processor_core.c revision 46ba51ea8f8639da32c55744b35479fdfb4e7232 
1/*
2 * Copyright (C) 2005 Intel Corporation
3 * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
4 *
5 *	Alex Chiang <achiang@hp.com>
6 *	- Unified x86/ia64 implementations
7 */
8#include <linux/export.h>
9#include <linux/acpi.h>
10#include <acpi/processor.h>
11
12#define _COMPONENT		ACPI_PROCESSOR_COMPONENT
13ACPI_MODULE_NAME("processor_core");
14
15static int map_lapic_id(struct acpi_subtable_header *entry,
16		 u32 acpi_id, int *apic_id)
17{
18	struct acpi_madt_local_apic *lapic =
19		(struct acpi_madt_local_apic *)entry;
20
21	if (!(lapic->lapic_flags & ACPI_MADT_ENABLED))
22		return -ENODEV;
23
24	if (lapic->processor_id != acpi_id)
25		return -EINVAL;
26
27	*apic_id = lapic->id;
28	return 0;
29}
30
31static int map_x2apic_id(struct acpi_subtable_header *entry,
32			 int device_declaration, u32 acpi_id, int *apic_id)
33{
34	struct acpi_madt_local_x2apic *apic =
35		(struct acpi_madt_local_x2apic *)entry;
36
37	if (!(apic->lapic_flags & ACPI_MADT_ENABLED))
38		return -ENODEV;
39
40	if (device_declaration && (apic->uid == acpi_id)) {
41		*apic_id = apic->local_apic_id;
42		return 0;
43	}
44
45	return -EINVAL;
46}
47
48static int map_lsapic_id(struct acpi_subtable_header *entry,
49		int device_declaration, u32 acpi_id, int *apic_id)
50{
51	struct acpi_madt_local_sapic *lsapic =
52		(struct acpi_madt_local_sapic *)entry;
53
54	if (!(lsapic->lapic_flags & ACPI_MADT_ENABLED))
55		return -ENODEV;
56
57	if (device_declaration) {
58		if ((entry->length < 16) || (lsapic->uid != acpi_id))
59			return -EINVAL;
60	} else if (lsapic->processor_id != acpi_id)
61		return -EINVAL;
62
63	*apic_id = (lsapic->id << 8) | lsapic->eid;
64	return 0;
65}
66
67static int map_madt_entry(int type, u32 acpi_id)
68{
69	unsigned long madt_end, entry;
70	static struct acpi_table_madt *madt;
71	static int read_madt;
72	int apic_id = -1;
73
74	if (!read_madt) {
75		if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_MADT, 0,
76					(struct acpi_table_header **)&madt)))
77			madt = NULL;
78		read_madt++;
79	}
80
81	if (!madt)
82		return apic_id;
83
84	entry = (unsigned long)madt;
85	madt_end = entry + madt->header.length;
86
87	/* Parse all entries looking for a match. */
88
89	entry += sizeof(struct acpi_table_madt);
90	while (entry + sizeof(struct acpi_subtable_header) < madt_end) {
91		struct acpi_subtable_header *header =
92			(struct acpi_subtable_header *)entry;
93		if (header->type == ACPI_MADT_TYPE_LOCAL_APIC) {
94			if (!map_lapic_id(header, acpi_id, &apic_id))
95				break;
96		} else if (header->type == ACPI_MADT_TYPE_LOCAL_X2APIC) {
97			if (!map_x2apic_id(header, type, acpi_id, &apic_id))
98				break;
99		} else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
100			if (!map_lsapic_id(header, type, acpi_id, &apic_id))
101				break;
102		}
103		entry += header->length;
104	}
105	return apic_id;
106}
107
108static int map_mat_entry(acpi_handle handle, int type, u32 acpi_id)
109{
110	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
111	union acpi_object *obj;
112	struct acpi_subtable_header *header;
113	int apic_id = -1;
114
115	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
116		goto exit;
117
118	if (!buffer.length || !buffer.pointer)
119		goto exit;
120
121	obj = buffer.pointer;
122	if (obj->type != ACPI_TYPE_BUFFER ||
123	    obj->buffer.length < sizeof(struct acpi_subtable_header)) {
124		goto exit;
125	}
126
127	header = (struct acpi_subtable_header *)obj->buffer.pointer;
128	if (header->type == ACPI_MADT_TYPE_LOCAL_APIC) {
129		map_lapic_id(header, acpi_id, &apic_id);
130	} else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
131		map_lsapic_id(header, type, acpi_id, &apic_id);
132	}
133
134exit:
135	kfree(buffer.pointer);
136	return apic_id;
137}
138
139int acpi_get_apicid(acpi_handle handle, int type, u32 acpi_id)
140{
141	int apic_id;
142
143	apic_id = map_mat_entry(handle, type, acpi_id);
144	if (apic_id == -1)
145		apic_id = map_madt_entry(type, acpi_id);
146
147	return apic_id;
148}
149
150int acpi_map_cpuid(int apic_id, u32 acpi_id)
151{
152#ifdef CONFIG_SMP
153	int i;
154#endif
155
156	if (apic_id == -1) {
157		/*
158		 * On UP processor, there is no _MAT or MADT table.
159		 * So above apic_id is always set to -1.
160		 *
161		 * BIOS may define multiple CPU handles even for UP processor.
162		 * For example,
163		 *
164		 * Scope (_PR)
165                 * {
166		 *     Processor (CPU0, 0x00, 0x00000410, 0x06) {}
167		 *     Processor (CPU1, 0x01, 0x00000410, 0x06) {}
168		 *     Processor (CPU2, 0x02, 0x00000410, 0x06) {}
169		 *     Processor (CPU3, 0x03, 0x00000410, 0x06) {}
170		 * }
171		 *
172		 * Ignores apic_id and always returns 0 for the processor
173		 * handle with acpi id 0 if nr_cpu_ids is 1.
174		 * This should be the case if SMP tables are not found.
175		 * Return -1 for other CPU's handle.
176		 */
177		if (nr_cpu_ids <= 1 && acpi_id == 0)
178			return acpi_id;
179		else
180			return apic_id;
181	}
182
183#ifdef CONFIG_SMP
184	for_each_possible_cpu(i) {
185		if (cpu_physical_id(i) == apic_id)
186			return i;
187	}
188#else
189	/* In UP kernel, only processor 0 is valid */
190	if (apic_id == 0)
191		return apic_id;
192#endif
193	return -1;
194}
195
196int acpi_get_cpuid(acpi_handle handle, int type, u32 acpi_id)
197{
198	int apic_id;
199
200	apic_id = acpi_get_apicid(handle, type, acpi_id);
201
202	return acpi_map_cpuid(apic_id, acpi_id);
203}
204EXPORT_SYMBOL_GPL(acpi_get_cpuid);
205