summaryrefslogtreecommitdiffstats
path: root/arch/ia64/kernel/unwind.c
blob: fe1426266b9bf3092191c83183e174e746a58684 (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
/*
 * Copyright (C) 1999-2004 Hewlett-Packard Co
 *	David Mosberger-Tang <davidm@hpl.hp.com>
 * Copyright (C) 2003 Fenghua Yu <fenghua.yu@intel.com>
 * 	- Change pt_regs_off() to make it less dependant on pt_regs structure.
 */
/*
 * This file implements call frame unwind support for the Linux
 * kernel.  Parsing and processing the unwind information is
 * time-consuming, so this implementation translates the unwind
 * descriptors into unwind scripts.  These scripts are very simple
 * (basically a sequence of assignments) and efficient to execute.
 * They are cached for later re-use.  Each script is specific for a
 * given instruction pointer address and the set of predicate values
 * that the script depends on (most unwind descriptors are
 * unconditional and scripts often do not depend on predicates at
 * all).  This code is based on the unwind conventions described in
 * the "IA-64 Software Conventions and Runtime Architecture" manual.
 *
 * SMP conventions:
 *	o updates to the global unwind data (in structure "unw") are serialized
 *	  by the unw.lock spinlock
 *	o each unwind script has its own read-write lock; a thread must acquire
 *	  a read lock before executing a script and must acquire a write lock
 *	  before modifying a script
 *	o if both the unw.lock spinlock and a script's read-write lock must be
 *	  acquired, then the read-write lock must be acquired first.
 */
#include <linux/module.h>
#include <linux/bootmem.h>
#include <linux/elf.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>

#include <asm/unwind.h>

#include <asm/delay.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/ptrace_offsets.h>
#include <asm/rse.h>
#include <asm/sections.h>
#include <asm/system.h>
#include <asm/uaccess.h>

#include "entry.h"
#include "unwind_i.h"

#define UNW_LOG_CACHE_SIZE	7	/* each unw_script is ~256 bytes in size */
#define UNW_CACHE_SIZE		(1 << UNW_LOG_CACHE_SIZE)

#define UNW_LOG_HASH_SIZE	(UNW_LOG_CACHE_SIZE + 1)
#define UNW_HASH_SIZE		(1 << UNW_LOG_HASH_SIZE)

#define UNW_STATS	0	/* WARNING: this disabled interrupts for long time-spans!! */

#ifdef UNW_DEBUG
  static unsigned int unw_debug_level = UNW_DEBUG;
#  define UNW_DEBUG_ON(n)	unw_debug_level >= n
   /* Do not code a printk level, not all debug lines end in newline */
#  define UNW_DPRINT(n, ...)  if (UNW_DEBUG_ON(n)) printk(__VA_ARGS__)
#  undef inline
#  define inline
#else /* !UNW_DEBUG */
#  define UNW_DEBUG_ON(n)  0
#  define UNW_DPRINT(n, ...)
#endif /* UNW_DEBUG */

#if UNW_STATS
# define STAT(x...)	x
#else
# define STAT(x...)
#endif

#define alloc_reg_state()	kmalloc(sizeof(struct unw_reg_state), GFP_ATOMIC)
#define free_reg_state(usr)	kfree(usr)
#define alloc_labeled_state()	kmalloc(sizeof(struct unw_labeled_state), GFP_ATOMIC)
#define free_labeled_state(usr)	kfree(usr)

typedef unsigned long unw_word;
typedef unsigned char unw_hash_index_t;

static struct {
	spinlock_t lock;			/* spinlock for unwind data */

	/* list of unwind tables (one per load-module) */
	struct unw_table *tables;

	unsigned long r0;			/* constant 0 for r0 */

	/* table of registers that prologues can save (and order in which they're saved): */
	const unsigned char save_order[8];

	/* maps a preserved register index (preg_index) to corresponding switch_stack offset: */
	unsigned short sw_off[sizeof(struct unw_frame_info) / 8];

	unsigned short lru_head;		/* index of lead-recently used script */
	unsigned short lru_tail;		/* index of most-recently used script */

	/* index into unw_frame_info for preserved register i */
	unsigned short preg_index[UNW_NUM_REGS];

	short pt_regs_offsets[32];

	/* unwind table for the kernel: */
	struct unw_table kernel_table;

	/* unwind table describing the gate page (kernel code that is mapped into user space): */
	size_t gate_table_size;
	unsigned long *gate_table;

	/* hash table that maps instruction pointer to script index: */
	unsigned short hash[UNW_HASH_SIZE];

	/* script cache: */
	struct unw_script cache[UNW_CACHE_SIZE];

# ifdef UNW_DEBUG
	const char *preg_name[UNW_NUM_REGS];
# endif
# if UNW_STATS
	struct {
		struct {
			int lookups;
			int hinted_hits;
			int normal_hits;
			int collision_chain_traversals;
		} cache;
		struct {
			unsigned long build_time;
			unsigned long run_time;
			unsigned long parse_time;
			int builds;
			int news;
			int collisions;
			int runs;
		} script;
		struct {
			unsigned long init_time;
			unsigned long unwind_time;
			int inits;
			int unwinds;
		} api;
	} stat;
# endif
} unw = {
	.tables = &unw.kernel_table,
	.lock = __SPIN_LOCK_UNLOCKED(unw.lock),
	.save_order = {
		UNW_REG_RP, UNW_REG_PFS, UNW_REG_PSP, UNW_REG_PR,
		UNW_REG_UNAT, UNW_REG_LC, UNW_REG_FPSR, UNW_REG_PRI_UNAT_GR
	},
	.preg_index = {
		offsetof(struct unw_frame_info, pri_unat_loc)/8,	/* PRI_UNAT_GR */
		offsetof(struct unw_frame_info, pri_unat_loc)/8,	/* PRI_UNAT_MEM */
		offsetof(struct unw_frame_info, bsp_loc)/8,
		offsetof(struct unw_frame_info, bspstore_loc)/8,
		offsetof(struct unw_frame_info, pfs_loc)/8,
		offsetof(struct unw_frame_info, rnat_loc)/8,
		offsetof(struct unw_frame_info, psp)/8,
		offsetof(struct unw_frame_info, rp_loc)/8,
		offsetof(struct unw_frame_info, r4)/8,
		offsetof(struct unw_frame_info, r5)/8,
		offsetof(struct unw_frame_info, r6)/8,
		offsetof(struct unw_frame_info, r7)/8,
		offsetof(struct unw_frame_info, unat_loc)/8,
		offsetof(struct unw_frame_info, pr_loc)/8,
		offsetof(struct unw_frame_info, lc_loc)/8,
		offsetof(struct unw_frame_info, fpsr_loc)/8,
		offsetof(struct unw_frame_info, b1_loc)/8,
		offsetof(struct unw_frame_info, b2_loc)/8,
		offsetof(struct unw_frame_info, b3_loc)/8,
		offsetof(struct unw_frame_info, b4_loc)/8,
		offsetof(struct unw_frame_info, b5_loc)/8,
		offsetof(struct unw_frame_info, f2_loc)/8,
		offsetof(struct unw_frame_info, f3_loc)/8,
		offsetof(struct unw_frame_info, f4_loc)/8,
		offsetof(struct unw_frame_info, f5_loc)/8,
		offsetof(struct unw_frame_info, fr_loc[16 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[17 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[18 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[19 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[20 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[21 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[22 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[23 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[24 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[25 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[26 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[27 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[28 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[29 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[30 - 16])/8,
		offsetof(struct unw_frame_info, fr_loc[31 - 16])/8,
	},
	.pt_regs_offsets = {
		[0] = -1,
		offsetof(struct pt_regs,  r1),
		offsetof(struct pt_regs,  r2),
		offsetof(struct pt_regs,  r3),
		[4] = -1, [5] = -1, [6] = -1, [7] = -1,
		offsetof(struct pt_regs,  r8),
		offsetof(struct pt_regs,  r9),
		offsetof(struct pt_regs, r10),
		offsetof(struct pt_regs, r11),
		offsetof(struct pt_regs, r12),
		offsetof(struct pt_regs, r13),
		offsetof(struct pt_regs, r14),
		offsetof(struct pt_regs, r15),
		offsetof(struct pt_regs, r16),
		offsetof(struct pt_regs, r17),
		offsetof(struct pt_regs, r18),
		offsetof(struct pt_regs, r19),
		offsetof(struct pt_regs, r20),
		offsetof(struct pt_regs, r21),
		offsetof(struct pt_regs, r22),
		offsetof(struct pt_regs, r23),
		offsetof(struct pt_regs, r24),
		offsetof(struct pt_regs, r25),
		offsetof(struct pt_regs, r26),
		offsetof(struct pt_regs, r27),
		offsetof(struct pt_regs, r28),
		offsetof(struct pt_regs, r29),
		offsetof(struct pt_regs, r30),
		offsetof(struct pt_regs, r31),
	},
	.hash = { [0 ... UNW_HASH_SIZE - 1] = -1 },
#ifdef UNW_DEBUG
	.preg_name = {
		"pri_unat_gr", "pri_unat_mem", "bsp", "bspstore", "ar.pfs", "ar.rnat", "psp", "rp",
		"r4", "r5", "r6", "r7",
		"ar.unat", "pr", "ar.lc", "ar.fpsr",
		"b1", "b2", "b3", "b4", "b5",
		"f2", "f3", "f4", "f5",
		"f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23",
		"f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31"
	}
#endif
};

static inline int
read_only (void *addr)
{
	return (unsigned long) ((char *) addr - (char *) &unw.r0) < sizeof(unw.r0);
}

/*
 * Returns offset of rREG in struct pt_regs.
 */
static inline unsigned long
pt_regs_off (unsigned long reg)
{
	short off = -1;

	if (reg < ARRAY_SIZE(unw.pt_regs_offsets))
		off = unw.pt_regs_offsets[reg];

	if (off < 0) {
		UNW_DPRINT(0, "unwind.%s: bad scratch reg r%lu\n", __FUNCTION__, reg);
		off = 0;
	}
	return (unsigned long) off;
}

static inline struct pt_regs *
get_scratch_regs (struct unw_frame_info *info)
{
	if (!info->pt) {
		/* This should not happen with valid unwind info.  */
		UNW_DPRINT(0, "unwind.%s: bad unwind info: resetting info->pt\n", __FUNCTION__);
		if (info->flags & UNW_FLAG_INTERRUPT_FRAME)
			info->pt = (unsigned long) ((struct pt_regs *) info->psp - 1);
		else
			info->pt = info->sp - 16;
	}
	UNW_DPRINT(3, "unwind.%s: sp 0x%lx pt 0x%lx\n", __FUNCTION__, info->sp, info->pt);
	return (struct pt_regs *) info->pt;
}

