Re: [PATCH, RFC] Create 'slot' sysfs attribute in/sys/devices/system/cpu/cpuN/topology/

[Alex Chiang <achiang@hp.com>]

Hi Tony,

* Luck, Tony <tony.luck@intel.com>:
> > include/asm-x86/cpu.h         |    1 +
> 
> I assume this slipped in accidentally (though it would
> eventually be needed for an x86 version of this patch).

Well, it wasn't an accident, but I think I did screw up my
attempt at making this patch a nop on x86. The patch below should
have a better attempt at that.

> > +#ifdef	topology_slot
> > +define_id_show_func(slot);
> > +define_one_ro(slot);
> > +#define ref_slot_attr			&attr_slot.attr,
> > +#else
> > +#define ref_slot_attr
> > +#endif
> 
> This is a bit ugly ... I don't see how to make it better (but
> I'm sure that akpm will say "You could just ...", and then
> I'll wonder why I didn't think of that).

Hrm, I was just following a precedent here. I guess I'll wait for
enlightenment from akpm too. ;)

> > +EXPORT_SYMBOL(arch_set_topology_slot);
> 
> As the author you get to choose the license ... but there is
> strong movement to make new exported symbols GPL only.

Changed.

> When I apply this patch and run it on my tiger, I see a slew
> of
> 
> 	ACPI: Invalid PBLK length [0]
> 
> messages on my console during boot and the see

I don't think this should be coming from my patch. However, I did
update so that we're checking for a _SUN method underneath the
CPU before blinding stabbing around and trying to call it.

> 	$ cat /sys/devices/system/cpu/cpu0/topology/slot
> 	-1
> 
> So I guess that the _SUN method isn't there on my machine.

If you don't have _SUN on your machine, this version of the patch
should prevent those annoying messages from appearing.

However, you'll still see the sysfs attribute with a value of -1.
Personally, I don't think this is so bad, since on my legacy HP
machines, I get a -1 when I cat the 'physical_package_id'
attribute...

I'll defer to your judgement on this though.

/ac

From: Alex Chiang <achiang@hp.com>
Subject: [PATCH] Create 'slot' sysfs attribute in /sys/devices/system/cpu/cpuN/topology/

/sys/devices/system/cpu/cpuN/topology/physical_package_id exists,
but may contain incorrect information, especially on older ia64
platforms that do not have modern firmware.

Create a 'slot' attribute and define an interface that may be
populated via alternate sources, without breaking existing
functionality.

Implement this interface on ia64 by invoking the _SUN method on a
per cpu basis.

Leave other archs alone for now.

v1 -> v2:
	- Check for _SUN object on CPU before blindly attempting
	  to call it

Signed-off-by: Alex Chiang <achiang@hp.com>
---
 arch/ia64/kernel/setup.c      |    1 +
 arch/ia64/kernel/topology.c   |    6 ++++++
 drivers/acpi/processor_core.c |   11 +++++++++++
 drivers/base/topology.c       |    9 +++++++++
 include/asm-ia64/cpu.h        |    1 +
 include/asm-ia64/processor.h  |    7 ++++++-
 include/asm-ia64/topology.h   |    3 +++
 include/asm-x86/topology.h    |    2 ++
 8 files changed, 39 insertions(+), 1 deletions(-)

diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c
index 4aa9eae..228d960 100644
--- a/arch/ia64/kernel/setup.c
+++ b/arch/ia64/kernel/setup.c
@@ -735,6 +735,7 @@ identify_cpu (struct cpuinfo_ia64 *c)
 	 */
 	c->threads_per_core = c->cores_per_socket = c->num_log = 1;
 	c->socket_id = -1;
+	c->slot = -1;
 
 	identify_siblings(c);
 
diff --git a/arch/ia64/kernel/topology.c b/arch/ia64/kernel/topology.c
index a2484fc..512de14 100644
--- a/arch/ia64/kernel/topology.c
+++ b/arch/ia64/kernel/topology.c
@@ -27,6 +27,12 @@
 
 static struct ia64_cpu *sysfs_cpus;
 
+void ia64_set_topology_slot(int num, u32 slot)
+{
+	cpu_data(num)->slot = slot;
+}
+EXPORT_SYMBOL_GPL(ia64_set_topology_slot);
+
 int arch_register_cpu(int num)
 {
 #if defined (CONFIG_ACPI) && defined (CONFIG_HOTPLUG_CPU)
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 36a68fa..49fb2a0 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -509,6 +509,7 @@ static int get_cpu_id(acpi_handle handle, u32 acpi_id)
 static int acpi_processor_get_info(struct acpi_processor *pr, unsigned has_uid)
 {
 	acpi_status status = 0;
+	acpi_handle handle;
 	union acpi_object object = { 0 };
 	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
 	int cpu_index;
@@ -590,6 +591,16 @@ static int acpi_processor_get_info(struct acpi_processor *pr, unsigned has_uid)
 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d:%d]\n", pr->id,
 			  pr->acpi_id));
 
