| Message ID | 20220825052232.11013-1-bhupesh.sharma@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] coresight: etm4x: Fix crash observed on Qcom ETM parts with 'Low power override' | expand |
On 8/25/22 10:52 AM, 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. > > 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> > --- > - v1 can be seen here: https://lore.kernel.org/lkml/20220803191236.3037591-1-bhupesh.sharma@linaro.org/ > - Addressed the review comments from Suzuki. > - Rebased on linux-next. > > 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..14c1c7869795 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > @@ -977,6 +977,16 @@ static bool etm4_init_sysreg_access(struct etmv4_drvdata *drvdata, > if (!cpu_supports_sysreg_trace()) > return false; > > + /* > + * 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; > + > /* > * ETMs implementing sysreg access must implement TRCDEVARCH. > */ > @@ -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); Gentle ping. Any review comments on the v2? Thanks, Bhupesh
Hi Bhupesh, On Thu, Aug 25, 2022 at 10:52:32AM +0530, 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. > > 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> > --- > - v1 can be seen here: https://lore.kernel.org/lkml/20220803191236.3037591-1-bhupesh.sharma@linaro.org/ > - Addressed the review comments from Suzuki. > - Rebased on linux-next. > > 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..14c1c7869795 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > @@ -977,6 +977,16 @@ static bool etm4_init_sysreg_access(struct etmv4_drvdata *drvdata, > if (!cpu_supports_sysreg_trace()) > return false; > > + /* > + * 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; > + I personally think this sentence should be placed in the function etm4_probe(), you need to move it just before smp call etm4_init_arch_data(), this can allow DT property "qcom,skip-power-up" to be respected. > /* > * ETMs implementing sysreg access must implement TRCDEVARCH. > */ > @@ -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; I prefer to move the condition checking for "desc.access.io_mem" to etm4_init_sysreg_access(), this can make sure the flag skip_power_up is set correctly based on property of system register access. A side topic, in the mainline kernel I found the value "desc.access.io_mem" is always zero (see the initialized value in etm4_probe() and etm4_init_sysreg_access()). Should we initialize desc.access.io_mem to true in etm4_probe()? diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index d39660a3e50c..cf2555c50abb 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1939,6 +1939,7 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid) if (drvdata->cpu < 0) return drvdata->cpu; + desc.access.io_mem = true; init_arg.drvdata = drvdata; init_arg.csa = &desc.access; init_arg.pid = etm_pid; Thanks, Leo > major = ETM_ARCH_MAJOR_VERSION(drvdata->arch); > -- > 2.35.3 >
On 13/09/2022 11:52, Leo Yan wrote: > Hi Bhupesh, > > On Thu, Aug 25, 2022 at 10:52:32AM +0530, 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. >> >> 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> >> --- >> - v1 can be seen here: https://lore.kernel.org/lkml/20220803191236.3037591-1-bhupesh.sharma@linaro.org/ >> - Addressed the review comments from Suzuki. >> - Rebased on linux-next. >> >> 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..14c1c7869795 100644 >> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c >> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c >> @@ -977,6 +977,16 @@ static bool etm4_init_sysreg_access(struct etmv4_drvdata *drvdata, >> if (!cpu_supports_sysreg_trace()) >> return false; >> >> + /* >> + * 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; >> + > > I personally think this sentence should be placed in the function > etm4_probe(), you need to move it just before smp call > etm4_init_arch_data(), this can allow DT property "qcom,skip-power-up" > to be respected. Or we could move this to init_iomem_access() and explicitly set the flag to true in init_sysreg_access(). > >> /* >> * ETMs implementing sysreg access must implement TRCDEVARCH. >> */ >> @@ -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; > > I prefer to move the condition checking for "desc.access.io_mem" to > etm4_init_sysreg_access(), this can make sure the flag skip_power_up > is set correctly based on property of system register access. +1 > > A side topic, in the mainline kernel I found the value > "desc.access.io_mem" is always zero (see the initialized value in > etm4_probe() and etm4_init_sysreg_access()). Should we initialize > desc.access.io_mem to true in etm4_probe()? Thats not true. It is initialised at : etm4_init_iomem_access(): *csa = CSDEV_ACCESS_IOMEM(drvdata->base); Where #define CSDEV_ACCESS_IOMEM(_addr) \ ((struct csdev_access) { \ .io_mem = true, \ .base = (_addr), \ }) Suzuki
On Wed, Sep 14, 2022 at 03:43:53PM +0100, Suzuki Kuruppassery Poulose wrote: [...] > > > + /* > > > + * 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; > > > + > > > > I personally think this sentence should be placed in the function > > etm4_probe(), you need to move it just before smp call > > etm4_init_arch_data(), this can allow DT property "qcom,skip-power-up" > > to be respected. > > Or we could move this to init_iomem_access() and explicitly set the flag > to true in init_sysreg_access(). Agreed, this is more clear. [...] > > A side topic, in the mainline kernel I found the value > > "desc.access.io_mem" is always zero (see the initialized value in > > etm4_probe() and etm4_init_sysreg_access()). Should we initialize > > desc.access.io_mem to true in etm4_probe()? > > Thats not true. It is initialised at : > > etm4_init_iomem_access(): > > *csa = CSDEV_ACCESS_IOMEM(drvdata->base); > > Where > > #define CSDEV_ACCESS_IOMEM(_addr) \ > ((struct csdev_access) { \ > .io_mem = true, \ > .base = (_addr), \ > }) Thanks a lot for explaination, sorry for noise. Leo
Hi Bupesh, \ On 14/09/2022 15:43, Suzuki K Poulose wrote: > On 13/09/2022 11:52, Leo Yan wrote: >> Hi Bhupesh, >> >> On Thu, Aug 25, 2022 at 10:52:32AM +0530, 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. >>> >>> 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> >>> --- >>> - v1 can be seen here: >>> https://lore.kernel.org/lkml/20220803191236.3037591-1-bhupesh.sharma@linaro.org/ >>> - Addressed the review comments from Suzuki. >>> - Rebased on linux-next. >>> >>> 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..14c1c7869795 100644 >>> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c >>> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c >>> @@ -977,6 +977,16 @@ static bool etm4_init_sysreg_access(struct >>> etmv4_drvdata *drvdata, >>> if (!cpu_supports_sysreg_trace()) >>> return false; >>> + /* >>> + * 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; >>> + >> >> I personally think this sentence should be placed in the function >> etm4_probe(), you need to move it just before smp call >> etm4_init_arch_data(), this can allow DT property "qcom,skip-power-up" >> to be respected. > > Or we could move this to init_iomem_access() and explicitly set the flag > to true in init_sysreg_access(). > >> >>> /* >>> * ETMs implementing sysreg access must implement TRCDEVARCH. >>> */ >>> @@ -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; >> >> I prefer to move the condition checking for "desc.access.io_mem" to >> etm4_init_sysreg_access(), this can make sure the flag skip_power_up >> is set correctly based on property of system register access. > > +1 > Do you plan to send an updated patch for this one ? Kind regards Suzuki
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index d39660a3e50c..14c1c7869795 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -977,6 +977,16 @@ static bool etm4_init_sysreg_access(struct etmv4_drvdata *drvdata, if (!cpu_supports_sysreg_trace()) return false; + /* + * 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; + /* * ETMs implementing sysreg access must implement TRCDEVARCH. */ @@ -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> --- - v1 can be seen here: https://lore.kernel.org/lkml/20220803191236.3037591-1-bhupesh.sharma@linaro.org/ - Addressed the review comments from Suzuki. - Rebased on linux-next. drivers/hwtracing/coresight/coresight-etm4x-core.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)