diff options
Diffstat (limited to 'MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.S')
-rw-r--r-- | MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.S | 1095 |
1 files changed, 548 insertions, 547 deletions
diff --git a/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.S b/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.S index 597d3dced7..0cc502ab7a 100644 --- a/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.S +++ b/MdeModulePkg/Universal/DebugSupportDxe/X64/AsmFuncs.S @@ -1,547 +1,548 @@ -#/**@file
-# Low leve x64 specific debug support functions.
-#
-# Copyright (c) 2006 - 2009, Intel Corporation
-# All rights reserved. This program and the accompanying materials
-# are licensed and made available under the terms and conditions of the BSD License
-# which accompanies this distribution. The full text of the license may be found at
-# http://opensource.org/licenses/bsd-license.php
-#
-# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
-# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
-#
-#**/
-
-ASM_GLOBAL ASM_PFX(OrigVector)
-ASM_GLOBAL ASM_PFX(InterruptEntryStub)
-ASM_GLOBAL ASM_PFX(StubSize)
-ASM_GLOBAL ASM_PFX(CommonIdtEntry)
-ASM_GLOBAL ASM_PFX(FxStorSupport)
-
-.data
-
-ASM_PFX(StubSize): .long ASM_PFX(InterruptEntryStubEnd) - ASM_PFX(InterruptEntryStub)
-ASM_PFX(AppRsp): .long 0x11111111 # ?
- .long 0x11111111 # ?
-ASM_PFX(DebugRsp): .long 0x22222222 # ?
- .long 0x22222222 # ?
-ASM_PFX(ExtraPush): .long 0x33333333 # ?
- .long 0x33333333 # ?
-ASM_PFX(ExceptData): .long 0x44444444 # ?
- .long 0x44444444 # ?
-ASM_PFX(Rflags): .long 0x55555555 # ?
- .long 0x55555555 # ?
-ASM_PFX(OrigVector): .long 0x66666666 # ?
- .long 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 336 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 - 336 - 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 {
-## UINT64 ExceptionData;
-## FX_SAVE_STATE_X64 FxSaveState; // 512 bytes, must be 16 byte aligned
-## UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
-## UINT64 Cr0, Cr1, Cr2, Cr3, Cr4, Cr8;
-## UINT64 RFlags;
-## UINT64 Ldtr, Tr;
-## UINT64 Gdtr[2], Idtr[2];
-## UINT64 Rip;
-## UINT64 Gs, Fs, Es, Ds, Cs, Ss;
-## UINT64 Rdi, Rsi, Rbp, Rsp, Rbx, Rdx, Rcx, Rax;
-## UINT64 R8, R9, R10, R11, R12, R13, R14, R15;
-## } SYSTEM_CONTEXT_X64; // 64 bit system context record
-
-.p2align 4
-DebugStackEnd : .ascii "DbgStkEnd >>>>>>" # 16 byte long string - must be 16 bytes to preserve alignment
- .fill 0x1ffc, 4, 0x00000000
- # 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.
- #
-ASM_PFX(ExceptionNumber): .long 0x77777777 # first entry will be the vector number pushed by the stub
- .long 0x77777777 # ?
-
-DebugStackBegin : .ascii "<<<< DbgStkBegin" # initial debug ESP == DebugStackBegin, set in stub
-
-
-.text
-
-#------------------------------------------------------------------------------
-# BOOLEAN
-# FxStorSupport (
-# void
-# )
-#
-# Abstract: Returns TRUE if FxStor instructions are supported
-#
-ASM_GLOBAL ASM_PFX(FxStorSupport)
-ASM_PFX(FxStorSupport):
-#
-# cpuid corrupts rbx which must be preserved per the C calling convention
-#
- pushq %rbx
- movq $1, %rax
- cpuid
- movl %edx, %eax
- andq $0x01000000, %rax
- shrq $24, %rax
- popq %rbx
- ret
-#------------------------------------------------------------------------------
-# void
-# Vect2Desc (
-# IA32_IDT_GATE_DESCRIPTOR * DestDesc, // rcx
-# void (*Vector) (void) // rdx
-# )
-#
-# Abstract: Encodes an IDT descriptor with the given physical address
-#
-ASM_GLOBAL ASM_PFX(Vect2Desc)
-ASM_PFX(Vect2Desc):
- movq %rdx, %rax
- movw %ax, (%rcx) # write bits 15..0 of offset
- movw %cs, %dx
- movw %dx, 2(%rcx) # SYS_CODE_SEL from GDT
- movw $(0x0e00 | 0x8000), 4(%rcx) # type = 386 interrupt gate, present
- shrq $16, %rax
- movw %ax, 6(%rcx) # write bits 31..16 of offset
- shrq $16, %rax
- movl %eax, 8(%rcx) # write bits 63..32 of offset
-
- 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_GLOBAL ASM_PFX(InterruptEntryStub)
-ASM_PFX(InterruptEntryStub):
-
- pushq $0 # push vector number - will be modified before installed
- jmp ASM_PFX(CommonIdtEntry)
-
-ASM_GLOBAL ASM_PFX(InterruptEntryStubEnd)
-ASM_PFX(InterruptEntryStubEnd):
-
-#------------------------------------------------------------------------------
-# CommonIdtEntry
-#
-# Abstract: This code is not a function, but is the common part for all IDT
-# vectors.
