From cf3ee3c8c29dc349b2cf52e5e72e8cb805ff5e57 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 13 Jul 2021 11:52:53 +0100 Subject: [PATCH] locking/atomic: add generic arch_*() bitops Now that all architectures provide arch_atomic_long_*(), we can implement the generic bitops atop these rather than atop atomic_long_*(), and provide arch_*() forms of the bitops that are safe to use in noinstr code. Now that all architectures provide arch_atomic_long_*(), we can build the generic arch_*() bitops atop these, which can be safely used in noinstr code. The regular bitop wrappers are built atop these. As the generic non-atomic bitops use plain accesses, these will be implicitly instrumented unless they are inlined into noinstr functions (which is similar to arch_atomic*_read() when based on READ_ONCE()). The wrappers are modified so that where the underlying arch_*() function uses a plain access, no explicit instrumentation is added, as this is redundant and could result in confusing reports. Since function prototypes get excessively long with both an `arch_` prefix and `__always_inline` attribute, the return type and function attributes have been split onto a separate line, matching the style of the generated atomic headers. Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210713105253.7615-6-mark.rutland@arm.com --- include/asm-generic/bitops/atomic.h | 32 +++++++++------ .../bitops/instrumented-non-atomic.h | 21 ++++++---- include/asm-generic/bitops/lock.h | 39 ++++++++++-------- include/asm-generic/bitops/non-atomic.h | 41 +++++++++++++------ 4 files changed, 83 insertions(+), 50 deletions(-) diff --git a/include/asm-generic/bitops/atomic.h b/include/asm-generic/bitops/atomic.h index 0e7316a86240..3096f086b5a3 100644 --- a/include/asm-generic/bitops/atomic.h +++ b/include/asm-generic/bitops/atomic.h @@ -11,25 +11,29 @@ * See Documentation/atomic_bitops.txt for details. */ -static __always_inline void set_bit(unsigned int nr, volatile unsigned long *p) +static __always_inline void +arch_set_bit(unsigned int nr, volatile unsigned long *p) { p += BIT_WORD(nr); - atomic_long_or(BIT_MASK(nr), (atomic_long_t *)p); + arch_atomic_long_or(BIT_MASK(nr), (atomic_long_t *)p); } -static __always_inline void clear_bit(unsigned int nr, volatile unsigned long *p) +static __always_inline void +arch_clear_bit(unsigned int nr, volatile unsigned long *p) { p += BIT_WORD(nr); - atomic_long_andnot(BIT_MASK(nr), (atomic_long_t *)p); + arch_atomic_long_andnot(BIT_MASK(nr), (atomic_long_t *)p); } -static __always_inline void change_bit(unsigned int nr, volatile unsigned long *p) +static __always_inline void +arch_change_bit(unsigned int nr, volatile unsigned long *p) { p += BIT_WORD(nr); - atomic_long_xor(BIT_MASK(nr), (atomic_long_t *)p); + arch_atomic_long_xor(BIT_MASK(nr), (atomic_long_t *)p); } -static inline int test_and_set_bit(unsigned int nr, volatile unsigned long *p) +static __always_inline int +arch_test_and_set_bit(unsigned int nr, volatile unsigned long *p) { long old; unsigned long mask = BIT_MASK(nr); @@ -38,11 +42,12 @@ static inline int test_and_set_bit(unsigned int nr, volatile unsigned long *p) if (READ_ONCE(*p) & mask) return 1; - old = atomic_long_fetch_or(mask, (atomic_long_t *)p); + old = arch_atomic_long_fetch_or(mask, (atomic_long_t *)p); return !!(old & mask); } -static inline int test_and_clear_bit(unsigned int nr, volatile unsigned long *p) +static __always_inline int +arch_test_and_clear_bit(unsigned int nr, volatile unsigned long *p) { long old; unsigned long mask = BIT_MASK(nr); @@ -51,18 +56,21 @@ static inline int test_and_clear_bit(unsigned int nr, volatile unsigned long *p) if (!