[PATCH v4 4/5] efi: Reserve some memory for initial use
Tom Rini
trini at konsulko.com
Tue Oct 15 16:30:38 CEST 2024
On Tue, Oct 15, 2024 at 07:12:21AM -0600, Simon Glass wrote:
> Hi Tom,
>
> On Mon, 14 Oct 2024 at 15:55, Tom Rini <trini at konsulko.com> wrote:
> >
> > On Mon, Oct 14, 2024 at 03:50:51PM -0600, Simon Glass wrote:
> > > Hi Tom,
> > >
> > > On Mon, 14 Oct 2024 at 15:42, Tom Rini <trini at konsulko.com> wrote:
> > > >
> > > > On Mon, Oct 14, 2024 at 02:19:56PM -0600, Simon Glass wrote:
> > > > > Hi,
> > > > >
> > > > > On Fri, 11 Oct 2024 at 23:47, Ilias Apalodimas
> > > > > <ilias.apalodimas at linaro.org> wrote:
> > > > > >
> > > > > > Hi Tom
> > > > > >
> > > > > > On Sat, 12 Oct 2024 at 04:27, Tom Rini <trini at konsulko.com> wrote:
> > > > > > >
> > > > > > > On Sat, Oct 12, 2024 at 12:01:54AM +0200, Heinrich Schuchardt wrote:
> > > > > > > >
> > > > > > > >
> > > > > > > > Am 11. Oktober 2024 23:21:25 MESZ schrieb Simon Glass <sjg at chromium.org>:
> > > > > > > > >The 'point of cooperation' is where U-Boot starts allowing EFI to use
> > > > > > > > >memory outside of the U-Boot region. Until that point, it is desirable
> > > > > > > > >to keep more below U-Boot free for loading images.
> > > > > > > > >
> > > > > > > > >Reserve a small region for this purpose.
> > > > > > > >
> > > > > > > > Your commit message provides no clue why this should be needed.
> > > > >
> > > > > Yes, I hadn't realised that people didn't understand what I was
> > > > > getting at. Tom asked the same question on irc.
> > > > >
> > > > > It allows us to separate the lmb allocations from the EFI allocations,
> > > > > so we don't need to have them both in sync. We use lmb for loading
> > > > > images, then EFI takes over and does what it likes, respecting the
> > > > > existing lmb reservations.
> > > >
> > > > But, again, LMB is not for loading of images. It's for dealing with
> > > > memory reservations of various types.
> > >
> > > Up until recently, I believe, my statement was true, but in any case,
> > > this isn't gemaine to the issue here.
> > >
> > > The point is, this is a useful distinction, allowing us to avoid the
> > > complexity of keeping them in sync, and avoid putting this pain on
> > > people who are not using EFI. We are either in U-Boot code, in which
> > > case lmb rules, or we are going into an app, in which case EFI rules
> > > (but must read in the lmb info).
> > >
> > > We are going to end up with people turning off EFI_LOADER because it
> > > behaves so badly.
> >
> > Frankly, in hind sight I should not have agreed to split the LMB rework
> > between "everything else" and "EFI" in hopes that we would then be able
> > to get the "EFI" part of this agreed upon. It's "behaving badly" right
> > now because we merged half of the changes in the hopes that we could get
> > your agreement on the rest of them fairly quickly. This is not
> > happening, however.
>
> Well, another option would be to revert the problem patch (or two) and
> do this work with careful consideration of the impacts, taking account
> of my architectural objections.
Well, no. You have objections that no one else has agreed with and most
of the active developers in the areas in question have objections to
your designs. So no, I repeat myself. My mistake here was taking half of
the work in, rather than all of the work in.
--
Tom
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