CoreSight

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[PATCH v2 0/1] Don't immediately close events that are run on invalid CPU/sink combos

by James Clark

Changes since v1: * Replace goto with return after failure to maintain original failure behaviour * Add Mathieu and Suzuki's reviewed-by tags * Repeated testing James Clark (1): coresight: Don't immediately close events that are run on invalid CPU/sink combos .../hwtracing/coresight/coresight-etm-perf.c | 29 +++++++++++++++---- 1 file changed, 23 insertions(+), 6 deletions(-) -- 2.28.0

3 years, 9 months

[PATCH] coresight: Don't immediately close events that are run on invalid CPU/sink combos

by James Clark

When a traced process runs on a CPU that can't reach the selected sink, the event will be stopped with PERF_HES_STOPPED. This means that even if the process migrates to a valid CPU, tracing will not resume. This can be reproduced (on N1SDP) by using taskset to start the process on CPU 0, and then switching it to CPU 2 (ETF 1 is only reachable from CPU 2): taskset --cpu-list 0 ./perf record -e cs_etm/@tmc_etf1/ --per-thread -- taskset --cpu-list 2 ls This produces a single 0 length AUX record, and then no more trace: 0x3c8 [0x30]: PERF_RECORD_AUX offset: 0 size: 0 flags: 0x1 [T] After the fix, the same command produces normal AUX records. The perf self test "89: Check Arm CoreSight trace data recording and synthesized samples" no longer fails intermittently. This was because the taskset in the test is after the fork, so there is a period where the task is scheduled on a random CPU rather than forced to a valid one. Specifically selecting an invalid CPU will still result in a failure to open the event because it will never produce trace: ./perf record -C 2 -e cs_etm/@tmc_etf0/ failed to mmap with 12 (Cannot allocate memory) The only scenario that has changed is if the CPU mask has a valid CPU sink combo in it. Testing ======= * Coresight self test passes consistently: ./perf test Coresight * CPU wide mode still produces trace: ./perf record -e cs_etm// -a * Invalid -C options still fail to open: ./perf record -C 2,3 -e cs_etm/@tmc_etf0/ failed to mmap with 12 (Cannot allocate memory) * Migrating a task to a valid sink/CPU now produces trace: taskset --cpu-list 0 ./perf record -e cs_etm/@tmc_etf1/ --per-thread -- taskset --cpu-list 2 ls * If the task remains on an invalid CPU, no trace is emitted: taskset --cpu-list 0 ./perf record -e cs_etm/@tmc_etf1/ --per-thread -- ls Signed-off-by: James Clark <james.clark(a)arm.com> --- .../hwtracing/coresight/coresight-etm-perf.c | 27 +++++++++++++++---- 1 file changed, 22 insertions(+), 5 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 8ebd728d3a80..79346f0f0e0b 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -452,9 +452,14 @@ static void etm_event_start(struct perf_event *event, int flags) * sink from this ETM. We can't do much in this case if * the sink was specified or hinted to the driver. For * now, simply don't record anything on this ETM. + * + * As such we pretend that everything is fine, and let + * it continue without actually tracing. The event could + * continue tracing when it moves to a CPU where it is + * reachable to a sink. */ if (!cpumask_test_cpu(cpu, &event_data->mask)) - goto fail_end_stop; + goto out; path = etm_event_cpu_path(event_data, cpu); /* We need a sink, no need to continue without one */ @@ -466,16 +471,15 @@ static void etm_event_start(struct perf_event *event, int flags) if (coresight_enable_path(path, CS_MODE_PERF, handle)) goto fail_end_stop; - /* Tell the perf core the event is alive */ - event->hw.state = 0; - /* Finally enable the tracer */ if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF)) goto fail_disable_path; +out: + /* Tell the perf core the event is alive */ + event->hw.state = 0; /* Save the event_data for this ETM */ ctxt->event_data = event_data; -out: return; fail_disable_path: @@ -517,6 +521,19 @@ static void etm_event_stop(struct perf_event *event, int mode) if (WARN_ON(!event_data)) return; + /* + * Check if this ETM was allowed to trace, as decided at + * etm_setup_aux(). If it wasn't allowed to trace, then + * nothing needs to be torn down other than outputting a + * zero sized record. + */ + if (handle->event && (mode & PERF_EF_UPDATE) && + !cpumask_test_cpu(cpu, &event_data->mask)) { + event->hw.state = PERF_HES_STOPPED; + perf_aux_output_end(handle, 0); + return; + } + if (!csdev) return; -- 2.28.0

