From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
anshuman.khandual@arm.com, catalin.marinas@arm.com,
coresight@lists.linaro.org, linux-kernel@vger.kernel.org,
jonathan.zhouwen@huawei.com,
Tingwei Zhang <tingwei@codeaurora.org>,
leo.yan@linaro.org, linux-arm-kernel@lists.infradead.org,
mike.leach@linaro.org
Subject: Re: [PATCH v7 02/28] coresight: etm4x: Skip accessing TRCPDCR in save/restore
Date: Mon, 25 Jan 2021 11:39:57 -0700 [thread overview]
Message-ID: <20210125183957.GA894394@xps15> (raw)
In-Reply-To: <20210110224850.1880240-3-suzuki.poulose@arm.com>
On Sun, Jan 10, 2021 at 10:48:24PM +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: 02510a5aa78df45 ("coresight: etm4x: Add support to skip trace unit power up")
The SHA1 should be 12 character long, something I commented on in V4. I fixed
it.
> 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>
> Reviewed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@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 76526679b998..cce65fc0c9aa 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -1373,7 +1373,8 @@ 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)) {
> @@ -1391,9 +1392,9 @@ 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;
> @@ -1488,7 +1489,8 @@ 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
>
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next prev parent reply other threads:[~2021-01-25 18:42 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-10 22:48 [PATCH v7 00/28] coresight: etm4x: Support for system instructions Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 01/28] coresight: etm4x: Handle access to TRCSSPCICRn Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 02/28] coresight: etm4x: Skip accessing TRCPDCR in save/restore Suzuki K Poulose
2021-01-25 18:39 ` Mathieu Poirier [this message]
2021-01-10 22:48 ` [PATCH v7 03/28] coresight: Introduce device access abstraction Suzuki K Poulose
2021-01-25 18:42 ` Mathieu Poirier
2021-01-10 22:48 ` [PATCH v7 04/28] coresight: tpiu: Prepare for using coresight " Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 05/28] coresight: Convert coresight_timeout to use " Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 06/28] coresight: Convert claim/disclaim operations to use access wrappers Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 07/28] coresight: etm4x: Always read the registers on the host CPU Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 08/28] coresight: etm4x: Convert all register accesses Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 09/28] coresight: etm4x: Make offset available for sysfs attributes Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 10/28] coresight: etm4x: Add commentary on the registers Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 11/28] coresight: etm4x: Add sysreg access helpers Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 12/28] coresight: etm4x: Hide sysfs attributes for unavailable registers Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 13/28] coresight: etm4x: Define DEVARCH register fields Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 14/28] coresight: etm4x: Check for Software Lock Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 15/28] coresight: etm4x: Cleanup secure exception level masks Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 16/28] coresight: etm4x: Clean up " Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 17/28] coresight: etm4x: Handle ETM architecture version Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 18/28] coresight: etm4x: Detect access early on the target CPU Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 19/28] coresight: etm4x: Use TRCDEVARCH for component discovery Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 20/28] coresight: etm4x: Expose trcdevarch via sysfs Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 21/28] coresight: etm4x: Add necessary synchronization for sysreg access Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 22/28] coresight: etm4x: Detect system instructions support Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 23/28] coresight: etm4x: Refactor probing routine Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 24/28] coresight: etm4x: Run arch feature detection on the CPU Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 25/28] coresight: etm4x: Add support for sysreg only devices Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 26/28] dts: bindings: coresight: ETM system register access only units Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 27/28] arm64: Add TRFCR_ELx definitions Suzuki K Poulose
2021-01-10 22:48 ` [PATCH v7 28/28] coresight: Add support for v8.4 SelfHosted tracing Suzuki K Poulose
2021-02-12 10:34 ` Mike Leach
2021-02-12 15:36 ` Suzuki K Poulose
2021-02-12 17:30 ` Mike Leach
2021-02-18 14:51 ` Suzuki K Poulose
2021-01-25 18:49 ` [PATCH v7 00/28] coresight: etm4x: Support for system instructions Mathieu Poirier
2021-01-25 22:05 ` Suzuki K Poulose
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