| Message ID | 20240412143719.11398-3-Jonathan.Cameron@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | ACPI/arm64: add support for virtual cpu hotplug | expand |
On Fri, Apr 12, 2024 at 4:38 PM Jonathan Cameron <Jonathan.Cameron@huawei.com> 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@huawei.com> > --- > 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(). 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. > /* > * Extra Processor objects may be enumerated on MP systems with > * less than the max # of CPUs. They should be ignored _iff > -- > 2.39.2 >
On Fri, 12 Apr 2024 20:10:54 +0200 "Rafael J. Wysocki" <rafael@kernel.org> wrote: > On Fri, Apr 12, 2024 at 4:38 PM Jonathan Cameron > <Jonathan.Cameron@huawei.com> 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@huawei.com> > > --- > > 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 :( Jonathan > > > /* > > * Extra Processor objects may be enumerated on MP systems with > > * less than the max # of CPUs. They should be ignored _iff > > -- > > 2.39.2 > >
On Mon, Apr 15, 2024 at 5:49 PM Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote: > > On Fri, 12 Apr 2024 20:10:54 +0200 > "Rafael J. Wysocki" <rafael@kernel.org> wrote: > > > On Fri, Apr 12, 2024 at 4:38 PM Jonathan Cameron > > <Jonathan.Cameron@huawei.com> 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@huawei.com> > > > --- > > > 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.
On Mon, Apr 15, 2024 at 6:16 PM Rafael J. Wysocki <rafael@kernel.org> wrote: > > On Mon, Apr 15, 2024 at 5:49 PM Jonathan Cameron > <Jonathan.Cameron@huawei.com> wrote: > > > > On Fri, 12 Apr 2024 20:10:54 +0200 > > "Rafael J. Wysocki" <rafael@kernel.org> wrote: > > > > > On Fri, Apr 12, 2024 at 4:38 PM Jonathan Cameron > > > <Jonathan.Cameron@huawei.com> 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@huawei.com> > > > > --- > > > > 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.
On Mon, 15 Apr 2024 18:19:17 +0200 "Rafael J. Wysocki" <rafael@kernel.org> wrote: > On Mon, Apr 15, 2024 at 6:16 PM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > On Mon, Apr 15, 2024 at 5:49 PM Jonathan Cameron > > <Jonathan.Cameron@huawei.com> wrote: > > > > > > On Fri, 12 Apr 2024 20:10:54 +0200 > > > "Rafael J. Wysocki" <rafael@kernel.org> wrote: > > > > > > > On Fri, Apr 12, 2024 at 4:38 PM Jonathan Cameron > > > > <Jonathan.Cameron@huawei.com> 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@huawei.com> > > > > > --- > > > > > 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. Agreed + smoothing over that by stashing and putting it back doesn't work because there is an additional call to acpi_bind_one() inbetween here and the one you reference. The arch_register_cpu() calls end up calling register_cpu() / device_register() / acpi_device_notify() / acpi_bind_one() With current code that fails (silently) If I make sure the handle is set before register_cpu() then it succeeds, but we end up with duplicate sysfs files etc because we bind twice. I think the only way around this is larger reorganization of the CPU hotplug code to pull the arch_register_cpu() call to where the acpi_bind_one() call is. However that changes a lot more than I'd like (and I don't have it working yet). Alternatively find somewhere else to stash the handle, or just add it as a parameter to arch_register_cpu(). Right now this feels the easier path to me. arch_register_cpu(int cpu, acpi_handle handle) Would that be a path you'd consider? Jonathan
On Mon, 15 Apr 2024 17:50:57 +0100 Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote: > On Mon, 15 Apr 2024 18:19:17 +0200 > "Rafael J. Wysocki" <rafael@kernel.org> wrote: > > > On Mon, Apr 15, 2024 at 6:16 PM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > > > On Mon, Apr 15, 2024 at 5:49 PM Jonathan Cameron > > > <Jonathan.Cameron@huawei.com> wrote: > > > > > > > > On Fri, 12 Apr 2024 20:10:54 +0200 > > > > "Rafael J. Wysocki" <rafael@kernel.org> wrote: > > > > > > > > > On Fri, Apr 12, 2024 at 4:38 PM Jonathan Cameron > > > > > <Jonathan.Cameron@huawei.com> 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@huawei.com> > > > > > > --- > > > > > > 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. > > Agreed + smoothing over that by stashing and putting it back doesn't > work because there is an additional call to acpi_bind_one() inbetween > here and the one you reference. > > The arch_register_cpu() calls end up calling register_cpu() / > device_register() / acpi_device_notify() / acpi_bind_one() > > With current code that fails (silently) > If I make sure the handle is set before register_cpu() then it > succeeds, but we end up with duplicate sysfs files etc because we > bind twice. > > I think the only way around this is larger reorganization of the > CPU hotplug code to pull the arch_register_cpu() call to where > the acpi_bind_one() call is. However that changes a lot more than I'd like > (and I don't have it working yet). > > Alternatively find somewhere else to stash the handle, or just add it as > a parameter to arch_register_cpu(). Right now this feels the easier > path to me. arch_register_cpu(int cpu, acpi_handle handle) > > Would that be a path you'd consider? Another option would be to do the per_cpu(processors, pr->id) = pr a few lines earlier than currently and access that directly from the arch_register_cpu() call. Similarly remove that reference a bit later and use it in arch_unregister_cpu(). This seems like the simplest solution, but I may be missing something. Jonathan > > Jonathan > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On Mon, Apr 15, 2024 at 7:35 PM Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote: > > On Mon, 15 Apr 2024 17:50:57 +0100 > Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote: > > > On Mon, 15 Apr 2024 18:19:17 +0200 > > "Rafael J. Wysocki" <rafael@kernel.org> wrote: > > > > > On Mon, Apr 15, 2024 at 6:16 PM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > > > > > On Mon, Apr 15, 2024 at 5:49 PM Jonathan Cameron > > > > <Jonathan.Cameron@huawei.com> wrote: > > > > > > > > > > On Fri, 12 Apr 2024 20:10:54 +0200 > > > > > "Rafael J. Wysocki" <rafael@kernel.org> wrote: > > > > > > > > > > > On Fri, Apr 12, 2024 at 4:38 PM Jonathan Cameron > > > > > > <Jonathan.Cameron@huawei.com> 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@huawei.com> > > > > > > > --- > > > > > > > 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. > > > > Agreed + smoothing over that by stashing and putting it back doesn't > > work because there is an additional call to acpi_bind_one() inbetween > > here and the one you reference. > > > > The arch_register_cpu() calls end up calling register_cpu() / > > device_register() / acpi_device_notify() / acpi_bind_one() > > > > With current code that fails (silently) And that's why there is an explicit acpi_bind_one() invocation in acpi_processor_add(). > > If I make sure the handle is set before register_cpu() then it > > succeeds, but we end up with duplicate sysfs files etc because we > > bind twice. Right, I should have recalled that earlier. > > I think the only way around this is larger reorganization of the > > CPU hotplug code to pull the arch_register_cpu() call to where > > the acpi_bind_one() call is. However that changes a lot more than I'd like > > (and I don't have it working yet). I see. > > Alternatively find somewhere else to stash the handle, or just add it as > > a parameter to arch_register_cpu(). Right now this feels the easier > > path to me. arch_register_cpu(int cpu, acpi_handle handle) > > > > Would that be a path you'd consider? > > Another option would be to do the per_cpu(processors, pr->id) = pr > a few lines earlier than currently and access that directly from the > arch_register_cpu() call. Similarly remove that reference a bit later and > use it in arch_unregister_cpu(). > > This seems like the simplest solution, but I may be missing something. This should work AFAICS, but I'd move the entire piece of code between BUG_ON() and setting per_cpu(processors, pr->id) inclusive: BUG_ON(pr->id >= nr_cpu_ids); /* * 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. */ goto err; } /* * processor_device_array is not cleared on errors to allow buggy BIOS * checks. */ per_cpu(processor_device_array, pr->id) = device; per_cpu(processors, pr->id) = pr; into acpi_processor_get_info(), right after the point where pr->id is set.
