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Diffstat (limited to 'kernel/arch/arm64/include/asm/atomic.h')
| -rw-r--r-- | kernel/arch/arm64/include/asm/atomic.h | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/kernel/arch/arm64/include/asm/atomic.h b/kernel/arch/arm64/include/asm/atomic.h new file mode 100644 index 000000000..7047051de --- /dev/null +++ b/kernel/arch/arm64/include/asm/atomic.h @@ -0,0 +1,256 @@ +/* + * 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_H +#define __ASM_ATOMIC_H + +#include <linux/compiler.h> +#include <linux/types.h> + +#include <asm/barrier.h> +#include <asm/cmpxchg.h> + +#define ATOMIC_INIT(i) { (i) } + +#ifdef __KERNEL__ + +/* + * On ARM, ordinary assignment (str instruction) doesn't clear the local + * strex/ldrex monitor on some implementations. The reason we can use it for + * atomic_set() is the clrex or dummy strex done on every exception return. + */ +#define atomic_read(v) ACCESS_ONCE((v)->counter) +#define atomic_set(v,i) (((v)->counter) = (i)) + +/* + * 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. + */ + +#define ATOMIC_OP(op, asm_op) \ +static inline void 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) \ +static inline int 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) + +#undef ATOMIC_OPS +#undef ATOMIC_OP_RETURN +#undef ATOMIC_OP + +static inline int 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 atomic_xchg(v, new) (xchg(&((v)->counter), new)) + +static inline int __atomic_add_unless(atomic_t *v, int a, int u) +{ + int c, old; + + c = atomic_read(v); + while (c != u && (old = atomic_cmpxchg((v), c, c + a)) != c) + c = old; + return c; +} + +#define atomic_inc(v) atomic_add(1, v) +#define atomic_dec(v) atomic_sub(1, v) + +#define atomic_inc_and_test(v) (atomic_add_return(1, v) == 0) +#define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0) +#define atomic_inc_return(v) (atomic_add_return(1, v)) +#define atomic_dec_return(v) (atomic_sub_return(1, v)) +#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0) + +#define atomic_add_negative(i,v) (atomic_add_return(i, v) < 0) + +/* + * 64-bit atomic operations. + */ +#define ATOMIC64_INIT(i) { (i) } + +#define atomic64_read(v) ACCESS_ONCE((v)->counter) +#define atomic64_set(v,i) (((v)->counter) = (i)) + +#define ATOMIC64_OP(op, asm_op) \ +static inline void 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) \ +static inline long 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) + +#undef ATOMIC64_OPS +#undef ATOMIC64_OP_RETURN +#undef ATOMIC64_OP + +static inline long 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; +} + +#define atomic64_xchg(v, new) (xchg(&((v)->counter), new)) + +static inline long 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; +} + +static inline int atomic64_add_unless(atomic64_t *v, long a, long u) +{ + long c, old; + + c = atomic64_read(v); + while (c != u && (old = atomic64_cmpxchg((v), c, c + a)) != c) + c = old; + + return c != u; +} + +#define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0) +#define atomic64_inc(v) atomic64_add(1LL, (v)) +#define atomic64_inc_return(v) atomic64_add_return(1LL, (v)) +#define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0) +#define atomic64_sub_and_test(a, v) (atomic64_sub_return((a), (v)) == 0) +#define atomic64_dec(v) atomic64_sub(1LL, (v)) +#define atomic64_dec_return(v) atomic64_sub_return(1LL, (v)) +#define atomic64_dec_and_test(v) (atomic64_dec_return((v)) == 0) +#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1LL, 0LL) + +#endif +#endif |