/* Unwind accessors.  */

int
unw_access_gr (struct unw_frame_info *info, int regnum, unsigned long *val, char *nat, int write)
{
	unsigned long *addr, *nat_addr, nat_mask = 0, dummy_nat;
	struct unw_ireg *ireg;
	struct pt_regs *pt;

	if ((unsigned) regnum - 1 >= 127) {
		if (regnum == 0 && !write) {
			*val = 0;	/* read r0 always returns 0 */
			*nat = 0;
			return 0;
		}
		UNW_DPRINT(0, "unwind.%s: trying to access non-existent r%u\n",
			   __FUNCTION__, regnum);
		return -1;
	}

	if (regnum < 32) {
		if (regnum >= 4 && regnum <= 7) {
			/* access a preserved register */
			ireg = &info->r4 + (regnum - 4);
			addr = ireg->loc;
			if (addr) {
				nat_addr = addr + ireg->nat.off;
				switch (ireg->nat.type) {
				      case UNW_NAT_VAL:
					/* simulate getf.sig/setf.sig */
					if (write) {
						if (*nat) {
							/* write NaTVal and be done with it */
							addr[0] = 0;
							addr[1] = 0x1fffe;
							return 0;
						}
						addr[1] = 0x1003e;
					} else {
						if (addr[0] == 0 && addr[1] == 0x1ffe) {
							/* return NaT and be done with it */
							*val = 0;
							*nat = 1;
							return 0;
						}
					}
					/* fall through */
				      case UNW_NAT_NONE:
					dummy_nat = 0;
					nat_addr = &dummy_nat;
					break;

				      case UNW_NAT_MEMSTK:
					nat_mask = (1UL << ((long) addr & 0x1f8)/8);
					break;

				      case UNW_NAT_REGSTK:
					nat_addr = ia64_rse_rnat_addr(addr);
					if ((unsigned long) addr < info->regstk.limit
					    || (unsigned long) addr >= info->regstk.top)
					{
						UNW_DPRINT(0, "unwind.%s: %p outside of regstk "
							"[0x%lx-0x%lx)\n",
							__FUNCTION__, (void *) addr,
							info->regstk.limit,
							info->regstk.top);
						return -1;
					}
					if ((unsigned long) nat_addr >= info->regstk.top)
						nat_addr = &info->sw->ar_rnat;
					nat_mask = (1UL << ia64_rse_slot_num(addr));
					break;
				}
			} else {
				addr = &info->sw->r4 + (regnum - 4);
				nat_addr = &info->sw->ar_unat;
				nat_mask = (1UL << ((long) addr & 0x1f8)/8);
			}
		} else {
			/* access a scratch register */
			pt = get_scratch_regs(info);
			addr = (unsigned long *) ((unsigned long)pt + pt_regs_off(regnum));
			if (info->pri_unat_loc)
				nat_addr = info->pri_unat_loc;
			else
				nat_addr = &info->sw->caller_unat;
			nat_mask = (1UL << ((long) addr & 0x1f8)/8);
		}
	} else {
		/* access a stacked register */
		addr = ia64_rse_skip_regs((unsigned long *) info->bsp, regnum - 32);
		nat_addr = ia64_rse_rnat_addr(addr);
		if ((unsigned long) addr < info->regstk.limit
		    || (unsigned long) addr >= info->regstk.top)
		{
			UNW_DPRINT(0, "unwind.%s: ignoring attempt to access register outside "
				   "of rbs\n",  __FUNCTION__);
			return -1;
		}
		if ((unsigned long) nat_addr >= info->regstk.top)
			nat_addr = &info->sw->ar_rnat;
		nat_mask = (1UL << ia64_rse_slot_num(addr));
	}

	if (write) {
		if (read_only(addr)) {
			UNW_DPRINT(0, "unwind.%s: ignoring attempt to write read-only location\n",
				__FUNCTION__);
		} else {
			*addr = *val;
			if (*nat)
				*nat_addr |= nat_mask;
			else
				*nat_addr &= ~nat_mask;
		}
	} else {
		if ((*nat_addr & nat_mask) == 0) {
			*val = *addr;
			*nat = 0;
		} else {
			*val = 0;	/* if register is a NaT, *addr may contain kernel data! */
			*nat = 1;
		}
	}
	return 0;
}
EXPORT_SYMBOL(unw_access_gr);

int
unw_access_br (struct unw_frame_info *info, int regnum, unsigned long *val, int write)
{
	unsigned long *addr;
	struct pt_regs *pt;

	switch (regnum) {
		/* scratch: */
	      case 0: pt = get_scratch_regs(info); addr = &pt->b0; break;
	      case 6: pt = get_scratch_regs(info); addr = &pt->b6; break;
	      case 7: pt = get_scratch_regs(info); addr = &pt->b7; break;

		/* preserved: */
	      case 1: case 2: case 3: case 4: case 5:
		addr = *(&info->b1_loc + (regnum - 1));
		if (!addr)
			addr = &info->sw->b1 + (regnum - 1);
		break;

	      default:
		UNW_DPRINT(0, "unwind.%s: trying to access non-existent b%u\n",
			   __FUNCTION__, regnum);
		return -1;
	}
	if (write)
		if (read_only(addr)) {
			UNW_DPRINT(0, "unwind.%s: ignoring attempt to write read-only location\n",
				__FUNCTION__);
		} else
			*addr = *val;
	else
		*val = *addr;
	return 0;
}
EXPORT_SYMBOL(unw_access_br);

int
unw_access_fr (struct unw_frame_info *info, int regnum, struct ia64_fpreg *val, int write)
{
	struct ia64_fpreg *addr = NULL;
	struct pt_regs *pt;

	if ((unsigned) (regnum - 2) >= 126) {
		UNW_DPRINT(0, "unwind.%s: trying to access non-existent f%u\n",
			   __FUNCTION__, regnum);
		return -1;
	}

	if (regnum <= 5) {
		addr = *(&info->f2_loc + (regnum - 2));
		if (!addr)
			addr = &info->sw->f2 + (regnum - 2);
	} else if (regnum <= 15) {
		if (regnum <= 11) {
			pt = get_scratch_regs(info);
			addr = &pt->f6  + (regnum - 6);
		}
		else
			addr = &info->sw->f12 + (regnum - 12);
	} else if (regnum <= 31) {
		addr = info->fr_loc[regnum - 16];
		if (!addr)
			addr = &info->sw->f16 + (regnum - 16);
	} else {
		struct task_struct *t = info->task;

		if (write)
			ia64_sync_fph(t);
		else
			ia64_flush_fph(t);
		addr = t->thread.fph + (regnum - 32);
	}

	if (write)
		if (read_only(addr)) {
			UNW_DPRINT(0, "unwind.%s: ignoring attempt to write read-only location\n",
				__FUNCTION__);
		} else
			*addr = *val;
	else
		*val = *addr;
	return 0;
}
EXPORT_SYMBOL(unw_access_fr);

int
unw_access_ar (struct unw_frame_info *info, int regnum, unsigned long *val, int write)
{
	unsigned long *addr;
	struct pt_regs *pt;

	switch (regnum) {
	      case UNW_AR_BSP:
		addr = info->bsp_loc;
		if (!addr)
			addr = &info->sw->ar_bspstore;
		break;

	      case UNW_AR_BSPSTORE:
		addr = info->bspstore_loc;
		if (!addr)
			addr = &info->sw->ar_bspstore;
		break;

	      case UNW_AR_PFS:
		addr = info->pfs_loc;
		if (!addr)
			addr = &info->sw->ar_pfs;
		break;

	      case UNW_AR_RNAT:
		addr = info->rnat_loc;
		if (!addr)
			addr = &info->sw->ar_rnat;
		break;

	      case UNW_AR_UNAT:
		addr = info->unat_loc;
		if (!addr)
			addr = &info->sw->caller_unat;
		break;

	      case UNW_AR_LC:
		addr = info->lc_loc;
		if (!addr)
			addr = &info->sw->ar_lc;
		break;

	      case UNW_AR_EC:
		if (!info->cfm_loc)
			return -1;
		if (write)
			*info->cfm_loc =
				(*info->cfm_loc & ~(0x3fUL << 52)) | ((*val & 0x3f) << 52);
		else
			*val = (*info->cfm_loc >> 52) & 0x3f;
		return 0;

	      case UNW_AR_FPSR:
		addr = info->fpsr_loc;
		if (!addr)
			addr = &info->sw->ar_fpsr;
		break;

	      case UNW_AR_RSC:
		pt = get_scratch_regs(info);
		addr = &pt->ar_rsc;
		break;

	      case UNW_AR_CCV:
		pt = get_scratch_regs(info);
		addr = &pt->ar_ccv;
		break;

	      case UNW_AR_CSD:
		pt = get_scratch_regs(info);
		addr = &pt->ar_csd;
		break;

	      case UNW_AR_SSD:
		pt = get_scratch_regs(info);
		addr = &pt->ar_ssd;
		break;

	      default:
		UNW_DPRINT(0, "unwind.%s: trying to access non-existent ar%u\n",
			   __FUNCTION__, regnum);
		return -1;
	}

	if (write) {
		if (read_only(addr)) {
			UNW_DPRINT(0, "unwind.%s: ignoring attempt to write read-only location\n",
				__FUNCTION__);
		} else
			*addr = *val;
	} else
		*val = *addr;
	return 0;
}
EXPORT_SYMBOL(unw_access_ar);

int
unw_access_pr (struct unw_frame_info *info, unsigned long *val, int write)
{
	unsigned long *addr;

	addr = info->pr_loc;
	if (!addr)
		addr = &info->sw->pr;

	if (write) {
		if (read_only(addr)) {
			UNW_DPRINT(0, "unwind.%s: ignoring attempt to write read-only location\n",
				__FUNCTION__);
		} else
			*addr = *val;
	} else
		*val = *addr;
	return 0;
}
EXPORT_SYMBOL(unw_access_pr);


