x86: msr: propagate errors from smp_call_function_single()

Propagate error (-ENXIO) from smp_call_function_single().  These
errors can happen when a CPU is unplugged while the MSR driver is
open.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index e43938086885c307b5389774dfb114e5ba12b9f1..9c34a1005dba986fbaea969b81aa88676f07741b 100644 (file)
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -79,8 +79,11 @@ static ssize_t msr_read(struct file *file, char __user *buf,
 
        for (; count; count -= 8) {
                err = rdmsr_safe_on_cpu(cpu, reg, &data[0], &data[1]);
-               if (err)
-                       return -EIO;
+               if (err) {
+                       if (err == -EFAULT) /* Fix idiotic error code */
+                               err = -EIO;
+                       return err;
+               }
                if (copy_to_user(tmp, &data, 8))
                        return -EFAULT;
                tmp += 2;
@@ -105,8 +108,11 @@ static ssize_t msr_write(struct file *file, const char __user *buf,
                if (copy_from_user(&data, tmp, 8))
                        return -EFAULT;
                err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]);
-               if (err)
-                       return -EIO;
+               if (err) {
+                       if (err == -EFAULT) /* Fix idiotic error code */
+                               err = -EIO;
+                       return err;
+               }
                tmp += 2;
        }
 

diff --git a/arch/x86/lib/msr-on-cpu.c b/arch/x86/lib/msr-on-cpu.c
index d5a2b39f882b181c8f57e5fc2f7e06dbd50cf570..01b868ba82f8c21fd8384a426236e3a315f82dea 100644 (file)
--- a/arch/x86/lib/msr-on-cpu.c
+++ b/arch/x86/lib/msr-on-cpu.c
@@ -30,10 +30,11 @@ static int _rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h, int safe)
 
        rv.msr_no = msr_no;
        if (safe) {
-               smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1);
-               err = rv.err;
+               err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu,
+                                              &rv, 1);
+               err = err ? err : rv.err;
        } else {
-               smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 1);
+               err = smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 1);
        }
        *l = rv.l;
        *h = rv.h;
@@ -64,23 +65,24 @@ static int _wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h, int safe)
        rv.l = l;
        rv.h = h;
        if (safe) {
-               smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1);
-               err = rv.err;
+               err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu,
+                                              &rv, 1);
+               err = err ? err : rv.err;
        } else {
-               smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);
+               err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);
        }
 
        return err;
 }
 
-void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
 {
-       _wrmsr_on_cpu(cpu, msr_no, l, h, 0);
+       return _wrmsr_on_cpu(cpu, msr_no, l, h, 0);
 }
 
-void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
 {
-       _rdmsr_on_cpu(cpu, msr_no, l, h, 0);
+       return _rdmsr_on_cpu(cpu, msr_no, l, h, 0);
 }
 
 /* These "safe" variants are slower and should be used when the target MSR

diff --git a/include/asm-x86/msr.h b/include/asm-x86/msr.h
index ca110ee73f074cf41550e7d7860eb412b7bb82ed..ad5f2decf7f7b2a5e230cf9250cb786771320363 100644 (file)
--- a/include/asm-x86/msr.h
+++ b/include/asm-x86/msr.h
@@ -192,19 +192,20 @@ do {                                                            \
 #define write_rdtscp_aux(val) wrmsr(0xc0000103, (val), 0)
 
 #ifdef CONFIG_SMP
-void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
-void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
+int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
+int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
 int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
-
 int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
 #else  /*  CONFIG_SMP  */
-static inline void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+static inline int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
 {
        rdmsr(msr_no, *l, *h);
+       return 0;
 }
-static inline void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+static inline int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
 {
        wrmsr(msr_no, l, h);
+       return 0;
 }
 static inline int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no,
                                    u32 *l, u32 *h)