1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Check for extended topology enumeration cpuid leaf 0xb and if it
4 * exists, use it for populating initial_apicid and cpu topology
5 * detection.
6 */
7
8 #include <linux/cpu.h>
9 #include <asm/apic.h>
10 #include <asm/memtype.h>
11 #include <asm/processor.h>
12
13 #include "cpu.h"
14
15 /* leaf 0xb SMT level */
16 #define SMT_LEVEL 0
17
18 /* extended topology sub-leaf types */
19 #define INVALID_TYPE 0
20 #define SMT_TYPE 1
21 #define CORE_TYPE 2
22 #define DIE_TYPE 5
23
24 #define LEAFB_SUBTYPE(ecx) (((ecx) >> 8) & 0xff)
25 #define BITS_SHIFT_NEXT_LEVEL(eax) ((eax) & 0x1f)
26 #define LEVEL_MAX_SIBLINGS(ebx) ((ebx) & 0xffff)
27
28 unsigned int __max_die_per_package __read_mostly = 1;
29 EXPORT_SYMBOL(__max_die_per_package);
30
31 #ifdef CONFIG_SMP
32 /*
33 * Check if given CPUID extended topology "leaf" is implemented
34 */
check_extended_topology_leaf(int leaf)35 static int check_extended_topology_leaf(int leaf)
36 {
37 unsigned int eax, ebx, ecx, edx;
38
39 cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
40
41 if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE))
42 return -1;
43
44 return 0;
45 }
46 /*
47 * Return best CPUID Extended Topology Leaf supported
48 */
detect_extended_topology_leaf(struct cpuinfo_x86 * c)49 static int detect_extended_topology_leaf(struct cpuinfo_x86 *c)
50 {
51 if (c->cpuid_level >= 0x1f) {
52 if (check_extended_topology_leaf(0x1f) == 0)
53 return 0x1f;
54 }
55
56 if (c->cpuid_level >= 0xb) {
57 if (check_extended_topology_leaf(0xb) == 0)
58 return 0xb;
59 }
60
61 return -1;
62 }
63 #endif
64
detect_extended_topology_early(struct cpuinfo_x86 * c)65 int detect_extended_topology_early(struct cpuinfo_x86 *c)
66 {
67 #ifdef CONFIG_SMP
68 unsigned int eax, ebx, ecx, edx;
69 int leaf;
70
71 leaf = detect_extended_topology_leaf(c);
72 if (leaf < 0)
73 return -1;
74
75 set_cpu_cap(c, X86_FEATURE_XTOPOLOGY);
76
77 cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
78 /*
79 * initial apic id, which also represents 32-bit extended x2apic id.
80 */
81 c->initial_apicid = edx;
82 smp_num_siblings = max_t(int, smp_num_siblings, LEVEL_MAX_SIBLINGS(ebx));
83 #endif
84 return 0;
85 }
86
87 /*
88 * Check for extended topology enumeration cpuid leaf, and if it
89 * exists, use it for populating initial_apicid and cpu topology
90 * detection.
91 */
detect_extended_topology(struct cpuinfo_x86 * c)92 int detect_extended_topology(struct cpuinfo_x86 *c)
93 {
94 #ifdef CONFIG_SMP
95 unsigned int eax, ebx, ecx, edx, sub_index;
96 unsigned int ht_mask_width, core_plus_mask_width, die_plus_mask_width;
97 unsigned int core_select_mask, core_level_siblings;
98 unsigned int die_select_mask, die_level_siblings;
99 unsigned int pkg_mask_width;
100 bool die_level_present = false;
101 int leaf;
102
103 leaf = detect_extended_topology_leaf(c);
104 if (leaf < 0)
105 return -1;
106
107 /*
108 * Populate HT related information from sub-leaf level 0.
109 */
110 cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
111 c->initial_apicid = edx;
112 core_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
113 smp_num_siblings = max_t(int, smp_num_siblings, LEVEL_MAX_SIBLINGS(ebx));
114 core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
115 die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
116 pkg_mask_width = die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
117
118 sub_index = 1;
119 while (true) {
120 cpuid_count(leaf, sub_index, &eax, &ebx, &ecx, &edx);
121
122 /*
123 * Check for the Core type in the implemented sub leaves.
124 */
125 if (LEAFB_SUBTYPE(ecx) == CORE_TYPE) {
126 core_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
127 core_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
128 die_level_siblings = core_level_siblings;
129 die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
130 }
131 if (LEAFB_SUBTYPE(ecx) == DIE_TYPE) {
132 die_level_present = true;
133 die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
134 die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
135 }
136
137 if (LEAFB_SUBTYPE(ecx) != INVALID_TYPE)
138 pkg_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
139 else
140 break;
141
142 sub_index++;
143 }
144
145 core_select_mask = (~(-1 << pkg_mask_width)) >> ht_mask_width;
146 die_select_mask = (~(-1 << die_plus_mask_width)) >>
147 core_plus_mask_width;
148
149 c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid,
150 ht_mask_width) & core_select_mask;
151
152 if (die_level_present) {
153 c->cpu_die_id = apic->phys_pkg_id(c->initial_apicid,
154 core_plus_mask_width) & die_select_mask;
155 }
156
157 c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid,
158 pkg_mask_width);
159 /*
160 * Reinit the apicid, now that we have extended initial_apicid.
161 */
162 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
163
164 c->x86_max_cores = (core_level_siblings / smp_num_siblings);
165 __max_die_per_package = (die_level_siblings / core_level_siblings);
166 #endif
167 return 0;
168 }
169