From d4d87596c11d6e3f8220b6d9677797c802af3a33 Mon Sep 17 00:00:00 2001 From: Jian J Wang Date: Mon, 15 Jan 2018 10:16:26 +0800 Subject: [PATCH] UefiCpuPkg/PiSmmCpuDxeSmm: Enable NXE if it's supported If PcdDxeNxMemoryProtectionPolicy is set to enable protection for memory of EfiBootServicesCode, EfiConventionalMemory, the BIOS will hang at a page fault exception triggered by PiSmmCpuDxeSmm. The root cause is that PiSmmCpuDxeSmm will access default SMM RAM starting at 0x30000 which is marked as non-executable, but NX feature was not enabled during SMM initialization. Accessing memory which has invalid attributes set will cause page fault exception. This patch fixes it by checking NX capability in cpuid and enable NXE in EFER MSR if it's available. Cc: Jiewen Yao Cc: Ruiyu Ni Cc: Eric Dong Cc: Laszlo Ersek Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Jian J Wang Reviewed-by: Eric Dong --- UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm | 14 ++++++++++++++ UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm | 12 +++++++++++- 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm index a5c62e77ce..e96dd8d239 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm @@ -42,6 +42,11 @@ ASM_PFX(gcSmiInitGdtr): global ASM_PFX(SmmStartup) ASM_PFX(SmmStartup): + DB 0x66 + mov eax, 0x80000001 ; read capability + cpuid + DB 0x66 + mov ebx, edx ; rdmsr will change edx. keep it in ebx. DB 0x66, 0xb8 ASM_PFX(gSmmCr3): DD 0 mov cr3, eax @@ -50,6 +55,15 @@ ASM_PFX(gSmmCr3): DD 0 DB 0x66, 0xb8 ASM_PFX(gSmmCr4): DD 0 mov cr4, eax + DB 0x66 + mov ecx, 0xc0000080 ; IA32_EFER MSR + rdmsr + DB 0x66 + test ebx, BIT20 ; check NXE capability + jz .1 + or ah, BIT3 ; set NXE bit + wrmsr +.1: DB 0x66, 0xb8 ASM_PFX(gSmmCr0): DD 0 DB 0xbf, PROTECT_MODE_DS, 0 ; mov di, PROTECT_MODE_DS diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm index 2701689c3d..b147e72180 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm @@ -42,6 +42,11 @@ ASM_PFX(gcSmiInitGdtr): global ASM_PFX(SmmStartup) ASM_PFX(SmmStartup): + DB 0x66 + mov eax, 0x80000001 ; read capability + cpuid + DB 0x66 + mov ebx, edx ; rdmsr will change edx. keep it in ebx. DB 0x66, 0xb8 ; mov eax, imm32 ASM_PFX(gSmmCr3): DD 0 mov cr3, rax @@ -54,7 +59,12 @@ ASM_PFX(gSmmCr4): DD 0 DB 0x66 mov ecx, 0xc0000080 ; IA32_EFER MSR rdmsr - or ah, 1 ; set LME bit + or ah, BIT0 ; set LME bit + DB 0x66 + test ebx, BIT20 ; check NXE capability + jz .1 + or ah, BIT3 ; set NXE bit +.1: wrmsr DB 0x66, 0xb8 ; mov eax, imm32 ASM_PFX(gSmmCr0): DD 0 -- 2.39.2