* [PATCH v2 1/3] lib: sbi_pmu: Return invalid param error for reserved event_idx bits
2026-08-18 21:00 ` [PATCH v2 0/3] lib: sbi_pmu: SBI v3.0 PMU error code fixes David E. Garcia Porras
@ 2026-08-18 21:00 ` David E. Garcia Porras
2026-08-18 21:00 ` [PATCH v2 2/3] lib: sbi_pmu: Match raw event selector only against raw event map entries David E. Garcia Porras
2026-08-18 21:00 ` [PATCH v2 3/3] lib: sbi_pmu: Fix counter and event info error codes as per SBI v3.0 spec David E. Garcia Porras
2 siblings, 0 replies; 5+ messages in thread
From: David E. Garcia Porras @ 2026-08-18 21:00 UTC (permalink / raw)
To: opensbi; +Cc: David E. Garcia Porras
As per section 11.14 of the SBI specification (Function: Get PMU Event
Info, FID #8), Table 47, the event_idx word of an event info entry
only uses BIT[0:19]; BIT[20:31] are reserved for the future purpose
and must be zero. Table 48 further requires the SBI implementation to
return SBI_ERR_INVALID_PARAM if any reserved bit in an event_idx word
is set.
sbi_pmu_event_get_info() does not check the reserved bits, so a
malformed event_idx is silently passed on to pmu_event_validate()
instead of failing the call. Add SBI_PMU_EVENT_IDX_MBZ_MASK covering
the must-be-zero bits and return SBI_ERR_INVALID_PARAM when any of
them are set.
Fixes: e4345842168b ("lib: sbi_pmu: Implement SBI PMU event info function")
Signed-off-by: David E. Garcia Porras <david.garcia@aheadcomputing.com>
---
include/sbi/sbi_ecall_interface.h | 2 ++
lib/sbi/sbi_pmu.c | 3 +++
2 files changed, 5 insertions(+)
diff --git a/include/sbi/sbi_ecall_interface.h b/include/sbi/sbi_ecall_interface.h
index acb91a01..bfde25d0 100644
--- a/include/sbi/sbi_ecall_interface.h
+++ b/include/sbi/sbi_ecall_interface.h
@@ -271,6 +271,8 @@ struct sbi_pmu_event_info {
#define SBI_PMU_EVENT_IDX_TYPE_OFFSET 16
#define SBI_PMU_EVENT_IDX_TYPE_MASK (0xF << SBI_PMU_EVENT_IDX_TYPE_OFFSET)
#define SBI_PMU_EVENT_IDX_CODE_MASK 0xFFFF
+#define SBI_PMU_EVENT_IDX_MBZ_OFFSET 20
+#define SBI_PMU_EVENT_IDX_MBZ_MASK (0xFFF << SBI_PMU_EVENT_IDX_MBZ_OFFSET)
#define SBI_PMU_EVENT_RAW_IDX 0x20000
#define SBI_PMU_EVENT_RAW_V2_IDX 0x30000
diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
index a0f6d2fa..4558876e 100644
--- a/lib/sbi/sbi_pmu.c
+++ b/lib/sbi/sbi_pmu.c
@@ -1098,6 +1098,9 @@ int sbi_pmu_event_get_info(unsigned long shmem_phys_lo, unsigned long shmem_phys
einfo = (struct sbi_pmu_event_info *)(shmem_phys_lo);
for (i = 0; i < num_events; i++) {
event_idx = einfo[i].event_idx;
+ /* Any must-be-zero event_idx bits set should return INVALID_PARAM per-spec */
+ if (event_idx & SBI_PMU_EVENT_IDX_MBZ_MASK)
+ return SBI_ERR_INVALID_PARAM;
event_type = pmu_event_validate(phs, event_idx, einfo[i].event_data);
if (event_type < 0) {
einfo[i].output = 0;
--
2.43.0
--
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^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v2 2/3] lib: sbi_pmu: Match raw event selector only against raw event map entries
2026-08-18 21:00 ` [PATCH v2 0/3] lib: sbi_pmu: SBI v3.0 PMU error code fixes David E. Garcia Porras
2026-08-18 21:00 ` [PATCH v2 1/3] lib: sbi_pmu: Return invalid param error for reserved event_idx bits David E. Garcia Porras
@ 2026-08-18 21:00 ` David E. Garcia Porras
2026-08-18 21:00 ` [PATCH v2 3/3] lib: sbi_pmu: Fix counter and event info error codes as per SBI v3.0 spec David E. Garcia Porras
2 siblings, 0 replies; 5+ messages in thread
From: David E. Garcia Porras @ 2026-08-18 21:00 UTC (permalink / raw)
To: opensbi; +Cc: David E. Garcia Porras
sbi_pmu_event_get_info() walks hw_event_map[] to decide whether a
requested event is supported. For SBI_PMU_EVENT_RAW_IDX and
SBI_PMU_EVENT_RAW_V2_IDX it compares the requested event_data against
temp->select / temp->select_mask without first checking that the map
entry being examined is itself a raw event entry.
