mirror of https://github.com/acidanthera/audk.git
480 lines
17 KiB
NASM
480 lines
17 KiB
NASM
;/** @file
|
|
; Low leve IA32 specific debug support functions.
|
|
;
|
|
; Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR>
|
|
; SPDX-License-Identifier: BSD-2-Clause-Patent
|
|
;
|
|
;**/
|
|
|
|
%define EXCPT32_DIVIDE_ERROR 0
|
|
%define EXCPT32_DEBUG 1
|
|
%define EXCPT32_NMI 2
|
|
%define EXCPT32_BREAKPOINT 3
|
|
%define EXCPT32_OVERFLOW 4
|
|
%define EXCPT32_BOUND 5
|
|
%define EXCPT32_INVALID_OPCODE 6
|
|
%define EXCPT32_DOUBLE_FAULT 8
|
|
%define EXCPT32_INVALID_TSS 10
|
|
%define EXCPT32_SEG_NOT_PRESENT 11
|
|
%define EXCPT32_STACK_FAULT 12
|
|
%define EXCPT32_GP_FAULT 13
|
|
%define EXCPT32_PAGE_FAULT 14
|
|
%define EXCPT32_FP_ERROR 16
|
|
%define EXCPT32_ALIGNMENT_CHECK 17
|
|
%define EXCPT32_MACHINE_CHECK 18
|
|
%define EXCPT32_SIMD 19
|
|
|
|
%define FXSTOR_FLAG 0x1000000 ; bit cpuid 24 of feature flags
|
|
|
|
SECTION .data
|
|
|
|
global ASM_PFX(OrigVector)
|
|
global ASM_PFX(InterruptEntryStub)
|
|
global ASM_PFX(StubSize)
|
|
global ASM_PFX(CommonIdtEntry)
|
|
global ASM_PFX(FxStorSupport)
|
|
extern ASM_PFX(InterruptDistrubutionHub)
|
|
|
|
ASM_PFX(StubSize): dd InterruptEntryStubEnd - ASM_PFX(InterruptEntryStub)
|
|
AppEsp: dd 0x11111111 ; ?
|
|
DebugEsp: dd 0x22222222 ; ?
|
|
ExtraPush: dd 0x33333333 ; ?
|
|
ExceptData: dd 0x44444444 ; ?
|
|
Eflags: dd 0x55555555 ; ?
|
|
ASM_PFX(OrigVector): dd 0x66666666 ; ?
|
|
|
|
;; The declarations below define the memory region that will be used for the debug stack.
|
|
;; The context record will be built by pushing register values onto this stack.
|
|
;; It is imparitive that alignment be carefully managed, since the FXSTOR and
|
|
;; FXRSTOR instructions will GP fault if their memory operand is not 16 byte aligned.
|
|
;;
|
|
;; The stub will switch stacks from the application stack to the debuger stack
|
|
;; and pushes the exception number.
|
|
;;
|
|
;; Then we building the context record on the stack. Since the stack grows down,
|
|
;; we push the fields of the context record from the back to the front. There
|
|
;; are 132 bytes of stack used prior allocating the 512 bytes of stack to be
|
|
;; used as the memory buffer for the fxstor instruction. Therefore address of
|
|
;; the buffer used for the FXSTOR instruction is &Eax - 132 - 512, which
|
|
;; must be 16 byte aligned.
|
|
;;
|
|
;; We carefully locate the stack to make this happen.
