From 5267926134d17e86672b84fd57b438f05ffa68e1 Mon Sep 17 00:00:00 2001 From: Jian J Wang Date: Tue, 25 Sep 2018 16:49:19 +0800 Subject: [PATCH] MdeModulePkg/DxeIpl: support more NX related PCDs 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 Cc: Laszlo Ersek Cc: Ard Biesheuvel Cc: Ruiyu Ni Cc: Jiewen Yao Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Jian J Wang Reviewed-by: Star Zeng Reviewed-by: Laszlo Ersek --- MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf | 2 + .../Core/DxeIplPeim/Ia32/DxeLoadFunc.c | 35 +---------- .../Core/DxeIplPeim/X64/VirtualMemory.c | 61 ++++++++++++++++++- .../Core/DxeIplPeim/X64/VirtualMemory.h | 12 ++++ 4 files changed, 76 insertions(+), 34 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..0bf99bc77e 100644 --- a/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c +++ b/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c @@ -186,37 +186,6 @@ IsIa32PaeSupport ( return Ia32PaeSupport; } -/** - 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 - ) -{ - UINT32 RegEax; - UINT32 RegEdx; - BOOLEAN Available; - - Available = FALSE; - AsmCpuid (0x80000000, &RegEax, NULL, NULL, NULL); - if (RegEax >= 0x80000001) { - AsmCpuid (0x80000001, NULL, NULL, NULL, &RegEdx); - if ((RegEdx & BIT20) != 0) { - // - // Bit 20: Execute Disable Bit available. - // - Available = TRUE; - } - } - - return Available; -} - /** The function will check if page table should be setup or not. @@ -245,7 +214,7 @@ ToBuildPageTable ( return TRUE; } - if (PcdGetBool (PcdSetNxForStack) && IsExecuteDisableBitAvailable ()) { + if (IsEnableNonExecNeeded ()) { return TRUE; } @@ -436,7 +405,7 @@ HandOffToDxeCore ( BuildPageTablesIa32Pae = ToBuildPageTable (); if (BuildPageTablesIa32Pae) { PageTables = Create4GPageTablesIa32Pae (BaseOfStack, STACK_SIZE); - if (IsExecuteDisableBitAvailable ()) { + if (IsEnableNonExecNeeded ()) { EnableExecuteDisableBit(); } } diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c index 496e219913..cf3c3f94d8 100644 --- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c +++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c @@ -106,6 +106,62 @@ IsNullDetectionEnabled ( return ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & BIT0) != 0); } +/** + 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 + ) +{ + UINT32 RegEax; + UINT32 RegEdx; + BOOLEAN Available; + + Available = FALSE; + AsmCpuid (0x80000000, &RegEax, NULL, NULL, NULL); + if (RegEax >= 0x80000001) { + AsmCpuid (0x80000001, NULL, NULL, NULL, &RegEdx); + if ((RegEdx & BIT20) != 0) { + // + // Bit 20: Execute Disable Bit available. + // + Available = TRUE; + } + } + + return Available; +} + +/** + 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 +IsEnableNonExecNeeded ( + 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 +811,10 @@ CreateIdentityMappingPageTables ( // EnablePageTableProtection ((UINTN)PageMap, TRUE); - if (PcdGetBool (PcdSetNxForStack)) { + // + // Set IA32_EFER.NXE if necessary. + // + if (IsEnableNonExecNeeded ()) { EnableExecuteDisableBit (); } diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h index 85457ff937..8ae92d3bf6 100644 --- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h +++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h @@ -179,6 +179,18 @@ 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 +IsEnableNonExecNeeded ( + VOID + ); + /** Enable Execute Disable Bit.