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Commit 05131ecc authored by Venkatesh Pallipadi's avatar Venkatesh Pallipadi Committed by Len Brown
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[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: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent d2149b54

arch/i386/kernel/acpi/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -3,6 +3,6 @@ obj-$(CONFIG_X86_IO_APIC) += earlyquirk.o 
obj-$(CONFIG_ACPI_SLEEP)	+= sleep.o wakeup.o



ifneq ($(CONFIG_ACPI_PROCESSOR),)

obj-y				+= cstate.o

obj-y				+= cstate.o processor.o

endif

arch/i386/kernel/acpi/cstate.c

+0 −58
Original line number Diff line number Diff line
@@ -14,64 +14,6 @@ 
#include <acpi/processor.h>

#include <asm/acpi.h>



static void acpi_processor_power_init_intel_pdc(struct acpi_processor_power

						*pow)

{

	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;



	obj->type = ACPI_TYPE_BUFFER;

	obj->buffer.length = 12;

	obj->buffer.pointer = (u8 *) buf;

	obj_list->count = 1;

	obj_list->pointer = obj;

	pow->pdc = obj_list;



	return;

}



/* Initialize _PDC data based on the CPU vendor */

void acpi_processor_power_init_pdc(struct acpi_processor_power *pow,

				   unsigned int cpu)

{

	struct cpuinfo_x86 *c = cpu_data + cpu;



	pow->pdc = NULL;

	if (c->x86_vendor == X86_VENDOR_INTEL)

		acpi_processor_power_init_intel_pdc(pow);



	return;

}



EXPORT_SYMBOL(acpi_processor_power_init_pdc);



/*

 * Initialize bm_flags based on the CPU cache properties

 * On SMP it depends on cache configuration

arch/i386/kernel/acpi/processor.c

0 → 100644
+75 −0
Original line number Diff line number Diff line 
/*

 * 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);

arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c

+0 −67
Original line number Diff line number Diff line
@@ -297,68 +297,6 @@ acpi_cpufreq_guess_freq ( 
}





/* 

 * acpi_processor_cpu_init_pdc_est - let BIOS know about the SMP capabilities

 * of this driver

 * @perf: processor-specific acpi_io_data struct

 * @cpu: CPU being initialized

 *

 * To avoid issues with legacy OSes, some BIOSes require to be informed of

 * the SMP capabilities of OS P-state driver. Here we set the bits in _PDC 

 * accordingly, for Enhanced Speedstep. Actual call to _PDC is done in

 * driver/acpi/processor.c

 */

static void 

acpi_processor_cpu_init_pdc_est(

		struct acpi_processor_performance *perf, 

		unsigned int cpu,

		struct acpi_object_list *obj_list

		)

{

	union acpi_object *obj;

	u32 *buf;

	struct cpuinfo_x86 *c = cpu_data + cpu;

	dprintk("acpi_processor_cpu_init_pdc_est\n");



	if (!cpu_has(c, X86_FEATURE_EST))

		return;



	/* Initialize pdc. It will be used later. */

	if (!obj_list)

		return;

		

	if (!(obj_list->count && obj_list->pointer))

		return;



	obj = obj_list->pointer;

	if ((obj->buffer.length == 12) && obj->buffer.pointer) {

		buf = (u32 *)obj->buffer.pointer;

       		buf[0] = ACPI_PDC_REVISION_ID;

       		buf[1] = 1;

       		buf[2] = ACPI_PDC_EST_CAPABILITY_SMP;

		perf->pdc = obj_list;

	}

	return;

}

 



/* CPU specific PDC initialization */

static void 

acpi_processor_cpu_init_pdc(

		struct acpi_processor_performance *perf, 

		unsigned int cpu,

		struct acpi_object_list *obj_list

		)

{

	struct cpuinfo_x86 *c = cpu_data + cpu;

	dprintk("acpi_processor_cpu_init_pdc\n");

	perf->pdc = NULL;

	if (cpu_has(c, X86_FEATURE_EST))

		acpi_processor_cpu_init_pdc_est(perf, cpu, obj_list);

	return;

}





static int

acpi_cpufreq_cpu_init (

	struct cpufreq_policy   *policy)
@@ -373,9 +311,6 @@ acpi_cpufreq_cpu_init ( 
	struct acpi_object_list 	arg_list = {1, &arg0};



	dprintk("acpi_cpufreq_cpu_init\n");

	/* setup arg_list for _PDC settings */

        arg0.buffer.length = 12;

        arg0.buffer.pointer = (u8 *) arg0_buf;



	data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);

	if (!data)
@@ -383,9 +318,7 @@ acpi_cpufreq_cpu_init ( 


	acpi_io_data[cpu] = data;



	acpi_processor_cpu_init_pdc(&data->acpi_data, cpu, &arg_list);

	result = acpi_processor_register_performance(&data->acpi_data, cpu);

	data->acpi_data.pdc = NULL;



	if (result)

		goto err_free;

arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c

+0 −12
Original line number Diff line number Diff line
@@ -364,22 +364,10 @@ static struct acpi_processor_performance p; 
 */

static int centrino_cpu_init_acpi(struct cpufreq_policy *policy)

{

	union acpi_object		arg0 = {ACPI_TYPE_BUFFER};

	u32				arg0_buf[3];

	struct acpi_object_list		arg_list = {1, &arg0};

	unsigned long			cur_freq;

	int				result = 0, i;

	unsigned int			cpu = policy->cpu;



	/* _PDC settings */

	arg0.buffer.length = 12;

	arg0.buffer.pointer = (u8 *) arg0_buf;

	arg0_buf[0] = ACPI_PDC_REVISION_ID;

	arg0_buf[1] = 1;

	arg0_buf[2] = ACPI_PDC_EST_CAPABILITY_SMP_MSR;



	p.pdc = &arg_list;



	/* register with ACPI core */

	if (acpi_processor_register_performance(&p, cpu)) {

		dprintk(KERN_INFO PFX "obtaining ACPI data failed\n");