From: "H. Peter Anvin (Intel)" hpa@zytor.com
commit f87bc8dc7a7c438c70f97b4e51c76a183313272e upstream.
Add a macro _ASM_RIP() to add a (%rip) suffix on 64 bits only. This is useful for immediate memory references 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 Signed-off-by: Borislav Petkov bp@suse.de Signed-off-by: Pawan Gupta pawan.kumar.gupta@linux.intel.com Link: https://lkml.kernel.org/r/20210910195910.2542662-3-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 0603c7423aca..c01005d7a4ed 100644 --- a/arch/x86/include/asm/asm.h +++ b/arch/x86/include/asm/asm.h @@ -6,12 +6,14 @@ # define __ASM_FORM(x) x # define __ASM_FORM_RAW(x) x # define __ASM_FORM_COMMA(x) x, +# define __ASM_REGPFX % #else #include <linux/stringify.h>
# define __ASM_FORM(x) " " __stringify(x) " " # define __ASM_FORM_RAW(x) __stringify(x) # define __ASM_FORM_COMMA(x) " " __stringify(x) "," +# define __ASM_REGPFX %% #endif
#ifndef __x86_64__ @@ -48,6 +50,9 @@ #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 */