CoreSight April 2025

coresight@lists.linaro.org

10 participants
54 discussions

[PATCH v4 0/7] Arm CoreSight: Support AUX pause and resume

by Leo Yan

This series is to enable AUX pause and resume on Arm CoreSight. The first patch extracts the trace unit controlling operations to two functions. These two functions will be used by AUX pause and resume. Patches 02 and 03 change the ETMv4 driver to prepare callback functions for AUX pause and resume. Patch 04 changes the ETM perf layer to support AUX pause and resume in a perf session. The patch 05 re-enables sinks after buffer update, based on it, the patch 06 updates buffer on AUX pause occasion, which can mitigate the trace data lose issue. Patch 07 documents the AUX pause usages with Arm CoreSight. This patch set has been verified on the Hikey960 board. It is suggested to disable CPUIdle (add `nohlt` option in Linux command line) when verifying this series. ETM and funnel drivers are found issues during CPU suspend and resume which will be addressed separately. Changes from v3: - Re-enabled sink in buffer update callbacks (Suzuki). Changes from v2: - Rebased on CoreSight next branch. - Dropped the uAPI 'update_buf_on_pause' and updated document respectively (Suzuki). - Renamed ETM callbacks to .pause_perf() and .resume_perf() (Suzuki). - Minor improvement for error handling in the AUX resume flow. Changes from v1: - Added validation function pointers in pause and resume APIs (Mike). Leo Yan (7): coresight: etm4x: Extract the trace unit controlling coresight: Introduce pause and resume APIs for source coresight: etm4x: Hook pause and resume callbacks coresight: perf: Support AUX trace pause and resume coresight: tmc: Re-enable sink after buffer update coresight: perf: Update buffer on AUX pause Documentation: coresight: Document AUX pause and resume Documentation/trace/coresight/coresight-perf.rst | 31 +++++++++ drivers/hwtracing/coresight/coresight-core.c | 22 +++++++ drivers/hwtracing/coresight/coresight-etm-perf.c | 84 +++++++++++++++++++++++- drivers/hwtracing/coresight/coresight-etm4x-core.c | 143 +++++++++++++++++++++++++++++------------ drivers/hwtracing/coresight/coresight-etm4x.h | 2 + drivers/hwtracing/coresight/coresight-priv.h | 2 + drivers/hwtracing/coresight/coresight-tmc-etf.c | 9 +++ drivers/hwtracing/coresight/coresight-tmc-etr.c | 10 +++ include/linux/coresight.h | 4 ++ 9 files changed, 265 insertions(+), 42 deletions(-) -- 2.34.1

1 week, 4 days

[PATCH v3 0/2] coresight: Add Coresight Trace Network On Chip driver

by Yuanfang Zhang

The Trace Network On Chip (TNOC) is an integration hierarchy which is a hardware component that integrates the functionalities of TPDA and funnels. It collects trace form subsystems and transfers to coresight sink. Signed-off-by: Yuanfang Zhang <quic_yuanfang(a)quicinc.com> --- Changes in v3: - Remove unnecessary sysfs nodes. - update commit messages. - Use 'writel' instead of 'write_relaxed' when writing to the register for the last time. - Add trace_id ops. - Link to v2: https://lore.kernel.org/r/20250226-trace-noc-driver-v2-0-8afc6584afc5@quici… Changes in v2: - Modified the format of DT binging file. - Fix compile warnings. - Link to v1: https://lore.kernel.org/r/46643089-b88d-49dc-be05-7bf0bb21f847@quicinc.com --- Yuanfang Zhang (2): dt-bindings: arm: Add device Trace Network On Chip definition coresight: add coresight Trace Network On Chip driver .../bindings/arm/qcom,coresight-tnoc.yaml | 111 ++++++++++++ drivers/hwtracing/coresight/Kconfig | 13 ++ drivers/hwtracing/coresight/Makefile | 1 + drivers/hwtracing/coresight/coresight-tnoc.c | 186 +++++++++++++++++++++ drivers/hwtracing/coresight/coresight-tnoc.h | 34 ++++ 5 files changed, 345 insertions(+) --- base-commit: a2cc6ff5ec8f91bc463fd3b0c26b61166a07eb11 change-id: 20250403-trace-noc-f8286b30408e Best regards, -- Yuanfang Zhang <quic_yuanfang(a)quicinc.com>

