CoreSight

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2722 discussions

Re: [PATCH 7/9] perf test cs-etm: Test branch history on existing samples

by James Clark

On 03/08/2026 10:06, Amir Ayupov wrote: > Add a CoreSight shell test for --itrace=L. Record timestamped ETM trace > with explicit -T sample timestamps and AUX pause/resume events, then > check that the pause samples carry both a multi-frame callchain and a > non-empty branch stack for each of the workload's two processes. > > Decode the same recording with L4 and L64 and reject any branch stack > deeper than the requested depth. > > The test skips when cs_etm is absent, when not run as root, or when the > recording turns out to lack virtual timestamps. It exercises the > timestamp-gated path and the requested-depth bound; it does not attempt > to verify that the attached history is correlated to the sample. > > Signed-off-by: Amir Ayupov <aaupov(a)fb.com> > --- > .../tests/shell/coresight/add_last_branch.sh | 175 ++++++++++++++++++ > 1 file changed, 175 insertions(+) > create mode 100755 tools/perf/tests/shell/coresight/add_last_branch.sh > > diff --git a/tools/perf/tests/shell/coresight/add_last_branch.sh b/tools/perf/tests/shell/coresight/add_last_branch.sh > new file mode 100755 > index 0000000000000..4654069ad651f > --- /dev/null > +++ b/tools/perf/tests/shell/coresight/add_last_branch.sh > @@ -0,0 +1,175 @@ > +#!/bin/bash -e > +# SPDX-License-Identifier: GPL-2.0 > +# CoreSight branch history on existing samples (exclusive) > + > +perf list pmu | grep -q 'cs_etm//' || exit 2 > + > +if [ "$(id -u)" != 0 ]; then > + echo "[Skip] No root permission" > + exit 2 > +fi Is this so you can use -C 0? It's not completely obvious what that has to do with the test. Can you not drop the -C option or use --per-thread mode with a simpler non-forking workload? I don't mind keeping it for some variety in the tests, but it should be documented. > + > +tmpdir=$(mktemp -d /tmp/perf-cs-add-last-branch.XXXXX) > + > +cleanup() > +{ > + rm -rf "$tmpdir" > + trap - EXIT TERM INT > +} > + > +# shellcheck disable=SC2317 # Called through trap. > +trap_cleanup() > +{ > + cleanup > + exit 1 > +} > +trap trap_cleanup EXIT TERM INT > + > +record_data() > +{ > + if perf record -T -o "$tmpdir/data" -C 0 \ > + -e cs_etm/aux-action=start-paused,timestamp/u \ Timestamp needs a value on newer kernels or Perf returns an error. But do you need to provide the option at all? It's on by default for per-CPU mode. > + -e cycles/aux-action=resume,period=550019/u \ > + -e cycles/aux-action=pause,period=100003,call-graph=fp/u -- \ > + taskset --cpu-list 0 perf test -w context_switch_loop 100000 \ The other Coresight tests use --workload-ctl to record less data and save some decode time. I think this test might benefit from it too. > + >/dev/null 2>"$tmpdir/stderr"; then > + return 0 > + fi > + > + echo "Failed to record ETM trace with AUX pause/resume" >&2 > + cat "$tmpdir/stderr" >&2 > + return 1 > +} > + > +decode() > +{ > + local size=$1 > + local output=$2 > + > + if perf script -i "$tmpdir/data" --itrace="L$size" \ > + -F comm,pid,tid,event,ip,brstack >"$output" \ > + 2>"$tmpdir/stderr"; then > + return 0 > + fi > + > + if grep -q "itrace=L requires virtual timestamped trace" \ > + "$tmpdir/stderr"; then > + echo "[Skip] Virtual CoreSight timestamps are not available" > + cleanup > + exit 2 > + fi > + > + cat "$tmpdir/stderr" >&2 > + return 1 > +} > + > +check_process_samples() > +{ > + local output=$1 > + local comm > + > + for comm in proc1 proc2; do > + awk -v comm="$comm" ' > + $1 == comm && /cycles\/aux-action=pause/ { > + in_sample = 1 > + next > + } > + !NF { > + in_sample = 0 > + next > + } > + in_sample && /0x[[:xdigit:]]+\/0x[[:xdigit:]]+\// { > + found = 1 > + } > + END { exit !found } > + ' "$output" || { > + echo "No pause-event branch stack found for $comm" >&2 > + return 1 > + } > + done > +} > + > +check_callchains() > +{ > + local output="$tmpdir/script-callchain" > + > + perf script -i "$tmpdir/data" -F comm,event,ip >"$output" 2>/dev/null > + > + awk ' > + /cycles\/aux-action=pause/ { > + in_sample = 1 > + frames = 0 > + next > + } > + !NF { > + if (in_sample && frames >= 2) > + found = 1 > + in_sample = 0 > + next > + } > + in_sample && /^[[:space:]]+[[:xdigit:]]+([[:space:]]|$)/ { > + frames++ > + } > + END { > + if (in_sample && frames >= 2) > + found = 1 > + exit !found > + } > + ' "$output" || { > + echo "No multi-frame pause-event callchain found" >&2 > + return 1 > + } Can you add some example output in the test saying what these awks are looking for. It failed for me but I wasn't sure why. I've attached my script-callchain file if that helps. > +} > + > +check_branch_stacks() > +{ > + local output=$1 > + local max_entries=$2 > + > + local ret > + > + if awk -v max="$max_entries" ' > + /0x[[:xdigit:]]+\/0x[[:xdigit:]]+\// { > + entries = 0 > + for (i = 1; i <= NF; i++) > + if ($i ~ /^0x[[:xdigit:]]+\/0x[[:xdigit:]]+\//) > + entries++ > + if (entries) > + found = 1 > + if (entries > max) { > + status = 2 > + exit > + } > + } > + END { > + if (status) > + exit status > + if (!found) > + exit 1 > + } > + ' "$output"; then > + return 0 > + else > + ret=$? > + fi > + > + case $ret in > + 1) echo "No ETM branch stacks found" >&2 ;; > + 2) echo "Branch stack exceeds requested L$max_entries depth" >&2 ;; > + esac > + return 1 > +} > + > +record_data > +check_callchains > + > +decode 4 "$tmpdir/script-l4" > +check_process_samples "$tmpdir/script-l4" > +check_branch_stacks "$tmpdir/script-l4" 4 > + > +decode 64 "$tmpdir/script-l64" > +check_process_samples "$tmpdir/script-l64" > +check_branch_stacks "$tmpdir/script-l64" 64 > + > +cleanup > +exit 0

