processor_core.c

/*
 * Copyright (C) 2005 Intel Corporation
 * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
 *
 *	Alex Chiang <achiang@hp.com>
 *	- Unified x86/ia64 implementations
 *	Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 *	- Added _PDC for platforms with Intel CPUs
 */
#include <linux/export.h>
#include <linux/dmi.h>
#include <linux/slab.h>

#include <acpi/acpi_drivers.h>
#include <acpi/processor.h>

#include "internal.h"

#define PREFIX			"ACPI: "
#define _COMPONENT		ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_core");

static int __init set_no_mwait(const struct dmi_system_id *id)
{
	printk(KERN_NOTICE PREFIX "%s detected - "
		"disabling mwait for CPU C-states\n", id->ident);
	boot_option_idle_override = IDLE_NOMWAIT;
	return 0;
}

static struct dmi_system_id processor_idle_dmi_table[] __initdata = {
	{
	set_no_mwait, "Extensa 5220", {
	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
	DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
	DMI_MATCH(DMI_PRODUCT_VERSION, "0100"),
	DMI_MATCH(DMI_BOARD_NAME, "Columbia") }, NULL},
	{},
};

static int map_lapic_id(struct acpi_subtable_header *entry,
		 u32 acpi_id, int *apic_id)
{
	struct acpi_madt_local_apic *lapic =
		(struct acpi_madt_local_apic *)entry;

	if (!(lapic->lapic_flags & ACPI_MADT_ENABLED))
		return 0;

	if (lapic->processor_id != acpi_id)
		return 0;

	*apic_id = lapic->id;
	return 1;
}

static int map_x2apic_id(struct acpi_subtable_header *entry,
			 int device_declaration, u32 acpi_id, int *apic_id)
{
	struct acpi_madt_local_x2apic *apic =
		(struct acpi_madt_local_x2apic *)entry;

	if (!(apic->lapic_flags & ACPI_MADT_ENABLED))
		return 0;

	if (device_declaration && (apic->uid == acpi_id)) {
		*apic_id = apic->local_apic_id;
		return 1;
	}

	return 0;
}

static int map_lsapic_id(struct acpi_subtable_header *entry,
		int device_declaration, u32 acpi_id, int *apic_id)
{
	struct acpi_madt_local_sapic *lsapic =
		(struct acpi_madt_local_sapic *)entry;

	if (!(lsapic->lapic_flags & ACPI_MADT_ENABLED))
		return 0;

	if (device_declaration) {
		if ((entry->length < 16) || (lsapic->uid != acpi_id))
			return 0;
	} else if (lsapic->processor_id != acpi_id)
		return 0;

	*apic_id = (lsapic->id << 8) | lsapic->eid;
	return 1;
}

static int map_madt_entry(int type, u32 acpi_id)
{
	unsigned long madt_end, entry;
	static struct acpi_table_madt *madt;
	static int read_madt;
	int apic_id = -1;

	if (!read_madt) {
		if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_MADT, 0,
					(struct acpi_table_header **)&madt)))
			madt = NULL;
		read_madt++;
	}

	if (!madt)
		return apic_id;

	entry = (unsigned long)madt;
	madt_end = entry + madt->header.length;

	/* Parse all entries looking for a match. */

	entry += sizeof(struct acpi_table_madt);
	while (entry + sizeof(struct acpi_subtable_header) < madt_end) {
		struct acpi_subtable_header *header =
			(struct acpi_subtable_header *)entry;
		if (header->type == ACPI_MADT_TYPE_LOCAL_APIC) {
			if (map_lapic_id(header, acpi_id, &apic_id))
				break;
		} else if (header->type == ACPI_MADT_TYPE_LOCAL_X2APIC) {
			if (map_x2apic_id(header, type, acpi_id, &apic_id))
				break;
		} else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
			if (map_lsapic_id(header, type, acpi_id, &apic_id))
				break;
		}
		entry += header->length;
	}
	return apic_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;
	struct acpi_subtable_header *header;
	int apic_id = -1;

	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
		goto exit;

	if (!buffer.length || !buffer.pointer)
		goto exit;

	obj = buffer.pointer;
	if (obj->type != ACPI_TYPE_BUFFER ||
	    obj->buffer.length < sizeof(struct acpi_subtable_header)) {
		goto exit;
	}

	header = (struct acpi_subtable_header *)obj->buffer.pointer;
	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, type, acpi_id, &apic_id);
	}

exit:
	kfree(buffer.pointer);
	return apic_id;
}

int acpi_get_cpuid(acpi_handle handle, int type, u32 acpi_id)
{
#ifdef CONFIG_SMP
	int i;
#endif
	int apic_id = -1;

	apic_id = map_mat_entry(handle, type, acpi_id);
	if (apic_id == -1)
		apic_id = map_madt_entry(type, acpi_id);
	if (apic_id == -1) {
		/*
		 * On UP processor, there is no _MAT or MADT table.
		 * So above apic_id is always set to -1.
		 *
		 * BIOS may define multiple CPU handles even for UP processor.
		 * For example,
		 *
		 * Scope (_PR)
                 * {
		 *     Processor (CPU0, 0x00, 0x00000410, 0x06) {}
		 *     Processor (CPU1, 0x01, 0x00000410, 0x06) {}
		 *     Processor (CPU2, 0x02, 0x00000410, 0x06) {}
		 *     Processor (CPU3, 0x03, 0x00000410, 0x06) {}
		 * }
		 *
		 * Ignores apic_id and always returns 0 for the processor
		 * handle with acpi id 0 if nr_cpu_ids is 1.
		 * This should be the case if SMP tables are not found.
		 * Return -1 for other CPU's handle.
		 */
		if (nr_cpu_ids <= 1 && acpi_id == 0)
			return acpi_id;
		else
			return apic_id;
	}

