On Thu, Sep 14, 2023 at 05:13:41PM +0100, Jonathan Cameron wrote:
> On Wed, 13 Sep 2023 16:38:20 +0000
> James Morse <james.morse@xxxxxxx> wrote:
> > +static int acpi_processor_make_enabled(struct acpi_processor *pr)
> > +{
> > + unsigned long long sta;
> > + acpi_status status;
> > + bool present, enabled;
> > +
> > + if (!acpi_has_method(pr->handle, "_STA"))
> > + return arch_register_cpu(pr->id);
> > +
> > + status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
> > + if (ACPI_FAILURE(status))
> > + return -ENODEV;
> > +
> > + present = sta & ACPI_STA_DEVICE_PRESENT;
> > + enabled = sta & ACPI_STA_DEVICE_ENABLED;
> > +
> > + if (cpu_online(pr->id) && (!present || !enabled)) {
> > + pr_err_once(FW_BUG "CPU %u is online, but described as not present or disabled!\n", pr->id);
>
> Why once? If this for some reason happened on multiple CPUs I think we'd want to know.
>
> > + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
> > + } else if (!present || !enabled) {
> > + return -ENODEV;
> > + }
>
> I guess you didn't do a nested if here to avoid even longer lines.
> Could flip things around though I don't like this much either as it makes
> the normal good path exit mid way down.
>
> if (present && enabled)
> return arch_register_cpu(pr->id);
>
> if (!cpu_online(pr->id))
> return -ENODEV;
>
> pr_err...
> add_taint(...
>
> return arch_register_cpu(pr->id);
>
> Ah well. Some code just has to be less than pretty.
How about:
static int acpi_processor_should_register_cpu(struct acpi_processor *pr)
{
unsigned long long sta;
acpi_status status;
if (!acpi_has_method(pr->handle, "_STA"))
return 0;
status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
if (ACPI_FAILURE(status))
return -ENODEV;
if (sta & ACPI_STA_DEVICE_PRESENT && sta & ACPI_STA_DEVICE_ENABLED)
return 0;
if (cpu_online(pr->id)) {
pr_err_once(FW_BUG
"CPU %u is online, but described as not present or disabled!\n",
pr->id);
/* Register the CPU anyway */
return 0;
}
return -ENODEV;
}
static int acpi_processor_make_enabled(struct acpi_processor *pr)
{
int ret = acpi_processor_should_register_cpu(pr);
if (ret)
return ret;
return arch_register_cpu(pr->id);
}
I would keep the "cpu online but !present and !disabled" as a sub-block
because it makes better reading flow, but instead break the message as
I've indicated above.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
