Hi Simon On Sun, 3 Dec 2023 at 19:44, Simon Glass <s...@chromium.org> wrote: > > Hi Heinrich, Ilias, > > I had a bit of a look at how memory is allocated in EFI. > > I see that efi_memory_init() is called quite early in U-Boot. It > sometimes allocates memory for a bounce buffer, placing it somewhere > in memory. How do we know that that memory is free and not being used > by U-Boot? > > To answer my own question, it excludes U-Boot's malloc() region from > the map, so that it cannot overwrite that. > > But then, what if we use lmb and start loading images into memory. > Won't that conflict with EFI?
Yes, Heinrich tried to fix parts of this with commit 06d514d77c37 and we have a 'todo' in the efi subsystem for a few years now [0] Michal (+cc'ed) has also pinged me for similar issues in the past. > > I also see that efi_allocate_pages() is called to allocate memory in > the EFI code. But this just grabs memory from 'anywhere'...it doesn't > respect the U-Boot malloc region. > > It seems to me that most of the memory allocation in EFI should be > done using malloc(). Of course the boot services need to > efi_allocate_pages(), etc., but I am not sure that the internal tables > should be skipping malloc()? > > What do you think? I think that LMB, EFI and the whole memory reservations is a bit of a mess. Tom and I discussed this a bit in the past but I'll start working on it. It needs fixing, but without looking at the code first, I can't provide any useful feedback [0] https://source.denx.de/u-boot/custodians/u-boot-efi/-/issues/2 Thanks /Ilias > > Regards, > Simon
