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 bool die_level_present
= false;
102 leaf
= detect_extended_topology_leaf(c
);
107 * Populate HT related information from sub-leaf level 0.
109 cpuid_count(leaf
, SMT_LEVEL
, &eax
, &ebx
, &ecx
, &edx
);
110 c
->initial_apicid
= edx
;
111 core_level_siblings
= smp_num_siblings
= LEVEL_MAX_SIBLINGS(ebx
);
112 core_plus_mask_width
= ht_mask_width
= BITS_SHIFT_NEXT_LEVEL(eax
);
113 die_level_siblings
= LEVEL_MAX_SIBLINGS(ebx
);
114 die_plus_mask_width
= BITS_SHIFT_NEXT_LEVEL(eax
);
118 cpuid_count(leaf
, sub_index
, &eax
, &ebx
, &ecx
, &edx
);
121 * Check for the Core type in the implemented sub leaves.
123 if (LEAFB_SUBTYPE(ecx
) == CORE_TYPE
) {
124 core_level_siblings
= LEVEL_MAX_SIBLINGS(ebx
);
125 core_plus_mask_width
= BITS_SHIFT_NEXT_LEVEL(eax
);
126 die_level_siblings
= core_level_siblings
;
127 die_plus_mask_width
= BITS_SHIFT_NEXT_LEVEL(eax
);
129 if (LEAFB_SUBTYPE(ecx
) == DIE_TYPE
) {
130 die_level_present
= true;
131 die_level_siblings
= LEVEL_MAX_SIBLINGS(ebx
);
132 die_plus_mask_width
= BITS_SHIFT_NEXT_LEVEL(eax
);
136 } while (LEAFB_SUBTYPE(ecx
) != INVALID_TYPE
);
138 core_select_mask
= (~(-1 << core_plus_mask_width
)) >> ht_mask_width
;
139 die_select_mask
= (~(-1 << die_plus_mask_width
)) >>
140 core_plus_mask_width
;
142 c
->cpu_core_id
= apic
->phys_pkg_id(c
->initial_apicid
,
143 ht_mask_width
) & core_select_mask
;
145 if (die_level_present
) {
146 c
->cpu_die_id
= apic
->phys_pkg_id(c
->initial_apicid
,
147 core_plus_mask_width
) & die_select_mask
;
150 c
->phys_proc_id
= apic
->phys_pkg_id(c
->initial_apicid
,
151 die_plus_mask_width
);
153 * Reinit the apicid, now that we have extended initial_apicid.
155 c
->apicid
= apic
->phys_pkg_id(c
->initial_apicid
, 0);
157 c
->x86_max_cores
= (core_level_siblings
/ smp_num_siblings
);
158 __max_die_per_package
= (die_level_siblings
/ core_level_siblings
);