[PATCH] doc: efi: Update for the 64-bit app
Simon Glass
sjg at chromium.org
Sun Sep 3 17:15:51 CEST 2023
The 64-bit app is supported now, so update the documentation.
Signed-off-by: Simon Glass <sjg at chromium.org>
---
doc/develop/uefi/u-boot_on_efi.rst | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)
diff --git a/doc/develop/uefi/u-boot_on_efi.rst b/doc/develop/uefi/u-boot_on_efi.rst
index acad6397e81d..1746965e7eab 100644
--- a/doc/develop/uefi/u-boot_on_efi.rst
+++ b/doc/develop/uefi/u-boot_on_efi.rst
@@ -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).
@@ -261,8 +259,6 @@ 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).
--
2.42.0.283.g2d96d420d3-goog
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