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@arm.com Cc: Will Deacon will@kernel.org Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Leo Yan leo.yan@linaro.org Cc: Jonathan Corbet corbet@lwn.net Cc: linux-doc@vger.kernel.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@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.co...
- s/treshhold/threshold
Changes in V1:
https://lore.kernel.org/all/20230804044720.1478900-1-anshuman.khandual@arm.c...
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(-)
This work arounds errata 1490853 on Cortex-A76, and Neoverse-N1, errata 1491015 on Cortex-A77, errata 1502854 on Cortex-X1, and errata 1619801 on Neoverse-V1, based affected cpus, where software read for TRCIDR3.CCITMIN field in ETM gets an wrong value.
If software uses the value returned by the TRCIDR3.CCITMIN register field, then it will limit the range which could be used for programming the ETM. In reality, the ETM could be programmed with a much smaller value than what is indicated by the TRCIDR3.CCITMIN field and still function correctly.
If software reads the TRCIDR3.CCITMIN register field, corresponding to the instruction trace counting minimum threshold, observe the value 0x100 or a minimum cycle count threshold of 256. The correct value should be 0x4 or a minimum cycle count threshold of 4.
This work arounds the problem via storing 4 in drvdata->ccitmin on affected systems where the TRCIDR3.CCITMIN has been 256, thus preserving cycle count threshold granularity.
These errata information has been updated in arch/arm64/silicon-errata.rst, but without their corresponding configs because these have been implemented directly in the driver.
Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will@kernel.org Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Jonathan Corbet corbet@lwn.net Cc: linux-doc@vger.kernel.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com --- Documentation/arch/arm64/silicon-errata.rst | 10 +++++ .../coresight/coresight-etm4x-core.c | 37 +++++++++++++++++++ 2 files changed, 47 insertions(+)
diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst index bedd3a1d7b42..b08f33eda5f1 100644 --- a/Documentation/arch/arm64/silicon-errata.rst +++ b/Documentation/arch/arm64/silicon-errata.rst @@ -107,6 +107,10 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A76 | #1463225 | ARM64_ERRATUM_1463225 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A76 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A77 | #1491015 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A77 | #1508412 | ARM64_ERRATUM_1508412 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A510 | #2051678 | ARM64_ERRATUM_2051678 | @@ -125,6 +129,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A715 | #2645198 | ARM64_ERRATUM_2645198 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-X1 | #1502854 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2119858 | ARM64_ERRATUM_2119858 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2224489 | ARM64_ERRATUM_2224489 | @@ -133,6 +139,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1349291 | N/A | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-N1 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2139208 | ARM64_ERRATUM_2139208 | @@ -141,6 +149,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2253138 | ARM64_ERRATUM_2253138 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-V1 | #1619801 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-500 | #841119,826419 | N/A | +----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-600 | #1076982,1209401| N/A | diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 703b6fcbb6a5..1f3d29a639ff 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1150,6 +1150,31 @@ static void cpu_detect_trace_filtering(struct etmv4_drvdata *drvdata) drvdata->trfcr = trfcr; }
+/* + * The following errata on applicable cpu rangess affect the CCITMIN filed + * in TCRIDR3 register. Software read for the field returns 0x100 limiting + * the cycle threshold granularity, where as the right value should have + * been 0x4, which is well supported in the hardware. + */ +static struct midr_range etm_wrong_ccitmin_cpus[] = { + /* Erratum #1490853 - Cortex-A76 */ + MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 4, 0), + /* Erratum #1490853 - Neoverse-N1 */ + MIDR_RANGE(MIDR_NEOVERSE_N1, 0, 0, 4, 0), + /* Erratum #1491015 - Cortex-A77 */ + MIDR_RANGE(MIDR_CORTEX_A77, 0, 0, 1, 0), + /* Erratum #1502854 - Cortex-X1 */ + MIDR_REV(MIDR_CORTEX_X1, 0, 0), + /* Erratum #1619801 - Neoverse-V1 */ + MIDR_REV(MIDR_NEOVERSE_V1, 0, 0), + {}, +}; + +static bool etm4_work_around_wrong_ccitmin(void) +{ + return is_midr_in_range_list(read_cpuid_id(), etm_wrong_ccitmin_cpus); +} + static void etm4_init_arch_data(void *info) { u32 etmidr0; @@ -1214,6 +1239,18 @@ static void etm4_init_arch_data(void *info) etmidr3 = etm4x_relaxed_read32(csa, TRCIDR3); /* CCITMIN, bits[11:0] minimum threshold value that can be programmed */ drvdata->ccitmin = FIELD_GET(TRCIDR3_CCITMIN_MASK, etmidr3); + if (etm4_work_around_wrong_ccitmin()) { + /* + * Erratum affected cpus will read 256 as the minimum + * instruction trace cycle counting threshold where as + * the correct value should be 4 instead. Override the + * recorded value for 'drvdata->ccitmin' to workaround + * this problem. + */ + if (drvdata->ccitmin == 256) + drvdata->ccitmin = 4; + } + /* EXLEVEL_S, bits[19:16] Secure state instruction tracing */ drvdata->s_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_S_MASK, etmidr3); drvdata->config.s_ex_level = drvdata->s_ex_level;
Hi Anshuman,
A few minor points.
On Fri, 11 Aug 2023 at 04:46, Anshuman Khandual anshuman.khandual@arm.com wrote:
This work arounds errata 1490853 on Cortex-A76, and Neoverse-N1, errata 1491015 on Cortex-A77, errata 1502854 on Cortex-X1, and errata 1619801 on Neoverse-V1, based affected cpus, where software read for TRCIDR3.CCITMIN field in ETM gets an wrong value.
