This series is extracted from [1], focusing on CoreSight path power
management.
Compared to the previous version, this series is updated heavily for:
1) Dropped the global per CPU variable for saving path pointers.
Instead, the activate path is now stored in the source device's
structure. This allows fetching the path pointer naturally based on
the source regardless of whether it is a per-CPU source or a system
source (such as STM).
This improvement addresses Mike's comment that, later we can polish
coresight-sysfs.c to remove the tracer_path variables.
2) To simplify the series and make it easier to review, the CTI driver
related fixes have been removed from this series and which will be
sent out separately.
3) This series disables the path when a CPU is hot-plugged off but does
not re-enable it when the CPU is subsequently hot-plugged in. This
simplifies the implementation and keep it consistent with the perf
session's behavior.
It also improves security, as there is no risk of unintended tracing
caused by a CPU being hot-plugged after a long period of inactivity.
This series is dependent on ETM driver's PM improvement series [2] and
has been verified on Juno-r2 and FVP RevC.
[1] https://lore.kernel.org/linux-arm-kernel/20250915-arm_coresight_power_manag…
[2] https://lore.kernel.org/linux-arm-kernel/20251103-arm_coresight_power_manag…
---
Changes in v4:
- Changed to store path pointer in coresight_device, this is easier for
fetching path pointer based on source device (Mike).
- Dropped changes in CTI driver.
- Only disabled path for CPU hot-plugged off but not enable path for
hot-plugged in.
- Removed James' test tags for modified patches.
- Link to v3: https://lore.kernel.org/r/20250915-arm_coresight_power_management_fix-v3-0-…
Signed-off-by: Leo Yan <leo.yan(a)arm.com>
---
Leo Yan (14):
coresight: sysfs: Validate CPU online status for per-CPU sources
coresight: Set per CPU source pointer
coresight: Register CPU PM notifier in core layer
coresight: etm4x: Hook CPU PM callbacks
coresight: Add callback to determine if PM is needed
coresight: etm4x: Remove redundant condition checks in save and restore
coresight: syscfg: Use spinlock to protect active variables
coresight: Introduce coresight_enable_source() helper
coresight: Save activated path into source device
coresight: Add 'in_idle' argument to enable/disable path functions
coresight: Control path during CPU idle
coresight: Add PM callbacks for percpu sink
coresight: Take hotplug lock in enable_source_store() for Sysfs mode
coresight: Move CPU hotplug callbacks to core layer
Yabin Cui (1):
coresight: trbe: Save and restore state across CPU low power state
drivers/hwtracing/coresight/coresight-catu.c | 1 +
drivers/hwtracing/coresight/coresight-core.c | 273 ++++++++++++++++++++-
drivers/hwtracing/coresight/coresight-ctcu-core.c | 1 +
drivers/hwtracing/coresight/coresight-cti-core.c | 1 +
drivers/hwtracing/coresight/coresight-dummy.c | 1 +
drivers/hwtracing/coresight/coresight-etb10.c | 1 +
drivers/hwtracing/coresight/coresight-etm-perf.c | 2 +-
drivers/hwtracing/coresight/coresight-etm3x-core.c | 1 +
drivers/hwtracing/coresight/coresight-etm4x-core.c | 137 ++---------
drivers/hwtracing/coresight/coresight-funnel.c | 1 +
drivers/hwtracing/coresight/coresight-priv.h | 3 +
drivers/hwtracing/coresight/coresight-replicator.c | 1 +
drivers/hwtracing/coresight/coresight-stm.c | 1 +
drivers/hwtracing/coresight/coresight-syscfg.c | 22 +-
drivers/hwtracing/coresight/coresight-syscfg.h | 2 +
drivers/hwtracing/coresight/coresight-sysfs.c | 12 +-
drivers/hwtracing/coresight/coresight-tmc-core.c | 1 +
drivers/hwtracing/coresight/coresight-tnoc.c | 2 +
drivers/hwtracing/coresight/coresight-tpda.c | 1 +
drivers/hwtracing/coresight/coresight-tpdm.c | 1 +
drivers/hwtracing/coresight/coresight-tpiu.c | 1 +
drivers/hwtracing/coresight/coresight-trbe.c | 85 ++++++-
drivers/hwtracing/coresight/ultrasoc-smb.c | 1 +
include/linux/coresight.h | 13 +
24 files changed, 425 insertions(+), 140 deletions(-)
---
base-commit: f9ac95561513e18c2a2cf8905355dc5f0e030c46
change-id: 20251104-arm_coresight_path_power_management_improvement-dab4966f8280
Best regards,
--
Leo Yan <leo.yan(a)arm.com>
This series is extracted from the CoreSight power management fixes and
refactoring [1], focusing on ETMv3/4 power management.
