| Message ID | 20201119164547.2982871-3-suzuki.poulose@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | coresight: etm4x: Support for system instructions | expand |
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 >
On 11/27/20 6:55 PM, Mathieu Poirier wrote: > 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 Thanks, I will remove the "commit". Suzuki
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;
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") 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(-)