[PATCH 2/2] coresight: Allow guests to be traced when FEAT_TRF and VHE are present
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SUPERSEDED
From: James Clark <hidden>
Date: 2023-08-04 08:59:08
Also in:
lkml
Subsystem:
arm/coresight framework and drivers, arm64 port (aarch64 architecture), hardware tracing facilities, the rest · Maintainers:
Suzuki K Poulose, Catalin Marinas, Will Deacon, Alexander Shishkin, Linus Torvalds
Revision v1 of 3 in this series.
Revisions (3)
- v1 current
- v2 [diff vs current]
- v3 [diff vs current]
Currently the userspace and kernel filters for guests are never set, so
no trace will be generated for them. Add it by writing to the guest
filters when exclude_guest isn't set. By writing either E1TRE or E0TRE,
filtering on either guest kernel or guest userspace is also supported.
Since TRFCR_EL1 access is trapped, this can't be modified by the guest.
This change also brings exclude_host support which is difficult to add
as a separate commit without excess churn and resulting in no trace at
all.
Testing
=======
The addresses were counted with the following:
$ perf report -D | grep -Eo 'EL2|EL1|EL0' | sort | uniq -c
Guest kernel only:
$ perf record -e cs_etm//Gk -a -- true
535 EL1
1 EL2
Guest user only (0 addresses expected because the guest OS hasn't reached
userspace yet):
$ perf record -e cs_etm//Gu -a -- true
Host kernel only:
$ perf record -e cs_etm//Hk -a -- true
3501 EL2
Host userspace only:
$ perf record -e cs_etm//Hu -a -- true
408 EL0
1 EL2
Signed-off-by: James Clark <redacted>
---
arch/arm64/tools/sysreg | 4 ++
.../coresight/coresight-etm4x-core.c | 45 ++++++++++++++++---
drivers/hwtracing/coresight/coresight-etm4x.h | 2 +-
drivers/hwtracing/coresight/coresight-priv.h | 3 ++
4 files changed, 47 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index fe1f824977d9..81028ef08415 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg@@ -2517,3 +2517,7 @@ EndSysreg Sysreg TRFCR_EL2 3 4 1 2 1 Fields TRFCR_ELx EndSysreg + +Sysreg TRFCR_EL12 3 5 1 2 1 +Fields TRFCR_ELx +EndSysreg
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 257e5c1a4b52..8c0356ec905e 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c@@ -274,6 +274,18 @@ static void etm4x_prohibit_trace(struct etmv4_drvdata *drvdata) cpu_prohibit_trace(); } +static u64 etm4x_get_kern_user_filter(struct etmv4_drvdata *drvdata) +{ + u64 trfcr = drvdata->trfcr; + + if (drvdata->config.mode & ETM_MODE_EXCL_KERN) + trfcr &= ~TRFCR_ELx_ExTRE; + if (drvdata->config.mode & ETM_MODE_EXCL_USER) + trfcr &= ~TRFCR_ELx_E0TRE; + + return trfcr; +} + /* * etm4x_allow_trace - Allow CPU tracing in the respective ELs, * as configured by the drvdata->config.mode for the current
@@ -286,18 +298,33 @@ static void etm4x_prohibit_trace(struct etmv4_drvdata *drvdata) */ static void etm4x_allow_trace(struct etmv4_drvdata *drvdata) { - u64 trfcr = drvdata->trfcr; + u64 trfcr; /* If the CPU doesn't support FEAT_TRF, nothing to do */ - if (!trfcr) + if (!drvdata->trfcr) return; - if (drvdata->config.mode & ETM_MODE_EXCL_KERN) - trfcr &= ~TRFCR_ELx_ExTRE; - if (drvdata->config.mode & ETM_MODE_EXCL_USER) - trfcr &= ~TRFCR_ELx_E0TRE; + if (drvdata->config.mode & ETM_MODE_EXCL_HOST) + trfcr = drvdata->trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE); + else + trfcr = etm4x_get_kern_user_filter(drvdata); write_trfcr(trfcr); + + /* + * Filters for EL1 and EL0 (when running a guest) are stored in + * TRFCR_EL1 so write it there for VHE. For nVHE, the filters in + * have to be re-applied when switching to the guest instead. + */ + if (!is_kernel_in_hyp_mode()) + return; + + if (drvdata->config.mode & ETM_MODE_EXCL_GUEST) + trfcr = drvdata->trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE); + else + trfcr = etm4x_get_kern_user_filter(drvdata); + + write_sysreg_s(trfcr, SYS_TRFCR_EL12); } #ifdef CONFIG_ETM4X_IMPDEF_FEATURE
@@ -655,6 +682,12 @@ static int etm4_parse_event_config(struct coresight_device *csdev, if (attr->exclude_user) config->mode = ETM_MODE_EXCL_USER; + if (attr->exclude_host) + config->mode |= ETM_MODE_EXCL_HOST; + + if (attr->exclude_guest) + config->mode |= ETM_MODE_EXCL_GUEST; + /* Always start from the default config */ etm4_set_default_config(config);
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index 20e2e4cb7614..3f170599822f 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h@@ -841,7 +841,7 @@ enum etm_impdef_type { * @s_ex_level: Secure ELs where tracing is supported. */ struct etmv4_config { - u32 mode; + u64 mode; u32 pe_sel; u32 cfg; u32 eventctrl0;
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index 767076e07970..727dd27ba800 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h@@ -39,6 +39,9 @@ #define ETM_MODE_EXCL_KERN BIT(30) #define ETM_MODE_EXCL_USER BIT(31) +#define ETM_MODE_EXCL_HOST BIT(32) +#define ETM_MODE_EXCL_GUEST BIT(33) + struct cs_pair_attribute { struct device_attribute attr; u32 lo_off;
--
2.34.1
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