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/pat.h> 11 #include <asm/processor.h> 12 13 /* leaf 0xb SMT level */ 14 #define SMT_LEVEL 0 15 16 /* leaf 0xb sub-leaf types */ 17 #define INVALID_TYPE 0 18 #define SMT_TYPE 1 19 #define CORE_TYPE 2 20 21 #define LEAFB_SUBTYPE(ecx) (((ecx) >> 8) & 0xff) 22 #define BITS_SHIFT_NEXT_LEVEL(eax) ((eax) & 0x1f) 23 #define LEVEL_MAX_SIBLINGS(ebx) ((ebx) & 0xffff) 24 25 int detect_extended_topology_early(struct cpuinfo_x86 *c) 26 { 27 #ifdef CONFIG_SMP 28 unsigned int eax, ebx, ecx, edx; 29 30 if (c->cpuid_level < 0xb) 31 return -1; 32 33 cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx); 34 35 /* 36 * check if the cpuid leaf 0xb is actually implemented. 37 */ 38 if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE)) 39 return -1; 40 41 set_cpu_cap(c, X86_FEATURE_XTOPOLOGY); 42 43 /* 44 * initial apic id, which also represents 32-bit extended x2apic id. 45 */ 46 c->initial_apicid = edx; 47 smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx); 48 #endif 49 return 0; 50 } 51 52 /* 53 * Check for extended topology enumeration cpuid leaf 0xb and if it 54 * exists, use it for populating initial_apicid and cpu topology 55 * detection. 56 */ 57 int detect_extended_topology(struct cpuinfo_x86 *c) 58 { 59 #ifdef CONFIG_SMP 60 unsigned int eax, ebx, ecx, edx, sub_index; 61 unsigned int ht_mask_width, core_plus_mask_width; 62 unsigned int core_select_mask, core_level_siblings; 63 64 if (detect_extended_topology_early(c) < 0) 65 return -1; 66 67 /* 68 * Populate HT related information from sub-leaf level 0. 69 */ 70 cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx); 71 core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx); 72 core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); 73 74 sub_index = 1; 75 do { 76 cpuid_count(0xb, sub_index, &eax, &ebx, &ecx, &edx); 77 78 /* 79 * Check for the Core type in the implemented sub leaves. 80 */ 81 if (LEAFB_SUBTYPE(ecx) == CORE_TYPE) { 82 core_level_siblings = LEVEL_MAX_SIBLINGS(ebx); 83 core_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); 84 break; 85 } 86 87 sub_index++; 88 } while (LEAFB_SUBTYPE(ecx) != INVALID_TYPE); 89 90 core_select_mask = (~(-1 << core_plus_mask_width)) >> ht_mask_width; 91 92 c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, ht_mask_width) 93 & core_select_mask; 94 c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, core_plus_mask_width); 95 /* 96 * Reinit the apicid, now that we have extended initial_apicid. 97 */ 98 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0); 99 100 c->x86_max_cores = (core_level_siblings / smp_num_siblings); 101 #endif 102 return 0; 103 } 104