Messages in this thread Patch in this message | | | Date | Fri, 10 Dec 2021 17:16:21 +0100 | From | Peter Zijlstra <> | Subject | [PATCH v2 3/9] atomic: Introduce atomic_{inc,dec,dec_and_test}_overflow() |
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In order to facilitate architecture support for refcount_t, introduce a number of new atomic primitives that have a uaccess style exception for overflow.
Notably:
atomic_inc_overflow(v, Label):
increment and goto Label when the old value of v is zero or negative.
atomic_dec_overflow(v, Label):
decrement and goto Label when the new value of v is zero or negative
atomic_dec_and_test_overflow(v, Label):
decrement and return true when the result is zero and goto Label when the new value of v is negative
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- include/linux/atomic/atomic-arch-fallback.h | 64 ++++++++++++++++++++++++ include/linux/atomic/atomic-instrumented.h | 65 ++++++++++++++++++++++++- include/linux/atomic/atomic-long.h | 32 +++++++++++- scripts/atomic/atomics.tbl | 3 + scripts/atomic/fallbacks/dec_and_test_overflow | 12 ++++ scripts/atomic/fallbacks/dec_overflow | 8 +++ scripts/atomic/fallbacks/inc_overflow | 8 +++ 7 files changed, 189 insertions(+), 3 deletions(-)
--- a/include/linux/atomic/atomic-arch-fallback.h +++ b/include/linux/atomic/atomic-arch-fallback.h @@ -1250,6 +1250,37 @@ arch_atomic_dec_if_positive(atomic_t *v) #define arch_atomic_dec_if_positive arch_atomic_dec_if_positive #endif +#ifndef arch_atomic_inc_overflow +#define arch_atomic_inc_overflow(_v, _label) \ +do { \ + int __old = arch_atomic_fetch_inc(_v); \ + if (unlikely(__old <= 0)) \ + goto _label; \ +} while (0) +#endif + +#ifndef arch_atomic_dec_overflow +#define arch_atomic_dec_overflow(_v, _label) \ +do { \ + int __new = arch_atomic_dec_return(_v); \ + if (unlikely(__new <= 0)) \ + goto _label; \ +} while (0) +#endif + +#ifndef arch_atomic_dec_and_test_overflow +#define arch_atomic_dec_and_test_overflow(_v, _label) \ +({ \ + bool __ret = false; \ + int __new = arch_atomic_dec_return(_v); \ + if (unlikely(__new < 0)) \ + goto _label; \ + if (unlikely(__new == 0)) \ + __ret = true; \ + __ret; \ +}) +#endif + #ifdef CONFIG_GENERIC_ATOMIC64 #include <asm-generic/atomic64.h> #endif @@ -2357,5 +2388,36 @@ arch_atomic64_dec_if_positive(atomic64_t #define arch_atomic64_dec_if_positive arch_atomic64_dec_if_positive #endif +#ifndef arch_atomic64_inc_overflow +#define arch_atomic64_inc_overflow(_v, _label) \ +do { \ + s64 __old = arch_atomic64_fetch_inc(_v); \ + if (unlikely(__old <= 0)) \ + goto _label; \ +} while (0) +#endif + +#ifndef arch_atomic64_dec_overflow +#define arch_atomic64_dec_overflow(_v, _label) \ +do { \ + s64 __new = arch_atomic64_dec_return(_v); \ + if (unlikely(__new <= 0)) \ + goto _label; \ +} while (0) +#endif + +#ifndef arch_atomic64_dec_and_test_overflow +#define arch_atomic64_dec_and_test_overflow(_v, _label) \ +({ \ + bool __ret = false; \ + s64 __new = arch_atomic64_dec_return(_v); \ + if (unlikely(__new < 0)) \ + goto _label; \ + if (unlikely(__new == 0)) \ + __ret = true; \ + __ret; \ +}) +#endif + #endif /* _LINUX_ATOMIC_FALLBACK_H */ -// cca554917d7ea73d5e3e7397dd70c484cad9b2c4 +// e4c677b23b3fd5e8dc4bce9d6c055103666cfc4a --- a/include/linux/atomic/atomic-instrumented.h +++ b/include/linux/atomic/atomic-instrumented.h @@ -599,6 +599,27 @@ atomic_dec_if_positive(atomic_t *v) return arch_atomic_dec_if_positive(v); } +#define atomic_inc_overflow(v, L) \ +({ \ + typeof(v) __ai_v = (v); \ + instrument_atomic_read_write(__ai_v, sizeof(*__ai_v)); \ + arch_atomic_inc_overflow(__ai_v, L); \ +}) + +#define atomic_dec_overflow(v, L) \ +({ \ + typeof(v) __ai_v = (v); \ + instrument_atomic_read_write(__ai_v, sizeof(*__ai_v)); \ + arch_atomic_dec_overflow(__ai_v, L); \ +}) + +#define atomic_dec_and_test_overflow(v, L) \ +({ \ + typeof(v) __ai_v = (v); \ + instrument_atomic_read_write(__ai_v, sizeof(*__ai_v)); \ + arch_atomic_dec_and_test_overflow(__ai_v, L); \ +}) + static __always_inline