From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53504 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751945AbdLFRZi (ORCPT ); Wed, 6 Dec 2017 12:25:38 -0500 Subject: Patch "clocksource/drivers/arm_arch_timer: Validate CNTFRQ after enabling frame" has been added to the 4.14-stable tree To: ard.biesheuvel@linaro.org, alexander.levin@verizon.com, daniel.lezcano@linaro.org, gregkh@linuxfoundation.org, mark.rutland@arm.com Cc: , From: Date: Wed, 06 Dec 2017 18:25:42 +0100 Message-ID: <151258114250169@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled clocksource/drivers/arm_arch_timer: Validate CNTFRQ after enabling frame to the 4.14-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-drivers-arm_arch_timer-validate-cntfrq-after-enabling-frame.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Wed Dec 6 18:04:41 CET 2017 From: Ard Biesheuvel Date: Mon, 16 Oct 2017 16:28:38 +0100 Subject: clocksource/drivers/arm_arch_timer: Validate CNTFRQ after enabling frame From: Ard Biesheuvel [ Upstream commit 21492e1333a0d07af6968667f128e19088cf5ead ] The ACPI GTDT code validates the CNTFRQ field of each MMIO timer frame against the CNTFRQ system register of the current CPU, to ensure that they are equal, which is mandated by the architecture. However, reading the CNTFRQ field of a frame is not possible until the RFRQ bit in the frame's CNTACRn register is set, and doing so before that willl produce the following error: arch_timer: [Firmware Bug]: CNTFRQ mismatch: frame @ 0x00000000e0be0000: (0x00000000), CPU: (0x0ee6b280) arch_timer: Disabling MMIO timers due to CNTFRQ mismatch arch_timer: Failed to initialize memory-mapped timer. The reason is that the CNTFRQ field is RES0 if access is not enabled. So move the validation of CNTFRQ into the loop that iterates over the timers to find the best frame, but defer it until after we have selected the best frame, which should also have enabled the RFRQ bit. Signed-off-by: Ard Biesheuvel Signed-off-by: Mark Rutland Signed-off-by: Daniel Lezcano Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/clocksource/arm_arch_timer.c | 38 +++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 17 deletions(-) --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -1268,10 +1268,6 @@ arch_timer_mem_find_best_frame(struct ar iounmap(cntctlbase); - if (!best_frame) - pr_err("Unable to find a suitable frame in timer @ %pa\n", - &timer_mem->cntctlbase); - return best_frame; } @@ -1372,6 +1368,8 @@ static int __init arch_timer_mem_of_init frame = arch_timer_mem_find_best_frame(timer_mem); if (!frame) { + pr_err("Unable to find a suitable frame in timer @ %pa\n", + &timer_mem->cntctlbase); ret = -EINVAL; goto out; } @@ -1420,7 +1418,7 @@ arch_timer_mem_verify_cntfrq(struct arch static int __init arch_timer_mem_acpi_init(int platform_timer_count) { struct arch_timer_mem *timers, *timer; - struct arch_timer_mem_frame *frame; + struct arch_timer_mem_frame *frame, *best_frame = NULL; int timer_count, i, ret = 0; timers = kcalloc(platform_timer_count, sizeof(*timers), @@ -1432,14 +1430,6 @@ static int __init arch_timer_mem_acpi_in if (ret || !timer_count) goto out; - for (i = 0; i < timer_count; i++) { - ret = arch_timer_mem_verify_cntfrq(&timers[i]); - if (ret) { - pr_err("Disabling MMIO timers due to CNTFRQ mismatch\n"); - goto out; - } - } - /* * While unlikely, it's theoretically possible that none of the frames * in a timer expose the combination of feature we want. @@ -1448,12 +1438,26 @@ static int __init arch_timer_mem_acpi_in timer = &timers[i]; frame = arch_timer_mem_find_best_frame(timer); - if (frame) - break; + if (!best_frame) + best_frame = frame; + + ret = arch_timer_mem_verify_cntfrq(timer); + if (ret) { + pr_err("Disabling MMIO timers due to CNTFRQ mismatch\n"); + goto out; + } + + if (!best_frame) /* implies !frame */ + /* + * Only complain about missing suitable frames if we + * haven't already found one in a previous iteration. + */ + pr_err("Unable to find a suitable frame in timer @ %pa\n", + &timer->cntctlbase); } - if (frame) - ret = arch_timer_mem_frame_register(frame); + if (best_frame) + ret = arch_timer_mem_frame_register(best_frame); out: kfree(timers); return ret; Patches currently in stable-queue which might be from ard.biesheuvel@linaro.org are queue-4.14/locking-refcounts-x86-asm-use-unique-.text-section-for-refcount-exceptions.patch queue-4.14/locking-refcounts-x86-asm-enable-config_arch_has_refcount.patch queue-4.14/clocksource-drivers-arm_arch_timer-validate-cntfrq-after-enabling-frame.patch