(READ_ONCE(*p) & mask)) return 0; - old = atomic_long_fetch_andnot(mask, (atomic_long_t *)p); + old = arch_atomic_long_fetch_andnot(mask, (atomic_long_t *)p); return !!(old & mask); } -static inline int test_and_change_bit(unsigned int nr, volatile unsigned long *p) +static __always_inline int +arch_test_and_change_bit(unsigned int nr, volatile unsigned long *p) { long old; unsigned long mask = BIT_MASK(nr); p += BIT_WORD(nr); - old = atomic_long_fetch_xor(mask, (atomic_long_t *)p); + old = arch_atomic_long_fetch_xor(mask, (atomic_long_t *)p); return !!(old & mask); } +#include + #endif /* _ASM_GENERIC_BITOPS_ATOMIC_H */ diff --git a/include/asm-generic/bitops/instrumented-non-atomic.h b/include/asm-generic/bitops/instrumented-non-atomic.h index 37363d570b9b..e6c1540965d6 100644 --- a/include/asm-generic/bitops/instrumented-non-atomic.h +++ b/include/asm-generic/bitops/instrumented-non-atomic.h @@ -24,7 +24,8 @@ */ static inline void __set_bit(long nr, volatile unsigned long *addr) { - instrument_write(addr + BIT_WORD(nr), sizeof(long)); + if (!__is_defined(arch___set_bit_uses_plain_access)) + instrument_write(addr + BIT_WORD(nr), sizeof(long)); arch___set_bit(nr, addr); } @@ -39,7 +40,8 @@ static inline void __set_bit(long nr, volatile unsigned long *addr) */ static inline void __clear_bit(long nr, volatile unsigned long *addr) { - instrument_write(addr + BIT_WORD(nr), sizeof(long)); + if (!__is_defined(arch___clear_bit_uses_plain_access)) + instrument_write(addr + BIT_WORD(nr), sizeof(long)); arch___clear_bit(nr, addr); } @@ -54,7 +56,8 @@ static inline void __clear_bit(long nr, volatile unsigned long *addr) */ static inline void __change_bit(long nr, volatile unsigned long *addr) { - instrument_write(addr + BIT_WORD(nr), sizeof(long)); + if (!__is_defined(arch___change_bit_uses_plain_access)) + instrument_write(addr + BIT_WORD(nr), sizeof(long)); arch___change_bit(nr, addr); } @@ -92,7 +95,8 @@ static inline void __instrument_read_write_bitop(long nr, volatile unsigned long */ static inline bool __test_and_set_bit(long nr, volatile unsigned long *addr) { - __instrument_read_write_bitop(nr, addr); + if (!__is_defined(arch___test_and_set_bit_uses_plain_access)) + __instrument_read_write_bitop(nr, addr); return arch___test_and_set_bit(nr, addr); } @@ -106,7 +110,8 @@ static inline bool __test_and_set_bit(long nr, volatile unsigned long *addr) */ static inline bool __test_and_clear_bit(long nr, volatile unsigned long *addr) { - __instrument_read_write_bitop(nr, addr); + if (!__is_defined(arch___test_and_clear_bit_uses_plain_access)) + __instrument_read_write_bitop(nr, addr); return arch___test_and_clear_bit(nr, addr); } @@ -120,7 +125,8 @@ static inline bool __test_and_clear_bit(long nr, volatile unsigned long *addr) */ static inline bool __test_and_change_bit(long nr, volatile unsigned long *addr) { - __instrument_read_write_bitop(nr, addr); + if (!__is_defined(arch___test_and_change_bit_uses_plain_access)) + __instrument_read_write_bitop(nr, addr); return arch___test_and_change_bit(nr, addr); } @@ -131,7 +137,8 @@ static inline bool __test_and_change_bit(long nr, volatile unsigned long *addr) */ static inline bool test_bit(long nr, const volatile unsigned long *addr) { - instrument_atomic_read(addr + BIT_WORD(nr), sizeof(long)); + if (!