s64 atomic64_read(const atomic64_t *v) { @@ -1177,6 +1198,27 @@ atomic64_dec_if_positive(atomic64_t *v) return arch_atomic64_dec_if_positive(v); } +#define atomic64_inc_overflow(v, L) \ +({ \ + typeof(v) __ai_v = (v); \ + instrument_atomic_read_write(__ai_v, sizeof(*__ai_v)); \ + arch_atomic64_inc_overflow(__ai_v, L); \ +}) + +#define atomic64_dec_overflow(v, L) \ +({ \ + typeof(v) __ai_v = (v); \ + instrument_atomic_read_write(__ai_v, sizeof(*__ai_v)); \ + arch_atomic64_dec_overflow(__ai_v, L); \ +}) + +#define atomic64_dec_and_test_overflow(v, L) \ +({ \ + typeof(v) __ai_v = (v); \ + instrument_atomic_read_write(__ai_v, sizeof(*__ai_v)); \ + arch_atomic64_dec_and_test_overflow(__ai_v, L); \ +}) + static __always_inline long atomic_long_read(const atomic_long_t *v) { @@ -1755,6 +1797,27 @@ atomic_long_dec_if_positive(atomic_long_ return arch_atomic_long_dec_if_positive(v); } +#define atomic_long_inc_overflow(v, L) \ +({ \ + typeof(v) __ai_v = (v); \ + instrument_atomic_read_write(__ai_v, sizeof(*__ai_v)); \ + arch_atomic_long_inc_overflow(__ai_v, L); \ +}) + +#define atomic_long_dec_overflow(v, L) \ +({ \ + typeof(v) __ai_v = (v); \ + instrument_atomic_read_write(__ai_v, sizeof(*__ai_v)); \ + arch_atomic_long_dec_overflow(__ai_v, L); \ +}) + +#define atomic_long_dec_and_test_overflow(v, L) \ +({ \ + typeof(v) __ai_v = (v); \ + instrument_atomic_read_write(__ai_v, sizeof(*__ai_v)); \ + arch_atomic_long_dec_and_test_overflow(__ai_v, L); \ +}) + #define xchg(ptr, ...) \ ({ \ typeof(ptr) __ai_ptr = (ptr); \ @@ -1912,4 +1975,4 @@ atomic_long_dec_if_positive(atomic_long_ #endif /* _LINUX_ATOMIC_INSTRUMENTED_H */ -// 66cdf9a0e0a995cba29c61baf018f7ef35974ae5 +// 702806891ef1d01d76767c55088264ab6a1ef77d --- a/include/linux/atomic/atomic-long.h +++ b/include/linux/atomic/atomic-long.h @@ -515,6 +515,21 @@ arch_atomic_long_dec_if_positive(atomic_ return arch_atomic64_dec_if_positive(v); } +#define arch_atomic_long_inc_overflow(v, L) \ +({ \ + arch_atomic64_inc_overflow((v), L) \ +}) + +#define arch_atomic_long_dec_overflow(v, L) \ +({ \ + arch_atomic64_dec_overflow((v), L) \ +}) + +#define arch_atomic_long_dec_and_test_overflow(v, L) \ +({ \ + arch_atomic64_dec_and_test_overflow((v), L) \ +}) + #else /* CONFIG_64BIT */ static __always_inline long @@ -1009,6 +1024,21 @@ arch_atomic_long_dec_if_positive(atomic_ return arch_atomic_dec_if_positive(v); } +#define arch_atomic_long_inc_overflow(v, L) \ +({ \ + arch_atomic_inc_overflow((v), L) \ +}) + +#define arch_atomic_long_dec_overflow(v, L) \ +({ \ + arch_atomic_dec_overflow((v), L) \ +}) + +#define arch_atomic_long_dec_and_test_overflow(v, L) \ +({ \ + arch_atomic_dec_and_test_overflow((v), L) \ +}) + #endif /* CONFIG_64BIT */ #endif /* _LINUX_ATOMIC_LONG_H */ -// e8f0e08ff072b74d180eabe2ad001282b38c2c88 +// 487bc4fea91f23f2a4b42af7d5b49ef9172ae792 --- a/scripts/atomic/atomics.tbl +++ b/scripts/atomic/atomics.tbl @@ -44,3 +44,6 @@ inc_not_zero b v inc_unless_negative b v dec_unless_positive b v dec_if_positive i v +inc_overflow n v L +dec_overflow n v L +dec_and_test_overflow m v L --- /dev/null +++ b/scripts/atomic/fallbacks/dec_and_test_overflow @@ -0,0 +1,12 @@ +cat << EOF +#define arch_${atomic}_dec_and_test_overflow(_v, _label) \\ +({ \\ + bool __ret = false; \\ + ${int} __new = arch_${atomic}_dec_return(_v); \\ + if (unlikely(__new < 0)) \\ + goto _label; \\ + if (unlikely(__new == 0)) \\ + __ret = true; \\ + __ret; \\ +}) +EOF --- /dev/null +++ b/scripts/atomic/fallbacks/dec_overflow @@ -0,0 +1,8 @@ +cat << EOF +#define arch_${atomic}_dec_overflow(_v, _label) \\ +do { \\ + ${int} __new = arch_${atomic}_dec_return(_v); \\ + if (unlikely(__new <= 0)) \\ + goto _label; \\ +} while (0) +EOF --- /dev/null +++ b/scripts/atomic/fallbacks/inc_overflow @@ -0,0 +1,8 @@ +cat << EOF +#define arch_${atomic}_inc_overflow(_v, _label) \\ +do { \\ + ${int} __old = arch_${atomic}_fetch_inc(_v); \\ + if (unlikely(__old <= 0)) \\ + goto _label; \\ +} while (0) +EOF
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