src/cpu/x86/topology.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <cpu/cpu.h>
   4 #include <device/device.h>
   5 #include <cpu/x86/topology.h>
   6
   7 #define CPUID_EXTENDED_CPU_TOPOLOGY 0x0b
   8 #define LEVEL_TYPE_CORE 2
   9 #define LEVEL_TYPE_SMT 1
  10
  11 #define CPUID_CPU_TOPOLOGY(x, val) \
  12         (((val) >> CPUID_CPU_TOPOLOGY_##x##_SHIFT) & CPUID_CPU_TOPOLOGY_##x##_MASK)
  13
  14 #define CPUID_CPU_TOPOLOGY_LEVEL_TYPE_SHIFT 0x8
  15 #define CPUID_CPU_TOPOLOGY_LEVEL_TYPE_MASK 0xff
  16 #define CPUID_CPU_TOPOLOGY_LEVEL(res) CPUID_CPU_TOPOLOGY(LEVEL_TYPE, (res).ecx)
  17
  18 #define CPUID_CPU_TOPOLOGY_LEVEL_BITS_SHIFT 0x0
  19 #define CPUID_CPU_TOPOLOGY_LEVEL_BITS_MASK 0x1f
  20 #define CPUID_CPU_TOPOLOGY_THREAD_BITS(res) CPUID_CPU_TOPOLOGY(LEVEL_BITS, (res).eax)
  21 #define CPUID_CPU_TOPOLOGY_CORE_BITS(res, threadbits) \
  22         ((CPUID_CPU_TOPOLOGY(LEVEL_BITS, (res).eax)) - threadbits)
  23
  24 /* Get number of bits for core ID and SMT ID */
  25 static enum cb_err get_cpu_core_thread_bits(uint32_t *core_bits, uint32_t *thread_bits)
  26 {
  27         struct cpuid_result cpuid_regs;
  28         int level_num, cpu_id_op = 0;
  29         const uint32_t cpuid_max_func = cpuid_get_max_func();
  30
  31         /*
  32          * Not all CPUs support this, those won't get topology filled in here.
  33          * CPU specific code can do this however.
  34          */
  35         if (cpuid_max_func < CPUID_EXTENDED_CPU_TOPOLOGY)
  36                 return CB_ERR;
  37
  38         cpu_id_op = CPUID_EXTENDED_CPU_TOPOLOGY;
  39
  40         *core_bits = level_num = 0;
  41         cpuid_regs = cpuid_ext(cpu_id_op, level_num);
  42
  43         /*
  44          * Sub-leaf index 0 enumerates SMT level, some AMD CPUs leave this CPUID leaf
  45          * reserved so bail out. Cpu specific code can fill in the topology later.
  46          */
  47         if (CPUID_CPU_TOPOLOGY_LEVEL(cpuid_regs) != LEVEL_TYPE_SMT)
  48                 return CB_ERR;
  49
  50         *thread_bits = CPUID_CPU_TOPOLOGY_THREAD_BITS(cpuid_regs);
  51         do {
  52                 level_num++;
  53                 cpuid_regs = cpuid_ext(cpu_id_op, level_num);
  54                 if (CPUID_CPU_TOPOLOGY_LEVEL(cpuid_regs) == LEVEL_TYPE_CORE) {
  55                         *core_bits = CPUID_CPU_TOPOLOGY_CORE_BITS(cpuid_regs, *thread_bits);
  56                         break;
  57                 }
  58         /* Stop when level type is invalid i.e 0 */
  59         } while (CPUID_CPU_TOPOLOGY_LEVEL(cpuid_regs));
  60
  61         return CB_SUCCESS;
  62 }
  63
  64 static void set_cpu_topology(struct device *cpu, unsigned int node,
  65                       unsigned int package, unsigned int core,
  66                       unsigned int thread)
  67 {
  68         cpu->path.apic.node_id = node;
  69         cpu->path.apic.package_id = package;
  70         cpu->path.apic.core_id = core;
  71         cpu->path.apic.thread_id = thread;
  72 }
  73
  74 void set_cpu_topology_from_leaf_b(struct device *cpu)
  75 {
  76         static uint32_t core_bits, thread_bits;
  77         static enum cb_err core_thread_bits_ret;
  78         static bool done = false;
  79         if (!done) {
  80                 core_thread_bits_ret = get_cpu_core_thread_bits(&core_bits, &thread_bits);
  81                 done = true;
  82         }
  83
  84         const uint32_t apicid = cpu->path.apic.initial_lapicid;
  85         uint32_t package_id, core_id, thread_id;
  86         /*
  87          *  If leaf_b does not exist set the following best-guess defaults:
  88          * - 1 package
  89          * - no SMP
  90          * - core_id = apicid
  91          * CPU specific code can always update these later on.
  92          */
  93         if (core_thread_bits_ret != CB_SUCCESS) {
  94                 package_id = 0;
  95                 core_id = apicid;
  96                 thread_id = 0;
  97         } else {
  98                 package_id = apicid >> (thread_bits + core_bits);
  99                 core_id = (apicid >> thread_bits) & ((1 << core_bits) - 1);
 100                 thread_id = apicid & ((1 << thread_bits) - 1);
 101         }
 102
 103         set_cpu_topology(cpu, 0, package_id, core_id, thread_id);
 104 }