_dbregs,
		  pfm_sessions.pfs_sys_use_dbregs,
		  task_pid_nr(task), ret));

	UNLOCK_PFS(flags);

	return ret;
}

/*
 * This function is called for every task that exits with the
 * IA64_THREAD_DBG_VALID set. This indicates a task which was
 * able to use the debug registers for debugging purposes via
 * ptrace(). Therefore we know it was not using them for
 * performance monitoring, so we only decrement the number
 * of "ptraced" debug register users to keep the count up to date
 */
int
pfm_release_debug_registers(struct task_struct *task)
{
	unsigned long flags;
	int ret;

	if (pmu_conf->use_rr_dbregs == 0) return 0;

	LOCK_PFS(flags);
	if (pfm_sessions.pfs_ptrace_use_dbregs == 0) {
		printk(KERN_ERR "perfmon: invalid release for [%d] ptrace_use_dbregs=0\n", task_pid_nr(task));
		ret = -1;
	}  else {
		pfm_sessions.pfs_ptrace_use_dbregs--;
		ret = 0;
	}
	UNLOCK_PFS(flags);

	return ret;
}

static int
pfm_restart(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	struct task_struct *task;
	pfm_buffer_fmt_t *fmt;
	pfm_ovfl_ctrl_t rst_ctrl;
	int state, is_system;
	int ret = 0;

	state     = ctx->ctx_state;
	fmt       = ctx->ctx_buf_fmt;
	is_system = ctx->ctx_fl_system;
	task      = PFM_CTX_TASK(ctx);

	switch(state) {
		case PFM_CTX_MASKED:
			break;
		case PFM_CTX_LOADED: 
			if (CTX_HAS_SMPL(ctx) && fmt->fmt_restart_active) break;
			/* fall through */
		case PFM_CTX_UNLOADED:
		case PFM_CTX_ZOMBIE:
			DPRINT(("invalid state=%d\n", state));
			return -EBUSY;
		default:
			DPRINT(("state=%d, cannot operate (no active_restart handler)\n", state));
			return -EINVAL;
	}

	/*
 	 * In system wide and when the context is loaded, access can only happen
 	 * when the caller is running on the CPU being monitored by the session.
 	 * It does not have to be the owner (ctx_task) of the context per se.
 	 */
	if (is_system && ctx->ctx_cpu != smp_processor_id()) {
		DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
		return -EBUSY;
	}

	/* sanity check */
	if (unlikely(task == NULL)) {
		printk(KERN_ERR "perfmon: [%d] pfm_restart no task\n", task_pid_nr(current));
		return -EINVAL;
	}

	if (task == current || is_system) {

		fmt = ctx->ctx_buf_fmt;

		DPRINT(("restarting self %d ovfl=0x%lx\n",
			task_pid_nr(task),
			ctx->ctx_ovfl_regs[0]));

		if (CTX_HAS_SMPL(ctx)) {

			prefetch(ctx->ctx_smpl_hdr);

			rst_ctrl.bits.mask_monitoring = 0;
			rst_ctrl.bits.reset_ovfl_pmds = 0;

			if (state == PFM_CTX_LOADED)
				ret = pfm_buf_fmt_restart_active(fmt, task, &rst_ctrl, ctx->ctx_smpl_hdr, regs);
			else
				ret = pfm_buf_fmt_restart(fmt, task, &rst_ctrl, ctx->ctx_smpl_hdr, regs);
		} else {
			rst_ctrl.bits.mask_monitoring = 0;
			rst_ctrl.bits.reset_ovfl_pmds = 1;
		}

		if (ret == 0) {
			if (rst_ctrl.bits.reset_ovfl_pmds)
				pfm_reset_regs(ctx, ctx->ctx_ovfl_regs, PFM_PMD_LONG_RESET);

			if (rst_ctrl.bits.mask_monitoring == 0) {
				DPRINT(("resuming monitoring for [%d]\n", task_pid_nr(task)));

				if (state == PFM_CTX_MASKED) pfm_restore_monitoring(task);
			} else {
				DPRINT(("keeping monitoring stopped for [%d]\n", task_pid_nr(task)));

				// cannot use pfm_stop_monitoring(task, regs);
			}
		}
		/*
		 * clear overflowed PMD mask to remove any stale information
		 */
		ctx->ctx_ovfl_regs[0] = 0UL;

		/*
		 * back to LOADED state
		 */
		ctx->ctx_state = PFM_CTX_LOADED;

		/*
		 * XXX: not really useful for self monitoring
		 */
		ctx->ctx_fl_can_restart = 0;

		return 0;
	}

	/* 
	 * restart another task
	 */

	/*
	 * When PFM_CTX_MASKED, we cannot issue a restart before the previous 
	 * one is seen by the task.
	 */
	if (state == PFM_CTX_MASKED) {
		if (ctx->ctx_fl_can_restart == 0) return -EINVAL;
		/*
		 * will prevent subsequent restart before this one is
		 * seen by other task
		 */
		ctx->ctx_fl_can_restart = 0;
	}

	/*
	 * if blocking, then post the semaphore is PFM_CTX_MASKED, i.e.
	 * the task is blocked or on its way to block. That's the normal
	 * restart path. If the monitoring is not masked, then the task
	 * can be actively monitoring and we cannot directly intervene.
	 * Therefore we use the trap mechanism to catch the task and
	 * force it to reset the buffer/reset PMDs.
	 *
	 * if non-blocking, then we ensure that the task will go into
	 * pfm_handle_work() before returning to user mode.
	 *
	 * We cannot explicitly reset another task, it MUST always
	 * be done by the task itself. This works for system wide because
	 * the tool that is controlling the session is logically doing 
	 * "self-monitoring".
	 */
	if (CTX_OVFL_NOBLOCK(ctx) == 0 && state == PFM_CTX_MASKED) {
		DPRINT(("unblocking [%d]\n", task_pid_nr(task)));
		complete(&ctx->ctx_restart_done);
	} else {
		DPRINT(("[%d] armed exit trap\n", task_pid_nr(task)));

		ctx->ctx_fl_trap_reason = PFM_TRAP_REASON_RESET;

		PFM_SET_WORK_PENDING(task, 1);

		set_notify_resume(task);

		/*
		 * XXX: send reschedule if task runs on another CPU
		 */
	}
	return 0;
}

static int
pfm_debug(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	unsigned int m = *(unsigned int *)arg;

	pfm_sysctl.debug = m == 0 ? 0 : 1;

	printk(KERN_INFO "perfmon debugging %s (timing reset)\n", pfm_sysctl.debug ? "on" : "off");

	if (m == 0) {
		memset(pfm_stats, 0, sizeof(pfm_stats));
		for(m=0; m < NR_CPUS; m++) pfm_stats[m].pfm_ovfl_intr_cycles_min = ~0UL;
	}
	return 0;
}

/*
 * arg can be NULL and count can be zero for this function
 */
static int
pfm_write_ibr_dbr(int mode, pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	struct thread_struct *thread = NULL;
	struct task_struct *task;
	pfarg_dbreg_t *req = (pfarg_dbreg_t *)arg;
	unsigned long flags;
	dbreg_t dbreg;
	unsigned int rnum;
	int first_time;
	int ret = 0, state;
	int i, can_access_pmu = 0;
	int is_system, is_loaded;

	if (pmu_conf->use_rr_dbregs == 0) return -EINVAL;

	state     = ctx->ctx_state;
	is_loaded = state == PFM_CTX_LOADED ? 1 : 0;
	is_system = ctx->ctx_fl_system;
	task      = ctx->ctx_task;

	if (state == PFM_CTX_ZOMBIE) return -EINVAL;

	/*
	 * on both UP and SMP, we can only write to the PMC when the task is
	 * the owner of the local PMU.
	 */
	if (is_loaded) {
		thread = &task->thread;
		/*
		 * In system wide and when the context is loaded, access can only happen
		 * when the caller is running on the CPU being monitored by the session.
		 * It does not have to be the owner (ctx_task) of the context per se.
		 */
		if (unlikely(is_system && ctx->ctx_cpu != smp_processor_id())) {
			DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
			return -EBUSY;
		}
		can_access_pmu = GET_PMU_OWNER() == task || is_system ? 1 : 0;
	}

	/*
	 * we do not need to check for ipsr.db because we do clear ibr.x, dbr.r, and dbr.w
	 * ensuring that no real breakpoint can be installed via this call.
	 *
	 * IMPORTANT: regs can be NULL in this function
	 */

	first_time = ctx->ctx_fl_using_dbreg == 0;

	/*
	 * don't bother if we are loaded and task is being debugged
	 */
	if (is_loaded && (thread->flags & IA64_THREAD_DBG_VALID) != 0) {
		DPRINT(("debug registers already in use for [%d]\n", task_pid_nr(task)));
		return -EBUSY;
	}

	/*
	 * check for debug registers in system wide mode
	 *
	 * If though a check is done in pfm_context_load(),
	 * we must repeat it here, in case the registers are
	 * written after the context is loaded
	 */
	if (is_loaded) {
		LOCK_PFS(flags);

		if (first_time && is_system) {
			if (pfm_sessions.pfs_ptrace_use_dbregs)
				ret = -EBUSY;
			else
				pfm_sessions.pfs_sys_use_dbregs++;
		}
		UNLOCK_PFS(flags);
	}

	if (ret != 0) return ret;

	/*
	 * mark ourself as user of the debug registers for
	 * perfmon purposes.
	 */
	ctx->ctx_fl_using_dbreg = 1;

	/*
 	 * clear hardware registers to make sure we don't
 	 * pick up stale state.
	 *
	 * for a system wide session, we do not use
	 * thread.dbr, thread.ibr because this process
	 * never leaves the current CPU and the state
	 * is shared by all processes running on it
 	 */
	if (first_time && can_access_pmu) {
		DPRINT(("[%d] clearing ibrs, dbrs\n", task_pid_nr(task)));
		for (i=0; i < pmu_conf->num_ibrs; i++) {
			ia64_set_ibr(i, 0UL);
			ia64_dv_serialize_instruction();
		}
		ia64_srlz_i();
		for (i=0; i < pmu_conf->num_dbrs; i++) {
			ia64_set_dbr(i, 0UL);
			ia64_dv_serialize_data();
		}
		ia64_srlz_d();
	}

	/*
	 * Now install the values into the registers
	 */
	for (i = 0; i < count; i++, req++) {

		rnum      = req->dbreg_num;
		dbreg.val = req->dbreg_value;

		ret = -EINVAL;

		if ((mode == PFM_CODE_RR && rnum >= PFM_NUM_IBRS) || ((mode == PFM_DATA_RR) && rnum >= PFM_NUM_DBRS)) {
			DPRINT(("invalid register %u val=0x%lx mode=%d i=%d count=%d\n",
				  rnum, dbreg.val, mode, i, count));

			goto abort_mission;
		}

		/*
		 * make sure we do not install enabled breakpoint
		 */
		if (rnum & 0x1) {
			if (mode == PFM_CODE_RR)
				dbreg.ibr.ibr_x = 0;
			else
				dbreg.dbr.dbr_r = dbreg.dbr.dbr_w = 0;
		}

		PFM_REG_RETFLAG_SET(req->dbreg_flags, 0);

		/*
		 * Debug registers, just like PMC, can only be modified
		 * by a kernel call. Moreover, perfmon() access to those
		 * registers are centralized in this routine. The hardware
		 * does not modify the value of these registers, therefore,
		 * if we save them as they are written, we can avoid having
		 * to save them on context switch out. This is made possible
		 * by the fact that when perfmon uses debug registers, ptrace()
		 * won't be able to modify them concurrently.
		 */
		if (mode == PFM_CODE_RR) {
			CTX_USED_IBR(ctx, rnum);

			if (can_access_pmu) {
				ia64_set_ibr(rnum, dbreg.val);
				ia64_dv_serialize_instruction();
			}

			ctx->ctx_ibrs[rnum] = dbreg.val;

			DPRINT(("write ibr%u=0x%lx used_ibrs=0x%x ld=%d apmu=%d\n",
				rnum, dbreg.val, ctx->ctx_used_ibrs[0], is_loaded, can_access_pmu));
		} else {
			CTX_USED_DBR(ctx, rnum);

			if (can_access_pmu) {
				ia64_set_dbr(rnum, dbreg.val);
				ia64_dv_serialize_data();
			}
			ctx->ctx_dbrs[rnum] = dbreg.val;

			DPRINT(("write dbr%u=0x%lx used_dbrs=0x%x ld=%d apmu=%d\n",
				rnum, dbreg.val, ctx->ctx_used_dbrs[0], is_loaded, can_access_pmu));
		}
	}

	return 0;

abort_mission:
	/*
	 * in case it was our first attempt, we undo the global modifications
	 */
	if (first_time) {
		LOCK_PFS(flags);
		if (ctx->ctx_fl_system) {
			pfm_sessions.pfs_sys_use_dbregs--;
		}
		UNLOCK_PFS(flags);
		ctx->ctx_fl_using_dbreg = 0;
	}
	/*
	 * install error return flag
	 */
	PFM_REG_RETFLAG_SET(req->dbreg_flags, PFM_REG_RETFL_EINVAL);

	return ret;
}

static int
pfm_write_ibrs(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	return pfm_write_ibr_dbr(PFM_CODE_RR, ctx, arg, count, regs);
}

static int
pfm_write_dbrs(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	return pfm_write_ibr_dbr(PFM_DATA_RR, ctx, arg, count, regs);
}

int
pfm_mod_write_ibrs(struct task_struct *task, void *req, unsigned int nreq, struct pt_regs *regs)
{
	pfm_context_t *ctx;

	if (req == NULL) return -EINVAL;

 	ctx = GET_PMU_CTX();

	if (ctx == NULL) return -EINVAL;

