[PATCH 5/6] efi: Use malloc() for the EFI pool

[Ilias Apalodimas]

hi Simon,

On Thu, 1 Aug 2024 at 19:14, Simon Glass <sjg at chromium.org> wrote:
>
> Hi Ilias,
>
> On Thu, 1 Aug 2024 at 04:14, Ilias Apalodimas
> <ilias.apalodimas at linaro.org> wrote:
> >
> > Hi Tom
> >
> > On Wed, 31 Jul 2024 at 20:17, Tom Rini <trini at konsulko.com> wrote:
> > >
> > > On Wed, Jul 31, 2024 at 08:39:23AM -0600, Simon Glass wrote:
> > >
> > > [snip]
> > > > > > > so that
> > > > > > > step three can be seeing what tweaks may be needed in where things
> > > > > > > allocate memory.
> > > > > >
> > > > > > So my series is step 3?
> > > > >
> > > > > Or at least understanding what the problems may still be, yes.
> > > >
> > > > In that case I would like to clean up EFI's memory management before
> > > > doing step 2, since I believe many of the problems will just go away
> > > > if we can get that right.
> > >
> > > Well, I think that's where some of the big points of contention are,
> > > yes. You say "fix" and Ilias and Heinrich say "but the spec".
> >
> > Using malloc on efi_allocate_pool() would be ok spec-wise. Simon's
> > current patch is ignoring the efi memory type metadata we have to
> > preserve. On top of that using malloc for a *single* memory type, just
> > kicks the can down the road until an EFI app chooses a different type
> > and we are back to the same problem.
> >
> > It's fine to teach efi_allocate_pool to use malloc with 2 conditions
> > - memory types are preserved for all allocations
> > - malloc area is big enough
>
> OK thanks I will take a look.
>
> I see the EFI code eventually dealing with memory in two distinct phases:
> - before the app runs: we try to keep memory usage to within areas people expect
> - once the app runs: t doesn't matter anymore

You need to define 'the app' a bit better.
An app for example may load, use efi_allocate_pool to inject some
runtime memory data which the OS expects and exit. The you would load
you OS (which is really another EFI app). In general I wouldn't make
any assumptions on what EFI apps will do wrt to memory

/Ilias
>
> >
> > Cheers
> > /Ilias
> >
> > >
> > > Perhaps once step one is done it will be easier to find a way to address
> > > your concerns without also breaking "the spec".
>
> Regards,
> Simon