arch/x86/kernel/cpu/scattered.c

   1 /*
   2  *      Routines to identify additional cpu features that are scattered in
   3  *      cpuid space.
   4  */
   5 #include <linux/cpu.h>
   6
   7 #include <asm/pat.h>
   8 #include <asm/processor.h>
   9
  10 #include <asm/apic.h>
  11
  12 struct cpuid_bit {
  13         u16 feature;
  14         u8 reg;
  15         u8 bit;
  16         u32 level;
  17         u32 sub_leaf;
  18 };
  19
  20 /* Please keep the leaf sorted by cpuid_bit.level for faster search. */
  21 static const struct cpuid_bit cpuid_bits[] = {
  22         { X86_FEATURE_APERFMPERF,       CPUID_ECX,  0, 0x00000006, 0 },
  23         { X86_FEATURE_EPB,              CPUID_ECX,  3, 0x00000006, 0 },
  24         { X86_FEATURE_CAT_L3,           CPUID_EBX,  1, 0x00000010, 0 },
  25         { X86_FEATURE_CAT_L2,           CPUID_EBX,  2, 0x00000010, 0 },
  26         { X86_FEATURE_CDP_L3,           CPUID_ECX,  2, 0x00000010, 1 },
  27         { X86_FEATURE_MBA,              CPUID_EBX,  3, 0x00000010, 0 },
  28         { X86_FEATURE_HW_PSTATE,        CPUID_EDX,  7, 0x80000007, 0 },
  29         { X86_FEATURE_CPB,              CPUID_EDX,  9, 0x80000007, 0 },
  30         { X86_FEATURE_PROC_FEEDBACK,    CPUID_EDX, 11, 0x80000007, 0 },
  31         { X86_FEATURE_SME,              CPUID_EAX,  0, 0x8000001f, 0 },
  32         { 0, 0, 0, 0, 0 }
  33 };
  34
  35 void init_scattered_cpuid_features(struct cpuinfo_x86 *c)
  36 {
  37         u32 max_level;
  38         u32 regs[4];
  39         const struct cpuid_bit *cb;
  40
  41         for (cb = cpuid_bits; cb->feature; cb++) {
  42
  43                 /* Verify that the level is valid */
  44                 max_level = cpuid_eax(cb->level & 0xffff0000);
  45                 if (max_level < cb->level ||
  46                     max_level > (cb->level | 0xffff))
  47                         continue;
  48
  49                 cpuid_count(cb->level, cb->sub_leaf, &regs[CPUID_EAX],
  50                             &regs[CPUID_EBX], &regs[CPUID_ECX],
  51                             &regs[CPUID_EDX]);
  52
  53                 if (regs[cb->reg] & (1 << cb->bit))
  54                         set_cpu_cap(c, cb->feature);
  55         }
  56 }
  57
  58 u32 get_scattered_cpuid_leaf(unsigned int level, unsigned int sub_leaf,
  59                              enum cpuid_regs_idx reg)
  60 {
  61         const struct cpuid_bit *cb;
  62         u32 cpuid_val = 0;
  63
  64         for (cb = cpuid_bits; cb->feature; cb++) {
  65
  66                 if (level > cb->level)
  67                         continue;
  68
  69                 if (level < cb->level)
  70                         break;
  71
  72                 if (reg == cb->reg && sub_leaf == cb->sub_leaf) {
  73                         if (cpu_has(&boot_cpu_data, cb->feature))
  74                                 cpuid_val |= BIT(cb->bit);
  75                 }
  76         }
  77
  78         return cpuid_val;
  79 }
  80 EXPORT_SYMBOL_GPL(get_scattered_cpuid_leaf);