vbatts/grub
1
0
Fork 0
Code Issues Pull requests Releases Wiki Activity

Recognize EFI platform even in case of mismatch between Linux and EFI.

Browse source 
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>
This commit is contained in:
Steve McIntyre 2015-03-27 14:51:51 +01:00 committed by Vladimir Serbinenko
parent ed07b7e128
commit 1a33de8b56
1 changed files with 38 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

39
grub-core/osdep/linux/platform.c
View file

@ -60,6 +60,43 @@ is_64_kernel (void)
return strcmp (un.machine, "x86_64") == 0;
}
static int
read_platform_size (void)
{
FILE *fp;
char *buf = NULL;
size_t len = 0;
int ret = 0;
/* Newer kernels can tell us directly about the size of the
* underlying firmware - let's see if that interface is there. */
fp = grub_util_fopen ("/sys/firmware/efi/fw_platform_size", "r");
if (fp != NULL)
{
if (getline (&buf, &len, fp) >= 3) /* 2 digits plus newline */
{
if (strncmp (buf, "32", 2) == 0)
ret = 32;
else if (strncmp (buf, "64", 2) == 0)
ret = 64;
}
free (buf);
fclose (fp);
}
if (ret == 0)
{
/* Unrecognised - fall back to matching the kernel size
* instead */
if (is_64_kernel ())
ret = 64;
else
ret = 32;
}
return ret;
}
const char *
grub_install_get_default_x86_platform (void)
{
@ -77,7 +114,7 @@ grub_install_get_default_x86_platform (void)
if (is_not_empty_directory ("/sys/firmware/efi"))
{
grub_util_info ("...found");
if (is_64_kernel ())
if (read_platform_size() == 64)
return "x86_64-efi";
else
return "i386-efi";