+	if (ACPI_SUCCESS(acpi_get_handle(pr->handle, "_SUN", &handle))) {
+		status = acpi_evaluate_object(pr->handle,
+						"_SUN", NULL, &buffer);
+		if (ACPI_FAILURE(status))
+			object.integer.value = -1;
+	} else {
+		object.integer.value = -1;
+	}
+	arch_set_topology_slot(pr->id, object.integer.value);
+
 	if (!object.processor.pblk_address)
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No PBLK (NULL address)\n"));
 	else if (object.processor.pblk_length != 6)
diff --git a/drivers/base/topology.c b/drivers/base/topology.c
index e1d3ad4..4fcffca 100644
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -57,6 +57,14 @@ define_one_ro(physical_package_id);
 #define ref_physical_package_id_attr
 #endif
 
+#ifdef	topology_slot
+define_id_show_func(slot);
+define_one_ro(slot);
+#define ref_slot_attr			&attr_slot.attr,
+#else
+#define ref_slot_attr
+#endif
+
 #ifdef topology_core_id
 define_id_show_func(core_id);
 define_one_ro(core_id);
@@ -83,6 +91,7 @@ define_one_ro(core_siblings);
 
 static struct attribute *default_attrs[] = {
 	ref_physical_package_id_attr
+	ref_slot_attr
 	ref_core_id_attr
 	ref_thread_siblings_attr
 	ref_core_siblings_attr
diff --git a/include/asm-ia64/cpu.h b/include/asm-ia64/cpu.h
index e87fa32..393e545 100644
--- a/include/asm-ia64/cpu.h
+++ b/include/asm-ia64/cpu.h
@@ -14,6 +14,7 @@ DECLARE_PER_CPU(struct ia64_cpu, cpu_devices);
 
 DECLARE_PER_CPU(int, cpu_state);
 
+extern void arch_set_topology_slot(int num, u32 slot);
 extern int arch_register_cpu(int num);
 #ifdef CONFIG_HOTPLUG_CPU
 extern void arch_unregister_cpu(int);
diff --git a/include/asm-ia64/processor.h b/include/asm-ia64/processor.h
index 741f7ec..066553c 100644
--- a/include/asm-ia64/processor.h
+++ b/include/asm-ia64/processor.h
@@ -125,6 +125,10 @@ struct ia64_psr {
  */
 struct cpuinfo_ia64 {
 	__u32 softirq_pending;
+
+#ifdef CONFIG_SMP
+	int cpu;
+#endif
 	__u64 itm_delta;	/* # of clock cycles between clock ticks */
 	__u64 itm_next;		/* interval timer mask value to use for next clock tick */
 	__u64 nsec_per_cyc;	/* (1000000000<<IA64_NSEC_PER_CYC_SHIFT)/itc_freq */
@@ -140,7 +144,6 @@ struct cpuinfo_ia64 {
 
 #ifdef CONFIG_SMP
 	__u64 loops_per_jiffy;
-	int cpu;
 	__u32 socket_id;	/* physical processor socket id */
 	__u16 core_id;		/* core id */
 	__u16 thread_id;	/* thread id */
@@ -150,6 +153,8 @@ struct cpuinfo_ia64 {
 	__u8  threads_per_core;	/* Threads per core */
 #endif
 
+	__u32 slot;		/* physical slot; can differ from socket_id */
+
 	/* CPUID-derived information: */
 	__u64 ppn;
 	__u64 features;
diff --git a/include/asm-ia64/topology.h b/include/asm-ia64/topology.h
index 2d67b72..f986693 100644
--- a/include/asm-ia64/topology.h
+++ b/include/asm-ia64/topology.h
@@ -110,12 +110,15 @@ void build_cpu_to_node_map(void);
 
 #ifdef CONFIG_SMP
 #define topology_physical_package_id(cpu)	(cpu_data(cpu)->socket_id)
+#define topology_slot(cpu)			(cpu_data(cpu)->slot)
 #define topology_core_id(cpu)			(cpu_data(cpu)->core_id)
 #define topology_core_siblings(cpu)		(cpu_core_map[cpu])
 #define topology_thread_siblings(cpu)		(per_cpu(cpu_sibling_map, cpu))
 #define smt_capable() 				(smp_num_siblings > 1)
 #endif
 
+#define arch_set_topology_slot(num, slot)	ia64_set_topology_slot(num,slot)
+
 #include <asm-generic/topology.h>
 
 #endif /* _ASM_IA64_TOPOLOGY_H */
diff --git a/include/asm-x86/topology.h b/include/asm-x86/topology.h
index 8af05a9..d4c922c 100644
--- a/include/asm-x86/topology.h
+++ b/include/asm-x86/topology.h
@@ -180,6 +180,8 @@ extern cpumask_t cpu_coregroup_map(int cpu);
 #define topology_thread_siblings(cpu)		(per_cpu(cpu_sibling_map, cpu))
 #endif
 
+#define arch_set_topology_slot(num, slot)
+
 #ifdef CONFIG_SMP
 #define mc_capable()			(boot_cpu_data.x86_max_cores > 1)
 #define smt_capable()			(smp_num_siblings > 1)
-- 
1.5.3.1.g1e61