Re: [PATCH] ArmPkg/ArmMmuLib ARM: trim high memory regions instead of rejecting them

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On Mon, 28 Jan 2019 at 19:11, Leif Lindholm <leif.lindholm@linaro.org> wrote:
>
> On Mon, Jan 28, 2019 at 05:23:32PM +0100, Ard Biesheuvel wrote:
> > ArmSetMemoryAttributes() still chokes in some cases, i.e., when the
> > length of the region exceeds 4 GB, the subtraction overflows, which
> > results in the region being misidentified as being 32-bit addressable.
> >
> > Let's update the logic to trim the length to what we can address with
> > 32 bits. This fixes the issue, and also deals with the issue where an
> > entire region is disregarded if part of it exceeds beyond what we can
> > map with 32 bits.
> >
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>
> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
>

Thanks

Pushed as 9a00a7164a39..66509f90fc66

> > ---
> >  ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c
> > index bffab83d4fd0..baa085c3849a 100644
> > --- a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c
> > +++ b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c
> > @@ -744,10 +744,11 @@ ArmSetMemoryAttributes (
> >    UINT64        ChunkLength;
> >    BOOLEAN       FlushTlbs;
> >
> > -  if (BaseAddress > (UINT64)MAX_ADDRESS - Length + 1) {
> > +  if (BaseAddress > (UINT64)MAX_ADDRESS) {
> >      return EFI_UNSUPPORTED;
> >    }
> >
> > +  Length = MIN (Length, (UINT64)MAX_ADDRESS - BaseAddress + 1);
> >    if (Length == 0) {
> >      return EFI_SUCCESS;
> >    }
> > --
> > 2.20.1
> >