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Diffstat (limited to 'arch/arm64/include/asm/atomic.h')
-rw-r--r-- | arch/arm64/include/asm/atomic.h | 305 |
1 files changed, 305 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/atomic.h b/arch/arm64/include/asm/atomic.h new file mode 100644 index 000000000000..407717ba060e --- /dev/null +++ b/arch/arm64/include/asm/atomic.h @@ -0,0 +1,305 @@ +/* + * 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) (*(volatile int *)&(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. + */ +static inline void atomic_add(int i, atomic_t *v) +{ + unsigned long tmp; + int result; + + asm volatile("// atomic_add\n" +"1: ldxr %w0, [%3]\n" +" add %w0, %w0, %w4\n" +" stxr %w1, %w0, [%3]\n" +" cbnz %w1, 1b" + : "=&r" (result), "=&r" (tmp), "+o" (v->counter) + : "r" (&v->counter), "Ir" (i) + : "cc"); +} + +static inline int atomic_add_return(int i, atomic_t *v) +{ + unsigned long tmp; + int result; + + asm volatile("// atomic_add_return\n" +"1: ldaxr %w0, [%3]\n" +" add %w0, %w0, %w4\n" +" stlxr %w1, %w0, [%3]\n" +" cbnz %w1, 1b" + : "=&r" (result), "=&r" (tmp), "+o" (v->counter) + : "r" (&v->counter), "Ir" (i) + : "cc"); + + return result; +} + +static inline void atomic_sub(int i, atomic_t *v) +{ + unsigned long tmp; + int result; + + asm volatile("// atomic_sub\n" +"1: ldxr %w0, [%3]\n" +" sub %w0, %w0, %w4\n" +" stxr %w1, %w0, [%3]\n" +" cbnz %w1, 1b" + : "=&r" (result), "=&r" (tmp), "+o" (v->counter) + : "r" (&v->counter), "Ir" (i) + : "cc"); +} + +static inline int atomic_sub_return(int i, atomic_t *v) +{ + unsigned long tmp; + int result; + + asm volatile("// atomic_sub_return\n" +"1: ldaxr %w0, [%3]\n" +" sub %w0, %w0, %w4\n" +" stlxr %w1, %w0, [%3]\n" +" cbnz %w1, 1b" + : "=&r" (result), "=&r" (tmp), "+o" (v->counter) + : "r" (&v->counter), "Ir" (i) + : "cc"); + + return result; +} + +static inline int atomic_cmpxchg(atomic_t *ptr, int old, int new) +{ + unsigned long tmp; + int oldval; + + asm volatile("// atomic_cmpxchg\n" +"1: ldaxr %w1, [%3]\n" +" cmp %w1, %w4\n" +" b.ne 2f\n" +" stlxr %w0, %w5, [%3]\n" +" cbnz %w0, 1b\n" +"2:" + : "=&r" (tmp), "=&r" (oldval), "+o" (ptr->counter) + : "r" (&ptr->counter), "Ir" (old), "r" (new) + : "cc"); + + return oldval; +} + +static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr) +{ + unsigned long tmp, tmp2; + + asm volatile("// atomic_clear_mask\n" +"1: ldxr %0, [%3]\n" +" bic %0, %0, %4\n" +" stxr %w1, %0, [%3]\n" +" cbnz %w1, 1b" + : "=&r" (tmp), "=&r" (tmp2), "+o" (*addr) + : "r" (addr), "Ir" (mask) + : "cc"); +} + +#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) + +#define smp_mb__before_atomic_dec() smp_mb() +#define smp_mb__after_atomic_dec() smp_mb() +#define smp_mb__before_atomic_inc() smp_mb() +#define smp_mb__after_atomic_inc() smp_mb() + +/* + * 64-bit atomic operations. + */ +#define ATOMIC64_INIT(i) { (i) } + +#define atomic64_read(v) (*(volatile long long *)&(v)->counter) +#define atomic64_set(v,i) (((v)->counter) = (i)) + +static inline void atomic64_add(u64 i, atomic64_t *v) +{ + long result; + unsigned long tmp; + + asm volatile("// atomic64_add\n" +"1: ldxr %0, [%3]\n" +" add %0, %0, %4\n" +" stxr %w1, %0, [%3]\n" +" cbnz %w1, 1b" + : "=&r" (result), "=&r" (tmp), "+o" (v->counter) + : "r" (&v->counter), "Ir" (i) + : "cc"); +} + +static inline long atomic64_add_return(long i, atomic64_t *v) +{ + long result; + unsigned long tmp; + + asm volatile("// atomic64_add_return\n" +"1: ldaxr %0, [%3]\n" +" add %0, %0, %4\n" +" stlxr %w1, %0, [%3]\n" +" cbnz %w1, 1b" + : "=&r" (result), "=&r" (tmp), "+o" (v->counter) + : "r" (&v->counter), "Ir" (i) + : "cc"); + + return result; +} + +static inline void atomic64_sub(u64 i, atomic64_t *v) +{ + long result; + unsigned long tmp; + + asm volatile("// atomic64_sub\n" +"1: ldxr %0, [%3]\n" +" sub %0, %0, %4\n" +" stxr %w1, %0, [%3]\n" +" cbnz %w1, 1b" + : "=&r" (result), "=&r" (tmp), "+o" (v->counter) + : "r" (&v->counter), "Ir" (i) + : "cc"); +} + +static inline long atomic64_sub_return(long i, atomic64_t *v) +{ + long result; + unsigned long tmp; + + asm volatile("// atomic64_sub_return\n" +"1: ldaxr %0, [%3]\n" +" sub %0, %0, %4\n" +" stlxr %w1, %0, [%3]\n" +" cbnz %w1, 1b" + : "=&r" (result), "=&r" (tmp), "+o" (v->counter) + : "r" (&v->counter), "Ir" (i) + : "cc"); + + return result; +} + +static inline long atomic64_cmpxchg(atomic64_t *ptr, long old, long new) +{ + long oldval; + unsigned long res; + + asm volatile("// atomic64_cmpxchg\n" +"1: ldaxr %1, [%3]\n" +" cmp %1, %4\n" +" b.ne 2f\n" +" stlxr %w0, %5, [%3]\n" +" cbnz %w0, 1b\n" +"2:" + : "=&r" (res), "=&r" (oldval), "+o" (ptr->counter) + : "r" (&ptr->counter), "Ir" (old), "r" (new) + : "cc"); + + 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: ldaxr %0, [%3]\n" +" subs %0, %0, #1\n" +" b.mi 2f\n" +" stlxr %w1, %0, [%3]\n" +" cbnz %w1, 1b\n" +"2:" + : "=&r" (result), "=&r" (tmp), "+o" (v->counter) + : "r" (&v->counter) + : "cc"); + + 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 |