CoreSight

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2529 discussions

Re: [PATCH] coresight: Fix possible deadlock with lock dependency

by Suzuki K Poulose

On 21/07/2022 14:03, Sudeep Holla wrote: > With lockdeps enabled, we get the following warning: > > ====================================================== > WARNING: possible circular locking dependency detected > ------------------------------------------------------ > kworker/u12:1/53 is trying to acquire lock: > ffff80000adce220 (coresight_mutex){+.+.}-{4:4}, at: coresight_set_assoc_ectdev_mutex+0x3c/0x5c > but task is already holding lock: > ffff80000add1f60 (ect_mutex){+.+.}-{4:4}, at: cti_probe+0x318/0x394 > > which lock already depends on the new lock. > the existing dependency chain (in reverse order) is: > > -> #1 (ect_mutex){+.+.}-{4:4}: > __mutex_lock_common+0xd8/0xe60 > mutex_lock_nested+0x44/0x50 > cti_add_assoc_to_csdev+0x4c/0x184 > coresight_register+0x2f0/0x314 > tmc_probe+0x33c/0x414 > > -> #0 (coresight_mutex){+.+.}-{4:4}: > __lock_acquire+0x1a20/0x32d0 > lock_acquire+0x160/0x308 > __mutex_lock_common+0xd8/0xe60 > mutex_lock_nested+0x44/0x50 > coresight_set_assoc_ectdev_mutex+0x3c/0x5c > cti_update_conn_xrefs+0x6c/0xf8 > cti_probe+0x33c/0x394 > > other info that might help us debug this: > Possible unsafe locking scenario: > CPU0 CPU1 > ---- ---- > lock(ect_mutex); > lock(coresight_mutex); > lock(ect_mutex); > lock(coresight_mutex); > *** DEADLOCK *** > > 4 locks held by kworker/u12:1/53: > #0: ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1fc/0x63c > #1: (deferred_probe_work){+.+.}-{0:0}, at: process_one_work+0x228/0x63c > #2: (&dev->mutex){....}-{4:4}, at: __device_attach+0x48/0x1a8 > #3: (ect_mutex){+.+.}-{4:4}, at: cti_probe+0x318/0x394 > > To fix the same, call cti_add_assoc_to_csdev without the holding > coresight_mutex and confine the locking while setting the associated > ect / cti device using coresight_set_assoc_ectdev_mutex(). > > Cc: Mathieu Poirier <mathieu.poirier(a)linaro.org> > Cc: Suzuki K Poulose <suzuki.poulose(a)arm.com> > Cc: Mike Leach <mike.leach(a)linaro.org> > Cc: Leo Yan <leo.yan(a)linaro.org> > Signed-off-by: Sudeep Holla <sudeep.holla(a)arm.com> Thanks for the fix. I will push this out at rc1 as fixes. Thanks Suzuki

3 years, 1 month

Re: [PATCH linux-next] coresight: use sysfs_emit() to instead of scnprintf()