	/*
	 * for now limit to current task, which is enough when calling
	 * from overflow handler
	 */
	if (task != current && ctx->ctx_fl_system == 0) return -EBUSY;

	return pfm_write_ibrs(ctx, req, nreq, regs);
}
EXPORT_SYMBOL(pfm_mod_write_ibrs);

int
pfm_mod_write_dbrs(struct task_struct *task, void *req, unsigned int nreq, struct pt_regs *regs)
{
	pfm_context_t *ctx;

	if (req == NULL) return -EINVAL;

 	ctx = GET_PMU_CTX();

	if (ctx == NULL) return -EINVAL;

	/*
	 * for now limit to current task, which is enough when calling
	 * from overflow handler
	 */
	if (task != current && ctx->ctx_fl_system == 0) return -EBUSY;

	return pfm_write_dbrs(ctx, req, nreq, regs);
}
EXPORT_SYMBOL(pfm_mod_write_dbrs);


static int
pfm_get_features(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	pfarg_features_t *req = (pfarg_features_t *)arg;

	req->ft_version = PFM_VERSION;
	return 0;
}

static int
pfm_stop(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	struct pt_regs *tregs;
	struct task_struct *task = PFM_CTX_TASK(ctx);
	int state, is_system;

	state     = ctx->ctx_state;
	is_system = ctx->ctx_fl_system;

	/*
	 * context must be attached to issue the stop command (includes LOADED,MASKED,ZOMBIE)
	 */
	if (state == PFM_CTX_UNLOADED) return -EINVAL;

	/*
 	 * In system wide and when the context is loaded, access can only happen
 	 * when the caller is running on the CPU being monitored by the session.
 	 * It does not have to be the owner (ctx_task) of the context per se.
 	 */
	if (is_system && ctx->ctx_cpu != smp_processor_id()) {
		DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
		return -EBUSY;
	}
	DPRINT(("task [%d] ctx_state=%d is_system=%d\n",
		task_pid_nr(PFM_CTX_TASK(ctx)),
		state,
		is_system));
	/*
	 * in system mode, we need to update the PMU directly
	 * and the user level state of the caller, which may not
	 * necessarily be the creator of the context.
	 */
	if (is_system) {
		/*
		 * Update local PMU first
		 *
		 * disable dcr pp
		 */
		ia64_setreg(_IA64_REG_CR_DCR, ia64_getreg(_IA64_REG_CR_DCR) & ~IA64_DCR_PP);
		ia64_srlz_i();

		/*
		 * update local cpuinfo
		 */
		PFM_CPUINFO_CLEAR(PFM_CPUINFO_DCR_PP);

		/*
		 * stop monitoring, does srlz.i
		 */
		pfm_clear_psr_pp();

		/*
		 * stop monitoring in the caller
		 */
		ia64_psr(regs)->pp = 0;

		return 0;
	}
	/*
	 * per-task mode
	 */

	if (task == current) {
		/* stop monitoring  at kernel level */
		pfm_clear_psr_up();

		/*
	 	 * stop monitoring at the user level
	 	 */
		ia64_psr(regs)->up = 0;
	} else {
		tregs = task_pt_regs(task);

		/*
	 	 * stop monitoring at the user level
	 	 */
		ia64_psr(tregs)->up = 0;

		/*
		 * monitoring disabled in kernel at next reschedule
		 */
		ctx->ctx_saved_psr_up = 0;
		DPRINT(("task=[%d]\n", task_pid_nr(task)));
	}
	return 0;
}


static int
pfm_start(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	struct pt_regs *tregs;
	int state, is_system;

	state     = ctx->ctx_state;
	is_system = ctx->ctx_fl_system;

	if (state != PFM_CTX_LOADED) return -EINVAL;

	/*
 	 * In system wide and when the context is loaded, access can only happen
 	 * when the caller is running on the CPU being monitored by the session.
 	 * It does not have to be the owner (ctx_task) of the context per se.
 	 */
	if (is_system && ctx->ctx_cpu != smp_processor_id()) {
		DPRINT(("should be running on CPU%d\n", ctx->ctx_cpu));
		return -EBUSY;
	}

	/*
	 * in system mode, we need to update the PMU directly
	 * and the user level state of the caller, which may not
	 * necessarily be the creator of the context.
	 */
	if (is_system) {

		/*
		 * set user level psr.pp for the caller
		 */
		ia64_psr(regs)->pp = 1;

		/*
		 * now update the local PMU and cpuinfo
		 */
		PFM_CPUINFO_SET(PFM_CPUINFO_DCR_PP);

		/*
		 * start monitoring at kernel level
		 */
		pfm_set_psr_pp();

		/* enable dcr pp */
		ia64_setreg(_IA64_REG_CR_DCR, ia64_getreg(_IA64_REG_CR_DCR) | IA64_DCR_PP);
		ia64_srlz_i();

		return 0;
	}

	/*
	 * per-process mode
	 */

	if (ctx->ctx_task == current) {

		/* start monitoring at kernel level */
		pfm_set_psr_up();

		/*
		 * activate monitoring at user level
		 */
		ia64_psr(regs)->up = 1;

	} else {
		tregs = task_pt_regs(ctx->ctx_task);

		/*
		 * start monitoring at the kernel level the next
		 * time the task is scheduled
		 */
		ctx->ctx_saved_psr_up = IA64_PSR_UP;

		/*
		 * activate monitoring at user level
		 */
		ia64_psr(tregs)->up = 1;
	}
	return 0;
}

static int
pfm_get_pmc_reset(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	pfarg_reg_t *req = (pfarg_reg_t *)arg;
	unsigned int cnum;
	int i;
	int ret = -EINVAL;

	for (i = 0; i < count; i++, req++) {

		cnum = req->reg_num;

		if (!PMC_IS_IMPL(cnum)) goto abort_mission;

		req->reg_value = PMC_DFL_VAL(cnum);

		PFM_REG_RETFLAG_SET(req->reg_flags, 0);

		DPRINT(("pmc_reset_val pmc[%u]=0x%lx\n", cnum, req->reg_value));
	}
	return 0;

abort_mission:
	PFM_REG_RETFLAG_SET(req->reg_flags, PFM_REG_RETFL_EINVAL);
	return ret;
}

static int
pfm_check_task_exist(pfm_context_t *ctx)
{
	struct task_struct *g, *t;
	int ret = -ESRCH;

	read_lock(&tasklist_lock);

	do_each_thread (g, t) {
		if (t->thread.pfm_context == ctx) {
			ret = 0;
			goto out;
		}
	} while_each_thread (g, t);
out:
	read_unlock(&tasklist_lock);

	DPRINT(("pfm_check_task_exist: ret=%d ctx=%p\n", ret, ctx));

	return ret;
}

static int
pfm_context_load(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	struct task_struct *task;
	struct thread_struct *thread;
	struct pfm_context_t *old;
	unsigned long flags;
#ifndef CONFIG_SMP
	struct task_struct *owner_task = NULL;
#endif
	pfarg_load_t *req = (pfarg_load_t *)arg;
	unsigned long *pmcs_source, *pmds_source;
	int the_cpu;
	int ret = 0;
	int state, is_system, set_dbregs = 0;

	state     = ctx->ctx_state;
	is_system = ctx->ctx_fl_system;
	/*
	 * can only load from unloaded or terminated state
	 */
	if (state != PFM_CTX_UNLOADED) {
		DPRINT(("cannot load to [%d], invalid ctx_state=%d\n",
			req->load_pid,
			ctx->ctx_state));
		return -EBUSY;
	}

	DPRINT(("load_pid [%d] using_dbreg=%d\n", req->load_pid, ctx->ctx_fl_using_dbreg));

	if (CTX_OVFL_NOBLOCK(ctx) == 0 && req->load_pid == current->pid) {
		DPRINT(("cannot use blocking mode on self\n"));
		return -EINVAL;
	}

	ret = pfm_get_task(ctx, req->load_pid, &task);
	if (ret) {
		DPRINT(("load_pid [%d] get_task=%d\n", req->load_pid, ret));
		return ret;
	}

	ret = -EINVAL;

	/*
	 * system wide is self monitoring only
	 */
	if (is_system && task != current) {
		DPRINT(("system wide is self monitoring only load_pid=%d\n",
			req->load_pid));
		goto error;
	}

	thread = &task->thread;

	ret = 0;
	/*
	 * cannot load a context which is using range restrictions,
	 * into a task that is being debugged.
	 */
	if (ctx->ctx_fl_using_dbreg) {
		if (thread->flags & IA64_THREAD_DBG_VALID) {
			ret = -EBUSY;
			DPRINT(("load_pid [%d] task is debugged, cannot load range restrictions\n", req->load_pid));
			goto error;
		}
		LOCK_PFS(flags);

		if (is_system) {
			if (pfm_sessions.pfs_ptrace_use_dbregs) {
				DPRINT(("cannot load [%d] dbregs in use\n",
							task_pid_nr(task)));
				ret = -EBUSY;
			} else {
				pfm_sessions.pfs_sys_use_dbregs++;
				DPRINT(("load [%d] increased sys_use_dbreg=%u\n", task_pid_nr(task), pfm_sessions.pfs_sys_use_dbregs));
				set_dbregs = 1;
			}
		}

		UNLOCK_PFS(flags);

		if (ret) goto error;
	}

	/*
	 * SMP system-wide monitoring implies self-monitoring.
	 *
	 * The programming model expects the task to
	 * be pinned on a CPU throughout the session.
	 * Here we take note of the current CPU at the
	 * time the context is loaded. No call from
	 * another CPU will be allowed.
	 *
	 * The pinning via shed_setaffinity()
	 * must be done by the calling task prior
	 * to this call.
	 *
	 * systemwide: keep track of CPU this session is supposed to run on
	 */
	the_cpu = ctx->ctx_cpu = smp_processor_id();

	ret = -EBUSY;
	/*
	 * now reserve the session
	 */
	ret = pfm_reserve_session(current, is_system, the_cpu);
	if (ret) goto error;

	/*
	 * task is necessarily stopped at this point.
	 *
	 * If the previous context was zombie, then it got removed in
	 * pfm_save_regs(). Therefore we should not see it here.
	 * If we see a context, then this is an active context
	 *
	 * XXX: needs to be atomic
	 */
	DPRINT(("before cmpxchg() old_ctx=%p new_ctx=%p\n",
		thread->pfm_context, ctx));

	ret = -EBUSY;
	old = ia64_cmpxchg(acq, &thread->pfm_context, NULL, ctx, sizeof(pfm_context_t *));
	if (old != NULL) {
		DPRINT(("load_pid [%d] already has a context\n", req->load_pid));
		goto error_unres;
	}

	pfm_reset_msgq(ctx);

	ctx->ctx_state = PFM_CTX_LOADED;

	/*
	 * link context to task
	 */
	ctx->ctx_task = task;

	if (is_system) {
		/*
		 * we load as stopped
		 */
		PFM_CPUINFO_SET(PFM_CPUINFO_SYST_WIDE);
		PFM_CPUINFO_CLEAR(PFM_CPUINFO_DCR_PP);

		if (ctx->ctx_fl_excl_idle) PFM_CPUINFO_SET(PFM_CPUINFO_EXCL_IDLE);
	} else {
		thread->flags |= IA64_THREAD_PM_VALID;
	}

	/*
	 * propagate into thread-state
	 */
	pfm_copy_pmds(task, ctx);
	pfm_copy_pmcs(task, ctx);

	pmcs_source = ctx->th_pmcs;
	pmds_source = ctx->th_pmds;

	/*
	 * always the case for system-wide
	 */
	if (task == current) {

		if (is_system == 0) {

			/* allow user level control */
			ia64_psr(regs)->sp = 0;
			DPRINT(("clearing psr.sp for [%d]\n", task_pid_nr(task)));

			SET_LAST_CPU(ctx, smp_processor_id());
			INC_ACTIVATION();
			SET_ACTIVATION(ctx);
#ifndef CONFIG_SMP
			/*
			 * push the other task out, if any
			 */
			owner_task = GET_PMU_OWNER();
			if (owner_task) pfm_lazy_save_regs(owner_task);
#endif
		}
		/*
		 * load all PMD from ctx to PMU (as opposed to thread state)
		 * restore all PMC from ctx to PMU
		 */
		pfm_restore_pmds(pmds_source, ctx->ctx_all_pmds[0]);
		pfm_restore_pmcs(pmcs_source, ctx->ctx_all_pmcs[0]);

		ctx->ctx_reload_pmcs[0] = 0UL;
		ctx->ctx_reload_pmds[0] = 0UL;

		/*
		 * guaranteed safe by earlier check against DBG_VALID
		 */
		if (ctx->ctx_fl_using_dbreg) {
			pfm_restore_ibrs(ctx->ctx_ibrs, pmu_conf->num_ibrs);
			pfm_restore_dbrs(ctx->ctx_dbrs, pmu_conf->num_dbrs);
		}
		/*
		 * set new ownership
		 */
		SET_PMU_OWNER(task, ctx);

		DPRINT(("context loaded on PMU for [%d]\n", task_pid_nr(task)));
	} else {
		/*
		 * when not current, task MUST be stopped, so this is safe
		 */
		regs = task_pt_regs(task);

