On Mon, 2 Mar 2020 at 17:54, Arvind Sankar <nivedita@xxxxxxxxxxxx> wrote:
>
> On Mon, Mar 02, 2020 at 08:49:17AM +0100, Ard Biesheuvel wrote:
> > On Mon, 2 Mar 2020 at 00:04, Arvind Sankar <nivedita@xxxxxxxxxxxx> wrote:
> ...
> > > call 1f
> > > -1: pop %ebp
> > > - subl $1b, %ebp
> > > +1: pop %ebx
> > > + subl $1b, %ebx
> ...
> > >
> > > + movl %ebx, %ebp // startup_32 for efi32_pe_stub_entry
> >
> > The code that follows efi32_pe_stub_entry still expects the runtime
> > displacement in %ebp, so we'll need to pass that in another way here.
> >
> > > jmp efi32_pe_stub_entry
>
> Didn't follow -- what do you mean by runtime displacement?
>
> efi32_pe_stub_entry expects the runtime address of startup_32 to be in
> %ebp, but with the changes for keeping the frame pointer in %ebp, I
> changed the runtime address to be in %ebx instead. Hence I added that
> movl %ebx, %ebp to put it in %ebp just before calling efi32_pe_stub_entry.
> That should be fine, no?
But how does that work with:
SYM_INNER_LABEL(efi32_pe_stub_entry, SYM_L_LOCAL)
movl %ecx, efi32_boot_args(%ebp)
movl %edx, efi32_boot_args+4(%ebp)
movb $0, efi_is64(%ebp)
?
