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-rw-r--r--arch/x86/lib/msr.c183
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 0000000..1440b9c
--- /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);
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