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Message-Id: <200811021942.48041.bjorn.helgaas@hp.com>
Date: Sun, 2 Nov 2008 19:42:47 -0700
From: Bjorn Helgaas <bjorn.helgaas@...com>
To: Zhao Yakui <yakui.zhao@...el.com>
Cc: Myron Stowe <myron.stowe@...com>,
"lenb@...nel.org" <lenb@...nel.org>,
"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Alexey Starikovskiy <aystarik@...il.com>
Subject: Re: [PATCH v2 2/3] ACPI: Behave uniquely based on processor declaration definition type
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@...com>
> > > > Cc: Alexey Starikovskiy <aystarik@...il.com>
> > > > Cc: Zhao Yakui <yakui.zhao@...el.com>
> > > > ---
> > > >
> > > > 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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