| Message ID | 20220803191236.3037591-1-bhupesh.sharma@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | coresight: etm4x: Fix crash observed on Qcom ETM parts with 'Low power override' | expand |
Hi Bhupesh, On 03/08/2022 20:12, Bhupesh Sharma wrote: > Some Qualcomm ETM implementations require skipping powering up > the trace unit, as the ETMs are in the same power domain as > their CPU cores. > > Via commit 5214b563588e ("coresight: etm4x: Add support for > sysreg only devices"), the setting of 'skip_power_up' flag was > moved after the 'etm4_init_arch_data' function is called, whereas > the flag value is itself used inside the function. This causes > a crash when ETM mode 'Low-power state behavior override' is set > on some Qualcomm parts. > > Fix the same. > Thanks for the patch. The patch is correct. But please see my comment below. > Fixes: 5214b563588e ("coresight: etm4x: Add support for sysreg only devices") > Cc: Mike Leach <mike.leach@linaro.org> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > Cc: Mathieu Poirier <mathieu.poirier@linaro.org> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@linaro.org> > --- > drivers/hwtracing/coresight/coresight-etm4x-core.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c > index d39660a3e50c..cf6254b87fd5 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > @@ -1943,6 +1943,16 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid) > init_arg.csa = &desc.access; > init_arg.pid = etm_pid; > > + /* > + * Some Qualcomm implementations require skipping powering up the trace unit, > + * as the ETMs are in the same power domain as their CPU cores. > + * > + * Since the 'skip_power_up' flag is used inside 'etm4_init_arch_data' function, > + * initialize it before the function is called. > + */ > + if (fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up")) > + drvdata->skip_power_up = true; > + > if (smp_call_function_single(drvdata->cpu, > etm4_init_arch_data, &init_arg, 1)) > dev_err(dev, "ETM arch init failed\n"); > @@ -1951,8 +1961,7 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid) > return -EINVAL; > > /* TRCPDCR is not accessible with system instructions. */ > - if (!desc.access.io_mem || > - fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up")) > + if (!desc.access.io_mem) > drvdata->skip_power_up = true; > Please could you move this setting into "etm4_init_sysreg_access()" ? It looks a bit odd to split the check in the same function. Moving this to the sysreg_access() makes it explicit. Suzuki > major = ETM_ARCH_MAJOR_VERSION(drvdata->arch);
Hi Suzuki, On Thu, 4 Aug 2022 at 19:02, Suzuki K Poulose <suzuki.poulose@arm.com> wrote: > > Hi Bhupesh, > > > On 03/08/2022 20:12, Bhupesh Sharma wrote: > > Some Qualcomm ETM implementations require skipping powering up > > the trace unit, as the ETMs are in the same power domain as > > their CPU cores. > > > > Via commit 5214b563588e ("coresight: etm4x: Add support for > > sysreg only devices"), the setting of 'skip_power_up' flag was > > moved after the 'etm4_init_arch_data' function is called, whereas > > the flag value is itself used inside the function. This causes > > a crash when ETM mode 'Low-power state behavior override' is set > > on some Qualcomm parts. > > > > Fix the same. > > > > Thanks for the patch. The patch is correct. But please see my comment > below. > > > Fixes: 5214b563588e ("coresight: etm4x: Add support for sysreg only devices") > > Cc: Mike Leach <mike.leach@linaro.org> > > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > > Cc: Mathieu Poirier <mathieu.poirier@linaro.org> > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@linaro.org> > > --- > > drivers/hwtracing/coresight/coresight-etm4x-core.c | 13 +++++++++++-- > > 1 file changed, 11 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c > > index d39660a3e50c..cf6254b87fd5 100644 > > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > > @@ -1943,6 +1943,16 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid) > > init_arg.csa = &desc.access; > > init_arg.pid = etm_pid; > > > > + /* > > + * Some Qualcomm implementations require skipping powering up the trace unit, > > + * as the ETMs are in the same power domain as their CPU cores. > > + * > > + * Since the 'skip_power_up' flag is used inside 'etm4_init_arch_data' function, > > + * initialize it before the function is called. > > + */ > > + if (fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up")) > > + drvdata->skip_power_up = true; > > + > > if (smp_call_function_single(drvdata->cpu, > > etm4_init_arch_data, &init_arg, 1)) > > dev_err(dev, "ETM arch init failed\n"); > > @@ -1951,8 +1961,7 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid) > > return -EINVAL; > > > > /* TRCPDCR is not accessible with system instructions. */ > > - if (!desc.access.io_mem || > > - fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up")) > > + if (!desc.access.io_mem) > > drvdata->skip_power_up = true; > > > > Please could you move this setting into "etm4_init_sysreg_access()" ? It > looks a bit odd to split the check in the same function. Moving this to > the sysreg_access() makes it explicit. Sure, let me fix this in v2. Regards, Bhupesh > > major = ETM_ARCH_MAJOR_VERSION(drvdata->arch); >
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index d39660a3e50c..cf6254b87fd5 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1943,6 +1943,16 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid) init_arg.csa = &desc.access; init_arg.pid = etm_pid; + /* + * Some Qualcomm implementations require skipping powering up the trace unit, + * as the ETMs are in the same power domain as their CPU cores. + * + * Since the 'skip_power_up' flag is used inside 'etm4_init_arch_data' function, + * initialize it before the function is called. + */ + if (fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up")) + drvdata->skip_power_up = true; + if (smp_call_function_single(drvdata->cpu, etm4_init_arch_data, &init_arg, 1)) dev_err(dev, "ETM arch init failed\n"); @@ -1951,8 +1961,7 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid) return -EINVAL; /* TRCPDCR is not accessible with system instructions. */ - if (!desc.access.io_mem || - fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up")) + if (!desc.access.io_mem) drvdata->skip_power_up = true; major = ETM_ARCH_MAJOR_VERSION(drvdata->arch);
Some Qualcomm ETM implementations require skipping powering up the trace unit, as the ETMs are in the same power domain as their CPU cores. Via commit 5214b563588e ("coresight: etm4x: Add support for sysreg only devices"), the setting of 'skip_power_up' flag was moved after the 'etm4_init_arch_data' function is called, whereas the flag value is itself used inside the function. This causes a crash when ETM mode 'Low-power state behavior override' is set on some Qualcomm parts. Fix the same. Fixes: 5214b563588e ("coresight: etm4x: Add support for sysreg only devices") Cc: Mike Leach <mike.leach@linaro.org> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Bhupesh Sharma <bhupesh.sharma@linaro.org> --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)