2 weeks, 2 days

[PATCH v2 0/9] coresight: Fix and improve clock usage

by Leo Yan

This series fixes and improves clock usage in the Arm CoreSight drivers. Based on the DT binding documents, the trace clock (atclk) is defined in some CoreSight modules, but support is absent. In most cases, the issue is hidden because the atclk clock is shared by multiple CoreSight modules and the clock is enabled anyway by other drivers. The first three patches address this issue. The programming clock (pclk) management in CoreSight drivers does not use the devm_XXX() variant APIs, the drivers needs to manually disable and release clocks for errors and for normal module exit. However, the drivers miss to disable clocks during module exit. The atclk may also not be disabled in CoreSight drivers during module exit. By using devm APIs, patches 04 and 05 fix clock disabling issues. Another issue is pclk might be enabled twice in init phase - once by AMBA bus driver, and again by CoreSight drivers. This is fixed in patch 06. Patches 07 to 09 refactor the clock related code. Patch 07 consolidats the clock initialization into a central place. Patch 08 makes the clock enabling sequence consistent. Patch 09 removes redundant condition checks and adds error handling in runtime PM. This series is verified on Arm64 Hikey960 platform. Changes from v1: - Moved the coresight_get_enable_clocks() function into CoreSight core layer (James). - Added comments for clock naming "apb_pclk" and "apb" (James). - Re-ordered patches for easier understanding (Anshuman). - Minor improvement for commit log in patch 01 (Anshuman). Leo Yan (9): coresight: tmc: Support atclk coresight: catu: Support atclk coresight: etm4x: Support atclk coresight: Disable programming clock properly coresight: Disable trace bus clock properly coresight: Avoid enable programming clock duplicately coresight: Consolidate clock enabling coresight: Make clock sequence consistent coresight: Refactor runtime PM drivers/hwtracing/coresight/coresight-catu.c | 53 ++++++++++++++++----------------- drivers/hwtracing/coresight/coresight-catu.h | 1 + drivers/hwtracing/coresight/coresight-core.c | 45 ++++++++++++++++++++++++++++ drivers/hwtracing/coresight/coresight-cpu-debug.c | 41 +++++++++----------------- drivers/hwtracing/coresight/coresight-ctcu-core.c | 24 +++++---------- drivers/hwtracing/coresight/coresight-etb10.c | 18 ++++-------- drivers/hwtracing/coresight/coresight-etm3x-core.c | 17 ++++------- drivers/hwtracing/coresight/coresight-etm4x-core.c | 32 ++++++++++---------- drivers/hwtracing/coresight/coresight-etm4x.h | 4 ++- drivers/hwtracing/coresight/coresight-funnel.c | 66 +++++++++++++++--------------------------- drivers/hwtracing/coresight/coresight-replicator.c | 63 ++++++++++++++-------------------------- drivers/hwtracing/coresight/coresight-stm.c | 34 +++++++++------------- drivers/hwtracing/coresight/coresight-tmc-core.c | 48 +++++++++++++++--------------- drivers/hwtracing/coresight/coresight-tmc.h | 2 ++ drivers/hwtracing/coresight/coresight-tpiu.c | 36 ++++++++++------------- include/linux/coresight.h | 30 ++----------------- 16 files changed, 225 insertions(+), 289 deletions(-) -- 2.34.1