		/* force a full reload */
		ctx->ctx_last_activation = PFM_INVALID_ACTIVATION;
		SET_LAST_CPU(ctx, -1);

		/* initial saved psr (stopped) */
		ctx->ctx_saved_psr_up = 0UL;
		ia64_psr(regs)->up = ia64_psr(regs)->pp = 0;
	}

	ret = 0;

error_unres:
	if (ret) pfm_unreserve_session(ctx, ctx->ctx_fl_system, the_cpu);
error:
	/*
	 * we must undo the dbregs setting (for system-wide)
	 */
	if (ret && set_dbregs) {
		LOCK_PFS(flags);
		pfm_sessions.pfs_sys_use_dbregs--;
		UNLOCK_PFS(flags);
	}
	/*
	 * release task, there is now a link with the context
	 */
	if (is_system == 0 && task != current) {
		pfm_put_task(task);

		if (ret == 0) {
			ret = pfm_check_task_exist(ctx);
			if (ret) {
				ctx->ctx_state = PFM_CTX_UNLOADED;
				ctx->ctx_task  = NULL;
			}
		}
	}
	return ret;
}

/*
 * in this function, we do not need to increase the use count
 * for the task via get_task_struct(), because we hold the
 * context lock. If the task were to disappear while having
 * a context attached, it would go through pfm_exit_thread()
 * which also grabs the context lock  and would therefore be blocked
 * until we are here.
 */
static void pfm_flush_pmds(struct task_struct *, pfm_context_t *ctx);

static int
pfm_context_unload(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
{
	struct task_struct *task = PFM_CTX_TASK(ctx);
	struct pt_regs *tregs;
	int prev_state, is_system;
	int ret;

	DPRINT(("ctx_state=%d task [%d]\n", ctx->ctx_state, task ? task_pid_nr(task) : -1));

	prev_state = ctx->ctx_state;
	is_system  = ctx->ctx_fl_system;

	/*
	 * unload only when necessary
	 */
	if (prev_state == PFM_CTX_UNLOADED) {
		DPRINT(("ctx_state=%d, nothing to do\n", prev_state));
		return 0;
	}

	/*
	 * clear psr and dcr bits
	 */
	ret = pfm_stop(ctx, NULL, 0, regs);
	if (ret) return ret;

	ctx->ctx_state = PFM_CTX_UNLOADED;

	/*
	 * in system mode, we need to update the PMU directly
	 * and the user level state of the caller, which may not
	 * necessarily be the creator of the context.
	 */
	if (is_system) {

		/*
		 * Update cpuinfo
		 *
		 * local PMU is taken care of in pfm_stop()
		 */
		PFM_CPUINFO_CLEAR(PFM_CPUINFO_SYST_WIDE);
		PFM_CPUINFO_CLEAR(PFM_CPUINFO_EXCL_IDLE);

		/*
		 * save PMDs in context
		 * release ownership
		 */
		pfm_flush_pmds(current, ctx);

		/*
		 * at this point we are done with the PMU
		 * so we can unreserve the resource.
		 */
		if (prev_state != PFM_CTX_ZOMBIE) 
			pfm_unreserve_session(ctx, 1 , ctx->ctx_cpu);

		/*
		 * disconnect context from task
		 */
		task->thread.pfm_context = NULL;
		/*
		 * disconnect task from context
		 */
		ctx->ctx_task = NULL;

		/*
		 * There is nothing more to cleanup here.
		 */
		return 0;
	}

	/*
	 * per-task mode
	 */
	tregs = task == current ? regs : task_pt_regs(task);

	if (task == current) {
		/*
		 * cancel user level control
		 */
		ia64_psr(regs)->sp = 1;

		DPRINT(("setting psr.sp for [%d]\n", task_pid_nr(task)));
	}
	/*
	 * save PMDs to context
	 * release ownership
	 */
	pfm_flush_pmds(task, ctx);

	/*
	 * at this point we are done with the PMU
	 * so we can unreserve the resource.
	 *
	 * when state was ZOMBIE, we have already unreserved.
	 */
	if (prev_state != PFM_CTX_ZOMBIE) 
		pfm_unreserve_session(ctx, 0 , ctx->ctx_cpu);

	/*
	 * reset activation counter and psr
	 */
	ctx->ctx_last_activation = PFM_INVALID_ACTIVATION;
	SET_LAST_CPU(ctx, -1);

	/*
	 * PMU state will not be restored
	 */
	task->thread.flags &= ~IA64_THREAD_PM_VALID;

	/*
	 * break links between context and task
	 */
	task->thread.pfm_context  = NULL;
	ctx->ctx_task             = NULL;

	PFM_SET_WORK_PENDING(task, 0);

	ctx->ctx_fl_trap_reason  = PFM_TRAP_REASON_NONE;
	ctx->ctx_fl_can_restart  = 0;
	ctx->ctx_fl_going_zombie = 0;

	DPRINT(("disconnected [%d] from context\n", task_pid_nr(task)));

	return 0;
}


/*
 * called only from exit_thread(): task == current
 * we come here only if current has a context attached (loaded or masked)
 */
void
pfm_exit_thread(struct task_struct *task)
{
	pfm_context_t *ctx;
	unsigned long flags;
	struct pt_regs *regs = task_pt_regs(task);
	int ret, state;
	int free_ok = 0;

	ctx = PFM_GET_CTX(task);

	PROTECT_CTX(ctx, flags);

	DPRINT(("state=%d task [%d]\n", ctx->ctx_state, task_pid_nr(task)));

	state = ctx->ctx_state;
	switch(state) {
		case PFM_CTX_UNLOADED:
			/*
	 		 * only comes to this function if pfm_context is not NULL, i.e., cannot
			 * be in unloaded state
	 		 */
			printk(KERN_ERR "perfmon: pfm_exit_thread [%d] ctx unloaded\n", task_pid_nr(task));
			break;
		case PFM_CTX_LOADED:
		case PFM_CTX_MASKED:
			ret = pfm_context_unload(ctx, NULL, 0, regs);
			if (ret) {
				printk(KERN_ERR "perfmon: pfm_exit_thread [%d] state=%d unload failed %d\n", task_pid_nr(task), state, ret);
			}
			DPRINT(("ctx unloaded for current state was %d\n", state));

			pfm_end_notify_user(ctx);
			break;
		case PFM_CTX_ZOMBIE:
			ret = pfm_context_unload(ctx, NULL, 0, regs);
			if (ret) {
				printk(KERN_ERR "perfmon: pfm_exit_thread [%d] state=%d unload failed %d\n", task_pid_nr(task), state, ret);
			}
			free_ok = 1;
			break;
		default:
			printk(KERN_ERR "perfmon: pfm_exit_thread [%d] unexpected state=%d\n", task_pid_nr(task), state);
			break;
	}
	UNPROTECT_CTX(ctx, flags);

	{ u64 psr = pfm_get_psr();
	  BUG_ON(psr & (IA64_PSR_UP|IA64_PSR_PP));
	  BUG_ON(GET_PMU_OWNER());
	  BUG_ON(ia64_psr(regs)->up);
	  BUG_ON(ia64_psr(regs)->pp);
	}

	/*
	 * All memory free operations (especially for vmalloc'ed memory)
	 * MUST be done with interrupts ENABLED.
	 */
	if (free_ok) pfm_context_free(ctx);
}

/*
 * functions MUST be listed in the increasing order of their index (see permfon.h)
 */
#define PFM_CMD(name, flags, arg_count, arg_type, getsz) { name, #name, flags, arg_count, sizeof(arg_type), getsz }
#define PFM_CMD_S(name, flags) { name, #name, flags, 0, 0, NULL }
#define PFM_CMD_PCLRWS	(PFM_CMD_FD|PFM_CMD_ARG_RW|PFM_CMD_STOP)
#define PFM_CMD_PCLRW	(PFM_CMD_FD|PFM_CMD_ARG_RW)
#define PFM_CMD_NONE	{ NULL, "no-cmd", 0, 0, 0, NULL}

static pfm_cmd_desc_t pfm_cmd_tab[]={
/* 0  */PFM_CMD_NONE,
/* 1  */PFM_CMD(pfm_write_pmcs, PFM_CMD_PCLRWS, PFM_CMD_ARG_MANY, pfarg_reg_t, NULL),
/* 2  */PFM_CMD(pfm_write_pmds, PFM_CMD_PCLRWS, PFM_CMD_ARG_MANY, pfarg_reg_t, NULL),
/* 3  */PFM_CMD(pfm_read_pmds, PFM_CMD_PCLRWS, PFM_CMD_ARG_MANY, pfarg_reg_t, NULL),
/* 4  */PFM_CMD_S(pfm_stop, PFM_CMD_PCLRWS),
/* 5  */PFM_CMD_S(pfm_start, PFM_CMD_PCLRWS),
/* 6  */PFM_CMD_NONE,
/* 7  */PFM_CMD_NONE,
/* 8  */PFM_CMD(pfm_context_create, PFM_CMD_ARG_RW, 1, pfarg_context_t, pfm_ctx_getsize),
/* 9  */PFM_CMD_NONE,
/* 10 */PFM_CMD_S(pfm_restart, PFM_CMD_PCLRW),
/* 11 */PFM_CMD_NONE,
/* 12 */PFM_CMD(pfm_get_features, PFM_CMD_ARG_RW, 1, pfarg_features_t, NULL),
/* 13 */PFM_CMD(pfm_debug, 0, 1, unsigned int, NULL),
/* 14 */PFM_CMD_NONE,
/* 15 */PFM_CMD(pfm_get_pmc_reset, PFM_CMD_ARG_RW, PFM_CMD_ARG_MANY, pfarg_reg_t, NULL),
/* 16 */PFM_CMD(pfm_context_load, PFM_CMD_PCLRWS, 1, pfarg_load_t, NULL),
/* 17 */PFM_CMD_S(pfm_context_unload, PFM_CMD_PCLRWS),
/* 18 */PFM_CMD_NONE,
/* 19 */PFM_CMD_NONE,
/* 20 */PFM_CMD_NONE,
/* 21 */PFM_CMD_NONE,
/* 22 */PFM_CMD_NONE,
/* 23 */PFM_CMD_NONE,
/* 24 */PFM_CMD_NONE,
/* 25 */PFM_CMD_NONE,
/* 26 */PFM_CMD_NONE,
/* 27 */PFM_CMD_NONE,
/* 28 */PFM_CMD_NONE,
/* 29 */PFM_CMD_NONE,
/* 30 */PFM_CMD_NONE,
/* 31 */PFM_CMD_NONE,
/* 32 */PFM_CMD(pfm_write_ibrs, PFM_CMD_PCLRWS, PFM_CMD_ARG_MANY, pfarg_dbreg_t, NULL),
/* 33 */PFM_CMD(pfm_write_dbrs, PFM_CMD_PCLRWS, PFM_CMD_ARG_MANY, pfarg_dbreg_t, NULL)
};
#define PFM_CMD_COUNT	(sizeof(pfm_cmd_tab)/sizeof(pfm_cmd_desc_t))

static int
pfm_check_task_state(pfm_context_t *ctx, int cmd, unsigned long flags)
{
	struct task_struct *task;
	int state, old_state;

recheck:
	state = ctx->ctx_state;
	task  = ctx->ctx_task;

	if (task == NULL) {
		DPRINT(("context %d no task, state=%d\n", ctx->ctx_fd, state));
		return 0;
	}

	DPRINT(("context %d state=%d [%d] task_state=%ld must_stop=%d\n",
		ctx->ctx_fd,
		state,
		task_pid_nr(task),
		task->state, PFM_CMD_STOPPED(cmd)));

	/*
	 * self-monitoring always ok.
	 *
	 * for system-wide the caller can either be the creator of the
	 * context (to one to which the context is attached to) OR
	 * a task running on the same CPU as the session.
	 */
	if (task == current || ctx->ctx_fl_system) return 0;

	/*
	 * we are monitoring another thread
	 */
	switch(state) {
		case PFM_CTX_UNLOADED:
			/*
			 * if context is UNLOADED we are safe to go
			 */
			return 0;
		case PFM_CTX_ZOMBIE:
			/*
			 * no command can operate on a zombie context
			 */
			DPRINT(("cmd %d state zombie cannot operate on context\n", cmd));
			return -EINVAL;
		case PFM_CTX_MASKED:
			/*
			 * PMU state has been saved to software even though
			 * the thread may still be running.
			 */
			if (cmd != PFM_UNLOAD_CONTEXT) return 0;
	}

	/*
	 * context is LOADED or MASKED. Some commands may need to have 
	 * the task stopped.
	 *
	 * We could lift this restriction for UP but it would mean that
	 * the user has no guarantee the task would not run between
	 * two successive calls to perfmonctl(). That's probably OK.
	 * If this user wants to ensure the task does not run, then
	 * the task must be stopped.
	 */
	if (PFM_CMD_STOPPED(cmd)) {
		if (!task_is_stopped_or_traced(task)) {
			DPRINT(("[%d] task not in stopped state\n", task_pid_nr(task)));
			return -EBUSY;
		}
		/*
		 * task is now stopped, wait for ctxsw out
		 *
		 * This is an interesting point in the code.
		 * We need to unprotect the context because
		 * the pfm_save_regs() routines needs to grab
		 * the same lock. There are danger in doing
		 * this because it leaves a window open for
		 * another task to get access to the context
		 * and possibly change its state. The one thing
		 * that is not possible is for the context to disappear
		 * because we are protected by the VFS layer, i.e.,
		 * get_fd()/put_fd().
		 */
		old_state = state;

