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authorMark Rutland <mark.rutland@arm.com>2018-07-16 12:30:08 +0100
committerIngo Molnar <mingo@kernel.org>2018-07-25 11:53:58 +0200
commitdf79ed2c064363cdc7d2d896923c1885d4e30520 (patch)
tree92fcd013df1fde14df209747788ed9b1ba073610 /include/asm-generic
parent00d5551cc4eec0fc39c3871c25c613553acfb866 (diff)
downloadblackbird-obmc-linux-df79ed2c064363cdc7d2d896923c1885d4e30520.tar.gz
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locking/atomics: Simplify cmpxchg() instrumentation
Currently we define some fairly verbose wrappers for the cmpxchg() family so that we can pass a pointer and size into kasan_check_write(). The wrappers duplicate the size-switching logic necessary in arch code, and only work for scalar types. On some architectures, (cmp)xchg are used on non-scalar types, and thus the instrumented wrappers need to be able to handle this. We could take the type-punning logic from {READ,WRITE}_ONCE(), but this makes the wrappers even more verbose, and requires several local variables in the macros. Instead, let's simplify the wrappers into simple macros which: * snapshot the pointer into a single local variable, called __ai_ptr to avoid conflicts with variables in the scope of the caller. * call kasan_check_write() on __ai_ptr. * invoke the relevant arch_*() function, passing the original arguments, bar __ai_ptr being substituted for ptr. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: andy.shevchenko@gmail.com Cc: arnd@arndb.de Cc: aryabinin@virtuozzo.com Cc: catalin.marinas@arm.com Cc: glider@google.com Cc: linux-arm-kernel@lists.infradead.org Cc: parri.andrea@gmail.com Cc: peter@hurleysoftware.com Link: http://lkml.kernel.org/r/20180716113017.3909-4-mark.rutland@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/atomic-instrumented.h100
1 files changed, 15 insertions, 85 deletions
diff --git a/include/asm-generic/atomic-instrumented.h b/include/asm-generic/atomic-instrumented.h
index 3c64e95d5ed0..c7c3e4cdd942 100644
--- a/include/asm-generic/atomic-instrumented.h
+++ b/include/asm-generic/atomic-instrumented.h
@@ -408,109 +408,39 @@ static __always_inline bool atomic64_add_negative(s64 i, atomic64_t *v)
}
#endif
-static __always_inline unsigned long
-cmpxchg_size(volatile void *ptr, unsigned long old, unsigned long new, int size)
-{
- kasan_check_write(ptr, size);
- switch (size) {
- case 1:
- return arch_cmpxchg((u8 *)ptr, (u8)old, (u8)new);
- case 2:
- return arch_cmpxchg((u16 *)ptr, (u16)old, (u16)new);
- case 4:
- return arch_cmpxchg((u32 *)ptr, (u32)old, (u32)new);
- case 8:
- BUILD_BUG_ON(sizeof(unsigned long) != 8);
- return arch_cmpxchg((u64 *)ptr, (u64)old, (u64)new);
- }
- BUILD_BUG();
- return 0;
-}
-
#define cmpxchg(ptr, old, new) \
({ \
- ((__typeof__(*(ptr)))cmpxchg_size((ptr), (unsigned long)(old), \
- (unsigned long)(new), sizeof(*(ptr)))); \
+ typeof(ptr) __ai_ptr = (ptr); \
+ kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \
+ arch_cmpxchg(__ai_ptr, (old), (new)); \
})
-static __always_inline unsigned long
-sync_cmpxchg_size(volatile void *ptr, unsigned long old, unsigned long new,
- int size)
-{
- kasan_check_write(ptr, size);
- switch (size) {
- case 1:
- return arch_sync_cmpxchg((u8 *)ptr, (u8)old, (u8)new);
- case 2:
- return arch_sync_cmpxchg((u16 *)ptr, (u16)old, (u16)new);
- case 4:
- return arch_sync_cmpxchg((u32 *)ptr, (u32)old, (u32)new);
- case 8:
- BUILD_BUG_ON(sizeof(unsigned long) != 8);
- return arch_sync_cmpxchg((u64 *)ptr, (u64)old, (u64)new);
- }
- BUILD_BUG();
- return 0;
-}
-
#define sync_cmpxchg(ptr, old, new) \
({ \
- ((__typeof__(*(ptr)))sync_cmpxchg_size((ptr), \
- (unsigned long)(old), (unsigned long)(new), \
- sizeof(*(ptr)))); \
+ typeof(ptr) __ai_ptr = (ptr); \
+ kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \
+ arch_sync_cmpxchg(__ai_ptr, (old), (new)); \
})
-static __always_inline unsigned long
-cmpxchg_local_size(volatile void *ptr, unsigned long old, unsigned long new,
- int size)
-{
- kasan_check_write(ptr, size);
- switch (size) {
- case 1:
- return arch_cmpxchg_local((u8 *)ptr, (u8)old, (u8)new);
- case 2:
- return arch_cmpxchg_local((u16 *)ptr, (u16)old, (u16)new);
- case 4:
- return arch_cmpxchg_local((u32 *)ptr, (u32)old, (u32)new);
- case 8:
- BUILD_BUG_ON(sizeof(unsigned long) != 8);
- return arch_cmpxchg_local((u64 *)ptr, (u64)old, (u64)new);
- }
- BUILD_BUG();
- return 0;
-}
-
#define cmpxchg_local(ptr, old, new) \
({ \
- ((__typeof__(*(ptr)))cmpxchg_local_size((ptr), \
- (unsigned long)(old), (unsigned long)(new), \
- sizeof(*(ptr)))); \
+ typeof(ptr) __ai_ptr = (ptr); \
+ kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \
+ arch_cmpxchg_local(__ai_ptr, (old), (new)); \
})
-static __always_inline u64
-cmpxchg64_size(volatile u64 *ptr, u64 old, u64 new)
-{
- kasan_check_write(ptr, sizeof(*ptr));
- return arch_cmpxchg64(ptr, old, new);
-}
-
#define cmpxchg64(ptr, old, new) \
({ \
- ((__typeof__(*(ptr)))cmpxchg64_size((ptr), (u64)(old), \
- (u64)(new))); \
+ typeof(ptr) __ai_ptr = (ptr); \
+ kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \
+ arch_cmpxchg64(__ai_ptr, (old), (new)); \
})
-static __always_inline u64
-cmpxchg64_local_size(volatile u64 *ptr, u64 old, u64 new)
-{
- kasan_check_write(ptr, sizeof(*ptr));
- return arch_cmpxchg64_local(ptr, old, new);
-}
-
#define cmpxchg64_local(ptr, old, new) \
({ \
- ((__typeof__(*(ptr)))cmpxchg64_local_size((ptr), (u64)(old), \
- (u64)(new))); \
+ typeof(ptr) __ai_ptr = (ptr); \
+ kasan_check_write(__ai_ptr, sizeof(*__ai_ptr)); \
+ arch_cmpxchg64_local(__ai_ptr, (old), (new)); \
})
/*
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