by James Clark

On 27/09/2022 12:51, zhangsongyi.cgel(a)gmail.com wrote: > From: zhang songyi <zhang.songyi(a)zte.com.cn> > > Follow the advice of the Documentation/filesystems/sysfs.rst and show() > should only use sysfs_emit() or sysfs_emit_at() when formatting the value > to be returned to user space. > > Reported-by: Zeal Robot <zealci(a)zte.com.cn> > Signed-off-by: zhang songyi <zhang.songyi(a)zte.com.cn> > --- > drivers/hwtracing/coresight/coresight-stm.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > Reviewed-by: James Clark <james.clark(a)arm.com> > diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c > index 463f449cfb79..3a1b07217932 100644 > --- a/drivers/hwtracing/coresight/coresight-stm.c > +++ b/drivers/hwtracing/coresight/coresight-stm.c > @@ -466,7 +466,7 @@ static ssize_t hwevent_enable_show(struct device *dev, > struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent); > unsigned long val = drvdata->stmheer; > > - return scnprintf(buf, PAGE_SIZE, "%#lx\n", val); > + return sysfs_emit(buf, "%#lx\n", val); > } > > static ssize_t hwevent_enable_store(struct device *dev, > @@ -495,7 +495,7 @@ static ssize_t hwevent_select_show(struct device *dev, > struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent); > unsigned long val = drvdata->stmhebsr; > > - return scnprintf(buf, PAGE_SIZE, "%#lx\n", val); > + return sysfs_emit(buf, "%#lx\n", val); > } > > static ssize_t hwevent_select_store(struct device *dev, > @@ -530,7 +530,7 @@ static ssize_t port_select_show(struct device *dev, > spin_unlock(&drvdata->spinlock); > } > > - return scnprintf(buf, PAGE_SIZE, "%#lx\n", val); > + return sysfs_emit(buf, "%#lx\n", val); > } > > static ssize_t port_select_store(struct device *dev, > @@ -577,7 +577,7 @@ static ssize_t port_enable_show(struct device *dev, > spin_unlock(&drvdata->spinlock); > } > > - return scnprintf(buf, PAGE_SIZE, "%#lx\n", val); > + return sysfs_emit(buf, "%#lx\n", val); > } > > static ssize_t port_enable_store(struct device *dev,

3 years, 1 month

[PATCH v2 0/1] arm64: defconfig: Add Coresight as module

by James Clark

I'm still leaving out CONFIG_CORESIGHT_SOURCE_ETM4X because it depends on the outcome of the investigation into CONFIG_PID_IN_CONTEXTIDR, but I think we should enable these ones for now and start getting some of the benefits sooner. Changes since v1: * Remove CONFIG_CORESIGHT_CTI_INTEGRATION_REGS=y which shouldn't be enabled by default ----- As suggested by Catalin here's the change to add Coresight to defconfig. Unfortunately I don't think we should add CONFIG_CORESIGHT_SOURCE_ETM4X which builds a few files until [1] is merged because of the overhead of CONFIG_PID_IN_CONTEXTIDR. [1]: https://lore.kernel.org/lkml/20211021134530.206216-1-leo.yan@linaro.org/T/ applies to arm64/for-next/core (e99db032d186) James Clark (1): arm64: defconfig: Add Coresight as module arch/arm64/configs/defconfig | 8 ++++++++ 1 file changed, 8 insertions(+) -- 2.28.0

3 years, 1 month

Re: [PATCH 0/1] arm64: defconfig: Add Coresight as module

by James Clark

On 22/09/2022 11:52, Catalin Marinas wrote: > On Thu, Sep 22, 2022 at 10:34:45AM +0100, James Clark wrote: >> On 21/09/2022 16:08, Catalin Marinas wrote: >>> 2. Always on CONFIG_PID_IN_CONTEXTIDR (we might as well remove the >>> Kconfig entry). This would write the root pid namespace value >>> (task_pid_nr()). >> >> If we're not worried about the overhead after all, this would be the >> easiest solution. And then SPE or Coresight already decide whether they >> want to use the value or not, so no further changes are needed. >> >> From Leo's patch there is a table that shows a 1% overhead with it >> enabled permanently, and I've heard a figure like that mentioned before. >> So I could also resurrect that patch to use static keys? Although it's a >> bit more complicated, that would be my preference. And then we can have >> that mode always on. > > I don't think we should bother with static keys, just always enable it > but try to reduce/group the ISBs from all the functions called on the > __switch_to() path. We may actually get a speed-up. > Ok thanks I will take a look at this

