Re: [PATCH v9 17/20] RISC-V: perf: Add legacy event encodings via sysfs

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The macro RVPMU_EVENT_ATTR_RESOLVE performs single-level stringification, preventing macro expansion of event configuration values.
--

--- Patch [17]: [PATCH v9 17/20] RISC-V: perf: Add legacy event encodings via sysfs ---
commit b1ff3421691bcc5997cb4d931f9fdffb9eef0d1c
Author: Atish Patra <[email protected]>

RISC-V: perf: Add legacy event encodings via sysfs

This commit defines sysfs entries for legacy events to expose event
encoding and counter maps to tools like perf.

> diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
> index ee0c077859273..5eb49db8bc7c1 100644
> --- a/drivers/perf/riscv_pmu_sbi.c
> +++ b/drivers/perf/riscv_pmu_sbi.c
> @@ -130,7 +130,20 @@ static struct attribute_group riscv_cdeleg_pmu_format_group = {
>  	.attrs = riscv_cdeleg_pmu_formats_attr,
>  };
>  
> +#define RVPMU_EVENT_ATTR_RESOLVE(m) #m

[Severity: Medium]
Does this single-level stringification handle macro arguments correctly?

If a platform driver defines event mappings and passes standard kernel macros
for the config or mask arguments to RVPMU_EVENT_CMASK_ATTR, this definition
will stringify them verbatim without evaluation.

For example, passing a macro like RISCV_PMU_CYCLE_FIXED_CTR_MASK would emit
the literal string "event=RISCV_PMU_CYCLE_FIXED_CTR_MASK" instead of its
numeric value. This breaks the perf tool's ability to parse the event
encoding, rendering the PMU events unusable.

Would it be better to use __stringify() from linux/stringify.h so that both
literal numbers and macros evaluate correctly?

> +#define RVPMU_EVENT_CMASK_ATTR(_name, _var, config, mask) \
> +	PMU_EVENT_ATTR_STRING(_name, rvpmu_event_attr_##_var, \
> +			      "event=" RVPMU_EVENT_ATTR_RESOLVE(config) \
> +			      ",counterid_mask=" RVPMU_EVENT_ATTR_RESOLVE(mask))
> +

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=17