2 files changed, 71 insertions, 108 deletions

diff --git a/arch/i386/kernel/msr.c b/arch/i386/kernel/msr.c
index bcaa6e9b6197..8cd0a91ce107 100644
--- a/arch/i386/kernel/msr.c
+++ b/arch/i386/kernel/msr.c
@@ -45,104 +45,6 @@
 
 static struct class *msr_class;
 
-static inline int wrmsr_eio(u32 reg, u32 eax, u32 edx)
-{
-        int err;
-
-        err = wrmsr_safe(reg, eax, edx);
-        if (err)
-                err = -EIO;
-        return err;
-}
-
-static inline int rdmsr_eio(u32 reg, u32 *eax, u32 *edx)
-{
-        int err;
-
-        err = rdmsr_safe(reg, eax, edx);
-        if (err)
-                err = -EIO;
-        return err;
-}
-
-#ifdef CONFIG_SMP
-
-struct msr_command {
-        int err;
-        u32 reg;
-        u32 data[2];
-};
-
-static void msr_smp_wrmsr(void *cmd_block)
-{
-        struct msr_command *cmd = (struct msr_command *)cmd_block;
-
-        cmd->err = wrmsr_eio(cmd->reg, cmd->data[0], cmd->data[1]);
-}
-
-static void msr_smp_rdmsr(void *cmd_block)
-{
-        struct msr_command *cmd = (struct msr_command *)cmd_block;
-
-        cmd->err = rdmsr_eio(cmd->reg, &cmd->data[0], &cmd->data[1]);
-}
-
-static inline int do_wrmsr(int cpu, u32 reg, u32 eax, u32 edx)
-{
-        struct msr_command cmd;
-        int ret;
-
-        preempt_disable();
-        if (cpu == smp_processor_id()) {
-                ret = wrmsr_eio(reg, eax, edx);
-        } else {
-                cmd.reg = reg;
-                cmd.data[0] = eax;
-                cmd.data[1] = edx;
-
-                smp_call_function_single(cpu, msr_smp_wrmsr, &cmd, 1, 1);
-                ret = cmd.err;
-        }
-        preempt_enable();
-        return ret;
-}
-
-static inline int do_rdmsr(int cpu, u32 reg, u32 * eax, u32 * edx)
-{
-        struct msr_command cmd;
-        int ret;
-
-        preempt_disable();
-        if (cpu == smp_processor_id()) {
-                ret = rdmsr_eio(reg, eax, edx);
-        } else {
-                cmd.reg = reg;
-
-                smp_call_function_single(cpu, msr_smp_rdmsr, &cmd, 1, 1);
-
-                *eax = cmd.data[0];
-                *edx = cmd.data[1];
-
-                ret = cmd.err;
-        }
-        preempt_enable();
-        return ret;
-}
-
-#else                           /* ! CONFIG_SMP */
-
-static inline int do_wrmsr(int cpu, u32 reg, u32 eax, u32 edx)
-{
-        return wrmsr_eio(reg, eax, edx);
-}
-
-static inline int do_rdmsr(int cpu, u32 reg, u32 *eax, u32 *edx)
-{
-        return rdmsr_eio(reg, eax, edx);
-}
-
-#endif                          /* ! CONFIG_SMP */
-
 static loff_t msr_seek(struct file *file, loff_t offset, int orig)
 {
         loff_t ret = -EINVAL;
@@ -174,9 +76,9 @@ static ssize_t msr_read(struct file *file, char __user * buf,
                 return -EINVAL; /* Invalid chunk size */
 
         for (; count; count -= 8) {
-                err = do_rdmsr(cpu, reg, &data[0], &data[1]);
+                err = rdmsr_safe_on_cpu(cpu, reg, &data[0], &data[1]);
                 if (err)
-                        return err;
+                        return -EIO;
                 if (copy_to_user(tmp, &data, 8))
                         return -EFAULT;
                 tmp += 2;
@@ -200,9 +102,9 @@ static ssize_t msr_write(struct file *file, const char __user *buf,
         for (; count; count -= 8) {
                 if (copy_from_user(&data, tmp, 8))
                         return -EFAULT;
-                err = do_wrmsr(cpu, reg, data[0], data[1]);
+                err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]);
                 if (err)
-                        return err;
+                        return -EIO;
                 tmp += 2;
         }
 
diff --git a/arch/i386/lib/msr-on-cpu.c b/arch/i386/lib/msr-on-cpu.c
index 1c46bda409ff..7767962f25d3 100644
--- a/arch/i386/lib/msr-on-cpu.c
+++ b/arch/i386/lib/msr-on-cpu.c
@@ -6,6 +6,7 @@
 struct msr_info {
         u32 msr_no;
         u32 l, h;
+        int err;
 };
 
 static void __rdmsr_on_cpu(void *info)
@@ -15,20 +16,38 @@ static void __rdmsr_on_cpu(void *info)
         rdmsr(rv->msr_no, rv->l, rv->h);
 }
 
-void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+static void __rdmsr_safe_on_cpu(void *info)
 {
+        struct msr_info *rv = info;
+
+        rv->err = rdmsr_safe(rv->msr_no, &rv->l, &rv->h);
+}
+
+static int _rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h, int safe)
+{
+        int err = 0;
         preempt_disable();
         if (smp_processor_id() == cpu)
-                rdmsr(msr_no, *l, *h);
+                if (safe)
+                        err = rdmsr_safe(msr_no, l, h);
+                else
+                        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);
+                if (safe) {
+                        smp_call_function_single(cpu, __rdmsr_safe_on_cpu,
+                                                 &rv, 0, 1);
+                        err = rv.err;
+                } else {
+                        smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 0, 1);
+                }
                 *l = rv.l;
                 *h = rv.h;
         }
         preempt_enable();
+        return err;
 }
 
 static void __wrmsr_on_cpu(void *info)
@@ -38,21 +57,63 @@ static void __wrmsr_on_cpu(void *info)
         wrmsr(rv->msr_no, rv->l, rv->h);
 }
 
-void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+static void __wrmsr_safe_on_cpu(void *info)
 {
+        struct msr_info *rv = info;
+
+        rv->err = wrmsr_safe(rv->msr_no, rv->l, rv->h);
+}
+
+static int _wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h, int safe)
+{
+        int err = 0;
         preempt_disable();
         if (smp_processor_id() == cpu)
-                wrmsr(msr_no, l, h);
+                if (safe)
+                        err = wrmsr_safe(msr_no, l, h);
+                else
+                        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);
+                if (safe) {
+                        smp_call_function_single(cpu, __wrmsr_safe_on_cpu,
+                                                 &rv, 0, 1);
+                        err = rv.err;
+                } else {
+                        smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 0, 1);
+                }
         }
         preempt_enable();
+        return err;
+}
+
+void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+        _wrmsr_on_cpu(cpu, msr_no, l, h, 0);
+}
+
+void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+        _rdmsr_on_cpu(cpu, msr_no, l, h, 0);
+}
+
+/* These "safe" variants are slower and should be used when the target MSR
+   may not actually exist. */
+int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+        return _wrmsr_on_cpu(cpu, msr_no, l, h, 1);
+}
+
+int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+        return _rdmsr_on_cpu(cpu, msr_no, l, h, 1);
 }
 
 EXPORT_SYMBOL(rdmsr_on_cpu);
 EXPORT_SYMBOL(wrmsr_on_cpu);
+EXPORT_SYMBOL(rdmsr_safe_on_cpu);
+EXPORT_SYMBOL(wrmsr_safe_on_cpu);