[PATCH v3 03/10] perf: arm_spe: Add support for FEAT_SPE_EFT extended filtering

James Clark
2025-06-05T10:59:41Z

FEAT_SPE_EFT (optional from Armv9.4) adds mask bits for the existing
load, store and branch filters. It also adds two new filter bits for
SIMD and floating point with their own associated mask bits. The current
filters only allow OR filtering on samples that are load OR store etc,
and the new mask bits allow setting part of the filter to an AND, for
example filtering samples that are store AND SIMD. With mask bits set to
0, the OR behavior is preserved, so the unless any masks are explicitly
set old filters will behave the same.

Add them all and make them behave the same way as existing format bits,
hidden and return EOPNOTSUPP if set when the feature doesn't exist.

Reviewed-by: Leo Yan <leo.yan@arm.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: James Clark <james.clark@linaro.org>
---
drivers/perf/arm_spe_pmu.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)

diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
index d9f6d229dce8..9309b846f642 100644
--- a/drivers/perf/arm_spe_pmu.c
+++ b/drivers/perf/arm_spe_pmu.c
@@ -86,6 +86,7 @@ struct arm_spe_pmu {
#define SPE_PMU_FEAT_ERND (1UL << 5)
#define SPE_PMU_FEAT_INV_FILT_EVT (1UL << 6)
#define SPE_PMU_FEAT_DISCARD (1UL << 7)
+#define SPE_PMU_FEAT_EFT (1UL << 8)
#define SPE_PMU_FEAT_DEV_PROBED (1UL << 63)
u64 features;

@@ -197,6 +198,27 @@ static const struct attribute_group arm_spe_pmu_cap_group = {
#define ATTR_CFG_FLD_discard_CFG config /* PMBLIMITR_EL1.FM = DISCARD */
#define ATTR_CFG_FLD_discard_LO 35
#define ATTR_CFG_FLD_discard_HI 35
+#define ATTR_CFG_FLD_branch_filter_mask_CFG config /* PMSFCR_EL1.Bm */
+#define ATTR_CFG_FLD_branch_filter_mask_LO 36
+#define ATTR_CFG_FLD_branch_filter_mask_HI 36
+#define ATTR_CFG_FLD_load_filter_mask_CFG config /* PMSFCR_EL1.LDm */
+#define ATTR_CFG_FLD_load_filter_mask_LO 37
+#define ATTR_CFG_FLD_load_filter_mask_HI 37
+#define ATTR_CFG_FLD_store_filter_mask_CFG config /* PMSFCR_EL1.STm */
+#define ATTR_CFG_FLD_store_filter_mask_LO 38
+#define ATTR_CFG_FLD_store_filter_mask_HI 38
+#define ATTR_CFG_FLD_simd_filter_CFG config /* PMSFCR_EL1.SIMD */
+#define ATTR_CFG_FLD_simd_filter_LO 39
+#define ATTR_CFG_FLD_simd_filter_HI 39
+#define ATTR_CFG_FLD_simd_filter_mask_CFG config /* PMSFCR_EL1.SIMDm */
+#define ATTR_CFG_FLD_simd_filter_mask_LO 40
+#define ATTR_CFG_FLD_simd_filter_mask_HI 40
+#define ATTR_CFG_FLD_float_filter_CFG config /* PMSFCR_EL1.FP */
+#define ATTR_CFG_FLD_float_filter_LO 41
+#define ATTR_CFG_FLD_float_filter_HI 41
+#define ATTR_CFG_FLD_float_filter_mask_CFG config /* PMSFCR_EL1.FPm */
+#define ATTR_CFG_FLD_float_filter_mask_LO 42
+#define ATTR_CFG_FLD_float_filter_mask_HI 42

#define ATTR_CFG_FLD_event_filter_CFG config1 /* PMSEVFR_EL1 */
#define ATTR_CFG_FLD_event_filter_LO 0
@@ -215,8 +237,15 @@ GEN_PMU_FORMAT_ATTR(pa_enable);
GEN_PMU_FORMAT_ATTR(pct_enable);
GEN_PMU_FORMAT_ATTR(jitter);
GEN_PMU_FORMAT_ATTR(branch_filter);
+GEN_PMU_FORMAT_ATTR(branch_filter_mask);
GEN_PMU_FORMAT_ATTR(load_filter);
+GEN_PMU_FORMAT_ATTR(load_filter_mask);
GEN_PMU_FORMAT_ATTR(store_filter);
+GEN_PMU_FORMAT_ATTR(store_filter_mask);
+GEN_PMU_FORMAT_ATTR(simd_filter);
+GEN_PMU_FORMAT_ATTR(simd_filter_mask);
+GEN_PMU_FORMAT_ATTR(float_filter);
+GEN_PMU_FORMAT_ATTR(float_filter_mask);
GEN_PMU_FORMAT_ATTR(event_filter);
GEN_PMU_FORMAT_ATTR(inv_event_filter);
GEN_PMU_FORMAT_ATTR(min_latency);
@@ -228,8 +257,15 @@ static struct attribute *arm_spe_pmu_formats_attr[] = {
&format_attr_pct_enable.attr,
&format_attr_jitter.attr,
&format_attr_branch_filter.attr,
+ &format_attr_branch_filter_mask.attr,
&format_attr_load_filter.attr,
+ &format_attr_load_filter_mask.attr,
&format_attr_store_filter.attr,
+ &format_attr_store_filter_mask.attr,
+ &format_attr_simd_filter.attr,
+ &format_attr_simd_filter_mask.attr,
+ &format_attr_float_filter.attr,
+ &format_attr_float_filter_mask.attr,
&format_attr_event_filter.attr,
&format_attr_inv_event_filter.attr,
&format_attr_min_latency.attr,
@@ -250,6 +286,16 @@ static umode_t arm_spe_pmu_format_attr_is_visible(struct kobject *kobj,
if (attr == &format_attr_inv_event_filter.attr && !(spe_pmu->features & SPE_PMU_FEAT_INV_FILT_EVT))
return 0;