Non-raw hardware event entries are added via sbi_pmu_add_hw_event_counter_map(),
leave select and select_mask at zero, hence they satisfy:
temp->select == (event_data & temp->select_mask)
so the first non-raw entry visited will always match.
The issue's observability depends purely on the ordering of hw_event_map[]:
if the platform registers its raw events last, every raw event query, including
unsupported ones, will be reported as supported.
Fix it by checking event_idx against temp->start_idx and temp->end_idx before comparing select/select_mask.
Fixes: e4345842168b ("lib: sbi_pmu: Implement SBI PMU event info function")
Signed-off-by: David E. Garcia Porras <david.garcia@aheadcomputing.com>
---
lib/sbi/sbi_pmu.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
index 4558876e..676de9aa 100644
--- a/lib/sbi/sbi_pmu.c
+++ b/lib/sbi/sbi_pmu.c
@@ -1110,6 +1110,15 @@ int sbi_pmu_event_get_info(unsigned long shmem_phys_lo, unsigned long shmem_phys
/* For raw events, event data is used as the select value */
if (event_idx == SBI_PMU_EVENT_RAW_IDX ||
event_idx == SBI_PMU_EVENT_RAW_V2_IDX) {
+ /*
+ * Only a raw event map entry carries a
+ * meaningful select/select_mask pair, so
+ * skip any entry which does not cover the
+ * raw event index.
+ */
+ if (temp->start_idx > event_idx ||
+ event_idx > temp->end_idx)
+ continue;
/* just match the selector */
if (temp->select == (einfo[i].event_data &
temp->select_mask)) {
--
2.43.0
--
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^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v2 3/3] lib: sbi_pmu: Fix counter and event info error codes as per SBI v3.0 spec
2026-08-18 21:00 ` [PATCH v2 0/3] lib: sbi_pmu: SBI v3.0 PMU error code fixes David E. Garcia Porras
2026-08-18 21:00 ` [PATCH v2 1/3] lib: sbi_pmu: Return invalid param error for reserved event_idx bits David E. Garcia Porras
2026-08-18 21:00 ` [PATCH v2 2/3] lib: sbi_pmu: Match raw event selector only against raw event map entries David E. Garcia Porras
@ 2026-08-18 21:00 ` David E. Garcia Porras
2 siblings, 0 replies; 5+ messages in thread
From: David E. Garcia Porras @ 2026-08-18 21:00 UTC (permalink / raw)
To: opensbi; +Cc: David E. Garcia Porras
Align the PMU extension implementation with the error codes required
by the SBI v3.0 specification, chapter 11:
- sbi_pmu_counter_start and sbi_pmu_counter_stop (secs 11.9-11.10,
tables 39-42): the start_flags/stop_flags bits 2:(XLEN-1) are
reserved and must be zero, so return SBI_ERR_INVALID_PARAM when any
reserved flag bit is set. Introduce SBI_PMU_START_FLAGS_MASK and
SBI_PMU_STOP_FLAGS_MASK for the valid bits of each function.
- sbi_pmu_counter_start and sbi_pmu_counter_stop (tables 40 and 42):
return SBI_ERR_ALREADY_STARTED / SBI_ERR_ALREADY_STOPPED when the
set of counters includes a counter which is already started or
stopped, instead of ignoring the error returned for each counter.
- sbi_pmu_event_get_info (sec 11.14, table 47): the output word must
indicate whether the event is supported, but firmware events were
only matched against the hardware event map and were always
reported as unsupported. Report a validated firmware event as
supported.
