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From: Borislav Petkov <bp@alien8.de>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: X86 ML <x86@kernel.org>,
	Wedson Almeida Filho <wedsonaf@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	LKML <linux-kernel@vger.kernel.org>, Borislav Petkov <bp@suse.de>
Subject: [PATCH] x86, cpufeature: Use new CC_HAVE_ASM_GOTO
Date: Fri, 28 Jun 2013 18:41:41 +0200	[thread overview]
Message-ID: <1372437701-13351-1-git-send-email-bp@alien8.de> (raw)
In-Reply-To: <51CD99C2.9040109@zytor.com>

From: Borislav Petkov <bp@suse.de>

... for checking for "asm goto" compiler support. It is more explicit
this way and we cover the cases where distros have backported that
support even to gcc versions < 4.5.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/include/asm/cpufeature.h | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 47538a61c91b..d3f5c63078d8 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -366,9 +366,10 @@ extern bool __static_cpu_has_safe(u16 bit);
  */
 static __always_inline __pure bool __static_cpu_has(u16 bit)
 {
-#if __GNUC__ > 4 || __GNUC_MINOR__ >= 5
+#ifdef CC_HAVE_ASM_GOTO
 
 #ifdef CONFIG_X86_DEBUG_STATIC_CPU_HAS
+
 		/*
 		 * Catch too early usage of this before alternatives
 		 * have run.
@@ -384,6 +385,7 @@ static __always_inline __pure bool __static_cpu_has(u16 bit)
 			 ".previous\n"
 			 /* skipping size check since replacement size = 0 */
 			 : : "i" (X86_FEATURE_ALWAYS) : : t_warn);
+
 #endif
 
 		asm goto("1: jmp %l[t_no]\n"
@@ -406,7 +408,9 @@ static __always_inline __pure bool __static_cpu_has(u16 bit)
 		warn_pre_alternatives();
 		return false;
 #endif
-#else /* GCC_VERSION >= 40500 */
+
+#else /* CC_HAVE_ASM_GOTO */
+
 		u8 flag;
 		/* Open-coded due to __stringify() in ALTERNATIVE() */
 		asm volatile("1: movb $0,%0\n"
@@ -427,7 +431,8 @@ static __always_inline __pure bool __static_cpu_has(u16 bit)
 			     ".previous\n"
 			     : "=qm" (flag) : "i" (bit));
 		return flag;
-#endif
+
+#endif /* CC_HAVE_ASM_GOTO */
 }
 
 #define static_cpu_has(bit)					\
@@ -441,7 +446,7 @@ static __always_inline __pure bool __static_cpu_has(u16 bit)
 
 static __always_inline __pure bool _static_cpu_has_safe(u16 bit)
 {
-#if __GNUC__ > 4 || __GNUC_MINOR__ >= 5
+#ifdef CC_HAVE_ASM_GOTO
 /*
  * We need to spell the jumps to the compiler because, depending on the offset,
  * the replacement jump can be bigger than the original jump, and this we cannot
@@ -475,7 +480,7 @@ static __always_inline __pure bool _static_cpu_has_safe(u16 bit)
 		return false;
 	t_dynamic:
 		return __static_cpu_has_safe(bit);
-#else /* GCC_VERSION >= 40500 */
+#else
 		u8 flag;
 		/* Open-coded due to __stringify() in ALTERNATIVE() */
 		asm volatile("1: movb $2,%0\n"
@@ -511,7 +516,7 @@ static __always_inline __pure bool _static_cpu_has_safe(u16 bit)
 			     : "=qm" (flag)
 			     : "i" (bit), "i" (X86_FEATURE_ALWAYS));
 		return (flag == 2 ? __static_cpu_has_safe(bit) : flag);
-#endif
+#endif /* CC_HAVE_ASM_GOTO */
 }
 
 #define static_cpu_has_safe(bit)				\
-- 
1.8.3


  parent reply	other threads:[~2013-06-28 16:41 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-28 10:54 [PATCH] x86: Use asm-goto to implement mutex fast path on x86-64 Wedson Almeida Filho
2013-06-28 11:19 ` Ingo Molnar
2013-06-28 14:09   ` Borislav Petkov
2013-06-28 14:12     ` H. Peter Anvin
2013-06-28 15:15       ` Peter Zijlstra
2013-06-28 16:41       ` Borislav Petkov [this message]
2013-07-05 14:24         ` [tip:x86/cpu] x86, cpufeature: Use new CC_HAVE_ASM_GOTO tip-bot for Borislav Petkov
2013-06-29 23:56     ` [PATCH] x86: Use asm-goto to implement mutex fast path on x86-64 Wedson Almeida Filho
2013-06-30 22:00       ` Borislav Petkov
2013-07-01  7:50         ` Ingo Molnar
2013-07-01 10:23           ` Borislav Petkov
2013-07-01 11:11             ` Ingo Molnar
2013-07-01 12:29               ` Borislav Petkov
2013-07-01 12:50                 ` Ingo Molnar
2013-07-01 14:48                   ` Borislav Petkov
2013-07-01 22:28                     ` Borislav Petkov
2013-07-01 22:35                       ` Wedson Almeida Filho
2013-07-01 22:44                         ` Borislav Petkov
2013-07-02  6:39                           ` Ingo Molnar
2013-07-02 10:29                             ` Borislav Petkov
2013-07-01 14:30             ` H. Peter Anvin
2013-07-01 14:36               ` Borislav Petkov
2013-07-01 14:45                 ` H. Peter Anvin
2013-07-01 14:50                   ` Borislav Petkov

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