On Tue, Apr 30, 2024 at 12:45 PM Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> wrote: > > On Tue, 30 Apr 2024 12:17:38 +0200 > "Rafael J. Wysocki" <rafael@xxxxxxxxxx> wrote: > > > On Tue, Apr 30, 2024 at 12:13 PM Jonathan Cameron > > <Jonathan.Cameron@xxxxxxxxxx> wrote: > > > > > > On Tue, 30 Apr 2024 10:28:38 +0100 > > > Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> wrote: > > > > > > > On Tue, 30 Apr 2024 14:17:24 +1000 > > > > Gavin Shan <gshan@xxxxxxxxxx> wrote: > > > > > > > > > On 4/26/24 23:51, Jonathan Cameron wrote: > > > > > > Make the per_cpu(processors, cpu) entries available earlier so that > > > > > > they are available in arch_register_cpu() as ARM64 will need access > > > > > > to the acpi_handle to distinguish between acpi_processor_add() > > > > > > and earlier registration attempts (which will fail as _STA cannot > > > > > > be checked). > > > > > > > > > > > > Reorder the remove flow to clear this per_cpu() after > > > > > > arch_unregister_cpu() has completed, allowing it to be used in > > > > > > there as well. > > > > > > > > > > > > Note that on x86 for the CPU hotplug case, the pr->id prior to > > > > > > acpi_map_cpu() may be invalid. Thus the per_cpu() structures > > > > > > must be initialized after that call or after checking the ID > > > > > > is valid (not hotplug path). > > > > > > > > > > > > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > > > > > > > > > > > > --- > > > > > > v8: On buggy bios detection when setting per_cpu structures > > > > > > do not carry on. > > > > > > Fix up the clearing of per cpu structures to remove unwanted > > > > > > side effects and ensure an error code isn't use to reference them. > > > > > > --- > > > > > > drivers/acpi/acpi_processor.c | 79 +++++++++++++++++++++-------------- > > > > > > 1 file changed, 48 insertions(+), 31 deletions(-) > > > > > > > > > > > > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c > > > > > > index ba0a6f0ac841..3b180e21f325 100644 > > > > > > --- a/drivers/acpi/acpi_processor.c > > > > > > +++ b/drivers/acpi/acpi_processor.c > > > > > > @@ -183,8 +183,38 @@ static void __init acpi_pcc_cpufreq_init(void) {} > > > > > > #endif /* CONFIG_X86 */ > > > > > > > > > > > > /* Initialization */ > > > > > > +static DEFINE_PER_CPU(void *, processor_device_array); > > > > > > + > > > > > > +static bool acpi_processor_set_per_cpu(struct acpi_processor *pr, > > > > > > + struct acpi_device *device) > > > > > > +{ > > > > > > + BUG_ON(pr->id >= nr_cpu_ids); > > > > > > > > > > One blank line after BUG_ON() if we need to follow original implementation. > > > > > > > > Sure unintentional - I'll put that back. > > > > > > > > > > > > > > > + /* > > > > > > + * Buggy BIOS check. > > > > > > + * ACPI id of processors can be reported wrongly by the BIOS. > > > > > > + * Don't trust it blindly > > > > > > + */ > > > > > > + if (per_cpu(processor_device_array, pr->id) != NULL && > > > > > > + per_cpu(processor_device_array, pr->id) != device) { > > > > > > + dev_warn(&device->dev, > > > > > > + "BIOS reported wrong ACPI id %d for the processor\n", > > > > > > + pr->id); > > > > > > + /* Give up, but do not abort the namespace scan. */ > > > > > > > > > > It depends on how the return value is handled by the caller if the namespace > > > > > is continued to be scanned. The caller can be acpi_processor_hotadd_init() > > > > > and acpi_processor_get_info() after this patch is applied. So I think this > > > > > specific comment need to be moved to the caller. > > > > > > > > Good point. This gets messy and was an unintended change. > > > > > > > > Previously the options were: > > > > 1) acpi_processor_get_info() failed for other reasons - this code was never called. > > > > 2) acpi_processor_get_info() succeeded without acpi_processor_hotadd_init (non hotplug) > > > > this code then ran and would paper over the problem doing a bunch of cleanup under err. > > > > 3) acpi_processor_get_info() succeeded with acpi_processor_hotadd_init called. > > > > This code then ran and would paper over the problem doing a bunch of cleanup under err. > > > > > > > > We should maintain that or argue cleanly against it. > > > > > > > > This isn't helped the the fact I have no idea which cases we care about for that bios > > > > bug handling. Do any of those bios's ever do hotplug? Guess we have to try and maintain > > > > whatever protection this was offering. > > > > > > > > Also, the original code leaks data in some paths and I have limited idea > > > > of whether it is intentional or not. So to tidy the issue up that you've identified > > > > I'll need to try and make that code consistent first. > > > > > > > > I suspect the only way to do that is going to be to duplicate the allocations we > > > > 'want' to leak to deal with the bios bug detection. > > > > > > > > For example acpi_processor_get_info() failing leaks pr and pr->throttling.shared_cpu_map > > > > before this series. After this series we need pr to leak because it's used for the detection > > > > via processor_device_array. > > > > > > > > I'll work through this but it's going to be tricky to tell if we get right. > > > > Step 1 will be closing the existing leaks and then we will have something > > > > consistent to build on. > > > > > > > I 'think' that fixing the original leaks makes this all much more straight forward. > > > That return 0 for acpi_processor_get_info() never made sense as far as I can tell. > > > The pr isn't used after this point. > > > > > > What about something along lines of. > > > > > > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c > > > index 161c95c9d60a..97cff4492304 100644 > > > --- a/drivers/acpi/acpi_processor.c > > > +++ b/drivers/acpi/acpi_processor.c > > > @@ -392,8 +392,10 @@ static int acpi_processor_add(struct acpi_device *device, > > > device->driver_data = pr; > > > > > > result = acpi_processor_get_info(device); > > > - if (result) /* Processor is not physically present or unavailable */ > > > - return 0; > > > + if (result) { /* Processor is not physically present or unavailable */ > > > + result = 0; > > > > As per my previous message (just sent) this should be an error code, > > as returning 0 from acpi_processor_add() is generally problematic. > Ok. I'll switch to that, but as a separate precusor patch. Independent of > the memory leak fixes. Sure, thank you!