3 years, 1 month

Re: [PATCH 0/1] arm64: defconfig: Add Coresight as module

by James Clark

On 21/09/2022 16:08, Catalin Marinas wrote: > On Wed, Sep 21, 2022 at 03:05:34PM +0100, James Clark wrote: >> As suggested by Catalin here's the change to add Coresight to defconfig. >> >> Unfortunately I don't think we should add CONFIG_CORESIGHT_SOURCE_ETM4X >> which builds a few files until [1] is merged because of the overhead >> of CONFIG_PID_IN_CONTEXTIDR. >> >> [1]: https://lore.kernel.org/lkml/20211021134530.206216-1-leo.yan@linaro.org/T/ > > I thought the overhead wasn't the problem, it's mostly negligible. We > can probably save a few more cycles on the __switch_to() path by > replacing several isb()s in those functions with a single one just > before cpu_switch_to(). > > IIRC the issue is that unless a process runs in the root pid namespace, > the actual pid written to contextidr is meaningless. This is true, and Leo has recently disabled it in that scenario in aab473867fed. > > Now that you reminded me of that thread, I see three options (sorry, not > entirely related to the defconfig updates): > > 1. Remove CONFIG_PID_IN_CONTEXTIDR and corresponding code completely, > find other events to correlate the task with the trace. Unfortunately when tracing per core we would need kernel timestamps in the trace to correlate to the switch records. At the moment Coresight is using a different clock source so it's not possible and we're still using the context ID to correlate samples. With FEAT_TRF in v8.4 it will be possible to do this and we've started working towards that here: 0f00b223ea22. But we'd still have to support older hardware too, so CONFIG_PID_IN_CONTEXTIDR can't be removed completely. For SPE it's not required because we already have the right timestamps in the samples and we've added support for no context IDs in the decoder here: 27d113cfe892 > > 2. Always on CONFIG_PID_IN_CONTEXTIDR (we might as well remove the > Kconfig entry). This would write the root pid namespace value > (task_pid_nr()). If we're not worried about the overhead after all, this would be the easiest solution. And then SPE or Coresight already decide whether they want to use the value or not, so no further changes are needed. From Leo's patch there is a table that shows a 1% overhead with it enabled permanently, and I've heard a figure like that mentioned before. So I could also resurrect that patch to use static keys? Although it's a bit more complicated, that would be my preference. And then we can have that mode always on. > > 3. Similar to (2) but instead write task_pid_nr_ns(). An alternative > here is to write -1 if the task is not in the root pid namespace. > > Strong preference for (1). >

3 years, 1 month

Re: [PATCH 1/1] arm64: defconfig: Add Coresight as module

by James Clark

On 21/09/2022 17:46, Mathieu Poirier wrote: > On Wed, Sep 21, 2022 at 04:26:59PM +0100, Mark Brown wrote: >> On Wed, Sep 21, 2022 at 03:05:35PM +0100, James Clark wrote: >> >>> +CONFIG_CORESIGHT_CTI=m >>> +CONFIG_CORESIGHT_CTI_INTEGRATION_REGS=y >> > > I agree - integration registers should not be enabled by default. > >> Do we want this turned on by default? According to the >> description it's a bit dangerous and it's exposed via sysfs >> rather than debugfs. > > Should I disable just CONFIG_CORESIGHT_CTI_INTEGRATION_REGS or CONFIG_CORESIGHT_CTI as well? There are other writable registers exposed via sysfs outside of these two options, so I wanted to check if it's just the integration registers that are the issue.

3 years, 1 month

[PATCH 0/1] arm64: defconfig: Add Coresight as module

by James Clark

As suggested by Catalin here's the change to add Coresight to defconfig. Unfortunately I don't think we should add CONFIG_CORESIGHT_SOURCE_ETM4X which builds a few files until [1] is merged because of the overhead of CONFIG_PID_IN_CONTEXTIDR. [1]: https://lore.kernel.org/lkml/20211021134530.206216-1-leo.yan@linaro.org/T/ James Clark (1): arm64: defconfig: Add Coresight as module arch/arm64/configs/defconfig | 9 +++++++++ 1 file changed, 9 insertions(+) -- 2.28.0

