Thanks for the feedback. Please see my comments below. > -----Original Message----- > From: Zeng, Star > Sent: Thursday, September 28, 2017 11:35 AM > To: Wang, Jian J <[email protected]>; [email protected] > Cc: Dong, Eric <[email protected]>; Laszlo Ersek <[email protected]>; Yao, > Jiewen <[email protected]>; Kinney, Michael D > <[email protected]>; Justen, Jordan L <[email protected]>; > Wolman, Ayellet <[email protected]>; Zeng, Star <[email protected]> > Subject: RE: [PATCH v3 3/6] MdeModulePkg/Core/Dxe: Add EndOfDxe > workaround > > Some comments to this patch. > > 1. How about using lower TPL TPL_CALLBACK instead of TPL_NOTIFY for the > notification?
I think it's safe to use TPL_CALLBACK. > 2. Should GCD SetMemorySpaceCapabilities + SetMemorySpaceAttributes be > used instead of gCpu->SetMemoryAttributes()? Yes. Since the GCG out-of-sync issue has been fixed, GCD service should be used instead. > > Thanks, > Star > -----Original Message----- > From: Wang, Jian J > Sent: Thursday, September 28, 2017 9:04 AM > To: [email protected] > Cc: Zeng, Star <[email protected]>; Dong, Eric <[email protected]>; Laszlo > Ersek <[email protected]>; Yao, Jiewen <[email protected]>; Kinney, > Michael D <[email protected]>; Justen, Jordan L > <[email protected]>; Wolman, Ayellet <[email protected]> > Subject: [PATCH v3 3/6] MdeModulePkg/Core/Dxe: Add EndOfDxe workaround > > One of issue caused by enabling NULL pointer detection is that some PCI device > OptionROM, binary drivers and binary OS boot loaders may have NULL pointer > access bugs, which will prevent BIOS from booting and is almost impossible to > fix. BIT7 of PCD PcdNullPointerDetectionPropertyMask is used as a workaround > to indicate BIOS to disable NULL pointer detection right after event > gEfiEndOfDxeEventGroupGuid, and then let boot continue. > > Cc: Star Zeng <[email protected]> > Cc: Eric Dong <[email protected]> > Cc: Laszlo Ersek <[email protected]> > Cc: Jiewen Yao <[email protected]> > Cc: Michael Kinney <[email protected]> > Cc: Jordan Justen <[email protected]> > Cc: Ayellet Wolman <[email protected]> > Suggested-by: Ayellet Wolman <[email protected]> > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Jian J Wang <[email protected]> > --- > MdeModulePkg/Core/Dxe/DxeMain.inf | 1 + > MdeModulePkg/Core/Dxe/Mem/Page.c | 4 ++- > MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 48 > +++++++++++++++++++++++++++ > 3 files changed, 52 insertions(+), 1 deletion(-) > > diff --git a/MdeModulePkg/Core/Dxe/DxeMain.inf > b/MdeModulePkg/Core/Dxe/DxeMain.inf > index 30d5984f7c..0a161ffd71 100644 > --- a/MdeModulePkg/Core/Dxe/DxeMain.inf > +++ b/MdeModulePkg/Core/Dxe/DxeMain.inf > @@ -192,6 +192,7 @@ > gEfiMdeModulePkgTokenSpaceGuid.PcdPropertiesTableEnable > ## > CONSUMES > gEfiMdeModulePkgTokenSpaceGuid.PcdImageProtectionPolicy > ## > CONSUMES > gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy > ## CONSUMES > + gEfiMdeModulePkgTokenSpaceGuid.PcdNullPointerDetectionPropertyMask > ## CONSUMES > > # [Hob] > # RESOURCE_DESCRIPTOR ## CONSUMES > diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c > b/MdeModulePkg/Core/Dxe/Mem/Page.c > index a142c79ee2..0468df3171 100644 > --- a/MdeModulePkg/Core/Dxe/Mem/Page.c > +++ b/MdeModulePkg/Core/Dxe/Mem/Page.c > @@ -188,7 +188,9 @@ CoreAddRange ( > // used for other purposes. > // > if (Type == EfiConventionalMemory && Start == 0 && (End >= EFI_PAGE_SIZE - > 1)) { > - SetMem ((VOID *)(UINTN)Start, EFI_PAGE_SIZE, 0); > + if ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & BIT0) == 0) { > + SetMem ((VOID *)(UINTN)Start, EFI_PAGE_SIZE, 0); > + } > } > > // > diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c > b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c > index a73c4ccd64..73e3b269f3 100644 > --- a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c > +++ b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c > @@ -995,6 +995,36 @@ MemoryProtectionExitBootServicesCallback ( > } > } > > +/** > + Disable NULL pointer detection after EndOfDxe. This is a workaround > +resort in > + order to skip unfixable NULL pointer access issues detected in > +OptionROM or > + boot loaders. > + > + @param[in] Event The Event this notify function registered to. > + @param[in] Context Pointer to the context data registered to the Event. > +**/ > +VOID > +EFIAPI > +DisableNullDetectionAtTheEndOfDxe ( > + EFI_EVENT Event, > + VOID *Context > + ) > +{ > + EFI_STATUS Status; > + > + DEBUG ((DEBUG_INFO, "DisableNullDetectionAtTheEndOfDxe(): > + start\r\n")); // // Disable NULL pointer detection by enabling first > + 4K page // Status = gCpu->SetMemoryAttributes (gCpu, 0, > + EFI_PAGE_SIZE, 0); ASSERT_EFI_ERROR (Status); > + > + CoreCloseEvent (Event); > + DEBUG ((DEBUG_INFO, "DisableNullDetectionAtTheEndOfDxe(): end\r\n")); > + > + return; > +} > + > /** > Initialize Memory Protection support. > **/ > @@ -1006,6 +1036,7 @@ CoreInitializeMemoryProtection ( { > EFI_STATUS Status; > EFI_EVENT Event; > + EFI_EVENT EndOfDxeEvent; > VOID *Registration; > > mImageProtectionPolicy = PcdGet32(PcdImageProtectionPolicy); > @@ -1044,6 +1075,23 @@ CoreInitializeMemoryProtection ( > ); > ASSERT_EFI_ERROR(Status); > } > + > + // > + // Register a callback to disable NULL pointer detection at EndOfDxe > + // if ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & (BIT0|BIT7)) > + == (BIT0|BIT7)) { > + Status = CoreCreateEventEx ( > + EVT_NOTIFY_SIGNAL, > + TPL_NOTIFY, > + DisableNullDetectionAtTheEndOfDxe, > + NULL, > + &gEfiEndOfDxeEventGroupGuid, > + &EndOfDxeEvent > + ); > + ASSERT_EFI_ERROR (Status); > + } > + > return ; > } > > -- > 2.14.1.windows.1 _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
