[PATCH v1 1/3] lib: sbi: Map only the counters enabled in hardware

[Atish Patra]

The counter mapping in DT may be incorrect if all the counters specified
in the mapping are actually not physically present in the hardware.
OpenSBI should only keep a mapping of counters enabled in hardware and
defined in DT. This assume that all the programmable hpmcounters are
consecutive as it doesn't make sense to build a system with sparse
hpmcounters.

Signed-off-by: Atish Patra <atishp at rivosinc.com>
---
 lib/sbi/sbi_pmu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
index 5b845f835e79..376afec13491 100644
--- a/lib/sbi/sbi_pmu.c
+++ b/lib/sbi/sbi_pmu.c
@@ -181,6 +181,9 @@ static int pmu_add_hw_event_map(u32 eidx_start, u32 eidx_end, u32 cmap,
 	int i = 0;
 	bool is_overlap;
 	struct sbi_pmu_hw_event *event = &hw_event_map[num_hw_events];
+	struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
+	int hw_ctr_avail = sbi_hart_mhpm_count(scratch);
+	uint32_t ctr_avail_mask = ((uint32_t)(~0) >> (32 - (hw_ctr_avail + 3)));
 
 	/* The first two counters are reserved by priv spec */
 	if (eidx_start > SBI_PMU_HW_INSTRUCTIONS && (cmap & SBI_PMU_FIXED_CTR_MASK))
@@ -208,7 +211,8 @@ static int pmu_add_hw_event_map(u32 eidx_start, u32 eidx_end, u32 cmap,
 	}
 
 	event->select_mask = select_mask;
-	event->counters = cmap;
+	/* Map the only the counters that are available in the hardware */
+	event->counters = cmap & ctr_avail_mask;
 	event->select = select;
 	num_hw_events++;
 
-- 
2.30.2