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