1 #include <stdint.h>
2 #include <string.h>
3 #include <cpu.h>
4
5 /** @file
6 *
7 * CPU identification
8 *
9 */
10
11 /**
12 * Test to see if CPU flag is changeable
13 *
14 * @v flag Flag to test
15 * @ret can_change Flag is changeable
16 */
flag_is_changeable(unsigned int flag)17 static inline int flag_is_changeable ( unsigned int flag ) {
18 uint32_t f1, f2;
19
20 __asm__ ( "pushfl\n\t"
21 "pushfl\n\t"
22 "popl %0\n\t"
23 "movl %0,%1\n\t"
24 "xorl %2,%0\n\t"
25 "pushl %0\n\t"
26 "popfl\n\t"
27 "pushfl\n\t"
28 "popl %0\n\t"
29 "popfl\n\t"
30 : "=&r" ( f1 ), "=&r" ( f2 )
31 : "ir" ( flag ) );
32
33 return ( ( ( f1 ^ f2 ) & flag ) != 0 );
34 }
35
36 /**
37 * Get CPU information
38 *
39 * @v cpu CPU information structure to fill in
40 */
get_cpuinfo(struct cpuinfo_x86 * cpu)41 void get_cpuinfo ( struct cpuinfo_x86 *cpu ) {
42 unsigned int cpuid_level;
43 unsigned int cpuid_extlevel;
44 unsigned int discard_1, discard_2, discard_3;
45
46 memset ( cpu, 0, sizeof ( *cpu ) );
47
48 /* Check for CPUID instruction */
49 if ( ! flag_is_changeable ( X86_EFLAGS_ID ) ) {
50 DBG ( "CPUID not supported\n" );
51 return;
52 }
53
54 /* Get features, if present */
55 cpuid ( 0x00000000, &cpuid_level, &discard_1,
56 &discard_2, &discard_3 );
57 if ( cpuid_level >= 0x00000001 ) {
58 cpuid ( 0x00000001, &discard_1, &discard_2,
59 &discard_3, &cpu->features );
60 } else {
61 DBG ( "CPUID cannot return capabilities\n" );
62 }
63
64 /* Get 64-bit features, if present */
65 cpuid ( 0x80000000, &cpuid_extlevel, &discard_1,
66 &discard_2, &discard_3 );
67 if ( ( cpuid_extlevel & 0xffff0000 ) == 0x80000000 ) {
68 if ( cpuid_extlevel >= 0x80000001 ) {
69 cpuid ( 0x80000001, &discard_1, &discard_2,
70 &discard_3, &cpu->amd_features );
71 }
72 }
73 }
74