2 weeks, 3 days

[PATCH v4 0/2] coresight: Add Coresight Trace Network On Chip driver

by Yuanfang Zhang

The Trace Network On Chip (TNOC) is an integration hierarchy which is a hardware component that integrates the functionalities of TPDA and funnels. It collects trace form subsystems and transfers to coresight sink. Signed-off-by: Yuanfang Zhang <quic_yuanfang(a)quicinc.com> --- Changes in v4: - Fix dt_binding warning. - update mask of trace_noc amba_id. - Modify driver comments. - rename TRACE_NOC_SYN_VAL to TRACE_NOC_SYNC_INTERVAL. - Link to v3: https://lore.kernel.org/r/20250411-trace-noc-v3-0-1f19ddf7699b@quicinc.com Changes in v3: - Remove unnecessary sysfs nodes. - update commit messages. - Use 'writel' instead of 'write_relaxed' when writing to the register for the last time. - Add trace_id ops. - Link to v2: https://lore.kernel.org/r/20250226-trace-noc-driver-v2-0-8afc6584afc5@quici… Changes in v2: - Modified the format of DT binging file. - Fix compile warnings. - Link to v1: https://lore.kernel.org/r/46643089-b88d-49dc-be05-7bf0bb21f847@quicinc.com --- Yuanfang Zhang (2): dt-bindings: arm: Add device Trace Network On Chip definition coresight: add coresight Trace Network On Chip driver .../bindings/arm/qcom,coresight-tnoc.yaml | 111 ++++++++++++ drivers/hwtracing/coresight/Kconfig | 13 ++ drivers/hwtracing/coresight/Makefile | 1 + drivers/hwtracing/coresight/coresight-tnoc.c | 191 +++++++++++++++++++++ drivers/hwtracing/coresight/coresight-tnoc.h | 34 ++++ 5 files changed, 350 insertions(+) --- base-commit: a2cc6ff5ec8f91bc463fd3b0c26b61166a07eb11 change-id: 20250403-trace-noc-f8286b30408e Best regards, -- Yuanfang Zhang <quic_yuanfang(a)quicinc.com>

2 weeks, 3 days

[PATCH] coresight: Disable MMIO logging for coresight stm driver

by Mao Jinlong

When read/write registers with readl_relaxed and writel_relaxed, log_read_mmio and log_write_mmio will be called. If mmio trace is enabled to STM, STM driver will write the register to send the trace and writel_relaxed will be called again. The circular call like callstack below will happen. Disable mmio logging for stm driver to avoid this issue. [] stm_source_write[stm_core]+0xc4 [] stm_ftrace_write[stm_ftrace]+0x40 [] trace_event_buffer_commit+0x238 [] trace_event_raw_event_rwmmio_rw_template+0x8c [] log_post_write_mmio+0xb4 [] writel_relaxed[coresight_stm]+0x80 [] stm_generic_packet[coresight_stm]+0x1a8 [] stm_data_write[stm_core]+0x78 [] ost_write[stm_p_ost]+0xc8 [] stm_source_write[stm_core]+0x7c [] stm_ftrace_write[stm_ftrace]+0x40 [] trace_event_buffer_commit+0x238 [] trace_event_raw_event_rwmmio_read+0x84 [] log_read_mmio+0xac [] readl_relaxed[coresight_tmc]+0x50 Signed-off-by: Mao Jinlong <quic_jinlmao(a)quicinc.com> --- drivers/hwtracing/coresight/Makefile | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile index 4ba478211b31..f3158266f75e 100644 --- a/drivers/hwtracing/coresight/Makefile +++ b/drivers/hwtracing/coresight/Makefile @@ -22,6 +22,8 @@ condflags := \ $(call cc-option, -Wstringop-truncation) subdir-ccflags-y += $(condflags) +CFLAGS_coresight-stm.o := -D__DISABLE_TRACE_MMIO__ + obj-$(CONFIG_CORESIGHT) += coresight.o coresight-y := coresight-core.o coresight-etm-perf.o coresight-platform.o \ coresight-sysfs.o coresight-syscfg.o coresight-config.o \ -- 2.25.1

2 weeks, 4 days

[PATCH v4] coresight: Add a KUnit test for coresight_find_default_sink()

