diff options
Diffstat (limited to 'arch/x86/include/asm/atomic64_32.h')
| -rw-r--r-- | arch/x86/include/asm/atomic64_32.h | 184 |
1 files changed, 115 insertions, 69 deletions
diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h index 3486d91b8595..ab838205c1c6 100644 --- a/arch/x86/include/asm/atomic64_32.h +++ b/arch/x86/include/asm/atomic64_32.h @@ -14,6 +14,32 @@ typedef struct { #define ATOMIC64_INIT(val) { (val) } +/* + * Read an atomic64_t non-atomically. + * + * This is intended to be used in cases where a subsequent atomic operation + * will handle the torn value, and can be used to prime the first iteration + * of unconditional try_cmpxchg() loops, e.g.: + * + * s64 val = arch_atomic64_read_nonatomic(v); + * do { } while (!arch_atomic64_try_cmpxchg(v, &val, val OP i); + * + * This is NOT safe to use where the value is not always checked by a + * subsequent atomic operation, such as in conditional try_cmpxchg() loops + * that can break before the atomic operation, e.g.: + * + * s64 val = arch_atomic64_read_nonatomic(v); + * do { + * if (condition(val)) + * break; + * } while (!arch_atomic64_try_cmpxchg(v, &val, val OP i); + */ +static __always_inline s64 arch_atomic64_read_nonatomic(const atomic64_t *v) +{ + /* See comment in arch_atomic_read(). */ + return __READ_ONCE(v->counter); +} + #define __ATOMIC64_DECL(sym) void atomic64_##sym(atomic64_t *, ...) #ifndef ATOMIC64_EXPORT #define ATOMIC64_DECL_ONE __ATOMIC64_DECL @@ -22,16 +48,20 @@ typedef struct { ATOMIC64_EXPORT(atomic64_##sym) #endif -#ifdef CONFIG_X86_CMPXCHG64 -#define __alternative_atomic64(f, g, out, in...) \ - asm volatile("call %P[func]" \ - : out : [func] "i" (atomic64_##g##_cx8), ## in) +#ifdef CONFIG_X86_CX8 +#define __alternative_atomic64(f, g, out, in, clobbers...) \ + asm volatile("call %c[func]" \ + : ALT_OUTPUT_SP(out) \ + : [func] "i" (atomic64_##g##_cx8) \ + COMMA(in) \ + : clobbers) #define ATOMIC64_DECL(sym) ATOMIC64_DECL_ONE(sym##_cx8) #else -#define __alternative_atomic64(f, g, out, in...) \ - alternative_call(atomic64_##f##_386, atomic64_##g##_cx8, \ - X86_FEATURE_CX8, ASM_OUTPUT2(out), ## in) +#define __alternative_atomic64(f, g, out, in, clobbers...) \ + alternative_call(atomic64_##f##_386, atomic64_##g##_cx8, \ + X86_FEATURE_CX8, ASM_OUTPUT(out), \ + ASM_INPUT(in), clobbers) #define ATOMIC64_DECL(sym) ATOMIC64_DECL_ONE(sym##_cx8); \ ATOMIC64_DECL_ONE(sym##_386) @@ -42,8 +72,8 @@ ATOMIC64_DECL_ONE(inc_386); ATOMIC64_DECL_ONE(dec_386); #endif -#define alternative_atomic64(f, out, in...) \ - __alternative_atomic64(f, f, ASM_OUTPUT2(out), ## in) +#define alternative_atomic64(f, out, in, clobbers...) \ + __alternative_atomic64(f, f, ASM_OUTPUT(out), ASM_INPUT(in), clobbers) ATOMIC64_DECL(read); ATOMIC64_DECL(set); @@ -61,20 +91,27 @@ ATOMIC64_DECL(add_unless); #undef __ATOMIC64_DECL #undef ATOMIC64_EXPORT -static __always_inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n) +static __always_inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new) { - return arch_cmpxchg64(&v->counter, o, n); + return arch_cmpxchg64(&v->counter, old, new); } #define arch_atomic64_cmpxchg arch_atomic64_cmpxchg +static __always_inline bool arch_atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 new) +{ + return arch_try_cmpxchg64(&v->counter, old, new); +} +#define arch_atomic64_try_cmpxchg