DxeCore will only apply EFI_MEMORY_RO to image CODE memory (controlled by
PcdImageProtectionPolicy). Normally allocated rt_code/bs_code memory won't be
marked as read-only. So my answer is NO.
Regards,
Jian
> -----Original Message-----
> From: Ni, Ruiyu
> Sent: Thursday, March 15, 2018 2:56 PM
> To: Wang, Jian J <jian.j.w...@intel.com>; edk2-devel@lists.01.org
> Cc: Yao, Jiewen <jiewen....@intel.com>; Dong, Eric <eric.d...@intel.com>;
> Zeng, Star <star.z...@intel.com>
> Subject: Re: [edk2] [PATCH] MdeModulePkg/PiSmmCore: fix #PF caused by
> freeing read-only memory
>
> On 3/15/2018 2:22 PM, Jian J Wang wrote:
> > SMM core will add a HEADER before each allocated pool memory and clean
> > up this header once it's freed. If a block of allocated pool is marked
> > as read-only after allocation (EfiRuntimeServicesCode type of pool in
> > SMM will always be marked as read-only), #PF exception will be triggered
> > during memory pool freeing.
> >
> > Normally EfiRuntimeServicesCode type of pool should not be freed in the
> > real world. But some test suites will actually do memory free for all
> > types of memory for the purpose of functionality and conformance test.
> > So this issue should be fixed anyway.
>
> Does DxeCore have such problem?
>
> >
> > Cc: Star Zeng <star.z...@intel.com>
> > Cc: Eric Dong <eric.d...@intel.com>
> > Cc: Jiewen Yao <jiewen....@intel.com>
> > Cc: Ruiyu Ni <ruiyu...@intel.com>
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Jian J Wang <jian.j.w...@intel.com>
> > ---
> > MdeModulePkg/Core/PiSmmCore/HeapGuard.c | 22
> ++++++++++++++++++++++
> > 1 file changed, 22 insertions(+)
> >
> > diff --git a/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
> b/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
> > index f9657f9baa..d5556eb79c 100644
> > --- a/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
> > +++ b/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
> > @@ -941,6 +941,7 @@ AdjustMemoryF (
> > EFI_PHYSICAL_ADDRESS MemoryToTest;
> > UINTN PagesToFree;
> > UINT64 GuardBitmap;
> > + UINT64 Attributes;
> >
> > if (Memory == NULL || NumberOfPages == NULL || *NumberOfPages == 0)
> {
> > return;
> > @@ -949,6 +950,27 @@ AdjustMemoryF (
> > Start = *Memory;
> > PagesToFree = *NumberOfPages;
> >
> > + //
> > + // In case the memory to free is marked as read-only (e.g.
> EfiRuntimeServicesCode).
> > + //
> > + if (mSmmMemoryAttribute != NULL) {
> > + Attributes = 0;
> > + mSmmMemoryAttribute->GetMemoryAttributes (
> > + mSmmMemoryAttribute,
> > + Start,
> > + EFI_PAGES_TO_SIZE (PagesToFree),
> > + &Attributes
> > + );
> > + if ((Attributes & EFI_MEMORY_RO) != 0) {
> > + mSmmMemoryAttribute->ClearMemoryAttributes (
> > + mSmmMemoryAttribute,
> > + Start,
> > + EFI_PAGES_TO_SIZE (PagesToFree),
> > + EFI_MEMORY_RO
> > + );
> > + }
> > + }
> > +
> > //
> > // Head Guard must be one page before, if any.
> > //
> >
>
>
> --
> Thanks,
> Ray
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