__is_defined(arch_test_bit_uses_plain_access)) + instrument_atomic_read(addr + BIT_WORD(nr), sizeof(long)); return arch_test_bit(nr, addr); } diff --git a/include/asm-generic/bitops/lock.h b/include/asm-generic/bitops/lock.h index 3ae021368f48..630f2f6b9595 100644 --- a/include/asm-generic/bitops/lock.h +++ b/include/asm-generic/bitops/lock.h @@ -7,7 +7,7 @@ #include /** - * test_and_set_bit_lock - Set a bit and return its old value, for lock + * arch_test_and_set_bit_lock - Set a bit and return its old value, for lock * @nr: Bit to set * @addr: Address to count from * @@ -15,8 +15,8 @@ * the returned value is 0. * It can be used to implement bit locks. */ -static inline int test_and_set_bit_lock(unsigned int nr, - volatile unsigned long *p) +static __always_inline int +arch_test_and_set_bit_lock(unsigned int nr, volatile unsigned long *p) { long old; unsigned long mask = BIT_MASK(nr); @@ -25,26 +25,27 @@ static inline int test_and_set_bit_lock(unsigned int nr, if (READ_ONCE(*p) & mask) return 1; - old = atomic_long_fetch_or_acquire(mask, (atomic_long_t *)p); + old = arch_atomic_long_fetch_or_acquire(mask, (atomic_long_t *)p); return !!(old & mask); } /** - * clear_bit_unlock - Clear a bit in memory, for unlock + * arch_clear_bit_unlock - Clear a bit in memory, for unlock * @nr: the bit to set * @addr: the address to start counting from * * This operation is atomic and provides release barrier semantics. */ -static inline void clear_bit_unlock(unsigned int nr, volatile unsigned long *p) +static __always_inline void +arch_clear_bit_unlock(unsigned int nr, volatile unsigned long *p) { p += BIT_WORD(nr); - atomic_long_fetch_andnot_release(BIT_MASK(nr), (atomic_long_t *)p); + arch_atomic_long_fetch_andnot_release(BIT_MASK(nr), (atomic_long_t *)p); } /** - * __clear_bit_unlock - Clear a bit in memory, for unlock + * arch___clear_bit_unlock - Clear a bit in memory, for unlock * @nr: the bit to set * @addr: the address to start counting from * @@ -54,38 +55,40 @@ static inline void clear_bit_unlock(unsigned int nr, volatile unsigned long *p) * * See for example x86's implementation. */ -static inline void __clear_bit_unlock(unsigned int nr, - volatile unsigned long *p) +static inline void +arch___clear_bit_unlock(unsigned int nr, volatile unsigned long *p) { unsigned long old; p += BIT_WORD(nr); old = READ_ONCE(*p); old &= ~BIT_MASK(nr); - atomic_long_set_release((atomic_long_t *)p, old); + arch_atomic_long_set_release((atomic_long_t *)p, old); } /** - * clear_bit_unlock_is_negative_byte - Clear a bit in memory and test if bottom - * byte is negative, for unlock. + * arch_clear_bit_unlock_is_negative_byte - Clear a bit in memory and test if bottom + * byte is negative, for unlock. * @nr: the bit to clear * @addr: the address to start counting from * * This is a bit of a one-trick-pony for the filemap code, which clears * PG_locked and tests PG_waiters, */ -#ifndef clear_bit_unlock_is_negative_byte -static inline bool clear_bit_unlock_is_negative_byte(unsigned int nr, - volatile unsigned long *p) +#ifndef arch_clear_bit_unlock_is_negative_byte +static inline bool arch_clear_bit_unlock_is_negative_byte(unsigned int nr, + volatile unsigned long *p) { long old; unsigned long mask = BIT_MASK(nr); p += BIT_WORD(nr); - old = atomic_long_fetch_andnot_release(mask, (atomic_long_t *)p); + old = arch_atomic_long_fetch_andnot_release(mask, (atomic_long_t *)p); return !!(old & BIT(7)); } -#define clear_bit_unlock_is_negative_byte clear_bit_unlock_is_negative_byte +#define arch_clear_bit_unlock_is_negative_byte arch_clear_bit_unlock_is_negative_byte #endif +#include + #endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */ diff --git a/include/asm-generic/bitops/non-atomic.h b/include/asm-generic/bitops/non-atomic.h index 7e10c4b50c5d..c8149cd52730 100644 --- a/include/asm-generic/bitops/non-atomic.h +++ b/include/asm-generic/bitops/non-atomic.h @@ -5,7 +5,7 @@ #include /** - * __set_bit - Set a bit in memory + * arch___set_bit - Set a bit in memory * @nr: the bit to set * @addr: the address to start