1a33de8b56
Some x86 systems might be capable of running a 64-bit Linux kernel but only use a 32-bit EFI (e.g. Intel Bay Trail systems). It's useful for grub-install to be able to recognise such systems, to set the default x86 platform correctly. To allow grub-install to know the size of the firmware rather than just the size of the kernel, there is now an extra EFI sysfs file to describe the underlying firmware. Read that if possible, otherwise fall back to the kernel type as before. Signed-off-by: Steve McIntyre <steve@einval.com>
132 lines
3 KiB
C
132 lines
3 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2013 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <grub/util/install.h>
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#include <grub/emu/exec.h>
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#include <grub/emu/misc.h>
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#include <sys/types.h>
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#include <dirent.h>
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#include <string.h>
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#include <sys/utsname.h>
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static int
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is_not_empty_directory (const char *dir)
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{
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DIR *d;
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struct dirent *de;
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d = opendir (dir);
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if (!d)
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return 0;
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while ((de = readdir (d)))
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{
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if (strcmp (de->d_name, ".") == 0
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|| strcmp (de->d_name, "..") == 0)
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continue;
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closedir (d);
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return 1;
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}
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closedir (d);
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return 0;
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}
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static int
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is_64_kernel (void)
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{
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struct utsname un;
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if (uname (&un) < 0)
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return 0;
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return strcmp (un.machine, "x86_64") == 0;
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}
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static int
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read_platform_size (void)
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{
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FILE *fp;
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char *buf = NULL;
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size_t len = 0;
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int ret = 0;
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/* Newer kernels can tell us directly about the size of the
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* underlying firmware - let's see if that interface is there. */
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fp = grub_util_fopen ("/sys/firmware/efi/fw_platform_size", "r");
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if (fp != NULL)
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{
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if (getline (&buf, &len, fp) >= 3) /* 2 digits plus newline */
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{
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if (strncmp (buf, "32", 2) == 0)
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ret = 32;
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else if (strncmp (buf, "64", 2) == 0)
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ret = 64;
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}
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free (buf);
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fclose (fp);
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}
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if (ret == 0)
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{
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/* Unrecognised - fall back to matching the kernel size
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* instead */
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if (is_64_kernel ())
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ret = 64;
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else
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ret = 32;
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}
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return ret;
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}
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const char *
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grub_install_get_default_x86_platform (void)
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{
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/*
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On Linux, we need the efivars kernel modules.
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If no EFI is available this module just does nothing
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besides a small hello and if we detect efi we'll load it
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anyway later. So it should be safe to
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try to load it here.
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*/
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grub_util_exec_redirect_all ((const char * []){ "modprobe", "efivars", NULL },
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NULL, NULL, "/dev/null");
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grub_util_info ("Looking for /sys/firmware/efi ..");
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if (is_not_empty_directory ("/sys/firmware/efi"))
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{
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grub_util_info ("...found");
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if (read_platform_size() == 64)
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return "x86_64-efi";
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else
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return "i386-efi";
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}
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grub_util_info ("... not found. Looking for /proc/device-tree ..");
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if (is_not_empty_directory ("/proc/device-tree"))
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{
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grub_util_info ("...found");
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return "i386-ieee1275";
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}
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grub_util_info ("... not found");
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return "i386-pc";
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}
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