src/arch/x86/cpu_common.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <cpu/cpu.h>
   4
   5 #ifndef __x86_64__
   6 /* Standard macro to see if a specific flag is changeable */
   7 static inline int flag_is_changeable_p(uint32_t flag)
   8 {
   9         uint32_t f1, f2;
  10
  11         asm(
  12                 "pushfl\n\t"
  13                 "pushfl\n\t"
  14                 "popl %0\n\t"
  15                 "movl %0,%1\n\t"
  16                 "xorl %2,%0\n\t"
  17                 "pushl %0\n\t"
  18                 "popfl\n\t"
  19                 "pushfl\n\t"
  20                 "popl %0\n\t"
  21                 "popfl\n\t"
  22                 : "=&r" (f1), "=&r" (f2)
  23                 : "ir" (flag));
  24         return ((f1^f2) & flag) != 0;
  25 }
  26
  27 /* Probe for the CPUID instruction */
  28 int cpu_have_cpuid(void)
  29 {
  30         return flag_is_changeable_p(X86_EFLAGS_ID);
  31 }
  32
  33 #else
  34
  35 int cpu_have_cpuid(void)
  36 {
  37         return 1;
  38 }
  39 #endif
  40
  41 unsigned int cpu_cpuid_extended_level(void)
  42 {
  43         return cpuid_eax(0x80000000);
  44 }
  45
  46 int cpu_phys_address_size(void)
  47 {
  48         if (!(cpu_have_cpuid()))
  49                 return 32;
  50
  51         if (cpu_cpuid_extended_level() >= 0x80000008)
  52                 return cpuid_eax(0x80000008) & 0xff;
  53
  54         if (cpuid_edx(1) & (CPUID_FEATURE_PAE | CPUID_FEATURE_PSE36))
  55                 return 36;
  56         return 32;
  57 }
  58
  59 /*
  60  * Get processor id using cpuid eax=1
  61  * return value in EAX register
  62  */
  63 uint32_t cpu_get_cpuid(void)
  64 {
  65         return cpuid_eax(1);
  66 }
  67
  68 /*
  69  * Get processor feature flag using cpuid eax=1
  70  * return value in ECX register
  71  */
  72 uint32_t cpu_get_feature_flags_ecx(void)
  73 {
  74         return cpuid_ecx(1);
  75 }
  76
  77 /*
  78  * Get processor feature flag using cpuid eax=1
  79  * return value in EDX register
  80  */
  81 uint32_t cpu_get_feature_flags_edx(void)
  82 {
  83         return cpuid_edx(1);
  84 }