/* Routines to manipulate the state stack.  */

static inline void
push (struct unw_state_record *sr)
{
	struct unw_reg_state *rs;

	rs = alloc_reg_state();
	if (!rs) {
		printk(KERN_ERR "unwind: cannot stack reg state!\n");
		return;
	}
	memcpy(rs, &sr->curr, sizeof(*rs));
	sr->curr.next = rs;
}

static void
pop (struct unw_state_record *sr)
{
	struct unw_reg_state *rs = sr->curr.next;

	if (!rs) {
		printk(KERN_ERR "unwind: stack underflow!\n");
		return;
	}
	memcpy(&sr->curr, rs, sizeof(*rs));
	free_reg_state(rs);
}

/* Make a copy of the state stack.  Non-recursive to avoid stack overflows.  */
static struct unw_reg_state *
dup_state_stack (struct unw_reg_state *rs)
{
	struct unw_reg_state *copy, *prev = NULL, *first = NULL;

	while (rs) {
		copy = alloc_reg_state();
		if (!copy) {
			printk(KERN_ERR "unwind.dup_state_stack: out of memory\n");
			return NULL;
		}
		memcpy(copy, rs, sizeof(*copy));
		if (first)
			prev->next = copy;
		else
			first = copy;
		rs = rs->next;
		prev = copy;
	}
	return first;
}

/* Free all stacked register states (but not RS itself).  */
static void
free_state_stack (struct unw_reg_state *rs)
{
	struct unw_reg_state *p, *next;

	for (p = rs->next; p != NULL; p = next) {
		next = p->next;
		free_reg_state(p);
	}
	rs->next = NULL;
}

/* Unwind decoder routines */

static enum unw_register_index __attribute_const__
decode_abreg (unsigned char abreg, int memory)
{
	switch (abreg) {
	      case 0x04 ... 0x07: return UNW_REG_R4 + (abreg - 0x04);
	      case 0x22 ... 0x25: return UNW_REG_F2 + (abreg - 0x22);
	      case 0x30 ... 0x3f: return UNW_REG_F16 + (abreg - 0x30);
	      case 0x41 ... 0x45: return UNW_REG_B1 + (abreg - 0x41);
	      case 0x60: return UNW_REG_PR;
	      case 0x61: return UNW_REG_PSP;
	      case 0x62: return memory ? UNW_REG_PRI_UNAT_MEM : UNW_REG_PRI_UNAT_GR;
	      case 0x63: return UNW_REG_RP;
	      case 0x64: return UNW_REG_BSP;
	      case 0x65: return UNW_REG_BSPSTORE;
	      case 0x66: return UNW_REG_RNAT;
	      case 0x67: return UNW_REG_UNAT;
	      case 0x68: return UNW_REG_FPSR;
	      case 0x69: return UNW_REG_PFS;
	      case 0x6a: return UNW_REG_LC;
	      default:
		break;
	}
	UNW_DPRINT(0, "unwind.%s: bad abreg=0x%x\n", __FUNCTION__, abreg);
	return UNW_REG_LC;
}

static void
set_reg (struct unw_reg_info *reg, enum unw_where where, int when, unsigned long val)
{
	reg->val = val;
	reg->where = where;
	if (reg->when == UNW_WHEN_NEVER)
		reg->when = when;
}

static void
alloc_spill_area (unsigned long *offp, unsigned long regsize,
		  struct unw_reg_info *lo, struct unw_reg_info *hi)
{
	struct unw_reg_info *reg;

	for (reg = hi; reg >= lo; --reg) {
		if (reg->where == UNW_WHERE_SPILL_HOME) {
			reg->where = UNW_WHERE_PSPREL;
			*offp -= regsize;
			reg->val = *offp;
		}
	}
}

static inline void
spill_next_when (struct unw_reg_info **regp, struct unw_reg_info *lim, unw_word t)
{
	struct unw_reg_info *reg;

	for (reg = *regp; reg <= lim; ++reg) {
		if (reg->where == UNW_WHERE_SPILL_HOME) {
			reg->when = t;
			*regp = reg + 1;
			return;
		}
	}
	UNW_DPRINT(0, "unwind.%s: excess spill!\n",  __FUNCTION__);
}

static inline void
finish_prologue (struct unw_state_record *sr)
{
	struct unw_reg_info *reg;
	unsigned long off;
	int i;

	/*
	 * First, resolve implicit register save locations (see Section "11.4.2.3 Rules
	 * for Using Unwind Descriptors", rule 3):
	 */
	for (i = 0; i < (int) ARRAY_SIZE(unw.save_order); ++i) {
		reg = sr->curr.reg + unw.save_order[i];
		if (reg->where == UNW_WHERE_GR_SAVE) {
			reg->where = UNW_WHERE_GR;
			reg->val = sr->gr_save_loc++;
		}
	}

	/*
	 * Next, compute when the fp, general, and branch registers get
	 * saved.  This must come before alloc_spill_area() because
	 * we need to know which registers are spilled to their home
	 * locations.
	 */
	if (sr->imask) {
		unsigned char kind, mask = 0, *cp = sr->imask;
		int t;
		static const unsigned char limit[3] = {
			UNW_REG_F31, UNW_REG_R7, UNW_REG_B5
		};
		struct unw_reg_info *(regs[3]);

		regs[0] = sr->curr.reg + UNW_REG_F2;
		regs[1] = sr->curr.reg + UNW_REG_R4;
		regs[2] = sr->curr.reg + UNW_REG_B1;

		for (t = 0; t < sr->region_len; ++t) {
			if ((t & 3) == 0)
				mask = *cp++;
			kind = (mask >> 2*(3-(t & 3))) & 3;
			if (kind > 0)
				spill_next_when(&regs[kind - 1], sr->curr.reg + limit[kind - 1],
						sr->region_start + t);
		}
	}
	/*
	 * Next, lay out the memory stack spill area:
	 */
	if (sr->any_spills) {
		off = sr->spill_offset;
		alloc_spill_area(&off, 16, sr->curr.reg + UNW_REG_F2, sr->curr.reg + UNW_REG_F31);
		alloc_spill_area(&off,  8, sr->curr.reg + UNW_REG_B1, sr->curr.reg + UNW_REG_B5);
		alloc_spill_area(&off,  8, sr->curr.reg + UNW_REG_R4, sr->curr.reg + UNW_REG_R7);
	}
}

/*
 * Region header descriptors.
 */

static void
desc_prologue (int body, unw_word rlen, unsigned char mask, unsigned char grsave,
	       struct unw_state_record *sr)
{
	int i, region_start;

	if (!(sr->in_body || sr->first_region))
		finish_prologue(sr);
	sr->first_region = 0;

	/* check if we're done: */
	if (sr->when_target < sr->region_start + sr->region_len) {
		sr->done = 1;
		return;
	}

	region_start = sr->region_start + sr->region_len;

	for (i = 0; i < sr->epilogue_count; ++i)
		pop(sr);
	sr->epilogue_count = 0;
	sr->epilogue_start = UNW_WHEN_NEVER;

	sr->region_start = region_start;
	sr->region_len = rlen;
	sr->in_body = body;

	if (!body) {
		push(sr);

		for (i = 0; i < 4; ++i) {
			if (mask & 0x8)
				set_reg(sr->curr.reg + unw.save_order[i], UNW_WHERE_GR,
					sr->region_start + sr->region_len - 1, grsave++);
			mask <<= 1;
		}
		sr->gr_save_loc = grsave;
		sr->any_spills = 0;
		sr->imask = NULL;
		sr->spill_offset = 0x10;	/* default to psp+16 */
	}
}

/*
 * Prologue descriptors.
 */

static inline void
desc_abi (unsigned char abi, unsigned char context, struct unw_state_record *sr)
{
	if (abi == 3 && context == 'i') {
		sr->flags |= UNW_FLAG_INTERRUPT_FRAME;
		UNW_DPRINT(3, "unwind.%s: interrupt frame\n",  __FUNCTION__);
	}
	else
		UNW_DPRINT(0, "unwind%s: ignoring unwabi(abi=0x%x,context=0x%x)\n",
				__FUNCTION__, abi, context);
}

static inline void
desc_br_gr (unsigned char brmask, unsigned char gr, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 5; ++i) {
		if (brmask & 1)
			set_reg(sr->curr.reg + UNW_REG_B1 + i, UNW_WHERE_GR,
				sr->region_start + sr->region_len - 1, gr++);
		brmask >>= 1;
	}
}

static inline void
desc_br_mem (unsigned char brmask, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 5; ++i) {
		if (brmask & 1) {
			set_reg(sr->curr.reg + UNW_REG_B1 + i, UNW_WHERE_SPILL_HOME,
				sr->region_start + sr->region_len - 1, 0);
			sr->any_spills = 1;
		}
		brmask >>= 1;
	}
}

static inline void
desc_frgr_mem (unsigned char grmask, unw_word frmask, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 4; ++i) {
		if ((grmask & 1) != 0) {
			set_reg(sr->curr.reg + UNW_REG_R4 + i, UNW_WHERE_SPILL_HOME,
				sr->region_start + sr->region_len - 1, 0);
			sr->any_spills = 1;
		}
		grmask >>= 1;
	}
	for (i = 0; i < 20; ++i) {
		if ((frmask & 1) != 0) {
			int base = (i < 4) ? UNW_REG_F2 : UNW_REG_F16 - 4;
			set_reg(sr->curr.reg + base + i, UNW_WHERE_SPILL_HOME,
				sr->region_start + sr->region_len - 1, 0);
			sr->any_spills = 1;
		}
		frmask >>= 1;
	}
}

static inline void
desc_fr_mem (unsigned char frmask, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 4; ++i) {
		if ((frmask & 1) != 0) {
			set_reg(sr->curr.reg + UNW_REG_F2 + i, UNW_WHERE_SPILL_HOME,
				sr->region_start + sr->region_len - 1, 0);
			sr->any_spills = 1;
		}
		frmask >>= 1;
	}
}

static inline void
desc_gr_gr (unsigned char grmask, unsigned char gr, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 4; ++i) {
		if ((grmask & 1) != 0)
			set_reg(sr->curr.reg + UNW_REG_R4 + i, UNW_WHERE_GR,
				sr->region_start + sr->region_len - 1, gr++);
		grmask >>= 1;
	}
}