		UNPROTECT_CTX(ctx, flags);

		wait_task_inactive(task, 0);

		PROTECT_CTX(ctx, flags);

		/*
		 * we must recheck to verify if state has changed
		 */
		if (ctx->ctx_state != old_state) {
			DPRINT(("old_state=%d new_state=%d\n", old_state, ctx->ctx_state));
			goto recheck;
		}
	}
	return 0;
}

/*
 * system-call entry point (must return long)
 */
asmlinkage long
sys_perfmonctl (int fd, int cmd, void __user *arg, int count)
{
	struct file *file = NULL;
	pfm_context_t *ctx = NULL;
	unsigned long flags = 0UL;
	void *args_k = NULL;
	long ret; /* will expand int return types */
	size_t base_sz, sz, xtra_sz = 0;
	int narg, completed_args = 0, call_made = 0, cmd_flags;
	int (*func)(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs);
	int (*getsize)(void *arg, size_t *sz);
#define PFM_MAX_ARGSIZE	4096

	/*
	 * reject any call if perfmon was disabled at initialization
	 */
	if (unlikely(pmu_conf == NULL)) return -ENOSYS;

	if (unlikely(cmd < 0 || cmd >= PFM_CMD_COUNT)) {
		DPRINT(("invalid cmd=%d\n", cmd));
		return -EINVAL;
	}

	func      = pfm_cmd_tab[cmd].cmd_func;
	narg      = pfm_cmd_tab[cmd].cmd_narg;
	base_sz   = pfm_cmd_tab[cmd].cmd_argsize;
	getsize   = pfm_cmd_tab[cmd].cmd_getsize;
	cmd_flags = pfm_cmd_tab[cmd].cmd_flags;

	if (unlikely(func == NULL)) {
		DPRINT(("invalid cmd=%d\n", cmd));
		return -EINVAL;
	}

	DPRINT(("cmd=%s idx=%d narg=0x%x argsz=%lu count=%d\n",
		PFM_CMD_NAME(cmd),
		cmd,
		narg,
		base_sz,
		count));

	/*
	 * check if number of arguments matches what the command expects
	 */
	if (unlikely((narg == PFM_CMD_ARG_MANY && count <= 0) || (narg > 0 && narg != count)))
		return -EINVAL;

restart_args:
	sz = xtra_sz + base_sz*count;
	/*
	 * limit abuse to min page size
	 */
	if (unlikely(sz > PFM_MAX_ARGSIZE)) {
		printk(KERN_ERR "perfmon: [%d] argument too big %lu\n", task_pid_nr(current), sz);
		return -E2BIG;
	}

	/*
	 * allocate default-sized argument buffer
	 */
	if (likely(count && args_k == NULL)) {
		args_k = kmalloc(PFM_MAX_ARGSIZE, GFP_KERNEL);
		if (args_k == NULL) return -ENOMEM;
	}

	ret = -EFAULT;

	/*
	 * copy arguments
	 *
	 * assume sz = 0 for command without parameters
	 */
	if (sz && copy_from_user(args_k, arg, sz)) {
		DPRINT(("cannot copy_from_user %lu bytes @%p\n", sz, arg));
		goto error_args;
	}

	/*
	 * check if command supports extra parameters
	 */
	if (completed_args == 0 && getsize) {
		/*
		 * get extra parameters size (based on main argument)
		 */
		ret = (*getsize)(args_k, &xtra_sz);
		if (ret) goto error_args;

		completed_args = 1;

		DPRINT(("restart_args sz=%lu xtra_sz=%lu\n", sz, xtra_sz));

		/* retry if necessary */
		if (likely(xtra_sz)) goto restart_args;
	}

	if (unlikely((cmd_flags & PFM_CMD_FD) == 0)) goto skip_fd;

	ret = -EBADF;

	file = fget(fd);
	if (unlikely(file == NULL)) {
		DPRINT(("invalid fd %d\n", fd));
		goto error_args;
	}
	if (unlikely(PFM_IS_FILE(file) == 0)) {
		DPRINT(("fd %d not related to perfmon\n", fd));
		goto error_args;
	}

	ctx = (pfm_context_t *)file->private_data;
	if (unlikely(ctx == NULL)) {
		DPRINT(("no context for fd %d\n", fd));
		goto error_args;
	}
	prefetch(&ctx->ctx_state);

	PROTECT_CTX(ctx, flags);

	/*
	 * check task is stopped
	 */
	ret = pfm_check_task_state(ctx, cmd, flags);
	if (unlikely(ret)) goto abort_locked;

skip_fd:
	ret = (*func)(ctx, args_k, count, task_pt_regs(current));

	call_made = 1;

abort_locked:
	if (likely(ctx)) {
		DPRINT(("context unlocked\n"));
		UNPROTECT_CTX(ctx, flags);
	}

	/* copy argument back to user, if needed */
	if (call_made && PFM_CMD_RW_ARG(cmd) && copy_to_user(arg, args_k, base_sz*count)) ret = -EFAULT;

error_args:
	if (file)
		fput(file);

	kfree(args_k);

	DPRINT(("cmd=%s ret=%ld\n", PFM_CMD_NAME(cmd), ret));

	return ret;
}

static void
pfm_resume_after_ovfl(pfm_context_t *ctx, unsigned long ovfl_regs, struct pt_regs *regs)
{
	pfm_buffer_fmt_t *fmt = ctx->ctx_buf_fmt;
	pfm_ovfl_ctrl_t rst_ctrl;
	int state;
	int ret = 0;

	state = ctx->ctx_state;
	/*
	 * Unlock sampling buffer and reset index atomically
	 * XXX: not really needed when blocking
	 */
	if (CTX_HAS_SMPL(ctx)) {

		rst_ctrl.bits.mask_monitoring = 0;
		rst_ctrl.bits.reset_ovfl_pmds = 0;

		if (state == PFM_CTX_LOADED)
			ret = pfm_buf_fmt_restart_active(fmt, current, &rst_ctrl, ctx->ctx_smpl_hdr, regs);
		else
			ret = pfm_buf_fmt_restart(fmt, current, &rst_ctrl, ctx->ctx_smpl_hdr, regs);
	} else {
		rst_ctrl.bits.mask_monitoring = 0;
		rst_ctrl.bits.reset_ovfl_pmds = 1;
	}

	if (ret == 0) {
		if (rst_ctrl.bits.reset_ovfl_pmds) {
			pfm_reset_regs(ctx, &ovfl_regs, PFM_PMD_LONG_RESET);
		}
		if (rst_ctrl.bits.mask_monitoring == 0) {
			DPRINT(("resuming monitoring\n"));
			if (ctx->ctx_state == PFM_CTX_MASKED) pfm_restore_monitoring(current);
		} else {
			DPRINT(("stopping monitoring\n"));
			//pfm_stop_monitoring(current, regs);
		}
		ctx->ctx_state = PFM_CTX_LOADED;
	}
}

/*
 * context MUST BE LOCKED when calling
 * can only be called for current
 */
static void
pfm_context_force_terminate(pfm_context_t *ctx, struct pt_regs *regs)
{
	int ret;

	DPRINT(("entering for [%d]\n", task_pid_nr(current)));

	ret = pfm_context_unload(ctx, NULL, 0, regs);
	if (ret) {
		printk(KERN_ERR "pfm_context_force_terminate: [%d] unloaded failed with %d\n", task_pid_nr(current), ret);
	}

	/*
	 * and wakeup controlling task, indicating we are now disconnected
	 */
	wake_up_interruptible(&ctx->ctx_zombieq);

	/*
	 * given that context is still locked, the controlling
	 * task will only get access when we return from
	 * pfm_handle_work().
	 */
}

static int pfm_ovfl_notify_user(pfm_context_t *ctx, unsigned long ovfl_pmds);

 /*
  * pfm_handle_work() can be called with interrupts enabled
  * (TIF_NEED_RESCHED) or disabled. The down_interruptible
  * call may sleep, therefore we must re-enable interrupts
  * to avoid deadlocks. It is safe to do so because this function
  * is called ONLY when returning to user level (pUStk=1), in which case
  * there is no risk of kernel stack overflow due to deep
  * interrupt nesting.
  */
void
pfm_handle_work(void)
{
	pfm_context_t *ctx;
	struct pt_regs *regs;
	unsigned long flags, dummy_flags;
	unsigned long ovfl_regs;
	unsigned int reason;
	int ret;

	ctx = PFM_GET_CTX(current);
	if (ctx == NULL) {
		printk(KERN_ERR "perfmon: [%d] has no PFM context\n",
			task_pid_nr(current));
		return;
	}

	PROTECT_CTX(ctx, flags);

	PFM_SET_WORK_PENDING(current, 0);

	regs = task_pt_regs(current);

	/*
	 * extract reason for being here and clear
	 */
	reason = ctx->ctx_fl_trap_reason;
	ctx->ctx_fl_trap_reason = PFM_TRAP_REASON_NONE;
	ovfl_regs = ctx->ctx_ovfl_regs[0];

	DPRINT(("reason=%d state=%d\n", reason, ctx->ctx_state));

	/*
	 * must be done before we check for simple-reset mode
	 */
	if (ctx->ctx_fl_going_zombie || ctx->ctx_state == PFM_CTX_ZOMBIE)
		goto do_zombie;

	//if (CTX_OVFL_NOBLOCK(ctx)) goto skip_blocking;
	if (reason == PFM_TRAP_REASON_RESET)
		goto skip_blocking;

	/*
	 * restore interrupt mask to what it was on entry.
	 * Could be enabled/diasbled.
	 */
	UNPROTECT_CTX(ctx, flags);

	/*
	 * force interrupt enable because of down_interruptible()
	 */
	local_irq_enable();

	DPRINT(("before block sleeping\n"));

	/*
	 * may go through without blocking on SMP systems
	 * if restart has been received already by the time we call down()
	 */
	ret = wait_for_completion_interruptible(&ctx->ctx_restart_done);

	DPRINT(("after block sleeping ret=%d\n", ret));

	/*
	 * lock context and mask interrupts again
	 * We save flags into a dummy because we may have
	 * altered interrupts mask compared to entry in this
	 * function.
	 */
	PROTECT_CTX(ctx, dummy_flags);

	/*
	 * we need to read the ovfl_regs only after wake-up
	 * because we may have had pfm_write_pmds() in between
	 * and that can changed PMD values and therefore 
	 * ovfl_regs is reset for these new PMD values.
	 */
	ovfl_regs = ctx->ctx_ovfl_regs[0];

	if (ctx->ctx_fl_going_zombie) {
do_zombie:
		DPRINT(("context is zombie, bailing out\n"));
		pfm_context_force_terminate(ctx, regs);
		goto nothing_to_do;
	}
	/*
	 * in case of interruption of down() we don't restart anything
	 */
	if (ret < 0)
		goto nothing_to_do;

skip_blocking:
	pfm_resume_after_ovfl(ctx, ovfl_regs, regs);
	ctx->ctx_ovfl_regs[0] = 0UL;

nothing_to_do:
	/*
	 * restore flags as they were upon entry
	 */
	UNPROTECT_CTX(ctx, flags);
}

static int
pfm_notify_user(pfm_context_t *ctx, pfm_msg_t *msg)
{
	if (ctx->ctx_state == PFM_CTX_ZOMBIE) {
		DPRINT(("ignoring overflow notification, owner is zombie\n"));
		return 0;
	}

	DPRINT(("waking up somebody\n"));

	if (msg) wake_up_interruptible(&ctx->ctx_msgq_wait);

	/*
	 * safe, we are not in intr handler, nor in ctxsw when
	 * we come here
	 */
	kill_fasync (&ctx->ctx_async_queue, SIGIO, POLL_IN);

	return 0;
}

static int
pfm_ovfl_notify_user(pfm_context_t *ctx, unsigned long ovfl_pmds)
{
	pfm_msg_t *msg = NULL;

	if (ctx->ctx_fl_no_msg == 0) {
		msg = pfm_get_new_msg(ctx);
		if (msg == NULL) {
			printk(KERN_ERR "perfmon: pfm_ovfl_notify_user no more notification msgs\n");
			return -1;
		}

		msg->pfm_ovfl_msg.msg_type         = PFM_MSG_OVFL;
		msg->pfm_ovfl_msg.msg_ctx_fd       = ctx->ctx_fd;
		msg->pfm_ovfl_msg.msg_active_set   = 0;
		msg->pfm_ovfl_msg.msg_ovfl_pmds[0] = ovfl_pmds;
		msg->pfm_ovfl_msg.msg_ovfl_pmds[1] = 0UL;
		msg->pfm_ovfl_msg.msg_ovfl_pmds[2] = 0UL;
		msg->pfm_ovfl_msg.msg_ovfl_pmds[3] = 0UL;
		msg->pfm_ovfl_msg.msg_tstamp       = 0UL;
	}

	DPRINT(("ovfl msg: msg=%p no_msg=%d fd=%d ovfl_pmds=0x%lx\n",
		msg,
		ctx->ctx_fl_no_msg,
		ctx->ctx_fd,
		ovfl_pmds));

	return pfm_notify_user(ctx, msg);
}

static int
pfm_end_notify_user(pfm_context_t *ctx)
{
	pfm_msg_t *msg;

	msg = pfm_get_new_msg(ctx);
	if (msg == NULL) {
		printk(KERN_ERR "perfmon: pfm_end_notify_user no more notification msgs\n");
		return -1;
	}
	/* no leak */
	memset(msg, 0, sizeof(*msg));

	msg->pfm_end_msg.msg_type    = PFM_MSG_END;
	msg->pfm_end_msg.msg_ctx_fd  = ctx->ctx_fd;
	msg->pfm_ovfl_msg.msg_tstamp = 0UL;