+ if ((attr == &format_attr_branch_filter_mask.attr ||
+ attr == &format_attr_load_filter_mask.attr ||
+ attr == &format_attr_store_filter_mask.attr ||
+ attr == &format_attr_simd_filter.attr ||
+ attr == &format_attr_simd_filter_mask.attr ||
+ attr == &format_attr_float_filter.attr ||
+ attr == &format_attr_float_filter_mask.attr) &&
+ !(spe_pmu->features & SPE_PMU_FEAT_EFT))
+ return 0;
+
return attr->mode;
}

@@ -341,8 +387,15 @@ static u64 arm_spe_event_to_pmsfcr(struct perf_event *event)
u64 reg = 0;

reg |= FIELD_PREP(PMSFCR_EL1_LD, ATTR_CFG_GET_FLD(attr, load_filter));
+ reg |= FIELD_PREP(PMSFCR_EL1_LDm, ATTR_CFG_GET_FLD(attr, load_filter_mask));
reg |= FIELD_PREP(PMSFCR_EL1_ST, ATTR_CFG_GET_FLD(attr, store_filter));
+ reg |= FIELD_PREP(PMSFCR_EL1_STm, ATTR_CFG_GET_FLD(attr, store_filter_mask));
reg |= FIELD_PREP(PMSFCR_EL1_B, ATTR_CFG_GET_FLD(attr, branch_filter));
+ reg |= FIELD_PREP(PMSFCR_EL1_Bm, ATTR_CFG_GET_FLD(attr, branch_filter_mask));
+ reg |= FIELD_PREP(PMSFCR_EL1_SIMD, ATTR_CFG_GET_FLD(attr, simd_filter));
+ reg |= FIELD_PREP(PMSFCR_EL1_SIMDm, ATTR_CFG_GET_FLD(attr, simd_filter_mask));
+ reg |= FIELD_PREP(PMSFCR_EL1_FP, ATTR_CFG_GET_FLD(attr, float_filter));
+ reg |= FIELD_PREP(PMSFCR_EL1_FPm, ATTR_CFG_GET_FLD(attr, float_filter_mask));

if (reg)
reg |= PMSFCR_EL1_FT;
@@ -716,6 +769,10 @@ static int arm_spe_pmu_event_init(struct perf_event *event)
u64 reg;
struct perf_event_attr *attr = &event->attr;
struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
+ const u64 feat_spe_eft_bits = PMSFCR_EL1_LDm | PMSFCR_EL1_STm |
+ PMSFCR_EL1_Bm | PMSFCR_EL1_SIMD |
+ PMSFCR_EL1_SIMDm | PMSFCR_EL1_FP |
+ PMSFCR_EL1_FPm;

/* This is, of course, deeply driver-specific */
if (attr->type != event->pmu->type)
@@ -761,6 +818,10 @@ static int arm_spe_pmu_event_init(struct perf_event *event)
!(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT))
return -EOPNOTSUPP;

+ if ((reg & feat_spe_eft_bits) &&
+ !(spe_pmu->features & SPE_PMU_FEAT_EFT))
+ return -EOPNOTSUPP;
+
if (ATTR_CFG_GET_FLD(&event->attr, discard) &&
!(spe_pmu->features & SPE_PMU_FEAT_DISCARD))
return -EOPNOTSUPP;
@@ -1052,6 +1113,9 @@ static void __arm_spe_pmu_dev_probe(void *info)
if (spe_pmu->pmsver >= ID_AA64DFR0_EL1_PMSVer_V1P2)
spe_pmu->features |= SPE_PMU_FEAT_DISCARD;

+ if (FIELD_GET(PMSIDR_EL1_EFT, reg))
+ spe_pmu->features |= SPE_PMU_FEAT_EFT;
+
/* This field has a spaced out encoding, so just use a look-up */
fld = FIELD_GET(PMSIDR_EL1_INTERVAL, reg);
switch (fld) {

--
2.34.1