3 months

Re: [PATCH 0/9] perf cs-etm: Add branch history to existing samples

by James Clark

On 03/08/2026 10:01, Amir Ayupov wrote: > This series implements --itrace=L for Arm CoreSight ETM: decoded branch Hi Amir, How did you send this? The cover letter seems to be on a different thread to the patches. > history is attached to the PMU samples already present in the recording, > rather than to synthesised instruction samples. > > The motivating use case is context-sensitive PGO, which wants a callchain > and a branch stack describing the same point in time. Recording a cycles > event with call-graph=fp and aux-action=pause supplies the callchain, and > the ETM trace leading up to that sample supplies the branch stack, without > having to trace a long-running process continuously. > > Intel PT has had this since commit f0a0251cee80 ("perf intel-pt: Add > support for synthesizing branch stacks for regular events"), so this > deliberately follows intel-pt: the same --itrace=L option and the same > thread_stack__br_sample_late() call. > > Patches 1 to 4 are independent fixes and infrastructure the feature needs: > > 1 makes an inconsistent HEADER_GROUP_DESC non-fatal. AUX recordings > using aux-action pause/resume produce a group descriptor the strict > reader rejects, which makes an otherwise readable perf.data > unreadable, so without this the recipe in patch 9 cannot be decoded > at all. Useful on its own. > 2 reports hw_idx as -1 rather than 0 in reconstructed branch stacks, > since they have no hardware index. > 3 bounds a wrapped memcpy in thread_stack__br_sample(). Latent today, > reachable once a caller keeps a ring larger than the requested output > depth. > 4 adds a dlfilter that drops samples with an empty branch stack. > > Patch 5 is a no-functional-change refactor splitting > cs_etm__process_timestamped_queues() into its three parts. Heap seeding > moves to cs_etm__update_queues(), gated on queues.new_data and mirroring > intel_pt_update_queues(); the end-of-session flush moves to > cs_etm__flush_timestamped_queues(); and the decode loop is left on its own > so patch 6 can drive it once per sample. Neither seeding nor flushing can > be repeated, which is why they have to come out first. The moved code is > unchanged, so both loops appear as context in the diff. > > Patch 6 is the feature and patch 7 adds a shell test. > > Patch 8 is where review attention is most useful. --itrace=L attaches > whatever the thread stack holds when a sample is processed. With a duty > cycled trace most samples fire while the trace is off; they have nothing > newly decoded, but the thread stack still holds the previous window, so > they were being given branches that ran an arbitrary amount of time > earlier. On a 12 s capture with pause period 100003 and resume period > 8350251, of 335291 samples that received branch history only 3371 were > backed by trace decoded for that sample. > > A trace window belongs to exactly one sample, and with AUX pause and > resume the sample is what stops the trace, so the pairing is one to one by What happens when aux-pause isn't used and there isn't a 1:1 pairing? There is a lot of description of that which implies that it doesn't work if there isn't. But as far as I can tell it works just as well by using the timestamps? > construction. Patch 8 therefore takes the branch history when attaching it > instead of copying it, and a later sample with nothing newly decoded finds > an empty branch stack, which the dlfilter removes. > thread_stack__br_sample() is unchanged, so lowercase --itrace=l keeps the > overlapping branch stacks it produces today. > > Patch 9 documents the workflow. > > Because the sample is what stops the trace, the history attached to it > lines up well with the callchain: on a brstack capture the leaf of the > callchain matched the function containing the newest branch stack entry's > target for 93.5% of attached samples. The residual comes from the decode > loop stopping on interpolated timestamps, so a few branches that ran just > after the sample can still be included. Trimming those with the sample ip > raises it to 96.8%, but that matters far more for free-running ETM > strobing than for pause and resume, so I have left it out of this series > and will send it separately. > > Patch 8 could be squashed into patch 6, since patch 6 on its own produces > mostly stale history. I kept them apart so the decode mechanism and the > attachment policy can be reviewed separately, but I am happy to fold them. > > Testing > ------- > > Built with: > > make -C tools/perf NO_LIBELF=1 NO_LIBTRACEEVENT=1 CORESIGHT=1 > > Every patch builds individually. checkpatch reports only "does MAINTAINERS > need updating?" for the two new files and "quoted string split across > lines" for the dlfilter description string, which matches how > dlfilter-show-cycles.c already writes it. > > Tested on Arm Neoverse V2 with CoreSight ETM: > > - perf test "CoreSight branch history on existing samples": Ok, 3 for 3 > - captures from 5 MiB to 2.5 GiB decoded with --itrace=L64, no decode > errors > - the other CoreSight tests are unchanged by this series; four of them > fail identically at the base commit on this machine Can you report or investigate these failures please. None of the tests should be failing on TRBE hardware, at least on the latest perf-tools-next branch. You can try applying "[PATCH 00/14] perf cs-etm: Per-thread mode fixes and snapshot wrap support" to be sure, but I don't think that fixes any current failures. > > Amir Ayupov (9): > perf header: Tolerate inconsistent HEADER_GROUP_DESC > perf thread-stack: Report branch stack hw_idx as not available > perf thread-stack: Bound wrapped branch stack copy > perf dlfilter: Add non-empty branch stack filter > perf cs-etm: Split up cs_etm__process_timestamped_queues() > perf cs-etm: Add branch history to existing samples > perf test cs-etm: Test branch history on existing samples > perf cs-etm: Consume branch history when attaching it to a sample > Documentation: coresight: Document context-sensitive PGO workflow > > .../trace/coresight/coresight-perf.rst | 62 +++++ > tools/perf/Makefile.perf | 1 + > .../dlfilters/dlfilter-nonempty-brstack.c | 26 ++ > .../tests/shell/coresight/add_last_branch.sh | 175 +++++++++++++ > tools/perf/util/cs-etm.c | 242 ++++++++++++++++-- > tools/perf/util/header.c | 42 ++- > tools/perf/util/thread-stack.c | 21 +- > tools/perf/util/thread-stack.h | 1 + > 8 files changed, 544 insertions(+), 26 deletions(-) > create mode 100644 tools/perf/dlfilters/dlfilter-nonempty-brstack.c > create mode 100755 tools/perf/tests/shell/coresight/add_last_branch.sh > > > base-commit: da85966dfd23a3b03e00ee3bce6ad301f0a2b229

