1 /*
2 * Check for extended topology enumeration cpuid leaf 0xb and if it
3 * exists, use it for populating initial_apicid and cpu topology
4 * detection.
5 */
6
7 #include <linux/cpu.h>
8 #include <asm/apic.h>
9 #include <asm/pat.h>
10 #include <asm/processor.h>
11
12 /* leaf 0xb SMT level */
13 #define SMT_LEVEL 0
14
15 /* leaf 0xb sub-leaf types */
16 #define INVALID_TYPE 0
17 #define SMT_TYPE 1
18 #define CORE_TYPE 2
19
20 #define LEAFB_SUBTYPE(ecx) (((ecx) >> 8) & 0xff)
21 #define BITS_SHIFT_NEXT_LEVEL(eax) ((eax) & 0x1f)
22 #define LEVEL_MAX_SIBLINGS(ebx) ((ebx) & 0xffff)
23
24 /*
25 * Check for extended topology enumeration cpuid leaf 0xb and if it
26 * exists, use it for populating initial_apicid and cpu topology
27 * detection.
28 */
detect_extended_topology(struct cpuinfo_x86 * c)29 void __cpuinit detect_extended_topology(struct cpuinfo_x86 *c)
30 {
31 #ifdef CONFIG_SMP
32 unsigned int eax, ebx, ecx, edx, sub_index;
33 unsigned int ht_mask_width, core_plus_mask_width;
34 unsigned int core_select_mask, core_level_siblings;
35 static bool printed;
36
37 if (c->cpuid_level < 0xb)
38 return;
39
40 cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
41
42 /*
43 * check if the cpuid leaf 0xb is actually implemented.
44 */
45 if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE))
46 return;
47
48 set_cpu_cap(c, X86_FEATURE_XTOPOLOGY);
49
50 /*
51 * initial apic id, which also represents 32-bit extended x2apic id.
52 */
53 c->initial_apicid = edx;
54
55 /*
56 * Populate HT related information from sub-leaf level 0.
57 */
58 core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx);
59 core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
60
61 sub_index = 1;
62 do {
63 cpuid_count(0xb, sub_index, &eax, &ebx, &ecx, &edx);
64
65 /*
66 * Check for the Core type in the implemented sub leaves.
67 */
68 if (LEAFB_SUBTYPE(ecx) == CORE_TYPE) {
69 core_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
70 core_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
71 break;
72 }
73
74 sub_index++;
75 } while (LEAFB_SUBTYPE(ecx) != INVALID_TYPE);
76
77 core_select_mask = (~(-1 << core_plus_mask_width)) >> ht_mask_width;
78
79 c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, ht_mask_width)
80 & core_select_mask;
81 c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, core_plus_mask_width);
82 /*
83 * Reinit the apicid, now that we have extended initial_apicid.
84 */
85 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
86
87 c->x86_max_cores = (core_level_siblings / smp_num_siblings);
88
89 if (!printed) {
90 printk(KERN_INFO "CPU: Physical Processor ID: %d\n",
91 c->phys_proc_id);
92 if (c->x86_max_cores > 1)
93 printk(KERN_INFO "CPU: Processor Core ID: %d\n",
94 c->cpu_core_id);
95 printed = 1;
96 }
97 return;
98 #endif
99 }
100