summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/include/asm/cmpxchg.h
blob: 05f246c0e36eb3855fd713b69f5681dee0637416 (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
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_POWERPC_CMPXCHG_H_
#define _ASM_POWERPC_CMPXCHG_H_

#ifdef __KERNEL__
#include <linux/compiler.h>
#include <asm/synch.h>
#include <linux/bug.h>

#ifdef __BIG_ENDIAN
#define BITOFF_CAL(size, off)	((sizeof(u32) - size - off) * BITS_PER_BYTE)
#else
#define BITOFF_CAL(size, off)	(off * BITS_PER_BYTE)
#endif

#define XCHG_GEN(type, sfx, cl)				\
static inline u32 __xchg_##type##sfx(volatile void *p, u32 val)	\
{								\
	unsigned int prev, prev_mask, tmp, bitoff, off;		\
								\
	off = (unsigned long)p % sizeof(u32);			\
	bitoff = BITOFF_CAL(sizeof(type), off);			\
	p -= off;						\
	val <<= bitoff;						\
	prev_mask = (u32)(type)-1 << bitoff;			\
								\
	__asm__ __volatile__(					\
"1:	lwarx   %0,0,%3\n"					\
"	andc	%1,%0,%5\n"					\
"	or	%1,%1,%4\n"					\
"	stwcx.	%1,0,%3\n"					\
"	bne-	1b\n"						\
	: "=&r" (prev), "=&r" (tmp), "+m" (*(u32*)p)		\
	: "r" (p), "r" (val), "r" (prev_mask)			\
	: "cc", cl);						\
								\
	return prev >> bitoff;					\
}

#define CMPXCHG_GEN(type, sfx, br, br2, cl)			\
static inline							\
u32 __cmpxchg_##type##sfx(volatile void *p, u32 old, u32 new)	\
{								\
	unsigned int prev, prev_mask, tmp, bitoff, off;		\
								\
	off = (unsigned long)p % sizeof(u32);			\
	bitoff = BITOFF_CAL(sizeof(type), off);			\
	p -= off;						\
	old <<= bitoff;						\
	new <<= bitoff;						\
	prev_mask = (u32)(type)-1 << bitoff;			\
								\
	__asm__ __volatile__(					\
	br							\
"1:	lwarx   %0,0,%3\n"					\
"	and	%1,%0,%6\n"					\
"	cmpw	0,%1,%4\n"					\
"	bne-	2f\n"						\
"	andc	%1,%0,%6\n"					\
"	or	%1,%1,%5\n"					\
"	stwcx.  %1,0,%3\n"					\
"	bne-    1b\n"						\
	br2							\
	"\n"							\
"2:"								\
	: "=&r" (prev), "=&r" (tmp), "+m" (*(u32*)p)		\
	: "r" (p), "r" (old), "r" (new), "r" (prev_mask)	\
	: "cc", cl);						\
								\
	return prev >> bitoff;					\
}

/*
 * Atomic exchange
 *
 * Changes the memory location '*p' to be val and returns
 * the previous value stored there.
 */

XCHG_GEN(u8, _local, "memory");
XCHG_GEN(u8, _relaxed, "cc");
XCHG_GEN(u16, _local, "memory");
XCHG_GEN(u16, _relaxed, "cc");

static __always_inline unsigned long
__xchg_u32_local(volatile void *p, unsigned long val)
{
	unsigned long prev;

	__asm__ __volatile__(
"1:	lwarx	%0,0,%2 \n"
"	stwcx.	%3,0,%2 \n\
	bne-	1b"
	: "=&r" (prev), "+m" (*(volatile unsigned int *)p)
	: "r" (p), "r" (val)
	: "cc", "memory");

	return prev;
}

static __always_inline unsigned long
__xchg_u32_relaxed(u32 *p, unsigned long val)
{
	unsigned long prev;

	__asm__ __volatile__(
"1:	lwarx	%0,0,%2\n"
"	stwcx.	%3,0,%2\n"
"	bne-	1b"
	: "=&r" (prev), "+m" (*p)
	: "r" (p), "r" (val)
	: "cc");

	return prev;
}

#ifdef CONFIG_PPC64
static __always_inline unsigned long
__xchg_u64_local(volatile void *p, unsigned long val)
{
	unsigned long prev;

	__asm__ __volatile__(
"1:	ldarx	%0,0,%2 \n"
"	stdcx.	%3,0,%2 \n\
	bne-	1b"
	: "=&r" (prev), "+m" (*(volatile unsigned long *)p)
	: "r" (p), "r" (val)
	: "cc", "memory");

	return prev;
}

static __always_inline unsigned long
__xchg_u64_relaxed(u64 *p, unsigned long val)
{
	unsigned long prev;

	__asm__ __volatile__(
"1:	ldarx	%0,0,%2\n"
"	stdcx.	%3,0,%2\n"
"	bne-	1b"
	: "=&r" (prev), "+m" (*p)
	: "r" (p), "r" (val)
	: "cc");

	return prev;
}
#endif

static __always_inline unsigned long
__xchg_local(void *ptr, unsigned long x, unsigned int size)
{
	switch (size) {
	case 1:
		return __xchg_u8_local(ptr, x);
	case 2:
		return __xchg_u16_local(ptr, x);
	case 4:
		return __xchg_u32_local(ptr, x);
#ifdef CONFIG_PPC64
	case 8:
		return __xchg_u64_local(ptr, x);
#endif
	}
	BUILD_BUG_ON_MSG(1, "Unsupported size for __xchg");
	return x;
}

static __always_inline unsigned long
__xchg_relaxed(void *ptr, unsigned long x, unsigned int size)
{
	switch (size) {
	case 1:
		return __xchg_u8_relaxed(ptr, x);
	case 2:
		return __xchg_u16_relaxed(ptr, x);
	case 4:
		return __xchg_u32_relaxed(ptr, x);
#ifdef CONFIG_PPC64
	case 8:
		return __xchg_u64_relaxed(ptr, x);
#endif
	}
	BUILD_BUG_ON_MSG(1, "Unsupported size for __xchg_local");
	return x;
}
#define arch_xchg_local(ptr,x)						     \
  ({									     \
     __typeof__(*(ptr)) _x_ = (x);					     \
     (__typeof__(*(ptr))) __xchg_local((ptr),				     \
     		(unsigned long)_x_, sizeof(*(ptr))); 			     \
  })

#define arch_xchg_relaxed(ptr, x)					\
({									\
	__typeof__(*(ptr)) _x_ = (x);					\
	(__typeof__(*(ptr))) __xchg_relaxed((ptr),			\
			(unsigned long)_x_, sizeof(*(ptr)));		\
})
/*
 * Compare and exchange - if *p == old, set it to new,
 * and return the old value of *p.
 */

CMPXCHG_GEN(u8, , PPC_ATOMIC_ENTRY_BARRIER, PPC_ATOMIC_EXIT_BARRIER, "memory");
CMPXCHG_GEN(u8, _local, , , "memory");
CMPXCHG_GEN(u8, _acquire, , PPC_ACQUIRE_BARRIER, "memory");
CMPXCHG_GEN(u8, _relaxed, , , "cc");
CMPXCHG_GEN(u16, , PPC_ATOMIC_ENTRY_BARRIER, PPC_ATOMIC_EXIT_BARRIER, "memory");
CMPXCHG_GEN(u16, _local, , , "memory");
CMPXCHG_GEN(u16, _acquire, , PPC_ACQUIRE_BARRIER, "memory");
CMPXCHG_GEN(u16, _relaxed, , , "cc");

static __always_inline unsigned long
__cmpxchg_u32(volatile unsigned int *p, unsigned long old, unsigned long new)
{
	unsigned int prev;

	__asm__ __volatile__ (
	PPC_ATOMIC_ENTRY_BARRIER
"1:	lwarx	%0,0,%2		# __cmpxchg_u32\n\
	cmpw	0,%0,%3\n\
	bne-	2f\n"
"	stwcx.	%4,0,%2\n\
	bne-	1b"
	PPC_ATOMIC_EXIT_BARRIER
	"\n\
2:"
	: "=&r" (prev), "+m" (*p)
	: "r" (p), "r" (old), "r" (new)
	: "cc", "memory");

	return prev;
}

static __always_inline unsigned long
__cmpxchg_u32_local(volatile unsigned int *p, unsigned long old,
			unsigned long new)
{
	unsigned int prev;

	__asm__ __volatile__ (
"1:	lwarx	%0,0,%2		# __cmpxchg_u32\n\
	cmpw	0,%0,%3\n\
	bne-	2f\n"
"	stwcx.	%4,0,%2\n\
	bne-	1b"
	"\n\
2:"
	: "=&r" (prev), "+m" (*p)
	: "r" (p), "r" (old), "r" (new)
	: "cc", "memory");

	return prev;
}

static __always_inline unsigned long
__cmpxchg_u32_relaxed(u32 *p, unsigned long old, unsigned long new)
{
	unsigned long prev;

