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authorLinus Torvalds <torvalds@linux-foundation.org>2018-04-02 15:16:43 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-02 15:16:43 -0700
commit986b37c0ae4f0a3f93d8974d03a9cbc1502dd377 (patch)
tree3c92ad5c72d6410816511862bf22296e93caaa8f /arch/x86/lib
parente68b4bad71e8739d79f3c9580c719aa70c42fb96 (diff)
parent9b9a51354cae933f5640b5bb73bbcd32f989122f (diff)
Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups and msr updates from Ingo Molnar: "The main change is a performance/latency improvement to /dev/msr access. The rest are misc cleanups" * 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/msr: Make rdmsrl_safe_on_cpu() scheduling safe as well x86/cpuid: Allow cpuid_read() to schedule x86/msr: Allow rdmsr_safe_on_cpu() to schedule x86/rtc: Stop using deprecated functions x86/dumpstack: Unify show_regs() x86/fault: Do not print IP in show_fault_oops() x86/MSR: Move native_* variants to msr.h
Diffstat (limited to 'arch/x86/lib')
-rw-r--r--arch/x86/lib/msr-smp.c43
1 files changed, 28 insertions, 15 deletions
diff --git a/arch/x86/lib/msr-smp.c b/arch/x86/lib/msr-smp.c
index 693cce0be82d..fee8b9c0520c 100644
--- a/arch/x86/lib/msr-smp.c
+++ b/arch/x86/lib/msr-smp.c
@@ -2,6 +2,7 @@
#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)
@@ -143,13 +144,19 @@ void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs)
}
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 *rv = info;
+ struct msr_info_completion *rv = info;
- rv->err = rdmsr_safe(rv->msr_no, &rv->reg.l, &rv->reg.h);
+ 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)
@@ -161,17 +168,26 @@ static void __wrmsr_safe_on_cpu(void *info)
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;
- struct msr_info rv;
memset(&rv, 0, sizeof(rv));
+ init_completion(&rv.done);
+ rv.msr.msr_no = msr_no;
- rv.msr_no = msr_no;
- err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1);
- *l = rv.reg.l;
- *h = rv.reg.h;
+ 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 ? err : rv.err;
+ return err;
}
EXPORT_SYMBOL(rdmsr_safe_on_cpu);
@@ -209,16 +225,13 @@ EXPORT_SYMBOL(wrmsrl_safe_on_cpu);
int rdmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
{
+ u32 low, high;
int err;
- struct msr_info rv;
- memset(&rv, 0, sizeof(rv));
+ err = rdmsr_safe_on_cpu(cpu, msr_no, &low, &high);
+ *q = (u64)high << 32 | low;
- rv.msr_no = msr_no;
- err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1);
- *q = rv.reg.q;
-
- return err ? err : rv.err;
+ return err;
}
EXPORT_SYMBOL(rdmsrl_safe_on_cpu);