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 #include "cpu.h" 14 15 /* leaf 0xb SMT level */ 16 #define SMT_LEVEL 0 17 18 /* leaf 0xb sub-leaf types */ 19 #define INVALID_TYPE 0 20 #define SMT_TYPE 1 21 #define CORE_TYPE 2 22 23 #define LEAFB_SUBTYPE(ecx) (((ecx) >> 8) & 0xff) 24 #define BITS_SHIFT_NEXT_LEVEL(eax) ((eax) & 0x1f) 25 #define LEVEL_MAX_SIBLINGS(ebx) ((ebx) & 0xffff) 26 27 int detect_extended_topology_early(struct cpuinfo_x86 *c) 28 { 29 #ifdef CONFIG_SMP 30 unsigned int eax, ebx, ecx, edx; 31 32 if (c->cpuid_level < 0xb) 33 return -1; 34 35 cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx); 36 37 /* 38 * check if the cpuid leaf 0xb is actually implemented. 39 */ 40 if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE)) 41 return -1; 42 43 set_cpu_cap(c, X86_FEATURE_XTOPOLOGY); 44 45 /* 46 * initial apic id, which also represents 32-bit extended x2apic id. 47 */ 48 c->initial_apicid = edx; 49 smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx); 50 #endif 51 return 0; 52 } 53 54 /* 55 * Check for extended topology enumeration cpuid leaf 0xb and if it 56 * exists, use it for populating initial_apicid and cpu topology 57 * detection. 58 */ 59 int detect_extended_topology(struct cpuinfo_x86 *c) 60 { 61 #ifdef CONFIG_SMP 62 unsigned int eax, ebx, ecx, edx, sub_index; 63 unsigned int ht_mask_width, core_plus_mask_width; 64 unsigned int core_select_mask, core_level_siblings; 65 66 if (detect_extended_topology_early(c) < 0) 67 return -1; 68 69 /* 70 * Populate HT related information from sub-leaf level 0. 71 */ 72 cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx); 73 core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx); 74 core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); 75 76 sub_index = 1; 77 do { 78 cpuid_count(0xb, sub_index, &eax, &ebx, &ecx, &edx); 79 80 /* 81 * Check for the Core type in the implemented sub leaves. 82 */ 83 if (LEAFB_SUBTYPE(ecx) == CORE_TYPE) { 84 core_level_siblings = LEVEL_MAX_SIBLINGS(ebx); 85 core_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); 86 break; 87 } 88 89 sub_index++; 90 } while (LEAFB_SUBTYPE(ecx) != INVALID_TYPE); 91 92 core_select_mask = (~(-1 << core_plus_mask_width)) >> ht_mask_width; 93 94 c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, ht_mask_width) 95 & core_select_mask; 96 c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, core_plus_mask_width); 97 /* 98 * Reinit the apicid, now that we have extended initial_apicid. 99 */ 100 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0); 101 102 c->x86_max_cores = (core_level_siblings / smp_num_siblings); 103 #endif 104 return 0; 105 } 106