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x86/tsc: Validate TSC_ADJUST after resume 

Some 'feature' BIOSes fiddle with the TSC_ADJUST register during
suspend/resume which renders the TSC unusable.

Add sanity checks into the resume path and restore the
original value if it was adjusted.

Reported-and-tested-by: Roland Scheidegger <rscheidegger_lists@hispeed.ch>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Bruce Schlobohm <bruce.schlobohm@intel.com>
Cc: Kevin Stanton <kevin.b.stanton@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Allen Hung <allen_hung@dell.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20161213131211.317654500@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2016-12-13 13:14:17 +00:00
parent 31f8a651fc
commit 6a36958317
5 changed files with 13 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/x86/include/asm/tsc.h
View File

@ -47,12 +47,12 @@ extern int tsc_clocksource_reliable;
*/
#ifdef CONFIG_X86_TSC
extern bool tsc_store_and_check_tsc_adjust(void);
extern void tsc_verify_tsc_adjust(void);
extern void tsc_verify_tsc_adjust(bool resume);
extern void check_tsc_sync_source(int cpu);
extern void check_tsc_sync_target(void);
#else
static inline bool tsc_store_and_check_tsc_adjust(void) { return false; }
static inline void tsc_verify_tsc_adjust(void) { }
static inline void tsc_verify_tsc_adjust(bool resume) { }
static inline void check_tsc_sync_source(int cpu) { }
static inline void check_tsc_sync_target(void) { }
#endif

2
arch/x86/kernel/process.c
View File

@ -277,7 +277,7 @@ void exit_idle(void)
void arch_cpu_idle_enter(void)
{
tsc_verify_tsc_adjust();
tsc_verify_tsc_adjust(false);
local_touch_nmi();
enter_idle();
}

6
arch/x86/kernel/tsc.c
View File

@ -1080,6 +1080,11 @@ static void detect_art(void)
static struct clocksource clocksource_tsc;
static void tsc_resume(struct clocksource *cs)
{
tsc_verify_tsc_adjust(true);
}
/*
* We used to compare the TSC to the cycle_last value in the clocksource
* structure to avoid a nasty time-warp. This can be observed in a
@ -1112,6 +1117,7 @@ static struct clocksource clocksource_tsc = {
.flags = CLOCK_SOURCE_IS_CONTINUOUS |
CLOCK_SOURCE_MUST_VERIFY,
.archdata = { .vclock_mode = VCLOCK_TSC },
.resume = tsc_resume,
};
void mark_tsc_unstable(char *reason)

6
arch/x86/kernel/tsc_sync.c
View File

@ -30,7 +30,7 @@ struct tsc_adjust {
static DEFINE_PER_CPU(struct tsc_adjust, tsc_adjust);
void tsc_verify_tsc_adjust(void)
void tsc_verify_tsc_adjust(bool resume)
{
struct tsc_adjust *adj = this_cpu_ptr(&tsc_adjust);
s64 curval;
@ -39,7 +39,7 @@ void tsc_verify_tsc_adjust(void)
return;
/* Rate limit the MSR check */
if (time_before(jiffies, adj->nextcheck))
if (!resume && time_before(jiffies, adj->nextcheck))
return;
adj->nextcheck = jiffies + HZ;
@ -51,7 +51,7 @@ void tsc_verify_tsc_adjust(void)
/* Restore the original value */
wrmsrl(MSR_IA32_TSC_ADJUST, adj->adjusted);
if (!adj->warned) {
if (!adj->warned || resume) {
pr_warn(FW_BUG "TSC ADJUST differs: CPU%u %lld --> %lld. Restoring\n",
smp_processor_id(), adj->adjusted, curval);
adj->warned = true;

1
arch/x86/power/cpu.c
View File

@ -252,6 +252,7 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
fix_processor_context();
do_fpu_end();
tsc_verify_tsc_adjust(true);
x86_platform.restore_sched_clock_state();
mtrr_bp_restore();
perf_restore_debug_store();