From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C617C433FE for ; Fri, 7 Jan 2022 11:57:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347345AbiAGL5D (ORCPT ); Fri, 7 Jan 2022 06:57:03 -0500 Received: from foss.arm.com ([217.140.110.172]:40040 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347462AbiAGL4t (ORCPT ); Fri, 7 Jan 2022 06:56:49 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0F77F13D5; Fri, 7 Jan 2022 03:56:49 -0800 (PST) Received: from [10.57.85.117] (unknown [10.57.85.117]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C2F303F774; Fri, 7 Jan 2022 03:56:47 -0800 (PST) Message-ID: <840a1ce6-a7c5-16f6-0366-8d93a3715b34@arm.com> Date: Fri, 7 Jan 2022 11:56:46 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [PATCH V2 3/7] arm64: errata: Add detection for TRBE invalid prohibited states To: Anshuman Khandual , linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas , Will Deacon , Mathieu Poirier , coresight@lists.linaro.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org References: <1641517808-5735-1-git-send-email-anshuman.khandual@arm.com> <1641517808-5735-4-git-send-email-anshuman.khandual@arm.com> From: Suzuki K Poulose In-Reply-To: <1641517808-5735-4-git-send-email-anshuman.khandual@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/01/2022 01:10, Anshuman Khandual wrote: > TRBE implementations affected by Arm erratum #2038923 might get TRBE into > an inconsistent view on whether trace is prohibited within the CPU. As a > result, the trace buffer or trace buffer state might be corrupted. This > happens after TRBE buffer has been enabled by setting TRBLIMITR_EL1.E, > followed by just a single context synchronization event before execution > changes from a context, in which trace is prohibited to one where it isn't, > or vice versa. In these mentioned conditions, the view of whether trace is > prohibited is inconsistent between parts of the CPU, and the trace buffer > or the trace buffer state might be corrupted. This adds a new errata > ARM64_ERRATUM_2038923 in arm64 errata framework. > > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Mathieu Poirier > Cc: Suzuki Poulose > Cc: coresight@lists.linaro.org > Cc: linux-doc@vger.kernel.org > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual > --- Reviewed-by: Suzuki K Poulose > Documentation/arm64/silicon-errata.rst | 2 ++ > arch/arm64/Kconfig | 23 +++++++++++++++++++++++ > arch/arm64/kernel/cpu_errata.c | 9 +++++++++ > arch/arm64/tools/cpucaps | 1 + > 4 files changed, 35 insertions(+) > > diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst > index c9b30e6c2b6c..e0ef3e9a4b8b 100644 > --- a/Documentation/arm64/silicon-errata.rst > +++ b/Documentation/arm64/silicon-errata.rst > @@ -54,6 +54,8 @@ stable kernels. > +----------------+-----------------+-----------------+-----------------------------+ > | ARM | Cortex-A510 | #2064142 | ARM64_ERRATUM_2064142 | > +----------------+-----------------+-----------------+-----------------------------+ > +| ARM | Cortex-A510 | #2038923 | ARM64_ERRATUM_2038923 | > ++----------------+-----------------+-----------------+-----------------------------+ > | ARM | Cortex-A53 | #826319 | ARM64_ERRATUM_826319 | > +----------------+-----------------+-----------------+-----------------------------+ > | ARM | Cortex-A53 | #827319 | ARM64_ERRATUM_827319 | > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index e27ccfe9fa9c..188eae6ef28d 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -796,6 +796,29 @@ config ARM64_ERRATUM_2064142 > > If unsure, say Y. > > +config ARM64_ERRATUM_2038923 > + bool "Cortex-A510: 2038923: workaround TRBE corruption with enable" > + depends on COMPILE_TEST # Until the CoreSight TRBE driver changes are in > + default y > + help > + This option adds the workaround for ARM Cortex-A510 erratum 2038923. > + > + Affected Cortex-A510 core might cause an inconsistent view on whether trace is > + prohibited within the CPU. As a result, the trace buffer or trace buffer state > + might be corrupted. This happens after TRBE buffer has been enabled by setting > + TRBLIMITR_EL1.E, followed by just a single context synchronization event before > + execution changes from a context, in which trace is prohibited to one where it > + isn't, or vice versa. In these mentioned conditions, the view of whether trace > + is prohibited is inconsistent between parts of the CPU, and the trace buffer or > + the trace buffer state might be corrupted. > + > + Work around this in the driver by preventing an inconsistent view of whether the > + trace is prohibited or not based on TRBLIMITR_EL1.E by immediately following a > + change to TRBLIMITR_EL1.E with at least one ISB instruction before an ERET, or > + two ISB instructions if no ERET is to take place. > + > + If unsure, say Y. > + > config CAVIUM_ERRATUM_22375 > bool "Cavium erratum 22375, 24313" > default y > diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c > index cbb7d5a9aee7..60b0c1f1d912 100644 > --- a/arch/arm64/kernel/cpu_errata.c > +++ b/arch/arm64/kernel/cpu_errata.c > @@ -607,6 +607,15 @@ const struct arm64_cpu_capabilities arm64_errata[] = { > ERRATA_MIDR_REV_RANGE(MIDR_CORTEX_A510, 0, 0, 2) > }, > #endif > +#ifdef CONFIG_ARM64_ERRATUM_2038923 > + { > + .desc = "ARM erratum 2038923", > + .capability = ARM64_WORKAROUND_2038923, > + > + /* Cortex-A510 r0p0 - r0p2 */ > + ERRATA_MIDR_REV_RANGE(MIDR_CORTEX_A510, 0, 0, 2) > + }, > +#endif > { > } > }; > diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps > index fca3cb329e1d..45a06d36d080 100644 > --- a/arch/arm64/tools/cpucaps > +++ b/arch/arm64/tools/cpucaps > @@ -56,6 +56,7 @@ WORKAROUND_1463225 > WORKAROUND_1508412 > WORKAROUND_1542419 > WORKAROUND_2064142 > +WORKAROUND_2038923 > WORKAROUND_TRBE_OVERWRITE_FILL_MODE > WORKAROUND_TSB_FLUSH_FAILURE > WORKAROUND_TRBE_WRITE_OUT_OF_RANGE