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 enum cpuid_regs {
21 CR_EAX = 0,
22 CR_ECX,
23 CR_EDX,
24 CR_EBX
25 };
26
init_scattered_cpuid_features(struct cpuinfo_x86 * c)27 void 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_APERFMPERF, CR_ECX, 0, 0x00000006, 0 },
35 { X86_FEATURE_EPB, CR_ECX, 3, 0x00000006, 0 },
36 { X86_FEATURE_HW_PSTATE, CR_EDX, 7, 0x80000007, 0 },
37 { X86_FEATURE_CPB, CR_EDX, 9, 0x80000007, 0 },
38 { X86_FEATURE_PROC_FEEDBACK, CR_EDX,11, 0x80000007, 0 },
39 { 0, 0, 0, 0, 0 }
40 };
41
42 for (cb = cpuid_bits; cb->feature; cb++) {
43
44 /* Verify that the level is valid */
45 max_level = cpuid_eax(cb->level & 0xffff0000);
46 if (max_level < cb->level ||
47 max_level > (cb->level | 0xffff))
48 continue;
49
50 cpuid_count(cb->level, cb->sub_leaf, ®s[CR_EAX],
51 ®s[CR_EBX], ®s[CR_ECX], ®s[CR_EDX]);
52
53 if (regs[cb->reg] & (1 << cb->bit))
54 set_cpu_cap(c, cb->feature);
55 }
56 }
57