| Message ID | 1436258518-9339-3-git-send-email-zhang.chunyan@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 07/07/2015 04:41 AM, Chunyan Zhang wrote: > 'ctxid_val' array was used to store the value of ETM context ID comparator > which actually stores the process ID to be traced, so using 'ctxid_pid' as > its name instead make it easier to understand. Previous discussion with some ARM folks has led me to believe there isn't a guarantee that the Context ID Register will always have a PID. Why not allow filtering on thread group ID, session ID, cgroup related identifiers, etc.? > This patch also changes the ABI, it is normally not allowed, but > fortunately it is a testing ABI and very new for now. Nevertheless, > if you don't think it should be changed, we could always add an alias > for userspace. > > Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org> > Reviewed-by: Mark Brown <broonie@kernel.org> > --- > .../ABI/testing/sysfs-bus-coresight-devices-etm4x | 2 +- > drivers/hwtracing/coresight/coresight-etm4x.c | 20 ++++++++++---------- > drivers/hwtracing/coresight/coresight-etm4x.h | 4 ++-- > 3 files changed, 13 insertions(+), 13 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x > index 2fe2e3d..2355ed8 100644 > --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x > +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x > @@ -249,7 +249,7 @@ KernelVersion: 4.01 > Contact: Mathieu Poirier <mathieu.poirier@linaro.org> > Description: (RW) Select which context ID comparator to work with. > > -What: /sys/bus/coresight/devices/<memory_map>.etm/ctxid_val > +What: /sys/bus/coresight/devices/<memory_map>.etm/ctxid_pid > Date: April 2015 > KernelVersion: 4.01 > Contact: Mathieu Poirier <mathieu.poirier@linaro.org> > diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c > index 1312e99..9afbda5 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x.c > @@ -155,7 +155,7 @@ static void etm4_enable_hw(void *info) > drvdata->base + TRCACATRn(i)); > } > for (i = 0; i < drvdata->numcidc; i++) > - writeq_relaxed(drvdata->ctxid_val[i], > + writeq_relaxed(drvdata->ctxid_pid[i], > drvdata->base + TRCCIDCVRn(i)); > writel_relaxed(drvdata->ctxid_mask0, drvdata->base + TRCCIDCCTLR0); > writel_relaxed(drvdata->ctxid_mask1, drvdata->base + TRCCIDCCTLR1); > @@ -507,7 +507,7 @@ static ssize_t reset_store(struct device *dev, > > drvdata->ctxid_idx = 0x0; > for (i = 0; i < drvdata->numcidc; i++) > - drvdata->ctxid_val[i] = 0x0; > + drvdata->ctxid_pid[i] = 0x0; > drvdata->ctxid_mask0 = 0x0; > drvdata->ctxid_mask1 = 0x0; > > @@ -1815,7 +1815,7 @@ static ssize_t ctxid_idx_store(struct device *dev, > } > static DEVICE_ATTR_RW(ctxid_idx); > > -static ssize_t ctxid_val_show(struct device *dev, > +static ssize_t ctxid_pid_show(struct device *dev, > struct device_attribute *attr, > char *buf) > { > @@ -1825,12 +1825,12 @@ static ssize_t ctxid_val_show(struct device *dev, > > spin_lock(&drvdata->spinlock); > idx = drvdata->ctxid_idx; > - val = (unsigned long)drvdata->ctxid_val[idx]; > + val = (unsigned long)drvdata->ctxid_pid[idx]; > spin_unlock(&drvdata->spinlock); > return scnprintf(buf, PAGE_SIZE, "%#lx\n", val); > } > > -static ssize_t ctxid_val_store(struct device *dev, > +static ssize_t ctxid_pid_store(struct device *dev, > struct device_attribute *attr, > const char *buf, size_t size) > { > @@ -1850,11 +1850,11 @@ static ssize_t ctxid_val_store(struct device *dev, > > spin_lock(&drvdata->spinlock); > idx = drvdata->ctxid_idx; > - drvdata->ctxid_val[idx] = (u64)val; > + drvdata->ctxid_pid[idx] = (u64)val; > spin_unlock(&drvdata->spinlock); > return size; > } > -static DEVICE_ATTR_RW(ctxid_val); > +static DEVICE_ATTR_RW(ctxid_pid); > > static ssize_t ctxid_masks_show(struct device *dev, > struct device_attribute *attr, > @@ -1949,7 +1949,7 @@ static ssize_t ctxid_masks_store(struct device *dev, > */ > for (j = 0; j < 8; j++) { > if (maskbyte & 1) > - drvdata->ctxid_val[i] &= ~(0xFF << (j * 8)); > + drvdata->ctxid_pid[i] &= ~(0xFF << (j * 8)); > maskbyte >>= 1; > } > /* Select the next ctxid comparator mask value */ > @@ -2193,7 +2193,7 @@ static struct attribute *coresight_etmv4_attrs[] = { > &dev_attr_res_idx.attr, > &dev_attr_res_ctrl.attr, > &dev_attr_ctxid_idx.attr, > - &dev_attr_ctxid_val.attr, > + &dev_attr_ctxid_pid.attr, > &dev_attr_ctxid_masks.attr, > &dev_attr_vmid_idx.attr, > &dev_attr_vmid_val.attr, > @@ -2514,7 +2514,7 @@ static void etm4_init_default_data(struct etmv4_drvdata *drvdata) > } > > for (i = 0; i < drvdata->numcidc; i++) > - drvdata->ctxid_val[i] = 0x0; > + drvdata->ctxid_pid[i] = 0x0; > drvdata->ctxid_mask0 = 0x0; > drvdata->ctxid_mask1 = 0x0; > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h > index e08e983..1e8fb36 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x.h > +++ b/drivers/hwtracing/coresight/coresight-etm4x.h > @@ -265,7 +265,7 @@ > * @addr_type: Current status of the comparator register. > * @ctxid_idx: Context ID index selector. > * @ctxid_size: Size of the context ID field to consider. > - * @ctxid_val: Value of the context ID comparator. > + * @ctxid_pid: Value of the context ID comparator. > * @ctxid_mask0:Context ID comparator mask for comparator 0-3. > * @ctxid_mask1:Context ID comparator mask for comparator 4-7. > * @vmid_idx: VM ID index selector. > @@ -352,7 +352,7 @@ struct etmv4_drvdata { > u8 addr_type[ETM_MAX_SINGLE_ADDR_CMP]; > u8 ctxid_idx; > u8 ctxid_size; > - u64 ctxid_val[ETMv4_MAX_CTXID_CMP]; > + u64 ctxid_pid[ETMv4_MAX_CTXID_CMP]; > u32 ctxid_mask0; > u32 ctxid_mask1; > u8 vmid_idx; >
On 26 August 2015 at 11:57, Christopher Covington <cov@codeaurora.org> wrote: > On 07/07/2015 04:41 AM, Chunyan Zhang wrote: >> 'ctxid_val' array was used to store the value of ETM context ID comparator >> which actually stores the process ID to be traced, so using 'ctxid_pid' as >> its name instead make it easier to understand. > > Previous discussion with some ARM folks has led me to believe there isn't a > guarantee that the Context ID Register will always have a PID. Why not allow > filtering on thread group ID, session ID, cgroup related identifiers, etc.? Coresight tracers only support contextID tracing. The HW automatically does the match between the contextID comparator register in the tracer with the contextID register of the core. Tracing is enabled if both values match (and the tracer is configured to do so). > >> This patch also changes the ABI, it is normally not allowed, but >> fortunately it is a testing ABI and very new for now. Nevertheless, >> if you don't think it should be changed, we could always add an alias >> for userspace. >> >> Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org> >> Reviewed-by: Mark Brown <broonie@kernel.org> >> --- >> .../ABI/testing/sysfs-bus-coresight-devices-etm4x | 2 +- >> drivers/hwtracing/coresight/coresight-etm4x.c | 20 ++++++++++---------- >> drivers/hwtracing/coresight/coresight-etm4x.h | 4 ++-- >> 3 files changed, 13 insertions(+), 13 deletions(-) >> >> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x >> index 2fe2e3d..2355ed8 100644 >> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x >> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x >> @@ -249,7 +249,7 @@ KernelVersion: 4.01 >> Contact: Mathieu Poirier <mathieu.poirier@linaro.org> >> Description: (RW) Select which context ID comparator to work with. >> >> -What: /sys/bus/coresight/devices/<memory_map>.etm/ctxid_val >> +What: /sys/bus/coresight/devices/<memory_map>.etm/ctxid_pid >> Date: April 2015 >> KernelVersion: 4.01 >> Contact: Mathieu Poirier <mathieu.poirier@linaro.org> >> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c >> index 1312e99..9afbda5 100644 >> --- a/drivers/hwtracing/coresight/coresight-etm4x.c >> +++ b/drivers/hwtracing/coresight/coresight-etm4x.c >> @@ -155,7 +155,7 @@ static void etm4_enable_hw(void *info) >> drvdata->base + TRCACATRn(i)); >> } >> for (i = 0; i < drvdata->numcidc; i++) >> - writeq_relaxed(drvdata->ctxid_val[i], >> + writeq_relaxed(drvdata->ctxid_pid[i], >> drvdata->base + TRCCIDCVRn(i)); >> writel_relaxed(drvdata->ctxid_mask0, drvdata->base + TRCCIDCCTLR0); >> writel_relaxed(drvdata->ctxid_mask1, drvdata->base + TRCCIDCCTLR1); >> @@ -507,7 +507,7 @@ static ssize_t reset_store(struct device *dev, >> >> drvdata->ctxid_idx = 0x0; >> for (i = 0; i < drvdata->numcidc; i++) >> - drvdata->ctxid_val[i] = 0x0; >> + drvdata->ctxid_pid[i] = 0x0; >> drvdata->ctxid_mask0 = 0x0; >> drvdata->ctxid_mask1 = 0x0; >> >> @@ -1815,7 +1815,7 @@ static ssize_t ctxid_idx_store(struct device *dev, >> } >> static DEVICE_ATTR_RW(ctxid_idx); >> >> -static ssize_t ctxid_val_show(struct device *dev, >> +static ssize_t ctxid_pid_show(struct device *dev, >> struct device_attribute *attr, >> char *buf) >> { >> @@ -1825,12 +1825,12 @@ static ssize_t ctxid_val_show(struct device *dev, >> >> spin_lock(&drvdata->spinlock); >> idx = drvdata->ctxid_idx; >> - val = (unsigned long)drvdata->ctxid_val[idx]; >> + val = (unsigned long)drvdata->ctxid_pid[idx]; >> spin_unlock(&drvdata->spinlock); >> return scnprintf(buf, PAGE_SIZE, "%#lx\n", val); >> } >> >> -static ssize_t ctxid_val_store(struct device *dev, >> +static ssize_t ctxid_pid_store(struct device *dev, >> struct device_attribute *attr, >> const char *buf, size_t size) >> { >> @@ -1850,11 +1850,11 @@ static ssize_t ctxid_val_store(struct device *dev, >> >> spin_lock(&drvdata->spinlock); >> idx = drvdata->ctxid_idx; >> - drvdata->ctxid_val[idx] = (u64)val; >> + drvdata->ctxid_pid[idx] = (u64)val; >> spin_unlock(&drvdata->spinlock); >> return size; >> } >> -static DEVICE_ATTR_RW(ctxid_val); >> +static DEVICE_ATTR_RW(ctxid_pid); >> >> static ssize_t ctxid_masks_show(struct device *dev, >> struct device_attribute *attr, >> @@ -1949,7 +1949,7 @@ static ssize_t ctxid_masks_store(struct device *dev, >> */ >> for (j = 0; j < 8; j++) { >> if (maskbyte & 1) >> - drvdata->ctxid_val[i] &= ~(0xFF << (j * 8)); >> + drvdata->ctxid_pid[i] &= ~(0xFF << (j * 8)); >> maskbyte >>= 1; >> } >> /* Select the next ctxid comparator mask value */ >> @@ -2193,7 +2193,7 @@ static struct attribute *coresight_etmv4_attrs[] = { >> &dev_attr_res_idx.attr, >> &dev_attr_res_ctrl.attr, >> &dev_attr_ctxid_idx.attr, >> - &dev_attr_ctxid_val.attr, >> + &dev_attr_ctxid_pid.attr, >> &dev_attr_ctxid_masks.attr, >> &dev_attr_vmid_idx.attr, >> &dev_attr_vmid_val.attr, >> @@ -2514,7 +2514,7 @@ static void etm4_init_default_data(struct etmv4_drvdata *drvdata) >> } >> >> for (i = 0; i < drvdata->numcidc; i++) >> - drvdata->ctxid_val[i] = 0x0; >> + drvdata->ctxid_pid[i] = 0x0; >> drvdata->ctxid_mask0 = 0x0; >> drvdata->ctxid_mask1 = 0x0; >> >> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h >> index e08e983..1e8fb36 100644 >> --- a/drivers/hwtracing/coresight/coresight-etm4x.h >> +++ b/drivers/hwtracing/coresight/coresight-etm4x.h >> @@ -265,7 +265,7 @@ >> * @addr_type: Current status of the comparator register. >> * @ctxid_idx: Context ID index selector. >> * @ctxid_size: Size of the context ID field to consider. >> - * @ctxid_val: Value of the context ID comparator. >> + * @ctxid_pid: Value of the context ID comparator. >> * @ctxid_mask0:Context ID comparator mask for comparator 0-3. >> * @ctxid_mask1:Context ID comparator mask for comparator 4-7. >> * @vmid_idx: VM ID index selector. >> @@ -352,7 +352,7 @@ struct etmv4_drvdata { >> u8 addr_type[ETM_MAX_SINGLE_ADDR_CMP]; >> u8 ctxid_idx; >> u8 ctxid_size; >> - u64 ctxid_val[ETMv4_MAX_CTXID_CMP]; >> + u64 ctxid_pid[ETMv4_MAX_CTXID_CMP]; >> u32 ctxid_mask0; >> u32 ctxid_mask1; >> u8 vmid_idx; >> > > > -- > Qualcomm Innovation Center, Inc. > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project
