From b077ffb3b767c3efb44d00b998385a9cb127255c Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Fri, 16 Feb 2007 01:48:11 -0800 Subject: rdmsr_on_cpu, wrmsr_on_cpu There was OpenVZ specific bug rendering some cpufreq drivers unusable on SMP. In short, when cpufreq code thinks it confined itself to needed cpu by means of set_cpus_allowed() to execute rdmsr, some "virtual cpu" feature can migrate process to anywhere. This triggers bugons and does wrong things in general. This got fixed by introducing rdmsr_on_cpu and wrmsr_on_cpu executing rdmsr and wrmsr on given physical cpu by means of smp_call_function_single(). Dave Jones mentioned cpufreq might be not only user of rdmsr_on_cpu() and wrmsr_on_cpu(), so I'm putting them into arch/{i386,x86_64}/lib/ . Signed-off-by: Alexey Dobriyan Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Dave Jones --- include/asm-i386/msr.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/asm-i386') diff --git a/include/asm-i386/msr.h b/include/asm-i386/msr.h index 609a3899475..3516a1fb38e 100644 --- a/include/asm-i386/msr.h +++ b/include/asm-i386/msr.h @@ -83,6 +83,9 @@ static inline void wrmsrl (unsigned long msr, unsigned long long val) : "c" (counter)) #endif /* !CONFIG_PARAVIRT */ +void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h); +void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h); + /* symbolic names for some interesting MSRs */ /* Intel defined MSRs. */ #define MSR_IA32_P5_MC_ADDR 0 -- cgit v1.2.2 From b44755cfaa72e7ed3d831a946bb4e7dfe7548966 Mon Sep 17 00:00:00 2001 From: Adrian Bunk Date: Tue, 20 Feb 2007 01:07:13 +0100 Subject: {rd,wr}msr_on_cpu SMP=n optimization Let's save a few bytes in the CONFIG_SMP=n case. Signed-off-by: Adrian Bunk Signed-off-by: Dave Jones --- include/asm-i386/msr.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/asm-i386') diff --git a/include/asm-i386/msr.h b/include/asm-i386/msr.h index 3516a1fb38e..8c35f3d90a8 100644 --- a/include/asm-i386/msr.h +++ b/include/asm-i386/msr.h @@ -83,8 +83,19 @@ static inline void wrmsrl (unsigned long msr, unsigned long long val) : "c" (counter)) #endif /* !CONFIG_PARAVIRT */ +#ifdef CONFIG_SMP void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h); void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h); +#else /* CONFIG_SMP */ +static inline void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h) +{ + rdmsr(msr_no, *l, *h); +} +static inline void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h) +{ + wrmsr(msr_no, l, h); +} +#endif /* CONFIG_SMP */ /* symbolic names for some interesting MSRs */ /* Intel defined MSRs. */ -- cgit v1.2.2