From a930dc4543a2b213deb9fde12682716edff8a4a6 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Sun, 18 Jan 2015 17:48:18 +0100 Subject: x86/asm: Cleanup prefetch primitives This is based on a patch originally by hpa. With the current improvements to the alternatives, we can simply use %P1 as a mem8 operand constraint and rely on the toolchain to generate the proper instruction sizes. For example, on 32-bit, where we use an empty old instruction we get: apply_alternatives: feat: 6*32+8, old: (c104648b, len: 4), repl: (c195566c, len: 4) c104648b: alt_insn: 90 90 90 90 c195566c: rpl_insn: 0f 0d 4b 5c ... apply_alternatives: feat: 6*32+8, old: (c18e09b4, len: 3), repl: (c1955948, len: 3) c18e09b4: alt_insn: 90 90 90 c1955948: rpl_insn: 0f 0d 08 ... apply_alternatives: feat: 6*32+8, old: (c1190cf9, len: 7), repl: (c1955a79, len: 7) c1190cf9: alt_insn: 90 90 90 90 90 90 90 c1955a79: rpl_insn: 0f 0d 0d a0 d4 85 c1 all with the proper padding done depending on the size of the replacement instruction the compiler generates. Signed-off-by: Borislav Petkov Cc: H. Peter Anvin --- arch/x86/include/asm/processor.h | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'arch/x86/include/asm/processor.h') diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index ec1c93588cef..7be2c9a6caba 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -761,10 +761,10 @@ extern char ignore_fpu_irq; #define ARCH_HAS_SPINLOCK_PREFETCH #ifdef CONFIG_X86_32 -# define BASE_PREFETCH ASM_NOP4 +# define BASE_PREFETCH "" # define ARCH_HAS_PREFETCH #else -# define BASE_PREFETCH "prefetcht0 (%1)" +# define BASE_PREFETCH "prefetcht0 %P1" #endif /* @@ -775,10 +775,9 @@ extern char ignore_fpu_irq; */ static inline void prefetch(const void *x) { - alternative_input(BASE_PREFETCH, - "prefetchnta (%1)", + alternative_input(BASE_PREFETCH, "prefetchnta %P1", X86_FEATURE_XMM, - "r" (x)); + "m" (*(const char *)x)); } /* @@ -788,10 +787,9 @@ static inline void prefetch(const void *x) */ static inline void prefetchw(const void *x) { - alternative_input(BASE_PREFETCH, - "prefetchw (%1)", - X86_FEATURE_3DNOW, - "r" (x)); + alternative_input(BASE_PREFETCH, "prefetchw %P1", + X86_FEATURE_3DNOWPREFETCH, + "m" (*(const char *)x)); } static inline void spin_lock_prefetch(const void *x) -- cgit v1.2.3