	DPRINT(("end msg: msg=%p no_msg=%d ctx_fd=%d\n",
		msg,
		ctx->ctx_fl_no_msg,
		ctx->ctx_fd));

	return pfm_notify_user(ctx, msg);
}

/*
 * main overflow processing routine.
 * it can be called from the interrupt path or explicitly during the context switch code
 */
static void pfm_overflow_handler(struct task_struct *task, pfm_context_t *ctx,
				unsigned long pmc0, struct pt_regs *regs)
{
	pfm_ovfl_arg_t *ovfl_arg;
	unsigned long mask;
	unsigned long old_val, ovfl_val, new_val;
	unsigned long ovfl_notify = 0UL, ovfl_pmds = 0UL, smpl_pmds = 0UL, reset_pmds;
	unsigned long tstamp;
	pfm_ovfl_ctrl_t	ovfl_ctrl;
	unsigned int i, has_smpl;
	int must_notify = 0;

	if (unlikely(ctx->ctx_state == PFM_CTX_ZOMBIE)) goto stop_monitoring;

	/*
	 * sanity test. Should never happen
	 */
	if (unlikely((pmc0 & 0x1) == 0)) goto sanity_check;

	tstamp   = ia64_get_itc();
	mask     = pmc0 >> PMU_FIRST_COUNTER;
	ovfl_val = pmu_conf->ovfl_val;
	has_smpl = CTX_HAS_SMPL(ctx);

	DPRINT_ovfl(("pmc0=0x%lx pid=%d iip=0x%lx, %s "
		     "used_pmds=0x%lx\n",
			pmc0,
			task ? task_pid_nr(task): -1,
			(regs ? regs->cr_iip : 0),
			CTX_OVFL_NOBLOCK(ctx) ? "nonblocking" : "blocking",
			ctx->ctx_used_pmds[0]));


	/*
	 * first we update the virtual counters
	 * assume there was a prior ia64_srlz_d() issued
	 */
	for (i = PMU_FIRST_COUNTER; mask ; i++, mask >>= 1) {

		/* skip pmd which did not overflow */
		if ((mask & 0x1) == 0) continue;

		/*
		 * Note that the pmd is not necessarily 0 at this point as qualified events
		 * may have happened before the PMU was frozen. The residual count is not
		 * taken into consideration here but will be with any read of the pmd via
		 * pfm_read_pmds().
		 */
		old_val              = new_val = ctx->ctx_pmds[i].val;
		new_val             += 1 + ovfl_val;
		ctx->ctx_pmds[i].val = new_val;

		/*
		 * check for overflow condition
		 */
		if (likely(old_val > new_val)) {
			ovfl_pmds |= 1UL << i;
			if (PMC_OVFL_NOTIFY(ctx, i)) ovfl_notify |= 1UL << i;
		}

		DPRINT_ovfl(("ctx_pmd[%d].val=0x%lx old_val=0x%lx pmd=0x%lx ovfl_pmds=0x%lx ovfl_notify=0x%lx\n",
			i,
			new_val,
			old_val,
			ia64_get_pmd(i) & ovfl_val,
			ovfl_pmds,
			ovfl_notify));
	}

	/*
	 * there was no 64-bit overflow, nothing else to do
	 */
	if (ovfl_pmds == 0UL) return;

	/* 
	 * reset all control bits
	 */
	ovfl_ctrl.val = 0;
	reset_pmds    = 0UL;

	/*
	 * if a sampling format module exists, then we "cache" the overflow by 
	 * calling the module's handler() routine.
	 */
	if (has_smpl) {
		unsigned long start_cycles, end_cycles;
		unsigned long pmd_mask;
		int j, k, ret = 0;
		int this_cpu = smp_processor_id();

		pmd_mask = ovfl_pmds >> PMU_FIRST_COUNTER;
		ovfl_arg = &ctx->ctx_ovfl_arg;

		prefetch(ctx->ctx_smpl_hdr);

		for(i=PMU_FIRST_COUNTER; pmd_mask && ret == 0; i++, pmd_mask >>=1) {

			mask = 1UL << i;

			if ((pmd_mask & 0x1) == 0) continue;

			ovfl_arg->ovfl_pmd      = (unsigned char )i;
			ovfl_arg->ovfl_notify   = ovfl_notify & mask ? 1 : 0;
			ovfl_arg->active_set    = 0;
			ovfl_arg->ovfl_ctrl.val = 0; /* module must fill in all fields */
			ovfl_arg->smpl_pmds[0]  = smpl_pmds = ctx->ctx_pmds[i].smpl_pmds[0];

			ovfl_arg->pmd_value      = ctx->ctx_pmds[i].val;
			ovfl_arg->pmd_last_reset = ctx->ctx_pmds[i].lval;
			ovfl_arg->pmd_eventid    = ctx->ctx_pmds[i].eventid;

			/*
		 	 * copy values of pmds of interest. Sampling format may copy them
		 	 * into sampling buffer.
		 	 */
			if (smpl_pmds) {
				for(j=0, k=0; smpl_pmds; j++, smpl_pmds >>=1) {
					if ((smpl_pmds & 0x1) == 0) continue;
					ovfl_arg->smpl_pmds_values[k++] = PMD_IS_COUNTING(j) ?  pfm_read_soft_counter(ctx, j) : ia64_get_pmd(j);
					DPRINT_ovfl(("smpl_pmd[%d]=pmd%u=0x%lx\n", k-1, j, ovfl_arg->smpl_pmds_values[k-1]));
				}
			}

			pfm_stats[this_cpu].pfm_smpl_handler_calls++;

			start_cycles = ia64_get_itc();

			/*
		 	 * call custom buffer format record (handler) routine
		 	 */
			ret = (*ctx->ctx_buf_fmt->fmt_handler)(task, ctx->ctx_smpl_hdr, ovfl_arg, regs, tstamp);

			end_cycles = ia64_get_itc();

			/*
			 * For those controls, we take the union because they have
			 * an all or nothing behavior.
			 */
			ovfl_ctrl.bits.notify_user     |= ovfl_arg->ovfl_ctrl.bits.notify_user;
			ovfl_ctrl.bits.block_task      |= ovfl_arg->ovfl_ctrl.bits.block_task;
			ovfl_ctrl.bits.mask_monitoring |= ovfl_arg->ovfl_ctrl.bits.mask_monitoring;
			/*
			 * build the bitmask of pmds to reset now
			 */
			if (ovfl_arg->ovfl_ctrl.bits.reset_ovfl_pmds) reset_pmds |= mask;

			pfm_stats[this_cpu].pfm_smpl_handler_cycles += end_cycles - start_cycles;
		}
		/*
		 * when the module cannot handle the rest of the overflows, we abort right here
		 */
		if (ret && pmd_mask) {
			DPRINT(("handler aborts leftover ovfl_pmds=0x%lx\n",
				pmd_mask<<PMU_FIRST_COUNTER));
		}
		/*
		 * remove the pmds we reset now from the set of pmds to reset in pfm_restart()
		 */
		ovfl_pmds &= ~reset_pmds;
	} else {
		/*
		 * when no sampling module is used, then the default
		 * is to notify on overflow if requested by user
		 */
		ovfl_ctrl.bits.notify_user     = ovfl_notify ? 1 : 0;
		ovfl_ctrl.bits.block_task      = ovfl_notify ? 1 : 0;
		ovfl_ctrl.bits.mask_monitoring = ovfl_notify ? 1 : 0; /* XXX: change for saturation */
		ovfl_ctrl.bits.reset_ovfl_pmds = ovfl_notify ? 0 : 1;
		/*
		 * if needed, we reset all overflowed pmds
		 */
		if (ovfl_notify == 0) reset_pmds = ovfl_pmds;
	}

	DPRINT_ovfl(("ovfl_pmds=0x%lx reset_pmds=0x%lx\n", ovfl_pmds, reset_pmds));

	/*
	 * reset the requested PMD registers using the short reset values
	 */
	if (reset_pmds) {
		unsigned long bm = reset_pmds;
		pfm_reset_regs(ctx, &bm, PFM_PMD_SHORT_RESET);
	}

	if (ovfl_notify && ovfl_ctrl.bits.notify_user) {
		/*
		 * keep track of what to reset when unblocking
		 */
		ctx->ctx_ovfl_regs[0] = ovfl_pmds;

		/*
		 * check for blocking context 
		 */
		if (CTX_OVFL_NOBLOCK(ctx) == 0 && ovfl_ctrl.bits.block_task) {

			ctx->ctx_fl_trap_reason = PFM_TRAP_REASON_BLOCK;

			/*
			 * set the perfmon specific checking pending work for the task
			 */
			PFM_SET_WORK_PENDING(task, 1);

			/*
			 * when coming from ctxsw, current still points to the
			 * previous task, therefore we must work with task and not current.
			 */
			set_notify_resume(task);
		}
		/*
		 * defer until state is changed (shorten spin window). the context is locked
		 * anyway, so the signal receiver would come spin for nothing.
		 */
		must_notify = 1;
	}

	DPRINT_ovfl(("owner [%d] pending=%ld reason=%u ovfl_pmds=0x%lx ovfl_notify=0x%lx masked=%d\n",
			GET_PMU_OWNER() ? task_pid_nr(GET_PMU_OWNER()) : -1,
			PFM_GET_WORK_PENDING(task),
			ctx->ctx_fl_trap_reason,
			ovfl_pmds,
			ovfl_notify,
			ovfl_ctrl.bits.mask_monitoring ? 1 : 0));
	/*
	 * in case monitoring must be stopped, we toggle the psr bits
	 */
	if (ovfl_ctrl.bits.mask_monitoring) {
		pfm_mask_monitoring(task);
		ctx->ctx_state = PFM_CTX_MASKED;
		ctx->ctx_fl_can_restart = 1;
	}

	/*
	 * send notification now
	 */
	if (must_notify) pfm_ovfl_notify_user(ctx, ovfl_notify);

	return;

sanity_check:
	printk(KERN_ERR "perfmon: CPU%d overflow handler [%d] pmc0=0x%lx\n",
			smp_processor_id(),
			task ? task_pid_nr(task) : -1,
			pmc0);
	return;

stop_monitoring:
	/*
	 * in SMP, zombie context is never restored but reclaimed in pfm_load_regs().
	 * Moreover, zombies are also reclaimed in pfm_save_regs(). Therefore we can
	 * come here as zombie only if the task is the current task. In which case, we
	 * can access the PMU  hardware directly.
	 *
	 * Note that zombies do have PM_VALID set. So here we do the minimal.
	 *
	 * In case the context was zombified it could not be reclaimed at the time
	 * the monitoring program exited. At this point, the PMU reservation has been
	 * returned, the sampiing buffer has been freed. We must convert this call
	 * into a spurious interrupt. However, we must also avoid infinite overflows
	 * by stopping monitoring for this task. We can only come here for a per-task
	 * context. All we need to do is to stop monitoring using the psr bits which
	 * are always task private. By re-enabling secure montioring, we ensure that
	 * the monitored task will not be able to re-activate monitoring.
	 * The task will eventually be context switched out, at which point the context
	 * will be reclaimed (that includes releasing ownership of the PMU).
	 *
	 * So there might be a window of time where the number of per-task session is zero
	 * yet one PMU might have a owner and get at most one overflow interrupt for a zombie
	 * context. This is safe because if a per-task session comes in, it will push this one
	 * out and by the virtue on pfm_save_regs(), this one will disappear. If a system wide
	 * session is force on that CPU, given that we use task pinning, pfm_save_regs() will
	 * also push our zombie context out.
	 *
	 * Overall pretty hairy stuff....
	 */
	DPRINT(("ctx is zombie for [%d], converted to spurious\n", task ? task_pid_nr(task): -1));
	pfm_clear_psr_up();
	ia64_psr(regs)->up = 0;
	ia64_psr(regs)->sp = 1;
	return;
}

static int
pfm_do_interrupt_handler(void *arg, struct pt_regs *regs)
{
	struct task_struct *task;
	pfm_context_t *ctx;
	unsigned long flags;
	u64 pmc0;
	int this_cpu = smp_processor_id();
	int retval = 0;

	pfm_stats[this_cpu].pfm_ovfl_intr_count++;

	/*
	 * srlz.d done before arriving here
	 */
	pmc0 = ia64_get_pmc(0);

	task = GET_PMU_OWNER();
	ctx  = GET_PMU_CTX();

	/*
	 * if we have some pending bits set
	 * assumes : if any PMC0.bit[63-1] is set, then PMC0.fr = 1
	 */
	if (PMC0_HAS_OVFL(pmc0) && task) {
		/*
		 * we assume that pmc0.fr is always set here
		 */

		/* sanity check */
		if (!ctx) goto report_spurious1;

		if (ctx->ctx_fl_system == 0 && (task->thread.flags & IA64_THREAD_PM_VALID) == 0) 
			goto report_spurious2;

		PROTECT_CTX_NOPRINT(ctx, flags);

		pfm_overflow_handler(task, ctx, pmc0, regs);

		UNPROTECT_CTX_NOPRINT(ctx, flags);

