Messages in this thread | | | Date | Tue, 8 Aug 2023 14:21:57 +0100 | From | Will Deacon <> | Subject | Re: [PATCH V3 1/4] arm_pmu: acpi: Refactor arm_spe_acpi_register_device() |
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On Mon, Aug 07, 2023 at 11:03:40AM +0530, Anshuman Khandual wrote: > On 8/4/23 22:09, Will Deacon wrote: > > On Thu, Aug 03, 2023 at 11:43:27AM +0530, Anshuman Khandual wrote: > >> On 8/3/23 11:26, 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; > >> > >> Moved parse_gsi() return code checking to its original place just to > >> make it similar in semantics to existing 'gicc->header.length check'. > >> If 'gsi' is valid i.e atleast a single cpu has been probed, return > >> -ENXIO indicating mismatch, otherwise just return 0. > > > > Wouldn't that still be the case without the check in this hunk? We'd run > > into the homogeneous check and return -ENXIO from there, no? > Although the return code will be the same i.e -ENXIO, but not for the same reason. > > this_gsi = parse_gsi(gicc); > if (!this_gsi) > return gsi ? -ENXIO : 0; > > This returns 0 when IRQ could not be parsed for the first cpu, but returns -ENXIO > for subsequent cpus. Although return code -ENXIO here still indicates IRQ parsing > to have failed. > > } else if (hetid != this_hetid || gsi != this_gsi) { > pr_warn("ACPI: %s: must be homogeneous\n", pdev->name); > return -ENXIO; > } > > This returns -ENXIO when there is a IRQ mismatch. But if the above check is not > there, -ENXIO return code here could not be classified into IRQ parse problem or > mismatch without looking into the IRQ value.
Sorry, but I don't understand your point here. If any of this fails, there's going to be some debugging needed to look at the ACPI tables; the only difference with my suggestion is that you'll get a message indicating that the devices aren't homogeneous, which I think is helpful.
Will
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