From: "H. Peter Anvin (Intel)" <hpa@zytor.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
x86@kernel.org, "H. Peter Anvin (Intel)" <hpa@zytor.com>
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 [thread overview]
Message-ID: <20210909220818.417312-2-hpa@zytor.com> (raw)
In-Reply-To: <20210909220818.417312-1-hpa@zytor.com>
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
next prev parent reply other threads:[~2021-09-09 22:08 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-08 17:17 [PATCH] x86/asm: pessimize the pre-initialization case in static_cpu_has() H. Peter Anvin (Intel)
2021-09-09 17:01 ` Borislav Petkov
2021-09-09 21:28 ` H. Peter Anvin
2021-09-09 21:53 ` Borislav Petkov
2021-09-09 22:17 ` H. Peter Anvin
2021-09-10 9:14 ` Borislav Petkov
2021-09-10 19:25 ` H. Peter Anvin
2021-09-09 22:08 ` [PATCH v2 0/2] x86/asm: avoid register pressure from static_cpu_has() H. Peter Anvin (Intel)
2021-09-09 22:08 ` H. Peter Anvin (Intel) [this message]
2021-09-09 22:08 ` [PATCH v2 2/2] x86/asm: pessimize the pre-initialization case in static_cpu_has() H. Peter Anvin (Intel)
2021-09-10 9:16 ` [PATCH v2 0/2] x86/asm: avoid register pressure from static_cpu_has() Borislav Petkov
2021-09-10 13:24 ` Borislav Petkov
2021-09-10 19:59 ` [PATCH v3 0/2] x86/asm: avoid register pressure from the init case in static_cpu_has() H. Peter Anvin (Intel)
2021-09-10 19:59 ` [PATCH] drm/bochs: add Bochs PCI ID for Simics model H. Peter Anvin (Intel)
2021-09-10 19:59 ` [PATCH v3 1/2] x86/asm: add _ASM_RIP() macro for x86-64 (%rip) suffix H. Peter Anvin (Intel)
2021-09-13 19:39 ` [tip: x86/cpu] x86/asm: Add " tip-bot2 for H. Peter Anvin (Intel)
2021-09-10 19:59 ` [PATCH v3 2/2] x86/asm: avoid adding register pressure for the init case in static_cpu_has() H. Peter Anvin (Intel)
2021-09-13 19:39 ` [tip: x86/cpu] x86/asm: Avoid " tip-bot2 for H. Peter Anvin
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