This series makes ETM TRCCCCTRL based 'cc_threshold' user configurable via
the perf event attribute. But first, this implements an errata work around
affecting ETM TRCIDR3.CCITMIN value on certain cpus, overriding the field.
This series applies on v6.5-rc5.
Cc: Catalin Marinas <catalin.marinas(a)arm.com>
Cc: Will Deacon <will(a)kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose(a)arm.com>
Cc: Mike Leach <mike.leach(a)linaro.org>
Cc: James Clark <james.clark(a)arm.com>
Cc: Leo Yan <leo.yan(a)linaro.org>
Cc: Jonathan Corbet <corbet(a)lwn.net>
Cc: linux-doc(a)vger.kernel.org
Cc: coresight(a)lists.linaro.org
Cc: linux-arm-kernel(a)lists.infradead.org
Cc: linux-kernel(a)vger.kernel.org
Changes in V3:
- Added errata work around affecting TRCIDR3.CCITMIN
- Split the document update into a separate patch
Changes in V2:
https://lore.kernel.org/all/20230808074533.380537-1-anshuman.khandual@arm.c…
- s/treshhold/threshold
Changes in V1:
https://lore.kernel.org/all/20230804044720.1478900-1-anshuman.khandual@arm.…
Anshuman Khandual (3):
coresight: etm: Override TRCIDR3.CCITMIN on errata affected cpus
coresight: etm: Make cycle count threshold user configurable
Documentation: coresight: Add cc_threshold tunable
Documentation/arch/arm64/silicon-errata.rst | 10 ++++
Documentation/trace/coresight/coresight.rst | 4 ++
.../hwtracing/coresight/coresight-etm-perf.c | 2 +
.../coresight/coresight-etm4x-core.c | 49 ++++++++++++++++++-
4 files changed, 63 insertions(+), 2 deletions(-)
--
2.25.1
Hi Yabin
On 17/08/2023 22:06, Yabin Cui wrote:
> Hi coresight driver maintainers,
>
> I am from the Android toolchain team. I am trying to use ETE (Embedded
> Trace Extension). But on my device, the system crashes when the ETM
> driver is trying to read TRCDEVARCH via sysreg interface.
When you say crashes, what exactly is reported ? Does the kernel
get an exception ? Or system hangs completely ?
I suspect :
1) You are running some hyp at EL2, which doesn't allow
accessing the TRC* registers and injects a Illegal instruction ?
2) If not the above, the ETE is not powered (very unlikely)
Suzuki
> In
> https://github.com/torvalds/linux/blob/master/drivers/hwtracing/coresight/c… <https://github.com/torvalds/linux/blob/master/drivers/hwtracing/coresight/c…> :
>
> static bool etm4_init_sysreg_access(struct etmv4_drvdata *drvdata,
> struct csdev_access *csa)
> {
> u32 devarch;
>
> if (!cpu_supports_sysreg_trace()) <- this returns true
> return false;
>
> /*
> * ETMs implementing sysreg access must implement TRCDEVARCH.
> */
> devarch = read_etm4x_sysreg_const_offset(TRCDEVARCH); <- never see the
> message logged immediately after this line, so should abort here.
> ...
> }
>
> Do you have any suggestions on how I can debug the problem? Is there any
> other place making sysreg interface to ETE not accessible? Or can the
> ETE sysreg interface not be implemented?
> I tried the memory mapped register interface of ETE, it works fine. The
> only change I need is to bypass the devarch version check
> in etm4_init_iomem_access, in in
> https://github.com/torvalds/linux/blob/master/drivers/hwtracing/coresight/c… <https://github.com/torvalds/linux/blob/master/drivers/hwtracing/coresight/c…>
> I wonder if we can allow iomem access for ETE if the sysreg access
> doesn't work on some devices.
>
> Thanks,
> Yabin
This validates 'drvdata' and 'drvdata->pclk' clock before calling clk_put()
in etm4_remove_platform_dev(). The problem was detected using Smatch static
checker as reported.