|
|
;;
|
|
;; For reference, the context structure looks like this:
|
|
;; struct {
|
|
;; UINT32 ExceptionData;
|
|
;; FX_SAVE_STATE_IA32 FxSaveState; // 512 bytes, must be 16 byte aligned
|
|
;; UINT32 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
|
|
;; UINT32 Cr0, Cr1, Cr2, Cr3, Cr4;
|
|
;; UINT32 EFlags;
|
|
;; UINT32 Ldtr, Tr;
|
|
;; UINT32 Gdtr[2], Idtr[2];
|
|
;; UINT32 Eip;
|
|
;; UINT32 Gs, Fs, Es, Ds, Cs, Ss;
|
|
;; UINT32 Edi, Esi, Ebp, Esp, Ebx, Edx, Ecx, Eax;
|
|
;; } SYSTEM_CONTEXT_IA32; // 32 bit system context record
|
|
|
|
align 16
|
|
DebugStackEnd: db "DbgStkEnd >>>>>>" ;; 16 byte long string - must be 16 bytes to preserve alignment
|
|
times 0x1ffc dd 0x0 ;; 32K should be enough stack
|
|
;; This allocation is coocked to insure
|
|
;; that the the buffer for the FXSTORE instruction
|
|
;; will be 16 byte aligned also.
|
|
;;
|
|
ExceptionNumber: dd 0 ;; first entry will be the vector number pushed by the stub
|
|
|
|
DebugStackBegin: db "<<<< DbgStkBegin" ;; initial debug ESP == DebugStackBegin, set in stub
|
|
|
|
SECTION .text
|
|
|
|
;------------------------------------------------------------------------------
|
|
; BOOLEAN
|
|
; FxStorSupport (
|
|
; void
|
|
; )
|
|
;
|
|
; Abstract: Returns TRUE if FxStor instructions are supported
|
|
;
|
|
global ASM_PFX(FxStorSupport)
|
|
ASM_PFX(FxStorSupport):
|
|
|
|
;
|
|
; cpuid corrupts ebx which must be preserved per the C calling convention
|
|
;
|
|
push ebx
|
|
mov eax, 1
|
|
cpuid
|
|
mov eax, edx
|
|
and eax, FXSTOR_FLAG
|
|
shr eax, 24
|
|
pop ebx
|
|
ret
|
|
|
|
;------------------------------------------------------------------------------
|
|
; void
|
|
; Vect2Desc (
|
|
; DESCRIPTOR * DestDesc,
|
|
; void (*Vector) (void)
|
|
; )
|
|
;
|
|
; Abstract: Encodes an IDT descriptor with the given physical address
|
|
;
|
|
global ASM_PFX(Vect2Desc)
|
|
ASM_PFX(Vect2Desc):
|
|
push ebp
|
|
mov ebp, esp
|
|
mov eax, [ebp + 0xC]
|
|
mov ecx, [ebp + 0x8]
|
|
mov word [ecx], ax ; write bits 15..0 of offset
|
|
mov dx, cs
|
|
mov word [ecx+2], dx ; SYS_CODE_SEL from GDT
|
|
mov word [ecx+4], 0xe00 | 0x8000 ; type = 386 interrupt gate, present
|
|
shr eax, 16
|
|
mov word [ecx+6], ax ; write bits 31..16 of offset
|
|
leave
|
|
ret
|
|
|
|
;------------------------------------------------------------------------------
|
|
; InterruptEntryStub
|
|
;
|
|
; Abstract: This code is not a function, but is a small piece of code that is
|
|
; copied and fixed up once for each IDT entry that is hooked.
|
|
;
|
|
ASM_PFX(InterruptEntryStub):
|
|
mov [AppEsp], esp ; save stack top
|
|
mov esp, DebugStackBegin ; switch to debugger stack
|
|
push 0 ; push vector number - will be modified before installed
|
|
db 0xe9 ; jump rel32
|
|
dd 0 ; fixed up to relative address of CommonIdtEntry
|
|
InterruptEntryStubEnd:
|
|
|
|
;------------------------------------------------------------------------------
|
|
; CommonIdtEntry
|
|
;
|
|
; Abstract: This code is not a function, but is the common part for all IDT
|
|
; vectors.
|
|
;
|
|
ASM_PFX(CommonIdtEntry):
|
|
;;
|
|
;; At this point, the stub has saved the current application stack esp into AppEsp
|
|
;; and switched stacks to the debug stack, where it pushed the vector number
|
|
;;
|
|
;; The application stack looks like this:
|
|
;;
|
|
;; ...
