[PATCH] clocksource: arch_timer: Only use the virtual counter (CNTVCT) on arm64

[Catalin Marinas]

The 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 <catalin.marinas@xxxxxxx>
---
 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 6a79fc4f900c..095c1774592c 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;
--
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