--- Begin Message ---
- To: grub-devel@gnu.org
- Subject: [PATCH] Fail gracefuly when attempting to load 64-bit kFreeBSD on IA32 CPU
- From: Robert Millan <rmh@aybabtu.com>
- Date: Wed, 7 Oct 2009 23:13:34 +0200
- Message-id: <20091007211334.GA31055@thorin>
- Reply-to: The development of GRUB 2 <grub-devel@gnu.org>
--
Robert Millan
The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
how) you may access your data; but nobody's threatening your freedom: we
still allow you to remove your data and not access it at all."
2009-10-07 Robert Millan <rmh.grub@aybabtu.com>
Fail gracefuly when attempting to load 64-bit kFreeBSD on IA32 CPU.
* include/grub/i386/cpuid.h: New file.
* commands/i386/cpuid.c: Include `<grub/i386/cpuid.h>'.
(has_longmode): Rename to ...
(grub_cpuid_has_longmode): ... this. Update all users. Remove
`unsigned' attribute.
* loader/i386/bsd.c: Include `<grub/i386/cpuid.h>'.
(grub_bsd_load_elf): Fail if load of 64-bit kernel was requested
on a CPU that doesn't implement AMD64 instruction set.
Index: include/grub/i386/cpuid.h
===================================================================
--- include/grub/i386/cpuid.h (revision 0)
+++ include/grub/i386/cpuid.h (revision 0)
@@ -0,0 +1,19 @@
+/*
+ * 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/>.
+ */
+
+extern unsigned char grub_cpuid_has_longmode;
Index: commands/i386/cpuid.c
===================================================================
--- commands/i386/cpuid.c (revision 2626)
+++ commands/i386/cpuid.c (working copy)
@@ -1,7 +1,7 @@
/* cpuid.c - test for CPU features */
/*
* GRUB -- GRand Unified Bootloader
- * Copyright (C) 2006, 2007 Free Software Foundation, Inc.
+ * 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
@@ -24,6 +24,7 @@
#include <grub/env.h>
#include <grub/command.h>
#include <grub/extcmd.h>
+#include <grub/i386/cpuid.h>
#define cpuid(num,a,b,c,d) \
asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1" \
@@ -38,14 +39,14 @@ static const struct grub_arg_option options[] =
#define bit_LM (1 << 29)
-static unsigned char has_longmode = 0;
+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 has_longmode ? GRUB_ERR_NONE
+ return grub_cpuid_has_longmode ? GRUB_ERR_NONE
: grub_error (GRUB_ERR_TEST_FAILURE, "false");
}
@@ -55,7 +56,7 @@ GRUB_MOD_INIT(cpuid)
{
#ifdef __x86_64__
/* grub-emu */
- has_longmode = 1;
+ grub_cpuid_has_longmode = 1;
#else
unsigned int eax, ebx, ecx, edx;
unsigned int max_level;
@@ -82,7 +83,7 @@ GRUB_MOD_INIT(cpuid)
goto done;
cpuid (0x80000001, eax, ebx, ecx, edx);
- has_longmode = !!(edx & bit_LM);
+ grub_cpuid_has_longmode = !!(edx & bit_LM);
done:
#endif
Index: loader/i386/bsd.c
===================================================================
--- loader/i386/bsd.c (revision 2626)
+++ loader/i386/bsd.c (working copy)
@@ -19,6 +19,7 @@
#include <grub/loader.h>
#include <grub/cpu/loader.h>
#include <grub/cpu/bsd.h>
+#include <grub/i386/cpuid.h>
#include <grub/machine/init.h>
#include <grub/machine/memory.h>
#include <grub/memory.h>
@@ -871,6 +872,9 @@ grub_bsd_load_elf (grub_elf_t elf)
{
is_64bit = 1;
+ if (! grub_cpuid_has_longmode)
+ return grub_error (GRUB_ERR_BAD_OS, "Your CPU does not implement AMD64 architecture.");
+
/* FreeBSD has 64-bit entry point. */
if (kernel_type == KERNEL_TYPE_FREEBSD)
{
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