Messages in this thread Patch in this message | | | From | "H. Peter Anvin (Intel)" <> | Subject | [PATCH v2 1/2] x86/asm: add _ASM_RIP() macro for x86-64 (%rip) suffix | Date | Thu, 9 Sep 2021 15:08:17 -0700 |
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Add a macro _ASM_RIP() to add a (%rip) suffix on 64 bits only. This is useful for immediate memory references using e.g. an "i" constraint where one doesn't want gcc to possibly use a register indirection as it may in the case of an "m" constraint.
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com> --- arch/x86/include/asm/asm.h | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h index 3ad3da9a7d97..c5a19ccda0fe 100644 --- a/arch/x86/include/asm/asm.h +++ b/arch/x86/include/asm/asm.h @@ -6,11 +6,13 @@ # define __ASM_FORM(x, ...) x,## __VA_ARGS__ # define __ASM_FORM_RAW(x, ...) x,## __VA_ARGS__ # define __ASM_FORM_COMMA(x, ...) x,## __VA_ARGS__, +# define __ASM_REGPFX % #else #include <linux/stringify.h> # define __ASM_FORM(x, ...) " " __stringify(x,##__VA_ARGS__) " " # define __ASM_FORM_RAW(x, ...) __stringify(x,##__VA_ARGS__) # define __ASM_FORM_COMMA(x, ...) " " __stringify(x,##__VA_ARGS__) "," +# define __ASM_REGPFX %% #endif #define _ASM_BYTES(x, ...) __ASM_FORM(.byte x,##__VA_ARGS__ ;) @@ -49,6 +51,9 @@ #define _ASM_SI __ASM_REG(si) #define _ASM_DI __ASM_REG(di) +/* Adds a (%rip) suffix on 64 bits only; for immediate memory references */ +#define _ASM_RIP(x) __ASM_SEL_RAW(x, x (__ASM_REGPFX rip)) + #ifndef __x86_64__ /* 32 bit */ -- 2.31.1
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