The method used to work out whether we were booted by EFI firmware or
via a boot loader is broken. Because efi_main() is always executed
when booting from a boot loader we will dereference invalid pointers
either on the stack (CONFIG_X86_32) or contained in %rdx
(CONFIG_X86_64) when searching for an EFI System Table signature.
Instead of dereferencing these invalid system table pointers, add a
new entry point that is only used when booting from EFI firmware, when
we know the pointer arguments will be valid. With this change legacy
boot loaders will no longer execute efi_main(), but will instead skip
EFI stub initialisation completely.
[ hpa: Marking this for urgent/stable since it is a regression when
the option is enabled; without the option the patch has no effect ]
Signed-off-by: Matt Fleming <matt.hfleming@intel.com>
Link: http://lkml.kernel.org/r/1334584744.26997.14.camel@mfleming-mobl1.ger.corp.intel.com
Reported-by: Jordan Justen <jordan.l.justen@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org> v3.3
It would appear that we never actually generated a correct CRC when
building on a bigendian machine. Depending on the word size, we would
either generate an all-zero CRC (64-bit machine) or a byte-swapped
CRC (32-bit machine.) Fix the types used so we don't arbitrarily use
a 64-bit word to hold 32-bit numbers, and pass the CRC through
put_unaligned_le32() like all the other numbers.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Bowler <nbowler@elliptictech.com>
Link: http://lkml.kernel.org/r/20120229111322.9eb4b23ff1672e8853ad3b3b@canb.auug.org.au
We include <sys/sysmacros.h> and <asm/boot.h>, but none of those
header files actually provide anything this file needs. Furthermore,
it breaks cross-compilation, so just remove them.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Bowler <nbowler@elliptictech.com>
Link: http://lkml.kernel.org/r/20120229111322.9eb4b23ff1672e8853ad3b3b@canb.auug.org.au
We may need to convert the endianness of the data we read from/write
to 'buf', so let's use {get,put}_unaligned_le32() to do that. Failure
to do so can result in accessing invalid memory, leading to a
segfault. Stephen Rothwell noticed this bug while cross-building an
x86_64 allmodconfig kernel on PowerPC.
We need to read from and write to 'buf' a byte at a time otherwise
it's possible we'll perform an unaligned access, which can lead to bus
errors when cross-building an x86 kernel on risc architectures.
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Nick Bowler <nbowler@elliptictech.com>
Tested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1330436245-24875-6-git-send-email-matt@console-pimps.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
There is currently a large divide between kernel development and the
development of EFI boot loaders. The idea behind this patch is to give
the kernel developers full control over the EFI boot process. As
H. Peter Anvin put it,
"The 'kernel carries its own stub' approach been very successful in
dealing with BIOS, and would make a lot of sense to me for EFI as
well."
This patch introduces an EFI boot stub that allows an x86 bzImage to
be loaded and executed by EFI firmware. The bzImage appears to the
firmware as an EFI application. Luckily there are enough free bits
within the bzImage header so that it can masquerade as an EFI
application, thereby coercing the EFI firmware into loading it and
jumping to its entry point. The beauty of this masquerading approach
is that both BIOS and EFI boot loaders can still load and run the same
bzImage, thereby allowing a single kernel image to work in any boot
environment.
The EFI boot stub supports multiple initrds, but they must exist on
the same partition as the bzImage. Command-line arguments for the
kernel can be appended after the bzImage name when run from the EFI
shell, e.g.
Shell> bzImage console=ttyS0 root=/dev/sdb initrd=initrd.img
v7:
- Fix checkpatch warnings.
v6:
- Try to allocate initrd memory just below hdr->inird_addr_max.
v5:
- load_options_size is UTF-16, which needs dividing by 2 to convert
to the corresponding ASCII size.
v4:
- Don't read more than image->load_options_size
v3:
- Fix following warnings when compiling CONFIG_EFI_STUB=n
arch/x86/boot/tools/build.c: In function ‘main’:
arch/x86/boot/tools/build.c:138:24: warning: unused variable ‘pe_header’
arch/x86/boot/tools/build.c:138:15: warning: unused variable ‘file_sz’
- As reported by Matthew Garrett, some Apple machines have GOPs that
don't have hardware attached. We need to weed these out by
searching for ones that handle the PCIIO protocol.
- Don't allocate memory if no initrds are on cmdline
- Don't trust image->load_options_size
Maarten Lankhorst noted:
- Don't strip first argument when booted from efibootmgr
- Don't allocate too much memory for cmdline
- Don't update cmdline_size, the kernel considers it read-only
- Don't accept '\n' for initrd names
v2:
- File alignment was too large, was 8192 should be 512. Reported by
Maarten Lankhorst on LKML.
- Added UGA support for graphics
- Use VIDEO_TYPE_EFI instead of hard-coded number.
- Move linelength assignment until after we've assigned depth
- Dynamically fill out AddressOfEntryPoint in tools/build.c
- Don't use magic number for GDT/TSS stuff. Requested by Andi Kleen
- The bzImage may need to be relocated as it may have been loaded at
a high address address by the firmware. This was required to get my
macbook booting because the firmware loaded it at 0x7cxxxxxx, which
triggers this error in decompress_kernel(),
if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
error("Destination address too large");
Cc: Mike Waychison <mikew@google.com>
Cc: Matthew Garrett <mjg@redhat.com>
Tested-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1321383097.2657.9.camel@mfleming-mobl1.ger.corp.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This has been obsoleted by the root= commandline and the rdev utility
for many, many years. People who still depend on this will surely
have a copy of the rdev utility around, the rest of the world gets rid
of another piece of buildhost-dependent data in the build. Thanks to
Paul Bolle for the build.c cleanup.
Cc: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Link: http://lkml.kernel.org/r/1302607824-24699-1-git-send-email-mmarek@suse.cz
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Impact: obsolete feature removal
The zImage kernel format has been functionally unused for a very long
time. It is just barely possible to build a modern kernel that still
fits within the zImage size limit, but it is highly unlikely that
anyone ever uses it. Furthermore, although it is still supported by
most bootloaders, it has been at best poorly tested (or not tested at
all); some bootloaders are even known to not support zImage at all and
not having even noticed.
Also remove some really obsolete constants that no longer have any
meaning.
LKML-Reference: <49B703D4.1000008@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Matt Fleming
H. Peter Anvin
Michal Marek
Ian Campbell
Thomas Gleixner