diff options
3 files changed, 12 insertions, 3 deletions
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionHandlerAsm.nasm b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionHandlerAsm.nasm index 45d6474091..6fcf5fb23f 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionHandlerAsm.nasm +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionHandlerAsm.nasm @@ -383,6 +383,13 @@ ErrorCodeAndVectorOnStack: pop dword [ebp - 4]
mov esp, ebp
pop ebp
+
+; Enable TF bit after page fault handler runs
+ cmp dword [esp], 14 ; #PF?
+ jne .5
+ bts dword [esp + 16], 8 ; EFLAGS
+
+.5:
add esp, 8
cmp dword [esp - 16], 0 ; check EXCEPTION_HANDLER_CONTEXT.OldIdtHandler
jz DoReturn
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionTssEntryAsm.nasm b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionTssEntryAsm.nasm index 62bcedea1a..7aac29c7e7 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionTssEntryAsm.nasm +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ExceptionTssEntryAsm.nasm @@ -355,10 +355,8 @@ o16 mov [ecx + IA32_TSS._SS], ax movzx ebx, word [ecx + IA32_TSS._CS]
mov [eax - 0x8], ebx ; create CS in old stack
mov ebx, dword [ecx + IA32_TSS.EFLAGS]
- bts ebx, 8
+ bts ebx, 8 ; Set TF
mov [eax - 0x4], ebx ; create eflags in old stack
- mov dword [ecx + IA32_TSS.EFLAGS], ebx ; update eflags in old TSS
- mov eax, dword [ecx + IA32_TSS._ESP] ; Get old stack pointer
sub eax, 0xc ; minus 12 byte
mov dword [ecx + IA32_TSS._ESP], eax ; Set new stack pointer
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm index 7b97810d10..f842af2336 100644 --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm @@ -336,6 +336,10 @@ HasErrorCode: pop r15
mov rsp, rbp
+ cmp qword [rbp + 8], 14 ; #PF?
+ jne .1
+ bts qword [rsp + 40], 8 ; RFLAGS.TF
+.1:
pop rbp
add rsp, 16
cmp qword [rsp - 32], 0 ; check EXCEPTION_HANDLER_CONTEXT.OldIdtHandler
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