From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Catalin Marinas , Daniel Lezcano , Arnd Bergmann , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 02/80] clocksource: arch_timer: Only use the virtual counter (CNTVCT) on arm64 Date: Thu, 19 Mar 2015 15:34:50 -0700 Message-Id: <1426804568-2907-3-git-send-email-kamal@canonical.com> In-Reply-To: <1426804568-2907-1-git-send-email-kamal@canonical.com> References: <1426804568-2907-1-git-send-email-kamal@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.13.11-ckt17 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Catalin Marinas 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 Tested-by: Yingjoe Chen Cc: Daniel Lezcano Signed-off-by: Arnd Bergmann BugLink: https://launchpad.net/bugs/1426043 Signed-off-by: Kamal Mostafa --- 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 46884f8..a40fc66 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -427,7 +427,7 @@ 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