Re: [PATCH V4 1/4] arm_pmu: acpi: Refactor arm_spe_acpi_register_device()

Will Deacon
2023-08-11T10:12:42Z

On Fri, Aug 11, 2023 at 02:13:42PM +0530, Anshuman Khandual wrote:
> On 8/8/23 13:52, Anshuman Khandual wrote:
> > + /*
> > + * Sanity check all the GICC tables for the same interrupt
> > + * number. For now, only support homogeneous ACPI machines.
> > + */
> > + for_each_possible_cpu(cpu) {
> > + struct acpi_madt_generic_interrupt *gicc;
> > +
> > + gicc = acpi_cpu_get_madt_gicc(cpu);
> > + if (gicc->header.length < len)
> > + return gsi ? -ENXIO : 0;
> > +
> > + this_gsi = parse_gsi(gicc);
> > + if (!this_gsi)
> > + return gsi ? -ENXIO : 0;
> > +
> > + this_hetid = find_acpi_cpu_topology_hetero_id(cpu);
> > + if (!gsi) {
> > + hetid = this_hetid;
> > + gsi = this_gsi;
> > + } else if (hetid != this_hetid || gsi != this_gsi) {
> > + pr_warn("ACPI: %s: must be homogeneous\n", pdev->name);
> > + return -ENXIO;
> > + }
> > + }
>
> As discussed on the previous version i.e V3 thread, will move the
> 'this_gsi' check after parse_gsi(), inside if (!gsi) conditional
> block. This will treat subsequent cpu parse_gsi()'s failure as a
> mismatch thus triggering the pr_warn() message.
>
> diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
> index 845683ca7c64..6eae772d6298 100644
> --- a/drivers/perf/arm_pmu_acpi.c
> +++ b/drivers/perf/arm_pmu_acpi.c
> @@ -98,11 +98,11 @@ arm_acpi_register_pmu_device(struct platform_device *pdev, u8 len,
> return gsi ? -ENXIO : 0;
>
> this_gsi = parse_gsi(gicc);
> - if (!this_gsi)
> - return gsi ? -ENXIO : 0;
> -
> this_hetid = find_acpi_cpu_topology_hetero_id(cpu);
> if (!gsi) {
> + if (!this_gsi)
> + return 0;

Why do you need this hunk?

Will