From 62122fd7dadac09704782d8bc051fb898a0272bd Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Fri, 28 Jun 2013 18:41:41 +0200 Subject: [PATCH 1/2] x86, cpufeature: Use new CC_HAVE_ASM_GOTO ... 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 Link: http://lkml.kernel.org/r/1372437701-13351-1-git-send-email-bp@alien8.de Signed-off-by: H. Peter Anvin --- 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) \ From 237d1548543312fcc8c99d302ab68fbf8ef6f97f Mon Sep 17 00:00:00 2001 From: Wang YanQing Date: Fri, 28 Jun 2013 22:45:16 +0800 Subject: [PATCH 2/2] x86: Fix override new_cpu_data.x86 with 486 We should set X86 to 486 before use cpuid to detect the cpu type, if we set X86 to 486 after cpuid, then we will get 486 until cpu_detect runs. Signed-off-by: Wang YanQing Link: http://lkml.kernel.org/r/20130628144516.GA2177@udknight Acked-by: Borislav Petkov Signed-off-by: H. Peter Anvin --- arch/x86/kernel/head_32.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index e65ddc62e113..fe79573c84b9 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -410,6 +410,7 @@ enable_paging: /* * Check if it is 486 */ + movb $4,X86 # at least 486 cmpl $-1,X86_CPUID je is486 @@ -437,7 +438,6 @@ enable_paging: movl %edx,X86_CAPABILITY is486: - movb $4,X86 movl $0x50022,%ecx # set AM, WP, NE and MP movl %cr0,%eax andl $0x80000011,%eax # Save PG,PE,ET