Signed-off-by: David E. Garcia Porras <david.garcia@aheadcomputing.com>
---
include/sbi/sbi_ecall_interface.h | 12 ++++++
lib/sbi/sbi_pmu.c | 61 ++++++++++++++++++++-----------
2 files changed, 52 insertions(+), 21 deletions(-)
diff --git a/include/sbi/sbi_ecall_interface.h b/include/sbi/sbi_ecall_interface.h
index bfde25d0..fd4e77ca 100644
--- a/include/sbi/sbi_ecall_interface.h
+++ b/include/sbi/sbi_ecall_interface.h
@@ -306,10 +306,22 @@ struct sbi_pmu_event_info {
/* Flags defined for counter start function */
#define SBI_PMU_START_FLAG_SET_INIT_VALUE (1 << 0)
#define SBI_PMU_START_FLAG_INIT_FROM_SNAPSHOT (1 << 1)
+/* Start flags valid mask */
+#define SBI_PMU_START_FLAGS_MASK \
+ ( \
+ SBI_PMU_START_FLAG_SET_INIT_VALUE | \
+ SBI_PMU_START_FLAG_INIT_FROM_SNAPSHOT \
+ )
/* Flags defined for counter stop function */
#define SBI_PMU_STOP_FLAG_RESET (1 << 0)
#define SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT (1 << 1)
+/* Stop flags valid mask */
+#define SBI_PMU_STOP_FLAGS_MASK \
+ ( \
+ SBI_PMU_STOP_FLAG_RESET | \
+ SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT \
+ )
/* SBI function IDs for DBCN extension */
#define SBI_EXT_DBCN_CONSOLE_WRITE 0x0
diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
index 676de9aa..0c62bde0 100644
--- a/lib/sbi/sbi_pmu.c
+++ b/lib/sbi/sbi_pmu.c
@@ -574,6 +574,9 @@ int sbi_pmu_ctr_start(unsigned long cbase, unsigned long cmask,
if (!pmu_ctr_idx_validate(cbase, cmask))
return ret;
+ if (flags & ~SBI_PMU_START_FLAGS_MASK)
+ return SBI_ERR_INVALID_PARAM;
+
if (flags & SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT)
return SBI_ENO_SHMEM;
@@ -592,6 +595,8 @@ int sbi_pmu_ctr_start(unsigned long cbase, unsigned long cmask,
: 0x0;
ret = pmu_ctr_start_fw(phs, cidx, event_code, edata,
ival, bUpdate);
+ if (ret)
+ return ret;
} else {
if (cidx >= 3) {
struct sbi_pmu_hw_event_config *ev_cfg =
@@ -605,6 +610,8 @@ int sbi_pmu_ctr_start(unsigned long cbase, unsigned long cmask,
return ret;
}
ret = pmu_ctr_start_hw(cidx, ival, bUpdate);
+ if (ret)
+ return ret;
}
}
@@ -693,6 +700,9 @@ int sbi_pmu_ctr_stop(unsigned long cbase, unsigned long cmask,
if (!pmu_ctr_idx_validate(cbase, cmask))
return ret;
+ if (flag & ~SBI_PMU_STOP_FLAGS_MASK)
+ return SBI_ERR_INVALID_PARAM;
+
if (flag & SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT)
return SBI_ENO_SHMEM;
@@ -708,6 +718,9 @@ int sbi_pmu_ctr_stop(unsigned long cbase, unsigned long cmask,
else
ret = pmu_ctr_stop_hw(cidx);
+ if(ret)
+ return ret;
+
if (cidx > (CSR_INSTRET - CSR_CYCLE) && flag & SBI_PMU_STOP_FLAG_RESET) {
phs->active_events[cidx] = SBI_PMU_EVENT_IDX_INVALID;
pmu_reset_hw_mhpmevent(cidx);
@@ -1105,30 +1118,36 @@ int sbi_pmu_event_get_info(unsigned long shmem_phys_lo, unsigned long shmem_phys
if (event_type < 0) {
einfo[i].output = 0;
} else {
- for (j = 0; j < num_hw_events; j++) {
- temp = &hw_event_map[j];
- /* For raw events, event data is used as the select value */
- if (event_idx == SBI_PMU_EVENT_RAW_IDX ||
- event_idx == SBI_PMU_EVENT_RAW_V2_IDX) {
- /*
- * Only a raw event map entry carries a
- * meaningful select/select_mask pair, so
- * skip any entry which does not cover the
- * raw event index.
- */
- if (temp->start_idx > event_idx ||
- event_idx > temp->end_idx)
- continue;
- /* just match the selector */
- if (temp->select == (einfo[i].event_data &
- temp->select_mask)) {
+ if (event_type == SBI_PMU_EVENT_TYPE_FW) {
+ /* pmu_event_validate() already confirmed this event is valid; counter support is checked later by cfg_match/find_fw. */
+ einfo[i].output = 1;
+ continue;
+ } else {
+ for (j = 0; j < num_hw_events; j++) {
+ temp = &hw_event_map[j];
+ /* For raw events, event data is used as the select value */
+ if (event_idx == SBI_PMU_EVENT_RAW_IDX ||
+ event_idx == SBI_PMU_EVENT_RAW_V2_IDX) {
+ /*
+ * Only a raw event map entry carries a
+ * meaningful select/select_mask pair, so
+ * skip any entry which does not cover the
+ * raw event index.
+ */
+ if (temp->start_idx > event_idx ||
+ event_idx > temp->end_idx)
+ continue;
+ /* just match the selector */
+ if (temp->select == (einfo[i].event_data &
+ temp->select_mask)) {
+ found = true;
+ break;
+ }
+ } else if (temp->start_idx <= event_idx &&
+ event_idx <= temp->end_idx) {
found = true;
break;
}
- } else if (temp->start_idx <= event_idx &&
- event_idx <= temp->end_idx) {
- found = true;
- break;
}
}
if (found)
--
2.43.0
--
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^ permalink raw reply related [flat|nested] 5+ messages in thread