2 files changed, 72 insertions, 0 deletions
diff --git a/arch/i386/lib/Makefile b/arch/i386/lib/Makefile
index d86a548b8d54..0d41223472c2 100644
--- a/arch/i386/lib/Makefile
+++ b/arch/i386/lib/Makefile
@@ -7,3 +7,5 @@ lib-y = checksum.o delay.o usercopy.o getuser.o putuser.o memcpy.o strstr.o \
 	bitops.o semaphore.o
 
 lib-$(CONFIG_X86_USE_3DNOW) += mmx.o
+
+obj-y = msr-on-cpu.o
diff --git a/arch/i386/lib/msr-on-cpu.c b/arch/i386/lib/msr-on-cpu.c
new file mode 100644
index 000000000000..2092ea15ba85
--- /dev/null
+++ b/arch/i386/lib/msr-on-cpu.c
@@ -0,0 +1,70 @@
+#include <linux/module.h>
+#include <linux/preempt.h>
+#include <linux/smp.h>
+#include <asm/msr.h>
+
+#ifdef CONFIG_SMP
+struct msr_info {
+	u32 msr_no;
+	u32 l, h;
+};
+
+static void __rdmsr_on_cpu(void *info)
+{
+	struct msr_info *rv = info;
+
+	rdmsr(rv->msr_no, rv->l, rv->h);
+}
+
+void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+	preempt_disable();
+	if (smp_processor_id() == cpu)
+		rdmsr(msr_no, *l, *h);
+	else {
+		struct msr_info rv;
+
+		rv.msr_no = msr_no;
+		smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 0, 1);
+		*l = rv.l;
+		*h = rv.h;
+	}
+	preempt_enable();
+}
+
+static void __wrmsr_on_cpu(void *info)
+{
+	struct msr_info *rv = info;
+
+	wrmsr(rv->msr_no, rv->l, rv->h);
+}
+
+void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+	preempt_disable();
+	if (smp_processor_id() == cpu)
+		wrmsr(msr_no, l, h);
+	else {
+		struct msr_info rv;
+
+		rv.msr_no = msr_no;
+		rv.l = l;
+		rv.h = h;
+		smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 0, 1);
+	}
+	preempt_enable();
+}
+#else
+void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+	rdmsr(msr_no, *l, *h);
+}
+
+void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+	wrmsr(msr_no, l, h);
+}
+#endif
+
+EXPORT_SYMBOL(rdmsr_on_cpu);
+EXPORT_SYMBOL(wrmsr_on_cpu);