diff options
author | Peter Zijlstra <peterz@infradead.org> | 2022-10-21 14:36:24 +0300 |
---|---|---|
committer | Dave Hansen <dave.hansen@linux.intel.com> | 2022-12-15 21:37:27 +0300 |
commit | d4a72e7fe61a1ea9ad4accf3532411ca685eaead (patch) | |
tree | 58dbd4e342f31cbb412fabf323533208dafbab2f /arch/x86/include/asm/cmpxchg_32.h | |
parent | 9ee850acd25dc290d3cad2707e99380e372ad490 (diff) | |
download | linux-d4a72e7fe61a1ea9ad4accf3532411ca685eaead.tar.xz |
x86/mm/pae: Get rid of set_64bit()
Recognise that set_64bit() is a special case of our previously
introduced pxx_xchg64(), so use that and get rid of set_64bit().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221022114425.233481884%40infradead.org
Diffstat (limited to 'arch/x86/include/asm/cmpxchg_32.h')
-rw-r--r-- | arch/x86/include/asm/cmpxchg_32.h | 28 |
1 files changed, 0 insertions, 28 deletions
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h index 215f5a65790f..6ba80ce9438d 100644 --- a/arch/x86/include/asm/cmpxchg_32.h +++ b/arch/x86/include/asm/cmpxchg_32.h @@ -7,34 +7,6 @@ * you need to test for the feature in boot_cpu_data. */ -/* - * CMPXCHG8B only writes to the target if we had the previous - * value in registers, otherwise it acts as a read and gives us the - * "new previous" value. That is why there is a loop. Preloading - * EDX:EAX is a performance optimization: in the common case it means - * we need only one locked operation. - * - * A SIMD/3DNOW!/MMX/FPU 64-bit store here would require at the very - * least an FPU save and/or %cr0.ts manipulation. - * - * cmpxchg8b must be used with the lock prefix here to allow the - * instruction to be executed atomically. We need to have the reader - * side to see the coherent 64bit value. - */ -static inline void set_64bit(volatile u64 *ptr, u64 value) -{ - u32 low = value; - u32 high = value >> 32; - u64 prev = *ptr; - - asm volatile("\n1:\t" - LOCK_PREFIX "cmpxchg8b %0\n\t" - "jnz 1b" - : "=m" (*ptr), "+A" (prev) - : "b" (low), "c" (high) - : "memory"); -} - #ifdef CONFIG_X86_CMPXCHG64 #define arch_cmpxchg64(ptr, o, n) \ ((__typeof__(*(ptr)))__cmpxchg64((ptr), (unsigned long long)(o), \ |