Re: [PATCH v2 2/3] ACPI: Behave uniquely based on processor declaration definition type

[Bjorn Helgaas]

On Sunday 02 November 2008 6:15:17 pm Zhao Yakui wrote:
> On Mon, 2008-11-03 at 08:10 +0800, Myron Stowe wrote:
> > On Fri, 2008-10-31 at 09:19 +0800, Zhao Yakui wrote:
> > > On Fri, 2008-10-31 at 06:13 +0800, Myron Stowe wrote:
> > > > Associating a Local SAPIC with a processor object is dependent upon
> > > > the processor object's definition type.  CPUs declared as "Processor"
> > > > should use the Local SAPIC's 'processor_id', and CPUs declared as
> > > > "Device" should use the 'uid'.  Note that for "Processor"
> > > > declarations, even if a '_UID' child object exists, it has no bearing
> > > > with respect to mapping Local SAPICs (see section 5.2.11.13 - Local
> > > > SAPIC Structure; "Advanced Configuration and Power Interface
> > > > Specification", Revision 3.0b).
> > > >
> > > > This patch changes the lsapic mapping logic to rely on the
> > > > distinction of how the processor object was declared - the mapping
> > > > can't just try both types of matches irregardless of declaration type
> > > > and rely on one failing as is currently being done.
> > > >
> > > > Signed-off-by: Myron Stowe <myron.stowe@xxxxxx>
> > > > Cc: Alexey Starikovskiy <aystarik@xxxxxxxxx>
> > > > Cc: Zhao Yakui <yakui.zhao@xxxxxxxxx>
> > > > ---
> > > >
> > > >  drivers/acpi/processor_core.c |   75
> > > > +++++++++++++++++++++++------------------ 1 files changed, 42
> > > > insertions(+), 33 deletions(-)
> > > >
> > > > diff --git a/drivers/acpi/processor_core.c
> > > > b/drivers/acpi/processor_core.c index 0c670dd..35d33e8 100644
> > > > --- a/drivers/acpi/processor_core.c
> > > > +++ b/drivers/acpi/processor_core.c
> > > > @@ -410,7 +410,7 @@ static int acpi_processor_remove_fs(struct
> > > > acpi_device *device) /* Use the acpiid in MADT to map cpus in case of
> > > > SMP */
> > > >
> > > >  #ifndef CONFIG_SMP
> > > > -static int get_cpu_id(acpi_handle handle, u32 acpi_id) {return -1;}
> > > > +static int get_cpu_id(acpi_handle handle, int type, u32 acpi_id) {
> > > > return -1; } #else
> > > >
> > > >  static struct acpi_table_madt *madt;
> > > > @@ -429,27 +429,35 @@ static int map_lapic_id(struct
> > > > acpi_subtable_header *entry, }
> > > >
> > > >  static int map_lsapic_id(struct acpi_subtable_header *entry,
> > > > -		  u32 acpi_id, int *apic_id)
> > > > +		int device_declaration, u32 acpi_id, int *apic_id)
> > > >  {
> > > >  	struct acpi_madt_local_sapic *lsapic =
> > > >  		(struct acpi_madt_local_sapic *)entry;
> > > > +	u32 tmp = (lsapic->id << 8) | lsapic->eid;
> > > > +
> > > >  	/* Only check enabled APICs*/
> > > > -	if (lsapic->lapic_flags & ACPI_MADT_ENABLED) {
> > > > -		/* First check against id */
> > > > -		if (lsapic->processor_id == acpi_id) {
> > > > -			*apic_id = (lsapic->id << 8) | lsapic->eid;
> > > > -			return 1;
> > > > -		/* Check against optional uid */
> > > > -		} else if (entry->length >= 16 &&
> > > > -			lsapic->uid == acpi_id) {
> > > > -			*apic_id = lsapic->uid;
> > > > -			return 1;
> > > > -		}
> > > > -	}
> > > > +	if (!(lsapic->lapic_flags & ACPI_MADT_ENABLED))
> > > > +		return 0;
> > > > +
> > > > +	/* Device statement declaration type */
> > > > +	if (device_declaration) {
> > > > +		if (entry->length < 16)
> > > > +			printk(KERN_ERR PREFIX
> > > > +			    "Invalid LSAPIC with Device type processor (SAPIC ID %#x)\n",
> > > > +			    tmp);
> > > > +		else if (lsapic->uid == acpi_id)
> > > > +			goto found;
> > > > +	/* Processor statement declaration type */
> > > > +	} else if (lsapic->processor_id == acpi_id)
> > > > +		goto found;
> > > > +
> > > >  	return 0;
> > > > +found:
> > > > +	*apic_id = tmp;
> > > > +	return 1;
> > > >  }
> > > >
> > > > -static int map_madt_entry(u32 acpi_id)
> > > > +static int map_madt_entry(int type, u32 acpi_id)
> > > >  {
> > > >  	unsigned long madt_end, entry;
> > > >  	int apic_id = -1;
