[PATCH 00/13] efi: Tidy up confusion between pointers and addresses

[Mark Kettenis]

> From: Simon Glass <sjg at chromium.org>
> Date: Wed, 27 Nov 2024 06:08:10 -0700

Hi Simon,

> Hi Tom,
> 
> On Tue, 26 Nov 2024 at 09:08, Tom Rini <trini at konsulko.com> wrote:
> >
> > On Tue, Nov 26, 2024 at 08:39:05AM -0700, Simon Glass wrote:
> > > Hi Heinrich,
> > >
> > > On Tue, 26 Nov 2024 at 02:10, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> > > >
> > > > On 25.11.24 21:44, Simon Glass wrote:
> > > > > The EFI-loader implementation converts things back and forth between
> > > > > addresses and pointers, with not much consistency in how this is done.
> > > > >
> > > > > Within most of U-Boot a pointer is a void * and an address is a ulong
> > > >
> > > > No. It is phys_addr_t that was introduced to handle the sandbox's
> > > > virtual addresses.
> > > >
> > > > And we should keep this sandbox stuff out of the EFI code. They are only
> > > > needed for the command line interface.
> > >
> > > No. My statement is correct and long predates sandbox. U-Boot has
> > > always used ulong. Using an address is generally much easier than a
> > > pointer, so I believe this design decision was (and remains) a good
> > > one. I certainly would not support changing it. The phys_addr_t type
> > > has nothing to do with sandbox.
> >
> > At the high level, I think parts of the problem are that when U-Boot
> > went from 32bit architectures to 36bit architectures (assorted PowerPC
> > Freescale parts) to 64bit architectures that no, we didn't make some
> > concious and consistent statement that "ulong is for address (except
> > when it's not). If you look at the linux kernel, phys_addr_t is physical
> > addresses, ulong is virtual addresses.
> >
> > And so phys_addr_t was introduced, iirc, for PowerPC where we had a
> > 32bit architecture with 36bit addresses and had to deal with that.
> 
> OK, thanks.
> 
> I'm a bit unsure what to do here...but am leaning towards having a
> separate struct for the memory areas in struct efi_mem_list, rather
> than using the same efi_mem_desc. Then I can have one use addresses
> and the other pointers.

That does not make sense to me.  Why would you want to use pointers to
manage what is effectively a memory address map?