1 files changed, 59 insertions, 16 deletions

diff --git a/arch/x86/lib/msr.c b/arch/x86/lib/msr.c
index 1440b9c0547e..33a1e3ca22d8 100644
--- a/arch/x86/lib/msr.c
+++ b/arch/x86/lib/msr.c
@@ -89,16 +89,13 @@ void rdmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs)
 	rv.msrs	  = msrs;
 	rv.msr_no = msr_no;
 
-	preempt_disable();
-	/*
-	 * FIXME: handle the CPU we're executing on separately for now until
-	 * smp_call_function_many has been fixed to not skip it.
-	 */
-	this_cpu = raw_smp_processor_id();
-	smp_call_function_single(this_cpu, __rdmsr_on_cpu, &rv, 1);
+	this_cpu = get_cpu();
+
+	if (cpumask_test_cpu(this_cpu, mask))
+		__rdmsr_on_cpu(&rv);
 
 	smp_call_function_many(mask, __rdmsr_on_cpu, &rv, 1);
-	preempt_enable();
+	put_cpu();
 }
 EXPORT_SYMBOL(rdmsr_on_cpus);
 
@@ -121,16 +118,13 @@ void wrmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs)
 	rv.msrs   = msrs;
 	rv.msr_no = msr_no;
 
-	preempt_disable();
-	/*
-	 * FIXME: handle the CPU we're executing on separately for now until
-	 * smp_call_function_many has been fixed to not skip it.
-	 */
-	this_cpu = raw_smp_processor_id();
-	smp_call_function_single(this_cpu, __wrmsr_on_cpu, &rv, 1);
+	this_cpu = get_cpu();
+
+	if (cpumask_test_cpu(this_cpu, mask))
+		__wrmsr_on_cpu(&rv);
 
 	smp_call_function_many(mask, __wrmsr_on_cpu, &rv, 1);
-	preempt_enable();
+	put_cpu();
 }
 EXPORT_SYMBOL(wrmsr_on_cpus);
 
@@ -181,3 +175,52 @@ int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
 	return err ? err : rv.err;
 }
 EXPORT_SYMBOL(wrmsr_safe_on_cpu);
+
+/*
+ * These variants are significantly slower, but allows control over
+ * the entire 32-bit GPR set.
+ */
+struct msr_regs_info {
+	u32 *regs;
+	int err;
+};
+
+static void __rdmsr_safe_regs_on_cpu(void *info)
+{
+	struct msr_regs_info *rv = info;
+
+	rv->err = rdmsr_safe_regs(rv->regs);
+}
+
+static void __wrmsr_safe_regs_on_cpu(void *info)
+{
+	struct msr_regs_info *rv = info;
+
+	rv->err = wrmsr_safe_regs(rv->regs);
+}
+
+int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 *regs)
+{
+	int err;
+	struct msr_regs_info rv;
+
+	rv.regs   = regs;
+	rv.err    = -EIO;
+	err = smp_call_function_single(cpu, __rdmsr_safe_regs_on_cpu, &rv, 1);
+
+	return err ? err : rv.err;
+}
+EXPORT_SYMBOL(rdmsr_safe_regs_on_cpu);
+
+int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 *regs)
+{
+	int err;
+	struct msr_regs_info rv;
+
+	rv.regs = regs;
+	rv.err  = -EIO;
+	err = smp_call_function_single(cpu, __wrmsr_safe_regs_on_cpu, &rv, 1);
+
+	return err ? err : rv.err;
+}
+EXPORT_SYMBOL(wrmsr_safe_regs_on_cpu);