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[15/15] efi_loader: Add documentation for the EFI log

Message ID 20241028124815.47262-16-sjg@chromium.org
State Rejected, archived
Delegated to: Heinrich Schuchardt
Headers show
Series efi_loader: Add support for logging to a buffer | expand

Commit Message

Simon Glass Oct. 28, 2024, 12:48 p.m. UTC 
Add a note in the documentation about this feature.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

 doc/develop/uefi/uefi.rst | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
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Patch

diff --git a/doc/develop/uefi/uefi.rst b/doc/develop/uefi/uefi.rst
index 0760ca91d4f..eade13dcfa1 100644
--- a/doc/develop/uefi/uefi.rst
+++ b/doc/develop/uefi/uefi.rst
@@ -963,6 +963,28 @@  This driver is only available if U-Boot is configured with::
     CONFIG_BLK=y
     CONFIG_PARTITIONS=y
 
+Logging
+-------
+
+The EFI subsystem supports logging of boot-services calls to a memory area. The
+log can then be shown using the ``efidebug log`` command. Note that only a few
+calls are logged at present.
+
+To enable this feature::
+
+    CONFIG_EFI_LOG=y
+    CONFIG_EFI_LOG_SIZE=0x4000
+    CONFIG_BLOBLIST_SIZE_RELOC=0x5000
+
+The bloblist size must be set to larger than the EFI size. For now the log size
+is fixed at the start.
+
+Logging is performed within the internal U-Boot functions, not at the
+boot-services interface. This makes it possible to log EFI calls made by U-Boot
+itself, such as memory allocations.
+
+See the :doc:`/usage/cmd/efidebug` (*log* subcommand) for more information.
+
 Miscellaneous
 -------------