On Mon, Apr 15, 2024 at 6:16 PM Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote: > > On Mon, Apr 15, 2024 at 5:49 PM Jonathan Cameron > <Jonathan.Cameron@xxxxxxxxxx> wrote: > > > > On Fri, 12 Apr 2024 20:10:54 +0200 > > "Rafael J. Wysocki" <rafael@xxxxxxxxxx> wrote: > > > > > On Fri, Apr 12, 2024 at 4:38 PM Jonathan Cameron > > > <Jonathan.Cameron@xxxxxxxxxx> wrote: > > > > > > > > The arm64 specific arch_register_cpu() needs to access the _STA > > > > method of the DSDT object so make it available by assigning the > > > > appropriate handle to the struct cpu instance. > > > > > > > > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > > > > --- > > > > drivers/acpi/acpi_processor.c | 3 +++ > > > > 1 file changed, 3 insertions(+) > > > > > > > > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c > > > > index 7a0dd35d62c9..93e029403d05 100644 > > > > --- a/drivers/acpi/acpi_processor.c > > > > +++ b/drivers/acpi/acpi_processor.c > > > > @@ -235,6 +235,7 @@ static int acpi_processor_get_info(struct acpi_device *device) > > > > union acpi_object object = { 0 }; > > > > struct acpi_buffer buffer = { sizeof(union acpi_object), &object }; > > > > struct acpi_processor *pr = acpi_driver_data(device); > > > > + struct cpu *c; > > > > int device_declaration = 0; > > > > acpi_status status = AE_OK; > > > > static int cpu0_initialized; > > > > @@ -314,6 +315,8 @@ static int acpi_processor_get_info(struct acpi_device *device) > > > > cpufreq_add_device("acpi-cpufreq"); > > > > } > > > > > > > > + c = &per_cpu(cpu_devices, pr->id); > > > > + ACPI_COMPANION_SET(&c->dev, device); > > > > > > This is also set for per_cpu(cpu_sys_devices, pr->id) in > > > acpi_processor_add(), via acpi_bind_one(). > > > > Hi Rafael, > > > > cpu_sys_devices gets filled with a pointer to this same structure. > > The contents gets set in register_cpu() so at this point > > it doesn't point anywhere. As a side note register_cpu() > > memsets to zero the value I set it to in the code above which isn't > > great, particularly as I want to use this in post_eject for > > arm64. > > > > We could make a copy of the handle and put it back after > > the memset in register_cpu() but that is also ugly. > > It's the best I've come up with to make sure this is still set > > come remove time but is rather odd. > > > > > > Moreover, there is some pr->id validation in acpi_processor_add(), so > > > it seems premature to use it here this way. > > > > > > I think that ACPI_COMPANION_SET() should be called from here on > > > per_cpu(cpu_sys_devices, pr->id) after validating pr->id (so the > > > pr->id validation should all be done here) and then NULL can be passed > > > as acpi_dev to acpi_bind_one() in acpi_processor_add(). Then, there > > > will be one physical device corresponding to the processor ACPI device > > > and no confusion. > > > > I'm fairly sure this is pointing to the same device but agreed this > > is a tiny bit confusing. However we can't use cpu_sys_devices at this point > > so I'm not immediately seeing a cleaner solution :( > > Well, OK. > > Please at least consider doing the pr->id validation checks before > setting the ACPI companion for &per_cpu(cpu_devices, pr->id). > > Also, acpi_bind_one() needs to be called on the "physical" devices > passed to ACPI_COMPANION_SET() (with NULL as the second argument) for > the reference counting and physical device lookup to work. > > Please also note that acpi_primary_dev_companion() should return > per_cpu(cpu_sys_devices, pr->id) for the processor ACPI device, which > depends on the order of acpi_bind_one() calls involving the same ACPI > device. Of course, if the value set by ACPI_COMPANION_SET() is cleared subsequently, the above is not needed, but then using ACPI_COMPANION_SET() is questionable overall.