static inline void
desc_gr_mem (unsigned char grmask, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 4; ++i) {
		if ((grmask & 1) != 0) {
			set_reg(sr->curr.reg + UNW_REG_R4 + i, UNW_WHERE_SPILL_HOME,
				sr->region_start + sr->region_len - 1, 0);
			sr->any_spills = 1;
		}
		grmask >>= 1;
	}
}

static inline void
desc_mem_stack_f (unw_word t, unw_word size, struct unw_state_record *sr)
{
	set_reg(sr->curr.reg + UNW_REG_PSP, UNW_WHERE_NONE,
		sr->region_start + min_t(int, t, sr->region_len - 1), 16*size);
}

static inline void
desc_mem_stack_v (unw_word t, struct unw_state_record *sr)
{
	sr->curr.reg[UNW_REG_PSP].when = sr->region_start + min_t(int, t, sr->region_len - 1);
}

static inline void
desc_reg_gr (unsigned char reg, unsigned char dst, struct unw_state_record *sr)
{
	set_reg(sr->curr.reg + reg, UNW_WHERE_GR, sr->region_start + sr->region_len - 1, dst);
}

static inline void
desc_reg_psprel (unsigned char reg, unw_word pspoff, struct unw_state_record *sr)
{
	set_reg(sr->curr.reg + reg, UNW_WHERE_PSPREL, sr->region_start + sr->region_len - 1,
		0x10 - 4*pspoff);
}

static inline void
desc_reg_sprel (unsigned char reg, unw_word spoff, struct unw_state_record *sr)
{
	set_reg(sr->curr.reg + reg, UNW_WHERE_SPREL, sr->region_start + sr->region_len - 1,
		4*spoff);
}

static inline void
desc_rp_br (unsigned char dst, struct unw_state_record *sr)
{
	sr->return_link_reg = dst;
}

static inline void
desc_reg_when (unsigned char regnum, unw_word t, struct unw_state_record *sr)
{
	struct unw_reg_info *reg = sr->curr.reg + regnum;

	if (reg->where == UNW_WHERE_NONE)
		reg->where = UNW_WHERE_GR_SAVE;
	reg->when = sr->region_start + min_t(int, t, sr->region_len - 1);
}

static inline void
desc_spill_base (unw_word pspoff, struct unw_state_record *sr)
{
	sr->spill_offset = 0x10 - 4*pspoff;
}

static inline unsigned char *
desc_spill_mask (unsigned char *imaskp, struct unw_state_record *sr)
{
	sr->imask = imaskp;
	return imaskp + (2*sr->region_len + 7)/8;
}

/*
 * Body descriptors.
 */
static inline void
desc_epilogue (unw_word t, unw_word ecount, struct unw_state_record *sr)
{
	sr->epilogue_start = sr->region_start + sr->region_len - 1 - t;
	sr->epilogue_count = ecount + 1;
}

static inline void
desc_copy_state (unw_word label, struct unw_state_record *sr)
{
	struct unw_labeled_state *ls;

	for (ls = sr->labeled_states; ls; ls = ls->next) {
		if (ls->label == label) {
			free_state_stack(&sr->curr);
			memcpy(&sr->curr, &ls->saved_state, sizeof(sr->curr));
			sr->curr.next = dup_state_stack(ls->saved_state.next);
			return;
		}
	}
	printk(KERN_ERR "unwind: failed to find state labeled 0x%lx\n", label);
}

static inline void
desc_label_state (unw_word label, struct unw_state_record *sr)
{
	struct unw_labeled_state *ls;

	ls = alloc_labeled_state();
	if (!ls) {
		printk(KERN_ERR "unwind.desc_label_state(): out of memory\n");
		return;
	}
	ls->label = label;
	memcpy(&ls->saved_state, &sr->curr, sizeof(ls->saved_state));
	ls->saved_state.next = dup_state_stack(sr->curr.next);

	/* insert into list of labeled states: */
	ls->next = sr->labeled_states;
	sr->labeled_states = ls;
}

/*
 * General descriptors.
 */

static inline int
desc_is_active (unsigned char qp, unw_word t, struct unw_state_record *sr)
{
	if (sr->when_target <= sr->region_start + min_t(int, t, sr->region_len - 1))
		return 0;
	if (qp > 0) {
		if ((sr->pr_val & (1UL << qp)) == 0)
			return 0;
		sr->pr_mask |= (1UL << qp);
	}
	return 1;
}

static inline void
desc_restore_p (unsigned char qp, unw_word t, unsigned char abreg, struct unw_state_record *sr)
{
	struct unw_reg_info *r;

	if (!desc_is_active(qp, t, sr))
		return;

	r = sr->curr.reg + decode_abreg(abreg, 0);
	r->where = UNW_WHERE_NONE;
	r->when = UNW_WHEN_NEVER;
	r->val = 0;
}

static inline void
desc_spill_reg_p (unsigned char qp, unw_word t, unsigned char abreg, unsigned char x,
		     unsigned char ytreg, struct unw_state_record *sr)
{
	enum unw_where where = UNW_WHERE_GR;
	struct unw_reg_info *r;

	if (!desc_is_active(qp, t, sr))
		return;

	if (x)
		where = UNW_WHERE_BR;
	else if (ytreg & 0x80)
		where = UNW_WHERE_FR;

	r = sr->curr.reg + decode_abreg(abreg, 0);
	r->where = where;
	r->when = sr->region_start + min_t(int, t, sr->region_len - 1);
	r->val = (ytreg & 0x7f);
}

static inline void
desc_spill_psprel_p (unsigned char qp, unw_word t, unsigned char abreg, unw_word pspoff,
		     struct unw_state_record *sr)
{
	struct unw_reg_info *r;

	if (!desc_is_active(qp, t, sr))
		return;

	r = sr->curr.reg + decode_abreg(abreg, 1);
	r->where = UNW_WHERE_PSPREL;
	r->when = sr->region_start + min_t(int, t, sr->region_len - 1);
	r->val = 0x10 - 4*pspoff;
}

static inline void
desc_spill_sprel_p (unsigned char qp, unw_word t, unsigned char abreg, unw_word spoff,
		       struct unw_state_record *sr)
{
	struct unw_reg_info *r;

	if (!desc_is_active(qp, t, sr))
		return;

	r = sr->curr.reg + decode_abreg(abreg, 1);
	r->where = UNW_WHERE_SPREL;
	r->when = sr->region_start + min_t(int, t, sr->region_len - 1);
	r->val = 4*spoff;
}

#define UNW_DEC_BAD_CODE(code)			printk(KERN_ERR "unwind: unknown code 0x%02x\n", \
						       code);

/*
 * region headers:
 */
#define UNW_DEC_PROLOGUE_GR(fmt,r,m,gr,arg)	desc_prologue(0,r,m,gr,arg)
#define UNW_DEC_PROLOGUE(fmt,b,r,arg)		desc_prologue(b,r,0,32,arg)
/*
 * prologue descriptors:
 */
#define UNW_DEC_ABI(fmt,a,c,arg)		desc_abi(a,c,arg)
#define UNW_DEC_BR_GR(fmt,b,g,arg)		desc_br_gr(b,g,arg)
#define UNW_DEC_BR_MEM(fmt,b,arg)		desc_br_mem(b,arg)
#define UNW_DEC_FRGR_MEM(fmt,g,f,arg)		desc_frgr_mem(g,f,arg)
#define UNW_DEC_FR_MEM(fmt,f,arg)		desc_fr_mem(f,arg)
#define UNW_DEC_GR_GR(fmt,m,g,arg)		desc_gr_gr(m,g,arg)
#define UNW_DEC_GR_MEM(fmt,m,arg)		desc_gr_mem(m,arg)
#define UNW_DEC_MEM_STACK_F(fmt,t,s,arg)	desc_mem_stack_f(t,s,arg)
#define UNW_DEC_MEM_STACK_V(fmt,t,arg)		desc_mem_stack_v(t,arg)
#define UNW_DEC_REG_GR(fmt,r,d,arg)		desc_reg_gr(r,d,arg)
#define UNW_DEC_REG_PSPREL(fmt,r,o,arg)		desc_reg_psprel(r,o,arg)
#define UNW_DEC_REG_SPREL(fmt,r,o,arg)		desc_reg_sprel(r,o,arg)
#define UNW_DEC_REG_WHEN(fmt,r,t,arg)		desc_reg_when(r,t,arg)
#define UNW_DEC_PRIUNAT_WHEN_GR(fmt,t,arg)	desc_reg_when(UNW_REG_PRI_UNAT_GR,t,arg)
#define UNW_DEC_PRIUNAT_WHEN_MEM(fmt,t,arg)	desc_reg_when(UNW_REG_PRI_UNAT_MEM,t,arg)
#define UNW_DEC_PRIUNAT_GR(fmt,r,arg)		desc_reg_gr(UNW_REG_PRI_UNAT_GR,r,arg)
#define UNW_DEC_PRIUNAT_PSPREL(fmt,o,arg)	desc_reg_psprel(UNW_REG_PRI_UNAT_MEM,o,arg)
#define UNW_DEC_PRIUNAT_SPREL(fmt,o,arg)	desc_reg_sprel(UNW_REG_PRI_UNAT_MEM,o,arg)
#define UNW_DEC_RP_BR(fmt,d,arg)		desc_rp_br(d,arg)
#define UNW_DEC_SPILL_BASE(fmt,o,arg)		desc_spill_base(o,arg)
#define UNW_DEC_SPILL_MASK(fmt,m,arg)		(m = desc_spill_mask(m,arg))
/*
 * body descriptors:
 */
#define UNW_DEC_EPILOGUE(fmt,t,c,arg)		desc_epilogue(t,c,arg)
#define UNW_DEC_COPY_STATE(fmt,l,arg)		desc_copy_state(l,arg)
#define UNW_DEC_LABEL_STATE(fmt,l,arg)		desc_label_state(l,arg)
/*
 * general unwind descriptors:
 */
#define UNW_DEC_SPILL_REG_P(f,p,t,a,x,y,arg)	desc_spill_reg_p(p,t,a,x,y,arg)
#define UNW_DEC_SPILL_REG(f,t,a,x,y,arg)	desc_spill_reg_p(0,t,a,x,y,arg)
#define UNW_DEC_SPILL_PSPREL_P(f,p,t,a,o,arg)	desc_spill_psprel_p(p,t,a,o,arg)
#define UNW_DEC_SPILL_PSPREL(f,t,a,o,arg)	desc_spill_psprel_p(0,t,a,o,arg)
#define UNW_DEC_SPILL_SPREL_P(f,p,t,a,o,arg)	desc_spill_sprel_p(p,t,a,o,arg)
#define UNW_DEC_SPILL_SPREL(f,t,a,o,arg)	desc_spill_sprel_p(0,t,a,o,arg)
#define UNW_DEC_RESTORE_P(f,p,t,a,arg)		desc_restore_p(p,t,a,arg)
#define UNW_DEC_RESTORE(f,t,a,arg)		desc_restore_p(0,t,a,arg)

