From 6a369583178d0b89c2c3919c4456ee22fee0f249 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 13 Dec 2016 13:14:17 +0000 Subject: 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 Signed-off-by: Thomas Gleixner Cc: Bruce Schlobohm Cc: Kevin Stanton Cc: Peter Zijlstra Cc: Allen Hung Cc: Borislav Petkov Link: http://lkml.kernel.org/r/20161213131211.317654500@linutronix.de Signed-off-by: Thomas Gleixner --- arch/x86/kernel/tsc_sync.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/x86/kernel/tsc_sync.c') diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c index a75f696011d5..94f2ce5fb159 100644 --- a/arch/x86/kernel/tsc_sync.c +++ b/arch/x86/kernel/tsc_sync.c @@ -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; -- cgit