	} else {
		pfm_stats[this_cpu].pfm_spurious_ovfl_intr_count++;
		retval = -1;
	}
	/*
	 * keep it unfrozen at all times
	 */
	pfm_unfreeze_pmu();

	return retval;

report_spurious1:
	printk(KERN_INFO "perfmon: spurious overflow interrupt on CPU%d: process %d has no PFM context\n",
		this_cpu, task_pid_nr(task));
	pfm_unfreeze_pmu();
	return -1;
report_spurious2:
	printk(KERN_INFO "perfmon: spurious overflow interrupt on CPU%d: process %d, invalid flag\n", 
		this_cpu, 
		task_pid_nr(task));
	pfm_unfreeze_pmu();
	return -1;
}

static irqreturn_t
pfm_interrupt_handler(int irq, void *arg)
{
	unsigned long start_cycles, total_cycles;
	unsigned long min, max;
	int this_cpu;
	int ret;
	struct pt_regs *regs = get_irq_regs();

	this_cpu = get_cpu();
	if (likely(!pfm_alt_intr_handler)) {
		min = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min;
		max = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max;

		start_cycles = ia64_get_itc();

		ret = pfm_do_interrupt_handler(arg, regs);

		total_cycles = ia64_get_itc();

		/*
		 * don't measure spurious interrupts
		 */
		if (likely(ret == 0)) {
			total_cycles -= start_cycles;

			if (total_cycles < min) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min = total_cycles;
			if (total_cycles > max) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max = total_cycles;

			pfm_stats[this_cpu].pfm_ovfl_intr_cycles += total_cycles;
		}
	}
	else {
		(*pfm_alt_intr_handler->handler)(irq, arg, regs);
	}

	put_cpu();
	return IRQ_HANDLED;
}

/*
 * /proc/perfmon interface, for debug only
 */

#define PFM_PROC_SHOW_HEADER	((void *)(long)nr_cpu_ids+1)

static void *
pfm_proc_start(struct seq_file *m, loff_t *pos)
{
	if (*pos == 0) {
		return PFM_PROC_SHOW_HEADER;
	}

	while (*pos <= nr_cpu_ids) {
		if (cpu_online(*pos - 1)) {
			return (void *)*pos;
		}
		++*pos;
	}
	return NULL;
}

static void *
pfm_proc_next(struct seq_file *m, void *v, loff_t *pos)
{
	++*pos;
	return pfm_proc_start(m, pos);
}

static void
pfm_proc_stop(struct seq_file *m, void *v)
{
}

static void
pfm_proc_show_header(struct seq_file *m)
{
	struct list_head * pos;
	pfm_buffer_fmt_t * entry;
	unsigned long flags;

 	seq_printf(m,
		"perfmon version           : %u.%u\n"
		"model                     : %s\n"
		"fastctxsw                 : %s\n"
		"expert mode               : %s\n"
		"ovfl_mask                 : 0x%lx\n"
		"PMU flags                 : 0x%x\n",
		PFM_VERSION_MAJ, PFM_VERSION_MIN,
		pmu_conf->pmu_name,
		pfm_sysctl.fastctxsw > 0 ? "Yes": "No",
		pfm_sysctl.expert_mode > 0 ? "Yes": "No",
		pmu_conf->ovfl_val,
		pmu_conf->flags);

  	LOCK_PFS(flags);

 	seq_printf(m,
 		"proc_sessions             : %u\n"
 		"sys_sessions              : %u\n"
 		"sys_use_dbregs            : %u\n"
 		"ptrace_use_dbregs         : %u\n",
 		pfm_sessions.pfs_task_sessions,
 		pfm_sessions.pfs_sys_sessions,
 		pfm_sessions.pfs_sys_use_dbregs,
 		pfm_sessions.pfs_ptrace_use_dbregs);

  	UNLOCK_PFS(flags);

	spin_lock(&pfm_buffer_fmt_lock);

	list_for_each(pos, &pfm_buffer_fmt_list) {
		entry = list_entry(pos, pfm_buffer_fmt_t, fmt_list);
		seq_printf(m, "format                    : %02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x %s\n",
			entry->fmt_uuid[0],
			entry->fmt_uuid[1],
			entry->fmt_uuid[2],
			entry->fmt_uuid[3],
			entry->fmt_uuid[4],
			entry->fmt_uuid[5],
			entry->fmt_uuid[6],
			entry->fmt_uuid[7],
			entry->fmt_uuid[8],
			entry->fmt_uuid[9],
			entry->fmt_uuid[10],
			entry->fmt_uuid[11],
			entry->fmt_uuid[12],
			entry->fmt_uuid[13],
			entry->fmt_uuid[14],
			entry->fmt_uuid[15],
			entry->fmt_name);
	}
	spin_unlock(&pfm_buffer_fmt_lock);

}

static int
pfm_proc_show(struct seq_file *m, void *v)
{
	unsigned long psr;
	unsigned int i;
	int cpu;

	if (v == PFM_PROC_SHOW_HEADER) {
		pfm_proc_show_header(m);
		return 0;
	}

	/* show info for CPU (v - 1) */

	cpu = (long)v - 1;
	seq_printf(m,
		"CPU%-2d overflow intrs      : %lu\n"
		"CPU%-2d overflow cycles     : %lu\n"
		"CPU%-2d overflow min        : %lu\n"
		"CPU%-2d overflow max        : %lu\n"
		"CPU%-2d smpl handler calls  : %lu\n"
		"CPU%-2d smpl handler cycles : %lu\n"
		"CPU%-2d spurious intrs      : %lu\n"
		"CPU%-2d replay   intrs      : %lu\n"
		"CPU%-2d syst_wide           : %d\n"
		"CPU%-2d dcr_pp              : %d\n"
		"CPU%-2d exclude idle        : %d\n"
		"CPU%-2d owner               : %d\n"
		"CPU%-2d context             : %p\n"
		"CPU%-2d activations         : %lu\n",
		cpu, pfm_stats[cpu].pfm_ovfl_intr_count,
		cpu, pfm_stats[cpu].pfm_ovfl_intr_cycles,
		cpu, pfm_stats[cpu].pfm_ovfl_intr_cycles_min,
		cpu, pfm_stats[cpu].pfm_ovfl_intr_cycles_max,
		cpu, pfm_stats[cpu].pfm_smpl_handler_calls,
		cpu, pfm_stats[cpu].pfm_smpl_handler_cycles,
		cpu, pfm_stats[cpu].pfm_spurious_ovfl_intr_count,
		cpu, pfm_stats[cpu].pfm_replay_ovfl_intr_count,
		cpu, pfm_get_cpu_data(pfm_syst_info, cpu) & PFM_CPUINFO_SYST_WIDE ? 1 : 0,
		cpu, pfm_get_cpu_data(pfm_syst_info, cpu) & PFM_CPUINFO_DCR_PP ? 1 : 0,
		cpu, pfm_get_cpu_data(pfm_syst_info, cpu) & PFM_CPUINFO_EXCL_IDLE ? 1 : 0,
		cpu, pfm_get_cpu_data(pmu_owner, cpu) ? pfm_get_cpu_data(pmu_owner, cpu)->pid: -1,
		cpu, pfm_get_cpu_data(pmu_ctx, cpu),
		cpu, pfm_get_cpu_data(pmu_activation_number, cpu));

	if (num_online_cpus() == 1 && pfm_sysctl.debug > 0) {

		psr = pfm_get_psr();

		ia64_srlz_d();

		seq_printf(m, 
			"CPU%-2d psr                 : 0x%lx\n"
			"CPU%-2d pmc0                : 0x%lx\n", 
			cpu, psr,
			cpu, ia64_get_pmc(0));

		for (i=0; PMC_IS_LAST(i) == 0;  i++) {
			if (PMC_IS_COUNTING(i) == 0) continue;
   			seq_printf(m, 
				"CPU%-2d pmc%u                : 0x%lx\n"
   				"CPU%-2d pmd%u                : 0x%lx\n", 
				cpu, i, ia64_get_pmc(i),
				cpu, i, ia64_get_pmd(i));
  		}
	}
	return 0;
}

const struct seq_operations pfm_seq_ops = {
	.start =	pfm_proc_start,
 	.next =		pfm_proc_next,
 	.stop =		pfm_proc_stop,
 	.show =		pfm_proc_show
};

static int
pfm_proc_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &pfm_seq_ops);
}


/*
 * we come here as soon as local_cpu_data->pfm_syst_wide is set. this happens
 * during pfm_enable() hence before pfm_start(). We cannot assume monitoring
 * is active or inactive based on mode. We must rely on the value in
 * local_cpu_data->pfm_syst_info
 */
void
pfm_syst_wide_update_task(struct task_struct *task, unsigned long info, int is_ctxswin)
{
	struct pt_regs *regs;
	unsigned long dcr;
	unsigned long dcr_pp;

	dcr_pp = info & PFM_CPUINFO_DCR_PP ? 1 : 0;

	/*
	 * pid 0 is guaranteed to be the idle task. There is one such task with pid 0
	 * on every CPU, so we can rely on the pid to identify the idle task.
	 */
	if ((info & PFM_CPUINFO_EXCL_IDLE) == 0 || task->pid) {
		regs = task_pt_regs(task);
		ia64_psr(regs)->pp = is_ctxswin ? dcr_pp : 0;
		return;
	}
	/*
	 * if monitoring has started
	 */
	if (dcr_pp) {
		dcr = ia64_getreg(_IA64_REG_CR_DCR);
		/*
		 * context switching in?
		 */
		if (is_ctxswin) {
			/* mask monitoring for the idle task */
			ia64_setreg(_IA64_REG_CR_DCR, dcr & ~IA64_DCR_PP);
			pfm_clear_psr_pp();
			ia64_srlz_i();
			return;
		}
		/*
		 * context switching out
		 * restore monitoring for next task
		 *
		 * Due to inlining this odd if-then-else construction generates
		 * better code.
		 */
		ia64_setreg(_IA64_REG_CR_DCR, dcr |IA64_DCR_PP);
		pfm_set_psr_pp();
		ia64_srlz_i();
	}
}

#ifdef CONFIG_SMP

static void
pfm_force_cleanup(pfm_context_t *ctx, struct pt_regs *regs)
{
	struct task_struct *task = ctx->ctx_task;

	ia64_psr(regs)->up = 0;
	ia64_psr(regs)->sp = 1;

	if (GET_PMU_OWNER() == task) {
		DPRINT(("cleared ownership for [%d]\n",
					task_pid_nr(ctx->ctx_task)));
		SET_PMU_OWNER(NULL, NULL);
	}

	/*
	 * disconnect the task from the context and vice-versa
	 */
	PFM_SET_WORK_PENDING(task, 0);

	task->thread.pfm_context  = NULL;
	task->thread.flags       &= ~IA64_THREAD_PM_VALID;

	DPRINT(("force cleanup for [%d]\n",  task_pid_nr(task)));
}


/*
 * in 2.6, interrupts are masked when we come here and the runqueue lock is held
 */
void
pfm_save_regs(struct task_struct *task)
{
	pfm_context_t *ctx;
	unsigned long flags;
	u64 psr;


	ctx = PFM_GET_CTX(task);
	if (ctx == NULL) return;

	/*
 	 * we always come here with interrupts ALREADY disabled by
 	 * the scheduler. So we simply need to protect against concurrent
	 * access, not CPU concurrency.
	 */
	flags = pfm_protect_ctx_ctxsw(ctx);

	if (ctx->ctx_state == PFM_CTX_ZOMBIE) {
		struct pt_regs *regs = task_pt_regs(task);

		pfm_clear_psr_up();

		pfm_force_cleanup(ctx, regs);

		BUG_ON(ctx->ctx_smpl_hdr);

		pfm_unprotect_ctx_ctxsw(ctx, flags);

		pfm_context_free(ctx);
		return;
	}

	/*
	 * save current PSR: needed because we modify it
	 */
	ia64_srlz_d();
	psr = pfm_get_psr();

	BUG_ON(psr & (IA64_PSR_I));

	/*
	 * stop monitoring:
	 * This is the last instruction which may generate an overflow
	 *
	 * We do not need to set psr.sp because, it is irrelevant in kernel.
	 * It will be restored from ipsr when going back to user level
	 */
	pfm_clear_psr_up();

	/*
	 * keep a copy of psr.up (for reload)
	 */
	ctx->ctx_saved_psr_up = psr & IA64_PSR_UP;

	/*
	 * release ownership of this PMU.
	 * PM interrupts are masked, so nothing
	 * can happen.
	 */
	SET_PMU_OWNER(NULL, NULL);

	/*
	 * we systematically save the PMD as we have no
	 * guarantee we will be schedule at that same
	 * CPU again.
	 */
	pfm_save_pmds(ctx->th_pmds, ctx->ctx_used_pmds[0]);

	/*
	 * save pmc0 ia64_srlz_d() done in pfm_save_pmds()
	 * we will need it on the restore path to check
	 * for pending overflow.
	 */
	ctx->th_pmcs[0] = ia64_get_pmc(0);

	/*
	 * unfreeze PMU if had pending overflows
	 */
	if (ctx->th_pmcs[0] & ~0x1UL) pfm_unfreeze_pmu();

	/*
	 * finally, allow context access.
	 * interrupts will still be masked after this call.
	 */
	pfm_unprotect_ctx_ctxsw(ctx, flags);
}

#else /* !CONFIG_SMP */
void
pfm_save_regs(struct task_struct *task)
{
	pfm_context_t *ctx;
	u64 psr;

	ctx = PFM_GET_CTX(task);
	if (ctx == NULL) return;

	/*
	 * save current PSR: needed because we modify it
	 */
	psr = pfm_get_psr();

	BUG_ON(psr & (IA64_PSR_I));

	/*
	 * stop monitoring:
	 * This is the last instruction which may generate an overflow
	 *
	 * We do not need to set psr.sp because, it is irrelevant in kernel.
	 * It will be restored from ipsr when going back to user level
	 */
	pfm_clear_psr_up();

	/*
	 * keep a copy of psr.up (for reload)
	 */
	ctx->ctx_saved_psr_up = psr & IA64_PSR_UP;
}

static void
pfm_lazy_save_regs (struct task_struct *task)
{
	pfm_context_t *ctx;
	unsigned long flags;

	{ u64 psr  = pfm_get_psr();
	  BUG_ON(psr & IA64_PSR_UP);
	}

	ctx = PFM_GET_CTX(task);

	/*
	 * we need to mask PMU overflow here to
	 * make sure that we maintain pmc0 until
	 * we save it. overflow interrupts are
	 * treated as spurious if there is no
	 * owner.
	 *
	 * XXX: I don't think this is necessary
	 */
	PROTECT_CTX(ctx,flags);

	/*
	 * release ownership of this PMU.
	 * must be done before we save the registers.
	 *
	 * after this call any PMU interrupt is treated
	 * as spurious.
	 */
	SET_PMU_OWNER(NULL, NULL);

	/*
	 * save all the pmds we use
	 */
	pfm_save_pmds(ctx->th_pmds, ctx->ctx_used_pmds[0]);

	/*
	 * save pmc0 ia64_srlz_d() done in pfm_save_pmds()
	 * it is needed to check for pended overflow
	 * on the restore path
	 */
	ctx->th_pmcs[0] = ia64_get_pmc(0);

	/*
	 * unfreeze PMU if had pending overflows
	 */
	if (ctx->th_pmcs[0] & ~0x1UL) pfm_unfreeze_pmu();

	/*
	 * now get can unmask PMU interrupts, they will
	 * be treated as purely spurious and we will not
	 * lose any information
	 */
	UNPROTECT_CTX(ctx,flags);
}
#endif /* CONFIG_SMP */

#ifdef CONFIG_SMP
/*
 * in 2.6, interrupts are masked when we come here and the runqueue lock is held
 */
void
pfm_load_regs (struct task_struct *task)
{
	pfm_context_t *ctx;
	unsigned long pmc_mask = 0UL, pmd_mask = 0UL;
	unsigned long flags;
	u64 psr, psr_up;
	int need_irq_resend;

	ctx = PFM_GET_CTX(task);
	if (unlikely(ctx == NULL)) return;

	BUG_ON(GET_PMU_OWNER());

	/*
	 * possible on unload
	 */
	if (unlikely((task->thread.flags & IA64_THREAD_PM_VALID) == 0)) return;

	/*
 	 * we always come here with interrupts ALREADY disabled by
 	 * the scheduler. So we simply need to protect against concurrent
	 * access, not CPU concurrency.
	 */
	flags = pfm_protect_ctx_ctxsw(ctx);
	psr   = pfm_get_psr();

	need_irq_resend = pmu_conf->flags & PFM_PMU_IRQ_RESEND;

	BUG_ON(psr & (IA64_PSR_UP|IA64_PSR_PP));
	BUG_ON(psr & IA64_PSR_I);

	if (unlikely(ctx->ctx_state == PFM_CTX_ZOMBIE)) {
		struct pt_regs *regs = task_pt_regs(task);

		BUG_ON(ctx->ctx_smpl_hdr);

		pfm_force_cleanup(ctx, regs);

		pfm_unprotect_ctx_ctxsw(ctx, flags);

		/*
		 * this one (kmalloc'ed) is fine with interrupts disabled
		 */
		pfm_context_free(ctx);

		return;
	}

	/*
	 * we restore ALL the debug registers to avoid picking up
	 * stale state.
	 */
	if (ctx->ctx_fl_using_dbreg) {
		pfm_restore_ibrs(ctx->ctx_ibrs, pmu_conf->num_ibrs);
		pfm_restore_dbrs(ctx->ctx_dbrs, pmu_conf->num_dbrs);
	}
	/*
	 * retrieve saved psr.up
	 */
	psr_up = ctx->ctx_saved_psr_up;

	/*
	 * if we were the last user of the PMU on that CPU,
	 * then nothing to do except restore psr
	 */
	if (GET_LAST_CPU(ctx) == smp_processor_id() && ctx->ctx_last_activation == GET_ACTIVATION()) {

		/*
		 * retrieve partial reload masks (due to user modifications)
		 */
		pmc_mask = ctx->ctx_reload_pmcs[0];
		pmd_mask = ctx->ctx_reload_pmds[0];

	} else {
		/*
	 	 * To avoid leaking information to the user level when psr.sp=0,
	 	 * we must reload ALL implemented pmds (even the ones we don't use).
	 	 * In the kernel we only allow PFM_READ_PMDS on registers which
	 	 * we initialized or requested (sampling) so there is no risk there.
	 	 */
		pmd_mask = pfm_sysctl.fastctxsw ?  ctx->ctx_used_pmds[0] : ctx->ctx_all_pmds[0];

		/*
	 	 * ALL accessible PMCs are systematically reloaded, unused registers
	 	 * get their default (from pfm_reset_pmu_state()) values to avoid picking
	 	 * up stale configuration.
	 	 *
	 	 * PMC0 is never in the mask. It is always restored separately.
	 	 */
		pmc_mask = ctx->ctx_all_pmcs[0];
	}
	/*
	 * when context is MASKED, we will restore PMC with plm=0
	 * and PMD with stale information, but that's ok, nothing
	 * will be captured.
	 *
	 * XXX: optimize here
	 */
	if (pmd_mask) pfm_restore_pmds(ctx->th_pmds, pmd_mask);
	if (pmc_mask) pfm_restore_pmcs(ctx->th_pmcs, pmc_mask);

	/*
	 * check for pending overflow at the time the state
	 * was saved.
	 */
	if (unlikely(PMC0_HAS_OVFL(ctx->th_pmcs[0]))) {
		/*
		 * reload pmc0 with the overflow information
		 * On McKinley PMU, this will trigger a PMU interrupt
		 */
		ia64_set_pmc(0, ctx->th_pmcs[0]);
		ia64_srlz_d();
		ctx->th_pmcs[0] = 0UL;

		/*
		 * will replay the PMU interrupt
		 */
		if (need_irq_resend) ia64_resend_irq(IA64_PERFMON_VECTOR);

		pfm_stats[smp_processor_id()].pfm_replay_ovfl_intr_count++;
	}

	/*
	 * we just did a reload, so we reset the partial reload fields
	 */
	ctx->ctx_reload_pmcs[0] = 0UL;
	ctx->ctx_reload_pmds[0] = 0UL;

	SET_LAST_CPU(ctx, smp_processor_id());

	/*
	 * dump activation value for this PMU
	 */
	INC_ACTIVATION();
	/*
	 * record current activation for this context
	 */
	SET_ACTIVATION(ctx);

	/*
	 * establish new ownership. 
	 */
	SET_PMU_OWNER(task, ctx);

	/*
	 * restore the psr.up bit. measurement
	 * is active again.
	 * no PMU interrupt can happen at this point
	 * because we still have interrupts disabled.
	 */
	if (likely(psr_up)) pfm_set_psr_up();

	/*
	 * allow concurrent access to context
	 */
	pfm_unprotect_ctx_ctxsw(ctx, flags);
}
#else /*  !CONFIG_SMP */
/*
 * reload PMU state for UP kernels
 * in 2.5 we come here with interrupts disabled
 */
void
pfm_load_regs (struct task_struct *task)
{
	pfm_context_t *ctx;
	struct task_struct *owner;
	unsigned long pmd_mask, pmc_mask;
	u64 psr, psr_up;
	int need_irq_resend;

	owner = GET_PMU_OWNER();
	ctx   = PFM_GET_CTX(task);
	psr   = pfm_get_psr();

	BUG_ON(psr & (IA64_PSR_UP|IA64_PSR_PP));
	BUG_ON(psr & IA64_PSR_I);

	/*
	 * we restore ALL the debug registers to avoid picking up
	 * stale state.
	 *
	 * This must be done even when the task is still the owner
	 * as the registers may have been modified via ptrace()
	 * (not perfmon) by the previous task.
	 */
	if (ctx->ctx_fl_using_dbreg) {
		pfm_restore_ibrs(ctx->ctx_ibrs, pmu_conf->num_ibrs);
		pfm_restore_dbrs(ctx->ctx_dbrs, pmu_conf->num_dbrs);
	}

	/*
	 * retrieved saved psr.up
	 */
	psr_up = ctx->ctx_saved_psr_up;
	need_irq_resend = pmu_conf->flags & PFM_PMU_IRQ_RESEND;

	/*
	 * short path, our state is still there, just
	 * need to restore psr and we go
	 *
	 * we do not touch either PMC nor PMD. the psr is not touched
	 * by the overflow_handler. So we are safe w.r.t. to interrupt
	 * concurrency even without interrupt masking.
	 */
	if (likely(owner == task)) {
		if (likely(psr_up)) pfm_set_psr_up();
		return;
	}

	/*
	 * someone else is still using the PMU, first push it out and
	 * then we'll be able to install our stuff !
	 *
	 * Upon return, there will be no owner for the current PMU
	 */
	if (owner) pfm_lazy_save_regs(owner);

	/*
	 * To avoid leaking information to the user level when psr.sp=0,
	 * we must reload ALL implemented pmds (even the ones we don't use).
	 * In the kernel we only allow PFM_READ_PMDS on registers which
	 * we initialized or requested (sampling) so there is no risk there.
	 */
	pmd_mask = pfm_sysctl.fastctxsw ?  ctx->ctx_used_pmds[0] : ctx->ctx_all_pmds[0];

	/*
	 * ALL accessible PMCs are systematically reloaded, unused registers
	 * get their default (from pfm_reset_pmu_state()) values to avoid picking
	 * up stale configuration.
	 *
	 * PMC0 is never in the mask. It is always restored separately
	 */
	pmc_mask = ctx->ctx_all_pmcs[0];

	pfm_restore_pmds(ctx->th_pmds, pmd_mask);
	pfm_restore_pmcs(ctx->th_pmcs, pmc_mask);

	/*
	 * check for pending overflow at the time the state
	 * was saved.
	 */
	if (unlikely(PMC0_HAS_OVFL(ctx->th_pmcs[0]))) {
		/*
		 * reload pmc0 with the overflow information
		 * On McKinley PMU, this will trigger a PMU interrupt
		 */
		ia64_set_pmc(0, ctx->th_pmcs[0]);
		ia64_srlz_d();

		ctx->th_pmcs[0] = 0UL;

		/*
		 * will replay the PMU interrupt
		 */
		if (need_irq_resend) ia64_resend_irq(IA64_PERFMON_VECTOR);

		pfm_stats[smp_processor_id()].pfm_replay_ovfl_intr_count++;
	}

	/*
	 * establish new ownership. 
	 */
	SET_PMU_OWNER(task, ctx);

	/*
	 * restore the psr.up bit. measurement
	 * is active again.
	 * no PMU interrupt can happen at this point
	 * because we still have interrupts disabled.
	 */
	if (likely(psr_up)) pfm_set_psr_up();
}
#endif /* CONFIG_SMP */

/*
 * this function assumes monitoring is stopped
 */
static void
pfm_flush_pmds(struct task_struct *task, pfm_context_t *ctx)
{
	u64 pmc0;
	unsigned long mask2, val, pmd_val, ovfl_val;
	int i, can_access_pmu = 0;
	int is_self;

	/*
	 * is the caller the task being monitored (or which initiated the
	 * session for system wide measurements)
	 */
	is_self = ctx->ctx_task == task ? 1 : 0;

	/*
	 * can access PMU is task is the owner of the PMU state on the current CPU
	 * or if we are running on the CPU bound to the context in system-wide mode
	 * (that is not necessarily the task the context is attached to in this mode).
	 * In system-wide we always have can_access_pmu true because a task running on an
	 * invalid processor is flagged earlier in the call stack (see pfm_stop).
	 */
	can_access_pmu = (GET_PMU_OWNER() == task) || (ctx->ctx_fl_system && ctx->ctx_cpu == smp_processor_id());
	if (can_access_pmu) {
		/*
		 * Mark the PMU as not owned
		 * This will cause the interrupt handler to do nothing in case an overflow
		 * interrupt was in-flight
		 * This also guarantees that pmc0 will contain the final state
		 * It virtually gives us full control on overflow processing from that point
		 * on.
		 */
		SET_PMU_OWNER(NULL, NULL);
		DPRINT(("releasing ownership\n"));

		/*
		 * read current overflow status:
		 *
		 * we are guaranteed to read the final stable state
		 */
		ia64_srlz_d();
		pmc0 = ia64_get_pmc(0); /* slow */

		/*
		 * reset freeze bit, overflow status information destroyed
		 */
		pfm_unfreeze_pmu();
	} else {
		pmc0 = ctx->th_pmcs[0];
		/*
		 * clear whatever overflow status bits there were
		 */
		ctx->th_pmcs[0] = 0;
	}
	ovfl_val = pmu_conf->ovfl_val;
	/*
	 * we save all the used pmds
	 * we take care of overflows for counting PMDs
	 *
	 * XXX: sampling situation is not taken into account here
	 */
	mask2 = ctx->ctx_used_pmds[0];