3 years, 1 month

Re: coresight-etm4x-core.c:969:26: error: 'ID_AA64DFR0_TRACEVER_SHIFT' undeclared

by James Clark

On 20/09/2022 12:39, Naresh Kamboju wrote: > Following build warnings / errors noticed while building arm64 coresight > on linux next-20220919 and next-20220920. Fix is here: https://lists.linaro.org/archives/list/coresight@lists.linaro.org/thread/OS… > > Reported-by: Linux Kernel Functional Testing <lkft(a)linaro.org> > > make --silent --keep-going --jobs=8 > O=/home/tuxbuild/.cache/tuxmake/builds/1/build > CROSS_COMPILE_COMPAT=arm-linux-gnueabihf- ARCH=arm64 > CROSS_COMPILE=aarch64-linux-gnu- 'CC=sccache aarch64-linux-gnu-gcc' > 'HOSTCC=sccache gcc' > > drivers/hwtracing/coresight/coresight-etm4x-core.c: In function > 'cpu_supports_sysreg_trace': > drivers/hwtracing/coresight/coresight-etm4x-core.c:969:26: error: > 'ID_AA64DFR0_TRACEVER_SHIFT' undeclared (first use in this function); > did you mean 'ID_AA64DFR0_EL1_TraceVer_SHIFT'? > 969 | return ((dfr0 >> ID_AA64DFR0_TRACEVER_SHIFT) & 0xfUL) > 0; > | ^~~~~~~~~~~~~~~~~~~~~~~~~~ > | ID_AA64DFR0_EL1_TraceVer_SHIFT > drivers/hwtracing/coresight/coresight-etm4x-core.c:969:26: note: each > undeclared identifier is reported only once for each function it > appears in > drivers/hwtracing/coresight/coresight-etm4x-core.c: In function > 'cpu_detect_trace_filtering': > drivers/hwtracing/coresight/coresight-etm4x-core.c:1057:57: error: > 'ID_AA64DFR0_TRACE_FILT_SHIFT' undeclared (first use in this > function); did you mean 'ID_AA64PFR0_EL1_DIT_SHIFT'? > 1057 | if (!cpuid_feature_extract_unsigned_field(dfr0, > ID_AA64DFR0_TRACE_FILT_SHIFT)) > | > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ > | > ID_AA64PFR0_EL1_DIT_SHIFT > drivers/hwtracing/coresight/coresight-etm4x-core.c: In function > 'cpu_supports_sysreg_trace': > drivers/hwtracing/coresight/coresight-etm4x-core.c:970:1: error: > control reaches end of non-void function [-Werror=return-type] > 970 | } > | ^ > cc1: some warnings being treated as errors > > Regressions found on arm64: > - build-clang-13-lkftconfig > - build-gcc-11-lkftconfig-devicetree > - build-gcc-11-lkftconfig-kunit > - build-gcc-11-lkftconfig-perf > - build-gcc-11-lkftconfig-64k_page_size > - build-gcc-11-lkftconfig-debug > - build-gcc-11-lkftconfig-libgpiod > - build-gcc-11-lkftconfig-debug-kmemleak > - build-clang-14-lkftconfig > - build-clang-nightly-lkftconfig > - build-gcc-11-lkftconfig > - build-gcc-11-lkftconfig-kasan > - build-clang-12-lkftconfig > - build-gcc-11-lkftconfig-kselftest-kernel > - build-gcc-11-lkftconfig-rcutorture > - build-gcc-11-lkftconfig-armv8_features > - build-gcc-11-lkftconfig-kselftest > > Build: https://builds.tuxbuild.com/2F1cW8NpQ0Z6l9h9rfkZT5AXzqg/ > config: https://builds.tuxbuild.com/2F1cW8NpQ0Z6l9h9rfkZT5AXzqg/config > > > -- > Linaro LKFT > https://lkft.linaro.org > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel(a)lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

