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 = 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 = 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);
116 
117 	sub_index = 1;
118 	while (true) {
119 		cpuid_count(leaf, sub_index, &eax, &ebx, &ecx, &edx);
120 
121 		/*
122 		 * Check for the Core type in the implemented sub leaves.
123 		 */
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);
129 		}
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);
134 		}
135 
136 		if (LEAFB_SUBTYPE(ecx) != INVALID_TYPE)
137 			pkg_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
138 		else
139 			break;
140 
141 		sub_index++;
142 	}
143 
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;
147 
148 	c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid,
149 				ht_mask_width) & core_select_mask;
150 
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;
154 	}
155 
156 	c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid,
157 				pkg_mask_width);
158 	/*
159 	 * Reinit the apicid, now that we have extended initial_apicid.
160 	 */
161 	c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
162 
163 	c->x86_max_cores = (core_level_siblings / smp_num_siblings);
164 	__max_die_per_package = (die_level_siblings / core_level_siblings);
165 #endif
166 	return 0;
167 }
168