1 // SPDX-License-Identifier: GPL-2.0
3 * Check for extended topology enumeration cpuid leaf 0xb and if it
4 * exists, use it for populating initial_apicid and cpu topology
10 #include <asm/memtype.h>
11 #include <asm/processor.h>
15 /* leaf 0xb SMT level */
18 /* extended topology sub-leaf types */
19 #define INVALID_TYPE 0
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)
28 unsigned int __max_die_per_package __read_mostly = 1;
29 EXPORT_SYMBOL(__max_die_per_package);
33 * Check if given CPUID extended topology "leaf" is implemented
35 static int check_extended_topology_leaf(int leaf)
37 unsigned int eax, ebx, ecx, edx;
39 cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
41 if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE))
47 * Return best CPUID Extended Topology Leaf supported
49 static int detect_extended_topology_leaf(struct cpuinfo_x86 *c)
51 if (c->cpuid_level >= 0x1f) {
52 if (check_extended_topology_leaf(0x1f) == 0)
56 if (c->cpuid_level >= 0xb) {
57 if (check_extended_topology_leaf(0xb) == 0)
65 int detect_extended_topology_early(struct cpuinfo_x86 *c)
68 unsigned int eax, ebx, ecx, edx;
71 leaf = detect_extended_topology_leaf(c);
75 set_cpu_cap(c, X86_FEATURE_XTOPOLOGY);
77 cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
79 * initial apic id, which also represents 32-bit extended x2apic id.
81 c->initial_apicid = edx;
82 smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx);
88 * Check for extended topology enumeration cpuid leaf, and if it
89 * exists, use it for populating initial_apicid and cpu topology
92 int detect_extended_topology(struct cpuinfo_x86 *c)
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;
103 leaf = detect_extended_topology_leaf(c);
108 * Populate HT related information from sub-leaf level 0.
110 cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
111 c->initial_apicid = edx;
112 core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx);
113 core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
114 die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
115 pkg_mask_width = die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
119 cpuid_count(leaf, sub_index, &eax, &ebx, &ecx, &edx);
122 * Check for the Core type in the implemented sub leaves.
124 if (LEAFB_SUBTYPE(ecx) == CORE_TYPE) {
125 core_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
126 core_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
127 die_level_siblings = core_level_siblings;
128 die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
130 if (LEAFB_SUBTYPE(ecx) == DIE_TYPE) {
131 die_level_present = true;
132 die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
133 die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
136 if (LEAFB_SUBTYPE(ecx) != INVALID_TYPE)
137 pkg_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
144 core_select_mask = (~(-1 << pkg_mask_width)) >> ht_mask_width;
145 die_select_mask = (~(-1 << die_plus_mask_width)) >>
146 core_plus_mask_width;
148 c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid,
149 ht_mask_width) & core_select_mask;
151 if (die_level_present) {
152 c->cpu_die_id = apic->phys_pkg_id(c->initial_apicid,
153 core_plus_mask_width) & die_select_mask;
156 c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid,
159 * Reinit the apicid, now that we have extended initial_apicid.
161 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
163 c->x86_max_cores = (core_level_siblings / smp_num_siblings);
164 __max_die_per_package = (die_level_siblings / core_level_siblings);