3 years, 1 month

[PATCH] coresight: Use new autogenerated sysreg definitions

by James Clark

Fix the build by updating registers to use the new autogenerated format. Fixes: c0357a73fa4a ("arm64/sysreg: Align field names in ID_AA64DFR0_EL1 with architecture") Signed-off-by: James Clark <james.clark(a)arm.com> --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 ++-- drivers/hwtracing/coresight/coresight-trbe.h | 3 ++- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index d39660a3e50c..80fefaba58ee 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -966,7 +966,7 @@ static inline bool cpu_supports_sysreg_trace(void) { u64 dfr0 = read_sysreg_s(SYS_ID_AA64DFR0_EL1); - return ((dfr0 >> ID_AA64DFR0_TRACEVER_SHIFT) & 0xfUL) > 0; + return ((dfr0 >> ID_AA64DFR0_EL1_TraceVer_SHIFT) & 0xfUL) > 0; } static bool etm4_init_sysreg_access(struct etmv4_drvdata *drvdata, @@ -1054,7 +1054,7 @@ static void cpu_detect_trace_filtering(struct etmv4_drvdata *drvdata) u64 trfcr; drvdata->trfcr = 0; - if (!cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_TRACE_FILT_SHIFT)) + if (!cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceFilt_SHIFT)) return; /* diff --git a/drivers/hwtracing/coresight/coresight-trbe.h b/drivers/hwtracing/coresight/coresight-trbe.h index 30e4d7db4f8e..98ff1b17ad07 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.h +++ b/drivers/hwtracing/coresight/coresight-trbe.h @@ -20,7 +20,8 @@ static inline bool is_trbe_available(void) { u64 aa64dfr0 = read_sysreg_s(SYS_ID_AA64DFR0_EL1); - unsigned int trbe = cpuid_feature_extract_unsigned_field(aa64dfr0, ID_AA64DFR0_TRBE_SHIFT); + unsigned int trbe = cpuid_feature_extract_unsigned_field(aa64dfr0, + ID_AA64DFR0_EL1_TraceBuffer_SHIFT); return trbe >= 0b0001; } -- 2.28.0