3 years, 9 months

Re: [PATCH v2 11/17] arm64: errata: Add workaround for TSB flush failures

by Suzuki K Poulose

Hi Anshuman On 22/09/2021 08:39, Anshuman Khandual wrote: > > > On 9/21/21 7:11 PM, Suzuki K Poulose wrote: >> Arm Neoverse-N2 (#2067961) and Cortex-A710 (#2054223) suffers >> from errata, where a TSB (trace synchronization barrier) >> fails to flush the trace data completely, when executed from >> a trace prohibited region. In Linux we always execute it >> after we have moved the PE to trace prohibited region. So, >> we can apply the workaround everytime a TSB is executed. > > s/everytime/every time Ack > >> >> The work around is to issue two TSB consecutively. >> >> NOTE: This errata is defined as LOCAL_CPU_ERRATUM, implying >> that a late CPU could be blocked from booting if it is the >> first CPU that requires the workaround. This is because we >> do not allow setting a cpu_hwcaps after the SMP boot. The >> other alternative is to use "this_cpu_has_cap()" instead >> of the faster system wide check, which may be a bit of an >> overhead, given we may have to do this in nvhe KVM host >> before a guest entry. >> >> Cc: Will Deacon <will(a)kernel.org> >> Cc: Catalin Marinas <catalin.marinas(a)arm.com> >> Cc: Mathieu Poirier <mathieu.poirier(a)linaro.org> >> Cc: Mike Leach <mike.leach(a)linaro.org> >> Cc: Mark Rutland <mark.rutland(a)arm.com> >> Cc: Anshuman Khandual <anshuman.khandual(a)arm.com> >> Cc: Marc Zyngier <maz(a)kernel.org> >> Signed-off-by: Suzuki K Poulose <suzuki.poulose(a)arm.com> >> --- ... >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >> index eac4030322df..0764774e12bb 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -705,6 +705,37 @@ config ARM64_ERRATUM_2139208 >> >> If unsure, say Y. >> >> +config ARM64_WORKAROUND_TSB_FLUSH_FAILURE >> + bool >> + >> +config ARM64_ERRATUM_2054223 >> + bool "Cortex-A710: 2054223: workaround TSB instruction failing to flush trace" >> + default y >> + help >> + Enable workaround for ARM Cortex-A710 erratum 2054223 >> + >> + Affected cores may fail to flush the trace data on a TSB instruction, when >> + the PE is in trace prohibited state. This will cause losing a few bytes >> + of the trace cached. >> + >> + Workaround is to issue two TSB consecutively on affected cores. >> + >> + If unsure, say Y. >> + >> +config ARM64_ERRATUM_2067961 >> + bool "Neoverse-N2: 2067961: workaround TSB instruction failing to flush trace" >> + default y >> + help >> + Enable workaround for ARM Neoverse-N2 erratum 2067961 >> + >> + Affected cores may fail to flush the trace data on a TSB instruction, when >> + the PE is in trace prohibited state. This will cause losing a few bytes >> + of the trace cached. >> + >> + Workaround is to issue two TSB consecutively on affected cores. > > Like I had mentioned in the previous patch, these descriptions here could > be just factored out inside ARM64_WORKAROUND_TSB_FLUSH_FAILURE instead. Please see my response there. > >> + >> + If unsure, say Y. >> + >> config CAVIUM_ERRATUM_22375 >> bool "Cavium erratum 22375, 24313" >> default y >> diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h >> index 451e11e5fd23..1c5a00598458 100644 >> --- a/arch/arm64/include/asm/barrier.h >> +++ b/arch/arm64/include/asm/barrier.h >> @@ -23,7 +23,7 @@ >> #define dsb(opt) asm volatile("dsb " #opt : : : "memory") >> >> #define psb_csync() asm volatile("hint #17" : : : "memory") >> -#define tsb_csync() asm