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Commit c6f31932 authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

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: default avatarH. Peter Anvin <hpa@zytor.com>
parent f73be6de
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+10 −4
Original line number Diff line number Diff line
@@ -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;
	}

+12 −10
Original line number Diff line number Diff line
@@ -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
+6 −5
Original line number Diff line number Diff line
@@ -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)