Cc: Suzuki K Poulose <suzuki.poulose(a)arm.com>
Cc: Mike Leach <mike.leach(a)linaro.org>
Cc: James Clark <james.clark(a)arm.com>
Cc: coresight(a)lists.linaro.org
Cc: linux-arm-kernel(a)lists.infradead.org
Cc: linux-kernel(a)vger.kernel.org
Reported-by: Dan Carpenter <dan.carpenter(a)linaro.org>
Closes: https://lists.linaro.org/archives/list/coresight@lists.linaro.org/thread/G4…
Reviewed-by: James Clark <james.clark(a)arm.com>
Reviewed-by: Mike Leach <mike.leach(a)lnaro.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual(a)arm.com>
---
This applies on coresight-next
Changes in V2:
- Dropped drvdata->pclk check for non-NULL
- Replaced IS_ERR() with IS_ERR_OR_NULL() for drvdata->pclk
Changes in V1:
https://lore.kernel.org/all/20230811062738.1066787-1-anshuman.khandual@arm.…
drivers/hwtracing/coresight/coresight-etm4x-core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 703b6fcbb6a5..77b0271ce6eb 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -2269,7 +2269,7 @@ static int __exit etm4_remove_platform_dev(struct platform_device *pdev)
etm4_remove_dev(drvdata);
pm_runtime_disable(&pdev->dev);
- if (drvdata->pclk)
+ if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
clk_put(drvdata->pclk);
return 0;
--
2.25.1
The TRBE driver support is build as a module, we found some driver issues
based on the patchset [1] and set CONFIG_CORESIGHT_TRBE=m.
1. TRBE driver potential sleep in atomic context when unregister device
2. Multiple free the platform data resource when rmmod coresight TRBE
driver
[1] "coresight: trbe: Enable ACPI based devices"
https://lore.kernel.org/all/20230808082247.383405-1-anshuman.khandual@arm.c…
Junhao He (2):
coresight: trbe: Fix TRBE potential sleep in atomic context
coresight: core: Fix multiple free TRBE platform data resource
drivers/hwtracing/coresight/coresight-core.c | 7 ++--
drivers/hwtracing/coresight/coresight-trbe.c | 35 +++++++++++---------
2 files changed, 24 insertions(+), 18 deletions(-)
--
2.33.0
This series enables detection of ACPI based TRBE devices via a stand alone
purpose built representative platform device. But as a pre-requisite this
changes coresight_platform_data structure assignment for the TRBE device.
This series is based on v6.5-rc5 kernel, is also dependent on the following
EDK2 changes posted earlier by Sami.
https://edk2.groups.io/g/devel/message/107239https://edk2.groups.io/g/devel/message/107241
Changes in V5:
- Detected zeroed parsed GSI as a mismatch but handled all zero scenario
- Changed condition check from 'if (ret < 0)' into a 'if (ret)'
- Dropped pr_warn() message after platform_device_register()
Changes in V4:
https://lore.kernel.org/all/20230808082247.383405-1-anshuman.khandual@arm.c…
- Added in-code comment for arm_trbe_device_probe()
- Reverted back using IS_ENABLED() for SPE PMU platform device
- Replaced #ifdef with IS_ENABLED() for TRBE platform device
- Protected arm_trbe_acpi_match with ACPI_PTR() - preventing a build failure
when CONFIG_ACPI is not enabled
- Added __maybe_unused for arm_acpi_register_pmu_device() and dropped config
checks with IS_ENABLED()
Changes in V3:
https://lore.kernel.org/all/20230803055652.1322801-1-anshuman.khandual@arm.…
- Changed ARMV8_TRBE_PDEV_NAME from "arm-trbe-acpi" into "arm,trbe"
- Dropped local variable 'matched'
- Replaced 'matched' with 'valid gsi' as being already matched once
- Moved find_acpi_cpu_topology_hetero_id() outside conditional check
Changes in V2:
https://lore.kernel.org/all/20230801094052.750416-1-anshuman.khandual@arm.c…
- Refactored arm_spe_acpi_register_device() in a separate patch
- Renamed trbe_acpi_resources as trbe_resources
- Renamed trbe_acpi_dev as trbe_dev
Changes in V1:
https://lore.kernel.org/all/20230728112733.359620-1-anshuman.khandual@arm.c…
Cc: Sami Mujawar <sami.mujawar(a)arm.com>
Cc: Catalin Marinas <catalin.marinas(a)arm.com>
Cc: Will Deacon <will(a)kernel.org>
Cc: Mark Rutland <mark.rutland(a)arm.com>
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>
Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com>
Cc: James Clark <james.clark(a)arm.com>
Cc: coresight(a)lists.linaro.org
Cc: linux-arm-kernel(a)lists.infradead.org
Cc: linux-kernel(a)vger.kernel.org
Anshuman Khandual (4):
arm_pmu: acpi: Refactor arm_spe_acpi_register_device()
arm_pmu: acpi: Add a representative platform device for TRBE
coresight: trbe: Add a representative coresight_platform_data for TRBE
coresight: trbe: Enable ACPI based TRBE devices
arch/arm64/include/asm/acpi.h | 3 +
drivers/hwtracing/coresight/coresight-trbe.c | 26 +++-
drivers/hwtracing/coresight/coresight-trbe.h | 2 +
drivers/perf/arm_pmu_acpi.c | 142 ++++++++++++++-----
include/linux/perf/arm_pmu.h | 1 +
5 files changed, 132 insertions(+), 42 deletions(-)
--
2.25.1
On 15/08/2023 10:40, John Garry wrote:
> On 11/08/2023 15:39, James Clark wrote:
>> N2 r0p3 doesn't require the workaround [1], so gating on (#slots - 5) no
>> longer works because all N2s have 5 slots. Add a new expression builtin
>> that allows calling strcmp_cpuid_str() and comparing CPUIDs in metric
>> formulas.
