summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/cpu/topology.c
blob: 0270925fe013bcf9bbe76e589c93a35a6ddbfde5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
// SPDX-License-Identifier: GPL-2.0
/*
 * Check for extended topology enumeration cpuid leaf 0xb and if it
 * exists, use it for populating initial_apicid and cpu topology
 * detection.
 */

#include <linux/cpu.h>
#include <asm/apic.h>
#include <asm/memtype.h>
#include <asm/processor.h>

#include "cpu.h"

/* leaf 0xb SMT level */
#define SMT_LEVEL	0

/* extended topology sub-leaf types */
#define INVALID_TYPE	0
#define SMT_TYPE	1
#define CORE_TYPE	2
#define DIE_TYPE	5

#define LEAFB_SUBTYPE(ecx)		(((ecx) >> 8) & 0xff)
#define BITS_SHIFT_NEXT_LEVEL(eax)	((eax) & 0x1f)
#define LEVEL_MAX_SIBLINGS(ebx)		((ebx) & 0xffff)

unsigned int __max_die_per_package __read_mostly = 1;
EXPORT_SYMBOL(__max_die_per_package);

#ifdef CONFIG_SMP
/*
 * Check if given CPUID extended topology "leaf" is implemented
 */
static int check_extended_topology_leaf(int leaf)
{
	unsigned int eax, ebx, ecx, edx;

	cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);

	if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE))
		return -1;

	return 0;
}
/*
 * Return best CPUID Extended Topology Leaf supported
 */
static int detect_extended_topology_leaf(struct cpuinfo_x86 *c)
{
	if (c->cpuid_level >= 0x1f) {
		if (check_extended_topology_leaf(0x1f) == 0)
			return 0x1f;
	}

	if (c->cpuid_level >= 0xb) {
		if (check_extended_topology_leaf(0xb) == 0)
			return 0xb;
	}

	return -1;
}
#endif

int detect_extended_topology_early(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_SMP
	unsigned int eax, ebx, ecx, edx;
	int leaf;

	leaf = detect_extended_topology_leaf(c);
	if (leaf < 0)
		return -1;

	set_cpu_cap(c, X86_FEATURE_XTOPOLOGY);

	cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
	/*
	 * initial apic id, which also represents 32-bit extended x2apic id.
	 */
	c->initial_apicid = edx;
	smp_num_siblings = max_t(int, smp_num_siblings, LEVEL_MAX_SIBLINGS(ebx));
#endif
	return 0;
}

/*
 * Check for extended topology enumeration cpuid leaf, and if it
 * exists, use it for populating initial_apicid and cpu topology
 * detection.
 */
int detect_extended_topology(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_SMP
	unsigned int eax, ebx, ecx, edx, sub_index;
	unsigned int ht_mask_width, core_plus_mask_width, die_plus_mask_width;
	unsigned int core_select_mask, core_level_siblings;
	unsigned int die_select_mask, die_level_siblings;
	unsigned int pkg_mask_width;
	bool die_level_present = false;
	int leaf;

	leaf = detect_extended_topology_leaf(c);
	if (leaf < 0)
		return -1;

	/*
	 * Populate HT related information from sub-leaf level 0.
	 */
	cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
	c->initial_apicid = edx;
	core_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
	smp_num_siblings = max_t(int, smp_num_siblings, LEVEL_MAX_SIBLINGS(ebx));
	core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
	die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
	pkg_mask_width = die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);

	sub_index = 1;
	while (true) {
		cpuid_count(leaf, sub_index, &eax, &ebx, &ecx, &edx);

		/*
		 * Check for the Core type in the implemented sub leaves.
		 */
		if (LEAFB_SUBTYPE(ecx) == CORE_TYPE) {
			core_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
			core_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
			die_level_siblings = core_level_siblings;
			die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
		}
		if (LEAFB_SUBTYPE(ecx) == DIE_TYPE) {
			die_level_present = true;
			die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
			die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
		}

		if (LEAFB_SUBTYPE(ecx) != INVALID_TYPE)
			pkg_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
		else
			break;

		sub_index++;
	}

	core_select_mask = (~(-1 << pkg_mask_width)) >> ht_mask_width;
	die_select_mask = (~(-1 << die_plus_mask_width)) >>
				core_plus_mask_width;

	c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid,
				ht_mask_width) & core_select_mask;

	if (die_level_present) {
		c->cpu_die_id = apic->phys_pkg_id(c->initial_apicid,
					core_plus_mask_width) & die_select_mask;
	}

	c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid,
				pkg_mask_width);
	/*
	 * Reinit the apicid, now that we have extended initial_apicid.
	 */
	c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);

	c->x86_max_cores = (core_level_siblings / smp_num_siblings);
	__max_die_per_package = (die_level_siblings / core_level_siblings);
#endif
	return 0;
}