From patchwork Thu Jan 19 11:46:45 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ding Tianhong X-Patchwork-Id: 9525595 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 840A260437 for ; Thu, 19 Jan 2017 11:52:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 723272849E for ; Thu, 19 Jan 2017 11:52:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6694528500; Thu, 19 Jan 2017 11:52:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=2.0 tests=BAYES_00,RDNS_NONE autolearn=no version=3.3.1 Received: from bombadil.infradead.org (unknown [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id CD5852849E for ; Thu, 19 Jan 2017 11:52:26 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cUBGS-00021f-TS; Thu, 19 Jan 2017 11:52:24 +0000 Received: from szxga03-in.huawei.com ([119.145.14.66]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cUBGN-0001uG-0m for linux-arm-kernel@lists.infradead.org; Thu, 19 Jan 2017 11:52:22 +0000 Received: from 172.24.1.136 (EHLO SZXEML423-HUB.china.huawei.com) ([172.24.1.136]) by szxrg03-dlp.huawei.com (MOS 4.4.3-GA FastPath queued) with ESMTP id COG42282; Thu, 19 Jan 2017 19:47:12 +0800 (CST) Received: from localhost (10.177.23.32) by SZXEML423-HUB.china.huawei.com (10.82.67.154) with Microsoft SMTP Server id 14.3.235.1; Thu, 19 Jan 2017 19:47:04 +0800 From: Ding Tianhong To: , , , , , , , , , Subject: [PATCH RESEND v8 3/4] arm64: arch_timer: Work around Erratum Hisilicon-161010101 Date: Thu, 19 Jan 2017 19:46:45 +0800 Message-ID: <1484826406-16348-4-git-send-email-dingtianhong@huawei.com> X-Mailer: git-send-email 1.8.5.2.msysgit.0 In-Reply-To: <1484826406-16348-1-git-send-email-dingtianhong@huawei.com> References: <1484826406-16348-1-git-send-email-dingtianhong@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.177.23.32] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170119_035220_198456_6BC24CE3 X-CRM114-Status: GOOD ( 16.90 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ding Tianhong Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Erratum Hisilicon-161010101 says that the ARM generic timer counter "has the potential to contain an erroneous value when the timer value changes". Accesses to TVAL (both read and write) are also affected due to the implicit counter read. Accesses to CVAL are not affected. The workaround is to reread the system count registers until the value of the second read is larger than the first one by less than 32, the system counter can be guaranteed not to return wrong value twice by back-to-back read and the error value is always larger than the correct one by 32. Writes to TVAL are replaced with an equivalent write to CVAL. The hisilicon erratum CONFIG name is too long, breaking the line format in silicon-errata.txt, so extended the character spacing to fit all the erratum config. Signed-off-by: Ding Tianhong --- Documentation/arm64/silicon-errata.txt | 43 ++++++++++++++--------------- drivers/clocksource/Kconfig | 12 ++++++++- drivers/clocksource/arm_arch_timer.c | 49 ++++++++++++++++++++++++++++++++++ 3 files changed, 82 insertions(+), 22 deletions(-) diff --git a/Documentation/arm64/silicon-errata.txt b/Documentation/arm64/silicon-errata.txt index 405da11..0aaae35 100644 --- a/Documentation/arm64/silicon-errata.txt +++ b/Documentation/arm64/silicon-errata.txt @@ -42,24 +42,25 @@ file acts as a registry of software workarounds in the Linux Kernel and will be updated when new workarounds are committed and backported to stable kernels. -| Implementor | Component | Erratum ID | Kconfig | -+----------------+-----------------+-----------------+-------------------------+ -| ARM | Cortex-A53 | #826319 | ARM64_ERRATUM_826319 | -| ARM | Cortex-A53 | #827319 | ARM64_ERRATUM_827319 | -| ARM | Cortex-A53 | #824069 | ARM64_ERRATUM_824069 | -| ARM | Cortex-A53 | #819472 | ARM64_ERRATUM_819472 | -| ARM | Cortex-A53 | #845719 | ARM64_ERRATUM_845719 | -| ARM | Cortex-A53 | #843419 | ARM64_ERRATUM_843419 | -| ARM | Cortex-A57 | #832075 | ARM64_ERRATUM_832075 | -| ARM | Cortex-A57 | #852523 | N/A | -| ARM | Cortex-A57 | #834220 | ARM64_ERRATUM_834220 | -| ARM | Cortex-A72 | #853709 | N/A | -| ARM | MMU-500 | #841119,#826419 | N/A | -| | | | | -| Cavium | ThunderX ITS | #22375, #24313 | CAVIUM_ERRATUM_22375 | -| Cavium | ThunderX ITS | #23144 | CAVIUM_ERRATUM_23144 | -| Cavium | ThunderX GICv3 | #23154 | CAVIUM_ERRATUM_23154 | -| Cavium | ThunderX Core | #27456 | CAVIUM_ERRATUM_27456 | -| Cavium | ThunderX SMMUv2 | #27704 | N/A | -| | | | | -| Freescale/NXP | LS2080A/LS1043A | A-008585 | FSL_ERRATUM_A008585 | +| Implementor | Component | Erratum ID | Kconfig | ++----------------+-----------------+-----------------+---------------------------------+ +| ARM | Cortex-A53 | #826319 | ARM64_ERRATUM_826319 | +| ARM | Cortex-A53 | #827319 | ARM64_ERRATUM_827319 | +| ARM | Cortex-A53 | #824069 | ARM64_ERRATUM_824069 | +| ARM | Cortex-A53 | #819472 | ARM64_ERRATUM_819472 | +| ARM | Cortex-A53 | #845719 | ARM64_ERRATUM_845719 | +| ARM | Cortex-A53 | #843419 | ARM64_ERRATUM_843419 | +| ARM | Cortex-A57 | #832075 | ARM64_ERRATUM_832075 | +| ARM | Cortex-A57 | #852523 | N/A | +| ARM | Cortex-A57 | #834220 | ARM64_ERRATUM_834220 | +| ARM | Cortex-A72 | #853709 | N/A | +| ARM | MMU-500 | #841119,#826419 | N/A | +| | | | | +| Cavium | ThunderX ITS | #22375, #24313 | CAVIUM_ERRATUM_22375 | +| Cavium | ThunderX ITS | #23144 | CAVIUM_ERRATUM_23144 | +| Cavium | ThunderX GICv3 | #23154 | CAVIUM_ERRATUM_23154 | +| Cavium | ThunderX Core | #27456 | CAVIUM_ERRATUM_27456 | +| Cavium | ThunderX SMMUv2 | #27704 | N/A | +| | | | | +| Freescale/NXP | LS2080A/LS1043A | A-008585 | FSL_ERRATUM_A008585 | +| Hisilicon | Hip0{5,6,7} | #161010101 | HISILICON_ERRATUM_161010101 | diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 04c2b93..628cb44 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -327,7 +327,7 @@ config ARM_ARCH_TIMER_EVTSTREAM config ARM_ARCH_TIMER_OOL_WORKAROUND bool "Workaround for arm arch timer unstable counter" - depends on FSL_ERRATUM_A008585 + depends on FSL_ERRATUM_A008585 || HISILICON_ERRATUM_161010101 help This option would only be enabled by Freescale/NXP Erratum A-008585 or something else chip has similar erratum. @@ -343,6 +343,16 @@ config FSL_ERRATUM_A008585 value"). The workaround will only be active if the fsl,erratum-a008585 property is found in the timer node. +config HISILICON_ERRATUM_161010101 + bool "Workaround for Hisilicon Erratum 161010101" + default y + select ARM_ARCH_TIMER_OOL_WORKAROUND + depends on ARM_ARCH_TIMER && ARM64 + help + This option enables a workaround for Hisilicon Erratum + 161010101. The workaround will be active if the hisilicon,erratum-161010101 + property is found in the timer node. + config ARM_GLOBAL_TIMER bool "Support for the ARM global timer" if COMPILE_TEST select CLKSRC_OF if OF diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 2487c66..7451b62 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -131,6 +131,47 @@ static u64 notrace fsl_a008585_read_cntvct_el0(void) } #endif +#ifdef CONFIG_HISILICON_ERRATUM_161010101 +/* + * Verify whether the value of the second read is larger than the first by + * less than 32 is the only way to confirm the value is correct, so clear the + * lower 5 bits to check whether the difference is greater than 32 or not. + * Theoretically the erratum should not occur more than twice in succession + * when reading the system counter, but it is possible that some interrupts + * may lead to more than twice read errors, triggering the warning, so setting + * the number of retries far beyond the number of iterations the loop has been + * observed to take. + */ +#define __hisi_161010101_read_reg(reg) ({ \ + u64 _old, _new; \ + int _retries = 50; \ + \ + do { \ + _old = read_sysreg(reg); \ + _new = read_sysreg(reg); \ + _retries--; \ + } while (unlikely((_new - _old) >> 5) && _retries); \ + \ + WARN_ON_ONCE(!_retries); \ + _new; \ +}) + +static u32 notrace hisi_161010101_read_cntp_tval_el0(void) +{ + return __hisi_161010101_read_reg(cntp_tval_el0); +} + +static u32 notrace hisi_161010101_read_cntv_tval_el0(void) +{ + return __hisi_161010101_read_reg(cntv_tval_el0); +} + +static u64 notrace hisi_161010101_read_cntvct_el0(void) +{ + return __hisi_161010101_read_reg(cntvct_el0); +} +#endif + #ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround = NULL; EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround); @@ -147,6 +188,14 @@ static u64 notrace fsl_a008585_read_cntvct_el0(void) .read_cntvct_el0 = fsl_a008585_read_cntvct_el0, }, #endif +#ifdef CONFIG_HISILICON_ERRATUM_161010101 + { + .id = "hisilicon,erratum-161010101", + .read_cntp_tval_el0 = hisi_161010101_read_cntp_tval_el0, + .read_cntv_tval_el0 = hisi_161010101_read_cntv_tval_el0, + .read_cntvct_el0 = hisi_161010101_read_cntvct_el0, + }, +#endif }; #endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */