LXR linux/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
  12struct cpuid_bit {
  13        u16 feature;
  14        u8 reg;
  15        u8 bit;
  16        u32 level;
  17        u32 sub_leaf;
  18};
  19
  20enum cpuid_regs {
  21        CR_EAX = 0,
  22        CR_ECX,
  23        CR_EDX,
  24        CR_EBX
  25};
  26
  27void init_scattered_cpuid_features(struct cpuinfo_x86 *c)
  28{
  29        u32 max_level;
  30        u32 regs[4];
  31        const struct cpuid_bit *cb;
  32
  33        static const struct cpuid_bit cpuid_bits[] = {
  34                { X86_FEATURE_INTEL_PT,         CR_EBX,25, 0x00000007, 0 },
  35                { X86_FEATURE_APERFMPERF,       CR_ECX, 0, 0x00000006, 0 },
  36                { X86_FEATURE_EPB,              CR_ECX, 3, 0x00000006, 0 },
  37                { X86_FEATURE_HW_PSTATE,        CR_EDX, 7, 0x80000007, 0 },
  38                { X86_FEATURE_CPB,              CR_EDX, 9, 0x80000007, 0 },
  39                { X86_FEATURE_PROC_FEEDBACK,    CR_EDX,11, 0x80000007, 0 },
  40                { 0, 0, 0, 0, 0 }
  41        };
  42
  43        for (cb = cpuid_bits; cb->feature; cb++) {
  44
  45                /* Verify that the level is valid */
  46                max_level = cpuid_eax(cb->level & 0xffff0000);
  47                if (max_level < cb->level ||
  48                    max_level > (cb->level | 0xffff))
  49                        continue;
  50
  51                cpuid_count(cb->level, cb->sub_leaf, &regs[CR_EAX],
  52                            &regs[CR_EBX], &regs[CR_ECX], &regs[CR_EDX]);
  53
  54                if (regs[cb->reg] & (1 << cb->bit))
  55                        set_cpu_cap(c, cb->feature);
  56        }
  57}
  58