volatile("hint #18" : : : "memory") >> +#define __tsb_csync() asm volatile("hint #18" : : : "memory") >> #define csdb() asm volatile("hint #20" : : : "memory") >> >> #ifdef CONFIG_ARM64_PSEUDO_NMI >> @@ -46,6 +46,20 @@ >> #define dma_rmb() dmb(oshld) >> #define dma_wmb() dmb(oshst) >> >> + >> +#define tsb_csync() \ >> + do { \ >> + /* \ >> + * CPUs affected by Arm Erratum 2054223 or 2067961 needs \ >> + * another TSB to ensure the trace is flushed. The barriers \ >> + * don't have to be strictly back to back, as long as the \ >> + * CPU is in trace prohibited state. \ >> + */ \ >> + if (cpus_have_final_cap(ARM64_WORKAROUND_TSB_FLUSH_FAILURE)) \ >> + __tsb_csync(); \ >> + __tsb_csync(); \ >> + } while (0) >> + >> /* >> * Generate a mask for array_index__nospec() that is ~0UL when 0 <= idx < sz >> * and 0 otherwise. >> diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c >> index ccd757373f36..bdbeac75ead6 100644 >> --- a/arch/arm64/kernel/cpu_errata.c >> +++ b/arch/arm64/kernel/cpu_errata.c >> @@ -352,6 +352,18 @@ static const struct midr_range trbe_overwrite_fill_mode_cpus[] = { >> }; >> #endif /* CONFIG_ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE */ >> >> +#ifdef CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE >> +static const struct midr_range tsb_flush_fail_cpus[] = { >> +#ifdef CONFIG_ARM64_ERRATUM_2067961 >> + MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N2), >> +#endif >> +#ifdef CONFIG_ARM64_ERRATUM_2054223 >> + MIDR_ALL_VERSIONS(MIDR_CORTEX_A710), >> +#endif >> + {}, >> +}; >> +#endif /* CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE */ >> + >> const struct arm64_cpu_capabilities arm64_errata[] = { >> #ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE >> { >> @@ -558,6 +570,13 @@ const struct arm64_cpu_capabilities arm64_errata[] = { >> .type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE, >> CAP_MIDR_RANGE_LIST(trbe_overwrite_fill_mode_cpus), >> }, >> +#endif >> +#ifdef CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILRE >> + { >> + .desc = "ARM erratum 2067961 or 2054223", >> + .capability = ARM64_WORKAROUND_TSB_FLUSH_FAILURE, >> + ERRATA_MIDR_RANGE_LIST(tsb_flush_fail_cpus), >> + }, >> #endif >> { >> } >> diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps >> index 1ccb92165bd8..2102e15af43d 100644 >> --- a/arch/arm64/tools/cpucaps >> +++ b/arch/arm64/tools/cpucaps >> @@ -54,6 +54,7 @@ WORKAROUND_1463225 >> WORKAROUND_1508412 >> WORKAROUND_1542419 >> WORKAROUND_TRBE_OVERWRITE_FILL_MODE >> +WORKAROUND_TSB_FLUSH_FAILURE >> WORKAROUND_CAVIUM_23154 >> WORKAROUND_CAVIUM_27456 >> WORKAROUND_CAVIUM_30115 >> > > This adds all the required bits of these erratas in a single patch, > where as the previous work around had split all the required pieces > into multiple patches. Could we instead follow the same standard in > both the places ? We could do this for this particular erratum as the work around is within the arm64 kernel code, unlike the other ones - where the TRBE driver needs a change. So, there is a kind of dependency for the other two, which we don't in this particular case. i.e, TRBE driver needs a cpucap number to implement the work around -> The arm64 kernel must define one, which we cant advertise yet until we have a TRBE work around. Thus, they follow a 3 step model. - Define CPUCAP erratum - TRBE driver work around - Finally advertise to the user. I don't think this one needs that. Suzuki >

