linux-sg2042/Documentation/x86
Ard Biesheuvel 8b84769a7a Documentation/x86, efi/x86: Clarify EFI handover protocol and its requirements
The EFI handover protocol was introduced on x86 to permit the boot
loader to pass a populated boot_params structure as an additional
function argument to the entry point. This allows the bootloader to
pass the base and size of a initrd image, which is more flexible
than relying on the EFI stub's file I/O routines, which can only
access the file system from which the kernel image itself was loaded
from firmware.

This approach requires a fair amount of internal knowledge regarding
the layout of the boot_params structure on the part of the boot loader,
as well as knowledge regarding the allowed placement of the initrd in
memory, and so it has been deprecated in favour of a new initrd loading
method that is based on existing UEFI protocols and best practices.

So update the x86 boot protocol documentation to clarify that the EFI
handover protocol has been deprecated, and while at it, add a note that
invoking the EFI handover protocol still requires the PE/COFF image to
be loaded properly (as opposed to simply being copied into memory).
Also, drop the code32_start header field from the list of values that
need to be provided, as this is no longer required.

Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200409130434.6736-7-ardb@kernel.org
2020-04-14 08:32:15 +02:00
..
i386 Documentation: x86: convert i386/IO-APIC.txt to reST 2019-05-08 14:34:11 -06:00
x86_64 Doc: x86: Fix a typo in mm.rst 2019-12-30 11:57:18 -07:00
amd-memory-encryption.rst Documentation: x86: convert amd-memory-encryption.txt to reST 2019-05-08 14:34:10 -06:00
boot.rst Documentation/x86, efi/x86: Clarify EFI handover protocol and its requirements 2020-04-14 08:32:15 +02:00
earlyprintk.rst Documentation: x86: convert earlyprintk.txt to reST 2019-05-08 14:34:10 -06:00
entry_64.rst Documentation: x86: convert entry_64.txt to reST 2019-05-08 14:34:09 -06:00
exception-tables.rst Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-03-31 11:04:05 -07:00
index.rst docs: remove MPX from the x86 toc 2020-02-25 03:10:22 -07:00
intel-iommu.rst docs: prevent warnings due to autosectionlabel 2020-03-20 17:01:29 -06:00
intel_txt.rst docs: x86: move two x86-specific files to x86 arch dir 2019-07-15 11:03:01 -03:00
kernel-stacks.rst Some late arriving documentation changes. In particular, this contains the 2019-05-10 13:24:53 -04:00
mds.rst x86/speculation/mds: Improve CPU buffer clear documentation 2019-05-16 09:05:12 +02:00
microcode.rst Documentation: x86: convert microcode.txt to reST 2019-05-08 14:34:11 -06:00
mtrr.rst Documentation: x86: convert mtrr.txt to reST 2019-05-08 14:34:10 -06:00
orc-unwinder.rst Documentation: x86: convert orc-unwinder.txt to reST 2019-05-08 14:34:11 -06:00
pat.rst remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
pti.rst Documentation: x86: convert pti.txt to reST 2019-05-08 14:34:10 -06:00
resctrl_ui.rst Documentation: x86: fix some typos 2019-06-20 14:16:12 -06:00
tlb.rst Documentation: x86: convert tlb.txt to reST 2019-05-08 14:34:10 -06:00
topology.rst docs: admin-guide: add a series of orphaned documents 2019-07-15 11:03:02 -03:00
tsx_async_abort.rst x86/speculation/taa: Add documentation for TSX Async Abort 2019-10-28 08:37:00 +01:00
usb-legacy-support.rst Documentation: x86: convert usb-legacy-support.txt to reST 2019-05-08 14:34:11 -06:00
zero-page.rst Documentation: x86: convert zero-page.txt to reST 2019-05-08 14:34:10 -06:00