[PATCH] lib: sbi: use unsigned masks for HPM counter 31

[Anup Patel]

On Fri, Aug 28, 2026 at 7:54 PM Pengpeng Hou <pengpeng at iscas.ac.cn> wrote:
>
> The HPM feature detector and CSR emulator build mhpm_mask bits with a
> plain signed 1. Both macro families expand through counter 31, so the
> last expansion evaluates 1 << 31 and shifts a signed int into its sign
> bit.
>
> Use BIT() at both sites. The mask is unsigned and bit 31 is part of the
> represented HPM counter set.
>
> Fixes: c744ed77b18c ("lib: sbi_pmu: Enable noncontigous hpm event and counters")
> Fixes: ee1f83ca848d ("lib: sbi_pmu: remove mhpm_count field in hart feature")
> Signed-off-by: Pengpeng Hou <pengpeng at iscas.ac.cn>

LGTM.

Reviewed-by: Anup Patel <anup at brainfault.org>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup

> ---
>  lib/sbi/sbi_emulate_csr.c | 2 +-
>  lib/sbi/sbi_hart.c        | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/sbi/sbi_emulate_csr.c b/lib/sbi/sbi_emulate_csr.c
> index c2253c82..5d3a6e9d 100644
> --- a/lib/sbi/sbi_emulate_csr.c
> +++ b/lib/sbi/sbi_emulate_csr.c
> @@ -103,7 +103,7 @@ int sbi_emulate_csr_read(int csr_num, struct sbi_trap_regs *regs,
>
>  #define switchcase_hpm(__uref, __mref, __csr)                          \
>         case __csr:                                                     \
> -               if (sbi_hart_mhpm_mask(scratch) & (1 << (__csr - __uref)))\
> +               if (sbi_hart_mhpm_mask(scratch) & BIT(__csr - __uref))  \
>                         return SBI_ENOTSUPP;                            \
>                 if (!hpm_allowed(__csr - __uref, prev_mode, virt))      \
>                         return SBI_ENOTSUPP;                            \
> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> index bee88557..8e4c36d0 100644
> --- a/lib/sbi/sbi_hart.c
> +++ b/lib/sbi/sbi_hart.c
> @@ -512,7 +512,7 @@ static int hart_detect_features(struct sbi_scratch *scratch, bool cold_boot)
>         if (!trap.cause) {                                                \
>                 csr_write_allowed(__csr, &trap, 1UL);                     \
>                 if (!trap.cause && csr_swap(__csr, oldval) == 1UL) {      \
> -                       (hfeatures->__mask) |= 1 << (__csr - CSR_MCYCLE); \
> +                       (hfeatures->__mask) |= BIT(__csr - CSR_MCYCLE);   \
>                 }                                                         \
>         }
>
>
> base-commit: 4e79fd7de59f1b2899092c1a84ce68c8ebc68f93
> --
> 2.43.0
>
>
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