	__asm__ __volatile__ (
"1:	lwarx	%0,0,%2		# __cmpxchg_u32_relaxed\n"
"	cmpw	0,%0,%3\n"
"	bne-	2f\n"
"	stwcx.	%4,0,%2\n"
"	bne-	1b\n"
"2:"
	: "=&r" (prev), "+m" (*p)
	: "r" (p), "r" (old), "r" (new)
	: "cc");

	return prev;
}

/*
 * cmpxchg family don't have order guarantee if cmp part fails, therefore we
 * can avoid superfluous barriers if we use assembly code to implement
 * cmpxchg() and cmpxchg_acquire(), however we don't do the similar for
 * cmpxchg_release() because that will result in putting a barrier in the
 * middle of a ll/sc loop, which is probably a bad idea. For example, this
 * might cause the conditional store more likely to fail.
 */
static __always_inline unsigned long
__cmpxchg_u32_acquire(u32 *p, unsigned long old, unsigned long new)
{
	unsigned long prev;

	__asm__ __volatile__ (
"1:	lwarx	%0,0,%2		# __cmpxchg_u32_acquire\n"
"	cmpw	0,%0,%3\n"
"	bne-	2f\n"
"	stwcx.	%4,0,%2\n"
"	bne-	1b\n"
	PPC_ACQUIRE_BARRIER
	"\n"
"2:"
	: "=&r" (prev), "+m" (*p)
	: "r" (p), "r" (old), "r" (new)
	: "cc", "memory");

	return prev;
}

#ifdef CONFIG_PPC64
static __always_inline unsigned long
__cmpxchg_u64(volatile unsigned long *p, unsigned long old, unsigned long new)
{
	unsigned long prev;

	__asm__ __volatile__ (
	PPC_ATOMIC_ENTRY_BARRIER
"1:	ldarx	%0,0,%2		# __cmpxchg_u64\n\
	cmpd	0,%0,%3\n\
	bne-	2f\n\
	stdcx.	%4,0,%2\n\
	bne-	1b"
	PPC_ATOMIC_EXIT_BARRIER
	"\n\
2:"
	: "=&r" (prev), "+m" (*p)
	: "r" (p), "r" (old), "r" (new)
	: "cc", "memory");

	return prev;
}

static __always_inline unsigned long
__cmpxchg_u64_local(volatile unsigned long *p, unsigned long old,
			unsigned long new)
{
	unsigned long prev;

	__asm__ __volatile__ (
"1:	ldarx	%0,0,%2		# __cmpxchg_u64\n\
	cmpd	0,%0,%3\n\
	bne-	2f\n\
	stdcx.	%4,0,%2\n\
	bne-	1b"
	"\n\
2:"
	: "=&r" (prev), "+m" (*p)
	: "r" (p), "r" (old), "r" (new)
	: "cc", "memory");

	return prev;
}

static __always_inline unsigned long
__cmpxchg_u64_relaxed(u64 *p, unsigned long old, unsigned long new)
{
	unsigned long prev;

	__asm__ __volatile__ (
"1:	ldarx	%0,0,%2		# __cmpxchg_u64_relaxed\n"
"	cmpd	0,%0,%3\n"
"	bne-	2f\n"
"	stdcx.	%4,0,%2\n"
"	bne-	1b\n"
"2:"
	: "=&r" (prev), "+m" (*p)
	: "r" (p), "r" (old), "r" (new)
	: "cc");

	return prev;
}

static __always_inline unsigned long
__cmpxchg_u64_acquire(u64 *p, unsigned long old, unsigned long new)
{
	unsigned long prev;

