| Date | Fri, 21 Mar 2008 15:43:48 -0700 | From | Chris Wright <> | Subject | [patch 58/76] x86: dont use P6_NOPs if compiling with CONFIG_X86_GENERIC |
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-stable review patch. If anyone has any objections, please let us know. ---------------------
From: H. Peter Anvin <hpa@zytor.com>
x86: don't use P6_NOPs if compiling with CONFIG_X86_GENERIC
P6_NOPs are definitely not supported on some VIA CPUs, and possibly (unverified) on AMD K7s. It is also the only thing that prevents a 686 kernel from running on Transmeta TM3x00/5x00 (Crusoe) series.
The performance benefit over generic NOPs is very small, so when building for generic consumption, avoid using them.
Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [cebbert@redhat.com: backport take 2, with parens this time] Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> ---
include/asm-x86/processor_32.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/include/asm-x86/processor_32.h +++ b/include/asm-x86/processor_32.h @@ -712,9 +712,10 @@ static inline unsigned int cpuid_edx(uns #define ASM_NOP6 K7_NOP6 #define ASM_NOP7 K7_NOP7 #define ASM_NOP8 K7_NOP8 -#elif defined(CONFIG_M686) || defined(CONFIG_MPENTIUMII) || \ +#elif (defined(CONFIG_M686) || defined(CONFIG_MPENTIUMII) || \ defined(CONFIG_MPENTIUMIII) || defined(CONFIG_MPENTIUMM) || \ - defined(CONFIG_MCORE2) || defined(CONFIG_PENTIUM4) + defined(CONFIG_MCORE2) || defined(CONFIG_PENTIUM4)) && \ + !defined(CONFIG_X86_GENERIC) #define ASM_NOP1 P6_NOP1 #define ASM_NOP2 P6_NOP2 #define ASM_NOP3 P6_NOP3 --
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