1 files changed, 183 insertions, 0 deletions

diff --git a/arch/x86/lib/msr.c b/arch/x86/lib/msr.c
new file mode 100644
index 000000000000..1440b9c0547e
--- /dev/null
+++ b/arch/x86/lib/msr.c
@@ -0,0 +1,183 @@
+#include <linux/module.h>
+#include <linux/preempt.h>
+#include <linux/smp.h>
+#include <asm/msr.h>
+
+struct msr_info {
+        u32 msr_no;
+        struct msr reg;
+        struct msr *msrs;
+        int off;
+        int err;
+};
+
+static void __rdmsr_on_cpu(void *info)
+{
+        struct msr_info *rv = info;
+        struct msr *reg;
+        int this_cpu = raw_smp_processor_id();
+
+        if (rv->msrs)
+                reg = &rv->msrs[this_cpu - rv->off];
+        else
+                reg = &rv->reg;
+
+        rdmsr(rv->msr_no, reg->l, reg->h);
+}
+
+static void __wrmsr_on_cpu(void *info)
+{
+        struct msr_info *rv = info;
+        struct msr *reg;
+        int this_cpu = raw_smp_processor_id();
+
+        if (rv->msrs)
+                reg = &rv->msrs[this_cpu - rv->off];
+        else
+                reg = &rv->reg;
+
+        wrmsr(rv->msr_no, reg->l, reg->h);
+}
+
+int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+        int err;
+        struct msr_info rv;
+
+        memset(&rv, 0, sizeof(rv));
+
+        rv.msr_no = msr_no;
+        err = smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 1);
+        *l = rv.reg.l;
+        *h = rv.reg.h;
+
+        return err;
+}
+EXPORT_SYMBOL(rdmsr_on_cpu);
+
+int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+        int err;
+        struct msr_info rv;
+
+        memset(&rv, 0, sizeof(rv));
+
+        rv.msr_no = msr_no;
+        rv.reg.l = l;
+        rv.reg.h = h;
+        err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);
+
+        return err;
+}
+EXPORT_SYMBOL(wrmsr_on_cpu);
+
+/* rdmsr on a bunch of CPUs
+ *
+ * @mask:       which CPUs
+ * @msr_no:     which MSR
+ * @msrs:       array of MSR values
+ *
+ */
+void rdmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs)
+{
+        struct msr_info rv;
+        int this_cpu;
+
+        memset(&rv, 0, sizeof(rv));
+
+        rv.off    = cpumask_first(mask);
+        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);
+
+        smp_call_function_many(mask, __rdmsr_on_cpu, &rv, 1);
+        preempt_enable();
+}
+EXPORT_SYMBOL(rdmsr_on_cpus);
+
+/*
+ * wrmsr on a bunch of CPUs
+ *
+ * @mask:       which CPUs
+ * @msr_no:     which MSR
+ * @msrs:       array of MSR values
+ *
+ */
+void wrmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs)
+{
+        struct msr_info rv;
+        int this_cpu;
+
+        memset(&rv, 0, sizeof(rv));
+
+        rv.off    = cpumask_first(mask);
+        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);
+
+        smp_call_function_many(mask, __wrmsr_on_cpu, &rv, 1);
+        preempt_enable();
+}
+EXPORT_SYMBOL(wrmsr_on_cpus);
+
+/* These "safe" variants are slower and should be used when the target MSR
+   may not actually exist. */
+static void __rdmsr_safe_on_cpu(void *info)
+{
+        struct msr_info *rv = info;
+
+        rv->err = rdmsr_safe(rv->msr_no, &rv->reg.l, &rv->reg.h);
+}
+
+static void __wrmsr_safe_on_cpu(void *info)
+{
+        struct msr_info *rv = info;
+
+        rv->err = wrmsr_safe(rv->msr_no, rv->reg.l, rv->reg.h);
+}
+
+int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+        int err;
+        struct msr_info rv;
+
+        memset(&rv, 0, sizeof(rv));
+
+        rv.msr_no = msr_no;
+        err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1);
+        *l = rv.reg.l;
+        *h = rv.reg.h;
+
+        return err ? err : rv.err;
+}
+EXPORT_SYMBOL(rdmsr_safe_on_cpu);
+
+int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+        int err;
+        struct msr_info rv;
+
+        memset(&rv, 0, sizeof(rv));
+
+        rv.msr_no = msr_no;
+        rv.reg.l = l;
+        rv.reg.h = h;
+        err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1);
+
+        return err ? err : rv.err;
+}
+EXPORT_SYMBOL(wrmsr_safe_on_cpu);