> v2 changes: > a. remove macros no longer needed > b. remove DEBUG and ASSERT in ToEnableExecuteDisableFeature() > c. change ToEnableExecuteDisableFeature to EnableNonExec
BZ#1116: https://bugzilla.tianocore.org/show_bug.cgi?id=1116 Currently IA32_EFER.NXE is only set against PcdSetNxForStack. This confuses developers because following two other PCDs also need NXE to be set, but actually not. PcdDxeNxMemoryProtectionPolicy PcdImageProtectionPolicy This patch solves this issue by adding logic to enable IA32_EFER.NXE if any of those PCDs have anything enabled. Cc: Star Zeng <[email protected]> Cc: Laszlo Ersek <[email protected]> Cc: Ard Biesheuvel <[email protected]> Cc: Ruiyu Ni <[email protected]> Cc: Jiewen Yao <[email protected]> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Jian J Wang <[email protected]> --- MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf | 2 ++ MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c | 4 ++-- MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c | 30 +++++++++++++++++++++++- MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h | 24 +++++++++++++++++++ 4 files changed, 57 insertions(+), 3 deletions(-) diff --git a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf index fd82657404..068e700074 100644 --- a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf +++ b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf @@ -117,6 +117,8 @@ [Pcd.IA32,Pcd.X64,Pcd.ARM,Pcd.AARCH64] gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack ## SOMETIMES_CONSUMES + gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy ## SOMETIMES_CONSUMES + gEfiMdeModulePkgTokenSpaceGuid.PcdImageProtectionPolicy ## SOMETIMES_CONSUMES [Depex] gEfiPeiLoadFilePpiGuid AND gEfiPeiMasterBootModePpiGuid diff --git a/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c b/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c index d28baa3615..ccd30f964b 100644 --- a/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c +++ b/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c @@ -245,7 +245,7 @@ ToBuildPageTable ( return TRUE; } - if (PcdGetBool (PcdSetNxForStack) && IsExecuteDisableBitAvailable ()) { + if (EnableNonExec ()) { return TRUE; } @@ -436,7 +436,7 @@ HandOffToDxeCore ( BuildPageTablesIa32Pae = ToBuildPageTable (); if (BuildPageTablesIa32Pae) { PageTables = Create4GPageTablesIa32Pae (BaseOfStack, STACK_SIZE); - if (IsExecuteDisableBitAvailable ()) { + if (EnableNonExec ()) { EnableExecuteDisableBit(); } } diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c index 496e219913..73b0f67c6b 100644 --- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c +++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c @@ -106,6 +106,31 @@ IsNullDetectionEnabled ( return ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & BIT0) != 0); } +/** + Check if Execute Disable Bit (IA32_EFER.NXE) should be enabled or not. + + @retval TRUE IA32_EFER.NXE should be enabled. + @retval FALSE IA32_EFER.NXE should not be enabled. + +**/ +BOOLEAN +EnableNonExec ( + VOID + ) +{ + if (!IsExecuteDisableBitAvailable ()) { + return FALSE; + } + + // + // XD flag (BIT63) in page table entry is only valid if IA32_EFER.NXE is set. + // Features controlled by Following PCDs need this feature to be enabled. + // + return (PcdGetBool (PcdSetNxForStack) || + PcdGet64 (PcdDxeNxMemoryProtectionPolicy) != 0 || + PcdGet32 (PcdImageProtectionPolicy) != 0); +} + /** Enable Execute Disable Bit. @@ -755,7 +780,10 @@ CreateIdentityMappingPageTables ( // EnablePageTableProtection ((UINTN)PageMap, TRUE); - if (PcdGetBool (PcdSetNxForStack)) { + // + // Set IA32_EFER.NXE if necessary. + // + if (EnableNonExec ()) { EnableExecuteDisableBit (); } diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h index 85457ff937..09085312aa 100644 --- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h +++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h @@ -179,6 +179,30 @@ typedef struct { UINTN FreePages; } PAGE_TABLE_POOL; +/** + Check if Execute Disable Bit (IA32_EFER.NXE) should be enabled or not. + + @retval TRUE IA32_EFER.NXE should be enabled. + @retval FALSE IA32_EFER.NXE should not be enabled. + +**/ +BOOLEAN +EnableNonExec ( + VOID + ); + +/** + The function will check if Execute Disable Bit is available. + + @retval TRUE Execute Disable Bit is available. + @retval FALSE Execute Disable Bit is not available. + +**/ +BOOLEAN +IsExecuteDisableBitAvailable ( + VOID + ); + /** Enable Execute Disable Bit. -- 2.16.2.windows.1 _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