	DPRINT(("is_self=%d ovfl_val=0x%lx mask2=0x%lx\n", is_self, ovfl_val, mask2));

	for (i = 0; mask2; i++, mask2>>=1) {

		/* skip non used pmds */
		if ((mask2 & 0x1) == 0) continue;

		/*
		 * can access PMU always true in system wide mode
		 */
		val = pmd_val = can_access_pmu ? ia64_get_pmd(i) : ctx->th_pmds[i];

		if (PMD_IS_COUNTING(i)) {
			DPRINT(("[%d] pmd[%d] ctx_pmd=0x%lx hw_pmd=0x%lx\n",
				task_pid_nr(task),
				i,
				ctx->ctx_pmds[i].val,
				val & ovfl_val));

			/*
			 * we rebuild the full 64 bit value of the counter
			 */
			val = ctx->ctx_pmds[i].val + (val & ovfl_val);

			/*
			 * now everything is in ctx_pmds[] and we need
			 * to clear the saved context from save_regs() such that
			 * pfm_read_pmds() gets the correct value
			 */
			pmd_val = 0UL;

			/*
			 * take care of overflow inline
			 */
			if (pmc0 & (1UL << i)) {
				val += 1 + ovfl_val;
				DPRINT(("[%d] pmd[%d] overflowed\n", task_pid_nr(task), i));
			}
		}

		DPRINT(("[%d] ctx_pmd[%d]=0x%lx  pmd_val=0x%lx\n", task_pid_nr(task), i, val, pmd_val));

		if (is_self) ctx->th_pmds[i] = pmd_val;

		ctx->ctx_pmds[i].val = val;
	}
}

static struct irqaction perfmon_irqaction = {
	.handler = pfm_interrupt_handler,
	.flags   = IRQF_DISABLED,
	.name    = "perfmon"
};

static void
pfm_alt_save_pmu_state(void *data)
{
	struct pt_regs *regs;

	regs = task_pt_regs(current);

	DPRINT(("called\n"));

	/*
	 * should not be necessary but
	 * let's take not risk
	 */
	pfm_clear_psr_up();
	pfm_clear_psr_pp();
	ia64_psr(regs)->pp = 0;

	/*
	 * This call is required
	 * May cause a spurious interrupt on some processors
	 */
	pfm_freeze_pmu();

	ia64_srlz_d();
}

void
pfm_alt_restore_pmu_state(void *data)
{
	struct pt_regs *regs;

	regs = task_pt_regs(current);

	DPRINT(("called\n"));

	/*
	 * put PMU back in state expected
	 * by perfmon
	 */
	pfm_clear_psr_up();
	pfm_clear_psr_pp();
	ia64_psr(regs)->pp = 0;

	/*
	 * perfmon runs with PMU unfrozen at all times
	 */
	pfm_unfreeze_pmu();

	ia64_srlz_d();
}

int
pfm_install_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
{
	int ret, i;
	int reserve_cpu;

	/* some sanity checks */
	if (hdl == NULL || hdl->handler == NULL) return -EINVAL;

	/* do the easy test first */
	if (pfm_alt_intr_handler) return -EBUSY;

	/* one at a time in the install or remove, just fail the others */
	if (!spin_trylock(&pfm_alt_install_check)) {
		return -EBUSY;
	}

	/* reserve our session */
	for_each_online_cpu(reserve_cpu) {
		ret = pfm_reserve_session(NULL, 1, reserve_cpu);
		if (ret) goto cleanup_reserve;
	}

	/* save the current system wide pmu states */
	ret = on_each_cpu(pfm_alt_save_pmu_state, NULL, 1);
	if (ret) {
		DPRINT(("on_each_cpu() failed: %d\n", ret));
		goto cleanup_reserve;
	}

	/* officially change to the alternate interrupt handler */
	pfm_alt_intr_handler = hdl;

	spin_unlock(&pfm_alt_install_check);

	return 0;

cleanup_reserve:
	for_each_online_cpu(i) {
		/* don't unreserve more than we reserved */
		if (i >= reserve_cpu) break;

		pfm_unreserve_session(NULL, 1, i);
	}

	spin_unlock(&pfm_alt_install_check);

	return ret;
}
EXPORT_SYMBOL_GPL(pfm_install_alt_pmu_interrupt);

int
pfm_remove_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
{
	int i;
	int ret;

	if (hdl == NULL) return -EINVAL;

	/* cannot remove someone else's handler! */
	if (pfm_alt_intr_handler != hdl) return -EINVAL;

	/* one at a time in the install or remove, just fail the others */
	if (!spin_trylock(&pfm_alt_install_check)) {
		return -EBUSY;
	}

	pfm_alt_intr_handler = NULL;

	ret = on_each_cpu(pfm_alt_restore_pmu_state, NULL, 1);
	if (ret) {
		DPRINT(("on_each_cpu() failed: %d\n", ret));
	}

	for_each_online_cpu(i) {
		pfm_unreserve_session(NULL, 1, i);
	}

	spin_unlock(&pfm_alt_install_check);

	return 0;
}
EXPORT_SYMBOL_GPL(pfm_remove_alt_pmu_interrupt);

/*
 * perfmon initialization routine, called from the initcall() table
 */
static int init_pfm_fs(void);

static int __init
pfm_probe_pmu(void)
{
	pmu_config_t **p;
	int family;

	family = local_cpu_data->family;
	p      = pmu_confs;

	while(*p) {
		if ((*p)->probe) {
			if ((*p)->probe() == 0) goto found;
		} else if ((*p)->pmu_family == family || (*p)->pmu_family == 0xff) {
			goto found;
		}
		p++;
	}
	return -1;
found:
	pmu_conf = *p;
	return 0;
}

static const struct file_operations pfm_proc_fops = {
	.open		= pfm_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

int __init
pfm_init(void)
{
	unsigned int n, n_counters, i;

	printk("perfmon: version %u.%u IRQ %u\n",
		PFM_VERSION_MAJ,
		PFM_VERSION_MIN,
		IA64_PERFMON_VECTOR);

	if (pfm_probe_pmu()) {
		printk(KERN_INFO "perfmon: disabled, there is no support for processor family %d\n", 
				local_cpu_data->family);
		return -ENODEV;
	}

	/*
	 * compute the number of implemented PMD/PMC from the
	 * description tables
	 */
	n = 0;
	for (i=0; PMC_IS_LAST(i) == 0;  i++) {
		if (PMC_IS_IMPL(i) == 0) continue;
		pmu_conf->impl_pmcs[i>>6] |= 1UL << (i&63);
		n++;
	}
	pmu_conf->num_pmcs = n;

	n = 0; n_counters = 0;
	for (i=0; PMD_IS_LAST(i) == 0;  i++) {
		if (PMD_IS_IMPL(i) == 0) continue;
		pmu_conf->impl_pmds[i>>6] |= 1UL << (i&63);
		n++;
		if (PMD_IS_COUNTING(i)) n_counters++;
	}
	pmu_conf->num_pmds      = n;
	pmu_conf->num_counters  = n_counters;

	/*
	 * sanity checks on the number of debug registers
	 */
	if (pmu_conf->use_rr_dbregs) {
		if (pmu_conf->num_ibrs > IA64_NUM_DBG_REGS) {
			printk(KERN_INFO "perfmon: unsupported number of code debug registers (%u)\n", pmu_conf->num_ibrs);
			pmu_conf = NULL;
			return -1;
		}
		if (pmu_conf->num_dbrs > IA64_NUM_DBG_REGS) {
			printk(KERN_INFO "perfmon: unsupported number of data debug registers (%u)\n", pmu_conf->num_ibrs);
			pmu_conf = NULL;
			return -1;
		}
	}

	printk("perfmon: %s PMU detected, %u PMCs, %u PMDs, %u counters (%lu bits)\n",
	       pmu_conf->pmu_name,
	       pmu_conf->num_pmcs,
	       pmu_conf->num_pmds,
	       pmu_conf->num_counters,
	       ffz(pmu_conf->ovfl_val));

	/* sanity check */
	if (pmu_conf->num_pmds >= PFM_NUM_PMD_REGS || pmu_conf->num_pmcs >= PFM_NUM_PMC_REGS) {
		printk(KERN_ERR "perfmon: not enough pmc/pmd, perfmon disabled\n");
		pmu_conf = NULL;
		return -1;
	}

	/*
	 * create /proc/perfmon (mostly for debugging purposes)
	 */
	perfmon_dir = proc_create("perfmon", S_IRUGO, NULL, &pfm_proc_fops);
	if (perfmon_dir == NULL) {
		printk(KERN_ERR "perfmon: cannot create /proc entry, perfmon disabled\n");
		pmu_conf = NULL;
		return -1;
	}

	/*
	 * create /proc/sys/kernel/perfmon (for debugging purposes)
	 */
	pfm_sysctl_header = register_sysctl_table(pfm_sysctl_root);

	/*
	 * initialize all our spinlocks
	 */
	spin_lock_init(&pfm_sessions.pfs_lock);
	spin_lock_init(&pfm_buffer_fmt_lock);

	init_pfm_fs();

	for(i=0; i < NR_CPUS; i++) pfm_stats[i].pfm_ovfl_intr_cycles_min = ~0UL;

	return 0;
}

__initcall(pfm_init);

/*
 * this function is called before pfm_init()
 */
void
pfm_init_percpu (void)
{
	static int first_time=1;
	/*
	 * make sure no measurement is active
	 * (may inherit programmed PMCs from EFI).
	 */
	pfm_clear_psr_pp();
	pfm_clear_psr_up();

	/*
	 * we run with the PMU not frozen at all times
	 */
	pfm_unfreeze_pmu();

	if (first_time) {
		register_percpu_irq(IA64_PERFMON_VECTOR, &perfmon_irqaction);
		first_time=0;
	}

	ia64_setreg(_IA64_REG_CR_PMV, IA64_PERFMON_VECTOR);
	ia64_srlz_d();
}

/*
 * used for debug purposes only
 */
void
dump_pmu_state(const char *from)
{
	struct task_struct *task;
	struct pt_regs *regs;
	pfm_context_t *ctx;
	unsigned long psr, dcr, info, flags;
	int i, this_cpu;

	local_irq_save(flags);

	this_cpu = smp_processor_id();
	regs     = task_pt_regs(current);
	info     = PFM_CPUINFO_GET();
	dcr      = ia64_getreg(_IA64_REG_CR_DCR);

	if (info == 0 && ia64_psr(regs)->pp == 0 && (dcr & IA64_DCR_PP) == 0) {
		local_irq_restore(flags);
		return;
	}

	printk("CPU%d from %s() current [%d] iip=0x%lx %s\n", 
		this_cpu, 
		from, 
		task_pid_nr(current),
		regs->cr_iip,
		current->comm);

	task = GET_PMU_OWNER();
	ctx  = GET_PMU_CTX();

	printk("->CPU%d owner [%d] ctx=%p\n", this_cpu, task ? task_pid_nr(task) : -1, ctx);

	psr = pfm_get_psr();

	printk("->CPU%d pmc0=0x%lx psr.pp=%d psr.up=%d dcr.pp=%d syst_info=0x%lx user_psr.up=%d user_psr.pp=%d\n", 
		this_cpu,
		ia64_get_pmc(0),
		psr & IA64_PSR_PP ? 1 : 0,
		psr & IA64_PSR_UP ? 1 : 0,
		dcr & IA64_DCR_PP ? 1 : 0,
		info,
		ia64_psr(regs)->up,
		ia64_psr(regs)->pp);

	ia64_psr(regs)->up = 0;
	ia64_psr(regs)->pp = 0;

	for (i=1; PMC_IS_LAST(i) == 0; i++) {
		if (PMC_IS_IMPL(i) == 0) continue;
		printk("->CPU%d pmc[%d]=0x%lx thread_pmc[%d]=0x%lx\n", this_cpu, i, ia64_get_pmc(i), i, ctx->th_pmcs[i]);
	}

	for (i=1; PMD_IS_LAST(i) == 0; i++) {
		if (PMD_IS_IMPL(i) == 0) continue;
		printk("->CPU%d pmd[%d]=0x%lx thread_pmd[%d]=0x%lx\n", this_cpu, i, ia64_get_pmd(i), i, ctx->th_pmds[i]);
	}

	if (ctx) {
		printk("->CPU%d ctx_state=%d vaddr=%p addr=%p fd=%d ctx_task=[%d] saved_psr_up=0x%lx\n",
				this_cpu,
				ctx->ctx_state,
				ctx->ctx_smpl_vaddr,
				ctx->ctx_smpl_hdr,
				ctx->ctx_msgq_head,
				ctx->ctx_msgq_tail,
				ctx->ctx_saved_psr_up);
	}
	local_irq_restore(flags);
}

/*
 * called from process.c:copy_thread(). task is new child.
 */
void
pfm_inherit(struct task_struct *task, struct pt_regs *regs)
{
	struct thread_struct *thread;

	DPRINT(("perfmon: pfm_inherit clearing state for [%d]\n", task_pid_nr(task)));

	thread = &task->thread;

	/*
	 * cut links inherited from parent (current)
	 */
	thread->pfm_context = NULL;

	PFM_SET_WORK_PENDING(task, 0);

	/*
	 * the psr bits are already set properly in copy_threads()
	 */
}
#else  /* !CONFIG_PERFMON */
asmlinkage long
sys_perfmonctl (int fd, int cmd, void *arg, int count)
{
	return -ENOSYS;
}
#endif /* CONFIG_PERFMON */