3 years, 9 months

Re: [PATCH v2 14/17] coresight: trbe: Make sure we have enough space

by Suzuki K Poulose

On 22/09/2021 10:58, Anshuman Khandual wrote: > > > On 9/21/21 7:11 PM, Suzuki K Poulose wrote: >> The TRBE driver makes sure that there is enough space for a meaningful >> run, otherwise pads the given space and restarts the offset calculation >> once. But there is no guarantee that we may find space or hit "no space". > > So what happens currently when it neither finds the required minimum buffer > space for a meaningful run nor does it hit the "no space" scenario ? It tries once today and assumes that it will either hit : - No space OR - Enough space which is reasonable, given the minimum space needed is a few bytes. But this may no longer be true with other erratum workaround. > >> Make sure that we repeat the step until, either : >> - We have the minimum space >> OR >> - There is NO space at all. >> >> Cc: Anshuman Khandual <anshuman.khandual(a)arm.com> >> Cc: Mathieu Poirier <mathieu.poirier(a)linaro.org> >> Cc: Mike Leach <mike.leach(a)linaro.org> >> Cc: Leo Yan <leo.yan(a)linaro.org> >> Signed-off-by: Suzuki K Poulose <suzuki.poulose(a)arm.com> >> --- >> drivers/hwtracing/coresight/coresight-trbe.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c >> index 3373f4e2183b..02f9e00e2091 100644 >> --- a/drivers/hwtracing/coresight/coresight-trbe.c >> +++ b/drivers/hwtracing/coresight/coresight-trbe.c >> @@ -451,10 +451,14 @@ static unsigned long trbe_normal_offset(struct perf_output_handle *handle) >> * If the head is too close to the limit and we don't >> * have space for a meaningful run, we rather pad it >> * and start fresh. >> + * >> + * We might have to do this more than once to make sure >> + * we have enough required space. > > OR no space at all, as explained in the commit message. > Hence this comment needs an update. > >> */ >> - if (limit && ((limit - head) < trbe_min_trace_buf_size(handle))) { >> + while (limit && ((limit - head) < trbe_min_trace_buf_size(handle))) { >> trbe_pad_buf(handle, limit - head); >> limit = __trbe_normal_offset(handle); >> + head = PERF_IDX2OFF(handle->head, buf); > > Should the loop be bound with a retry limit as well ? No. We will eventually hit No-space as we keep on padding the buffer. Suzuki

3 years, 9 months

Re: [PATCH v2 10/17] arm64: Enable workaround for TRBE overwrite in FILL mode

by Suzuki K Poulose

On 22/09/2021 08:23, Anshuman Khandual wrote: > > > On 9/21/21 7:11 PM, Suzuki K Poulose wrote: >> Now that we have the work around implmented in the TRBE >> driver, add the Kconfig entries and document the errata. >> >> Cc: Mark Rutland <mark.rutland(a)arm.com> >> Cc: Will Deacon <will(a)kernel.org> >> Cc: Catalin Marinas <catalin.marinas(a)arm.com> >> Cc: Anshuman Khandual <anshuman.khandual(a)arm.com> >> Cc: Mathieu Poirier <mathieu.poirier(a)linaro.org> >> Cc: Mike Leach <mike.leach(a)linaro.org> >> Cc: Leo Yan <leo.yan(a)linaro.org> >> Signed-off-by: Suzuki K Poulose <suzuki.poulose(a)arm.com> >> --- >> Documentation/arm64/silicon-errata.rst | 4 +++ >> arch/arm64/Kconfig | 39 ++++++++++++++++++++++++++ >> 2 files changed, 43 insertions(+) >> >> diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst >> index d410a47ffa57..2f99229d993c 100644 >> --- a/Documentation/arm64/silicon-errata.rst >> +++ b/Documentation/arm64/silicon-errata.rst >> @@ -92,12 +92,16 @@ stable kernels. >> +----------------+-----------------+-----------------+-----------------------------+ >> | ARM | Cortex-A77 | #1508412 | ARM64_ERRATUM_1508412 | >> +----------------+-----------------+-----------------+-----------------------------+ >> +| ARM | Cortex-A710 | #2119858 | ARM64_ERRATUM_2119858 | >> ++----------------+-----------------+-----------------+-----------------------------+ >> | ARM | Neoverse-N1 | #1188873,1418040| ARM64_ERRATUM_1418040 | >> +----------------+-----------------+-----------------+-----------------------------+ >> | ARM | Neoverse-N1 | #1349291 | N/A | >> +----------------+-----------------+-----------------+-----------------------------+ >> | ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 | >> +----------------+-----------------+-----------------+-----------------------------+ >> +| ARM | Neoverse-N2 | #2139208 | ARM64_ERRATUM_2139208 | >> ++----------------+-----------------+-----------------+-----------------------------+ >> | ARM | MMU-500 | #841119,826419 | N/A | >> +----------------+-----------------+-----------------+-----------------------------+ >> +----------------+-----------------+-----------------+-----------------------------+ >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >> index 077f2ec4eeb2..eac4030322df 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -666,6 +666,45 @@ config ARM64_ERRATUM_1508412 >> >> If unsure, say Y. >> >> +config ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE >> + bool >> + >> +config ARM64_ERRATUM_2119858 >> + bool "Cortex-A710: 2119858: workaround TRBE overwriting trace data in FILL mode" >> + default y >> + depends on CORESIGHT_TRBE >> + select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE >> + help >> + This option adds the workaround for ARM Cortex-A710 erratum 2119858. >> + >> + Affected Cortex-A710 cores could overwrite upto 3 cache lines of trace >> + data at the base of the buffer (ponited by TRBASER_EL1) in FILL mode in >> + the event of a WRAP event. >> + >> + Work around the issue by always making sure we move the TRBPTR_EL1 by >> + 256bytes before enabling the buffer and filling the first 256bytes of >> + the buffer with ETM ignore packets upon disabling. >> + >> + If unsure, say Y. >> + >> +config ARM64_ERRATUM_2139208 >> + bool "Neoverse-N2: 2139208: workaround TRBE overwriting trace data in FILL mode" >> + default y >> + depends on CORESIGHT_TRBE >> + select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE >> + help >> + This option adds the workaround for ARM Neoverse-N2 erratum 2139208. >> + >> + Affected Neoverse-N2 cores could overwrite upto 3 cache lines of trace >> + data at the base of the buffer (ponited by TRBASER_EL1) in FILL mode in > > s/ponited/pointed > >> + the event of a WRAP event. >> + >> + Work around the issue by always making sure we move the TRBPTR_EL1 by >> + 256bytes before enabling the buffer and filling the first 256bytes of >> + the buffer with ETM ignore packets upon disabling. >> + >> + If unsure, say Y. >> + >> config CAVIUM_ERRATUM_22375 >> bool "Cavium erratum 22375, 24313" >> default y >> > > The real errata problem description for both these erratums are exactly > the same. Rather a more generalized description should be included for > the ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE, which abstracts out the > problem and a corresponding solution that is implemented in the driver. > This should also help us reduce current redundancy. > The issue is what a user wants to see. A user who wants to configure the kernel specifically for a given CPU (think embedded systems), they would want to hand pick the errata for the particular CPU. So, moving the help text to an implicitly selected Kconfig symbol. I would rather keep this as it is to keep it user friendly. This doesn't affect the code size anyways. The other option is to remove all the CPU specific Kconfig symbols and update the "title" to reflect both the CPU/erratum numbers. Kind regards Suzuki

