2007-05-19 Robert Millan <rmh@aybabtu.com>

* commands/i386/cpuid.c: New module. * DISTLIST: Add it. * conf/i386-efi.rmk: Enable cpuid.mod. * conf/i386-pc.rmk: Likewise.
2007-05-20 07:20:43 +00:00 · 2007-05-20 07:20:43 +00:00 · 5beb22914d
commit 5beb22914d
parent 7262eca1e3
6 changed files with 178 additions and 7 deletions
--- a/commands/i386/cpuid.c
+++ b/commands/i386/cpuid.c
@ -0,0 +1,94 @@
+/* cpuid.c - test for CPU features */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2006, 2007  Free Software Foundation, Inc.
+ *  Based on gcc/gcc/config/i386/driver-i386.c
+ *
+ *  This program 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 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program 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 this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <grub/normal.h>
+#include <grub/dl.h>
+#include <grub/arg.h>
+#include <grub/misc.h>
+#include <grub/mm.h>
+#include <grub/env.h>
+
+#define 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))
+
+#define bit_LM (1 << 29)
+
+unsigned char has_longmode = 0;
+
+static const struct grub_arg_option options[] =
+  {
+    {"long-mode", 'l', 0, "check for long mode flag (default)", 0, 0},
+    {0, 0, 0, 0, 0, 0}
+  };
+
+static grub_err_t
+grub_cmd_cpuid (struct grub_arg_list *state __attribute__ ((unused)), int argc,
+	       char **args)
+
+{
+  return !has_longmode;
+}
+
+GRUB_MOD_INIT(cpuid)
+{
+#ifdef __x86_64__
+  /* grub-emu */
+  has_longmode = 1;
+#else
+  unsigned int eax, ebx, ecx, edx;
+  unsigned int max_level;
+  unsigned int ext_level;
+
+  /* See if we can use cpuid.  */
+  asm volatile ("pushfl; pushfl; popl %0; movl %0,%1; xorl %2,%0;"
+		"pushl %0; popfl; pushfl; popl %0; popfl"
+		: "=&r" (eax), "=&r" (ebx)
+		: "i" (0x00200000));
+  if (((eax ^ ebx) & 0x00200000) == 0)
+    goto done;
+
+  /* Check the highest input value for eax.  */
+  cpuid (0, eax, ebx, ecx, edx);
+  /* We only look at the first four characters.  */
+  max_level = eax;
+  if (max_level == 0)
+    goto done;
+
+  cpuid (0x80000000, eax, ebx, ecx, edx);
+  ext_level = eax;
+  if (ext_level < 0x80000000)
+    goto done;
+
+  cpuid (0x80000001, eax, ebx, ecx, edx);
+  has_longmode = !!(edx & bit_LM);
+done:
+#endif
+
+  grub_register_command ("cpuid", grub_cmd_cpuid, GRUB_COMMAND_FLAG_CMDLINE,
+			 "cpuid", "Check for CPU features", options);
+}
+
+GRUB_MOD_FINI(cpuid)
+{
+  grub_unregister_command ("cpuid");
+}