This series has been verified on Juno-r2 platform.
[1] https://lore.kernel.org/linux-arm-kernel/20250915-arm_coresight_power_manag…
---
Changes in v5:
- Added more info for removing redundant DSB in
etm4_{enable|disable}_trace_unit() (Suzuki/Levi).
- Dropped moving isb() out from etm4_{enable|disable}_trace_unit()
(Suzuki).
- Reordered patches to move fixes earlier.
- Link to v4: https://lore.kernel.org/r/20251024-arm_coresight_power_management_fix-v4-0-…
Changes in v4:
- Added patch 10 for retaining sequencer state in ETMv4 driver (Mike).
- Added Mike's review tags.
- Added James' test tags.
- Link to v3: https://lore.kernel.org/r/20250915-arm_coresight_power_management_fix-v3-0-…
Changes in v3:
- Fixed building failure in ETMv3 driver (kernel test robot).
- Refactoring ETMv3 change for checking CPU ID (Levi).
- Fixed NULL pointer issue during CPU idle (James).
- Fixed lockdep complaint for HARDIRQ-safe and HARDIRA-unsafe (James).
- Fixed acquiring mutex in atomic context (James).
- Rebased on the latest coresight-next branch.
- Link to v2: https://lore.kernel.org/r/20250701-arm_cs_pm_fix_v3-v2-0-23ebb864fcc1@arm.c…
Changes in v2:
- Refactored ETMv4 suspend and resume for reusing the normal enabling
and disabling flows (James).
- Used a per-CPU structure to maintain path pointers (James).
- Supported helpers in CPU PM flows (James).
- Fixed the SMP-safe access to device mode.
- Fixed the context synchronization in ETMv4x driver.
- Link to v1: https://lore.kernel.org/linux-arm-kernel/20250516160742.1200904-1-leo.yan@a…
Signed-off-by: Leo Yan <leo.yan(a)arm.com>
---
Leo Yan (11):
coresight: Change device mode to atomic type
coresight: etm4x: Always set tracer's device mode on target CPU
coresight: etm3x: Always set tracer's device mode on target CPU
coresight: etm4x: Correct polling IDLE bit
coresight: etm4x: Add context synchronization before enabling trace
coresight: etm4x: Properly control filter in CPU idle with FEAT_TRF
coresight: etm4x: Remove the redundant DSB
coresight: etm4x: Remove the state_needs_restore flag
coresight: etm4x: Add flag to control single-shot restart
coresight: etm4x: Retain sequencer state
coresight: etm4x: Reuse normal enable and disable logic in CPU idle
drivers/hwtracing/coresight/coresight-etm3x-core.c | 59 ++--
drivers/hwtracing/coresight/coresight-etm4x-core.c | 347 +++++++--------------
drivers/hwtracing/coresight/coresight-etm4x.h | 62 ----
include/linux/coresight.h | 25 +-
4 files changed, 157 insertions(+), 336 deletions(-)
---
base-commit: 6146a0f1dfae5d37442a9ddcba012add260bceb0
change-id: 20250909-arm_coresight_power_management_fix-139873f942e8
Best regards,
--
Leo Yan <leo.yan(a)arm.com>
On Thu, 25 Sep 2025 18:42:30 +0800, Jie Gan wrote:
> Patch 1:
> Fix the issue that the catu cannot correctly read the handle of the AUX
> event which is caused by the commit[1].