#include "unwind_decoder.c"


/* Unwind scripts. */

static inline unw_hash_index_t
hash (unsigned long ip)
{
#	define hashmagic	0x9e3779b97f4a7c16UL	/* based on (sqrt(5)/2-1)*2^64 */

	return (ip >> 4)*hashmagic >> (64 - UNW_LOG_HASH_SIZE);
#undef hashmagic
}

static inline long
cache_match (struct unw_script *script, unsigned long ip, unsigned long pr)
{
	read_lock(&script->lock);
	if (ip == script->ip && ((pr ^ script->pr_val) & script->pr_mask) == 0)
		/* keep the read lock... */
		return 1;
	read_unlock(&script->lock);
	return 0;
}

static inline struct unw_script *
script_lookup (struct unw_frame_info *info)
{
	struct unw_script *script = unw.cache + info->hint;
	unsigned short index;
	unsigned long ip, pr;

	if (UNW_DEBUG_ON(0))
		return NULL;	/* Always regenerate scripts in debug mode */

	STAT(++unw.stat.cache.lookups);

	ip = info->ip;
	pr = info->pr;

	if (cache_match(script, ip, pr)) {
		STAT(++unw.stat.cache.hinted_hits);
		return script;
	}

	index = unw.hash[hash(ip)];
	if (index >= UNW_CACHE_SIZE)
		return NULL;

	script = unw.cache + index;
	while (1) {
		if (cache_match(script, ip, pr)) {
			/* update hint; no locking required as single-word writes are atomic */
			STAT(++unw.stat.cache.normal_hits);
			unw.cache[info->prev_script].hint = script - unw.cache;
			return script;
		}
		if (script->coll_chain >= UNW_HASH_SIZE)
			return NULL;
		script = unw.cache + script->coll_chain;
		STAT(++unw.stat.cache.collision_chain_traversals);
	}
}

/*
 * On returning, a write lock for the SCRIPT is still being held.
 */
static inline struct unw_script *
script_new (unsigned long ip)
{
	struct unw_script *script, *prev, *tmp;
	unw_hash_index_t index;
	unsigned short head;

	STAT(++unw.stat.script.news);

	/*
	 * Can't (easily) use cmpxchg() here because of ABA problem
	 * that is intrinsic in cmpxchg()...
	 */
	head = unw.lru_head;
	script = unw.cache + head;
	unw.lru_head = script->lru_chain;

	/*
	 * We'd deadlock here if we interrupted a thread that is holding a read lock on
	 * script->lock.  Thus, if the write_trylock() fails, we simply bail out.  The
	 * alternative would be to disable interrupts whenever we hold a read-lock, but
	 * that seems silly.
	 */
	if (!write_trylock(&script->lock))
		return NULL;

	/* re-insert script at the tail of the LRU chain: */
	unw.cache[unw.lru_tail].lru_chain = head;
	unw.lru_tail = head;

	/* remove the old script from the hash table (if it's there): */
	if (script->ip) {
		index = hash(script->ip);
		tmp = unw.cache + unw.hash[index];
		prev = NULL;
		while (1) {
			if (tmp == script) {
				if (prev)
					prev->coll_chain = tmp->coll_chain;
				else
					unw.hash[index] = tmp->coll_chain;
				break;
			} else
				prev = tmp;
			if (tmp->coll_chain >= UNW_CACHE_SIZE)
			/* old script wasn't in the hash-table */
				break;
			tmp = unw.cache + tmp->coll_chain;
		}
	}

	/* enter new script in the hash table */
	index = hash(ip);
	script->coll_chain = unw.hash[index];
	unw.hash[index] = script - unw.cache;

	script->ip = ip;	/* set new IP while we're holding the locks */

	STAT(if (script->coll_chain < UNW_CACHE_SIZE) ++unw.stat.script.collisions);

	script->flags = 0;
	script->hint = 0;
	script->count = 0;
	return script;
}

static void
script_finalize (struct unw_script *script, struct unw_state_record *sr)
{
	script->pr_mask = sr->pr_mask;
	script->pr_val = sr->pr_val;
	/*
	 * We could down-grade our write-lock on script->lock here but
	 * the rwlock API doesn't offer atomic lock downgrading, so
	 * we'll just keep the write-lock and release it later when
	 * we're done using the script.
	 */
}

static inline void
script_emit (struct unw_script *script, struct unw_insn insn)
{
	if (script->count >= UNW_MAX_SCRIPT_LEN) {
		UNW_DPRINT(0, "unwind.%s: script exceeds maximum size of %u instructions!\n",
			__FUNCTION__, UNW_MAX_SCRIPT_LEN);
		return;
	}
	script->insn[script->count++] = insn;
}

static inline void
emit_nat_info (struct unw_state_record *sr, int i, struct unw_script *script)
{
	struct unw_reg_info *r = sr->curr.reg + i;
	enum unw_insn_opcode opc;
	struct unw_insn insn;
	unsigned long val = 0;

	switch (r->where) {
	      case UNW_WHERE_GR:
		if (r->val >= 32) {
			/* register got spilled to a stacked register */
			opc = UNW_INSN_SETNAT_TYPE;
			val = UNW_NAT_REGSTK;
		} else
			/* register got spilled to a scratch register */
			opc = UNW_INSN_SETNAT_MEMSTK;
		break;

	      case UNW_WHERE_FR:
		opc = UNW_INSN_SETNAT_TYPE;
		val = UNW_NAT_VAL;
		break;

	      case UNW_WHERE_BR:
		opc = UNW_INSN_SETNAT_TYPE;
		val = UNW_NAT_NONE;
		break;

	      case UNW_WHERE_PSPREL:
	      case UNW_WHERE_SPREL:
		opc = UNW_INSN_SETNAT_MEMSTK;
		break;

	      default:
		UNW_DPRINT(0, "unwind.%s: don't know how to emit nat info for where = %u\n",
			   __FUNCTION__, r->where);
		return;
	}
	insn.opc = opc;
	insn.dst = unw.preg_index[i];
	insn.val = val;
	script_emit(script, insn);
}

static void
compile_reg (struct unw_state_record *sr, int i, struct unw_script *script)
{
	struct unw_reg_info *r = sr->curr.reg + i;
	enum unw_insn_opcode opc;
	unsigned long val, rval;
	struct unw_insn insn;
	long need_nat_info;

	if (r->where == UNW_WHERE_NONE || r->when >= sr->when_target)
		return;

	opc = UNW_INSN_MOVE;
	val = rval = r->val;
	need_nat_info = (i >= UNW_REG_R4 && i <= UNW_REG_R7);

	switch (r->where) {
	      case UNW_WHERE_GR:
		if (rval >= 32) {
			opc = UNW_INSN_MOVE_STACKED;
			val = rval - 32;
		} else if (rval >= 4 && rval <= 7) {
			if (need_nat_info) {
				opc = UNW_INSN_MOVE2;
				need_nat_info = 0;
			}
			val = unw.preg_index[UNW_REG_R4 + (rval - 4)];
		} else if (rval == 0) {
			opc = UNW_INSN_MOVE_CONST;
			val = 0;
		} else {
			/* register got spilled to a scratch register */
			opc = UNW_INSN_MOVE_SCRATCH;
			val = pt_regs_off(rval);
		}
		break;

	      case UNW_WHERE_FR:
		if (rval <= 5)
			val = unw.preg_index[UNW_REG_F2  + (rval -  2)];
		else if (rval >= 16 && rval <= 31)
			val = unw.preg_index[UNW_REG_F16 + (rval - 16)];
		else {
			opc = UNW_INSN_MOVE_SCRATCH;
			if (rval <= 11)
				val = offsetof(struct pt_regs, f6) + 16*(rval - 6);
			else
				UNW_DPRINT(0, "unwind.%s: kernel may not touch f%lu\n",
					   __FUNCTION__, rval);
		}
		break;

	      case UNW_WHERE_BR:
		if (rval >= 1 && rval <= 5)
			val = unw.preg_index[UNW_REG_B1 + (rval - 1)];
		else {
			opc = UNW_INSN_MOVE_SCRATCH;
			if (rval == 0)
				val = offsetof(struct pt_regs, b0);
			else if (rval == 6)
				val = offsetof(struct pt_regs, b6);
			else
				val = offsetof(struct pt_regs, b7);
		}
		break;

	      case UNW_WHERE_SPREL:
		opc = UNW_INSN_ADD_SP;
		break;

	      case UNW_WHERE_PSPREL:
		opc = UNW_INSN_ADD_PSP;
		break;

	      default:
		UNW_DPRINT(0, "unwind%s: register %u has unexpected `where' value of %u\n",
			   __FUNCTION__, i, r->where);
		break;
	}
	insn.opc = opc;
	insn.dst = unw.preg_index[i];
	insn.val = val;
	script_emit(script, insn);
	if (need_nat_info)
		emit_nat_info(sr, i, script);

	if (i == UNW_REG_PSP) {
		/*
		 * info->psp must contain the _value_ of the previous
		 * sp, not it's save location.  We get this by
		 * dereferencing the value we just stored in
		 * info->psp:
		 */
		insn.opc = UNW_INSN_LOAD;
		insn.dst = insn.val = unw.preg_index[UNW_REG_PSP];
		script_emit(script, insn);
	}
}

static inline const struct unw_table_entry *
lookup (struct unw_table *table, unsigned long rel_ip)
{
	const struct unw_table_entry *e = NULL;
	unsigned long lo, hi, mid;

