diff options
Diffstat (limited to 'gpxe/src/arch/i386/core/cpu.c')
-rw-r--r-- | gpxe/src/arch/i386/core/cpu.c | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/gpxe/src/arch/i386/core/cpu.c b/gpxe/src/arch/i386/core/cpu.c new file mode 100644 index 00000000..c24fa4e6 --- /dev/null +++ b/gpxe/src/arch/i386/core/cpu.c @@ -0,0 +1,73 @@ +#include <stdint.h> +#include <string.h> +#include <cpu.h> + +/** @file + * + * CPU identification + * + */ + +/** + * Test to see if CPU flag is changeable + * + * @v flag Flag to test + * @ret can_change Flag is changeable + */ +static inline int flag_is_changeable ( unsigned int flag ) { + uint32_t f1, f2; + + __asm__ ( "pushfl\n\t" + "pushfl\n\t" + "popl %0\n\t" + "movl %0,%1\n\t" + "xorl %2,%0\n\t" + "pushl %0\n\t" + "popfl\n\t" + "pushfl\n\t" + "popl %0\n\t" + "popfl\n\t" + : "=&r" ( f1 ), "=&r" ( f2 ) + : "ir" ( flag ) ); + + return ( ( ( f1 ^ f2 ) & flag ) != 0 ); +} + +/** + * Get CPU information + * + * @v cpu CPU information structure to fill in + */ +void get_cpuinfo ( struct cpuinfo_x86 *cpu ) { + unsigned int cpuid_level; + unsigned int cpuid_extlevel; + unsigned int discard_1, discard_2, discard_3; + + memset ( cpu, 0, sizeof ( *cpu ) ); + + /* Check for CPUID instruction */ + if ( ! flag_is_changeable ( X86_EFLAGS_ID ) ) { + DBG ( "CPUID not supported\n" ); + return; + } + + /* Get features, if present */ + cpuid ( 0x00000000, &cpuid_level, &discard_1, + &discard_2, &discard_3 ); + if ( cpuid_level >= 0x00000001 ) { + cpuid ( 0x00000001, &discard_1, &discard_2, + &discard_3, &cpu->features ); + } else { + DBG ( "CPUID cannot return capabilities\n" ); + } + + /* Get 64-bit features, if present */ + cpuid ( 0x80000000, &cpuid_extlevel, &discard_1, + &discard_2, &discard_3 ); + if ( ( cpuid_extlevel & 0xffff0000 ) == 0x80000000 ) { + if ( cpuid_extlevel >= 0x80000001 ) { + cpuid ( 0x80000001, &discard_1, &discard_2, + &discard_3, &cpu->amd_features ); + } + } +} |