* [PATCH] x86_64: clobber flags in clear_page()
@ 2018-01-13 18:50 Alexey Dobriyan
2018-02-10 21:19 ` Borislav Petkov
2018-02-13 16:59 ` [tip:x86/asm] x86/asm: Clobber " tip-bot for Alexey Dobriyan
0 siblings, 2 replies; 3+ messages in thread
From: Alexey Dobriyan @ 2018-01-13 18:50 UTC (permalink / raw)
To: tglx, mingo, hpa; +Cc: x86, linux-kernel, bp
All clear_page() implementations use XOR which resets flags.
Judging by allyesconfig disassembly no code is affected.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
arch/x86/include/asm/page_64.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -47,7 +47,7 @@ static inline void clear_page(void *page)
clear_page_erms, X86_FEATURE_ERMS,
"=D" (page),
"0" (page)
- : "memory", "rax", "rcx");
+ : "cc", "memory", "rax", "rcx");
}
void copy_page(void *to, void *from);
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] x86_64: clobber flags in clear_page()
2018-01-13 18:50 [PATCH] x86_64: clobber flags in clear_page() Alexey Dobriyan
@ 2018-02-10 21:19 ` Borislav Petkov
2018-02-13 16:59 ` [tip:x86/asm] x86/asm: Clobber " tip-bot for Alexey Dobriyan
1 sibling, 0 replies; 3+ messages in thread
From: Borislav Petkov @ 2018-02-10 21:19 UTC (permalink / raw)
To: Alexey Dobriyan; +Cc: tglx, mingo, hpa, x86, linux-kernel
On Sat, Jan 13, 2018 at 09:50:48PM +0300, Alexey Dobriyan wrote:
> All clear_page() implementations use XOR which resets flags.
>
> Judging by allyesconfig disassembly no code is affected.
>
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> ---
>
> arch/x86/include/asm/page_64.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/arch/x86/include/asm/page_64.h
> +++ b/arch/x86/include/asm/page_64.h
> @@ -47,7 +47,7 @@ static inline void clear_page(void *page)
> clear_page_erms, X86_FEATURE_ERMS,
> "=D" (page),
> "0" (page)
> - : "memory", "rax", "rcx");
> + : "cc", "memory", "rax", "rcx");
> }
>
> void copy_page(void *to, void *from);
Reviewed-by: Borislav Petkov <bp@suse.de>
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--
^ permalink raw reply [flat|nested] 3+ messages in thread* [tip:x86/asm] x86/asm: Clobber flags in clear_page()
2018-01-13 18:50 [PATCH] x86_64: clobber flags in clear_page() Alexey Dobriyan
2018-02-10 21:19 ` Borislav Petkov
@ 2018-02-13 16:59 ` tip-bot for Alexey Dobriyan
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot for Alexey Dobriyan @ 2018-02-13 16:59 UTC (permalink / raw)
To: linux-tip-commits
Cc: mingo, peterz, adobriyan, hpa, linux-kernel, tglx, bp, torvalds
Commit-ID: 1acdbf7ea8a80706561013346d281d282a3c00f9
Gitweb: https://git.kernel.org/tip/1acdbf7ea8a80706561013346d281d282a3c00f9
Author: Alexey Dobriyan <adobriyan@gmail.com>
AuthorDate: Sat, 13 Jan 2018 21:50:48 +0300
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 13 Feb 2018 17:36:49 +0100
x86/asm: Clobber flags in clear_page()
All clear_page() implementations use XOR which resets flags.
Judging by allyesconfig disassembly no code is affected.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180113185048.GA23111@avx2
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/page_64.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 4baa6bc..f8a85c6 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -47,7 +47,7 @@ static inline void clear_page(void *page)
clear_page_erms, X86_FEATURE_ERMS,
"=D" (page),
"0" (page)
- : "memory", "rax", "rcx");
+ : "cc", "memory", "rax", "rcx");
}
void copy_page(void *to, void *from);
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2018-01-13 18:50 [PATCH] x86_64: clobber flags in clear_page() Alexey Dobriyan
2018-02-10 21:19 ` Borislav Petkov
2018-02-13 16:59 ` [tip:x86/asm] x86/asm: Clobber " tip-bot for Alexey Dobriyan
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