arch/x86/kernel/cpu/topology_ext.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/cpu.h>
   3
   4 #include <asm/apic.h>
   5 #include <asm/memtype.h>
   6 #include <asm/processor.h>
   7
   8 #include "cpu.h"
   9
  10 enum topo_types {
  11         INVALID_TYPE            = 0,
  12         SMT_TYPE                = 1,
  13         CORE_TYPE               = 2,
  14         MAX_TYPE_0B             = 3,
  15         MODULE_TYPE             = 3,
  16         AMD_CCD_TYPE            = 3,
  17         TILE_TYPE               = 4,
  18         AMD_SOCKET_TYPE         = 4,
  19         MAX_TYPE_80000026       = 5,
  20         DIE_TYPE                = 5,
  21         DIEGRP_TYPE             = 6,
  22         MAX_TYPE_1F             = 7,
  23 };
  24
  25 /*
  26  * Use a lookup table for the case that there are future types > 6 which
  27  * describe an intermediate domain level which does not exist today.
  28  */
  29 static const unsigned int topo_domain_map_0b_1f[MAX_TYPE_1F] = {
  30         [SMT_TYPE]      = TOPO_SMT_DOMAIN,
  31         [CORE_TYPE]     = TOPO_CORE_DOMAIN,
  32         [MODULE_TYPE]   = TOPO_MODULE_DOMAIN,
  33         [TILE_TYPE]     = TOPO_TILE_DOMAIN,
  34         [DIE_TYPE]      = TOPO_DIE_DOMAIN,
  35         [DIEGRP_TYPE]   = TOPO_DIEGRP_DOMAIN,
  36 };
  37
  38 static const unsigned int topo_domain_map_80000026[MAX_TYPE_80000026] = {
  39         [SMT_TYPE]              = TOPO_SMT_DOMAIN,
  40         [CORE_TYPE]             = TOPO_CORE_DOMAIN,
  41         [AMD_CCD_TYPE]          = TOPO_TILE_DOMAIN,
  42         [AMD_SOCKET_TYPE]       = TOPO_DIE_DOMAIN,
  43 };
  44
  45 static inline bool topo_subleaf(struct topo_scan *tscan, u32 leaf, u32 subleaf,
  46                                 unsigned int *last_dom)
  47 {
  48         unsigned int dom, maxtype;
  49         const unsigned int *map;
  50         struct {
  51                 // eax
  52                 u32     x2apic_shift    :  5, // Number of bits to shift APIC ID right
  53                                               // for the topology ID at the next level
  54                                         : 27; // Reserved
  55                 // ebx
  56                 u32     num_processors  : 16, // Number of processors at current level
  57                                         : 16; // Reserved
  58                 // ecx
  59                 u32     level           :  8, // Current topology level. Same as sub leaf number
  60                         type            :  8, // Level type. If 0, invalid
  61                                         : 16; // Reserved
  62                 // edx
  63                 u32     x2apic_id       : 32; // X2APIC ID of the current logical processor
  64         } sl;
  65
  66         switch (leaf) {
  67         case 0x0b: maxtype = MAX_TYPE_0B; map = topo_domain_map_0b_1f; break;
  68         case 0x1f: maxtype = MAX_TYPE_1F; map = topo_domain_map_0b_1f; break;
  69         case 0x80000026: maxtype = MAX_TYPE_80000026; map = topo_domain_map_80000026; break;
  70         default: return false;
  71         }
  72
  73         cpuid_subleaf(leaf, subleaf, &sl);
  74
  75         if (!sl.num_processors || sl.type == INVALID_TYPE)
  76                 return false;
  77
  78         if (sl.type >= maxtype) {
  79                 pr_err_once("Topology: leaf 0x%x:%d Unknown domain type %u\n",
  80                             leaf, subleaf, sl.type);
  81                 /*
  82                  * It really would have been too obvious to make the domain
  83                  * type space sparse and leave a few reserved types between
  84                  * the points which might change instead of following the
  85                  * usual "this can be fixed in software" principle.
  86                  */
  87                 dom = *last_dom + 1;
  88         } else {
  89                 dom = map[sl.type];
  90                 *last_dom = dom;
  91         }
  92
  93         if (!dom) {
  94                 tscan->c->topo.initial_apicid = sl.x2apic_id;
  95         } else if (tscan->c->topo.initial_apicid != sl.x2apic_id) {
  96                 pr_warn_once(FW_BUG "CPUID leaf 0x%x subleaf %d APIC ID mismatch %x != %x\n",
  97                              leaf, subleaf, tscan->c->topo.initial_apicid, sl.x2apic_id);
  98         }
  99
 100         topology_set_dom(tscan, dom, sl.x2apic_shift, sl.num_processors);
 101         return true;
 102 }
 103
 104 static bool parse_topology_leaf(struct topo_scan *tscan, u32 leaf)
 105 {
 106         unsigned int last_dom;
 107         u32 subleaf;
 108
 109         /* Read all available subleafs and populate the levels */
 110         for (subleaf = 0, last_dom = 0; topo_subleaf(tscan, leaf, subleaf, &last_dom); subleaf++);
 111
 112         /* If subleaf 0 failed to parse, give up */
 113         if (!subleaf)
 114                 return false;
 115
 116         /*
 117          * There are machines in the wild which have shift 0 in the subleaf
 118          * 0, but advertise 2 logical processors at that level. They are
 119          * truly SMT.
 120          */
 121         if (!tscan->dom_shifts[TOPO_SMT_DOMAIN] && tscan->dom_ncpus[TOPO_SMT_DOMAIN] > 1) {
 122                 unsigned int sft = get_count_order(tscan->dom_ncpus[TOPO_SMT_DOMAIN]);
 123
 124                 pr_warn_once(FW_BUG "CPUID leaf 0x%x subleaf 0 has shift level 0 but %u CPUs. Fixing it up.\n",
 125                              leaf, tscan->dom_ncpus[TOPO_SMT_DOMAIN]);
 126                 topology_update_dom(tscan, TOPO_SMT_DOMAIN, sft, tscan->dom_ncpus[TOPO_SMT_DOMAIN]);
 127         }
 128
 129         set_cpu_cap(tscan->c, X86_FEATURE_XTOPOLOGY);
 130         return true;
 131 }
 132
 133 bool cpu_parse_topology_ext(struct topo_scan *tscan)
 134 {
 135         /* Intel: Try leaf 0x1F first. */
 136         if (tscan->c->cpuid_level >= 0x1f && parse_topology_leaf(tscan, 0x1f))
 137                 return true;
 138
 139         /* AMD: Try leaf 0x80000026 first. */
 140         if (tscan->c->extended_cpuid_level >= 0x80000026 && parse_topology_leaf(tscan, 0x80000026))
 141                 return true;
 142
 143         /* Intel/AMD: Fall back to leaf 0xB if available */
 144         return tscan->c->cpuid_level >= 0x0b && parse_topology_leaf(tscan, 0x0b);
 145 }