arch/x86/kernel/cpu/match.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <asm/cpu_device_id.h>
   3 #include <asm/cpufeature.h>
   4 #include <linux/cpu.h>
   5 #include <linux/export.h>
   6 #include <linux/slab.h>
   7
   8 /**
   9  * x86_match_cpu - match current CPU again an array of x86_cpu_ids
  10  * @match: Pointer to array of x86_cpu_ids. Last entry terminated with
  11  *         {}.
  12  *
  13  * Return the entry if the current CPU matches the entries in the
  14  * passed x86_cpu_id match table. Otherwise NULL.  The match table
  15  * contains vendor (X86_VENDOR_*), family, model and feature bits or
  16  * respective wildcard entries.
  17  *
  18  * A typical table entry would be to match a specific CPU
  19  * { X86_VENDOR_INTEL, 6, 0x12 }
  20  * or to match a specific CPU feature
  21  * { X86_FEATURE_MATCH(X86_FEATURE_FOOBAR) }
  22  *
  23  * Fields can be wildcarded with %X86_VENDOR_ANY, %X86_FAMILY_ANY,
  24  * %X86_MODEL_ANY, %X86_FEATURE_ANY or 0 (except for vendor)
  25  *
  26  * Arrays used to match for this should also be declared using
  27  * MODULE_DEVICE_TABLE(x86cpu, ...)
  28  *
  29  * This always matches against the boot cpu, assuming models and features are
  30  * consistent over all CPUs.
  31  */
  32 const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match)
  33 {
  34         const struct x86_cpu_id *m;
  35         struct cpuinfo_x86 *c = &boot_cpu_data;
  36
  37         for (m = match;
  38              m->vendor | m->family | m->model | m->steppings | m->feature;
  39              m++) {
  40                 if (m->vendor != X86_VENDOR_ANY && c->x86_vendor != m->vendor)
  41                         continue;
  42                 if (m->family != X86_FAMILY_ANY && c->x86 != m->family)
  43                         continue;
  44                 if (m->model != X86_MODEL_ANY && c->x86_model != m->model)
  45                         continue;
  46                 if (m->steppings != X86_STEPPING_ANY &&
  47                     !(BIT(c->x86_stepping) & m->steppings))
  48                         continue;
  49                 if (m->feature != X86_FEATURE_ANY && !cpu_has(c, m->feature))
  50                         continue;
  51                 return m;
  52         }
  53         return NULL;
  54 }
  55 EXPORT_SYMBOL(x86_match_cpu);