lib: sbi: Map only the counters enabled in hardware

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@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
index 5b845f8..376afec 100644 (file)
--- 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++;