On 1/11/23 18:40, Mark Kettenis wrote:
Date: Wed, 11 Jan 2023 17:59:27 +0100
From: Heinrich Schuchardt <heinrich.schucha...@canonical.com>
On 1/11/23 17:48, Simon Glass wrote:
Hi,
On Wed, 11 Jan 2023 at 06:59, Tom Rini <tr...@konsulko.com> wrote:
On Wed, Jan 11, 2023 at 08:43:37AM +0100, Heinrich Schuchardt wrote:
On 1/11/23 01:15, Simon Glass wrote:
Hi Heinrich,
On Mon, 9 Jan 2023 at 13:53, Heinrich Schuchardt
<heinrich.schucha...@canonical.com> wrote:
On 1/9/23 21:31, Simon Glass wrote:
Hi Mark,
On Mon, 9 Jan 2023 at 13:20, Mark Kettenis <mark.kette...@xs4all.nl> wrote:
From: Simon Glass <s...@chromium.org>
Date: Mon, 9 Jan 2023 13:11:01 -0700
Hi Heinrich,
We need to fix how EFI does addresses. It seems to use them as
pointers but store them as u64 ?
That is similar to what you have been doing with physical addresses.
They're defined to a 64-bit unsigned integer by the UEFI
specification, so you can't change it.
I don't mean changing the spec, just changing the internal U-Boot
implementation, which is very confusing. This confusion is spreading
out, too.
Regards,
Simon
The real interesting thing is how memory should be managed in U-Boot:
I would prefer to create a shared global memory management on 4KiB page
level used both for EFI and the rest of U-Boot.
Sounds good.
What EFI adds to the requirements is that you need more than free
(EfiConventionalMemory) and used memory. EFI knows 16 different types of
memory usage (see enum efi_memory_type).
That's a shame. How much of this is legacy and how much is useful?
When loading a file (e.g. with the "load" command) this should lead to a
memory reservation. You should not be able to load a second file into an
overlapping memory area without releasing the allocated memory first.
This would replace lmb which currently tries to recalculate available
memory ab initio again and again.
With managed memory we should be able to get rid of all those constants
like $loadaddr, $fdt_addr_r, $kernel_addr_r, etc. and instead use a
register of named loaded files.
This is where standard boot comes in, since it knows what it has
loaded and has pointers to it.
I see a future where we don't use these commands when we want to save
space. It can save 300KB from the U-Boot size.
But this really has to come later, since there is so much churn already!
For now, please don't add EFI allocation into lmb..that is just odd.
It is not odd but necessary. Without it the Odroid C2 does not boot but
crashes.
It's not Odroid C2, it's anything that with the bad luck to relocate
over the unprotected EFI structures.
So can EFI use the lmb calls to reserve its memory? This patch is backwards.
Simon, the EFI code can manage memory, LMB cannot.
Every time something in U-Boot invokes LMB it recalculates reservations
*ab initio*.
You could use lib/efi_loader/efi_memory to replace LMB but not the other
way round.
We should discard LMB and replace it by proper memory management.
Actually LMB is fine. It is the way it is used in U-Boot, where
subsystems each have their own struct lmb that is the problem.
That is what I meant with 'ab initio'.
LMB cannot replace EFIs memory management because in EFI we have more
memory types than only free and reserved.
Having a limit on the number of memory regions (CONFIG_LMB_MAX_REGIONS
= 8 by default) is also a no-go for EFI.
Best regards
Heinrich
Also note that I'm using LMB in a upcoming patch for the Apple DART
IOMMU to manage device virtual addresses. In that case having a a
separate struct lmb actually makes sense since the device virtual
address spaces are completely separate from eachother and from the
physical address space. So don't remove it just yet ;).