From mboxrd@z Thu Jan 1 00:00:00 1970 From: dianders@chromium.org (Doug Anderson) Date: Wed, 4 Jun 2014 10:30:32 -0700 Subject: [PATCH 1/3] clocksource: exynos_mct: Fix ftrace Message-ID: <1401903034-20074-1-git-send-email-dianders@chromium.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org In (93bfb76 clocksource: exynos_mct: register sched_clock callback) we supported using the MCT as a scheduler clock. We properly marked exynos4_read_sched_clock() as notrace. However, we then went and called another function that _wasn't_ notrace. That means if you do: cd /sys/kernel/debug/tracing/ echo function_graph > current_tracer You'll get a crash. Fix this (but still let other readers of the MCT be trace-enabled) by adding an extra function. It's important to keep other users of MCT traceable because the MCT is actually quite slow. Signed-off-by: Doug Anderson --- drivers/clocksource/exynos_mct.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c index 8d64200..ba3a683 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -165,7 +165,7 @@ static void exynos4_mct_frc_start(u32 hi, u32 lo) exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON); } -static cycle_t exynos4_frc_read(struct clocksource *cs) +static inline cycle_t notrace _exynos4_frc_read(void) { unsigned int lo, hi; u32 hi2 = __raw_readl(reg_base + EXYNOS4_MCT_G_CNT_U); @@ -179,6 +179,11 @@ static cycle_t exynos4_frc_read(struct clocksource *cs) return ((cycle_t)hi << 32) | lo; } +static cycle_t exynos4_frc_read(struct clocksource *cs) +{ + return _exynos4_frc_read(); +} + static void exynos4_frc_resume(struct clocksource *cs) { exynos4_mct_frc_start(0, 0); @@ -195,7 +200,7 @@ struct clocksource mct_frc = { static u64 notrace exynos4_read_sched_clock(void) { - return exynos4_frc_read(&mct_frc); + return _exynos4_frc_read(); } static void __init exynos4_clocksource_init(void) -- 2.0.0.526.g5318336