arch/all-pc/boot/grub2-aros/include/grub/i386/tsc.h

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 2008,2009  Free Software Foundation, Inc.
   4  *
   5  *  GRUB is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  GRUB is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #ifndef KERNEL_CPU_TSC_HEADER
  20 #define KERNEL_CPU_TSC_HEADER   1
  21
  22 #include <grub/types.h>
  23
  24 /* Read the TSC value, which increments with each CPU clock cycle. */
  25 static __inline grub_uint64_t
  26 grub_get_tsc (void)
  27 {
  28   grub_uint32_t lo, hi;
  29
  30   /* The CPUID instruction is a 'serializing' instruction, and
  31      avoids out-of-order execution of the RDTSC instruction. */
  32 #ifdef __APPLE__
  33   __asm__ __volatile__ ("xorl %%eax, %%eax\n\t"
  34 #ifdef __x86_64__
  35                         "push %%rbx\n"
  36 #else
  37                         "push %%ebx\n"
  38 #endif
  39                         "cpuid\n"
  40 #ifdef __x86_64__
  41                         "pop %%rbx\n"
  42 #else
  43                         "pop %%ebx\n"
  44 #endif
  45                         :::"%rax", "%rcx", "%rdx");
  46 #else
  47   __asm__ __volatile__ ("xorl %%eax, %%eax\n\t"
  48                         "cpuid":::"%rax", "%rbx", "%rcx", "%rdx");
  49 #endif
  50   /* Read TSC value.  We cannot use "=A", since this would use
  51      %rax on x86_64. */
  52   __asm__ __volatile__ ("rdtsc":"=a" (lo), "=d" (hi));
  53
  54   return (((grub_uint64_t) hi) << 32) | lo;
  55 }
  56
  57 #ifdef __x86_64__
  58
  59 static __inline int
  60 grub_cpu_is_cpuid_supported (void)
  61 {
  62   grub_uint64_t id_supported;
  63
  64   __asm__ ("pushfq\n\t"
  65            "popq %%rax             /* Get EFLAGS into EAX */\n\t"
  66            "movq %%rax, %%rcx      /* Save original flags in ECX */\n\t"
  67            "xorq $0x200000, %%rax  /* Flip ID bit in EFLAGS */\n\t"
  68            "pushq %%rax            /* Store modified EFLAGS on stack */\n\t"
  69            "popfq                  /* Replace current EFLAGS */\n\t"
  70            "pushfq                 /* Read back the EFLAGS */\n\t"
  71            "popq %%rax             /* Get EFLAGS into EAX */\n\t"
  72            "xorq %%rcx, %%rax      /* Check if flag could be modified */\n\t"
  73            : "=a" (id_supported)
  74            : /* No inputs.  */
  75            : /* Clobbered:  */ "%rcx");
  76
  77   return id_supported != 0;
  78 }
  79
  80 #else
  81
  82 static __inline int
  83 grub_cpu_is_cpuid_supported (void)
  84 {
  85   grub_uint32_t id_supported;
  86
  87   __asm__ ("pushfl\n\t"
  88            "popl %%eax             /* Get EFLAGS into EAX */\n\t"
  89            "movl %%eax, %%ecx      /* Save original flags in ECX */\n\t"
  90            "xorl $0x200000, %%eax  /* Flip ID bit in EFLAGS */\n\t"
  91            "pushl %%eax            /* Store modified EFLAGS on stack */\n\t"
  92            "popfl                  /* Replace current EFLAGS */\n\t"
  93            "pushfl                 /* Read back the EFLAGS */\n\t"
  94            "popl %%eax             /* Get EFLAGS into EAX */\n\t"
  95            "xorl %%ecx, %%eax      /* Check if flag could be modified */\n\t"
  96            : "=a" (id_supported)
  97            : /* No inputs.  */
  98            : /* Clobbered:  */ "%rcx");
  99
 100   return id_supported != 0;
 101 }
 102
 103 #endif
 104
 105 static __inline int
 106 grub_cpu_is_tsc_supported (void)
 107 {
 108   if (! grub_cpu_is_cpuid_supported ())
 109     return 0;
 110
 111   grub_uint32_t features;
 112 #ifdef __APPLE__
 113   __asm__ ("movl $1, %%eax\n\t"
 114 #ifdef __x86_64__
 115            "push %%rbx\n"
 116 #else
 117            "push %%ebx\n"
 118 #endif
 119            "cpuid\n"
 120 #ifdef __x86_64__
 121            "pop %%rbx\n"
 122 #else
 123            "pop %%ebx\n"
 124 #endif
 125            : "=d" (features)
 126            : /* No inputs.  */
 127            : /* Clobbered:  */ "%rax", "%rcx");
 128 #else
 129   __asm__ ("movl $1, %%eax\n\t"
 130            "cpuid\n"
 131            : "=d" (features)
 132            : /* No inputs.  */
 133            : /* Clobbered:  */ "%rax", "%rbx", "%rcx");
 134 #endif
 135   return (features & (1 << 4)) != 0;
 136 }
 137
 138 void grub_tsc_init (void);
 139 grub_uint64_t grub_tsc_get_time_ms (void);
 140
 141 #endif /* ! KERNEL_CPU_TSC_HEADER */