|
|
;; (last application stack entry)
|
|
;; eflags from interrupted task
|
|
;; CS from interrupted task
|
|
;; EIP from interrupted task
|
|
;; Error code <-------------------- Only present for some exeption types
|
|
;;
|
|
;;
|
|
|
|
;; The stub switched us to the debug stack and pushed the interrupt number.
|
|
;;
|
|
;; Next, construct the context record. It will be build on the debug stack by
|
|
;; pushing the registers in the correct order so as to create the context structure
|
|
;; on the debug stack. The context record must be built from the end back to the
|
|
;; beginning because the stack grows down...
|
|
;
|
|
;; For reference, the context record looks like this:
|
|
;;
|
|
;; typedef
|
|
;; struct {
|
|
;; UINT32 ExceptionData;
|
|
;; FX_SAVE_STATE_IA32 FxSaveState;
|
|
;; UINT32 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
|
|
;; UINT32 Cr0, Cr2, Cr3, Cr4;
|
|
;; UINT32 EFlags;
|
|
;; UINT32 Ldtr, Tr;
|
|
;; UINT32 Gdtr[2], Idtr[2];
|
|
;; UINT32 Eip;
|
|
;; UINT32 Gs, Fs, Es, Ds, Cs, Ss;
|
|
;; UINT32 Edi, Esi, Ebp, Esp, Ebx, Edx, Ecx, Eax;
|
|
;; } SYSTEM_CONTEXT_IA32; // 32 bit system context record
|
|
|
|
;; UINT32 Edi, Esi, Ebp, Esp, Ebx, Edx, Ecx, Eax;
|
|
pushad
|
|
|
|
;; Save interrupt state eflags register...
|
|
pushfd
|
|
pop eax
|
|
mov [Eflags], eax
|
|
|
|
;; We need to determine if any extra data was pushed by the exception, and if so, save it
|
|
;; To do this, we check the exception number pushed by the stub, and cache the
|
|
;; result in a variable since we'll need this again.
|
|
cmp dword [ExceptionNumber], EXCPT32_DOUBLE_FAULT
|
|
jz ExtraPushOne
|
|
cmp dword [ExceptionNumber], EXCPT32_INVALID_TSS
|
|
jz ExtraPushOne
|
|
cmp dword [ExceptionNumber], EXCPT32_SEG_NOT_PRESENT
|
|
jz ExtraPushOne
|
|
cmp dword [ExceptionNumber], EXCPT32_STACK_FAULT
|
|
jz ExtraPushOne
|
|
cmp dword [ExceptionNumber], EXCPT32_GP_FAULT
|
|
jz ExtraPushOne
|
|
cmp dword [ExceptionNumber], EXCPT32_PAGE_FAULT
|
|
jz ExtraPushOne
|
|
cmp dword [ExceptionNumber], EXCPT32_ALIGNMENT_CHECK
|
|
jz ExtraPushOne
|
|
mov dword [ExtraPush], 0
|
|
mov dword [ExceptData], 0
|
|
jmp ExtraPushDone
|
|
|
|
ExtraPushOne:
|
|
mov dword [ExtraPush], 1
|
|
|
|
;; If there's some extra data, save it also, and modify the saved AppEsp to effectively
|
|
;; pop this value off the application's stack.
|
|
mov eax, [AppEsp]
|
|
mov ebx, [eax]
|
|
mov [ExceptData], ebx
|
|
add eax, 4
|
|
mov [AppEsp], eax
|
|
|
|
ExtraPushDone:
|
|
|
|
;; The "pushad" above pushed the debug stack esp. Since what we're actually doing
|
|
;; is building the context record on the debug stack, we need to save the pushed
|
|
;; debug ESP, and replace it with the application's last stack entry...
|
|
mov eax, [esp + 12]
|
|
mov [DebugEsp], eax
|
|
mov eax, [AppEsp]
|
|
add eax, 12
|
|
; application stack has eflags, cs, & eip, so
|
|
; last actual application stack entry is
|
|
; 12 bytes into the application stack.