#ifdef CONFIG_SMP
	for_each_possible_cpu(i) {
		if (cpu_physical_id(i) == apic_id)
			return i;
	}
#else
	/* In UP kernel, only processor 0 is valid */
	if (apic_id == 0)
		return apic_id;
#endif
	return -1;
}
EXPORT_SYMBOL_GPL(acpi_get_cpuid);

static bool __init processor_physically_present(acpi_handle handle)
{
	int cpuid, type;
	u32 acpi_id;
	acpi_status status;
	acpi_object_type acpi_type;
	unsigned long long tmp;
	union acpi_object object = { 0 };
	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };

	status = acpi_get_type(handle, &acpi_type);
	if (ACPI_FAILURE(status))
		return false;

	switch (acpi_type) {
	case ACPI_TYPE_PROCESSOR:
		status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
		if (ACPI_FAILURE(status))
			return false;
		acpi_id = object.processor.proc_id;
		break;
	case ACPI_TYPE_DEVICE:
		status = acpi_evaluate_integer(handle, "_UID", NULL, &tmp);
		if (ACPI_FAILURE(status))
			return false;
		acpi_id = tmp;
		break;
	default:
		return false;
	}

	type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
	cpuid = acpi_get_cpuid(handle, type, acpi_id);

	if (cpuid == -1)
		return false;

	return true;
}

static void acpi_set_pdc_bits(u32 *buf)
{
	buf[0] = ACPI_PDC_REVISION_ID;
	buf[1] = 1;

	/* Enable coordination with firmware's _TSD info */
	buf[2] = ACPI_PDC_SMP_T_SWCOORD;

	/* Twiddle arch-specific bits needed for _PDC */
	arch_acpi_set_pdc_bits(buf);
}

static struct acpi_object_list *acpi_processor_alloc_pdc(void)
{
	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 NULL;
	}

	obj = kmalloc(sizeof(union acpi_object), GFP_KERNEL);
	if (!obj) {
		printk(KERN_ERR "Memory allocation error\n");
		kfree(obj_list);
		return NULL;
	}

	buf = kmalloc(12, GFP_KERNEL);
	if (!buf) {
		printk(KERN_ERR "Memory allocation error\n");
		kfree(obj);
		kfree(obj_list);
		return NULL;
	}

	acpi_set_pdc_bits(buf);

	obj->type = ACPI_TYPE_BUFFER;
	obj->buffer.length = 12;
	obj->buffer.pointer = (u8 *) buf;
	obj_list->count = 1;
	obj_list->pointer = obj;

	return obj_list;
}

/*
 * _PDC is required for a BIOS-OS handshake for most of the newer
 * ACPI processor features.
 */
static int
acpi_processor_eval_pdc(acpi_handle handle, struct acpi_object_list *pdc_in)
{
	acpi_status status = AE_OK;

	if (boot_option_idle_override == IDLE_NOMWAIT) {
		/*
		 * If mwait is disabled for CPU C-states, the C2C3_FFH access
		 * mode will be disabled in the parameter of _PDC object.
		 * Of course C1_FFH access mode will also be disabled.
		 */
		union acpi_object *obj;
		u32 *buffer = NULL;

		obj = pdc_in->pointer;
		buffer = (u32 *)(obj->buffer.pointer);
		buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH | ACPI_PDC_C_C1_FFH);

	}
	status = acpi_evaluate_object(handle, "_PDC", pdc_in, NULL);

	if (ACPI_FAILURE(status))
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
		    "Could not evaluate _PDC, using legacy perf. control.\n"));

	return status;
}

void acpi_processor_set_pdc(acpi_handle handle)
{
	struct acpi_object_list *obj_list;

	if (arch_has_acpi_pdc() == false)
		return;

	obj_list = acpi_processor_alloc_pdc();
	if (!obj_list)
		return;

	acpi_processor_eval_pdc(handle, obj_list);

	kfree(obj_list->pointer->buffer.pointer);
	kfree(obj_list->pointer);
	kfree(obj_list);
}

static acpi_status __init
early_init_pdc(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	if (processor_physically_present(handle) == false)
		return AE_OK;

	acpi_processor_set_pdc(handle);
	return AE_OK;
}

void __init acpi_early_processor_set_pdc(void)
{
	/*
	 * Check whether the system is DMI table. If yes, OSPM
	 * should not use mwait for CPU-states.
	 */
	dmi_check_system(processor_idle_dmi_table);

	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
			    ACPI_UINT32_MAX,
			    early_init_pdc, NULL, NULL, NULL);
	acpi_get_devices("ACPI0007", early_init_pdc, NULL, NULL);
}