On 08/27/2015 11:12 AM, Mathieu Poirier wrote: > On 26 August 2015 at 11:57, Christopher Covington <cov@codeaurora.org> wrote: >> On 07/07/2015 04:41 AM, Chunyan Zhang wrote: >>> 'ctxid_val' array was used to store the value of ETM context ID comparator >>> which actually stores the process ID to be traced, so using 'ctxid_pid' as >>> its name instead make it easier to understand. >> >> Previous discussion with some ARM folks has led me to believe there isn't a >> guarantee that the Context ID Register will always have a PID. Why not allow >> filtering on thread group ID, session ID, cgroup related identifiers, etc.? > > Coresight tracers only support contextID tracing. The HW > automatically does the match between the contextID comparator register > in the tracer with the contextID register of the core. Tracing is > enabled if both values match (and the tracer is configured to do so). Is there a reason to only ever allow Process IDs to be written into the Coresight and CPU Context ID registers? Is there anything in the hardware that would prevent writing, for example, Thread Group IDs into the Coresight and CPU Context ID registers? If there's no hardware limitation, why should there be kernel or device tree architecture that states or implies that patches to support such a use case are unacceptable? Thanks, Christopher Covington
On 27 August 2015 at 09:33, Christopher Covington <cov@codeaurora.org> wrote: > On 08/27/2015 11:12 AM, Mathieu Poirier wrote: >> On 26 August 2015 at 11:57, Christopher Covington <cov@codeaurora.org> wrote: >>> On 07/07/2015 04:41 AM, Chunyan Zhang wrote: >>>> 'ctxid_val' array was used to store the value of ETM context ID comparator >>>> which actually stores the process ID to be traced, so using 'ctxid_pid' as >>>> its name instead make it easier to understand. >>> >>> Previous discussion with some ARM folks has led me to believe there isn't a >>> guarantee that the Context ID Register will always have a PID. Why not allow >>> filtering on thread group ID, session ID, cgroup related identifiers, etc.? >> >> Coresight tracers only support contextID tracing. The HW >> automatically does the match between the contextID comparator register >> in the tracer with the contextID register of the core. Tracing is >> enabled if both values match (and the tracer is configured to do so). > > Is there a reason to only ever allow Process IDs to be written into the > Coresight and CPU Context ID registers? Is there anything in the hardware that > would prevent writing, for example, Thread Group IDs into the Coresight and > CPU Context ID registers? If there's no hardware limitation, why should there > be kernel or device tree architecture that states or implies that patches to > support such a use case are unacceptable? I'm not saying your idea is unacceptable - I actually think there is value in it. At this time the scheduler will automatically write the PID to the contextID register when a task is running, a reality this feature is exploiting. There is no limitation as to what can be written to the coresight contextID register - tracing will start for as long as the values and mask are configured properly. I do not know the limitation imposed on the core's contextID register (if any). We'd also have to make sure that all the code, everywhere, relying on that information has been modified to take into account the new semantic. > > Thanks, > Christopher Covington > > -- > Qualcomm Innovation Center, Inc. > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project
diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x index 2fe2e3d..2355ed8 100644 --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x @@ -249,7 +249,7 @@ KernelVersion: 4.01 Contact: Mathieu Poirier <mathieu.poirier@linaro.org> Description: (RW) Select which context ID comparator to work with. -What: /sys/bus/coresight/devices/<memory_map>.etm/ctxid_val +What: /sys/bus/coresight/devices/<memory_map>.etm/ctxid_pid Date: April 2015 KernelVersion: 4.01 Contact: Mathieu Poirier <mathieu.poirier@linaro.org> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c index 1312e99..9afbda5 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.c +++ b/drivers/hwtracing/coresight/coresight-etm4x.c @@ -155,7 +155,7 @@ static void etm4_enable_hw(void *info) drvdata->base + TRCACATRn(i)); } for (i = 0; i < drvdata->numcidc; i++) - writeq_relaxed(drvdata->ctxid_val[i], + writeq_relaxed(drvdata->ctxid_pid[i], drvdata->base + TRCCIDCVRn(i)); writel_relaxed(drvdata->ctxid_mask0, drvdata->base + TRCCIDCCTLR0); writel_relaxed(drvdata->ctxid_mask1, drvdata->base + TRCCIDCCTLR1); @@ -507,7 +507,7 @@ static ssize_t reset_store(struct device *dev, drvdata->ctxid_idx = 0x0; for (i = 0; i < drvdata->numcidc; i++) - drvdata->ctxid_val[i] = 0x0; + drvdata->ctxid_pid[i] = 0x0; drvdata->ctxid_mask0 = 0x0; drvdata->ctxid_mask1 = 0x0; @@ -1815,7 +1815,7 @@ static ssize_t ctxid_idx_store(struct device *dev, } static DEVICE_ATTR_RW(ctxid_idx); -static ssize_t ctxid_val_show(struct device *dev, +static ssize_t ctxid_pid_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -1825,12 +1825,12 @@ static ssize_t ctxid_val_show(struct device *dev, spin_lock(&drvdata->spinlock); idx = drvdata->ctxid_idx; - val = (unsigned long)drvdata->ctxid_val[idx]; + val = (unsigned long)drvdata->ctxid_pid[idx]; spin_unlock(&drvdata->spinlock); return scnprintf(buf, PAGE_SIZE, "%#lx\n", val); } -static ssize_t ctxid_val_store(struct device *dev, +static ssize_t ctxid_pid_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { @@ -1850,11 +1850,11 @@ static ssize_t ctxid_val_store(struct device *dev, spin_lock(&drvdata->spinlock); idx = drvdata->ctxid_idx; - drvdata->ctxid_val[idx] = (u64)val; + drvdata->ctxid_pid[idx] = (u64)val; spin_unlock(&drvdata->spinlock); return size; } -static DEVICE_ATTR_RW(ctxid_val); +static DEVICE_ATTR_RW(ctxid_pid); static ssize_t ctxid_masks_show(struct device *dev, struct device_attribute *attr, @@ -1949,7 +1949,7 @@ static ssize_t ctxid_masks_store(struct device *dev, */ for (j = 0; j < 8; j++) { if (maskbyte & 1) - drvdata->ctxid_val[i] &= ~(0xFF << (j * 8)); + drvdata->ctxid_pid[i] &= ~(0xFF << (j * 8)); maskbyte >>= 1; } /* Select the next ctxid comparator mask value */ @@ -2193,7 +2193,7 @@ static struct attribute *coresight_etmv4_attrs[] = { &dev_attr_res_idx.attr, &dev_attr_res_ctrl.attr, &dev_attr_ctxid_idx.attr, - &dev_attr_ctxid_val.attr, + &dev_attr_ctxid_pid.attr, &dev_attr_ctxid_masks.attr, &dev_attr_vmid_idx.attr, &dev_attr_vmid_val.attr, @@ -2514,7 +2514,7 @@ static void etm4_init_default_data(struct etmv4_drvdata *drvdata) } for (i = 0; i < drvdata->numcidc; i++) - drvdata->ctxid_val[i] = 0x0; + drvdata->ctxid_pid[i] = 0x0; drvdata->ctxid_mask0 = 0x0; drvdata->ctxid_mask1 = 0x0; diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h index e08e983..1e8fb36 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.h +++ b/drivers/hwtracing/coresight/coresight-etm4x.h @@ -265,7 +265,7 @@ * @addr_type: Current status of the comparator register. * @ctxid_idx: Context ID index selector. * @ctxid_size: Size of the context ID field to consider. - * @ctxid_val: Value of the context ID comparator. + * @ctxid_pid: Value of the context ID comparator. * @ctxid_mask0:Context ID comparator mask for comparator 0-3. * @ctxid_mask1:Context ID comparator mask for comparator 4-7. * @vmid_idx: VM ID index selector. @@ -352,7 +352,7 @@ struct etmv4_drvdata { u8 addr_type[ETM_MAX_SINGLE_ADDR_CMP]; u8 ctxid_idx; u8 ctxid_size; - u64 ctxid_val[ETMv4_MAX_CTXID_CMP]; + u64 ctxid_pid[ETMv4_MAX_CTXID_CMP]; u32 ctxid_mask0; u32 ctxid_mask1; u8 vmid_idx;