All VDSO clock sources are TSC based and use CLOCKSOURCE_MASK(64). There is no point in masking with all FF. Get rid of it and enforce the mask in the sanity checker. Signed-off-by: Thomas Gleixner --- arch/x86/entry/vdso/vclock_gettime.c | 2 +- arch/x86/kernel/time.c | 6 ++++++ 2 files changed, 7 insertions(+), 1 deletion(-) --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -199,7 +199,7 @@ notrace static inline u64 vgetsns(int *m #endif else return 0; - v = (cycles - gtod->cycle_last) & gtod->mask; + v = cycles - gtod->cycle_last; return v * gtod->mult; } --- a/arch/x86/kernel/time.c +++ b/arch/x86/kernel/time.c @@ -120,4 +120,10 @@ void clocksource_arch_init(struct clocks cs->name, cs->archdata.vclock_mode); cs->archdata.vclock_mode = VCLOCK_NONE; } + + if (cs->mask != CLOCKSOURCE_MASK(64)) { + pr_warn("clocksource %s registered with invalid mask %016llx. Disabling vclock.\n", + cs->name, cs->mask); + cs->archdata.vclock_mode = VCLOCK_NONE; + } }