Messages in this thread Patch in this message | | | Date | Wed, 16 Aug 2023 12:00:36 +0530 | Subject | Re: [PATCH V4 1/4] arm_pmu: acpi: Refactor arm_spe_acpi_register_device() | From | Anshuman Khandual <> |
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On 8/11/23 16:30, Will Deacon wrote: > On Fri, Aug 11, 2023 at 03:55:43PM +0530, Anshuman Khandual wrote: >> >> >> On 8/11/23 15:42, Will Deacon wrote: >>> 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? >> >> Otherwise '0' gsi on all cpus would just clear the above homogeneity >> test, and end up in acpi_register_gsi() making it fail, but with the >> following warning before returning with -ENXIO. >> >> irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH); >> if (irq < 0) { >> pr_warn("ACPI: %s Unable to register interrupt: %d\n", pdev->name, gsi); >> return -ENXIO; >> } > > Ah gotcha, thanks. > >> Is this behaviour better than returning 0 after detecting '0' gsi in >> the first cpu to avoid the above mentioned scenario ? Although 0 gsi >> followed by non-zero ones will still end up warning about a mismatch. > > Can we move the check _after_ the loop, then? That way, we still detect > mismatches but we'll quietly return 0 if nobody has an interrupt.
Sure, will fold in the following changes instead.
diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c index 845683ca7c64..d7beb035345a 100644 --- a/drivers/perf/arm_pmu_acpi.c +++ b/drivers/perf/arm_pmu_acpi.c @@ -98,9 +98,6 @@ 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) { hetid = this_hetid; @@ -111,6 +108,15 @@ arm_acpi_register_pmu_device(struct platform_device *pdev, u8 len, } } + /* + * This is a special case where no cpu on + * the system has the interrupt and which + * could not have been detected via above + * homogeneous mismatch test. + */ + if (!this_gsi) + return 0; + irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH); if (irq < 0) { pr_warn("ACPI: %s Unable to register interrupt: %d\n", pdev->name, gsi);
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