>
> [1] 080ee83cc361 ("Coresight: Change functions to accept the coresight_path")
>
> Exeception call trace:
> tmc_etr_get_buffer+0x30/0x80 [coresight_tmc] (P)
> catu_enable_hw+0xbc/0x3d0 [coresight_catu]
> catu_enable+0x70/0xe0 [coresight_catu]
> coresight_enable_path+0xb0/0x258 [coresight]
>
> [...]
Applied, thanks!
[1/3] coresight: tmc: add the handle of the event to the path
https://git.kernel.org/coresight/c/aaa5abcc9d44
[2/3] coresight: change helper_ops to accept coresight_path
https://git.kernel.org/coresight/c/94baedb51dea
[3/3] coresight: change the sink_ops to accept coresight_path
https://git.kernel.org/coresight/c/b139702a8896
Best regards,
--
Suzuki K Poulose <suzuki.poulose(a)arm.com>
On Tue, 21 Oct 2025 16:45:25 +0800, Xiaoqi Zhuang wrote:
> When ETR is enabled as CS_MODE_SYSFS, if the buffer size is changed
> and enabled again, currently sysfs_buf will point to the newly
> allocated memory(buf_new) and free the old memory(buf_old). But the
> etr_buf that is being used by the ETR remains pointed to buf_old, not
> updated to buf_new. In this case, it will result in a memory
> use-after-free issue.
>
> [...]
Applied, thanks!
[1/1] coresight: ETR: Fix ETR buffer use-after-free issue
https://git.kernel.org/coresight/c/35501ac3c7d4
Best regards,
--
Suzuki K Poulose <suzuki.poulose(a)arm.com>
On Fri, 07 Nov 2025 14:16:39 +0800, Jie Gan wrote:
> Remove the redundant check for drvdata data because the drvdata here already
> has been guarranted to be non-NULL.
>
>
Applied, thanks!
[1/1] coresight: tpdm: remove redundant check for drvdata
https://git.kernel.org/coresight/c/aa5edd1b5ece
Best regards,
--
Suzuki K Poulose <suzuki.poulose(a)arm.com>
On 07/11/2025 06:16, Jie Gan wrote:
> Remove the redundant check for drvdata data because the drvdata here already
> has been guarranted to be non-NULL.
>
> Fixes: 350ba15ae187 ("coresight-tpdm: Add nodes for dsb msr support")
> Fixes: 8e8804145a46 ("coresight-tpdm: Add msr register support for CMB")
This doesn't need to be backported as such, as it is a cleanup. I will
drop the Fixes tag and merge this.
Suzuki
> Signed-off-by: Jie Gan <jie.gan(a)oss.qualcomm.com>
> ---
> drivers/hwtracing/coresight/coresight-tpdm.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index 0e3896c12f07..06e0a905a67d 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -1402,11 +1402,11 @@ static int tpdm_probe(struct device *dev, struct resource *res)
> if (ret)
> return ret;
>
> - if (drvdata && tpdm_has_dsb_dataset(drvdata))
> + if (tpdm_has_dsb_dataset(drvdata))
> of_property_read_u32(drvdata->dev->of_node,
> "qcom,dsb-msrs-num", &drvdata->dsb_msr_num);
>
> - if (drvdata && tpdm_has_cmb_dataset(drvdata))
> + if (tpdm_has_cmb_dataset(drvdata))
> of_property_read_u32(drvdata->dev->of_node,
> "qcom,cmb-msrs-num", &drvdata->cmb_msr_num);
> } else {
>
> ---
> base-commit: df5d79720b152e7ff058f11ed7e88d5b5c8d2a0c
> change-id: 20251107-fix_tpdm_redundant_check-a5a7bad4b7c8
> prerequisite-change-id: 20251028-add_static_tpdm_support-1f62477857e2:v4
> prerequisite-patch-id: eda8dd6884b831cb10affc22477aece39c78b408
> prerequisite-patch-id: 7beb8b17d54ff21bc57eab10b56e6ffcfa4d1963
> prerequisite-patch-id: f6f1e78dba3f1d3b1191ab827adab5a3b7b2326a
>
> Best regards,
The sysfs files that change the operational parameters for TMC buffer_size,
stop_on_flush and trigger_cntr are writable when the TMC is in use.
