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

[Simon Glass]

Hi Ilias,

On Thu, Jul 25, 2024, 08:26 Ilias Apalodimas <ilias.apalodimas at linaro.org>
wrote:

> Hi Simon
>
> On Thu, 25 Jul 2024 at 16:58, Simon Glass <sjg at chromium.org> wrote:
> >
> > 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)
>
> The EFI memory allocations and mappings are described in the EFI spec.
> Look at chapter 7.2 Memory Allocation Services. This patchset breaks
> various aspects of the spec, since the metadata needed for the EFI
> memory map is not kept from malloc. The reason efi_add_protocol() uses
> calloc, is that this is memory used from our internal implementation
> of the protocol linked list -- IOW how to search and identify
> protocols that we add in a list and not UEFI boot or runtime services.


Er, yes, I am aware of that chapter:-)

Can you please be more specific about which various aspects this will break?

Also please let me know if you have comments on any of the patches.

Regards,
Simon


> Thanks
> /Ilias
>
>
> > - 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
> >
>