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

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

[Ard Biesheuvel]

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>
---
 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

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

[Leif Lindholm]

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>

> ---
>  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
> 

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

[Ard Biesheuvel]

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
> >