If software uses the value returned by the TRCIDR3.CCITMIN register field, then it will limit the range which could be used for programming the ETM. In reality, the ETM could be programmed with a much smaller value than what is indicated by the TRCIDR3.CCITMIN field and still function correctly.
If software reads the TRCIDR3.CCITMIN register field, corresponding to the instruction trace counting minimum threshold, observe the value 0x100 or a minimum cycle count threshold of 256. The correct value should be 0x4 or a minimum cycle count threshold of 4.
This work arounds the problem via storing 4 in drvdata->ccitmin on affected systems where the TRCIDR3.CCITMIN has been 256, thus preserving cycle count threshold granularity.
These errata information has been updated in arch/arm64/silicon-errata.rst, but without their corresponding configs because these have been implemented directly in the driver.
Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will@kernel.org Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Jonathan Corbet corbet@lwn.net Cc: linux-doc@vger.kernel.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com
Documentation/arch/arm64/silicon-errata.rst | 10 +++++ .../coresight/coresight-etm4x-core.c | 37 +++++++++++++++++++ 2 files changed, 47 insertions(+)
diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst index bedd3a1d7b42..b08f33eda5f1 100644 --- a/Documentation/arch/arm64/silicon-errata.rst +++ b/Documentation/arch/arm64/silicon-errata.rst @@ -107,6 +107,10 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A76 | #1463225 | ARM64_ERRATUM_1463225 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A76 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A77 | #1491015 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A77 | #1508412 | ARM64_ERRATUM_1508412 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A510 | #2051678 | ARM64_ERRATUM_2051678 | @@ -125,6 +129,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A715 | #2645198 | ARM64_ERRATUM_2645198 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-X1 | #1502854 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2119858 | ARM64_ERRATUM_2119858 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2224489 | ARM64_ERRATUM_2224489 | @@ -133,6 +139,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1349291 | N/A | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-N1 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2139208 | ARM64_ERRATUM_2139208 | @@ -141,6 +149,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2253138 | ARM64_ERRATUM_2253138 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-V1 | #1619801 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-500 | #841119,826419 | N/A | +----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-600 | #1076982,1209401| N/A |
Could these doc changes not go in patch 3?
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 703b6fcbb6a5..1f3d29a639ff 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1150,6 +1150,31 @@ static void cpu_detect_trace_filtering(struct etmv4_drvdata *drvdata) drvdata->trfcr = trfcr; }
+/*
- The following errata on applicable cpu rangess affect the CCITMIN filed
s/rangess/ranges
- in TCRIDR3 register. Software read for the field returns 0x100 limiting
- the cycle threshold granularity, where as the right value should have
- been 0x4, which is well supported in the hardware.
- */
+static struct midr_range etm_wrong_ccitmin_cpus[] = {
/* Erratum #1490853 - Cortex-A76 */MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 4, 0),/* Erratum #1490853 - Neoverse-N1 */MIDR_RANGE(MIDR_NEOVERSE_N1, 0, 0, 4, 0),/* Erratum #1491015 - Cortex-A77 */MIDR_RANGE(MIDR_CORTEX_A77, 0, 0, 1, 0),/* Erratum #1502854 - Cortex-X1 */MIDR_REV(MIDR_CORTEX_X1, 0, 0),/* Erratum #1619801 - Neoverse-V1 */MIDR_REV(MIDR_NEOVERSE_V1, 0, 0),{},+};
+static bool etm4_work_around_wrong_ccitmin(void)
This is not the actual work around - perhaps this should be etm4_core_reads_wrong_ccitmin()?
+{
return is_midr_in_range_list(read_cpuid_id(), etm_wrong_ccitmin_cpus);+}
static void etm4_init_arch_data(void *info) { u32 etmidr0; @@ -1214,6 +1239,18 @@ static void etm4_init_arch_data(void *info) etmidr3 = etm4x_relaxed_read32(csa, TRCIDR3); /* CCITMIN, bits[11:0] minimum threshold value that can be programmed */ drvdata->ccitmin = FIELD_GET(TRCIDR3_CCITMIN_MASK, etmidr3);
if (etm4_work_around_wrong_ccitmin()) {/** Erratum affected cpus will read 256 as the minimum* instruction trace cycle counting threshold where as* the correct value should be 4 instead. Override the* recorded value for 'drvdata->ccitmin' to workaround* this problem.*/if (drvdata->ccitmin == 256)
Not sure this check matters - fixed cores will be 4, non fixed cores as identified by the list need to be 4, we don't care what the read value is if the core is on the list.
drvdata->ccitmin = 4;}/* EXLEVEL_S, bits[19:16] Secure state instruction tracing */ drvdata->s_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_S_MASK, etmidr3); drvdata->config.s_ex_level = drvdata->s_ex_level;-- 2.25.1
Regards
Mike
On 11/08/2023 10:03, Mike Leach wrote:
Hi Anshuman,
A few minor points.
On Fri, 11 Aug 2023 at 04:46, Anshuman Khandual anshuman.khandual@arm.com wrote:
This work arounds errata 1490853 on Cortex-A76, and Neoverse-N1, errata 1491015 on Cortex-A77, errata 1502854 on Cortex-X1, and errata 1619801 on Neoverse-V1, based affected cpus, where software read for TRCIDR3.CCITMIN field in ETM gets an wrong value.
If software uses the value returned by the TRCIDR3.CCITMIN register field, then it will limit the range which could be used for programming the ETM. In reality, the ETM could be programmed with a much smaller value than what is indicated by the TRCIDR3.CCITMIN field and still function correctly.
If software reads the TRCIDR3.CCITMIN register field, corresponding to the instruction trace counting minimum threshold, observe the value 0x100 or a minimum cycle count threshold of 256. The correct value should be 0x4 or a minimum cycle count threshold of 4.
