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Diffstat (limited to 'arch/arm64/include/asm/atomic_ll_sc.h')
| -rw-r--r-- | arch/arm64/include/asm/atomic_ll_sc.h | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/atomic_ll_sc.h b/arch/arm64/include/asm/atomic_ll_sc.h new file mode 100644 index 000000000000..66e992a58f6b --- /dev/null +++ b/arch/arm64/include/asm/atomic_ll_sc.h @@ -0,0 +1,215 @@ +/* + * Based on arch/arm/include/asm/atomic.h + * + * Copyright (C) 1996 Russell King. + * Copyright (C) 2002 Deep Blue Solutions Ltd. + * Copyright (C) 2012 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef __ASM_ATOMIC_LL_SC_H +#define __ASM_ATOMIC_LL_SC_H + +/* + * AArch64 UP and SMP safe atomic ops. We use load exclusive and + * store exclusive to ensure that these are atomic. We may loop + * to ensure that the update happens. + * + * NOTE: these functions do *not* follow the PCS and must explicitly + * save any clobbered registers other than x0 (regardless of return + * value). This is achieved through -fcall-saved-* compiler flags for + * this file, which unfortunately don't work on a per-function basis + * (the optimize attribute silently ignores these options). + */ + +#ifndef __LL_SC_INLINE +#define __LL_SC_INLINE static inline +#endif + +#ifndef __LL_SC_PREFIX +#define __LL_SC_PREFIX(x) x +#endif + +#define ATOMIC_OP(op, asm_op) \ +__LL_SC_INLINE void \ +__LL_SC_PREFIX(atomic_##op(int i, atomic_t *v)) \ +{ \ + unsigned long tmp; \ + int result; \ + \ + asm volatile("// atomic_" #op "\n" \ +"1: ldxr %w0, %2\n" \ +" " #asm_op " %w0, %w0, %w3\n" \ +" stxr %w1, %w0, %2\n" \ +" cbnz %w1, 1b" \ + : "=&r" (result), "=&r" (tmp), "+Q" (v->counter) \ + : "Ir" (i)); \ +} \ + +#define ATOMIC_OP_RETURN(op, asm_op) \ +__LL_SC_INLINE int \ +__LL_SC_PREFIX(atomic_##op##_return(int i, atomic_t *v)) \ +{ \ + unsigned long tmp; \ + int result; \ + \ + asm volatile("// atomic_" #op "_return\n" \ +"1: ldxr %w0, %2\n" \ +" " #asm_op " %w0, %w0, %w3\n" \ +" stlxr %w1, %w0, %2\n" \ +" cbnz %w1, 1b" \ + : "=&r" (result), "=&r" (tmp), "+Q" (v->counter) \ + : "Ir" (i) \ + : "memory"); \ + \ + smp_mb(); \ + return result; \ +} + +#define ATOMIC_OPS(op, asm_op) \ + ATOMIC_OP(op, asm_op) \ + ATOMIC_OP_RETURN(op, asm_op) + +ATOMIC_OPS(add, add) +ATOMIC_OPS(sub, sub) + +ATOMIC_OP(and, and) +ATOMIC_OP(andnot, bic) +ATOMIC_OP(or, orr) +ATOMIC_OP(xor, eor) + +#undef ATOMIC_OPS +#undef ATOMIC_OP_RETURN +#undef ATOMIC_OP + +__LL_SC_INLINE int +__LL_SC_PREFIX(atomic_cmpxchg(atomic_t *ptr, int old, int new)) +{ + unsigned long tmp; + int oldval; + + smp_mb(); + + asm volatile("// atomic_cmpxchg\n" +"1: ldxr %w1, %2\n" +" cmp %w1, %w3\n" +" b.ne 2f\n" +" stxr %w0, %w4, %2\n" +" cbnz %w0, 1b\n" +"2:" + : "=&r" (tmp), "=&r" (oldval), "+Q" (ptr->counter) + : "Ir" (old), "r" (new) + : "cc"); + + smp_mb(); + return oldval; +} + +#define ATOMIC64_OP(op, asm_op) \ +__LL_SC_INLINE void \ +__LL_SC_PREFIX(atomic64_##op(long i, atomic64_t *v)) \ +{ \ + long result; \ + unsigned long tmp; \ + \ + asm volatile("// atomic64_" #op "\n" \ +"1: ldxr %0, %2\n" \ +" " #asm_op " %0, %0, %3\n" \ +" stxr %w1, %0, %2\n" \ +" cbnz %w1, 1b" \ + : "=&r" (result), "=&r" (tmp), "+Q" (v->counter) \ + : "Ir" (i)); \ +} \ + +#define ATOMIC64_OP_RETURN(op, asm_op) \ +__LL_SC_INLINE long \ +__LL_SC_PREFIX(atomic64_##op##_return(long i, atomic64_t *v)) \ +{ \ + long result; \ + unsigned long tmp; \ + \ + asm volatile("// atomic64_" #op "_return\n" \ +"1: ldxr %0, %2\n" \ +" " #asm_op " %0, %0, %3\n" \ +" stlxr %w1, %0, %2\n" \ +" cbnz %w1, 1b" \ + : "=&r" (result), "=&r" (tmp), "+Q" (v->counter) \ + : "Ir" (i) \ + : "memory"); \ + \ + smp_mb(); \ + return result; \ +} + +#define ATOMIC64_OPS(op, asm_op) \ + ATOMIC64_OP(op, asm_op) \ + ATOMIC64_OP_RETURN(op, asm_op) + +ATOMIC64_OPS(add, add) +ATOMIC64_OPS(sub, sub) + +ATOMIC64_OP(and, and) +ATOMIC64_OP(andnot, bic) +ATOMIC64_OP(or, orr) +ATOMIC64_OP(xor, eor) + +#undef ATOMIC64_OPS +#undef ATOMIC64_OP_RETURN +#undef ATOMIC64_OP + +__LL_SC_INLINE long +__LL_SC_PREFIX(atomic64_cmpxchg(atomic64_t *ptr, long old, long new)) +{ + long oldval; + unsigned long res; + + smp_mb(); + + asm volatile("// atomic64_cmpxchg\n" +"1: ldxr %1, %2\n" +" cmp %1, %3\n" +" b.ne 2f\n" +" stxr %w0, %4, %2\n" +" cbnz %w0, 1b\n" +"2:" + : "=&r" (res), "=&r" (oldval), "+Q" (ptr->counter) + : "Ir" (old), "r" (new) + : "cc"); + + smp_mb(); + return oldval; +} + +__LL_SC_INLINE long +__LL_SC_PREFIX(atomic64_dec_if_positive(atomic64_t *v)) +{ + long result; + unsigned long tmp; + + asm volatile("// atomic64_dec_if_positive\n" +"1: ldxr %0, %2\n" +" subs %0, %0, #1\n" +" b.mi 2f\n" +" stlxr %w1, %0, %2\n" +" cbnz %w1, 1b\n" +" dmb ish\n" +"2:" + : "=&r" (result), "=&r" (tmp), "+Q" (v->counter) + : + : "cc", "memory"); + + return result; +} + +#endif /* __ASM_ATOMIC_LL_SC_H */ |