[PATCH 0/6] efi: Start tidying up memory management

Simon Glass sjg at chromium.org
Thu Jul 25 15:56:23 CEST 2024


We have been discussing the state of EFI memory management for some
years so I thought it might be best to send a short series showing some
of the issues we have talked about.

This one just deals with memory allocation. It provides a way to detect
EFI 'page allocations' when U-Boot' malloc() should be used. It should
help us to clean up this area of U-Boot.

It also updates EFI to use U-Boot memory allocation for the pool. Most
functions use that anyway and it is much more efficient. It also avoids
allocating things 'in space' in conflict with the loaded images.

This series also includes a little patch to show more information in
the index for the EFI pages.

Note that this series is independent from Sugosh's lmb series[1],
although I believe it will point the way to simplifying some of the
later patches in that series.

Overall, some issues which should be resolved are:
- allocation inconsistency, e.g. efi_add_protocol() uses malloc() but
  efi_dp_dup() does not (this series makes a start)
- change efi_bl_init() to register events later, when the devices are
  actually used
- rather than efi_set_bootdev(), provide a bootstd way to take note of
  the device images came from and allow EFI to query that when needed
- EFI_LOADER_BOUNCE_BUFFER - can use U-Boot bounce buffers?

Minor questions on my mind:
- is unaligned access useful? Is there a performance penalty?
- API confusion about whether something is an address or a pointer

[1] https://patchwork.ozlabs.org/project/uboot/list/?series=416441


Simon Glass (6):
  doc: Show more information in efi index
  efi: Convert device_path allocation to use malloc()
  efi: Allow monitoring of page allocations
  efi: Avoid pool allocation in efi_get_memory_map_alloc()
  efi: Use malloc() for the EFI pool
  efi: Show the location of the bounce buffer

 doc/develop/uefi/index.rst               |   2 +-
 include/efi_loader.h                     |  24 ++++
 lib/efi_loader/efi_bootbin.c             |  10 ++
 lib/efi_loader/efi_device_path.c         |  43 ++++---
 lib/efi_loader/efi_device_path_to_text.c |   2 +-
 lib/efi_loader/efi_memory.c              | 148 +++++++++++------------
 lib/efi_loader/efi_setup.c               |   7 ++
 7 files changed, 133 insertions(+), 103 deletions(-)

-- 
2.34.1



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