This work arounds the problem via storing 4 in drvdata->ccitmin on affected systems where the TRCIDR3.CCITMIN has been 256, thus preserving cycle count threshold granularity.
These errata information has been updated in arch/arm64/silicon-errata.rst, but without their corresponding configs because these have been implemented directly in the driver.
Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will@kernel.org Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Jonathan Corbet corbet@lwn.net Cc: linux-doc@vger.kernel.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com
Documentation/arch/arm64/silicon-errata.rst | 10 +++++ .../coresight/coresight-etm4x-core.c | 37 +++++++++++++++++++ 2 files changed, 47 insertions(+)
diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst index bedd3a1d7b42..b08f33eda5f1 100644 --- a/Documentation/arch/arm64/silicon-errata.rst +++ b/Documentation/arch/arm64/silicon-errata.rst @@ -107,6 +107,10 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A76 | #1463225 | ARM64_ERRATUM_1463225 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A76 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A77 | #1491015 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A77 | #1508412 | ARM64_ERRATUM_1508412 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A510 | #2051678 | ARM64_ERRATUM_2051678 | @@ -125,6 +129,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A715 | #2645198 | ARM64_ERRATUM_2645198 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-X1 | #1502854 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2119858 | ARM64_ERRATUM_2119858 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2224489 | ARM64_ERRATUM_2224489 | @@ -133,6 +139,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1349291 | N/A | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-N1 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2139208 | ARM64_ERRATUM_2139208 | @@ -141,6 +149,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2253138 | ARM64_ERRATUM_2253138 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-V1 | #1619801 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-500 | #841119,826419 | N/A | +----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-600 | #1076982,1209401| N/A |
Could these doc changes not go in patch 3?
I believe no, because this patch works around the erratum and it will help anybody looking for the workaround using the list above + the patch 3 is not related to the erratum. It is simply documenting the new perf option.
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 703b6fcbb6a5..1f3d29a639ff 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1150,6 +1150,31 @@ static void cpu_detect_trace_filtering(struct etmv4_drvdata *drvdata) drvdata->trfcr = trfcr; }
+/*
- The following errata on applicable cpu rangess affect the CCITMIN filed
s/rangess/ranges
- in TCRIDR3 register. Software read for the field returns 0x100 limiting
- the cycle threshold granularity, where as the right value should have
- been 0x4, which is well supported in the hardware.
- */
+static struct midr_range etm_wrong_ccitmin_cpus[] = {
/* Erratum #1490853 - Cortex-A76 */MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 4, 0),/* Erratum #1490853 - Neoverse-N1 */MIDR_RANGE(MIDR_NEOVERSE_N1, 0, 0, 4, 0),/* Erratum #1491015 - Cortex-A77 */MIDR_RANGE(MIDR_CORTEX_A77, 0, 0, 1, 0),/* Erratum #1502854 - Cortex-X1 */MIDR_REV(MIDR_CORTEX_X1, 0, 0),/* Erratum #1619801 - Neoverse-V1 */MIDR_REV(MIDR_NEOVERSE_V1, 0, 0),{},+};
+static bool etm4_work_around_wrong_ccitmin(void)
This is not the actual work around - perhaps this should be etm4_core_reads_wrong_ccitmin()?
+{
return is_midr_in_range_list(read_cpuid_id(), etm_wrong_ccitmin_cpus);+}
- static void etm4_init_arch_data(void *info) { u32 etmidr0;
@@ -1214,6 +1239,18 @@ static void etm4_init_arch_data(void *info) etmidr3 = etm4x_relaxed_read32(csa, TRCIDR3); /* CCITMIN, bits[11:0] minimum threshold value that can be programmed */ drvdata->ccitmin = FIELD_GET(TRCIDR3_CCITMIN_MASK, etmidr3);
if (etm4_work_around_wrong_ccitmin()) {/** Erratum affected cpus will read 256 as the minimum* instruction trace cycle counting threshold where as* the correct value should be 4 instead. Override the* recorded value for 'drvdata->ccitmin' to workaround* this problem.*/if (drvdata->ccitmin == 256) >Not sure this check matters - fixed cores will be 4, non fixed cores as identified by the list need to be 4, we don't care what the read value is if the core is on the list.
To be on the safer side, we may allow a core to have ccitmin more than 0x4 if we only fixup what is documented per erratum. So this looks fine to me.
Suzuki
drvdata->ccitmin = 4;}/* EXLEVEL_S, bits[19:16] Secure state instruction tracing */ drvdata->s_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_S_MASK, etmidr3); drvdata->config.s_ex_level = drvdata->s_ex_level;-- 2.25.1
Regards
Mike
On 8/11/23 14:33, Mike Leach wrote:
Hi Anshuman,
A few minor points.
On Fri, 11 Aug 2023 at 04:46, Anshuman Khandual anshuman.khandual@arm.com wrote:
This work arounds errata 1490853 on Cortex-A76, and Neoverse-N1, errata 1491015 on Cortex-A77, errata 1502854 on Cortex-X1, and errata 1619801 on Neoverse-V1, based affected cpus, where software read for TRCIDR3.CCITMIN field in ETM gets an wrong value.
If software uses the value returned by the TRCIDR3.CCITMIN register field, then it will limit the range which could be used for programming the ETM. In reality, the ETM could be programmed with a much smaller value than what is indicated by the TRCIDR3.CCITMIN field and still function correctly.
If software reads the TRCIDR3.CCITMIN register field, corresponding to the instruction trace counting minimum threshold, observe the value 0x100 or a minimum cycle count threshold of 256. The correct value should be 0x4 or a minimum cycle count threshold of 4.
This work arounds the problem via storing 4 in drvdata->ccitmin on affected systems where the TRCIDR3.CCITMIN has been 256, thus preserving cycle count threshold granularity.
