1 files changed, 85 insertions, 0 deletions
diff --git a/include/grub/i386/cpuid.h b/include/grub/i386/cpuid.h
new file mode 100644
index 0000000..f7ae4b0
--- /dev/null
+++ b/include/grub/i386/cpuid.h
@@ -0,0 +1,85 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2009  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GRUB_CPU_CPUID_HEADER
+#define GRUB_CPU_CPUID_HEADER 1
+
+extern unsigned char grub_cpuid_has_longmode;
+extern unsigned char grub_cpuid_has_pae;
+
+#ifdef __x86_64__
+
+static __inline int
+grub_cpu_is_cpuid_supported (void)
+{
+  grub_uint64_t id_supported;
+
+  __asm__ ("pushfq\n\t"
+           "popq %%rax             /* Get EFLAGS into EAX */\n\t"
+           "movq %%rax, %%rcx      /* Save original flags in ECX */\n\t"
+           "xorq $0x200000, %%rax  /* Flip ID bit in EFLAGS */\n\t"
+           "pushq %%rax            /* Store modified EFLAGS on stack */\n\t"
+           "popfq                  /* Replace current EFLAGS */\n\t"
+           "pushfq                 /* Read back the EFLAGS */\n\t"
+           "popq %%rax             /* Get EFLAGS into EAX */\n\t"
+           "xorq %%rcx, %%rax      /* Check if flag could be modified */\n\t"
+           : "=a" (id_supported)
+           : /* No inputs.  */
+           : /* Clobbered:  */ "%rcx");
+
+  return id_supported != 0;
+}
+
+#else
+
+static __inline int
+grub_cpu_is_cpuid_supported (void)
+{
+  grub_uint32_t id_supported;
+
+  __asm__ ("pushfl\n\t"
+           "popl %%eax             /* Get EFLAGS into EAX */\n\t"
+           "movl %%eax, %%ecx      /* Save original flags in ECX */\n\t"
+           "xorl $0x200000, %%eax  /* Flip ID bit in EFLAGS */\n\t"
+           "pushl %%eax            /* Store modified EFLAGS on stack */\n\t"
+           "popfl                  /* Replace current EFLAGS */\n\t"
+           "pushfl                 /* Read back the EFLAGS */\n\t"
+           "popl %%eax             /* Get EFLAGS into EAX */\n\t"
+           "xorl %%ecx, %%eax      /* Check if flag could be modified */\n\t"
+           : "=a" (id_supported)
+           : /* No inputs.  */
+           : /* Clobbered:  */ "%rcx");
+
+  return id_supported != 0;
+}
+
+#endif
+
+#ifdef __PIC__
+#define grub_cpuid(num,a,b,c,d) \
+  asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1" \
+                : "=a" (a), "=r" (b), "=c" (c), "=d" (d)  \
+                : "0" (num))
+#else
+#define grub_cpuid(num,a,b,c,d) \
+  asm volatile ("cpuid" \
+                : "=a" (a), "=b" (b), "=c" (c), "=d" (d)  \
+                : "0" (num))
+#endif
+
+#endif