>>
>> In this case, the commented formula looks like this:
>>
>> strcmp_cpuid_str(0x410fd493) # greater than or equal to N2 r0p3
>> | strcmp_cpuid_str(0x410fd490) ^ 1 # OR NOT any version of N2
>>
>> [1]:https://urldefense.com/v3/__https://gitlab.arm.com/telemetry-solution/te… Signed-off-by: James Clark<james.clark(a)arm.com>
>> ---
>> tools/perf/arch/arm64/util/pmu.c | 18 +-----------------
>> .../arch/arm64/arm/neoverse-n2-v2/metrics.json | 8 ++++----
>> tools/perf/pmu-events/metric.py | 17 +++++++++++++++--
>> tools/perf/util/expr.c | 18 ++++++++++++++++++
>> tools/perf/util/expr.h | 1 +
>> tools/perf/util/expr.l | 1 +
>> tools/perf/util/expr.y | 8 +++++++-
>> tools/perf/util/pmu.c | 17 +++++++++++++++++
>> tools/perf/util/pmu.h | 1 +
>> 9 files changed, 65 insertions(+), 24 deletions(-)
>
> This patch looks ok, but I think that it would be better to separate out
> the metrics.json change into a separate patch.
>
Yep I thought about doing that, I can change it in the next version.
> Thanks,
> John
On 15/08/2023 10:35, John Garry wrote:
> On 11/08/2023 15:39, James Clark wrote:
>> Currently variant and revision fields are masked out of the MIDR so
>> it's not possible to compare different versions of the same CPU.
>> In a later commit a workaround will be removed just for N2 r0p3, so
>> enable comparisons on version.
>>
>> This has the side effect of changing the MIDR stored in the header of
>> the perf.data file to no longer have masked version fields. It also
>> affects the lookups in mapfile.csv, but as that currently only has
>> zeroed version fields, it has no actual effect. The mapfile.csv
>> documentation also states to zero the version fields, so unless this
>> isn't done it will continue to have no effect.
>>
>
> This looks ok apart from a couple of comments, below.
>
> Thanks,
> John
>
>> Signed-off-by: James Clark <james.clark(a)arm.com>
>> ---
>> tools/perf/arch/arm64/util/header.c | 64 ++++++++++++++++++++++-------
>> 1 file changed, 50 insertions(+), 14 deletions(-)
>>
>> diff --git a/tools/perf/arch/arm64/util/header.c
>> b/tools/perf/arch/arm64/util/header.c
>> index 80b9f6287fe2..8f74e801e1ab 100644
>> --- a/tools/perf/arch/arm64/util/header.c
>> +++ b/tools/perf/arch/arm64/util/header.c
>> @@ -1,3 +1,6 @@
>> +#include <linux/kernel.h>
>> +#include <linux/bits.h>
>> +#include <linux/bitfield.h>
>> #include <stdio.h>
>> #include <stdlib.h>
>> #include <perf/cpumap.h>
>> @@ -10,14 +13,12 @@
>> #define MIDR "/regs/identification/midr_el1"
>> #define MIDR_SIZE 19
>> -#define MIDR_REVISION_MASK 0xf
>> -#define MIDR_VARIANT_SHIFT 20
>> -#define MIDR_VARIANT_MASK (0xf << MIDR_VARIANT_SHIFT)
>> +#define MIDR_REVISION_MASK GENMASK(3, 0)
>> +#define MIDR_VARIANT_MASK GENMASK(23, 20)
>> static int _get_cpuid(char *buf, size_t sz, struct perf_cpu_map
>> *cpus)
>> {
>> const char *sysfs = sysfs__mountpoint();
>> - u64 midr = 0;
>> int cpu;
>> if (!sysfs || sz < MIDR_SIZE)
>> @@ -44,21 +45,11 @@ static int _get_cpuid(char *buf, size_t sz, struct
>> perf_cpu_map *cpus)
>> }
>> fclose(file);
>> - /* Ignore/clear Variant[23:20] and
>> - * Revision[3:0] of MIDR
>> - */
>> - midr = strtoul(buf, NULL, 16);
>> - midr &= (~(MIDR_VARIANT_MASK | MIDR_REVISION_MASK));
>> - scnprintf(buf, MIDR_SIZE, "0x%016lx", midr);
>> /* got midr break loop */
>> break;
>> }
>> perf_cpu_map__put(cpus);
>> -
>> - if (!midr)
>> - return EINVAL;
>
> Is there a reason to drop this check?
>
> As I see, it is still checked in perf_pmu__getcpudid() ->
> get_cpuid_str() -> _get_cpuid(), and we don't zero the buf allocated in
> _get_cpuid()
>
Ah yes, now if all the files fail to open or read then buf will be
uninitialized. I make it so that it will return EINVAL unless the
fgets() succeeds, but I don't think we need to add the strtoul() back in?
>> -
>> return 0;
>> }
>> @@ -99,3 +90,48 @@ char *get_cpuid_str(struct perf_pmu *pmu)
>> return buf;
>> }
>> +
>> +/*
>> + * Return 0 if idstr is a higher or equal to version of the same part as
>> + * mapcpuid.
>
> And what other values may be returned? If just 0/1, then can we have a
> bool return value?
>
I don't think that's best for consistency. All the other CPU ID
comparison functions return the strcmp style return values which is the
reverse of booleans. We could change them all to bool, but it would be a
big change, and they'd still have strcmp in the name which suggests
-1/0/1 return values (although -1 is never used here).
I will add to the comment that 1 is returned for a comparison failure
thought. That is missing.
>> + *
>> + * Therefore, if mapcpuid has 0 for revision and variant then any
>> version of
>> + * idstr will match as long as it's the same CPU type.
>> + */
>> +int strcmp_cpuid_str(const char *mapcpuid, const char *idstr)
>> +{
>> + u64 map_id = strtoull(mapcpuid, NULL, 16);
>> + char map_id_variant = FIELD_GET(MIDR_VARIANT_MASK, map_id);
>> + char map_id_revision = FIELD_GET(MIDR_REVISION_MASK, map_id);
>> + u64 id = strtoull(idstr, NULL, 16);
>> + char id_variant = FIELD_GET(MIDR_VARIANT_MASK, id);
>> + char id_revision = FIELD_GET(MIDR_REVISION_MASK, id);
>> + u64 id_fields = ~(MIDR_VARIANT_MASK | MIDR_REVISION_MASK);
>> +
>> + /* Compare without version first */
>> + if ((map_id & id_fields) != (id & id_fields))
>> + return 1;
>> +
>> + /*
>> + * ID matches, now compare version.
>> + *
>> + * Arm revisions (like r0p0) are compared here like two digit semver
>> + * values eg. 1.3 < 2.0 < 2.1 < 2.2. The events json file with the
>> + * highest matching version is used.
>> + *
>> + * r = high value = 'Variant' field in MIDR
>> + * p = low value = 'Revision' field in MIDR
>> + *
>> + */
>> + if (id_variant > map_id_variant)
>> + return 0;
>> +
>> + if (id_variant == map_id_variant && id_revision >= map_id_revision)
>> + return 0;
>> +
>> + /*
>> + * variant is less than mapfile variant or variants are the same but
>> + * the revision doesn't match. Return no match.
>> + */
>> + return 1;
>> +}
>