These errata information has been updated in arch/arm64/silicon-errata.rst, but without their corresponding configs because these have been implemented directly in the driver.
Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will@kernel.org Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Jonathan Corbet corbet@lwn.net Cc: linux-doc@vger.kernel.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com
Documentation/arch/arm64/silicon-errata.rst | 10 +++++ .../coresight/coresight-etm4x-core.c | 37 +++++++++++++++++++ 2 files changed, 47 insertions(+)
diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst index bedd3a1d7b42..b08f33eda5f1 100644 --- a/Documentation/arch/arm64/silicon-errata.rst +++ b/Documentation/arch/arm64/silicon-errata.rst @@ -107,6 +107,10 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A76 | #1463225 | ARM64_ERRATUM_1463225 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A76 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A77 | #1491015 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A77 | #1508412 | ARM64_ERRATUM_1508412 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A510 | #2051678 | ARM64_ERRATUM_2051678 | @@ -125,6 +129,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A715 | #2645198 | ARM64_ERRATUM_2645198 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-X1 | #1502854 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2119858 | ARM64_ERRATUM_2119858 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2224489 | ARM64_ERRATUM_2224489 | @@ -133,6 +139,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1349291 | N/A | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-N1 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2139208 | ARM64_ERRATUM_2139208 | @@ -141,6 +149,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2253138 | ARM64_ERRATUM_2253138 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-V1 | #1619801 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-500 | #841119,826419 | N/A | +----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-600 | #1076982,1209401| N/A |
Could these doc changes not go in patch 3?
As Suzuki had explained earlier, will keep this errata documentation here in this patch.
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 703b6fcbb6a5..1f3d29a639ff 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1150,6 +1150,31 @@ static void cpu_detect_trace_filtering(struct etmv4_drvdata *drvdata) drvdata->trfcr = trfcr; }
+/*
- The following errata on applicable cpu rangess affect the CCITMIN filed
s/rangess/ranges
Fixed.
- in TCRIDR3 register. Software read for the field returns 0x100 limiting
- the cycle threshold granularity, where as the right value should have
- been 0x4, which is well supported in the hardware.
- */
+static struct midr_range etm_wrong_ccitmin_cpus[] = {
/* Erratum #1490853 - Cortex-A76 */MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 4, 0),/* Erratum #1490853 - Neoverse-N1 */MIDR_RANGE(MIDR_NEOVERSE_N1, 0, 0, 4, 0),/* Erratum #1491015 - Cortex-A77 */MIDR_RANGE(MIDR_CORTEX_A77, 0, 0, 1, 0),/* Erratum #1502854 - Cortex-X1 */MIDR_REV(MIDR_CORTEX_X1, 0, 0),/* Erratum #1619801 - Neoverse-V1 */MIDR_REV(MIDR_NEOVERSE_V1, 0, 0),{},+};
+static bool etm4_work_around_wrong_ccitmin(void)
This is not the actual work around - perhaps this should be etm4_core_reads_wrong_ccitmin()?
Sounds better, will rename the function.
+{
return is_midr_in_range_list(read_cpuid_id(), etm_wrong_ccitmin_cpus);+}
static void etm4_init_arch_data(void *info) { u32 etmidr0; @@ -1214,6 +1239,18 @@ static void etm4_init_arch_data(void *info) etmidr3 = etm4x_relaxed_read32(csa, TRCIDR3); /* CCITMIN, bits[11:0] minimum threshold value that can be programmed */ drvdata->ccitmin = FIELD_GET(TRCIDR3_CCITMIN_MASK, etmidr3);
if (etm4_work_around_wrong_ccitmin()) {/** Erratum affected cpus will read 256 as the minimum* instruction trace cycle counting threshold where as* the correct value should be 4 instead. Override the* recorded value for 'drvdata->ccitmin' to workaround* this problem.*/if (drvdata->ccitmin == 256)Not sure this check matters - fixed cores will be 4, non fixed cores as identified by the list need to be 4, we don't care what the read value is if the core is on the list.
As discussed earlier, will keep this unchanged.
drvdata->ccitmin = 4;}/* EXLEVEL_S, bits[19:16] Secure state instruction tracing */ drvdata->s_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_S_MASK, etmidr3); drvdata->config.s_ex_level = drvdata->s_ex_level;-- 2.25.1
Regards
Mike
On 18/08/2023 09:45, Anshuman Khandual wrote:
On 8/11/23 14:33, Mike Leach wrote:
Hi Anshuman,
A few minor points.
On Fri, 11 Aug 2023 at 04:46, Anshuman Khandual anshuman.khandual@arm.com wrote:
This work arounds errata 1490853 on Cortex-A76, and Neoverse-N1, errata 1491015 on Cortex-A77, errata 1502854 on Cortex-X1, and errata 1619801 on Neoverse-V1, based affected cpus, where software read for TRCIDR3.CCITMIN field in ETM gets an wrong value.
If software uses the value returned by the TRCIDR3.CCITMIN register field, then it will limit the range which could be used for programming the ETM. In reality, the ETM could be programmed with a much smaller value than what is indicated by the TRCIDR3.CCITMIN field and still function correctly.
If software reads the TRCIDR3.CCITMIN register field, corresponding to the instruction trace counting minimum threshold, observe the value 0x100 or a minimum cycle count threshold of 256. The correct value should be 0x4 or a minimum cycle count threshold of 4.
This work arounds the problem via storing 4 in drvdata->ccitmin on affected systems where the TRCIDR3.CCITMIN has been 256, thus preserving cycle count threshold granularity.
These errata information has been updated in arch/arm64/silicon-errata.rst, but without their corresponding configs because these have been implemented directly in the driver.
Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will@kernel.org Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Jonathan Corbet corbet@lwn.net Cc: linux-doc@vger.kernel.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com
Documentation/arch/arm64/silicon-errata.rst | 10 +++++ .../coresight/coresight-etm4x-core.c | 37 +++++++++++++++++++ 2 files changed, 47 insertions(+)
diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst index bedd3a1d7b42..b08f33eda5f1 100644 --- a/Documentation/arch/arm64/silicon-errata.rst +++ b/Documentation/arch/arm64/silicon-errata.rst @@ -107,6 +107,10 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A76 | #1463225 | ARM64_ERRATUM_1463225 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A76 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A77 | #1491015 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A77 | #1508412 | ARM64_ERRATUM_1508412 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A510 | #2051678 | ARM64_ERRATUM_2051678 | @@ -125,6 +129,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A715 | #2645198 | ARM64_ERRATUM_2645198 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-X1 | #1502854 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2119858 | ARM64_ERRATUM_2119858 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2224489 | ARM64_ERRATUM_2224489 | @@ -133,6 +139,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1349291 | N/A | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-N1 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2139208 | ARM64_ERRATUM_2139208 | @@ -141,6 +149,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2253138 | ARM64_ERRATUM_2253138 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-V1 | #1619801 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-500 | #841119,826419 | N/A | +----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-600 | #1076982,1209401| N/A |
Could these doc changes not go in patch 3?
As Suzuki had explained earlier, will keep this errata documentation here in this patch.
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 703b6fcbb6a5..1f3d29a639ff 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1150,6 +1150,31 @@ static void cpu_detect_trace_filtering(struct etmv4_drvdata *drvdata) drvdata->trfcr = trfcr; }
+/*
- The following errata on applicable cpu rangess affect the CCITMIN filed
s/rangess/ranges
Fixed.
- in TCRIDR3 register. Software read for the field returns 0x100 limiting
- the cycle threshold granularity, where as the right value should have
- been 0x4, which is well supported in the hardware.
- */
+static struct midr_range etm_wrong_ccitmin_cpus[] = {
/* Erratum #1490853 - Cortex-A76 */MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 4, 0),/* Erratum #1490853 - Neoverse-N1 */MIDR_RANGE(MIDR_NEOVERSE_N1, 0, 0, 4, 0),/* Erratum #1491015 - Cortex-A77 */MIDR_RANGE(MIDR_CORTEX_A77, 0, 0, 1, 0),/* Erratum #1502854 - Cortex-X1 */MIDR_REV(MIDR_CORTEX_X1, 0, 0),/* Erratum #1619801 - Neoverse-V1 */MIDR_REV(MIDR_NEOVERSE_V1, 0, 0),{},+};
+static bool etm4_work_around_wrong_ccitmin(void)
This is not the actual work around - perhaps this should be etm4_core_reads_wrong_ccitmin()?
Sounds better, will rename the function.
Or even move the drvdata->ccitmin == 256 check to this function, pass in the drvdata as an argument. That way, the function completes its meaning. i.e., it reads wrong value only if the value is 256.
Suzuki
On 8/18/23 14:20, Suzuki K Poulose wrote:
On 18/08/2023 09:45, Anshuman Khandual wrote:
On 8/11/23 14:33, Mike Leach wrote:
Hi Anshuman,
A few minor points.
On Fri, 11 Aug 2023 at 04:46, Anshuman Khandual anshuman.khandual@arm.com wrote:
This work arounds errata 1490853 on Cortex-A76, and Neoverse-N1, errata 1491015 on Cortex-A77, errata 1502854 on Cortex-X1, and errata 1619801 on Neoverse-V1, based affected cpus, where software read for TRCIDR3.CCITMIN field in ETM gets an wrong value.
If software uses the value returned by the TRCIDR3.CCITMIN register field, then it will limit the range which could be used for programming the ETM. In reality, the ETM could be programmed with a much smaller value than what is indicated by the TRCIDR3.CCITMIN field and still function correctly.
If software reads the TRCIDR3.CCITMIN register field, corresponding to the instruction trace counting minimum threshold, observe the value 0x100 or a minimum cycle count threshold of 256. The correct value should be 0x4 or a minimum cycle count threshold of 4.
This work arounds the problem via storing 4 in drvdata->ccitmin on affected systems where the TRCIDR3.CCITMIN has been 256, thus preserving cycle count threshold granularity.
These errata information has been updated in arch/arm64/silicon-errata.rst, but without their corresponding configs because these have been implemented directly in the driver.
Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will@kernel.org Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Jonathan Corbet corbet@lwn.net Cc: linux-doc@vger.kernel.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com
Documentation/arch/arm64/silicon-errata.rst | 10 +++++ .../coresight/coresight-etm4x-core.c | 37 +++++++++++++++++++ 2 files changed, 47 insertions(+)
diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst index bedd3a1d7b42..b08f33eda5f1 100644 --- a/Documentation/arch/arm64/silicon-errata.rst +++ b/Documentation/arch/arm64/silicon-errata.rst @@ -107,6 +107,10 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A76 | #1463225 | ARM64_ERRATUM_1463225 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A76 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A77 | #1491015 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A77 | #1508412 | ARM64_ERRATUM_1508412 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A510 | #2051678 | ARM64_ERRATUM_2051678 | @@ -125,6 +129,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A715 | #2645198 | ARM64_ERRATUM_2645198 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-X1 | #1502854 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2119858 | ARM64_ERRATUM_2119858 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2224489 | ARM64_ERRATUM_2224489 | @@ -133,6 +139,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1349291 | N/A | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-N1 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2139208 | ARM64_ERRATUM_2139208 | @@ -141,6 +149,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2253138 | ARM64_ERRATUM_2253138 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-V1 | #1619801 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-500 | #841119,826419 | N/A | +----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-600 | #1076982,1209401| N/A |
Could these doc changes not go in patch 3?
