From d97cfb33ae1ac0d9eebce1a03c96497a1f8f4c67 Mon Sep 17 00:00:00 2001 From: "David E. Garcia Porras" Date: Tue, 18 Aug 2026 15:00:21 -0600 Subject: [PATCH] lib: sbi_pmu: Return invalid param error for reserved event_idx bits 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 Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20260818210023.466462-2-david.garcia@aheadcomputing.com Signed-off-by: Anup Patel --- 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;