From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753339AbdKVWsV (ORCPT ); Wed, 22 Nov 2017 17:48:21 -0500 Received: from omzsmtpe01.verizonbusiness.com ([199.249.25.210]:34060 "EHLO omzsmtpe01.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752456AbdKVW1h (ORCPT ); Wed, 22 Nov 2017 17:27:37 -0500 From: alexander.levin@verizon.com Cc: Ard Biesheuvel , Mark Rutland , Daniel Lezcano , alexander.levin@verizon.com X-Host: mariner.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.14 28/51] clocksource/drivers/arm_arch_timer: Validate CNTFRQ after enabling frame Thread-Topic: [PATCH AUTOSEL for 4.14 28/51] clocksource/drivers/arm_arch_timer: Validate CNTFRQ after enabling frame Thread-Index: AQHTY+DV4rCbE/P7G0+URmWEde4EWQ== Date: Wed, 22 Nov 2017 22:25:43 +0000 Message-ID: <20171122222526.20021-28-alexander.levin@verizon.com> References: <20171122222526.20021-1-alexander.levin@verizon.com> In-Reply-To: <20171122222526.20021-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vAMMmP7s030814 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 --- drivers/clocksource/arm_arch_timer.c | 38 ++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 17 deletions(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index fd4b7f684bd0..14e2419063e9 100644 --- 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 arch_timer_mem *timer_mem) 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(struct device_node *np) 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_timer_mem *timer_mem) 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_init(int platform_timer_count) 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_init(int platform_timer_count) 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; -- 2.11.0