As Suzuki had explained earlier, will keep this errata documentation here in this patch.
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 703b6fcbb6a5..1f3d29a639ff 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1150,6 +1150,31 @@ static void cpu_detect_trace_filtering(struct etmv4_drvdata *drvdata) drvdata->trfcr = trfcr; }
+/*
- The following errata on applicable cpu rangess affect the CCITMIN filed
s/rangess/ranges
Fixed.
- in TCRIDR3 register. Software read for the field returns 0x100 limiting
- the cycle threshold granularity, where as the right value should have
- been 0x4, which is well supported in the hardware.
- */
+static struct midr_range etm_wrong_ccitmin_cpus[] = { + /* Erratum #1490853 - Cortex-A76 */ + MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 4, 0), + /* Erratum #1490853 - Neoverse-N1 */ + MIDR_RANGE(MIDR_NEOVERSE_N1, 0, 0, 4, 0), + /* Erratum #1491015 - Cortex-A77 */ + MIDR_RANGE(MIDR_CORTEX_A77, 0, 0, 1, 0), + /* Erratum #1502854 - Cortex-X1 */ + MIDR_REV(MIDR_CORTEX_X1, 0, 0), + /* Erratum #1619801 - Neoverse-V1 */ + MIDR_REV(MIDR_NEOVERSE_V1, 0, 0), + {}, +};
+static bool etm4_work_around_wrong_ccitmin(void)
This is not the actual work around - perhaps this should be etm4_core_reads_wrong_ccitmin()?
Sounds better, will rename the function.
Or even move the drvdata->ccitmin == 256 check to this function, pass in the drvdata as an argument. That way, the function completes its meaning. i.e., it reads wrong value only if the value is 256.
Something like the following ?
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1159,9 +1159,20 @@ static struct midr_range etm_wrong_ccitmin_cpus[] = { {}, };
-static bool etm4_core_reads_wrong_ccitmin(void) +static bool etm4_core_reads_wrong_ccitmin(struct etmv4_drvdata *drvdata) { - return is_midr_in_range_list(read_cpuid_id(), etm_wrong_ccitmin_cpus); + if (is_midr_in_range_list(read_cpuid_id(), etm_wrong_ccitmin_cpus)) { + /* + * Erratum affected cpus will read 256 as the minimum + * instruction trace cycle counting threshold where as + * the correct value should be 4 instead. Override the + * recorded value for 'drvdata->ccitmin' to workaround + * this problem. + */ + if (drvdata->ccitmin == 256) + return true; + } + return false; }
static void etm4_init_arch_data(void *info) @@ -1228,17 +1239,8 @@ static void etm4_init_arch_data(void *info) etmidr3 = etm4x_relaxed_read32(csa, TRCIDR3); /* CCITMIN, bits[11:0] minimum threshold value that can be programmed */ drvdata->ccitmin = FIELD_GET(TRCIDR3_CCITMIN_MASK, etmidr3); - if (etm4_core_reads_wrong_ccitmin()) { - /* - * Erratum affected cpus will read 256 as the minimum - * instruction trace cycle counting threshold where as - * the correct value should be 4 instead. Override the - * recorded value for 'drvdata->ccitmin' to workaround - * this problem. - */ - if (drvdata->ccitmin == 256) - drvdata->ccitmin = 4; - } + if (etm4_core_reads_wrong_ccitmin(drvdata)) + drvdata->ccitmin = 4;
/* EXLEVEL_S, bits[19:16] Secure state instruction tracing */ drvdata->s_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_S_MASK, etmidr3);
Cycle counting is enabled, when requested and supported but with a default threshold value ETM_CYC_THRESHOLD_DEFAULT i.e 0x100 getting into TRCCCCTLR, representing the minimum interval between cycle count trace packets.
This makes cycle threshold user configurable, from the user space via perf event attributes. Although it falls back using ETM_CYC_THRESHOLD_DEFAULT, in case no explicit request. As expected it creates a sysfs file as well.
/sys/bus/event_source/devices/cs_etm/format/cc_threshold
New 'cc_threshold' uses 'event->attr.config3' as no more space is available in 'event->attr.config1' or 'event->attr.config2'.
Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Leo Yan leo.yan@linaro.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com --- drivers/hwtracing/coresight/coresight-etm-perf.c | 2 ++ drivers/hwtracing/coresight/coresight-etm4x-core.c | 12 ++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 5ca6278baff4..09f75dffae60 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -68,6 +68,7 @@ PMU_FORMAT_ATTR(preset, "config:0-3"); PMU_FORMAT_ATTR(sinkid, "config2:0-31"); /* config ID - set if a system configuration is selected */ PMU_FORMAT_ATTR(configid, "config2:32-63"); +PMU_FORMAT_ATTR(cc_threshold, "config3:0-11");
/* @@ -101,6 +102,7 @@ static struct attribute *etm_config_formats_attr[] = { &format_attr_preset.attr, &format_attr_configid.attr, &format_attr_branch_broadcast.attr, + &format_attr_cc_threshold.attr, NULL, };
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 1f3d29a639ff..ad28ee044cba 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -644,7 +644,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, struct etmv4_config *config = &drvdata->config; struct perf_event_attr *attr = &event->attr; unsigned long cfg_hash; - int preset; + int preset, cc_threshold;
/* Clear configuration from previous run */ memset(config, 0, sizeof(struct etmv4_config)); @@ -667,7 +667,15 @@ static int etm4_parse_event_config(struct coresight_device *csdev, if (attr->config & BIT(ETM_OPT_CYCACC)) { config->cfg |= TRCCONFIGR_CCI; /* TRM: Must program this for cycacc to work */ - config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT; + cc_threshold = attr->config3 & ETM_CYC_THRESHOLD_MASK; + if (cc_threshold) { + if (cc_threshold < drvdata->ccitmin) + config->ccctlr = drvdata->ccitmin; + else + config->ccctlr = cc_threshold; + } else { + config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT; + } } if (attr->config & BIT(ETM_OPT_TS)) { /*
On Fri, 11 Aug 2023 at 04:46, Anshuman Khandual anshuman.khandual@arm.com wrote:
Cycle counting is enabled, when requested and supported but with a default threshold value ETM_CYC_THRESHOLD_DEFAULT i.e 0x100 getting into TRCCCCTLR, representing the minimum interval between cycle count trace packets.