by James Clark

Add a test to confirm that default sink selection skips over an ETF and returns an ETR even if it's further away. This also makes it easier to add new unit tests in the future. Reviewed-by: Leo Yan <leo.yan(a)arm.com> Signed-off-by: James Clark <james.clark(a)linaro.org> --- Changes in v4: - Rename etm to src now that it's not CORESIGHT_DEV_SUBTYPE_SOURCE_PROC - Remove the now empty src_ops too - Fix a rebase mistake in the Makefile that removed CTCU - Link to v3: https://lore.kernel.org/r/20250312-james-cs-kunit-test-v3-1-dcfb69730161@li… Changes in v3: - Use CORESIGHT_DEV_SUBTYPE_SOURCE_BUS type instead of the default (CORESIGHT_DEV_SUBTYPE_SOURCE_PROC) so that the test still works even when TRBE sinks are registered. This also removes the need for the fake CPU ID callback. - Link to v2: https://lore.kernel.org/r/20250305-james-cs-kunit-test-v2-1-83ba682b976c@li… Changes in v2: - Let devm free everything rather than doing individual kfrees: "Like with managed drivers, KUnit-managed fake devices are automatically cleaned up when the test finishes, but can be manually cleaned up early with kunit_device_unregister()." - Link to v1: https://lore.kernel.org/r/20250225164639.522741-1-james.clark@linaro.org --- drivers/hwtracing/coresight/Kconfig | 9 +++ drivers/hwtracing/coresight/Makefile | 1 + drivers/hwtracing/coresight/coresight-core.c | 1 + .../hwtracing/coresight/coresight-kunit-tests.c | 74 ++++++++++++++++++++++ 4 files changed, 85 insertions(+) diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig index ecd7086a5b83..f064e3d172b3 100644 --- a/drivers/hwtracing/coresight/Kconfig +++ b/drivers/hwtracing/coresight/Kconfig @@ -259,4 +259,13 @@ config CORESIGHT_DUMMY To compile this driver as a module, choose M here: the module will be called coresight-dummy. + +config CORESIGHT_KUNIT_TESTS + tristate "Enable Coresight unit tests" + depends on KUNIT + default KUNIT_ALL_TESTS + help + Enable Coresight unit tests. Only useful for development and not + intended for production. + endif diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile index 8e62c3150aeb..4e6ea5b05b01 100644 --- a/drivers/hwtracing/coresight/Makefile +++ b/drivers/hwtracing/coresight/Makefile @@ -53,3 +53,4 @@ obj-$(CONFIG_ULTRASOC_SMB) += ultrasoc-smb.o obj-$(CONFIG_CORESIGHT_DUMMY) += coresight-dummy.o obj-$(CONFIG_CORESIGHT_CTCU) += coresight-ctcu.o coresight-ctcu-y := coresight-ctcu-core.o +obj-$(CONFIG_CORESIGHT_KUNIT_TESTS) += coresight-kunit-tests.o diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index fb43ef6a3b1f..47af75ba7a00 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -959,6 +959,7 @@ coresight_find_default_sink(struct coresight_device *csdev) } return csdev->def_sink; } +EXPORT_SYMBOL_GPL(coresight_find_default_sink); static int coresight_remove_sink_ref(struct device *dev, void *data) { diff --git a/drivers/hwtracing/coresight/coresight-kunit-tests.c b/drivers/hwtracing/coresight/coresight-kunit-tests.c new file mode 100644 index 000000000000..c8f361767c45 --- /dev/null +++ b/drivers/hwtracing/coresight/coresight-kunit-tests.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <kunit/test.h> +#include <kunit/device.h> +#include <linux/coresight.h> + +#include "coresight-priv.h" + +static struct coresight_device *coresight_test_device(struct device *dev) +{ + struct coresight_device *csdev = devm_kcalloc(dev, 1, + sizeof(struct coresight_device), + GFP_KERNEL); + csdev->pdata = devm_kcalloc(dev, 1, + sizeof(struct coresight_platform_data), + GFP_KERNEL); + return csdev; +} + +static void test_default_sink(struct kunit *test) +{ + /* + * Source -> ETF -> ETR -> CATU + * ^ + * | default + */ + struct device *dev = kunit_device_register(test, "coresight_kunit"); + struct coresight_device *src = coresight_test_device(dev), + *etf = coresight_test_device(dev), + *etr = coresight_test_device(dev), + *catu = coresight_test_device(dev); + struct coresight_connection conn = {}; + + src->type = CORESIGHT_DEV_TYPE_SOURCE; + /* + * Don't use CORESIGHT_DEV_SUBTYPE_SOURCE_PROC, that would always return + * a TRBE sink if one is registered. + */ + src->subtype.source_subtype = CORESIGHT_DEV_SUBTYPE_SOURCE_BUS; + etf->type = CORESIGHT_DEV_TYPE_LINKSINK; + etf->subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER; + etr->type = CORESIGHT_DEV_TYPE_SINK; + etr->subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_SYSMEM; + catu->type = CORESIGHT_DEV_TYPE_HELPER; + + conn.src_dev = src; + conn.dest_dev = etf; + coresight_add_out_conn(dev, src->pdata, &conn); + + conn.src_dev = etf; + conn.dest_dev = etr; + coresight_add_out_conn(dev, etf->pdata, &conn); + + conn.src_dev = etr; + conn.dest_dev = catu; + coresight_add_out_conn(dev, etr->pdata, &conn); + + KUNIT_ASSERT_PTR_EQ(test, coresight_find_default_sink(src), etr); +} + +static struct kunit_case coresight_testcases[] = { + KUNIT_CASE(test_default_sink), + {} +}; + +static struct kunit_suite coresight_test_suite = { + .name = "coresight_test_suite", + .test_cases = coresight_testcases, +}; + +kunit_test_suites(&coresight_test_suite); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("James Clark <james.clark(a)linaro.org>"); +MODULE_DESCRIPTION("Arm CoreSight KUnit tests"); --- base-commit: 3eadce8308bc8d808fd9e3a9d211c84215087451 change-id: 20250305-james-cs-kunit-test-3af1df2401e6 Best regards, -- James Clark <james.clark(a)linaro.org>