On Mon, 15 Apr 2024 19:41:43 +0200 "Rafael J. Wysocki" <rafael@kernel.org> wrote: > On Mon, Apr 15, 2024 at 7:35 PM Jonathan Cameron > <Jonathan.Cameron@huawei.com> wrote: > > > > On Mon, 15 Apr 2024 17:50:57 +0100 > > Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote: > > > > > On Mon, 15 Apr 2024 18:19:17 +0200 > > > "Rafael J. Wysocki" <rafael@kernel.org> wrote: > > > > > > > On Mon, Apr 15, 2024 at 6:16 PM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > > > > > > > On Mon, Apr 15, 2024 at 5:49 PM Jonathan Cameron > > > > > <Jonathan.Cameron@huawei.com> wrote: > > > > > > > > > > > > On Fri, 12 Apr 2024 20:10:54 +0200 > > > > > > "Rafael J. Wysocki" <rafael@kernel.org> wrote: > > > > > > > > > > > > > On Fri, Apr 12, 2024 at 4:38 PM Jonathan Cameron > > > > > > > <Jonathan.Cameron@huawei.com> 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@huawei.com> > > > > > > > > --- > > > > > > > > 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. > > > > > > Agreed + smoothing over that by stashing and putting it back doesn't > > > work because there is an additional call to acpi_bind_one() inbetween > > > here and the one you reference. > > > > > > The arch_register_cpu() calls end up calling register_cpu() / > > > device_register() / acpi_device_notify() / acpi_bind_one() > > > > > > With current code that fails (silently) > > And that's why there is an explicit acpi_bind_one() invocation in > acpi_processor_add(). > > > > If I make sure the handle is set before register_cpu() then it > > > succeeds, but we end up with duplicate sysfs files etc because we > > > bind twice. > > Right, I should have recalled that earlier. > > > > I think the only way around this is larger reorganization of the > > > CPU hotplug code to pull the arch_register_cpu() call to where > > > the acpi_bind_one() call is. However that changes a lot more than I'd like > > > (and I don't have it working yet). > > I see. > > > > Alternatively find somewhere else to stash the handle, or just add it as > > > a parameter to arch_register_cpu(). Right now this feels the easier > > > path to me. arch_register_cpu(int cpu, acpi_handle handle) > > > > > > Would that be a path you'd consider? > > > > Another option would be to do the per_cpu(processors, pr->id) = pr > > a few lines earlier than currently and access that directly from the > > arch_register_cpu() call. Similarly remove that reference a bit later and > > use it in arch_unregister_cpu(). > > > > This seems like the simplest solution, but I may be missing something. > > This should work AFAICS, but I'd move the entire piece of code between > BUG_ON() and setting per_cpu(processors, pr->id) inclusive: Hi Rafael, Unfortunately this is more complex on x86 than I realized :( On x86 the initial pr->id is invalid, which is one of the conditions that leads to acpi_processor_hotadd_init() being called. It only become valid after acpi_map_cpu() in acpi_processor_hotadd_init(). So the best I can immediately come up with is to factor out these checks and the setting of the per_cpu structures and set them either in acpi_processor_hotadd_init() or in an else for the non hotplug / normal registration path (where the pr->id is valid). Naturally found this on my final set of tests... A little ugly but not 'too bad'. Jonathan p.s. No one minds if I break x86, right? > > BUG_ON(pr->id >= nr_cpu_ids); > > /* > * 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. */ > goto err; > } > /* > * processor_device_array is not cleared on errors to allow buggy BIOS > * checks. > */ > per_cpu(processor_device_array, pr->id) = device; > per_cpu(processors, pr->id) = pr; > > into acpi_processor_get_info(), right after the point where pr->id is set.
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); /* * Extra Processor objects may be enumerated on MP systems with * less than the max # of CPUs. They should be ignored _iff
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@huawei.com> --- drivers/acpi/acpi_processor.c | 3 +++ 1 file changed, 3 insertions(+)