xref: /linux/arch/x86/kernel/cpu/scattered.c (revision c4ee0af3fa0dc65f690fc908f02b8355f9576ea0) 
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 
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_DTHERM,		CR_EAX, 0, 0x00000006, 0 },
35 		{ X86_FEATURE_IDA,		CR_EAX, 1, 0x00000006, 0 },
36 		{ X86_FEATURE_ARAT,		CR_EAX, 2, 0x00000006, 0 },
37 		{ X86_FEATURE_PLN,		CR_EAX, 4, 0x00000006, 0 },
38 		{ X86_FEATURE_PTS,		CR_EAX, 6, 0x00000006, 0 },
39 		{ X86_FEATURE_APERFMPERF,	CR_ECX, 0, 0x00000006, 0 },
40 		{ X86_FEATURE_EPB,		CR_ECX, 3, 0x00000006, 0 },
41 		{ X86_FEATURE_XSAVEOPT,		CR_EAX,	0, 0x0000000d, 1 },
42 		{ X86_FEATURE_HW_PSTATE,	CR_EDX, 7, 0x80000007, 0 },
43 		{ X86_FEATURE_CPB,		CR_EDX, 9, 0x80000007, 0 },
44 		{ X86_FEATURE_PROC_FEEDBACK,	CR_EDX,11, 0x80000007, 0 },
45 		{ X86_FEATURE_NPT,		CR_EDX, 0, 0x8000000a, 0 },
46 		{ X86_FEATURE_LBRV,		CR_EDX, 1, 0x8000000a, 0 },
47 		{ X86_FEATURE_SVML,		CR_EDX, 2, 0x8000000a, 0 },
48 		{ X86_FEATURE_NRIPS,		CR_EDX, 3, 0x8000000a, 0 },
49 		{ X86_FEATURE_TSCRATEMSR,	CR_EDX, 4, 0x8000000a, 0 },
50 		{ X86_FEATURE_VMCBCLEAN,	CR_EDX, 5, 0x8000000a, 0 },
51 		{ X86_FEATURE_FLUSHBYASID,	CR_EDX, 6, 0x8000000a, 0 },
52 		{ X86_FEATURE_DECODEASSISTS,	CR_EDX, 7, 0x8000000a, 0 },
53 		{ X86_FEATURE_PAUSEFILTER,	CR_EDX,10, 0x8000000a, 0 },
54 		{ X86_FEATURE_PFTHRESHOLD,	CR_EDX,12, 0x8000000a, 0 },
55 		{ 0, 0, 0, 0, 0 }
56 	};
57 
58 	for (cb = cpuid_bits; cb->feature; cb++) {
59 
60 		/* Verify that the level is valid */
61 		max_level = cpuid_eax(cb->level & 0xffff0000);
62 		if (max_level < cb->level ||
63 		    max_level > (cb->level | 0xffff))
64 			continue;
65 
66 		cpuid_count(cb->level, cb->sub_leaf, &regs[CR_EAX],
67 			    &regs[CR_EBX], &regs[CR_ECX], &regs[CR_EDX]);
68 
69 		if (regs[cb->reg] & (1 << cb->bit))
70 			set_cpu_cap(c, cb->feature);
71 	}
72 }
73