3 weeks, 1 day

[PATCH v4 0/7] coresight: Clear self hosted claim tag on probe

by James Clark

I've gotten stuck a few times with unusable Coresight after a warm boot due to lingering claim tags, especially when testing the Coresight panic patchsets. This change does some tidy ups, adds some debug messages and clears the self hosted claim tag on probe. The last two commits are unrelated tidyups but they touch some of the same functions so to avoid extra conflicts I'm including them here. This gets as far as fixing the claim tag issue, but there is some other state not being cleared on probe that results in the following error. This can be fixed up as a later change: coresight tmc_etf0: timeout while waiting for TMC to be Ready coresight tmc_etf0: Failed to enable : TMC is not ready Changes in v4: - Add _unlocked() suffix for consistency - s/cs_access/csdev_access/ - Link to v3: https://lore.kernel.org/r/20250320-james-coresight-claim-tags-v3-0-d3145c15… Changes in v3: - Collapse rename and locked/unlocked addition commits of coresight_clear_self_claim_tag() so we don't change the name twice. - Make coresight_clear_self_claim_tag() a bit more generic by only doing UNLOCK for MMIO devices (although there is no use of this right now) - Link to v2: https://lore.kernel.org/r/20250318-james-coresight-claim-tags-v2-0-e9c8a9cd… Changes in v2: * Revert most of the interface changes, just call coresight_clear_self_claim_tag() directly. This is possible because we're not doing the read first, so it has fewer knock on effects. * Split out the change to add struct cs_access to etm3x * Add another warning for racing with external debugger -- 2.34.1 --- James Clark (7): coresight: Convert tag clear function to take a struct csdev_access coresight: Only check bottom two claim bits coresight: Add claim tag warnings and debug messages coresight: etm3x: Convert raw base pointer to struct coresight access coresight: Clear self hosted claim tag on probe coresight: Remove inlines from static function definitions coresight: Remove extern from function declarations drivers/hwtracing/coresight/coresight-catu.c | 12 +-- drivers/hwtracing/coresight/coresight-core.c | 87 ++++++++++++++-------- drivers/hwtracing/coresight/coresight-cti-core.c | 2 + drivers/hwtracing/coresight/coresight-etb10.c | 4 +- drivers/hwtracing/coresight/coresight-etm.h | 6 +- drivers/hwtracing/coresight/coresight-etm3x-core.c | 28 +++---- .../hwtracing/coresight/coresight-etm3x-sysfs.c | 8 +- drivers/hwtracing/coresight/coresight-etm4x-core.c | 10 ++- .../hwtracing/coresight/coresight-etm4x-sysfs.c | 4 +- drivers/hwtracing/coresight/coresight-funnel.c | 1 + drivers/hwtracing/coresight/coresight-platform.c | 26 +++---- drivers/hwtracing/coresight/coresight-priv.h | 20 ++--- drivers/hwtracing/coresight/coresight-replicator.c | 3 +- drivers/hwtracing/coresight/coresight-stm.c | 6 +- .../coresight/coresight-syscfg-configfs.c | 2 +- drivers/hwtracing/coresight/coresight-tmc-core.c | 9 ++- drivers/hwtracing/coresight/coresight-tmc-etr.c | 16 ++-- drivers/hwtracing/coresight/coresight-trbe.c | 18 ++--- include/linux/coresight.h | 40 +++++----- 19 files changed, 168 insertions(+), 134 deletions(-) --- base-commit: 5442d22da7dbff3ba8c6720fc6f23ea4934d402d change-id: 20250317-james-coresight-claim-tags-ae1461f1f5e0 Best regards, -- James Clark <james.clark(a)linaro.org>