|
|
mov [esp + 12], eax
|
|
|
|
;; continue building context record
|
|
;; UINT32 Gs, Fs, Es, Ds, Cs, Ss; insure high 16 bits of each is zero
|
|
mov eax, ss
|
|
push eax
|
|
|
|
; CS from application is one entry back in application stack
|
|
mov eax, [AppEsp]
|
|
movzx eax, word [eax + 4]
|
|
push eax
|
|
|
|
mov eax, ds
|
|
push eax
|
|
mov eax, es
|
|
push eax
|
|
mov eax, fs
|
|
push eax
|
|
mov eax, gs
|
|
push eax
|
|
|
|
;; UINT32 Eip;
|
|
; Eip from application is on top of application stack
|
|
mov eax, [AppEsp]
|
|
push dword [eax]
|
|
|
|
;; UINT32 Gdtr[2], Idtr[2];
|
|
push 0
|
|
push 0
|
|
sidt [esp]
|
|
push 0
|
|
push 0
|
|
sgdt [esp]
|
|
|
|
;; UINT32 Ldtr, Tr;
|
|
xor eax, eax
|
|
str ax
|
|
push eax
|
|
sldt ax
|
|
push eax
|
|
|
|
;; UINT32 EFlags;
|
|
;; Eflags from application is two entries back in application stack
|
|
mov eax, [AppEsp]
|
|
push dword [eax + 8]
|
|
|
|
;; UINT32 Cr0, Cr1, Cr2, Cr3, Cr4;
|
|
;; insure FXSAVE/FXRSTOR is enabled in CR4...
|
|
;; ... while we're at it, make sure DE is also enabled...
|
|
mov eax, cr4
|
|
or eax, 0x208
|
|
mov cr4, eax
|
|
push eax
|
|
mov eax, cr3
|
|
push eax
|
|
mov eax, cr2
|
|
push eax
|
|
push 0
|
|
mov eax, cr0
|
|
push eax
|
|
|
|
;; UINT32 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
|
|
mov eax, dr7
|
|
push eax
|
|
;; clear Dr7 while executing debugger itself
|
|
xor eax, eax
|
|
mov dr7, eax
|
|
|
|
mov eax, dr6
|
|
push eax
|
|
;; insure all status bits in dr6 are clear...
|
|
xor eax, eax
|
|
mov dr6, eax
|
|
|
|
mov eax, dr3
|
|
push eax
|
|
mov eax, dr2
|
|
push eax
|
|
mov eax, dr1
|
|
push eax
|
|
mov eax, dr0
|
|
push eax
|
|
|
|
;; FX_SAVE_STATE_IA32 FxSaveState;
|
|
sub esp, 512
|
|
mov edi, esp
|
|
; IMPORTANT!! The debug stack has been carefully constructed to
|
|
; insure that esp and edi are 16 byte aligned when we get here.
|
|
; They MUST be. If they are not, a GP fault will occur.
|
|
fxsave [edi]
|
|
|
|
;; UEFI calling convention for IA32 requires that Direction flag in EFLAGs is clear
|
|
cld
|
|
|
|
;; UINT32 ExceptionData;
|
|
mov eax, [ExceptData]
|
|
push eax
|
|
|
|
; call to C code which will in turn call registered handler
|
|
; pass in the vector number
|
|
mov eax, esp
|
|
push eax
|
|
mov eax, [ExceptionNumber]
|
|
push eax
|
|
call ASM_PFX(InterruptDistrubutionHub)
|
|
add esp, 8
|
|
|
|
; restore context...
|
|
;; UINT32 ExceptionData;
|
|
add esp, 4
|
|
|
|
;; FX_SAVE_STATE_IA32 FxSaveState;
|
|
mov esi, esp
|
|
fxrstor [esi]
|
|
add esp, 512
|
|
|
|
;; UINT32 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
|
|
pop eax
|
|
mov dr0, eax
|
|
pop eax
|
|
mov dr1, eax
|
|
pop eax
|
|
mov dr2, eax
|
|
pop eax
|
|
mov dr3, eax
|
|
;; skip restore of dr6. We cleared dr6 during the context save.