> > > > @@ -470,7 +478,7 @@ static int map_madt_entry(u32 acpi_id)
> > > >  			if (map_lapic_id(header, acpi_id, &apic_id))
> > > >  				break;
> > > >  		} else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
> > > > -			if (map_lsapic_id(header, acpi_id, &apic_id))
> > > > +			if (map_lsapic_id(header, type, acpi_id, &apic_id))
> > > >  				break;
> > > >  		}
> > > >  		entry += header->length;
> > > > @@ -478,7 +486,7 @@ static int map_madt_entry(u32 acpi_id)
> > > >  	return apic_id;
> > > >  }
> > > >
> > > > -static int map_mat_entry(acpi_handle handle, u32 acpi_id)
> > > > +static int map_mat_entry(acpi_handle handle, int type, u32 acpi_id)
> > > >  {
> > > >  	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> > > >  	union acpi_object *obj;
> > > > @@ -501,7 +509,7 @@ static int map_mat_entry(acpi_handle handle, u32
> > > > acpi_id) if (header->type == ACPI_MADT_TYPE_LOCAL_APIC) {
> > > >  		map_lapic_id(header, acpi_id, &apic_id);
> > > >  	} else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
> > > > -		map_lsapic_id(header, acpi_id, &apic_id);
> > > > +		map_lsapic_id(header, type, acpi_id, &apic_id);
> > > >  	}
> > > >
> > > >  exit:
> > > > @@ -510,14 +518,14 @@ exit:
> > > >  	return apic_id;
> > > >  }
> > > >
> > > > -static int get_cpu_id(acpi_handle handle, u32 acpi_id)
> > > > +static int get_cpu_id(acpi_handle handle, int type, u32 acpi_id)
> > > >  {
> > > >  	int i;
> > > >  	int apic_id = -1;
> > > >
> > > > -	apic_id = map_mat_entry(handle, acpi_id);
> > > > +	apic_id = map_mat_entry(handle, type, acpi_id);
> > > >  	if (apic_id == -1)
> > > > -		apic_id = map_madt_entry(acpi_id);
> > > > +		apic_id = map_madt_entry(type, acpi_id);
> > > >  	if (apic_id == -1)
> > > >  		return apic_id;
> > > >
> > > > @@ -533,15 +541,16 @@ static int get_cpu_id(acpi_handle handle, u32
> > > > acpi_id) Driver Interface
> > > >    
> > > > ---------------------------------------------------------------------
> > > >----- */
> > > >
> > > > -static int acpi_processor_get_info(struct acpi_processor *pr,
> > > > unsigned has_uid) +static int acpi_processor_get_info(struct
> > > > acpi_device *device) {
> > > >  	acpi_status status = 0;
> > > >  	union acpi_object object = { 0 };
> > > >  	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
> > > > -	int cpu_index;
> > > > +	struct acpi_processor *pr;
> > > > +	int cpu_index, device_declaration = 0;
> > > >  	static int cpu0_initialized;
> > > >
> > > > -
> > > > +	pr = acpi_driver_data(device);
> > > >  	if (!pr)
> > > >  		return -EINVAL;
> > > >
> > > > @@ -562,8 +571,11 @@ static int acpi_processor_get_info(struct
> > > > acpi_processor *pr, unsigned has_uid) ACPI_DEBUG_PRINT((ACPI_DB_INFO,
> > > >  				  "No bus mastering arbitration control\n"));
> > > >
> > > > -	/* Check if it is a Device with HID and UID */
> > > > -	if (has_uid) {
> > > > +	if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_HID)) {
> > > > +		/*
> > > > +		 * Declared with "Device" statement; match _UID.
> > > > +		 * Note that we don't handle string _UIDs yet.
> > >
> > > Looks very good.
> > > Can you add the check whether the device.flags.unique_id exists before
> > > evaluating the _UID object?
> > > If not exist, it indicates that the processor definition is incorrect.
> >
> > The additional check would create a relationship with
> > 'device.flags.unique_id' which seems redundant and would introduce
> > unnecessary complexity going forward.  While such an additional check
> > would possibly short circuit the call to 'acpi_evaluate_integer()' -
> > when FW is in error and a _UID child object does not exist; a case that
> > is already caught - this code is not in a performance path and thus
> > seems to yield no benefit.
>
> In your patch the device.flags.unique_id is not used. Maybe on some
> systems the processor is defined by Device. But there is no _UID
> object.This is incorrect.
>    IMO in such case we should catch such error.