This makes cycle threshold user configurable, from the user space via perf event attributes. Although it falls back using ETM_CYC_THRESHOLD_DEFAULT, in case no explicit request. As expected it creates a sysfs file as well.
/sys/bus/event_source/devices/cs_etm/format/cc_threshold
New 'cc_threshold' uses 'event->attr.config3' as no more space is available in 'event->attr.config1' or 'event->attr.config2'.
Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Leo Yan leo.yan@linaro.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com
drivers/hwtracing/coresight/coresight-etm-perf.c | 2 ++ drivers/hwtracing/coresight/coresight-etm4x-core.c | 12 ++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 5ca6278baff4..09f75dffae60 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -68,6 +68,7 @@ PMU_FORMAT_ATTR(preset, "config:0-3"); PMU_FORMAT_ATTR(sinkid, "config2:0-31"); /* config ID - set if a system configuration is selected */ PMU_FORMAT_ATTR(configid, "config2:32-63"); +PMU_FORMAT_ATTR(cc_threshold, "config3:0-11");
/* @@ -101,6 +102,7 @@ static struct attribute *etm_config_formats_attr[] = { &format_attr_preset.attr, &format_attr_configid.attr, &format_attr_branch_broadcast.attr,
&format_attr_cc_threshold.attr, NULL,};
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 1f3d29a639ff..ad28ee044cba 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -644,7 +644,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, struct etmv4_config *config = &drvdata->config; struct perf_event_attr *attr = &event->attr; unsigned long cfg_hash;
int preset;
int preset, cc_threshold; /* Clear configuration from previous run */ memset(config, 0, sizeof(struct etmv4_config));@@ -667,7 +667,15 @@ static int etm4_parse_event_config(struct coresight_device *csdev, if (attr->config & BIT(ETM_OPT_CYCACC)) { config->cfg |= TRCCONFIGR_CCI; /* TRM: Must program this for cycacc to work */
config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT;
cc_threshold = attr->config3 & ETM_CYC_THRESHOLD_MASK;if (cc_threshold) {if (cc_threshold < drvdata->ccitmin)config->ccctlr = drvdata->ccitmin;elseconfig->ccctlr = cc_threshold;} else {config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT;
Don't normally have {} round a single statement else clause - did checkpatch.pl not object here?
Otherwise
Reviewed-by: Mike Leach mike.leach@linaro.org
} } if (attr->config & BIT(ETM_OPT_TS)) { /*-- 2.25.1
On 8/11/23 14:22, Mike Leach wrote:
On Fri, 11 Aug 2023 at 04:46, Anshuman Khandual anshuman.khandual@arm.com wrote:
Cycle counting is enabled, when requested and supported but with a default threshold value ETM_CYC_THRESHOLD_DEFAULT i.e 0x100 getting into TRCCCCTLR, representing the minimum interval between cycle count trace packets.
This makes cycle threshold user configurable, from the user space via perf event attributes. Although it falls back using ETM_CYC_THRESHOLD_DEFAULT, in case no explicit request. As expected it creates a sysfs file as well.
/sys/bus/event_source/devices/cs_etm/format/cc_threshold
New 'cc_threshold' uses 'event->attr.config3' as no more space is available in 'event->attr.config1' or 'event->attr.config2'.
Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Leo Yan leo.yan@linaro.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com
drivers/hwtracing/coresight/coresight-etm-perf.c | 2 ++ drivers/hwtracing/coresight/coresight-etm4x-core.c | 12 ++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 5ca6278baff4..09f75dffae60 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -68,6 +68,7 @@ PMU_FORMAT_ATTR(preset, "config:0-3"); PMU_FORMAT_ATTR(sinkid, "config2:0-31"); /* config ID - set if a system configuration is selected */ PMU_FORMAT_ATTR(configid, "config2:32-63"); +PMU_FORMAT_ATTR(cc_threshold, "config3:0-11");
/* @@ -101,6 +102,7 @@ static struct attribute *etm_config_formats_attr[] = { &format_attr_preset.attr, &format_attr_configid.attr, &format_attr_branch_broadcast.attr,
&format_attr_cc_threshold.attr, NULL,};
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 1f3d29a639ff..ad28ee044cba 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -644,7 +644,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, struct etmv4_config *config = &drvdata->config; struct perf_event_attr *attr = &event->attr; unsigned long cfg_hash;
int preset;
int preset, cc_threshold; /* Clear configuration from previous run */ memset(config, 0, sizeof(struct etmv4_config));@@ -667,7 +667,15 @@ static int etm4_parse_event_config(struct coresight_device *csdev, if (attr->config & BIT(ETM_OPT_CYCACC)) { config->cfg |= TRCCONFIGR_CCI; /* TRM: Must program this for cycacc to work */
config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT;
cc_threshold = attr->config3 & ETM_CYC_THRESHOLD_MASK;if (cc_threshold) {if (cc_threshold < drvdata->ccitmin)config->ccctlr = drvdata->ccitmin;elseconfig->ccctlr = cc_threshold;} else {config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT;Don't normally have {} round a single statement else clause - did
I would believe single statement else clause could have { }, only when the preceding if clause consists of multiple statements just to be symmetrical ?
checkpatch.pl not object here?