3 weeks, 2 days

Re: [PATCH v5 0/2] coresight: catu: Introduce refcount and spinlock for enabling/disabling

by Suzuki K Poulose

On Tue, 29 Apr 2025 16:12:58 -0700, Yabin Cui wrote: > When tracing ETM data on multiple CPUs concurrently via the > perf interface, the CATU device is shared across different CPU > paths. This can lead to race conditions when multiple CPUs attempt > to enable or disable the CATU device simultaneously. This patchset > is to fix race conditions when enabling/disabling a CATU device. > > Changes since v4: > - Collect Review-by tags. > - return -EINVAL for unknown types in coresight_enable_path. > > [...] Applied, thanks! [1/2] coresight: catu: Introduce refcount and spinlock for enabling/disabling https://git.kernel.org/coresight/c/a03a0a08 [2/2] coresight: core: Disable helpers for devices that fail to enable https://git.kernel.org/coresight/c/f6028eee Best regards, -- Suzuki K Poulose <suzuki.poulose(a)arm.com>

3 weeks, 2 days

Re: [PATCH v5 2/2] coresight: core: Disable helpers for devices that fail to enable

by Suzuki K Poulose

On 30/04/2025 00:13, Yabin Cui wrote: > When enabling a SINK or LINK type coresight device fails, the > associated helpers should be disabled. > > Signed-off-by: Yabin Cui <yabinc(a)google.com> > Suggested-by: Suzuki K Poulose <suzuki.poulose(a)arm.com> > Reviewed-by: James Clark <james.clark(a)linaro.org> > Reviewed-by: Mike Leach <mike.leach(a)linaro.org> Again, this should have : Fixes: 6148652807ba ("coresight: Enable and disable helper devices adjacent to the path") I have added it locally Rest looks good to me Suzuki > --- > drivers/hwtracing/coresight/coresight-core.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c > index dabec7073aed..d3523f0262af 100644 > --- a/drivers/hwtracing/coresight/coresight-core.c > +++ b/drivers/hwtracing/coresight/coresight-core.c > @@ -465,7 +465,7 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode, > /* Enable all helpers adjacent to the path first */ > ret = coresight_enable_helpers(csdev, mode, path); > if (ret) > - goto err; > + goto err_disable_path; > /* > * ETF devices are tricky... They can be a link or a sink, > * depending on how they are configured. If an ETF has been > @@ -486,8 +486,10 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode, > * that need disabling. Disabling the path here > * would mean we could disrupt an existing session. > */ > - if (ret) > + if (ret) { > + coresight_disable_helpers(csdev, path); > goto out; > + } > break; > case CORESIGHT_DEV_TYPE_SOURCE: > /* sources are enabled from either sysFS or Perf */ > @@ -497,16 +499,19 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode, > child = list_next_entry(nd, link)->csdev; > ret = coresight_enable_link(csdev, parent, child, source); > if (ret) > - goto err; > + goto err_disable_helpers; > break; > default: > - goto err; > + ret = -EINVAL; > + goto err_disable_helpers; > } > } > > out: > return ret; > -err: > +err_disable_helpers: > + coresight_disable_helpers(csdev, path); > +err_disable_path: > coresight_disable_path_from(path, nd); > goto out; > }