|
|
add esp, 4
|
|
pop eax
|
|
mov dr7, eax
|
|
|
|
;; UINT32 Cr0, Cr1, Cr2, Cr3, Cr4;
|
|
pop eax
|
|
mov cr0, eax
|
|
add esp, 4
|
|
pop eax
|
|
mov cr2, eax
|
|
pop eax
|
|
mov cr3, eax
|
|
pop eax
|
|
mov cr4, eax
|
|
|
|
;; UINT32 EFlags;
|
|
mov eax, [AppEsp]
|
|
pop dword [eax + 8]
|
|
|
|
;; UINT32 Ldtr, Tr;
|
|
;; UINT32 Gdtr[2], Idtr[2];
|
|
;; Best not let anyone mess with these particular registers...
|
|
add esp, 24
|
|
|
|
;; UINT32 Eip;
|
|
pop dword [eax]
|
|
|
|
;; UINT32 SegGs, SegFs, SegEs, SegDs, SegCs, SegSs;
|
|
;; NOTE - modified segment registers could hang the debugger... We
|
|
;; could attempt to insulate ourselves against this possibility,
|
|
;; but that poses risks as well.
|
|
;;
|
|
|
|
pop gs
|
|
pop fs
|
|
pop es
|
|
pop ds
|
|
pop dword [eax + 4]
|
|
pop ss
|
|
|
|
;; The next stuff to restore is the general purpose registers that were pushed
|
|
;; using the "pushad" instruction.
|
|
;;
|
|
;; The value of ESP as stored in the context record is the application ESP
|
|
;; including the 3 entries on the application stack caused by the exception
|
|
;; itself. It may have been modified by the debug agent, so we need to
|
|
;; determine if we need to relocate the application stack.
|
|
|
|
mov ebx, [esp + 12] ; move the potentially modified AppEsp into ebx
|
|
mov eax, [AppEsp]
|
|
add eax, 12
|
|
cmp ebx, eax
|
|
je NoAppStackMove
|
|
|
|
mov eax, [AppEsp]
|
|
mov ecx, [eax] ; EIP
|
|
mov [ebx], ecx
|
|
|
|
mov ecx, [eax + 4] ; CS
|
|
mov [ebx + 4], ecx
|
|
|
|
mov ecx, [eax + 8] ; EFLAGS
|
|
mov [ebx + 8], ecx
|
|
|
|
mov eax, ebx ; modify the saved AppEsp to the new AppEsp
|
|
mov [AppEsp], eax
|
|
NoAppStackMove:
|
|
mov eax, [DebugEsp] ; restore the DebugEsp on the debug stack
|
|
; so our "popad" will not cause a stack switch
|
|
mov [esp + 12], eax
|
|
|
|
cmp dword [ExceptionNumber], 0x68
|
|
jne NoChain
|
|
|
|
Chain:
|
|
|
|
;; Restore eflags so when we chain, the flags will be exactly as if we were never here.
|
|
;; We gin up the stack to do an iretd so we can get ALL the flags.
|
|
mov eax, [AppEsp]
|
|
mov ebx, [eax + 8]
|
|
and ebx, ~ 0x300 ; special handling for IF and TF
|
|
push ebx
|
|
push cs
|
|
push PhonyIretd
|
|
iretd
|
|
PhonyIretd:
|
|
|
|
;; UINT32 Edi, Esi, Ebp, Esp, Ebx, Edx, Ecx, Eax;
|
|
popad
|
|
|
|
;; Switch back to application stack
|
|
mov esp, [AppEsp]
|
|
|
|
;; Jump to original handler
|
|
jmp [ASM_PFX(OrigVector)]
|
|
|
|
NoChain:
|
|
;; UINT32 Edi, Esi, Ebp, Esp, Ebx, Edx, Ecx, Eax;
|
|
popad
|
|
|
|
;; Switch back to application stack
|
|
mov esp, [AppEsp]
|
|
|
|
;; We're outa here...
|
|
iretd
|
|
|