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authorAlexey Dobriyan <adobriyan@openvz.org>2007-02-16 04:48:11 -0500
committerDave Jones <davej@redhat.com>2007-02-20 14:23:43 -0500
commitb077ffb3b767c3efb44d00b998385a9cb127255c (patch)
tree160369b5541142afedc20a97a9c89718550cf2a3 /include/asm-x86_64
parent22f7bb0329a506f2fd61c14ce3c8bc632e08c732 (diff)
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 <adobriyan@openvz.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'include/asm-x86_64')
-rw-r--r--include/asm-x86_64/msr.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/asm-x86_64/msr.h b/include/asm-x86_64/msr.h
index 3227bc93d69b..995a2b5fb26b 100644
--- a/include/asm-x86_64/msr.h
+++ b/include/asm-x86_64/msr.h
@@ -160,6 +160,8 @@ static inline unsigned int cpuid_edx(unsigned int op)
160#define MSR_IA32_UCODE_WRITE 0x79 160#define MSR_IA32_UCODE_WRITE 0x79
161#define MSR_IA32_UCODE_REV 0x8b 161#define MSR_IA32_UCODE_REV 0x8b
162 162
163void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
164void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
163 165
164#endif 166#endif
165 167