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 */ 29 void 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 pr_info("CPU: Physical Processor ID: %d\n", 91 c->phys_proc_id); 92 if (c->x86_max_cores > 1) 93 pr_info("CPU: Processor Core ID: %d\n", 94 c->cpu_core_id); 95 printed = 1; 96 } 97 return; 98 #endif 99 } 100