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authorThomas Gleixner <tglx@linutronix.de>2016-12-13 14:14:17 +0100
committerThomas Gleixner <tglx@linutronix.de>2016-12-15 11:44:29 +0100
commit6a369583178d0b89c2c3919c4456ee22fee0f249 (patch)
treeeaaebee6ac4102b724483d19a1c6f920c5406b67 /arch/x86/kernel/tsc.c
parentx86/tsc: Validate cpumask pointer before accessing it (diff)
downloadlinux-6a369583178d0b89c2c3919c4456ee22fee0f249.tar.xz
linux-6a369583178d0b89c2c3919c4456ee22fee0f249.zip
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>
Diffstat (limited to 'arch/x86/kernel/tsc.c')
-rw-r--r--arch/x86/kernel/tsc.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 2bb8de4f3b39..bfb541a5bb48 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -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)