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x86: msr: propagate errors from smp_call_function_single()

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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>
This commit is contained in:
H. Peter Anvin 2008-08-25 17:27:21 -07:00
parent f73be6dedf
commit c6f31932d0
3 changed files with 28 additions and 19 deletions
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14
arch/x86/kernel/msr.c
View File

@ -79,8 +79,11 @@ static ssize_t msr_read(struct file *file, char __user *buf,
for (; count; count -= 8) { for (; count; count -= 8) {
err = rdmsr_safe_on_cpu(cpu, reg, &data[0], &data[1]); err = rdmsr_safe_on_cpu(cpu, reg, &data[0], &data[1]);
if (err) if (err) {
return -EIO; if (err == -EFAULT) /* Fix idiotic error code */
err = -EIO;
return err;
}
if (copy_to_user(tmp, &data, 8)) if (copy_to_user(tmp, &data, 8))
return -EFAULT; return -EFAULT;
tmp += 2; 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)) if (copy_from_user(&data, tmp, 8))
return -EFAULT; return -EFAULT;
err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]); err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]);
if (err) if (err) {
return -EIO; if (err == -EFAULT) /* Fix idiotic error code */
err = -EIO;
return err;
}
tmp += 2; tmp += 2;
} }

22
arch/x86/lib/msr-on-cpu.c
View File

@ -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; rv.msr_no = msr_no;
if (safe) { if (safe) {
smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1); err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu,
err = rv.err; &rv, 1);
err = err ? err : rv.err;
} else { } 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; *l = rv.l;
*h = rv.h; *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.l = l;
rv.h = h; rv.h = h;
if (safe) { if (safe) {
smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1); err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu,
err = rv.err; &rv, 1);
err = err ? err : rv.err;
} else { } else {
smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1); err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);
} }
return err; 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 /* These "safe" variants are slower and should be used when the target MSR

11
include/asm-x86/msr.h
View File

@ -192,19 +192,20 @@ do { \
#define write_rdtscp_aux(val) wrmsr(0xc0000103, (val), 0) #define write_rdtscp_aux(val) wrmsr(0xc0000103, (val), 0)
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
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);
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);
int rdmsr_safe_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); int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
#else /* CONFIG_SMP */ #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); 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); wrmsr(msr_no, l, h);
return 0;
} }
static inline int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, static inline int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no,
u32 *l, u32 *h) u32 *l, u32 *h)