lkml.org 
[lkml]   [2023]   [Aug]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH V3 1/4] arm_pmu: acpi: Refactor arm_spe_acpi_register_device()
    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

    \
     
     \ /
      Last update: 2023-08-08 18:30    [W:3.006 / U:0.360 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site