kernel-ark/arch/i386/kernel/acpi/processor.c
Venkatesh Pallipadi 05131ecc99 [ACPI] Avoid BIOS inflicted crashes by evaluating _PDC only once
Linux invokes the AML _PDC method (Processor Driver Capabilities)
to tell the BIOS what features it can handle.  While the ACPI
spec says nothing about the OS invoking _PDC multiple times,
doing so with changing bits seems to hopelessly confuse the BIOS
on multiple platforms up to and including crashing the system.

Factor out the _PDC invocation so Linux invokes it only once.

http://bugzilla.kernel.org/show_bug.cgi?id=5483

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2005-12-01 01:30:35 -05:00

76 lines
1.6 KiB
C

/*
* arch/i386/kernel/acpi/processor.c
*
* Copyright (C) 2005 Intel Corporation
* Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
* - Added _PDC for platforms with Intel CPUs
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <acpi/processor.h>
#include <asm/acpi.h>
static void init_intel_pdc(struct acpi_processor *pr, struct cpuinfo_x86 *c)
{
struct acpi_object_list *obj_list;
union acpi_object *obj;
u32 *buf;
/* allocate and initialize pdc. It will be used later. */
obj_list = kmalloc(sizeof(struct acpi_object_list), GFP_KERNEL);
if (!obj_list) {
printk(KERN_ERR "Memory allocation error\n");
return;
}
obj = kmalloc(sizeof(union acpi_object), GFP_KERNEL);
if (!obj) {
printk(KERN_ERR "Memory allocation error\n");
kfree(obj_list);
return;
}
buf = kmalloc(12, GFP_KERNEL);
if (!buf) {
printk(KERN_ERR "Memory allocation error\n");
kfree(obj);
kfree(obj_list);
return;
}
buf[0] = ACPI_PDC_REVISION_ID;
buf[1] = 1;
buf[2] = ACPI_PDC_C_CAPABILITY_SMP;
if (cpu_has(c, X86_FEATURE_EST))
buf[2] |= ACPI_PDC_EST_CAPABILITY_SMP;
obj->type = ACPI_TYPE_BUFFER;
obj->buffer.length = 12;
obj->buffer.pointer = (u8 *) buf;
obj_list->count = 1;
obj_list->pointer = obj;
pr->pdc = obj_list;
return;
}
/* Initialize _PDC data based on the CPU vendor */
void arch_acpi_processor_init_pdc(struct acpi_processor *pr)
{
unsigned int cpu = pr->id;
struct cpuinfo_x86 *c = cpu_data + cpu;
pr->pdc = NULL;
if (c->x86_vendor == X86_VENDOR_INTEL)
init_intel_pdc(pr, c);
return;
}
EXPORT_SYMBOL(arch_acpi_processor_init_pdc);