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doc: efi: Update for the 64-bit app

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The 64-bit app is supported now, so update the documentation.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
This commit is contained in:
Simon Glass
2023-09-03 09:15:51 -06:00
committed by Heinrich Schuchardt
parent 5d1fa6b6a6
commit 063536a781
1 changed files with 11 additions and 15 deletions
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26
doc/develop/uefi/u-boot_on_efi.rst
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@@ -31,14 +31,12 @@ Only x86 is supported at present. If you are using EFI on another architecture
you may want to reconsider. However, much of the code is generic so could be
ported.
U-Boot supports running as an EFI application for 32-bit EFI only. This is
not very useful since only a serial port is provided. You can look around at
memory and type 'help' but that is about it.
U-Boot supports running as an EFI application for both 32- and 64-bit EFI.
More usefully, U-Boot supports building itself as a payload for either 32-bit
or 64-bit EFI. U-Boot is packaged up and loaded in its entirety by EFI. Once
started, U-Boot changes to 32-bit mode (currently) and takes over the
machine. You can use devices, boot a kernel, etc.
U-Boot supports building itself as a payload for either 32-bit or 64-bit EFI.
U-Boot is packaged up and loaded in its entirety by EFI. Once started, U-Boot
changes to 32-bit mode (currently) and takes over the machine. You can use
devices, boot a kernel, etc.
Build Instructions
@@ -47,9 +45,9 @@ First choose a board that has EFI support and obtain an EFI implementation
for that board. It will be either 32-bit or 64-bit. Alternatively, you can
opt for using QEMU [1] and the OVMF [2], as detailed below.
To build U-Boot as an EFI application (32-bit EFI required), enable CONFIG_EFI
and CONFIG_EFI_APP. The efi-x86_app config (efi-x86_app32_defconfig) is set up
for this. Just build U-Boot as normal, e.g.::
To build U-Boot as an EFI application, enable CONFIG_EFI and CONFIG_EFI_APP.
The efi-x86_app32 and efi-x86_app64 configs are set up for this. Just build
U-Boot as normal, e.g.::
make efi-x86_app32_defconfig
make
@@ -189,9 +187,9 @@ interrupts disabled at present.
32/64-bit
~~~~~~~~~
While the EFI application can in principle be built as either 32- or 64-bit,
only 32-bit is currently supported. This means that the application can only
be used with 32-bit EFI.
While the EFI application can be built as either 32- or 64-bit, you need to be
careful to build the correct one so that your UEFI firmware can start it. Most
UEFI images are 64-bit at present.
The payload stub can be build as either 32- or 64-bits. Only a small amount
of code is built this way (see the extra- line in lib/efi/Makefile).
@@ -345,8 +343,6 @@ This work could be extended in a number of ways:
- Add ARM support
- Add 64-bit application support (in progress)
- Figure out how to solve the interrupt problem
- Add more drivers to the application side (e.g.USB, environment access).