automake commit without merge history

grub-core/commands/i386/cpuid.c

@@ -0,0 +1,98 @@
+/* cpuid.c - test for CPU features */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2006, 2007, 2009  Free Software Foundation, Inc.
+ *  Based on gcc/gcc/config/i386/driver-i386.c
+ *
+ *  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/>.
+ */
+
+#include <grub/dl.h>
+#include <grub/misc.h>
+#include <grub/mm.h>
+#include <grub/env.h>
+#include <grub/command.h>
+#include <grub/extcmd.h>
+#include <grub/i386/cpuid.h>
+#include <grub/i18n.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))
+
+static const struct grub_arg_option options[] =
+  {
+    {"long-mode", 'l', 0, N_("Check for long mode flag (default)."), 0, 0},
+    {0, 0, 0, 0, 0, 0}
+  };
+
+#define bit_LM (1 << 29)
+
+unsigned char grub_cpuid_has_longmode = 0;
+
+static grub_err_t
+grub_cmd_cpuid (grub_extcmd_t cmd __attribute__ ((unused)),
+		int argc __attribute__ ((unused)),
+		char **args __attribute__ ((unused)))
+{
+  return grub_cpuid_has_longmode ? GRUB_ERR_NONE
+    : grub_error (GRUB_ERR_TEST_FAILURE, "false");
+}
+
+static grub_extcmd_t cmd;
+
+GRUB_MOD_INIT(cpuid)
+{
+#ifdef __x86_64__
+  /* grub-emu */
+  grub_cpuid_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);
+  grub_cpuid_has_longmode = !!(edx & bit_LM);
+done:
+#endif
+
+  cmd = grub_register_extcmd ("cpuid", grub_cmd_cpuid, GRUB_COMMAND_FLAG_BOTH,
+			      "[-l]", N_("Check for CPU features."), options);
+}
+
+GRUB_MOD_FINI(cpuid)
+{
+  grub_unregister_extcmd (cmd);
+}