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| author | Stephen Eta Zhou <stephen.eta.zhou@gmail.com> | 2025-12-25 16:16:31 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-02-26 15:00:46 -0800 |
| commit | 693b0b594b0f278bafa784984129c0c0f988e352 (patch) | |
| tree | 1c1cadb779429b62c102cf2a9ea14670f1f28bf6 /drivers/clocksource/timer-sp804.c | |
| parent | 65d114b5270b62aefb820ecd6c3b7caeea8f895d (diff) | |
clocksource/drivers/timer-sp804: Fix an Oops when read_current_timer is called on ARM32 platforms where the SP804 is not registered as the sched_clock.
[ Upstream commit 694921a93f3e3621e067afc545cedf6fe3b234a9 ]
On SP804, the delay timer shares the same clkevt instance with
sched_clock. On some platforms, when
sp804_clocksource_and_sched_clock_init is called with use_sched_clock
not set to 1, sched_clkevt is not properly initialized. However,
sp804_register_delay_timer is invoked unconditionally, and
read_current_timer() subsequently calls sp804_read on an uninitialized
sched_clkevt, leading to a kernel Oops when accessing
sched_clkevt->value.
Declare a dedicated clkevt instance exclusively for delay timer,
instead of sharing the same clkevt with sched_clock. This ensures
that read_current_timer continues to work correctly regardless of
whether SP804 is selected as the sched_clock.
Fixes: 640594a04f11 ("clocksource/drivers/timer-sp804: Fix read_current_timer() issue when clock source is not registered")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512250520.APOMkYRQ-lkp@intel.com/
Signed-off-by: Stephen Eta Zhou <stephen.eta.zhou@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://patch.msgid.link/20251225-fix_timersp804-v2-1-a366d7157f58@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/clocksource/timer-sp804.c')
| -rw-r--r-- | drivers/clocksource/timer-sp804.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/drivers/clocksource/timer-sp804.c b/drivers/clocksource/timer-sp804.c index e82a95ea4724..d69858427359 100644 --- a/drivers/clocksource/timer-sp804.c +++ b/drivers/clocksource/timer-sp804.c @@ -106,21 +106,25 @@ static u64 notrace sp804_read(void) return ~readl_relaxed(sched_clkevt->value); } +/* Register delay timer backed by the hardware counter */ #ifdef CONFIG_ARM static struct delay_timer delay; +static struct sp804_clkevt *delay_clkevt; + static unsigned long sp804_read_delay_timer_read(void) { - return sp804_read(); + return ~readl_relaxed(delay_clkevt->value); } -static void sp804_register_delay_timer(int freq) +static void sp804_register_delay_timer(struct sp804_clkevt *clk, int freq) { + delay_clkevt = clk; delay.freq = freq; delay.read_current_timer = sp804_read_delay_timer_read; register_current_timer_delay(&delay); } #else -static inline void sp804_register_delay_timer(int freq) {} +static inline void sp804_register_delay_timer(struct sp804_clkevt *clk, int freq) {} #endif static int __init sp804_clocksource_and_sched_clock_init(void __iomem *base, @@ -135,8 +139,6 @@ static int __init sp804_clocksource_and_sched_clock_init(void __iomem *base, if (rate < 0) return -EINVAL; - sp804_register_delay_timer(rate); - clkevt = sp804_clkevt_get(base); writel(0, clkevt->ctrl); @@ -152,6 +154,8 @@ static int __init sp804_clocksource_and_sched_clock_init(void __iomem *base, clocksource_mmio_init(clkevt->value, name, rate, 200, 32, clocksource_mmio_readl_down); + sp804_register_delay_timer(clkevt, rate); + if (use_sched_clock) { sched_clkevt = clkevt; sched_clock_register(sp804_read, 32, rate); |