3 months

Re: [PATCH 7/9] perf test cs-etm: Test branch history on existing samples

by James Clark

3 months

Re: [PATCH] coresight: configfs: restrict address parameter value to root

by Leo Yan

On Wed, Aug 12, 2026 at 05:13:14PM +0800, Junrui Luo via B4 Relay wrote: > Mark parameters that can hold a kernel address, and give those a > config_item_type whose 'value' attribute is 0600. Parameters holding > plain numbers, such as the strobing 'window' and 'period' counts, keep > the existing mode. Thanks for reporting the issue. The patch seems overly complex to me. I'd suggest: --- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c @@ -281,9 +281,16 @@ static ssize_t cscfg_param_value_show(struct config_item *item, char *page) { struct cscfg_fs_param *param_item = container_of(to_config_group(item), struct cscfg_fs_param, group); - u64 value = param_item->feat_desc->params_desc[param_item->param_idx].value; - - return scnprintf(page, PAGE_SIZE, "0x%llx\n", value); + struct cscfg_parameter_desc *param_desc = + param_item->feat_desc->params_desc + param_item->param_idx; + const char *name = param_desc->name; + u64 value = param_desc->value; + + /* The kernel address should print with the "%pK" specifier */ + if (!strncmp(name, "address")) + return scnprintf(page, PAGE_SIZE, "0x%pK\n", value); + else + return scnprintf(page, PAGE_SIZE, "0x%llx\n", value); } We can add a flag (e.g., is_addr) in cscfg_parameter_desc to indicate a parameter presents an address. Since currently only pstop's "address" parameter has this issue, adding a general flag can be deferred until it is actually needed. Thanks, Leo

3 months

Re: [PATCH 2/9] perf thread-stack: Report branch stack hw_idx as not available

by James Clark

On 03/08/2026 10:06, Amir Ayupov wrote: > thread_stack__br_sample() and thread_stack__br_sample_late() fill a > caller-supplied branch_stack that is typically allocated with zalloc(), > leaving hw_idx as 0. Zero is a valid hardware index, so consumers that > honour PERF_SAMPLE_BRANCH_HW_INDEX see a reconstructed branch stack > claiming to start at LBR TOS entry 0. > > These branch stacks are reconstructed from instruction trace and have no > hardware index at all. Set hw_idx to -1ULL, which is the established way > to say "not available" and matches what intel-pt and cs-etm already put > in the branch stacks they synthesise directly. > This fix makes sense in case someone doesn't overwrite it, but I think "matches what cs-etm already puts in the branch stacks" isn't quite right. Based on the hw_id docs, cs-etm should be setting 0 shouldn't it? * For the architectures whose raw branch records are * already stored in age order, the hw_idx should be 0. -1 "unknown" isn't accurate as we do know what the order is because we generate them in order. If anyone is reading the field 0 is much more useful than -1. Can we change cs_etm__synth_branch_sample() to 0 and update this commit message to not say that -1 is right for cs-etm? > Signed-off-by: Amir Ayupov <aaupov(a)fb.com> > --- > tools/perf/util/thread-stack.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c > index c5ce741b07446..1a3dffa83bde2 100644 > --- a/tools/perf/util/thread-stack.c > +++ b/tools/perf/util/thread-stack.c > @@ -624,6 +624,7 @@ void thread_stack__br_sample(struct thread *thread, int cpu, > unsigned int nr; > > dst->nr = 0; > + dst->hw_idx = -1ULL; > > if (!ts) > return; > @@ -686,6 +687,7 @@ void thread_stack__br_sample_late(struct thread *thread, int cpu, > bool start = false; > > dst->nr = 0; > + dst->hw_idx = -1ULL; > > if (!ts) > return;