The new values will have no effect and be silently ignored.
Alter the sysfs functions to return -EBUSY if the TMC is currently
in use, and also protect the write values using the spinlock.
Signed-off-by: Mike Leach <mike.leach(a)linaro.org>
---
.../hwtracing/coresight/coresight-tmc-core.c | 41 ++++++++++++++++---
1 file changed, 35 insertions(+), 6 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
index 36599c431be6..a1216a1f9681 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-core.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
@@ -489,15 +489,24 @@ static ssize_t trigger_cntr_store(struct device *dev,
const char *buf, size_t size)
{
int ret;
- unsigned long val;
+ unsigned long val, flags;
struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
ret = kstrtoul(buf, 16, &val);
if (ret)
return ret;
+ /* do not permit write if the sink is currently in use */
+ raw_spin_lock_irqsave(&drvdata->spinlock, flags);
+ if (coresight_get_mode(drvdata->csdev) != CS_MODE_DISABLED) {
+ ret = -EBUSY;
+ goto out;
+ }
drvdata->trigger_cntr = val;
- return size;
+ ret = size;
+out:
+ raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ return ret;
}
static DEVICE_ATTR_RW(trigger_cntr);
@@ -514,7 +523,7 @@ static ssize_t buffer_size_store(struct device *dev,
const char *buf, size_t size)
{
int ret;
- unsigned long val;
+ unsigned long val, flags;
struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
/* Only permitted for TMC-ETRs */
@@ -527,8 +536,18 @@ static ssize_t buffer_size_store(struct device *dev,
/* The buffer size should be page aligned */
if (val & (PAGE_SIZE - 1))
return -EINVAL;
+
+ /* do not permit write if the sink is currently in use */
+ raw_spin_lock_irqsave(&drvdata->spinlock, flags);
+ if (coresight_get_mode(drvdata->csdev) != CS_MODE_DISABLED) {
+ ret = -EBUSY;
+ goto out;
+ }
drvdata->size = val;
- return size;
+ ret = size;
+out:
+ raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ return ret;
}
static DEVICE_ATTR_RW(buffer_size);
@@ -547,17 +566,27 @@ static ssize_t stop_on_flush_store(struct device *dev,
{
int ret;
u8 val;
+ unsigned long flags;
struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
ret = kstrtou8(buf, 0, &val);
if (ret)
return ret;
+
+ /* do not permit write if the sink is currently in use */
+ raw_spin_lock_irqsave(&drvdata->spinlock, flags);
+ if (coresight_get_mode(drvdata->csdev) != CS_MODE_DISABLED) {
+ ret = -EBUSY;
+ goto out;
+ }
if (val)
drvdata->stop_on_flush = true;
else
drvdata->stop_on_flush = false;
-
- return size;
+ ret = size;
+out:
+ raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ return ret;
}
static DEVICE_ATTR_RW(stop_on_flush);
--
2.32.0
On Tue, 28 Oct 2025 18:11:39 +0800, Jie Gan wrote:
> The static TPDM function as a dummy source, however, it is essential
> to enable the port connected to the TPDA and configure the element size.
> Without this, the TPDA cannot correctly receive trace data from the
> static TPDM. Since the static TPDM does not require MMIO mapping to
> access its registers, a clock controller is not mandatory for its
> operation.
>
> [...]
Applied, thanks!
[1/3] dt-bindings: arm: document the static TPDM compatible
https://git.kernel.org/coresight/c/8d204b6f1f7a
[2/3] coresight: tpdm: add static tpdm support
https://git.kernel.org/coresight/c/14ae052f7947
Best regards,
--
Suzuki K Poulose <suzuki.poulose(a)arm.com>