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 --- arch/x86_64/lib/Makefile | 2 +- arch/x86_64/lib/msr-on-cpu.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) create mode 100644 arch/x86_64/lib/msr-on-cpu.c (limited to 'arch/x86_64/lib') diff --git a/arch/x86_64/lib/Makefile b/arch/x86_64/lib/Makefile index b78d4170fce2..0a43f07b0290 100644 --- a/arch/x86_64/lib/Makefile +++ b/arch/x86_64/lib/Makefile @@ -4,7 +4,7 @@ CFLAGS_csum-partial.o := -funroll-loops -obj-y := io.o iomap_copy.o +obj-y := io.o iomap_copy.o msr-on-cpu.o lib-y := csum-partial.o csum-copy.o csum-wrappers.o delay.o \ usercopy.o getuser.o putuser.o \ diff --git a/arch/x86_64/lib/msr-on-cpu.c b/arch/x86_64/lib/msr-on-cpu.c new file mode 100644 index 000000000000..47e0ec47c376 --- /dev/null +++ b/arch/x86_64/lib/msr-on-cpu.c @@ -0,0 +1 @@ +#include "../../i386/lib/msr-on-cpu.c" -- cgit v1.2.2