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[karo-tx-linux.git] / arch / x86 / boot / cpuflags.c
1 #include <linux/types.h>
2 #include "bitops.h"
3
4 #include <asm/processor-flags.h>
5 #include <asm/required-features.h>
6 #include <asm/msr-index.h>
7 #include "cpuflags.h"
8
9 struct cpu_features cpu;
10 u32 cpu_vendor[3];
11
12 static bool loaded_flags;
13
14 static int has_fpu(void)
15 {
16         u16 fcw = -1, fsw = -1;
17         unsigned long cr0;
18
19         asm volatile("mov %%cr0,%0" : "=r" (cr0));
20         if (cr0 & (X86_CR0_EM|X86_CR0_TS)) {
21                 cr0 &= ~(X86_CR0_EM|X86_CR0_TS);
22                 asm volatile("mov %0,%%cr0" : : "r" (cr0));
23         }
24
25         asm volatile("fninit ; fnstsw %0 ; fnstcw %1"
26                      : "+m" (fsw), "+m" (fcw));
27
28         return fsw == 0 && (fcw & 0x103f) == 0x003f;
29 }
30
31 int has_eflag(unsigned long mask)
32 {
33         unsigned long f0, f1;
34
35         asm volatile("pushf     \n\t"
36                      "pushf     \n\t"
37                      "pop %0    \n\t"
38                      "mov %0,%1 \n\t"
39                      "xor %2,%1 \n\t"
40                      "push %1   \n\t"
41                      "popf      \n\t"
42                      "pushf     \n\t"
43                      "pop %1    \n\t"
44                      "popf"
45                      : "=&r" (f0), "=&r" (f1)
46                      : "ri" (mask));
47
48         return !!((f0^f1) & mask);
49 }
50
51 /* Handle x86_32 PIC using ebx. */
52 #if defined(__i386__) && defined(__PIC__)
53 # define EBX_REG "=r"
54 #else
55 # define EBX_REG "=b"
56 #endif
57
58 static inline void cpuid(u32 id, u32 *a, u32 *b, u32 *c, u32 *d)
59 {
60         asm volatile(".ifnc %%ebx,%3 ; movl  %%ebx,%3 ; .endif  \n\t"
61                      "cpuid                                     \n\t"
62                      ".ifnc %%ebx,%3 ; xchgl %%ebx,%3 ; .endif  \n\t"
63                     : "=a" (*a), "=c" (*c), "=d" (*d), EBX_REG (*b)
64                     : "a" (id)
65         );
66 }
67
68 void get_cpuflags(void)
69 {
70         u32 max_intel_level, max_amd_level;
71         u32 tfms;
72         u32 ignored;
73
74         if (loaded_flags)
75                 return;
76         loaded_flags = true;
77
78         if (has_fpu())
79                 set_bit(X86_FEATURE_FPU, cpu.flags);
80
81         if (has_eflag(X86_EFLAGS_ID)) {
82                 cpuid(0x0, &max_intel_level, &cpu_vendor[0], &cpu_vendor[2],
83                       &cpu_vendor[1]);
84
85                 if (max_intel_level >= 0x00000001 &&
86                     max_intel_level <= 0x0000ffff) {
87                         cpuid(0x1, &tfms, &ignored, &cpu.flags[4],
88                               &cpu.flags[0]);
89                         cpu.level = (tfms >> 8) & 15;
90                         cpu.model = (tfms >> 4) & 15;
91                         if (cpu.level >= 6)
92                                 cpu.model += ((tfms >> 16) & 0xf) << 4;
93                 }
94
95                 cpuid(0x80000000, &max_amd_level, &ignored, &ignored,
96                       &ignored);
97
98                 if (max_amd_level >= 0x80000001 &&
99                     max_amd_level <= 0x8000ffff) {
100                         cpuid(0x80000001, &ignored, &ignored, &cpu.flags[6],
101                               &cpu.flags[1]);
102                 }
103         }
104 }