3 months

[PATCH 0/2] perf/arm: Prefer large AUX mappings for CoreSight and SPE

by Leo Yan

Since the commit: 18049c8cff9 ("perf/aux: Allocate non-contiguous AUX pages by default") it changed the AUX buffer allocator to allocate AUX pages page-by-page (order=0) unless a PMU explicitly asks for contiguous allocations via the capability flag PERF_PMU_CAP_AUX_PREFER_LARGE. The goal was to make AUX allocation more memory-friendly by default, because not all PMUs require physically contiguous AUX pages and large contiguous allocations can contribute to fragmentation on long-running systems. However, Arm SPE and CoreSight/TRBE rely on page-table translation when writing trace data to memory. With page-by-page AUX allocation, a large AUX buffer is mapped with many small mappings. This increases TLB pressure, in practice this can increase trace-buffer latency due to table translation walks (TTW) and contribute to trace discontinuities. This series restores large AUX allocation for Arm CoreSight and SPE by setting PERF_PMU_CAP_AUX_PREFER_LARGE. This is intended to work together with the mm large-mapping series [1]. That series allows vmap() to map physically contiguous pages with larger granules. With this series, perf first tries larger-order AUX allocations, and the vmap() code can then create larger mappings for the contiguous chunks. The fragmentation concern from commit 18049c8cff9c should not block this opt-in. PERF_PMU_CAP_AUX_PREFER_LARGE is a preference, not a hard requirement. The AUX allocator already falls back to smaller orders when a high-order allocation fails. So this series gives Arm trace PMUs the performance benefit when large chunks are available. The comparison below uses a baseline that already includes the mm large-mapping series [1]. "Baseline" means that the mm series is applied but this Arm PMU series is not. "Large AUX" means the same kernel plus this series. Some configurations to mitigate noise during test: 1) The tests were run with CPU10 isolated with the kernel parameter "isolcpus=10". 2) CPU10 was used as the traced CPU, the PMU counter CPU, and the workload CPU. The perf control tasks were pinned to CPU2 so that they did not add extra work on CPU10. 3) Each test was run for 10 iterations, and the tables report the average counter values across those runs. The results show that using larger AUX mappings reduces the TLB pressure. This is mainly visible in the refill events: CoreSight/TRBE shows a large drop in l2d_tlb_refill and a smaller reduction in l1d_tlb_refill, while SPE also reduces l2d_tlb_refill. The dtlb_walk event also drops in both tests, which shows fewer data TLB walks after the AUX buffer can be mapped with larger granules. ETM sparse branch delay (cs_etm, AUX 1GB) taskset -c 2 perf stat -C 10 -e cycles:u,instructions:u,dtlb_walk:u,l1d_tlb:u,l1d_tlb_refill:u,l2d_tlb_refill:u \ -- taskset -c 2 perf record -C 10 -m ,1G -e cs_etm// \ -- taskset -c 10 ./sparse_branch_delay.elf | | Baseline | Large map | | | | Metric | Avg. | Avg. | Delta | Change | |----------------+-----------+-----------+------------+---------| | dtlb_walk | 72.8 | 63.9 | -8.9 | -12.23% | | l1d_tlb | 7,434.4 | 1,982.2 | -5,452.2 | -73.34% | | l1d_tlb_refill | 163.7 | 148.2 | -15.5 | -9.47% | | l2d_tlb_refill | 161,884.9 | 513.1 | -161,371.8 | -99.68% | SPE dd memory copy (arm_spe, AUX 512MB) taskset -c 2 perf stat -C 10 -e cycles:u,instructions:u,dtlb_walk:u,l1d_tlb:u,l1d_tlb_refill:u,l2d_tlb_refill:u \ -- taskset -c 2 perf record -C 10 -m ,512M -e arm_spe_0/ts_enable=1,pa_enable=1,period=64,min_latency=0/ \ -- taskset -c 10 dd if=/dev/zero of=/dev/shm/dd_mem_test bs=1M count=1024 status=progress | | Baseline | Large map | | | | Metric | Avg. | Avg. | Delta | Change | |----------------+-----------+-----------+------------+---------| | dtlb_walk | 1,760.2 | 1,387.9 | -372.3 | -21.15% | | l1d_tlb | 257,312.4 | 251,460.9 | -5,851.5 | -2.27% | | l1d_tlb_refill | 15,921.9 | 15,933.6 | 11.7 | +0.07% | | l2d_tlb_refill | 4,285.0 | 2,796.5 | -1,488.5 | -34.74% | Note that after setting PREFER_LARGE for CoreSight and SPE, the existing AUX trace drivers either prefer large pages or, in the case of Intel BTS/PT, use the stronger AUX_NO_SG constraint. We can refactor this later by either dropping PREFER_LARGE entirely or reversing the flag if a driver needs discrete pages. For now, keep PREFER_LARGE to preserve flexibility in the allocation policy. [1] https://lore.kernel.org/linux-mm/20260715120813.3609949-1-jiangwen6@xiaomi.… Signed-off-by: Leo Yan <leo.yan(a)arm.com> --- Dev Jain (1): coresight: perf: Prefer large AUX mappings Leo Yan (1): perf: arm_spe: Prefer large AUX mappings drivers/hwtracing/coresight/coresight-etm-perf.c | 3 ++- drivers/perf/arm_spe_pmu.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) --- base-commit: db2ddb87143519e20a95aa36c60b36107b736a58 change-id: 20260717-perf_aux_trace_large_granule-d9b30cc14b5a Best regards, -- Leo Yan <leo.yan(a)arm.com>