3 years, 1 month

[GIT PULL] Coresight changes for v6.1

by Suzuki K Poulose

Hi Greg, Please find the coresight self hosted trace subsystem updates for v6.1. Kindly consider pulling. Thanks Suzuki The following changes since commit 1c23f9e627a7b412978b4e852793c5e3c3efc555: Linux 6.0-rc2 (2022-08-21 17:32:54 -0700) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/coresight/linux.git tags/coresight-next-v6.1 for you to fetch changes up to 5fc1531dd771cd1481116a66f992a190e01efce6: hwtracing: hisi_ptt: Fix up for "iommu/dma: Make header private" (2022-09-12 10:12:25 -0600) ---------------------------------------------------------------- coresight: Changes for v6.1 Coresight trace subsystem updates for v6.1 includes: - Support for HiSilicon PTT trace - Coresight cleanup of sysfs accessor functions, reduced code size. - Expose coresight timestamp source for ETMv4+ - DT binding updates to include missing properties - Minor documentation, Kconfig text fixes. Signed-off-by: Suzuki K Poulose <suzuki.poulose(a)arm.com> ---------------------------------------------------------------- Christophe JAILLET (1): coresight: docs: Fix a broken reference German Gomez (2): coresight: etm4x: Expose default timestamp source in sysfs coresight: etm4x: docs: Add documentation for 'ts_source' sysfs interface James Clark (5): coresight: Remove unused function parameter coresight: Simplify sysfs accessors by using csdev_access abstraction coresight: Re-use same function for similar sysfs register accessors coresight: cti-sysfs: Re-use same functions for similar sysfs register accessors coresight: Make new csdev_access offsets unsigned Nathan Chancellor (1): coresight: cti-sysfs: Mark coresight_cti_reg_store() as __maybe_unused Randy Dunlap (1): coresight: trbe: fix Kconfig "its" grammar Rob Herring (2): dt-bindings: arm: coresight: Add 'power-domains' property dt-bindings: arm: coresight-tmc: Add 'iommu' property Stephen Rothwell (1): hwtracing: hisi_ptt: Fix up for "iommu/dma: Make header private" Yicong Yang (5): iommu/arm-smmu-v3: Make default domain type of HiSilicon PTT device to identity hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe Tune and Trace device hwtracing: hisi_ptt: Add tune function support for HiSilicon PCIe Tune and Trace device docs: trace: Add HiSilicon PTT device driver documentation MAINTAINERS: Add maintainer for HiSilicon PTT driver .../ABI/testing/sysfs-bus-coresight-devices-etm4x | 8 + Documentation/ABI/testing/sysfs-devices-hisi_ptt | 61 ++ .../bindings/arm/arm,coresight-catu.yaml | 3 + .../devicetree/bindings/arm/arm,coresight-cti.yaml | 3 + .../bindings/arm/arm,coresight-dynamic-funnel.yaml | 3 + .../arm/arm,coresight-dynamic-replicator.yaml | 3 + .../bindings/arm/arm,coresight-etb10.yaml | 3 + .../devicetree/bindings/arm/arm,coresight-etm.yaml | 3 + .../bindings/arm/arm,coresight-static-funnel.yaml | 3 + .../arm/arm,coresight-static-replicator.yaml | 3 + .../devicetree/bindings/arm/arm,coresight-stm.yaml | 3 + .../devicetree/bindings/arm/arm,coresight-tmc.yaml | 6 + .../bindings/arm/arm,coresight-tpiu.yaml | 3 + .../bindings/arm/arm,embedded-trace-extension.yaml | 3 + .../trace/coresight/coresight-cpu-debug.rst | 3 +- .../trace/coresight/coresight-etm4x-reference.rst | 14 + Documentation/trace/hisi-ptt.rst | 298 ++++++ Documentation/trace/index.rst | 1 + MAINTAINERS | 8 + arch/arm64/include/asm/sysreg.h | 1 + drivers/Makefile | 1 + drivers/hwtracing/Kconfig | 2 + drivers/hwtracing/coresight/Kconfig | 4 +- drivers/hwtracing/coresight/coresight-catu.c | 27 +- drivers/hwtracing/coresight/coresight-catu.h | 8 +- drivers/hwtracing/coresight/coresight-core.c | 28 + drivers/hwtracing/coresight/coresight-cti-sysfs.c | 213 ++-- drivers/hwtracing/coresight/coresight-etb10.c | 28 +- .../hwtracing/coresight/coresight-etm3x-sysfs.c | 34 +- .../hwtracing/coresight/coresight-etm4x-sysfs.c | 29 + drivers/hwtracing/coresight/coresight-priv.h | 72 +- drivers/hwtracing/coresight/coresight-replicator.c | 10 +- drivers/hwtracing/coresight/coresight-stm.c | 40 +- drivers/hwtracing/coresight/coresight-tmc-core.c | 48 +- drivers/hwtracing/coresight/coresight-tmc.h | 4 +- drivers/hwtracing/ptt/Kconfig | 12 + drivers/hwtracing/ptt/Makefile | 2 + drivers/hwtracing/ptt/hisi_ptt.c | 1046 ++++++++++++++++++++ drivers/hwtracing/ptt/hisi_ptt.h | 200 ++++ drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 21 + include/linux/coresight.h | 23 + 41 files changed, 1973 insertions(+), 312 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-devices-hisi_ptt create mode 100644 Documentation/trace/hisi-ptt.rst create mode 100644 drivers/hwtracing/ptt/Kconfig create mode 100644 drivers/hwtracing/ptt/Makefile create mode 100644 drivers/hwtracing/ptt/hisi_ptt.c create mode 100644 drivers/hwtracing/ptt/hisi_ptt.h

3 years, 1 month

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