counting from * @@ -13,24 +13,28 @@ * If it's called on the same region of memory simultaneously, the effect * may be that only one operation succeeds. */ -static inline void __set_bit(int nr, volatile unsigned long *addr) +static __always_inline void +arch___set_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); *p |= mask; } +#define arch___set_bit_uses_plain_access -static inline void __clear_bit(int nr, volatile unsigned long *addr) +static __always_inline void +arch___clear_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); *p &= ~mask; } +#define arch___clear_bit_uses_plain_access /** - * __change_bit - Toggle a bit in memory + * arch___change_bit - Toggle a bit in memory * @nr: the bit to change * @addr: the address to start counting from * @@ -38,16 +42,18 @@ static inline void __clear_bit(int nr, volatile unsigned long *addr) * If it's called on the same region of memory simultaneously, the effect * may be that only one operation succeeds. */ -static inline void __change_bit(int nr, volatile unsigned long *addr) +static __always_inline +void arch___change_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); *p ^= mask; } +#define arch___change_bit_uses_plain_access /** - * __test_and_set_bit - Set a bit and return its old value + * arch___test_and_set_bit - Set a bit and return its old value * @nr: Bit to set * @addr: Address to count from * @@ -55,7 +61,8 @@ static inline void __change_bit(int nr, volatile unsigned long *addr) * If two examples of this operation race, one can appear to succeed * but actually fail. You must protect multiple accesses with a lock. */ -static inline int __test_and_set_bit(int nr, volatile unsigned long *addr) +static __always_inline int +arch___test_and_set_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); @@ -64,9 +71,10 @@ static inline int __test_and_set_bit(int nr, volatile unsigned long *addr) *p = old | mask; return (old & mask) != 0; } +#define arch___test_and_set_bit_uses_plain_access /** - * __test_and_clear_bit - Clear a bit and return its old value + * arch___test_and_clear_bit - Clear a bit and return its old value * @nr: Bit to clear * @addr: Address to count from * @@ -74,7 +82,8 @@ static inline int __test_and_set_bit(int nr, volatile unsigned long *addr) * If two examples of this operation race, one can appear to succeed * but actually fail. You must protect multiple accesses with a lock. */ -static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr) +static __always_inline int +arch___test_and_clear_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); @@ -83,10 +92,11 @@ static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr) *p = old & ~mask; return (old & mask) != 0; } +#define arch___test_and_clear_bit_uses_plain_access /* WARNING: non atomic and it can be reordered! */ -static inline int __test_and_change_bit(int nr, - volatile unsigned long *addr) +static __always_inline int +arch___test_and_change_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); @@ -95,15 +105,20 @@ static inline int __test_and_change_bit(int nr, *p = old ^ mask; return (old & mask) != 0; } +#define arch___test_and_change_bit_uses_plain_access /** - * test_bit - Determine whether a bit is set + * arch_test_bit - Determine whether a bit is set * @nr: bit number to test * @addr: Address to start counting from */ -static inline int test_bit(int nr, const volatile unsigned long *addr) +static __always_inline int +arch_test_bit(int nr, const volatile unsigned long *addr) { return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1))); } +#define arch_test_bit_uses_plain_access + +#include #endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */