From e09784a8a751e539dffc94d43bc917b0ac1e934a Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Tue, 11 May 2021 03:45:16 +0200 Subject: [PATCH 1/2] alarmtimer: Check RTC features instead of ops RTC drivers used to leave .set_alarm() NULL in order to signal the RTC device doesn't support alarms. The drivers are now clearing the RTC_FEATURE_ALARM bit for that purpose in order to keep the rtc_class_ops structure const. So now, .set_alarm() is set unconditionally and this possibly causes the alarmtimer code to select an RTC device that doesn't support alarms. Test RTC_FEATURE_ALARM instead of relying on ops->set_alarm to determine whether alarms are available. Fixes: 7ae41220ef58 ("rtc: introduce features bitfield") Signed-off-by: Alexandre Belloni Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210511014516.563031-1-alexandre.belloni@bootlin.com --- kernel/time/alarmtimer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index bea9d08b1698..5897828b9d7e 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -92,7 +92,7 @@ static int alarmtimer_rtc_add_device(struct device *dev, if (rtcdev) return -EBUSY; - if (!rtc->ops->set_alarm) + if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) return -1; if (!device_may_wakeup(rtc->dev.parent)) return -1; From 3486d2c9be652a31033363bdd50391b0c8a8fe21 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Thu, 13 May 2021 09:32:46 +0200 Subject: [PATCH 2/2] clocksource/drivers/hyper-v: Re-enable VDSO_CLOCKMODE_HVCLOCK on X86 Mohammed reports (https://bugzilla.kernel.org/show_bug.cgi?id=213029) the commit e4ab4658f1cf ("clocksource/drivers/hyper-v: Handle vDSO differences inline") broke vDSO on x86. The problem appears to be that VDSO_CLOCKMODE_HVCLOCK is an enum value in 'enum vdso_clock_mode' and '#ifdef VDSO_CLOCKMODE_HVCLOCK' branch evaluates to false (it is not a define). Use a dedicated HAVE_VDSO_CLOCKMODE_HVCLOCK define instead. Fixes: e4ab4658f1cf ("clocksource/drivers/hyper-v: Handle vDSO differences inline") Reported-by: Mohammed Gamal Suggested-by: Thomas Gleixner Signed-off-by: Vitaly Kuznetsov Signed-off-by: Thomas Gleixner Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20210513073246.1715070-1-vkuznets@redhat.com --- arch/x86/include/asm/vdso/clocksource.h | 2 ++ drivers/clocksource/hyperv_timer.c | 4 ++-- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/vdso/clocksource.h b/arch/x86/include/asm/vdso/clocksource.h index 119ac8612d89..136e5e57cfe1 100644 --- a/arch/x86/include/asm/vdso/clocksource.h +++ b/arch/x86/include/asm/vdso/clocksource.h @@ -7,4 +7,6 @@ VDSO_CLOCKMODE_PVCLOCK, \ VDSO_CLOCKMODE_HVCLOCK +#define HAVE_VDSO_CLOCKMODE_HVCLOCK + #endif /* __ASM_VDSO_CLOCKSOURCE_H */ diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index 977fd05ac35f..d6ece7bbce89 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -419,7 +419,7 @@ static void resume_hv_clock_tsc(struct clocksource *arg) hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr); } -#ifdef VDSO_CLOCKMODE_HVCLOCK +#ifdef HAVE_VDSO_CLOCKMODE_HVCLOCK static int hv_cs_enable(struct clocksource *cs) { vclocks_set_used(VDSO_CLOCKMODE_HVCLOCK); @@ -435,7 +435,7 @@ static struct clocksource hyperv_cs_tsc = { .flags = CLOCK_SOURCE_IS_CONTINUOUS, .suspend= suspend_hv_clock_tsc, .resume = resume_hv_clock_tsc, -#ifdef VDSO_CLOCKMODE_HVCLOCK +#ifdef HAVE_VDSO_CLOCKMODE_HVCLOCK .enable = hv_cs_enable, .vdso_clock_mode = VDSO_CLOCKMODE_HVCLOCK, #else