diff options
| author | Sean Christopherson <seanjc@google.com> | 2022-11-19 01:34:50 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-12-02 13:22:35 -0500 |
| commit | bb056c0f080a3d15c2a9ad9057a8b542d45e4ba0 (patch) | |
| tree | a7231d2f04e11798c35e848bcfbddb4db0bc098b /tools/include | |
| parent | 36293352ff433061d45d52784983e44950c09ae3 (diff) | |
| download | linux-bb056c0f080a3d15c2a9ad9057a8b542d45e4ba0.tar.bz2 | |
tools: KVM: selftests: Convert clear/set_bit() to actual atomics
Convert {clear,set}_bit() to atomics as KVM's ucall implementation relies
on clear_bit() being atomic, they are defined in atomic.h, and the same
helpers in the kernel proper are atomic.
KVM's ucall infrastructure is the only user of clear_bit() in tools/, and
there are no true set_bit() users. tools/testing/nvdimm/ does make heavy
use of set_bit(), but that code builds into a kernel module of sorts, i.e.
pulls in all of the kernel's header and so is already getting the kernel's
atomic set_bit().
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221119013450.2643007-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'tools/include')
| -rw-r--r-- | tools/include/asm-generic/atomic-gcc.h | 11 | ||||
| -rw-r--r-- | tools/include/asm-generic/bitops/atomic.h | 15 |
2 files changed, 17 insertions, 9 deletions
diff --git a/tools/include/asm-generic/atomic-gcc.h b/tools/include/asm-generic/atomic-gcc.h index 37ef522aaac4..9b3c528bab92 100644 --- a/tools/include/asm-generic/atomic-gcc.h +++ b/tools/include/asm-generic/atomic-gcc.h @@ -81,4 +81,15 @@ static inline int test_and_set_bit(long nr, unsigned long *addr) return !!(old & mask); } +static inline int test_and_clear_bit(long nr, unsigned long *addr) +{ + unsigned long mask = BIT_MASK(nr); + long old; + + addr += BIT_WORD(nr); + + old = __sync_fetch_and_and(addr, ~mask); + return !!(old & mask); +} + #endif /* __TOOLS_ASM_GENERIC_ATOMIC_H */ diff --git a/tools/include/asm-generic/bitops/atomic.h b/tools/include/asm-generic/bitops/atomic.h index f64b049d236c..ab37a221b41a 100644 --- a/tools/include/asm-generic/bitops/atomic.h +++ b/tools/include/asm-generic/bitops/atomic.h @@ -5,14 +5,11 @@ #include <asm/types.h> #include <asm/bitsperlong.h> -static inline void set_bit(unsigned long nr, unsigned long *addr) -{ - addr[nr / __BITS_PER_LONG] |= 1UL << (nr % __BITS_PER_LONG); -} - -static inline void clear_bit(unsigned long nr, unsigned long *addr) -{ - addr[nr / __BITS_PER_LONG] &= ~(1UL << (nr % __BITS_PER_LONG)); -} +/* + * Just alias the test versions, all of the compiler built-in atomics "fetch", + * and optimizing compile-time constants on x86 isn't worth the complexity. + */ +#define set_bit test_and_set_bit +#define clear_bit test_and_clear_bit #endif /* _TOOLS_LINUX_ASM_GENERIC_BITOPS_ATOMIC_H_ */ |