	/* do a binary search for right entry: */
	for (lo = 0, hi = table->length; lo < hi; ) {
		mid = (lo + hi) / 2;
		e = &table->array[mid];
		if (rel_ip < e->start_offset)
			hi = mid;
		else if (rel_ip >= e->end_offset)
			lo = mid + 1;
		else
			break;
	}
	if (rel_ip < e->start_offset || rel_ip >= e->end_offset)
		return NULL;
	return e;
}

/*
 * Build an unwind script that unwinds from state OLD_STATE to the
 * entrypoint of the function that called OLD_STATE.
 */
static inline struct unw_script *
build_script (struct unw_frame_info *info)
{
	const struct unw_table_entry *e = NULL;
	struct unw_script *script = NULL;
	struct unw_labeled_state *ls, *next;
	unsigned long ip = info->ip;
	struct unw_state_record sr;
	struct unw_table *table;
	struct unw_reg_info *r;
	struct unw_insn insn;
	u8 *dp, *desc_end;
	u64 hdr;
	int i;
	STAT(unsigned long start, parse_start;)

	STAT(++unw.stat.script.builds; start = ia64_get_itc());

	/* build state record */
	memset(&sr, 0, sizeof(sr));
	for (r = sr.curr.reg; r < sr.curr.reg + UNW_NUM_REGS; ++r)
		r->when = UNW_WHEN_NEVER;
	sr.pr_val = info->pr;

	UNW_DPRINT(3, "unwind.%s: ip 0x%lx\n", __FUNCTION__, ip);
	script = script_new(ip);
	if (!script) {
		UNW_DPRINT(0, "unwind.%s: failed to create unwind script\n",  __FUNCTION__);
		STAT(unw.stat.script.build_time += ia64_get_itc() - start);
		return NULL;
	}
	unw.cache[info->prev_script].hint = script - unw.cache;

	/* search the kernels and the modules' unwind tables for IP: */

	STAT(parse_start = ia64_get_itc());

	for (table = unw.tables; table; table = table->next) {
		if (ip >= table->start && ip < table->end) {
			e = lookup(table, ip - table->segment_base);
			break;
		}
	}
	if (!e) {
		/* no info, return default unwinder (leaf proc, no mem stack, no saved regs)  */
		UNW_DPRINT(1, "unwind.%s: no unwind info for ip=0x%lx (prev ip=0x%lx)\n",
			__FUNCTION__, ip, unw.cache[info->prev_script].ip);
		sr.curr.reg[UNW_REG_RP].where = UNW_WHERE_BR;
		sr.curr.reg[UNW_REG_RP].when = -1;
		sr.curr.reg[UNW_REG_RP].val = 0;
		compile_reg(&sr, UNW_REG_RP, script);
		script_finalize(script, &sr);
		STAT(unw.stat.script.parse_time += ia64_get_itc() - parse_start);
		STAT(unw.stat.script.build_time += ia64_get_itc() - start);
		return script;
	}

	sr.when_target = (3*((ip & ~0xfUL) - (table->segment_base + e->start_offset))/16
			  + (ip & 0xfUL));
	hdr = *(u64 *) (table->segment_base + e->info_offset);
	dp =   (u8 *)  (table->segment_base + e->info_offset + 8);
	desc_end = dp + 8*UNW_LENGTH(hdr);

	while (!sr.done && dp < desc_end)
		dp = unw_decode(dp, sr.in_body, &sr);

	if (sr.when_target > sr.epilogue_start) {
		/*
		 * sp has been restored and all values on the memory stack below
		 * psp also have been restored.
		 */
		sr.curr.reg[UNW_REG_PSP].val = 0;
		sr.curr.reg[UNW_REG_PSP].where = UNW_WHERE_NONE;
		sr.curr.reg[UNW_REG_PSP].when = UNW_WHEN_NEVER;
		for (r = sr.curr.reg; r < sr.curr.reg + UNW_NUM_REGS; ++r)
			if ((r->where == UNW_WHERE_PSPREL && r->val <= 0x10)
			    || r->where == UNW_WHERE_SPREL)
			{
				r->val = 0;
				r->where = UNW_WHERE_NONE;
				r->when = UNW_WHEN_NEVER;
			}
	}

	script->flags = sr.flags;

	/*
	 * If RP did't get saved, generate entry for the return link
	 * register.
	 */
	if (sr.curr.reg[UNW_REG_RP].when >= sr.when_target) {
		sr.curr.reg[UNW_REG_RP].where = UNW_WHERE_BR;
		sr.curr.reg[UNW_REG_RP].when = -1;
		sr.curr.reg[UNW_REG_RP].val = sr.return_link_reg;
		UNW_DPRINT(1, "unwind.%s: using default for rp at ip=0x%lx where=%d val=0x%lx\n",
			   __FUNCTION__, ip, sr.curr.reg[UNW_REG_RP].where,
			   sr.curr.reg[UNW_REG_RP].val);
	}

#ifdef UNW_DEBUG
	UNW_DPRINT(1, "unwind.%s: state record for func 0x%lx, t=%u:\n",
		__FUNCTION__, table->segment_base + e->start_offset, sr.when_target);
	for (r = sr.curr.reg; r < sr.curr.reg + UNW_NUM_REGS; ++r) {
		if (r->where != UNW_WHERE_NONE || r->when != UNW_WHEN_NEVER) {
			UNW_DPRINT(1, "  %s <- ", unw.preg_name[r - sr.curr.reg]);
			switch (r->where) {
			      case UNW_WHERE_GR:     UNW_DPRINT(1, "r%lu", r->val); break;
			      case UNW_WHERE_FR:     UNW_DPRINT(1, "f%lu", r->val); break;
			      case UNW_WHERE_BR:     UNW_DPRINT(1, "b%lu", r->val); break;
			      case UNW_WHERE_SPREL:  UNW_DPRINT(1, "[sp+0x%lx]", r->val); break;
			      case UNW_WHERE_PSPREL: UNW_DPRINT(1, "[psp+0x%lx]", r->val); break;
			      case UNW_WHERE_NONE:
				UNW_DPRINT(1, "%s+0x%lx", unw.preg_name[r - sr.curr.reg], r->val);
				break;

			      default:
				UNW_DPRINT(1, "BADWHERE(%d)", r->where);
				break;
			}
			UNW_DPRINT(1, "\t\t%d\n", r->when);
		}
	}
#endif

	STAT(unw.stat.script.parse_time += ia64_get_itc() - parse_start);

	/* translate state record into unwinder instructions: */

	/*
	 * First, set psp if we're dealing with a fixed-size frame;
	 * subsequent instructions may depend on this value.
	 */
	if (sr.when_target > sr.curr.reg[UNW_REG_PSP].when
	    && (sr.curr.reg[UNW_REG_PSP].where == UNW_WHERE_NONE)
	    && sr.curr.reg[UNW_REG_PSP].val != 0) {
		/* new psp is sp plus frame size */
		insn.opc = UNW_INSN_ADD;
		insn.dst = offsetof(struct unw_frame_info, psp)/8;
		insn.val = sr.curr.reg[UNW_REG_PSP].val;	/* frame size */
		script_emit(script, insn);
	}

	/* determine where the primary UNaT is: */
	if (sr.when_target < sr.curr.reg[UNW_REG_PRI_UNAT_GR].when)
		i = UNW_REG_PRI_UNAT_MEM;
	else if (sr.when_target < sr.curr.reg[UNW_REG_PRI_UNAT_MEM].when)
		i = UNW_REG_PRI_UNAT_GR;
	else if (sr.curr.reg[UNW_REG_PRI_UNAT_MEM].when > sr.curr.reg[UNW_REG_PRI_UNAT_GR].when)
		i = UNW_REG_PRI_UNAT_MEM;
	else
		i = UNW_REG_PRI_UNAT_GR;

	compile_reg(&sr, i, script);

	for (i = UNW_REG_BSP; i < UNW_NUM_REGS; ++i)
		compile_reg(&sr, i, script);

	/* free labeled register states & stack: */

	STAT(parse_start = ia64_get_itc());
	for (ls = sr.labeled_states; ls; ls = next) {
		next = ls->next;
		free_state_stack(&ls->saved_state);
		free_labeled_state(ls);
	}
	free_state_stack(&sr.curr);
	STAT(unw.stat.script.parse_time += ia64_get_itc() - parse_start);

	script_finalize(script, &sr);
	STAT(unw.stat.script.build_time += ia64_get_itc() - start);
	return script;
}

/*
 * Apply the unwinding actions represented by OPS and update SR to
 * reflect the state that existed upon entry to the function that this
 * unwinder represents.
 */
static inline void
run_script (struct unw_script *script, struct unw_frame_info *state)
{
	struct unw_insn *ip, *limit, next_insn;
	unsigned long opc, dst, val, off;
	unsigned long *s = (unsigned long *) state;
	STAT(unsigned long start;)

	STAT(++unw.stat.script.runs; start = ia64_get_itc());
	state->flags = script->flags;
	ip = script->insn;
	limit = script->insn + script->count;
	next_insn = *ip;

	while (ip++ < limit) {
		opc = next_insn.opc;
		dst = next_insn.dst;
		val = next_insn.val;
		next_insn = *ip;

	  redo:
		switch (opc) {
		      case UNW_INSN_ADD:
			s[dst] += val;
			break;

		      case UNW_INSN_MOVE2:
			if (!s[val])
				goto lazy_init;
			s[dst+1] = s[val+1];
			s[dst] = s[val];
			break;

		      case UNW_INSN_MOVE:
			if (!s[val])
				goto lazy_init;
			s[dst] = s[val];
			break;

		      case UNW_INSN_MOVE_SCRATCH:
			if (state->pt) {
				s[dst] = (unsigned long) get_scratch_regs(state) + val;
			} else {
				s[dst] = 0;
				UNW_DPRINT(0, "unwind.%s: no state->pt, dst=%ld, val=%ld\n",
					   __FUNCTION__, dst, val);
			}
			break;

		      case UNW_INSN_MOVE_CONST:
			if (val == 0)
				s[dst] = (unsigned long) &unw.r0;
			else {
				s[dst] = 0;
				UNW_DPRINT(0, "unwind.%s: UNW_INSN_MOVE_CONST bad val=%ld\n",
					   __FUNCTION__, val);
			}
			break;


		      case UNW_INSN_MOVE_STACKED:
			s[dst] = (unsigned long) ia64_rse_skip_regs((unsigned long *)state->bsp,
								    val);
			break;

		      case UNW_INSN_ADD_PSP:
			s[dst] = state->psp + val;
			break;

		      case UNW_INSN_ADD_SP:
			s[dst] = state->sp + val;
			break;

		      case UNW_INSN_SETNAT_MEMSTK:
			if (!state->pri_unat_loc)
				state->pri_unat_loc = &state->sw->caller_unat;
			/* register off. is a multiple of 8, so the least 3 bits (type) are 0 */
			s[dst+1] = ((unsigned long) state->pri_unat_loc - s[dst]) | UNW_NAT_MEMSTK;
			break;

		      case UNW_INSN_SETNAT_TYPE:
			s[dst+1] = val;
			break;

		      case UNW_INSN_LOAD:
#ifdef UNW_DEBUG
			if ((s[val] & (local_cpu_data->unimpl_va_mask | 0x7)) != 0
			    || s[val] < TASK_SIZE)
			{
				UNW_DPRINT(0, "unwind.%s: rejecting bad psp=0x%lx\n",
					   __FUNCTION__, s[val]);
				break;
			}
#endif
			s[dst] = *(unsigned long *) s[val];
			break;
		}
	}
	STAT(unw.stat.script.run_time += ia64_get_itc() - start);
	return;

  lazy_init:
	off = unw.sw_off[val];
	s[val] = (unsigned long) state->sw + off;
	if (off >= offsetof(struct switch_stack, r4) && off <= offsetof(struct switch_stack, r7))
		/*
		 * We're initializing a general register: init NaT info, too.  Note that
		 * the offset is a multiple of 8 which gives us the 3 bits needed for
		 * the type field.
		 */
		s[val+1] = (offsetof(struct switch_stack, ar_unat) - off) | UNW_NAT_MEMSTK;
	goto redo;
}

static int
find_save_locs (struct unw_frame_info *info)
{
	int have_write_lock = 0;
	struct unw_script *scr;
	unsigned long flags = 0;

	if ((info->ip & (local_cpu_data->unimpl_va_mask | 0xf)) || info->ip < TASK_SIZE) {
		/* don't let obviously bad addresses pollute the cache */
		/* FIXME: should really be level 0 but it occurs too often. KAO */
		UNW_DPRINT(1, "unwind.%s: rejecting bad ip=0x%lx\n", __FUNCTION__, info->ip);
		info->rp_loc = NULL;
		return -1;
	}

	scr = script_lookup(info);
	if (!scr) {
		spin_lock_irqsave(&unw.lock, flags);
		scr = build_script(info);
		if (!scr) {
			spin_unlock_irqrestore(&unw.lock, flags);
			UNW_DPRINT(0,
				   "unwind.%s: failed to locate/build unwind script for ip %lx\n",
				   __FUNCTION__, info->ip);
			return -1;
		}
		have_write_lock = 1;
	}
	info->hint = scr->hint;
	info->prev_script = scr - unw.cache;

	run_script(scr, info);

	if (have_write_lock) {
		write_unlock(&scr->lock);
		spin_unlock_irqrestore(&unw.lock, flags);
	} else
		read_unlock(&scr->lock);
	return 0;
}

int
unw_unwind (struct unw_frame_info *info)
{
	unsigned long prev_ip, prev_sp, prev_bsp;
	unsigned long ip, pr, num_regs;
	STAT(unsigned long start, flags;)
	int retval;

	STAT(local_irq_save(flags); ++unw.stat.api.unwinds; start = ia64_get_itc());

	prev_ip = info->ip;
	prev_sp = info->sp;
	prev_bsp = info->bsp;

	/* restore the ip */
	if (!info->rp_loc) {
		/* FIXME: should really be level 0 but it occurs too often. KAO */
		UNW_DPRINT(1, "unwind.%s: failed to locate return link (ip=0x%lx)!\n",
			   __FUNCTION__, info->ip);
		STAT(unw.stat.api.unwind_time += ia64_get_itc() - start; local_irq_restore(flags));
		return -1;
	}
	ip = info->ip = *info->rp_loc;
	if (ip < GATE_ADDR) {
		UNW_DPRINT(2, "unwind.%s: reached user-space (ip=0x%lx)\n", __FUNCTION__, ip);
		STAT(unw.stat.api.unwind_time += ia64_get_itc() - start; local_irq_restore(flags));
		return -1;
	}

	/* restore the cfm: */
	if (!info->pfs_loc) {
		UNW_DPRINT(0, "unwind.%s: failed to locate ar.pfs!\n", __FUNCTION__);
		STAT(unw.stat.api.unwind_time += ia64_get_itc() - start; local_irq_restore(flags));
		return -1;
	}
	info->cfm_loc = info->pfs_loc;

	/* restore the bsp: */
	pr = info->pr;
	num_regs = 0;
	if ((info->flags & UNW_FLAG_INTERRUPT_FRAME)) {
		info->pt = info->sp + 16;
		if ((pr & (1UL << PRED_NON_SYSCALL)) != 0)
			num_regs = *info->cfm_loc & 0x7f;		/* size of frame */
		info->pfs_loc =
			(unsigned long *) (info->pt + offsetof(struct pt_regs, ar_pfs));
		UNW_DPRINT(3, "unwind.%s: interrupt_frame pt 0x%lx\n", __FUNCTION__, info->pt);
	} else
		num_regs = (*info->cfm_loc >> 7) & 0x7f;	/* size of locals */
	info->bsp = (unsigned long) ia64_rse_skip_regs((unsigned long *) info->bsp, -num_regs);
	if (info->bsp < info->regstk.limit || info->bsp > info->regstk.top) {
		UNW_DPRINT(0, "unwind.%s: bsp (0x%lx) out of range [0x%lx-0x%lx]\n",
			__FUNCTION__, info->bsp, info->regstk.limit, info->regstk.top);
		STAT(unw.stat.api.unwind_time += ia64_get_itc() - start; local_irq_restore(flags));
		return -1;
	}

	/* restore the sp: */
	info->sp = info->psp;
	if (info->sp < info->memstk.top || info->sp > info->memstk.limit) {
		UNW_DPRINT(0, "unwind.%s: sp (0x%lx) out of range [0x%lx-0x%lx]\n",
			__FUNCTION__, info->sp, info->memstk.top, info->memstk.limit);
		STAT(unw.stat.api.unwind_time += ia64_get_itc() - start; local_irq_restore(flags));
		return -1;
	}

	if (info->ip == prev_ip && info->sp == prev_sp && info->bsp == prev_bsp) {
		UNW_DPRINT(0, "unwind.%s: ip, sp, bsp unchanged; stopping here (ip=0x%lx)\n",
			   __FUNCTION__, ip);
		STAT(unw.stat.api.unwind_time += ia64_get_itc() - start; local_irq_restore(flags));
		return -1;
	}

	/* as we unwind, the saved ar.unat becomes the primary unat: */
	info->pri_unat_loc = info->unat_loc;

	/* finally, restore the predicates: */
	unw_get_pr(info, &info->pr);

	retval = find_save_locs(info);
	STAT(unw.stat.api.unwind_time += ia64_get_itc() - start; local_irq_restore(flags));
	return retval;
}
EXPORT_SYMBOL(unw_unwind);

int
unw_unwind_to_user (struct unw_frame_info *info)
{
	unsigned long ip, sp, pr = info->pr;

	do {
		unw_get_sp(info, &sp);
		if ((long)((unsigned long)info->task + IA64_STK_OFFSET - sp)
		    < IA64_PT_REGS_SIZE) {
			UNW_DPRINT(0, "unwind.%s: ran off the top of the kernel stack\n",
				   __FUNCTION__);
			break;
		}
		if (unw_is_intr_frame(info) &&
		    (pr & (1UL << PRED_USER_STACK)))
			return 0;
		if (unw_get_pr (info, &pr) < 0) {
			unw_get_rp(info, &ip);
			UNW_DPRINT(0, "unwind.%s: failed to read "
				   "predicate register (ip=0x%lx)\n",
				__FUNCTION__, ip);
			return -1;
		}
	} while (unw_unwind(info) >= 0);
	unw_get_ip(info, &ip);
	UNW_DPRINT(0, "unwind.%s: failed to unwind to user-level (ip=0x%lx)\n",
		   __FUNCTION__, ip);
	return -1;
}
EXPORT_SYMBOL(unw_unwind_to_user);

static void
init_frame_info (struct unw_frame_info *info, struct task_struct *t,
		 struct switch_stack *sw, unsigned long stktop)
{
	unsigned long rbslimit, rbstop, stklimit;
	STAT(unsigned long start, flags;)

	STAT(local_irq_save(flags); ++unw.stat.api.inits; start = ia64_get_itc());

	/*
	 * Subtle stuff here: we _could_ unwind through the switch_stack frame but we
	 * don't want to do that because it would be slow as each preserved register would
	 * have to be processed.  Instead, what we do here is zero out the frame info and
	 * start the unwind process at the function that created the switch_stack frame.
	 * When a preserved value in switch_stack needs to be accessed, run_script() will
	 * initialize the appropriate pointer on demand.
	 */
	memset(info, 0, sizeof(*info));

	rbslimit = (unsigned long) t + IA64_RBS_OFFSET;
	rbstop   = sw->ar_bspstore;
	if (rbstop - (unsigned long) t >= IA64_STK_OFFSET)
		rbstop = rbslimit;

	stklimit = (unsigned long) t + IA64_STK_OFFSET;
	if (stktop <= rbstop)
		stktop = rbstop;

	info->regstk.limit = rbslimit;
	info->regstk.top   = rbstop;
	info->memstk.limit = stklimit;
	info->memstk.top   = stktop;
	info->task = t;
	info->sw  = sw;
	info->sp = info->psp = stktop;
	info->pr = sw->pr;
	UNW_DPRINT(3, "unwind.%s:\n"
		   "  task   0x%lx\n"
		   "  rbs = [0x%lx-0x%lx)\n"
		   "  stk = [0x%lx-0x%lx)\n"
		   "  pr     0x%lx\n"
		   "  sw     0x%lx\n"
		   "  sp     0x%lx\n",
		   __FUNCTION__, (unsigned long) t, rbslimit, rbstop, stktop, stklimit,
		   info->pr, (unsigned long) info->sw, info->sp);
	STAT(unw.stat.api.init_time += ia64_get_itc() - start; local_irq_restore(flags));
}

void
unw_init_frame_info (struct unw_frame_info *info, struct task_struct *t, struct switch_stack *sw)
{
	unsigned long sol;

	init_frame_info(info, t, sw, (unsigned long) (sw + 1) - 16);
	info->cfm_loc = &sw->ar_pfs;
	sol = (*info->cfm_loc >> 7) & 0x7f;
	info->bsp = (unsigned long) ia64_rse_skip_regs((unsigned long *) info->regstk.top, -sol);
	info->ip = sw->b0;
	UNW_DPRINT(3, "unwind.%s:\n"
		   "  bsp    0x%lx\n"
		   "  sol    0x%lx\n"
		   "  ip     0x%lx\n",
		   __FUNCTION__, info->bsp, sol, info->ip);
	find_save_locs(info);
}

EXPORT_SYMBOL(unw_init_frame_info);

void
unw_init_from_blocked_task (struct unw_frame_info *info, struct task_struct *t)
{
	struct switch_stack *sw = (struct switch_stack *) (t->thread.ksp + 16);

	UNW_DPRINT(1, "unwind.%s\n", __FUNCTION__);
	unw_init_frame_info(info, t, sw);
}
EXPORT_SYMBOL(unw_init_from_blocked_task);

static void
init_unwind_table (struct unw_table *table, const char *name, unsigned long segment_base,
		   unsigned long gp, const void *table_start, const void *table_end)
{
	const struct unw_table_entry *start = table_start, *end = table_end;

	table->name = name;
	table->segment_base = segment_base;
	table->gp = gp;
	table->start = segment_base + start[0].start_offset;
	table->end = segment_base + end[-1].end_offset;
	table->array = start;
	table->length = end - start;
}

void *
unw_add_unwind_table (const char *name, unsigned long segment_base, unsigned long gp,
		      const void *table_start, const void *table_end)
{
	const struct unw_table_entry *start = table_start, *end = table_end;
	struct unw_table *table;
	unsigned long flags;

	if (end - start <= 0) {
		UNW_DPRINT(0, "unwind.%s: ignoring attempt to insert empty unwind table\n",
			   __FUNCTION__);
		return NULL;
	}

	table = kmalloc(sizeof(*table), GFP_USER);
	if (!table)
		return NULL;

	init_unwind_table(table, name, segment_base, gp, table_start, table_end);

	spin_lock_irqsave(&unw.lock, flags);
	{
		/* keep kernel unwind table at the front (it's searched most commonly): */
		table->next = unw.tables->next;
		unw.tables->next = table;
	}
	spin_unlock_irqrestore(&unw.lock, flags);

	return table;
}

void
unw_remove_unwind_table (void *handle)
{
	struct unw_table *table, *prev;
	struct unw_script *tmp;
	unsigned long flags;
	long index;

	if (!handle) {
		UNW_DPRINT(0, "unwind.%s: ignoring attempt to remove non-existent unwind table\n",
			   __FUNCTION__);
		return;
	}

	table = handle;
	if (table == &unw.kernel_table) {
		UNW_DPRINT(0, "unwind.%s: sorry, freeing the kernel's unwind table is a "
			   "no-can-do!\n", __FUNCTION__);
		return;
	}

	spin_lock_irqsave(&unw.lock, flags);
	{
		/* first, delete the table: */

		for (prev = (struct unw_table *) &unw.tables; prev; prev = prev->next)
			if (prev->next == table)
				break;
		if (!prev) {
			UNW_DPRINT(0, "unwind.%s: failed to find unwind table %p\n",
				   __FUNCTION__, (void *) table);
			spin_unlock_irqrestore(&unw.lock, flags);
			return;
		}
		prev->next = table->next;
	}
	spin_unlock_irqrestore(&unw.lock, flags);

	/* next, remove hash table entries for this table */

	for (index = 0; index <= UNW_HASH_SIZE; ++index) {
		tmp = unw.cache + unw.hash[index];
		if (unw.hash[index] >= UNW_CACHE_SIZE
		    || tmp->ip < table->start || tmp->ip >= table->end)
			continue;

		write_lock(&tmp->lock);
		{
			if (tmp->ip >= table->start && tmp->ip < table->end) {
				unw.hash[index] = tmp->coll_chain;
				tmp->ip = 0;
			}
		}
		write_unlock(&tmp->lock);
	}

	kfree(table);
}

static int __init
create_gate_table (void)
{
	const struct unw_table_entry *entry, *start, *end;
	unsigned long *lp, segbase = GATE_ADDR;
	size_t info_size, size;
	char *info;
	Elf64_Phdr *punw = NULL, *phdr = (Elf64_Phdr *) (GATE_ADDR + GATE_EHDR->e_phoff);
	int i;

	for (i = 0; i < GATE_EHDR->e_phnum; ++i, ++phdr)
		if (phdr->p_type == PT_IA_64_UNWIND) {
			punw = phdr;
			break;
		}

	if (!punw) {
		printk("%s: failed to find gate DSO's unwind table!\n", __FUNCTION__);
		return 0;
	}

	start = (const struct unw_table_entry *) punw->p_vaddr;
	end = (struct unw_table_entry *) ((char *) start + punw->p_memsz);
	size  = 0;

	unw_add_unwind_table("linux-gate.so", segbase, 0, start, end);

	for (entry = start; entry < end; ++entry)
		size += 3*8 + 8 + 8*UNW_LENGTH(*(u64 *) (segbase + entry->info_offset));
	size += 8;	/* reserve space for "end of table" marker */

	unw.gate_table = kmalloc(size, GFP_KERNEL);
	if (!unw.gate_table) {
		unw.gate_table_size = 0;
		printk(KERN_ERR "%s: unable to create unwind data for gate page!\n", __FUNCTION__);
		return 0;
	}
	unw.gate_table_size = size;

	lp = unw.gate_table;
	info = (char *) unw.gate_table + size;

	for (entry = start; entry < end; ++entry, lp += 3) {
		info_size = 8 + 8*UNW_LENGTH(*(u64 *) (segbase + entry->info_offset));
		info -= info_size;
		memcpy(info, (char *) segbase + entry->info_offset, info_size);

		lp[0] = segbase + entry->start_offset;		/* start */
		lp[1] = segbase + entry->end_offset;		/* end */
		lp[2] = info - (char *) unw.gate_table;		/* info */
	}
	*lp = 0;	/* end-of-table marker */
	return 0;
}

__initcall(create_gate_table);

void __init
unw_init (void)
{
	extern char __gp[];
	extern void unw_hash_index_t_is_too_narrow (void);
	long i, off;

	if (8*sizeof(unw_hash_index_t) < UNW_LOG_HASH_SIZE)
		unw_hash_index_t_is_too_narrow();

	unw.sw_off[unw.preg_index[UNW_REG_PRI_UNAT_GR]] = SW(CALLER_UNAT);
	unw.sw_off[unw.preg_index[UNW_REG_BSPSTORE]] = SW(AR_BSPSTORE);
	unw.sw_off[unw.preg_index[UNW_REG_PFS]] = SW(AR_PFS);
	unw.sw_off[unw.preg_index[UNW_REG_RP]] = SW(B0);
	unw.sw_off[unw.preg_index[UNW_REG_UNAT]] = SW(CALLER_UNAT);
	unw.sw_off[unw.preg_index[UNW_REG_PR]] = SW(PR);
	unw.sw_off[unw.preg_index[UNW_REG_LC]] = SW(AR_LC);
	unw.sw_off[unw.preg_index[UNW_REG_FPSR]] = SW(AR_FPSR);
	for (i = UNW_REG_R4, off = SW(R4); i <= UNW_REG_R7; ++i, off += 8)
		unw.sw_off[unw.preg_index[i]] = off;
	for (i = UNW_REG_B1, off = SW(B1); i <= UNW_REG_B5; ++i, off += 8)
		unw.sw_off[unw.preg_index[i]] = off;
	for (i = UNW_REG_F2, off = SW(F2); i <= UNW_REG_F5; ++i, off += 16)
		unw.sw_off[unw.preg_index[i]] = off;
	for (i = UNW_REG_F16, off = SW(F16); i <= UNW_REG_F31; ++i, off += 16)
		unw.sw_off[unw.preg_index[i]] = off;

	for (i = 0; i < UNW_CACHE_SIZE; ++i) {
		if (i > 0)
			unw.cache[i].lru_chain = (i - 1);
		unw.cache[i].coll_chain = -1;
		rwlock_init(&unw.cache[i].lock);
	}
	unw.lru_head = UNW_CACHE_SIZE - 1;
	unw.lru_tail = 0;

	init_unwind_table(&unw.kernel_table, "kernel", KERNEL_START, (unsigned long) __gp,
			  __start_unwind, __end_unwind);
}

/*
 * DEPRECATED DEPRECATED DEPRECATED DEPRECATED DEPRECATED DEPRECATED DEPRECATED
 *
 *	This system call has been deprecated.  The new and improved way to get
 *	at the kernel's unwind info is via the gate DSO.  The address of the
 *	ELF header for this DSO is passed to user-level via AT_SYSINFO_EHDR.
 *
 * DEPRECATED DEPRECATED DEPRECATED DEPRECATED DEPRECATED DEPRECATED DEPRECATED
 *
 * This system call copies the unwind data into the buffer pointed to by BUF and returns
 * the size of the unwind data.  If BUF_SIZE is smaller than the size of the unwind data
 * or if BUF is NULL, nothing is copied, but the system call still returns the size of the
 * unwind data.
 *
 * The first portion of the unwind data contains an unwind table and rest contains the
 * associated unwind info (in no particular order).  The unwind table consists of a table
 * of entries of the form:
 *
 *	u64 start;	(64-bit address of start of function)
 *	u64 end;	(64-bit address of start of function)
 *	u64 info;	(BUF-relative offset to unwind info)
 *
 * The end of the unwind table is indicated by an entry with a START address of zero.
 *
 * Please see the IA-64 Software Conventions and Runtime Architecture manual for details
 * on the format of the unwind info.
 *
 * ERRORS
 *	EFAULT	BUF points outside your accessible address space.
 */
asmlinkage long
sys_getunwind (void __user *buf, size_t buf_size)
{
	if (buf && buf_size >= unw.gate_table_size)
		if (copy_to_user(buf, unw.gate_table, unw.gate_table_size) != 0)
			return -EFAULT;
	return unw.gate_table_size;
}