From 6a369583178d0b89c2c3919c4456ee22fee0f249 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 13 Dec 2016 13:14:17 +0000 Subject: [PATCH] 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/include/asm/tsc.h | 4 ++-- arch/x86/kernel/process.c | 2 +- arch/x86/kernel/tsc.c | 6 ++++++ arch/x86/kernel/tsc_sync.c | 6 +++--- arch/x86/power/cpu.c | 1 + 5 files changed, 13 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h index c054eaa7dc94..372ad0cd1357 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 diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 4fe5dc84da4f..a67e0f0cdaab 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -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(); } 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) 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; diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index 53cace2ec0e2..66ade16c7693 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -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(); -- 2.20.1