Commit ef16bcc7 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Jonathan Corbet

efi-stub.txt: standardize document format

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- use proper markups for titles;
- identify literal blocks.
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 7c6a2d22
The EFI Boot Stub =================
--------------------------- The EFI Boot Stub
=================
On the x86 and ARM platforms, a kernel zImage/bzImage can masquerade On the x86 and ARM platforms, a kernel zImage/bzImage can masquerade
as a PE/COFF image, thereby convincing EFI firmware loaders to load as a PE/COFF image, thereby convincing EFI firmware loaders to load
...@@ -25,7 +26,8 @@ a certain sense it *IS* the boot loader. ...@@ -25,7 +26,8 @@ a certain sense it *IS* the boot loader.
The EFI boot stub is enabled with the CONFIG_EFI_STUB kernel option. The EFI boot stub is enabled with the CONFIG_EFI_STUB kernel option.
**** How to install bzImage.efi How to install bzImage.efi
--------------------------
The bzImage located in arch/x86/boot/bzImage must be copied to the EFI The bzImage located in arch/x86/boot/bzImage must be copied to the EFI
System Partition (ESP) and renamed with the extension ".efi". Without System Partition (ESP) and renamed with the extension ".efi". Without
...@@ -37,14 +39,16 @@ may not need to be renamed. Similarly for arm64, arch/arm64/boot/Image ...@@ -37,14 +39,16 @@ may not need to be renamed. Similarly for arm64, arch/arm64/boot/Image
should be copied but not necessarily renamed. should be copied but not necessarily renamed.
**** Passing kernel parameters from the EFI shell Passing kernel parameters from the EFI shell
--------------------------------------------
Arguments to the kernel can be passed after bzImage.efi, e.g. Arguments to the kernel can be passed after bzImage.efi, e.g.::
fs0:> bzImage.efi console=ttyS0 root=/dev/sda4 fs0:> bzImage.efi console=ttyS0 root=/dev/sda4
**** The "initrd=" option The "initrd=" option
--------------------
Like most boot loaders, the EFI stub allows the user to specify Like most boot loaders, the EFI stub allows the user to specify
multiple initrd files using the "initrd=" option. This is the only EFI multiple initrd files using the "initrd=" option. This is the only EFI
...@@ -54,9 +58,9 @@ kernel when it boots. ...@@ -54,9 +58,9 @@ kernel when it boots.
The path to the initrd file must be an absolute path from the The path to the initrd file must be an absolute path from the
beginning of the ESP, relative path names do not work. Also, the path beginning of the ESP, relative path names do not work. Also, the path
is an EFI-style path and directory elements must be separated with is an EFI-style path and directory elements must be separated with
backslashes (\). For example, given the following directory layout, backslashes (\). For example, given the following directory layout::
fs0:> fs0:>
Kernels\ Kernels\
bzImage.efi bzImage.efi
initrd-large.img initrd-large.img
...@@ -66,7 +70,7 @@ fs0:> ...@@ -66,7 +70,7 @@ fs0:>
initrd-medium.img initrd-medium.img
to boot with the initrd-large.img file if the current working to boot with the initrd-large.img file if the current working
directory is fs0:\Kernels, the following command must be used, directory is fs0:\Kernels, the following command must be used::
fs0:\Kernels> bzImage.efi initrd=\Kernels\initrd-large.img fs0:\Kernels> bzImage.efi initrd=\Kernels\initrd-large.img
...@@ -76,7 +80,8 @@ which understands relative paths, whereas the rest of the command line ...@@ -76,7 +80,8 @@ which understands relative paths, whereas the rest of the command line
is passed to bzImage.efi. is passed to bzImage.efi.
**** The "dtb=" option The "dtb=" option
-----------------
For the ARM and arm64 architectures, we also need to be able to provide a For the ARM and arm64 architectures, we also need to be able to provide a
device tree to the kernel. This is done with the "dtb=" command line option, device tree to the kernel. This is done with the "dtb=" command line option,
......
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