Now that Hyper-V overrides the sched_clock save/restore hooks if and only sched_clock itself is set to the Hyper-V reference counter, drop the invocation of the "old" save/restore callbacks. When the registration of the PV sched_clock was done separately from overriding the save/restore hooks, it was possible for Hyper-V to clobber the TSC save/restore callbacks without actually switching to the Hyper-V refcounter.
Enabling a PV sched_clock is a one-way street, i.e. the kernel will never revert to using TSC for sched_clock, and so there is no need to invoke the TSC save/restore hooks (and if there was, it belongs in common PV code). Reviewed-by: Michael Kelley <[email protected]> Tested-by: Michael Kelley <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> --- drivers/clocksource/hyperv_timer.c | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index 69c1c7264e5d..ac1d9f9c381c 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -527,9 +527,6 @@ static __always_inline void hv_setup_sched_clock(void *sched_clock) #include <asm/timer.h> static u64 hv_ref_counter_at_suspend; -static void (*old_save_sched_clock_state)(void); -static void (*old_restore_sched_clock_state)(void); - /* * Hyper-V clock counter resets during hibernation. Save and restore clock * offset during suspend/resume, while also considering the time passed @@ -539,8 +536,6 @@ static void (*old_restore_sched_clock_state)(void); */ static void hv_save_sched_clock_state(void) { - old_save_sched_clock_state(); - hv_ref_counter_at_suspend = hv_read_reference_counter(); } @@ -553,8 +548,6 @@ static void hv_restore_sched_clock_state(void) * - reference counter (time) now. */ hv_sched_clock_offset -= (hv_ref_counter_at_suspend - hv_read_reference_counter()); - - old_restore_sched_clock_state(); } static __always_inline void hv_setup_sched_clock(void *sched_clock) @@ -562,10 +555,7 @@ static __always_inline void hv_setup_sched_clock(void *sched_clock) /* We're on x86/x64 *and* using PV ops */ paravirt_set_sched_clock(sched_clock); - old_save_sched_clock_state = x86_platform.save_sched_clock_state; x86_platform.save_sched_clock_state = hv_save_sched_clock_state; - - old_restore_sched_clock_state = x86_platform.restore_sched_clock_state; x86_platform.restore_sched_clock_state = hv_restore_sched_clock_state; } #else /* !CONFIG_GENERIC_SCHED_CLOCK && !CONFIG_PARAVIRT */ -- 2.54.0.563.g4f69b47b94-goog
