As I remember UEFI 2.5 clarified this and added EFI_MEMORY_RO was because EFI_MEMORY_WP had been typically used for cache even before UEFI 2.5.
And I do not think this patch should filter out EFI_MEMORY_WP since this patch is to filter out new paging bits caused by 14dde9e903bb9a719ebb8f3381da72b19509bc36 [MdeModulePkg/Core: Fix out-of-sync issue in GCD]. Thanks, Star -----Original Message----- From: Ard Biesheuvel [mailto:ard.biesheu...@linaro.org] Sent: Thursday, November 16, 2017 5:30 PM To: Zeng, Star <star.z...@intel.com> Cc: Wang, Jian J <jian.j.w...@intel.com>; Laszlo Ersek <ler...@redhat.com>; edk2-devel@lists.01.org; Yao, Jiewen <jiewen....@intel.com> Subject: Re: [edk2] [PATCH v6 1/2] MdeModulePkg/DxeCore: Filter out all paging capabilities On 16 November 2017 at 09:28, Zeng, Star <star.z...@intel.com> wrote: > Ard, > > EFI_MEMORY_WP is for cache. > > UefiSpec.h > // > // Note: UEFI spec 2.5 and following: use EFI_MEMORY_RO as > write-protected physical memory // protection attribute. Also, EFI_MEMORY_WP > means cacheability attribute. > // > #define EFI_MEMORY_WP 0x0000000000001000ULL > Yes, but that was a change in v2.5, before that it was a permission attribute. So it should be filtered from the OS visible memory map as well. > Thanks, > Star > -----Original Message----- > From: Ard Biesheuvel [mailto:ard.biesheu...@linaro.org] > Sent: Thursday, November 16, 2017 5:25 PM > To: Wang, Jian J <jian.j.w...@intel.com> > Cc: edk2-devel@lists.01.org; Yao, Jiewen <jiewen....@intel.com>; Zeng, > Star <star.z...@intel.com>; Laszlo Ersek <ler...@redhat.com> > Subject: Re: [PATCH v6 1/2] MdeModulePkg/DxeCore: Filter out all > paging capabilities > > On 16 November 2017 at 07:26, Jian J Wang <jian.j.w...@intel.com> wrote: >> Some OSs will treat EFI_MEMORY_DESCRIPTOR.Attribute as really set >> attributes and change memory paging attribute accordingly. >> But current EFI_MEMORY_DESCRIPTOR.Attribute is assigned by value from >> Capabilities in GCD memory map. This might cause boot problems. >> Clearing all paging related capabilities can workaround it. The code >> added in this patch is supposed to be removed once the usage of >> EFI_MEMORY_DESCRIPTOR.Attribute is clarified in UEFI spec and adopted >> by both EDK-II Core and all supported OSs. >> >> Cc: Jiewen Yao <jiewen....@intel.com> >> Cc: Star Zeng <star.z...@intel.com> >> Cc: Laszlo Ersek <ler...@redhat.com> >> Cc: Ard Biesheuvel <ard.biesheu...@linaro.org> >> Contributed-under: TianoCore Contribution Agreement 1.1 >> Signed-off-by: Jian J Wang <jian.j.w...@intel.com> >> --- >> MdeModulePkg/Core/Dxe/Mem/Page.c | 17 +++++++++++++++++ >> 1 file changed, 17 insertions(+) >> >> diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c >> b/MdeModulePkg/Core/Dxe/Mem/Page.c >> index c9219cc068..783b576e35 100644 >> --- a/MdeModulePkg/Core/Dxe/Mem/Page.c >> +++ b/MdeModulePkg/Core/Dxe/Mem/Page.c >> @@ -1829,6 +1829,23 @@ CoreGetMemoryMap ( >> // >> BufferSize = ((UINT8 *)MemoryMap - (UINT8 *)MemoryMapStart); >> >> + // >> + // WORKAROUND: Some OSs will treat EFI_MEMORY_DESCRIPTOR.Attribute as >> really >> + // set attributes and change memory paging attribute >> accordingly. >> + // But current EFI_MEMORY_DESCRIPTOR.Attribute is assigned by >> + // value from Capabilities in GCD memory map. This might cause >> + // boot problems. Clearing all paging related capabilities can >> + // workaround it. Following code is supposed to be removed >> once >> + // the usage of EFI_MEMORY_DESCRIPTOR.Attribute is clarified >> in >> + // UEFI spec and adopted by both EDK-II Core and all supported >> + // OSs. >> + // >> + while (MemoryMapStart < MemoryMap) { >> + MemoryMapStart->Attribute &= ~(UINT64)(EFI_MEMORY_RP | EFI_MEMORY_RO | >> + EFI_MEMORY_XP); > > Why is EFI_MEMORY_WP missing here? > >> + MemoryMapStart = NEXT_MEMORY_DESCRIPTOR(MemoryMapStart, Size); >> + } >> + >> Status = EFI_SUCCESS; >> >> Done: >> -- >> 2.14.1.windows.1 >> > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
