[PATCH v2 2/3] lib: sbi_pmu: Match raw event selector only against raw event map entries

["David E. Garcia Porras" <david.garcia@aheadcomputing.com>]

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


-- 
opensbi mailing list
opensbi@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/opensbi