3 years, 9 months

Re: [PATCH v2 2/2] arm64: dts: qcom: sm8250: Add Coresight support

by Suzuki K Poulose

Hi Tao Are there no sinks at all on this platform ? I had this question on the previous series. How is CoreSight useful on this platform otherwise ? On 13/09/2021 07:40, Tao Zhang wrote: > Add the basic coresight components found on Qualcomm SM8250 Soc. The > basic coresight components include ETF, ETMs,STM and the related > funnels. > > Signed-off-by: Tao Zhang <quic_taozha(a)quicinc.com> > --- > arch/arm64/boot/dts/qcom/qrb5165-rb5.dts | 442 ++++++++++++++++++++++- > 1 file changed, 438 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts b/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts > index 8ac96f8e79d4..9c8f87d80afc 100644 > --- a/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts > +++ b/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts > @@ -222,11 +222,445 @@ > regulator-max-microvolt = <1800000>; > regulator-always-on; > }; > -}; > > -&adsp { > - status = "okay"; > - firmware-name = "qcom/sm8250/adsp.mbn"; Unrelated change ? Please keep it separate from the CoreSight changes. Suzuki

3 years, 9 months

Re: [PATCH v2 0/2] Add Coresight support for RB5 board

by Suzuki K Poulose

Hi Tao On 13/09/2021 07:40, Tao Zhang wrote: > This series adds Coresight support for SM8250 Soc on RB5 board. > It is composed of two elements. > a) Add ETM PID for Kryo-5XX. > b) Add coresight support to DTS for RB5. > > This series applies to coresight/next > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git > Please could you mention what has changed since the previous version in the cover letter ? Kind regards Suzuki > Tao Zhang (2): > coresight: etm4x: Add ETM PID for Kryo-5XX > arm64: dts: qcom: sm8250: Add Coresight support > > arch/arm64/boot/dts/qcom/qrb5165-rb5.dts | 442 +++++++++++++++++- > .../coresight/coresight-etm4x-core.c | 1 + > 2 files changed, 439 insertions(+), 4 deletions(-) >