No, it does not object.
Otherwise
Reviewed-by: Mike Leach mike.leach@linaro.org
} } if (attr->config & BIT(ETM_OPT_TS)) { /*-- 2.25.1
On Fri, 11 Aug 2023 at 09:57, Anshuman Khandual anshuman.khandual@arm.com wrote:
On 8/11/23 14:22, Mike Leach wrote:
On Fri, 11 Aug 2023 at 04:46, Anshuman Khandual anshuman.khandual@arm.com wrote:
Cycle counting is enabled, when requested and supported but with a default threshold value ETM_CYC_THRESHOLD_DEFAULT i.e 0x100 getting into TRCCCCTLR, representing the minimum interval between cycle count trace packets.
This makes cycle threshold user configurable, from the user space via perf event attributes. Although it falls back using ETM_CYC_THRESHOLD_DEFAULT, in case no explicit request. As expected it creates a sysfs file as well.
/sys/bus/event_source/devices/cs_etm/format/cc_threshold
New 'cc_threshold' uses 'event->attr.config3' as no more space is available in 'event->attr.config1' or 'event->attr.config2'.
Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Leo Yan leo.yan@linaro.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com
drivers/hwtracing/coresight/coresight-etm-perf.c | 2 ++ drivers/hwtracing/coresight/coresight-etm4x-core.c | 12 ++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 5ca6278baff4..09f75dffae60 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -68,6 +68,7 @@ PMU_FORMAT_ATTR(preset, "config:0-3"); PMU_FORMAT_ATTR(sinkid, "config2:0-31"); /* config ID - set if a system configuration is selected */ PMU_FORMAT_ATTR(configid, "config2:32-63"); +PMU_FORMAT_ATTR(cc_threshold, "config3:0-11");
/* @@ -101,6 +102,7 @@ static struct attribute *etm_config_formats_attr[] = { &format_attr_preset.attr, &format_attr_configid.attr, &format_attr_branch_broadcast.attr,
&format_attr_cc_threshold.attr, NULL,};
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 1f3d29a639ff..ad28ee044cba 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -644,7 +644,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, struct etmv4_config *config = &drvdata->config; struct perf_event_attr *attr = &event->attr; unsigned long cfg_hash;
int preset;
int preset, cc_threshold; /* Clear configuration from previous run */ memset(config, 0, sizeof(struct etmv4_config));@@ -667,7 +667,15 @@ static int etm4_parse_event_config(struct coresight_device *csdev, if (attr->config & BIT(ETM_OPT_CYCACC)) { config->cfg |= TRCCONFIGR_CCI; /* TRM: Must program this for cycacc to work */
config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT;
cc_threshold = attr->config3 & ETM_CYC_THRESHOLD_MASK;if (cc_threshold) {if (cc_threshold < drvdata->ccitmin)config->ccctlr = drvdata->ccitmin;elseconfig->ccctlr = cc_threshold;} else {config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT;Don't normally have {} round a single statement else clause - did
I would believe single statement else clause could have { }, only when the preceding if clause consists of multiple statements just to be symmetrical ?
checkpatch.pl not object here?
No, it does not object.
Fair enough - good to go then!
Otherwise
Reviewed-by: Mike Leach mike.leach@linaro.org
} } if (attr->config & BIT(ETM_OPT_TS)) { /*-- 2.25.1
This updates config option to include 'cc_threshold' tunable value.
Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Jonathan Corbet corbet@lwn.net Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com --- Documentation/trace/coresight/coresight.rst | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst index 4a71ea6cb390..ce55adb80b82 100644 --- a/Documentation/trace/coresight/coresight.rst +++ b/Documentation/trace/coresight/coresight.rst @@ -624,6 +624,10 @@ They are also listed in the folder /sys/bus/event_source/devices/cs_etm/format/ * - timestamp - Session local version of the system wide setting: :ref:`ETMv4_MODE_TIMESTAMP <coresight-timestamp>` + * - cc_threshold + - Cycle count threshold value. If nothing is provided here or the provided value is 0, then the + default value i.e 0x100 will be used. If provided value is less than minimum cycles threshold + value, as indicated via TRCIDR3.CCITMIN, then the minimum value will be used instead.
How to use the STM module -------------------------
On Fri, 11 Aug 2023 at 04:46, Anshuman Khandual anshuman.khandual@arm.com wrote:
This updates config option to include 'cc_threshold' tunable value.
Cc: Suzuki K Poulose suzuki.poulose@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Jonathan Corbet corbet@lwn.net Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com
Documentation/trace/coresight/coresight.rst | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst index 4a71ea6cb390..ce55adb80b82 100644 --- a/Documentation/trace/coresight/coresight.rst +++ b/Documentation/trace/coresight/coresight.rst @@ -624,6 +624,10 @@ They are also listed in the folder /sys/bus/event_source/devices/cs_etm/format/ * - timestamp - Session local version of the system wide setting: :ref:`ETMv4_MODE_TIMESTAMP <coresight-timestamp>`
- cc_threshold
- Cycle count threshold value. If nothing is provided here or the provided value is 0, then thedefault value i.e 0x100 will be used. If provided value is less than minimum cycles thresholdvalue, as indicated via TRCIDR3.CCITMIN, then the minimum value will be used instead.How to use the STM module
-- 2.25.1
Reviewed by: Mike Leach mike.leach@linaro.org
-
Anshuman Khandual -
Mike Leach -
Suzuki K Poulose