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129 lines
2.9 KiB
129 lines
2.9 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/types.h> |
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#include "bitops.h" |
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#include <asm/processor-flags.h> |
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#include <asm/required-features.h> |
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#include <asm/msr-index.h> |
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#include "cpuflags.h" |
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struct cpu_features cpu; |
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u32 cpu_vendor[3]; |
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static bool loaded_flags; |
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static int has_fpu(void) |
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{ |
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u16 fcw = -1, fsw = -1; |
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unsigned long cr0; |
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asm volatile("mov %%cr0,%0" : "=r" (cr0)); |
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if (cr0 & (X86_CR0_EM|X86_CR0_TS)) { |
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cr0 &= ~(X86_CR0_EM|X86_CR0_TS); |
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asm volatile("mov %0,%%cr0" : : "r" (cr0)); |
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} |
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asm volatile("fninit ; fnstsw %0 ; fnstcw %1" |
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: "+m" (fsw), "+m" (fcw)); |
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return fsw == 0 && (fcw & 0x103f) == 0x003f; |
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} |
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/* |
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* For building the 16-bit code we want to explicitly specify 32-bit |
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* push/pop operations, rather than just saying 'pushf' or 'popf' and |
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* letting the compiler choose. But this is also included from the |
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* compressed/ directory where it may be 64-bit code, and thus needs |
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* to be 'pushfq' or 'popfq' in that case. |
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*/ |
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#ifdef __x86_64__ |
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#define PUSHF "pushfq" |
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#define POPF "popfq" |
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#else |
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#define PUSHF "pushfl" |
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#define POPF "popfl" |
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#endif |
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int has_eflag(unsigned long mask) |
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{ |
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unsigned long f0, f1; |
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asm volatile(PUSHF " \n\t" |
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PUSHF " \n\t" |
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"pop %0 \n\t" |
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"mov %0,%1 \n\t" |
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"xor %2,%1 \n\t" |
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"push %1 \n\t" |
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POPF " \n\t" |
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PUSHF " \n\t" |
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"pop %1 \n\t" |
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POPF |
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: "=&r" (f0), "=&r" (f1) |
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: "ri" (mask)); |
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return !!((f0^f1) & mask); |
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} |
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/* Handle x86_32 PIC using ebx. */ |
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#if defined(__i386__) && defined(__PIC__) |
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# define EBX_REG "=r" |
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#else |
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# define EBX_REG "=b" |
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#endif |
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static inline void cpuid_count(u32 id, u32 count, |
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u32 *a, u32 *b, u32 *c, u32 *d) |
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{ |
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asm volatile(".ifnc %%ebx,%3 ; movl %%ebx,%3 ; .endif \n\t" |
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"cpuid \n\t" |
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".ifnc %%ebx,%3 ; xchgl %%ebx,%3 ; .endif \n\t" |
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: "=a" (*a), "=c" (*c), "=d" (*d), EBX_REG (*b) |
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: "a" (id), "c" (count) |
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); |
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} |
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#define cpuid(id, a, b, c, d) cpuid_count(id, 0, a, b, c, d) |
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void get_cpuflags(void) |
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{ |
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u32 max_intel_level, max_amd_level; |
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u32 tfms; |
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u32 ignored; |
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if (loaded_flags) |
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return; |
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loaded_flags = true; |
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if (has_fpu()) |
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set_bit(X86_FEATURE_FPU, cpu.flags); |
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if (has_eflag(X86_EFLAGS_ID)) { |
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cpuid(0x0, &max_intel_level, &cpu_vendor[0], &cpu_vendor[2], |
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&cpu_vendor[1]); |
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if (max_intel_level >= 0x00000001 && |
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max_intel_level <= 0x0000ffff) { |
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cpuid(0x1, &tfms, &ignored, &cpu.flags[4], |
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&cpu.flags[0]); |
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cpu.level = (tfms >> 8) & 15; |
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cpu.family = cpu.level; |
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cpu.model = (tfms >> 4) & 15; |
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if (cpu.level >= 6) |
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cpu.model += ((tfms >> 16) & 0xf) << 4; |
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} |
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if (max_intel_level >= 0x00000007) { |
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cpuid_count(0x00000007, 0, &ignored, &ignored, |
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&cpu.flags[16], &ignored); |
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} |
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cpuid(0x80000000, &max_amd_level, &ignored, &ignored, |
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&ignored); |
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if (max_amd_level >= 0x80000001 && |
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max_amd_level <= 0x8000ffff) { |
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cpuid(0x80000001, &ignored, &ignored, &cpu.flags[6], |
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&cpu.flags[1]); |
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} |
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} |
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}
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