3 weeks, 2 days

Re: [PATCH v5 1/2] coresight: catu: Introduce refcount and spinlock for enabling/disabling

by Suzuki K Poulose

On 30/04/2025 00:12, Yabin Cui wrote: > When tracing ETM data on multiple CPUs concurrently via the > perf interface, the CATU device is shared across different CPU > paths. This can lead to race conditions when multiple CPUs attempt > to enable or disable the CATU device simultaneously. > > To address these race conditions, this patch introduces the > following changes: > > 1. The enable and disable operations for the CATU device are not > reentrant. Therefore, a spinlock is added to ensure that only > one CPU can enable or disable a given CATU device at any point > in time. > > 2. A reference counter is used to manage the enable/disable state > of the CATU device. The device is enabled when the first CPU > requires it and is only disabled when the last CPU finishes > using it. This ensures the device remains active as long as at > least one CPU needs it. > > Signed-off-by: Yabin Cui <yabinc(a)google.com> > Reviewed-by: James Clark <james.clark(a)linaro.org> > Reviewed-by: Leo Yan <leo.yan(a)arm.com> Looks good to me, I will add : Fixes: fcacb5c154ba ("coresight: Introduce support for Coresight Address Translation Unit") Suzuki > --- > drivers/hwtracing/coresight/coresight-catu.c | 25 +++++++++++++------- > drivers/hwtracing/coresight/coresight-catu.h | 1 + > 2 files changed, 18 insertions(+), 8 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c > index 96cb48b140af..d4e2e175e077 100644 > --- a/drivers/hwtracing/coresight/coresight-catu.c > +++ b/drivers/hwtracing/coresight/coresight-catu.c > @@ -458,12 +458,17 @@ static int catu_enable_hw(struct catu_drvdata *drvdata, enum cs_mode cs_mode, > static int catu_enable(struct coresight_device *csdev, enum cs_mode mode, > void *data) > { > - int rc; > + int rc = 0; > struct catu_drvdata *catu_drvdata = csdev_to_catu_drvdata(csdev); > > - CS_UNLOCK(catu_drvdata->base); > - rc = catu_enable_hw(catu_drvdata, mode, data); > - CS_LOCK(catu_drvdata->base); > + guard(raw_spinlock_irqsave)(&catu_drvdata->spinlock); > + if (csdev->refcnt == 0) { > + CS_UNLOCK(catu_drvdata->base); > + rc = catu_enable_hw(catu_drvdata, mode, data); > + CS_LOCK(catu_drvdata->base); > + } > + if (!rc) > + csdev->refcnt++; > return rc; > } > > @@ -486,12 +491,15 @@ static int catu_disable_hw(struct catu_drvdata *drvdata) > > static int catu_disable(struct coresight_device *csdev, void *__unused) > { > - int rc; > + int rc = 0; > struct catu_drvdata *catu_drvdata = csdev_to_catu_drvdata(csdev); > > - CS_UNLOCK(catu_drvdata->base); > - rc = catu_disable_hw(catu_drvdata); > - CS_LOCK(catu_drvdata->base); > + guard(raw_spinlock_irqsave)(&catu_drvdata->spinlock); > + if (--csdev->refcnt == 0) { > + CS_UNLOCK(catu_drvdata->base); > + rc = catu_disable_hw(catu_drvdata); > + CS_LOCK(catu_drvdata->base); > + } > return rc; > } > > @@ -550,6 +558,7 @@ static int __catu_probe(struct device *dev, struct resource *res) > dev->platform_data = pdata; > > drvdata->base = base; > + raw_spin_lock_init(&drvdata->spinlock); > catu_desc.access = CSDEV_ACCESS_IOMEM(base); > catu_desc.pdata = pdata; > catu_desc.dev = dev; > diff --git a/drivers/hwtracing/coresight/coresight-catu.h b/drivers/hwtracing/coresight/coresight-catu.h > index 141feac1c14b..755776cd19c5 100644 > --- a/drivers/hwtracing/coresight/coresight-catu.h > +++ b/drivers/hwtracing/coresight/coresight-catu.h > @@ -65,6 +65,7 @@ struct catu_drvdata { > void __iomem *base; > struct coresight_device *csdev; > int irq; > + raw_spinlock_t spinlock; > }; > > #define CATU_REG32(name, offset) \

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