3 years, 9 months

Re: [PATCH v2 1/2] coresight: etm4x: Add ETM PID for Kryo-5XX

by Suzuki K Poulose

On 13/09/2021 07:40, Tao Zhang wrote: > Add ETM PID for Kryo-5XX to the list of supported ETMs. > Otherwise, Kryo-5XX ETMs will not be initialized successfully. > e.g. > This change can be verified on qrb5165-rb5 board. ETM4-ETM7 nodes > will not be visible without this change. > > Signed-off-by: Tao Zhang <quic_taozha(a)quicinc.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose(a)arm.com> > --- > drivers/hwtracing/coresight/coresight-etm4x-core.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c > index da27cd4a3c38..52ca918c3bec 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > @@ -2065,6 +2065,7 @@ static const struct amba_id etm4_ids[] = { > CS_AMBA_UCI_ID(0x000bb803, uci_id_etm4),/* Qualcomm Kryo 385 Cortex-A75 */ > CS_AMBA_UCI_ID(0x000bb805, uci_id_etm4),/* Qualcomm Kryo 4XX Cortex-A55 */ > CS_AMBA_UCI_ID(0x000bb804, uci_id_etm4),/* Qualcomm Kryo 4XX Cortex-A76 */ > + CS_AMBA_UCI_ID(0x000bbd0d, uci_id_etm4),/* Qualcomm Kryo 5XX Cortex-A77 */ > CS_AMBA_UCI_ID(0x000cc0af, uci_id_etm4),/* Marvell ThunderX2 */ > CS_AMBA_UCI_ID(0x000b6d01, uci_id_etm4),/* HiSilicon-Hip08 */ > CS_AMBA_UCI_ID(0x000b6d02, uci_id_etm4),/* HiSilicon-Hip09 */ >

3 years, 9 months

[PATCH] coresight: cpu-debug: control default behavior via Kconfig

by Brian Norris

Debugfs is nice and so are module parameters, but * debugfs doesn't take effect early (e.g., if drivers are locking up before user space gets anywhere) * module parameters either add a lot to the kernel command line, or else take effect late as well (if you build =m and configure in /etc/modprobe.d/) So in the same spirit as these CONFIG_PANIC_ON_OOPS (also available via cmdline or modparam) CONFIG_INTEL_IOMMU_DEFAULT_ON (also available via cmdline) add a new Kconfig option. Module parameters and debugfs can still override. Signed-off-by: Brian Norris <briannorris(a)chromium.org> --- drivers/hwtracing/coresight/Kconfig | 13 +++++++++++++ drivers/hwtracing/coresight/coresight-cpu-debug.c | 2 +- 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig index f026e5c0e777..8b638eb3cb7d 100644 --- a/drivers/hwtracing/coresight/Kconfig +++ b/drivers/hwtracing/coresight/Kconfig @@ -150,6 +150,19 @@ config CORESIGHT_CPU_DEBUG To compile this driver as a module, choose M here: the module will be called coresight-cpu-debug. +config CORESIGHT_CPU_DEBUG_DEFAULT_ON + bool "Enable CoreSight CPU Debug by default + depends on CORESIGHT_CPU_DEBUG + help + Say Y here to enable the CoreSight Debug panic-debug by default. This + can also be enabled via debugfs, but this ensures the debug feature + is enabled as early as possible. + + Has the same effect as setting coresight_cpu_debug.enable=1 on the + kernel command line. + + Say N if unsure. + config CORESIGHT_CTI tristate "CoreSight Cross Trigger Interface (CTI) driver" depends on ARM || ARM64 diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c index 00de46565bc4..8845ec4b4402 100644 --- a/drivers/hwtracing/coresight/coresight-cpu-debug.c +++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c @@ -105,7 +105,7 @@ static DEFINE_PER_CPU(struct debug_drvdata *, debug_drvdata); static int debug_count; static struct dentry *debug_debugfs_dir; -static bool debug_enable; +static bool debug_enable = IS_ENABLED(CONFIG_CORESIGHT_CPU_DEBUG_DEFAULT_ON); module_param_named(enable, debug_enable, bool, 0600); MODULE_PARM_DESC(enable, "Control to enable coresight CPU debug functionality"); -- 2.33.0.153.gba50c8fa24-goog