3 months

[GIT PULL] coresight: Updates for Linux v7.3

by Suzuki K Poulose

Hi Greg Please find this pull request for CoreSight subsystem targeting v7.3. Almost all of them are fixes to the existing code, along with a MAINTAINERS update for HiSilicon PTT driver. Kindly pull Suzuki The following changes since commit 8cdeaa50eae8dad34885515f62559ee83e7e8dda: Linux 7.2-rc2 (2026-07-05 14:44:06 -1000) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/coresight/linux.git tags/coresight-next-v7.3 for you to fetch changes up to 9e3604d7369cfc0110100eb1a0acab1865ee2d18: coresight: etm4x: remove redundant fields in etmv4_save_state (2026-08-07 10:45:11 +0100) ---------------------------------------------------------------- coresight: Updates for Linux v7.3 This is relatively smaller update for CoreSight/hwtracing subsystem updates. - MAINTAINERS update for HiSilicon PCI Trace & Tune drivers - Minor fixes to hisi_ptt driver - Various fixes to the coresight etm4x dirvers Signed-off-by: Suzuki K Poulose <suzuki.poulose(a)arm.com> ---------------------------------------------------------------- Jonathan Cameron (1): MAINTAINERS: Update HiSilicon PCI Trace and Tune maintainer Kuan-Wei Chiu (1): coresight: etm3x: Fix cntr_val_show() to match cntr_val_store() behavior Sanman Pradhan (2): hwtracing: hisi_ptt: Propagate DMA reset timeout in trace_start() hwtracing: hisi_ptt: Remove unnecessary trace buffer zeroing in trace_start() Yeoreum Yun (5): coresight: etm4x: fix wrong check of etm4x_sspcicrn_present() coresight: etm4x: fix underflow for usage of (nrseqstate - 1) coresight: etm4x: fix leaked trace id coresight: etm4x: missing cscfg_csdev_disable_active_config() in perf enable coresight: etm4x: remove redundant fields in etmv4_save_state MAINTAINERS | 3 +- .../hwtracing/coresight/coresight-etm3x-sysfs.c | 15 ++---- drivers/hwtracing/coresight/coresight-etm4x-cfg.c | 2 +- drivers/hwtracing/coresight/coresight-etm4x-core.c | 59 +++++++++++++--------- .../hwtracing/coresight/coresight-etm4x-sysfs.c | 6 ++- drivers/hwtracing/coresight/coresight-etm4x.h | 12 ++--- drivers/hwtracing/ptt/hisi_ptt.c | 25 ++++----- 7 files changed, 63 insertions(+), 59 deletions(-)

3 months, 1 week

Re: [PATCH v1] coresight: Check runtime PM resume result

by Anshuman Khandual

On 03/08/26 4:55 AM, Yuho Choi wrote: > coresight_get_ref() ignores the return value of pm_runtime_get_sync() > and reports success even when runtime resume fails. A path is then built > and the CoreSight device may be accessed while it remains powered off. > > Use pm_runtime_resume_and_get() so a failed resume is reported and its > runtime PM usage reference is rolled back. Drop the module and device > references acquired before the resume attempt when it fails. > > Fixes: 5da5325fa856 ("coresight: moving PM runtime operations to core framework") > Signed-off-by: Yuho Choi <dbgh9129(a)gmail.com> > --- Should 'Fixes:' be tagging the following commit - which had introduced coresight_get_ref() unconditionally calling pm_runtime_get_sync() ? 32b0707a4182 ("coresight: Add try_get_module() in coresight_grab_device()") > drivers/hwtracing/coresight/coresight-core.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c > index 6d65c43d574f..77d05b360484 100644 > --- a/drivers/hwtracing/coresight/coresight-core.c > +++ b/drivers/hwtracing/coresight/coresight-core.c > @@ -843,7 +843,11 @@ static bool coresight_get_ref(struct coresight_device *csdev) > goto err_module; > > /* Make sure the device is powered on */ > - pm_runtime_get_sync(parent); > + if (pm_runtime_resume_and_get(parent) < 0) { > + module_put(drv->owner); > + goto err_module; > + } > + > return true; > > err_module:

3 months, 1 week

Re: [PATCH v3] coresight: coresight.h: add '*' to kernel-doc lines

by Anshuman Khandual

On 20/07/26 3:54 AM, Randy Dunlap wrote: > kernel-doc reports 2 (kernel-doc) lines in coresight.h that don't have > a beginning '*' in them, so fix these lines. > > Also convert struct coresight_trace_id_map to kernel-doc format to > remove another warning. > > Warning: include/linux/coresight.h:173 bad line: > connected to @src_port. NULL until the device is created > Warning: include/linux/coresight.h:177 bad line: > needs to be filtered. > Warning: include/linux/coresight.h:236 This comment starts with '/**', > but isn't a kernel-doc comment. > > Fixes: ec9903d6cc34 ("coresight: Add support for trace filtering by source") > Fixes: d49c9cf15f89 ("coresight: Rename connection members to make the direction explicit") > Signed-off-by: Randy Dunlap <rdunlap(a)infradead.org> > --- > v2: rebase & resend > v3: rebase & resend > > Cc: James Clark <james.clark(a)arm.com> > Cc: Tao Zhang <quic_taozha(a)quicinc.com> > Cc: Suzuki K Poulose <suzuki.poulose(a)arm.com> > Cc: coresight(a)lists.linaro.org > Cc: Danilo Krummrich <dakr(a)kernel.org> > Cc: Mike Leach <mike.leach(a)arm.com> > Cc: Leo Yan <leo.yan(a)arm.com> > Cc: linux-arm-kernel(a)lists.infradead.org > --- > include/linux/coresight.h | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > --- linux-next-20260717.orig/include/linux/coresight.h > +++ linux-next-20260717/include/linux/coresight.h > @@ -177,11 +177,11 @@ struct coresight_desc { > * @dest_port: destination's input port number @src_port is connected to. > * @dest_fwnode: destination component's fwnode handle. > * @dest_dev: a @coresight_device representation of the component > - connected to @src_port. NULL until the device is created > + * connected to @src_port. NULL until the device is created > * @link: Representation of the connection as a sysfs link. > * @filter_src_fwnode: filter source component's fwnode handle. > * @filter_src_dev: a @coresight_device representation of the component that > - needs to be filtered. > + * needs to be filtered. > * > * The full connection structure looks like this, where in_conns store > * references to same connection as the source device's out_conns. > @@ -234,7 +234,7 @@ struct coresight_sysfs_link { > #define CORESIGHT_TRACE_IDS_MAX 128 > > /** > - * Trace ID map. > + * struct coresight_trace_id_map - Trace ID map. > * > * @used_ids: Bitmap to register available (bit = 0) and in use (bit = 1) IDs. > * Initialised so that the reserved IDs are permanently marked as > But still there are more warnings left in the documentation file even after the patch applied. Should they be fixed as well ? ./scripts/kernel-doc -none include/linux/coresight.h Warning: include/linux/coresight.h:216 struct member 'src_dev' not described in 'coresight_connection' Warning: include/linux/coresight.h:216 struct member 'src_refcnt' not described in 'coresight_connection' Warning: include/linux/coresight.h:216 struct member 'dest_refcnt' not described in 'coresight_connection' Warning: include/linux/coresight.h:248 struct member 'cpu_map' not described in 'coresight_trace_id_map' Warning: include/linux/coresight.h:248 struct member 'lock' not described in 'coresight_trace_id_map' Warning: include/linux/coresight.h:312 struct member 'perf_sink_id_map' not described in 'coresight_device' Warning: include/linux/coresight.h:216 struct member 'src_dev' not described in 'coresight_connection' Warning: include/linux/coresight.h:216 struct member 'src_refcnt' not described in 'coresight_connection' Warning: include/linux/coresight.h:216 struct member 'dest_refcnt' not described in 'coresight_connection' Warning: include/linux/coresight.h:248 struct member 'cpu_map' not described in 'coresight_trace_id_map' Warning: include/linux/coresight.h:248 struct member 'lock' not described in 'coresight_trace_id_map' Warning: include/linux/coresight.h:312 struct member 'perf_sink_id_map' not described in 'coresight_device'

3 months, 2 weeks

[PATCH v8 00/13] fix several inconsistencies with sysfs configuration in etmX

by Yeoreum Yun

The current ETMx configuration via sysfs can lead to the following inconsistencies: - If a configuration is modified via sysfs while a perf session is active, the running configuration may differ between before a sched-out and after a subsequent sched-in. - If a perf session and sysfs session tries to enable concurrently, configuration from configfs could be corrupted (etm4). - There is chance to corrupt drvdata->config if perf session tries to enabled among handling cscfg_csdev_disable_active_config() in etm4_disable_sysfs() (etm4). To resolve these inconsistencies, the configuration should be separated into: - active_config, which is applied configuration for the current session - config, which stores the settings configured via sysfs. and apply configuration from configfs after taking a mode. Also, This patch set includes some small fixes: - missing trace id release in etm4x. - underflow issue for nrseqstate. - wrong check in etm4x_sspcicrn_present(). - missing call of cscfg_csdev_disable_active_config() This patch based on coresight tree's next Patch History ============= from v7 to v8: - accept @Leo Yan' suggestion to handle error. - small minor fixes following @Suzuki' suggestion. - https://lore.kernel.org/all/20260519154812.254884-1-yeoreum.yun@arm.com/ from v6 to v7: - rebase on coresight/next - add ETM_MAX_SEQ_TRANSITIONS define - remove redundant patch relavent cpu-hotplug as coresight-pm patch merged. - https://lore.kernel.org/all/20260422132203.977549-1-yeoreum.yun@arm.com/ from v5 to v6: - fix missing of calling cscfg_csdev_disable_active_config() - add rb & fixes tags. - add ss_status field in etm4x_drvdata to expose STATUS and PENDING bits. - https://lore.kernel.org/all/20260415165528.3369607-1-yeoreum.yun@arm.com/ from v4 to v5: - add rb-tag. - fix underflow issue for nrseqstate. - fix wrong check in etm4_sspcicrn_present(). - remove redundant fields on etmv4_save_state. - rename caps->ss_status to ss_cmp. - fix wrong location of etm4_release_trace_id. - https://lore.kernel.org/all/20260413142003.3549310-1-yeoreum.yun@arm.com/ from v3 to v4: - change etm_drvdata->spinlock type to raw_spin_lock_t - remove redundant call etmX_enable_hw() with starting_cpu() callsback. - fix missing trace id release. - add missing docs. - https://lore.kernel.org/all/20260412175506.412301-1-yeoreum.yun@arm.com/ from v2 to v3: - fix build error for etm3x. - fix checkpatch warning. - https://lore.kernel.org/all/20260410074310.2693385-1-yeoreum.yun@arm.com/ from v1 to v2 - rebased to v7.0-rc7. - introduce etmX_caps structure to save etmX's capabilities. - remove ss_status from etmv4_config. - modify active_config after taking a mode (perf/sysfs). - https://lore.kernel.org/all/20260317181705.2456271-1-yeoreum.yun@arm.com/ Yeoreum Yun (13): coresight: etm4x: fix wrong check of etm4x_sspcicrn_present() coresight: etm4x: fix underflow for usage of (nrseqstate - 1) coresight: etm4x: introduce struct etm4_caps coresight: etm4x: exclude ss_status from drvdata->config coresight: etm4x: remove s_ex_level from config coresight: etm4x: remove redundant fields in etmv4_save_state coresight: etm4x: fix leaked trace id coresight: etm4x: fix inconsistencies with sysfs configuration coresight: etm4x: missing cscfg_csdev_disable_active_config() in perf enable coresight: etm3x: change drvdata->spinlock type to raw_spin_lock_t coresight: etm3x: introduce struct etm_caps coresight: etm3x: fix inconsistencies with sysfs configuration coresight: etm3x: remove redundant cpu online check on etm_enable_sysfs() drivers/hwtracing/coresight/coresight-etm.h | 46 +- .../coresight/coresight-etm3x-core.c | 96 ++-- .../coresight/coresight-etm3x-sysfs.c | 159 +++--- .../hwtracing/coresight/coresight-etm4x-cfg.c | 5 +- .../coresight/coresight-etm4x-core.c | 454 ++++++++++-------- .../coresight/coresight-etm4x-sysfs.c | 204 ++++---- drivers/hwtracing/coresight/coresight-etm4x.h | 202 ++++---- 7 files changed, 639 insertions(+), 527 deletions(-) -- LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}

3 months, 3 weeks

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