From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, mike.leach@linaro.org,
linux-kernel@vger.kernel.org, anshuman.khandual@arm.com,
jonathan.zhouwen@huawei.com, coresight@lists.linaro.org,
Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
Tingwei Zhang <tingwei@codeaurora.org>
Subject: Re: [PATCH v4 02/25] coresight: etm4x: Skip accessing TRCPDCR in save/restore
Date: Fri, 27 Nov 2020 11:55:22 -0700 [thread overview]
Message-ID: <20201127185522.GB1092947@xps15> (raw)
In-Reply-To: <20201119164547.2982871-3-suzuki.poulose@arm.com>
On Thu, Nov 19, 2020 at 04:45:24PM +0000, Suzuki K Poulose wrote:
> When the ETM is affected by Qualcomm errata, modifying the
> TRCPDCR could cause the system hang. Even though this is
> taken care of during enable/disable ETM, the ETM state
> save/restore could still access the TRCPDCR. Make sure
> we skip the access during the save/restore.
>
> Found by code inspection.
>
> Fixes: commit 02510a5aa78df45 ("coresight: etm4x: Add support to skip trace unit power up")
https://elixir.bootlin.com/linux/v5.10-rc5/source/Documentation/process/submitting-patches.rst#L121
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Mike Leach <mike.leach@linaro.org>
> Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> Cc: Tingwei Zhang <tingwei@codeaurora.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> drivers/hwtracing/coresight/coresight-etm4x-core.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index 59a4a166adf4..ea2e317ddb7d 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -1277,7 +1277,8 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
>
> state->trcclaimset = readl(drvdata->base + TRCCLAIMCLR);
>
> - state->trcpdcr = readl(drvdata->base + TRCPDCR);
> + if (!drvdata->skip_power_up)
> + state->trcpdcr = readl(drvdata->base + TRCPDCR);
>
> /* wait for TRCSTATR.IDLE to go up */
> if (coresight_timeout(drvdata->base, TRCSTATR, TRCSTATR_IDLE_BIT, 1)) {
> @@ -1295,9 +1296,9 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
> * potentially save power on systems that respect the TRCPDCR_PU
> * despite requesting software to save/restore state.
> */
> - writel_relaxed((state->trcpdcr & ~TRCPDCR_PU),
> - drvdata->base + TRCPDCR);
> -
> + if (!drvdata->skip_power_up)
> + writel_relaxed((state->trcpdcr & ~TRCPDCR_PU),
> + drvdata->base + TRCPDCR);
> out:
> CS_LOCK(drvdata->base);
> return ret;
> @@ -1392,7 +1393,8 @@ static void etm4_cpu_restore(struct etmv4_drvdata *drvdata)
>
> writel_relaxed(state->trcclaimset, drvdata->base + TRCCLAIMSET);
>
> - writel_relaxed(state->trcpdcr, drvdata->base + TRCPDCR);
> + if (!drvdata->skip_power_up)
> + writel_relaxed(state->trcpdcr, drvdata->base + TRCPDCR);
>
> drvdata->state_needs_restore = false;
>
> --
> 2.24.1
>
next prev parent reply other threads:[~2020-11-27 18:58 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-19 16:45 [PATCH v4 00/26] coresight: etm4x: Support for system instructions Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 01/25] coresight: etm4x: Handle access to TRCSSPCICRn Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 02/25] coresight: etm4x: Skip accessing TRCPDCR in save/restore Suzuki K Poulose
2020-11-20 5:40 ` Sai Prakash Ranjan
2020-11-27 18:55 ` Mathieu Poirier [this message]
2020-11-30 9:37 ` Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 03/25] coresight: Introduce device access abstraction Suzuki K Poulose
2020-11-27 19:11 ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 04/25] coresight: tpiu: Prepare for using coresight " Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 05/25] coresight: Convert coresight_timeout to use " Suzuki K Poulose
2020-11-30 20:55 ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 06/25] coresight: Convert claim/disclaim operations to use access wrappers Suzuki K Poulose
2020-11-30 21:04 ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 07/25] coresight: etm4x: Always read the registers on the host CPU Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 08/25] coresight: etm4x: Convert all register accesses Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 09/25] coresight: etm4x: Add commentary on the registers Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 10/25] coresight: etm4x: Add sysreg access helpers Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 11/25] coresight: etm4x: Define DEVARCH register fields Suzuki K Poulose
2020-11-30 21:19 ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 12/25] coresight: etm4x: Check for Software Lock Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 13/25] coresight: etm4x: Cleanup secure exception level masks Suzuki K Poulose
2020-11-30 21:25 ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 14/25] coresight: etm4x: Clean up " Suzuki K Poulose
2020-11-30 21:45 ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 15/25] coresight: etm4x: Handle ETM architecture version Suzuki K Poulose
2020-11-30 21:48 ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 16/25] coresight: etm4x: Detect access early on the target CPU Suzuki K Poulose
2020-11-30 21:53 ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 17/25] coresight: etm4x: Use TRCDEVARCH for component discovery Suzuki K Poulose
2020-11-27 18:28 ` Mathieu Poirier
2020-11-30 9:30 ` Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 18/25] coresight: etm4x: Expose trcdevarch via trcidr Suzuki K Poulose
2020-11-30 22:42 ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 19/25] coresight: etm4x: Add necessary synchronization for sysreg access Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 20/25] coresight: etm4x: Detect system instructions support Suzuki K Poulose
2020-11-23 7:58 ` Tingwei Zhang
2020-11-23 9:39 ` Suzuki K Poulose
2020-11-24 0:41 ` Tingwei Zhang
2020-11-24 11:38 ` Suzuki K Poulose
2020-11-25 4:57 ` Tingwei Zhang
2020-11-19 16:45 ` [PATCH v4 21/25] coresight: etm4x: Refactor probing routine Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 22/25] coresight: etm4x: Add support for sysreg only devices Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 23/25] dts: bindings: coresight: ETM system register access only units Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 24/25] arm64: Add TRFCR_ELx definitions Suzuki K Poulose
2020-11-19 17:18 ` Catalin Marinas
2020-11-20 10:03 ` Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 25/25] coresight: Add support for v8.4 SelfHosted tracing Suzuki K Poulose
2020-11-19 17:22 ` Catalin Marinas
2020-11-20 10:03 ` Suzuki K Poulose
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