3 years, 9 months

[PATCH v4] coresight: tmc-etr: Speed up for bounce buffer in flat mode

by Leo Yan

The AUX bounce buffer is allocated with API dma_alloc_coherent(), in the low level's architecture code, e.g. for Arm64, it maps the memory with the attribution "Normal non-cacheable"; this can be concluded from the definition for pgprot_dmacoherent() in arch/arm64/include/asm/pgtable.h. Later when access the AUX bounce buffer, since the memory mapping is non-cacheable, it's low efficiency due to every load instruction must reach out DRAM. This patch changes to allocate pages with dma_alloc_noncoherent(), the driver can access the memory via cacheable mapping; therefore, load instructions can fetch data from cache lines rather than always read data from DRAM, the driver can boost memory performance. After using the cacheable mapping, the driver uses dma_sync_single_for_cpu() to invalidate cacheline prior to read bounce buffer so can avoid read stale trace data. By measurement the duration for function tmc_update_etr_buffer() with ftrace function_graph tracer, it shows the performance significant improvement for copying 4MiB data from bounce buffer: # echo tmc_etr_get_data_flat_buf > set_graph_notrace // avoid noise # echo tmc_update_etr_buffer > set_graph_function # echo function_graph > current_tracer before: # CPU DURATION FUNCTION CALLS # | | | | | | | 2) | tmc_update_etr_buffer() { ... 2) # 8148.320 us | } after: # CPU DURATION FUNCTION CALLS # | | | | | | | 2) | tmc_update_etr_buffer() { ... 2) # 2525.420 us | } Signed-off-by: Leo Yan <leo.yan(a)linaro.org> Reviewed-by: Suzuki K Poulose <suzuki.poulose(a)arm.com> --- Changes from v3: Refined change to use dma_alloc_noncoherent()/dma_free_noncoherent() (Robin Murphy); Retested functionality and performance on Juno-r2 board. Changes from v2: Sync the entire buffer in one go when the tracing is wrap around (Suzuki); Add Suzuki's review tage. .../hwtracing/coresight/coresight-tmc-etr.c | 26 ++++++++++++++++--- 1 file changed, 22 insertions(+), 4 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index acdb59e0e661..a049b525a274 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -609,8 +609,9 @@ static int tmc_etr_alloc_flat_buf(struct tmc_drvdata *drvdata, if (!flat_buf) return -ENOMEM; - flat_buf->vaddr = dma_alloc_coherent(real_dev, etr_buf->size, - &flat_buf->daddr, GFP_KERNEL); + flat_buf->vaddr = dma_alloc_noncoherent(real_dev, etr_buf->size, + &flat_buf->daddr, + DMA_FROM_DEVICE, GFP_KERNEL); if (!flat_buf->vaddr) { kfree(flat_buf); return -ENOMEM; @@ -631,14 +632,18 @@ static void tmc_etr_free_flat_buf(struct etr_buf *etr_buf) if (flat_buf && flat_buf->daddr) { struct device *real_dev = flat_buf->dev->parent; - dma_free_coherent(real_dev, flat_buf->size, - flat_buf->vaddr, flat_buf->daddr); + dma_free_noncoherent(real_dev, etr_buf->size, + flat_buf->vaddr, flat_buf->daddr, + DMA_FROM_DEVICE); } kfree(flat_buf); } static void tmc_etr_sync_flat_buf(struct etr_buf *etr_buf, u64 rrp, u64 rwp) { + struct etr_flat_buf *flat_buf = etr_buf->private; + struct device *real_dev = flat_buf->dev->parent; + /* * Adjust the buffer to point to the beginning of the trace data * and update the available trace data. @@ -648,6 +653,19 @@ static void tmc_etr_sync_flat_buf(struct etr_buf *etr_buf, u64 rrp, u64 rwp) etr_buf->len = etr_buf->size; else etr_buf->len = rwp - rrp; + + /* + * The driver always starts tracing at the beginning of the buffer, + * the only reason why we would get a wrap around is when the buffer + * is full. Sync the entire buffer in one go for this case. + */ + if (etr_buf->offset + etr_buf->len > etr_buf->size) + dma_sync_single_for_cpu(real_dev, flat_buf->daddr, + etr_buf->size, DMA_FROM_DEVICE); + else + dma_sync_single_for_cpu(real_dev, + flat_buf->daddr + etr_buf->offset, + etr_buf->len, DMA_FROM_DEVICE); } static ssize_t tmc_etr_get_data_flat_buf(struct etr_buf *etr_buf, -- 2.25.1

3 years, 9 months

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