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 /* 32 * For building the 16-bit code we want to explicitly specify 32-bit 33 * push/pop operations, rather than just saying 'pushf' or 'popf' and 34 * letting the compiler choose. But this is also included from the 35 * compressed/ directory where it may be 64-bit code, and thus needs 36 * to be 'pushfq' or 'popfq' in that case. 37 */ 38 #ifdef __x86_64__ 39 #define PUSHF "pushfq" 40 #define POPF "popfq" 41 #else 42 #define PUSHF "pushfl" 43 #define POPF "popfl" 44 #endif 45 46 int has_eflag(unsigned long mask) 47 { 48 unsigned long f0, f1; 49 50 asm volatile(PUSHF " \n\t" 51 PUSHF " \n\t" 52 "pop %0 \n\t" 53 "mov %0,%1 \n\t" 54 "xor %2,%1 \n\t" 55 "push %1 \n\t" 56 POPF " \n\t" 57 PUSHF " \n\t" 58 "pop %1 \n\t" 59 POPF 60 : "=&r" (f0), "=&r" (f1) 61 : "ri" (mask)); 62 63 return !!((f0^f1) & mask); 64 } 65 66 /* Handle x86_32 PIC using ebx. */ 67 #if defined(__i386__) && defined(__PIC__) 68 # define EBX_REG "=r" 69 #else 70 # define EBX_REG "=b" 71 #endif 72 73 static inline void cpuid(u32 id, u32 *a, u32 *b, u32 *c, u32 *d) 74 { 75 asm volatile(".ifnc %%ebx,%3 ; movl %%ebx,%3 ; .endif \n\t" 76 "cpuid \n\t" 77 ".ifnc %%ebx,%3 ; xchgl %%ebx,%3 ; .endif \n\t" 78 : "=a" (*a), "=c" (*c), "=d" (*d), EBX_REG (*b) 79 : "a" (id) 80 ); 81 } 82 83 void get_cpuflags(void) 84 { 85 u32 max_intel_level, max_amd_level; 86 u32 tfms; 87 u32 ignored; 88 89 if (loaded_flags) 90 return; 91 loaded_flags = true; 92 93 if (has_fpu()) 94 set_bit(X86_FEATURE_FPU, cpu.flags); 95 96 if (has_eflag(X86_EFLAGS_ID)) { 97 cpuid(0x0, &max_intel_level, &cpu_vendor[0], &cpu_vendor[2], 98 &cpu_vendor[1]); 99 100 if (max_intel_level >= 0x00000001 && 101 max_intel_level <= 0x0000ffff) { 102 cpuid(0x1, &tfms, &ignored, &cpu.flags[4], 103 &cpu.flags[0]); 104 cpu.level = (tfms >> 8) & 15; 105 cpu.model = (tfms >> 4) & 15; 106 if (cpu.level >= 6) 107 cpu.model += ((tfms >> 16) & 0xf) << 4; 108 } 109 110 cpuid(0x80000000, &max_amd_level, &ignored, &ignored, 111 &ignored); 112 113 if (max_amd_level >= 0x80000001 && 114 max_amd_level <= 0x8000ffff) { 115 cpuid(0x80000001, &ignored, &ignored, &cpu.flags[6], 116 &cpu.flags[1]); 117 } 118 } 119 } 120