This is a note to let you know that I've just added the patch titled
clocksource: arch_timer: Only use the virtual counter
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
clocksource-arch_timer-only-use-the-virtual-counter.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d6ad36913083d683aad4e02e53580c995f1a6ede Mon Sep 17 00:00:00 2001
From: Catalin Marinas <catalin.marinas@xxxxxxx>
Date: Wed, 10 Dec 2014 11:02:09 +0000
Subject: clocksource: arch_timer: Only use the virtual counter
(CNTVCT) on arm64
From: Catalin Marinas <catalin.marinas@xxxxxxx>
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 <catalin.marinas@xxxxxxx>
Tested-by: Yingjoe Chen <yingjoe.chen@xxxxxxxxxxxx>
Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Fixes: 0b46b8a718c6 ("clocksource: arch_timer: Fix code to use physical
timers when requested")
Cc: Ian Campbell <ijc@xxxxxxxxxxxxxx>
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/clocksource/arm_arch_timer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -462,7 +462,7 @@ static void __init arch_counter_register
/* 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;
Patches currently in stable-queue which might be from catalin.marinas@xxxxxxx are
queue-3.18/clocksource-arch_timer-only-use-the-virtual-counter.patch
queue-3.18/xen-arm-arm64-introduce-xen_arch_need_swiotlb.patch
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