From: Catalin Marinas <[email protected]>
Commit 0b46b8a718c6 got back-ported to stable, but the later fix in commit
d6ad36913083d683 didn't as it wasn't appropriately Cc'd. This has left arm64
broken in stable when booted at EL2:
BUG: failure at
./arch/arm64/include/asm/arch_timer.h:112/arch_counter_get_cntpct()!
Mark.
---->8----
Commit d6ad36913083d683aad4e02e53580c995f1a6ede upstream.
Commit 0b46b8a718c6 (clocksource: arch_timer: Fix code to use physical
timers when requested) introduces the use of physical counters in the
ARM architected timer driver. However, he arm64 kernel uses CNTVCT in
VDSO. When booting in EL2, the kernel switches to the physical timers to
make things easier for KVM but it continues to use the virtual counter
both in user and kernel. While in such scenario CNTVCT == CNTPCT (since
CNTVOFF is initialised by the kernel to 0), we want to spot firmware
bugs corrupting CNTVOFF early (which would affect CNTVCT).
Signed-off-by: Catalin Marinas <[email protected]>
Tested-by: Yingjoe Chen <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Fixes: 0b46b8a718c6 ("clocksource: arch_timer: Fix code to use physical timers
when requested")
Cc: Ian Campbell <[email protected]>
Cc: [email protected] # 3.18.x
Signed-off-by: Mark Rutland <[email protected]>
---
drivers/clocksource/arm_arch_timer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clocksource/arm_arch_timer.c
b/drivers/clocksource/arm_arch_timer.c
index 1fa2af9..84b4c8b 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -462,7 +462,7 @@ static void __init arch_counter_register(unsigned type)
/* Register the CP15 based counter if we have one */
if (type & ARCH_CP15_TIMER) {
- if (arch_timer_use_virtual)
+ if (IS_ENABLED(CONFIG_ARM64) || arch_timer_use_virtual)
arch_timer_read_counter = arch_counter_get_cntvct;
else
arch_timer_read_counter = arch_counter_get_cntpct;
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
