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 <[email protected]>
---
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
On Fri, Aug 04, 2023 at 09:52:17AM +0100, James Clark wrote:
> +
> +Sysreg TRFCR_EL12 3 5 1 2 1
> +Fields TRFCR_ELx
> +EndSysreg
This bit checks out against DDI0601 2023-06:
Reviewed-by: Mark Brown <[email protected]> (sysreg)