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Message-ID: <tip-d59fe3f13d070489e63d04e1c9bfd819d5f71542@git.kernel.org> Date: Thu, 24 Jan 2013 12:06:18 -0800 From: tip-bot for Jan Beulich <JBeulich@...e.com> To: linux-tip-commits@...r.kernel.org Cc: linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org, torvalds@...ux-foundation.org, jbeulich@...e.com, viro@...iv.linux.org.uk, akpm@...ux-foundation.org, JBeulich@...e.com, tglx@...utronix.de, roland@...k.frob.com Subject: [tip:x86/asm] ix86: Tighten asmlinkage_protect() constraints Commit-ID: d59fe3f13d070489e63d04e1c9bfd819d5f71542 Gitweb: http://git.kernel.org/tip/d59fe3f13d070489e63d04e1c9bfd819d5f71542 Author: Jan Beulich <JBeulich@...e.com> AuthorDate: Tue, 22 Jan 2013 11:24:12 +0000 Committer: Ingo Molnar <mingo@...nel.org> CommitDate: Thu, 24 Jan 2013 11:25:59 +0100 ix86: Tighten asmlinkage_protect() constraints While the description of the commit that originally introduced asmlinkage_protect() validly says that this doesn't guarantee clobbering of the function arguments, using "m" constraints rather than "g" ones reduces the risk (by making it less attractive to the compiler to move those variables into registers) and generally results in better code (because we know the arguments are in memory anyway, and are frequently - if not always - used just once, with the second [compiler visible] use in asmlinkage_protect() itself being a fake one). Signed-off-by: Jan Beulich <jbeulich@...e.com> Cc: <roland@...k.frob.com> Cc: <viro@...iv.linux.org.uk> Cc: Linus Torvalds <torvalds@...ux-foundation.org> Cc: Andrew Morton <akpm@...ux-foundation.org> Link: http://lkml.kernel.org/r/50FE84EC02000078000B83B7@nat28.tlf.novell.com Signed-off-by: Ingo Molnar <mingo@...nel.org> --- arch/x86/include/asm/linkage.h | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h index 4814297..79327e9 100644 --- a/arch/x86/include/asm/linkage.h +++ b/arch/x86/include/asm/linkage.h @@ -27,20 +27,20 @@ #define __asmlinkage_protect0(ret) \ __asmlinkage_protect_n(ret) #define __asmlinkage_protect1(ret, arg1) \ - __asmlinkage_protect_n(ret, "g" (arg1)) + __asmlinkage_protect_n(ret, "m" (arg1)) #define __asmlinkage_protect2(ret, arg1, arg2) \ - __asmlinkage_protect_n(ret, "g" (arg1), "g" (arg2)) + __asmlinkage_protect_n(ret, "m" (arg1), "m" (arg2)) #define __asmlinkage_protect3(ret, arg1, arg2, arg3) \ - __asmlinkage_protect_n(ret, "g" (arg1), "g" (arg2), "g" (arg3)) + __asmlinkage_protect_n(ret, "m" (arg1), "m" (arg2), "m" (arg3)) #define __asmlinkage_protect4(ret, arg1, arg2, arg3, arg4) \ - __asmlinkage_protect_n(ret, "g" (arg1), "g" (arg2), "g" (arg3), \ - "g" (arg4)) + __asmlinkage_protect_n(ret, "m" (arg1), "m" (arg2), "m" (arg3), \ + "m" (arg4)) #define __asmlinkage_protect5(ret, arg1, arg2, arg3, arg4, arg5) \ - __asmlinkage_protect_n(ret, "g" (arg1), "g" (arg2), "g" (arg3), \ - "g" (arg4), "g" (arg5)) + __asmlinkage_protect_n(ret, "m" (arg1), "m" (arg2), "m" (arg3), \ + "m" (arg4), "m" (arg5)) #define __asmlinkage_protect6(ret, arg1, arg2, arg3, arg4, arg5, arg6) \ - __asmlinkage_protect_n(ret, "g" (arg1), "g" (arg2), "g" (arg3), \ - "g" (arg4), "g" (arg5), "g" (arg6)) + __asmlinkage_protect_n(ret, "m" (arg1), "m" (arg2), "m" (arg3), \ + "m" (arg4), "m" (arg5), "m" (arg6)) #endif /* CONFIG_X86_32 */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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