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>
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index c054eaa..372ad0c 100644
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -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