arch/x86/kernel/cpu/addon_cpuid_features.c

   1
   2 /*
   3  *      Routines to indentify additional cpu features that are scattered in
   4  *      cpuid space.
   5  */
   6
   7 #include <linux/cpu.h>
   8
   9 #include <asm/pat.h>
  10 #include <asm/processor.h>
  11
  12 struct cpuid_bit {
  13         u16 feature;
  14         u8 reg;
  15         u8 bit;
  16         u32 level;
  17 };
  18
  19 enum cpuid_regs {
  20         CR_EAX = 0,
  21         CR_ECX,
  22         CR_EDX,
  23         CR_EBX
  24 };
  25
  26 void __cpuinit init_scattered_cpuid_features(struct cpuinfo_x86 *c)
  27 {
  28         u32 max_level;
  29         u32 regs[4];
  30         const struct cpuid_bit *cb;
  31
  32         static const struct cpuid_bit cpuid_bits[] = {
  33                 { X86_FEATURE_IDA, CR_EAX, 1, 0x00000006 },
  34                 { 0, 0, 0, 0 }
  35         };
  36
  37         for (cb = cpuid_bits; cb->feature; cb++) {
  38
  39                 /* Verify that the level is valid */
  40                 max_level = cpuid_eax(cb->level & 0xffff0000);
  41                 if (max_level < cb->level ||
  42                     max_level > (cb->level | 0xffff))
  43                         continue;
  44
  45                 cpuid(cb->level, &regs[CR_EAX], &regs[CR_EBX],
  46                         &regs[CR_ECX], &regs[CR_EDX]);
  47
  48                 if (regs[cb->reg] & (1 << cb->bit))
  49                         set_cpu_cap(c, cb->feature);
  50         }
  51 }
  52
  53 #ifdef CONFIG_X86_PAT
  54 void __cpuinit validate_pat_support(struct cpuinfo_x86 *c)
  55 {
  56         if (!cpu_has_pat)
  57                 pat_disable("PAT not supported by CPU.");
  58
  59         switch (c->x86_vendor) {
  60         case X86_VENDOR_INTEL:
  61                 if (c->x86 == 0xF || (c->x86 == 6 && c->x86_model >= 15))
  62                         return;
  63                 break;
  64         case X86_VENDOR_AMD:
  65         case X86_VENDOR_CENTAUR:
  66         case X86_VENDOR_TRANSMETA:
  67                 return;
  68         }
  69
  70         pat_disable("PAT disabled. Not yet verified on this CPU type.");
  71 }
  72 #endif