arch_atomic64_try_cmpxchg + static __always_inline s64 arch_atomic64_xchg(atomic64_t *v, s64 n) { s64 o; unsigned high = (unsigned)(n >> 32); unsigned low = (unsigned)n; - alternative_atomic64(xchg, "=&A" (o), - "S" (v), "b" (low), "c" (high) - : "memory"); + alternative_atomic64(xchg, + "=&A" (o), + ASM_INPUT("S" (v), "b" (low), "c" (high)), + "memory"); return o; } #define arch_atomic64_xchg arch_atomic64_xchg @@ -83,23 +120,25 @@ static __always_inline void arch_atomic64_set(atomic64_t *v, s64 i) { unsigned high = (unsigned)(i >> 32); unsigned low = (unsigned)i; - alternative_atomic64(set, /* no output */, - "S" (v), "b" (low), "c" (high) - : "eax", "edx", "memory"); + alternative_atomic64(set, + /* no output */, + ASM_INPUT("S" (v), "b" (low), "c" (high)), + "eax", "edx", "memory"); } static __always_inline s64 arch_atomic64_read(const atomic64_t *v) { s64 r; - alternative_atomic64(read, "=&A" (r), "c" (v) : "memory"); + alternative_atomic64(read, "=&A" (r), "c" (v), "memory"); return r; } static __always_inline s64 arch_atomic64_add_return(s64 i, atomic64_t *v) { alternative_atomic64(add_return, - ASM_OUTPUT2("+A" (i), "+c" (v)), - ASM_NO_INPUT_CLOBBER("memory")); + ASM_OUTPUT("+A" (i), "+c" (v)), + /* no input */, + "memory"); return i; } #define arch_atomic64_add_return arch_atomic64_add_return @@ -107,8 +146,9 @@ static __always_inline s64 arch_atomic64_add_return(s64 i, atomic64_t *v) static __always_inline s64 arch_atomic64_sub_return(s64 i, atomic64_t *v) { alternative_atomic64(sub_return, - ASM_OUTPUT2("+A" (i), "+c" (v)), - ASM_NO_INPUT_CLOBBER("memory")); + ASM_OUTPUT("+A" (i), "+c" (v)), + /* no input */, + "memory"); return i; } #define arch_atomic64_sub_return arch_atomic64_sub_return @@ -116,8 +156,10 @@ static __always_inline s64 arch_atomic64_sub_return(s64 i, atomic64_t *v) static __always_inline s64 arch_atomic64_inc_return(atomic64_t *v) { s64 a; - alternative_atomic64(inc_return, "=&A" (a), - "S" (v) : "memory", "ecx"); + alternative_atomic64(inc_return, + "=&A" (a), + "S" (v), + "memory", "ecx"); return a; } #define arch_atomic64_inc_return arch_atomic64_inc_return @@ -125,39 +167,45 @@ static __always_inline s64 arch_atomic64_inc_return(atomic64_t *v) static __always_inline s64 arch_atomic64_dec_return(atomic64_t *v) { s64 a; - alternative_atomic64(dec_return, "=&A" (a), - "S" (v) : "memory", "ecx"); + alternative_atomic64(dec_return, + "=&A" (a), + "S" (v), + "memory", "ecx"); return a; } #define arch_atomic64_dec_return arch_atomic64_dec_return -static __always_inline s64 arch_atomic64_add(s64 i, atomic64_t *v) +static __always_inline void arch_atomic64_add(s64 i, atomic64_t *v) { __alternative_atomic64(add, add_return, - ASM_OUTPUT2("+A" (i), "+c" (v)), - ASM_NO_INPUT_CLOBBER("memory")); - return i; + ASM_OUTPUT("+A" (i), "+c" (v)), + /* no input */, + "memory"); } -static __always_inline s64 arch_atomic64_sub(s64 i, atomic64_t *v) +static __always_inline void arch_atomic64_sub(s64 i, atomic64_t *v) { __alternative_atomic64(sub, sub_return, - ASM_OUTPUT2("+A" (i), "+c" (v)), - ASM_NO_INPUT_CLOBBER("memory")); - return i; + ASM_OUTPUT("+A" (i), "+c" (v)), + /* no input */, + "memory"); } static __always_inline void arch_atomic64_inc(atomic64_t *v) { - __alternative_atomic64(inc, inc_return, /* no output */, - "S" (v) : "memory", "eax", "ecx", "edx"); + __alternative_atomic64(inc, inc_return, + /* no output */, + "S" (v), + "memory", "eax", "ecx", "edx"); } #define arch_atomic64_inc arch_atomic64_inc static __always_inline void arch_atomic64_dec(atomic64_t *v) { - __alternative_atomic64(dec, dec_return, /* no output */, - "S" (v) : "memory", "eax", "ecx", "edx"); + __alternative_atomic64(dec, dec_return, + /* no output */, + "S" (v), + "memory", "eax", "ecx", "edx"); } #define arch_atomic64_dec arch_atomic64_dec @@ -166,8 +214,9 @@ static __always_inline int arch_atomic64_add_unless(atomic64_t *v, s64 a, s64 u) unsigned low = (unsigned)u; unsigned high = (unsigned)(u >> 32); alternative_atomic64(add_unless, - ASM_OUTPUT2("+A" (a), "+c" (low), "+D" (high)), - "S" (v) : "memory"); + ASM_OUTPUT("+A" (a), "+c" (low), "+D" (high)), + "S" (v), + "memory"); return (int)a; } #define arch_atomic64_add_unless arch_atomic64_add_unless @@ -175,8 +224,10 @@ static __always_inline int arch_atomic64_add_unless(atomic64_t *v, s64 a, s64 u) static __always_inline int arch_atomic64_inc_not_zero(atomic64_t *v) { int r; - alternative_atomic64(inc_not_zero, "=&a" (r), - "S" (v) : "ecx", "edx", "memory"); + alternative_atomic64(inc_not_zero, + "=&a" (r), + "S" (v), + "ecx", "edx", "memory"); return r; } #define arch_atomic64_inc_not_zero arch_atomic64_inc_not_zero @@ -184,8 +235,10 @@ static __always_inline int arch_atomic64_inc_not_zero(atomic64_t *v) static __always_inline s64 arch_atomic64_dec_if_positive(atomic64_t *v) { s64 r; - alternative_atomic64(dec_if_positive, "=&A" (r), - "S" (v) : "ecx", "memory"); + alternative_atomic64(dec_if_positive, + "=&A" (r), + "S" (v), + "ecx", "memory"); return r; } #define arch_atomic64_dec_if_positive arch_atomic64_dec_if_positive @@ -195,69 +248,62 @@ static __always_inline s64 arch_atomic64_dec_if_positive(atomic64_t *v) static __always_inline void arch_atomic64_and(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c & i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val & i)); } static __always_inline s64 arch_atomic64_fetch_and(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c & i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val & i)); - return old; + return val; } #define arch_atomic64_fetch_and arch_atomic64_fetch_and static __always_inline void arch_atomic64_or(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c | i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val | i)); } static __always_inline s64 arch_atomic64_fetch_or(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c | i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val | i)); - return old; + return val; } #define arch_atomic64_fetch_or arch_atomic64_fetch_or static __always_inline void arch_atomic64_xor(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c ^ i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val ^ i)); } static __always_inline s64 arch_atomic64_fetch_xor(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c ^ i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val ^ i)); - return old; + return val; } #define arch_atomic64_fetch_xor arch_atomic64_fetch_xor static __always_inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c + i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val + i)); - return old; + return val; } #define arch_atomic64_fetch_add arch_atomic64_fetch_add |