1 files changed, 72 insertions, 145 deletions

diff --git a/arch/x86/lib/msr.c b/arch/x86/lib/msr.c
index 1440b9c0547..43623739c7c 100644
--- a/arch/x86/lib/msr.c
+++ b/arch/x86/lib/msr.c
@@ -1,183 +1,110 @@
 #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 *msrs_alloc(void)
 {
-	struct msr_info *rv = info;
-	struct msr *reg;
-	int this_cpu = raw_smp_processor_id();
+	struct msr *msrs = NULL;
 
-	if (rv->msrs)
-		reg = &rv->msrs[this_cpu - rv->off];
-	else
-		reg = &rv->reg;
+	msrs = alloc_percpu(struct msr);
+	if (!msrs) {
+		pr_warn("%s: error allocating msrs\n", __func__);
+		return NULL;
+	}
 
-	rdmsr(rv->msr_no, reg->l, reg->h);
+	return msrs;
 }
+EXPORT_SYMBOL(msrs_alloc);
 
-static void __wrmsr_on_cpu(void *info)
+void msrs_free(struct msr *msrs)
 {
-	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);
+	free_percpu(msrs);
 }
+EXPORT_SYMBOL(msrs_free);
 
-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)
+/**
+ * Read an MSR with error handling
+ *
+ * @msr: MSR to read
+ * @m: value to read into
+ *
+ * It returns read data only on success, otherwise it doesn't change the output
+ * argument @m.
+ *
+ */
+int msr_read(u32 msr, struct msr *m)
 {
 	int err;
-	struct msr_info rv;
+	u64 val;
 
-	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);
+	err = rdmsrl_safe(msr, &val);
+	if (!err)
+		m->q = val;
 
 	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
+/**
+ * Write an MSR with error handling
  *
+ * @msr: MSR to write
+ * @m: value to write
  */
-void rdmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs)
+int msr_write(u32 msr, struct msr *m)
 {
-	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();
+	return wrmsrl_safe(msr, m->q);
 }
-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)
+static inline int __flip_bit(u32 msr, u8 bit, bool set)
 {
-	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;
+	struct msr m, m1;
+	int err = -EINVAL;
 
-	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);
+	if (bit > 63)
+		return err;
 
-	smp_call_function_many(mask, __wrmsr_on_cpu, &rv, 1);
-	preempt_enable();
-}
-EXPORT_SYMBOL(wrmsr_on_cpus);
+	err = msr_read(msr, &m);
+	if (err)
+		return err;
 
-/* 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;
+	m1 = m;
+	if (set)
+		m1.q |=  BIT_64(bit);
+	else
+		m1.q &= ~BIT_64(bit);
 
-	rv->err = rdmsr_safe(rv->msr_no, &rv->reg.l, &rv->reg.h);
-}
+	if (m1.q == m.q)
+		return 0;
 
-static void __wrmsr_safe_on_cpu(void *info)
-{
-	struct msr_info *rv = info;
+	err = msr_write(msr, &m1);
+	if (err)
+		return err;
 
-	rv->err = wrmsr_safe(rv->msr_no, rv->reg.l, rv->reg.h);
+	return 1;
 }
 
-int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+/**
+ * Set @bit in a MSR @msr.
+ *
+ * Retval:
+ * < 0: An error was encountered.
+ * = 0: Bit was already set.
+ * > 0: Hardware accepted the MSR write.
+ */
+int msr_set_bit(u32 msr, u8 bit)
 {
-	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;
+	return __flip_bit(msr, bit, true);
 }
-EXPORT_SYMBOL(rdmsr_safe_on_cpu);
 
-int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+/**
+ * Clear @bit in a MSR @msr.
+ *
+ * Retval:
+ * < 0: An error was encountered.
+ * = 0: Bit was already cleared.
+ * > 0: Hardware accepted the MSR write.
+ */
+int msr_clear_bit(u32 msr, u8 bit)
 {
-	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;
+	return __flip_bit(msr, bit, false);
 }
-EXPORT_SYMBOL(wrmsr_safe_on_cpu);