linux-kernel - Re: [PATCH] x86/boot: Use __ASM_SIZE() to reduce ifdeffery in cpuflags.c

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Message-ID: <4049EB19-E869-4886-AD61-E716A75E4559@zytor.com>
Date: Wed, 17 Jul 2024 23:35:57 -0700
From: "H. Peter Anvin" <hpa@...or.com>
To: Uros Bizjak <ubizjak@...il.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
CC: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...nel.org>,
        Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>
Subject: Re: [PATCH] x86/boot: Use __ASM_SIZE() to reduce ifdeffery in cpuflags.c

On July 17, 2024 11:32:18 PM PDT, Uros Bizjak <ubizjak@...il.com> wrote:
>Use __ASM_SIZE() macro to add correct insn suffix to pushf/popf.
>
>Signed-off-by: Uros Bizjak <ubizjak@...il.com>
>Cc: Thomas Gleixner <tglx@...utronix.de>
>Cc: Ingo Molnar <mingo@...nel.org>
>Cc: Borislav Petkov <bp@...en8.de>
>Cc: Dave Hansen <dave.hansen@...ux.intel.com>
>Cc: "H. Peter Anvin" <hpa@...or.com>
>---
> arch/x86/boot/cpuflags.c | 10 +++-------
> 1 file changed, 3 insertions(+), 7 deletions(-)
>
>diff --git a/arch/x86/boot/cpuflags.c b/arch/x86/boot/cpuflags.c
>index d75237ba7ce9..aacabe431fd5 100644
>--- a/arch/x86/boot/cpuflags.c
>+++ b/arch/x86/boot/cpuflags.c
>@@ -2,6 +2,7 @@
> #include <linux/types.h>
> #include "bitops.h"
> 
>+#include <asm/asm.h>
> #include <asm/processor-flags.h>
> #include <asm/required-features.h>
> #include <asm/msr-index.h>
>@@ -36,13 +37,8 @@ static int has_fpu(void)
>  * compressed/ directory where it may be 64-bit code, and thus needs
>  * to be 'pushfq' or 'popfq' in that case.
>  */
>-#ifdef __x86_64__
>-#define PUSHF "pushfq"
>-#define POPF "popfq"
>-#else
>-#define PUSHF "pushfl"
>-#define POPF "popfl"
>-#endif
>+#define PUSHF __ASM_SIZE(pushf)
>+#define POPF __ASM_SIZE(popf)
> 
> int has_eflag(unsigned long mask)
> {

Just use pushf/popf. gas hasn't needed that suffix for a long time as far as I know.