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linux-next/arch/x86/lib/msr-smp.c
Eric Dumazet 9b9a51354c x86/msr: Make rdmsrl_safe_on_cpu() scheduling safe as well
When changing rdmsr_safe_on_cpu() to schedule, it was missed that
__rdmsr_safe_on_cpu() was also used by rdmsrl_safe_on_cpu()

Make rdmsrl_safe_on_cpu() a wrapper instead of copy/pasting the code which
was added for the completion handling.

Fixes: 07cde313b2 ("x86/msr: Allow rdmsr_safe_on_cpu() to schedule")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20180328032233.153055-1-edumazet@google.com
2018-03-28 10:34:13 +02:00

281 lines
5.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/export.h>
#include <linux/preempt.h>
#include <linux/smp.h>
#include <linux/completion.h>
#include <asm/msr.h>
static void __rdmsr_on_cpu(void *info)
{
struct msr_info *rv = info;
struct msr *reg;
int this_cpu = raw_smp_processor_id();
if (rv->msrs)
reg = per_cpu_ptr(rv->msrs, this_cpu);
else
reg = &rv->reg;
rdmsr(rv->msr_no, reg->l, reg->h);
}
static void __wrmsr_on_cpu(void *info)
{
struct msr_info *rv = info;
struct msr *reg;
int this_cpu = raw_smp_processor_id();
if (rv->msrs)
reg = per_cpu_ptr(rv->msrs, this_cpu);
else
reg = &rv->reg;
wrmsr(rv->msr_no, reg->l, reg->h);
}
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 rdmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
{
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);
*q = rv.reg.q;
return err;
}
EXPORT_SYMBOL(rdmsrl_on_cpu);
int wrmsr_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;
rv.reg.l = l;
rv.reg.h = h;
err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);
return err;
}
EXPORT_SYMBOL(wrmsr_on_cpu);
int wrmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
{
int err;
struct msr_info rv;
memset(&rv, 0, sizeof(rv));
rv.msr_no = msr_no;
rv.reg.q = q;
err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);
return err;
}
EXPORT_SYMBOL(wrmsrl_on_cpu);
static void __rwmsr_on_cpus(const struct cpumask *mask, u32 msr_no,
struct msr *msrs,
void (*msr_func) (void *info))
{
struct msr_info rv;
int this_cpu;
memset(&rv, 0, sizeof(rv));
rv.msrs = msrs;
rv.msr_no = msr_no;
this_cpu = get_cpu();
if (cpumask_test_cpu(this_cpu, mask))
msr_func(&rv);
smp_call_function_many(mask, msr_func, &rv, 1);
put_cpu();
}
/* rdmsr on a bunch of CPUs
*
* @mask: which CPUs
* @msr_no: which MSR
* @msrs: array of MSR values
*
*/
void rdmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs)
{
__rwmsr_on_cpus(mask, msr_no, msrs, __rdmsr_on_cpu);
}
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 struct cpumask *mask, u32 msr_no, struct msr *msrs)
{
__rwmsr_on_cpus(mask, msr_no, msrs, __wrmsr_on_cpu);
}
EXPORT_SYMBOL(wrmsr_on_cpus);
struct msr_info_completion {
struct msr_info msr;
struct completion done;
};
/* 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_completion *rv = info;
rv->msr.err = rdmsr_safe(rv->msr.msr_no, &rv->msr.reg.l, &rv->msr.reg.h);
complete(&rv->done);
}
static void __wrmsr_safe_on_cpu(void *info)
{
struct msr_info *rv = info;
rv->err = wrmsr_safe(rv->msr_no, rv->reg.l, rv->reg.h);
}
int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
{
struct msr_info_completion rv;
call_single_data_t csd = {
.func = __rdmsr_safe_on_cpu,
.info = &rv,
};
int err;
memset(&rv, 0, sizeof(rv));
init_completion(&rv.done);
rv.msr.msr_no = msr_no;
err = smp_call_function_single_async(cpu, &csd);
if (!err) {
wait_for_completion(&rv.done);
err = rv.msr.err;
}
*l = rv.msr.reg.l;
*h = rv.msr.reg.h;
return err;
}
EXPORT_SYMBOL(rdmsr_safe_on_cpu);
int wrmsr_safe_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;
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;
}
EXPORT_SYMBOL(wrmsr_safe_on_cpu);
int wrmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
{
int err;
struct msr_info rv;
memset(&rv, 0, sizeof(rv));
rv.msr_no = msr_no;
rv.reg.q = q;
err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1);
return err ? err : rv.err;
}
EXPORT_SYMBOL(wrmsrl_safe_on_cpu);
int rdmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
{
u32 low, high;
int err;
err = rdmsr_safe_on_cpu(cpu, msr_no, &low, &high);
*q = (u64)high << 32 | low;
return err;
}
EXPORT_SYMBOL(rdmsrl_safe_on_cpu);
/*
* These variants are significantly slower, but allows control over
* the entire 32-bit GPR set.
*/
static void __rdmsr_safe_regs_on_cpu(void *info)
{
struct msr_regs_info *rv = info;
rv->err = rdmsr_safe_regs(rv->regs);
}
static void __wrmsr_safe_regs_on_cpu(void *info)
{
struct msr_regs_info *rv = info;
rv->err = wrmsr_safe_regs(rv->regs);
}
int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 *regs)
{
int err;
struct msr_regs_info rv;
rv.regs = regs;
rv.err = -EIO;
err = smp_call_function_single(cpu, __rdmsr_safe_regs_on_cpu, &rv, 1);
return err ? err : rv.err;
}
EXPORT_SYMBOL(rdmsr_safe_regs_on_cpu);
int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 *regs)
{
int err;
struct msr_regs_info rv;
rv.regs = regs;
rv.err = -EIO;
err = smp_call_function_single(cpu, __wrmsr_safe_regs_on_cpu, &rv, 1);
return err ? err : rv.err;
}
EXPORT_SYMBOL(wrmsr_safe_regs_on_cpu);