[PATCH for review] [133/145] x86_64: Support physical cpu hotplug for x86_64

Andi Kleen
2006-08-10T19:45:05Z

r

From: Ashok Raj <ashok.raj@intel.com>

This patch enables ACPI based physical CPU hotplug support for x86_64.
Implements acpi_map_lsapic() and acpi_unmap_lsapic() to support physical cpu
hotplug.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@muc.de>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

arch/i386/kernel/acpi/boot.c | 69 ++++++++++++++++++++++++++++++++++++++++---
arch/i386/kernel/mpparse.c | 2 -
include/asm-i386/smp.h | 1
3 files changed, 67 insertions(+), 5 deletions(-)

Index: linux/arch/i386/kernel/acpi/boot.c
===================================================================
--- linux.orig/arch/i386/kernel/acpi/boot.c
+++ linux/arch/i386/kernel/acpi/boot.c
@@ -26,6 +26,7 @@
#include <linux/init.h>
#include <linux/acpi.h>
#include <linux/efi.h>
+#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/dmi.h>
#include <linux/irq.h>
@@ -512,16 +513,76 @@ EXPORT_SYMBOL(acpi_register_gsi);
#ifdef CONFIG_ACPI_HOTPLUG_CPU
int acpi_map_lsapic(acpi_handle handle, int *pcpu)
{
- /* TBD */
- return -EINVAL;
+ struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ union acpi_object *obj;
+ struct acpi_table_lapic *lapic;
+ cpumask_t tmp_map, new_map;
+ u8 physid;
+ int cpu;
+
+ if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
+ return -EINVAL;
+
+ if (!buffer.length || !buffer.pointer)
+ return -EINVAL;
+
+ obj = buffer.pointer;
+ if (obj->type != ACPI_TYPE_BUFFER ||
+ obj->buffer.length < sizeof(*lapic)) {
+ kfree(buffer.pointer);
+ return -EINVAL;
+ }
+
+ lapic = (struct acpi_table_lapic *)obj->buffer.pointer;
+
+ if ((lapic->header.type != ACPI_MADT_LAPIC) ||
+ (!lapic->flags.enabled)) {
+ kfree(buffer.pointer);
+ return -EINVAL;
+ }
+
+ physid = lapic->id;
+
+ kfree(buffer.pointer);
+ buffer.length = ACPI_ALLOCATE_BUFFER;
+ buffer.pointer = NULL;
+
+ tmp_map = cpu_present_map;
+ mp_register_lapic(physid, lapic->flags.enabled);
+
+ /*
+ * If mp_register_lapic successfully generates a new logical cpu
+ * number, then the following will get us exactly what was mapped
+ */
+ cpus_andnot(new_map, cpu_present_map, tmp_map);
+ if (cpus_empty(new_map)) {
+ printk ("Unable to map lapic to logical cpu number\n");
+ return -EINVAL;
+ }
+
+ cpu = first_cpu(new_map);
+
+ *pcpu = cpu;
+ return 0;
}

EXPORT_SYMBOL(acpi_map_lsapic);

int acpi_unmap_lsapic(int cpu)
{
- /* TBD */
- return -EINVAL;
+ int i;
+
+ for_each_possible_cpu(i) {
+ if (x86_acpiid_to_apicid[i] == x86_cpu_to_apicid[cpu]) {
+ x86_acpiid_to_apicid[i] = -1;
+ break;
+ }
+ }
+ x86_cpu_to_apicid[cpu] = -1;
+ cpu_clear(cpu, cpu_present_map);
+ num_processors--;
+
+ return (0);
}

EXPORT_SYMBOL(acpi_unmap_lsapic);
Index: linux/arch/i386/kernel/mpparse.c
===================================================================
--- linux.orig/arch/i386/kernel/mpparse.c
+++ linux/arch/i386/kernel/mpparse.c
@@ -69,7 +69,7 @@ unsigned int def_to_bigsmp = 0;
/* Processor that is doing the boot up */
unsigned int boot_cpu_physical_apicid = -1U;
/* Internal processor count */
-static unsigned int __devinitdata num_processors;
+unsigned int __cpuinitdata num_processors;

/* Bitmask of physically existing CPUs */
physid_mask_t phys_cpu_present_map;
Index: linux/include/asm-i386/smp.h
===================================================================
--- linux.orig/include/asm-i386/smp.h
+++ linux/include/asm-i386/smp.h
@@ -84,6 +84,7 @@ static inline int hard_smp_processor_id(

extern int __cpu_disable(void);
extern void __cpu_die(unsigned int cpu);
+extern unsigned int num_processors;

#endif /* !__ASSEMBLY__ */