If defective firmware uses a Device declaration for a processor, but
does not supply a _UID method, Myron's patch will attempt to evaluate
_UID, the evaluation will fail because _UID doesn't exist, we'll print
a message, and return -ENODEV.

That's the same way other errors in acpi_processor_get_info() are
handled.  Are you proposing that this one (a Device declaration
without _UID) should be handled differently?  How would you
suggest that it be handled?

Bjorn

> > > > +		 */
> > > >  		unsigned long long value;
> > > >  		status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
> > > >  						NULL, &value);
> > > > @@ -571,13 +583,10 @@ static int acpi_processor_get_info(struct
> > > > acpi_processor *pr, unsigned has_uid) printk(KERN_ERR PREFIX
> > > > "Evaluating processor _UID\n");
> > > >  			return -ENODEV;
> > > >  		}
> > > > +		device_declaration = 1;
> > > >  		pr->acpi_id = value;
> > > >  	} else {
> > > > -		/*
> > > > -		* Evalute the processor object.  Note that it is common on SMP to
> > > > -		* have the first (boot) processor with a valid PBLK address while
> > > > -		* all others have a NULL address.
> > > > -		*/
> > > > +		/* Declared with "Processor" statement; match ProcessorID */
> > > >  		status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
> > > >  		if (ACPI_FAILURE(status)) {
> > > >  			printk(KERN_ERR PREFIX "Evaluating processor object\n");
> > > > @@ -590,7 +599,7 @@ static int acpi_processor_get_info(struct
> > > > acpi_processor *pr, unsigned has_uid) */
> > > >  		pr->acpi_id = object.processor.proc_id;
> > > >  	}
> > > > -	cpu_index = get_cpu_id(pr->handle, pr->acpi_id);
> > > > +	cpu_index = get_cpu_id(pr->handle, device_declaration,
> > > > pr->acpi_id);
> > > >
> > > >  	/* Handle UP system running SMP kernel, with no LAPIC in MADT */
> > > >  	if (!cpu0_initialized && (cpu_index == -1) &&
> > > > @@ -662,7 +671,7 @@ static int __cpuinit acpi_processor_start(struct
> > > > acpi_device *device)
> > > >
> > > >  	pr = acpi_driver_data(device);
> > > >
> > > > -	result = acpi_processor_get_info(pr, device->flags.unique_id);
> > > > +	result = acpi_processor_get_info(device);
> > > >  	if (result) {
> > > >  		/* Processor is physically not present */
> > > >  		return 0;
>
> --
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