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x86/tsc: Validate TSC_ADJUST after resume

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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
Download Patch File Download Diff File Expand all files Collapse all files

6
arch/x86/kernel/tsc_sync.c
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@@ -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;