	__asm__ __volatile__ (
"1:	ldarx	%0,0,%2		# __cmpxchg_u64_acquire\n"
"	cmpd	0,%0,%3\n"
"	bne-	2f\n"
"	stdcx.	%4,0,%2\n"
"	bne-	1b\n"
	PPC_ACQUIRE_BARRIER
	"\n"
"2:"
	: "=&r" (prev), "+m" (*p)
	: "r" (p), "r" (old), "r" (new)
	: "cc", "memory");

	return prev;
}
#endif

static __always_inline unsigned long
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,
	  unsigned int size)
{
	switch (size) {
	case 1:
		return __cmpxchg_u8(ptr, old, new);
	case 2:
		return __cmpxchg_u16(ptr, old, new);
	case 4:
		return __cmpxchg_u32(ptr, old, new);
#ifdef CONFIG_PPC64
	case 8:
		return __cmpxchg_u64(ptr, old, new);
#endif
	}
	BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg");
	return old;
}

static __always_inline unsigned long
__cmpxchg_local(void *ptr, unsigned long old, unsigned long new,
	  unsigned int size)
{
	switch (size) {
	case 1:
		return __cmpxchg_u8_local(ptr, old, new);
	case 2:
		return __cmpxchg_u16_local(ptr, old, new);
	case 4:
		return __cmpxchg_u32_local(ptr, old, new);
#ifdef CONFIG_PPC64
	case 8:
		return __cmpxchg_u64_local(ptr, old, new);
#endif
	}
	BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_local");
	return old;
}

static __always_inline unsigned long
__cmpxchg_relaxed(void *ptr, unsigned long old, unsigned long new,
		  unsigned int size)
{
	switch (size) {
	case 1:
		return __cmpxchg_u8_relaxed(ptr, old, new);
	case 2:
		return __cmpxchg_u16_relaxed(ptr, old, new);
	case 4:
		return __cmpxchg_u32_relaxed(ptr, old, new);
#ifdef CONFIG_PPC64
	case 8:
		return __cmpxchg_u64_relaxed(ptr, old, new);
#endif
	}
	BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_relaxed");
	return old;
}

static __always_inline unsigned long
__cmpxchg_acquire(void *ptr, unsigned long old, unsigned long new,
		  unsigned int size)
{
	switch (size) {
	case 1:
		return __cmpxchg_u8_acquire(ptr, old, new);
	case 2:
		return __cmpxchg_u16_acquire(ptr, old, new);
	case 4:
		return __cmpxchg_u32_acquire(ptr, old, new);
#ifdef CONFIG_PPC64
	case 8:
		return __cmpxchg_u64_acquire(ptr, old, new);
#endif
	}
	BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_acquire");
	return old;
}
#define arch_cmpxchg(ptr, o, n)						 \
  ({									 \
     __typeof__(*(ptr)) _o_ = (o);					 \
     __typeof__(*(ptr)) _n_ = (n);					 \
     (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,		 \
				    (unsigned long)_n_, sizeof(*(ptr))); \
  })


#define arch_cmpxchg_local(ptr, o, n)					 \
  ({									 \
     __typeof__(*(ptr)) _o_ = (o);					 \
     __typeof__(*(ptr)) _n_ = (n);					 \
     (__typeof__(*(ptr))) __cmpxchg_local((ptr), (unsigned long)_o_,	 \
				    (unsigned long)_n_, sizeof(*(ptr))); \
  })

#define arch_cmpxchg_relaxed(ptr, o, n)					\
({									\
	__typeof__(*(ptr)) _o_ = (o);					\
	__typeof__(*(ptr)) _n_ = (n);					\
	(__typeof__(*(ptr))) __cmpxchg_relaxed((ptr),			\
			(unsigned long)_o_, (unsigned long)_n_,		\
			sizeof(*(ptr)));				\
})

#define arch_cmpxchg_acquire(ptr, o, n)					\
({									\
	__typeof__(*(ptr)) _o_ = (o);					\
	__typeof__(*(ptr)) _n_ = (n);					\
	(__typeof__(*(ptr))) __cmpxchg_acquire((ptr),			\
			(unsigned long)_o_, (unsigned long)_n_,		\
			sizeof(*(ptr)));				\
})
#ifdef CONFIG_PPC64
#define arch_cmpxchg64(ptr, o, n)					\
  ({									\
	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
	arch_cmpxchg((ptr), (o), (n));					\
  })
#define arch_cmpxchg64_local(ptr, o, n)					\
  ({									\
	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
	arch_cmpxchg_local((ptr), (o), (n));				\
  })
#define arch_cmpxchg64_relaxed(ptr, o, n)				\
({									\
	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
	arch_cmpxchg_relaxed((ptr), (o), (n));				\
})
#define arch_cmpxchg64_acquire(ptr, o, n)				\
({									\
	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
	arch_cmpxchg_acquire((ptr), (o), (n));				\
})
#else
#include <asm-generic/cmpxchg-local.h>
#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
#endif

#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_CMPXCHG_H_ */