-#
-ASM_GLOBAL ASM_PFX(CommonIdtEntry)
-##
-## At this point, the stub has saved the current application stack esp into AppRsp
-## and switched stacks to the debug stack, where it pushed the vector number
-##
-## The application stack looks like this:
-##
-## ...
-## (last application stack entry)
-## [16 bytes alignment, do not care it]
-## SS from interrupted task
-## RSP from interrupted task
-## rflags from interrupted task
-## CS from interrupted task
-## RIP from interrupted task
-## Error code <-------------------- Only present for some exeption types
-##
-## Vector Number <----------------- pushed in our IDT Entry
-##
-
-
-## 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 {
-## UINT64 ExceptionData;
-## FX_SAVE_STATE_X64 FxSaveState;
-## UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
-## UINT64 Cr0, Cr2, Cr3, Cr4, Cr8;
-## UINT64 RFlags;
-## UINT64 Ldtr, Tr;
-## UINT64 Gdtr[2], Idtr[2];
-## UINT64 Rip;
-## UINT64 Gs, Fs, Es, Ds, Cs, Ss;
-## UINT64 Rdi, Rsi, Rbp, Rsp, Rbx, Rdx, Rcx, Rax;
-## UINT64 R8, R9, R10, R11, R12, R13, R14, R15;
-## } SYSTEM_CONTEXT_X64; // 64
-ASM_PFX(CommonIdtEntry):
-## NOTE: we save rsp here to prevent compiler put rip reference cause error AppRsp
- pushq %rax
- movq (8)(%rsp), %rax # save vector number
- movq %rax, ASM_PFX(ExceptionNumber) # save vector number
- popq %rax
- addq $8, %rsp # pop vector number
- movq %rsp, ASM_PFX(AppRsp) # save stack top
- movq DebugStackBegin, %rsp # switch to debugger stack
- subq $8, %rsp # leave space for vector number
-## UINT64 Rdi, Rsi, Rbp, Rsp, Rbx, Rdx, Rcx, Rax;
-## UINT64 R8, R9, R10, R11, R12, R13, R14, R15;
- pushq %r15
- pushq %r14
- pushq %r13
- pushq %r12
- pushq %r11
- pushq %r10
- pushq %r9
- pushq %r8
- pushq %rax
- pushq %rcx
- pushq %rdx
- pushq %rbx
- pushq %rsp
- pushq %rbp
- pushq %rsi
- pushq %rdi
-## Save interrupt state rflags register...
- pushfq
- popq %rax
- movq %rax, ASM_PFX(Rflags)
-## 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.
- cmpl $0, ASM_PFX(ExceptionNumber)
- jz ExtraPushOne
- cmpl $10, ASM_PFX(ExceptionNumber)
- jz ExtraPushOne
- cmpl $11, ASM_PFX(ExceptionNumber)
- jz ExtraPushOne
- cmpl $12, ASM_PFX(ExceptionNumber)
- jz ExtraPushOne
- cmpl $13, ASM_PFX(ExceptionNumber)
- jz ExtraPushOne
- cmpl $14, ASM_PFX(ExceptionNumber)
- jz ExtraPushOne
- cmpl $17, ASM_PFX(ExceptionNumber)
- jz ExtraPushOne
- movl $0, ASM_PFX(ExtraPush)
- movl $0, ASM_PFX(ExceptData)
- jmp ExtraPushDone
-ExtraPushOne:
- movl $1, ASM_PFX(ExtraPush)
-
-## If there's some extra data, save it also, and modify the saved AppRsp to effectively
-## pop this value off the application's stack.
- movq ASM_PFX(AppRsp), %rax
- movq (%rax), %rbx
- movq %rbx, ASM_PFX(ExceptData)
- addq $8, %rax
- movq %rax, ASM_PFX(AppRsp)
-
-ExtraPushDone:
-
-## The "push" above pushed the debug stack rsp. Since what we're actually doing
-## is building the context record on the debug stack, we need to save the pushed
-## debug RSP, and replace it with the application's last stack entry...
- movq 24(%rsp), %rax
- movq %rax, ASM_PFX(DebugRsp)
- movq ASM_PFX(AppRsp), %rax
- addq $40, %rax
- # application stack has ss, rsp, rflags, cs, & rip, so
- # last actual application stack entry is 40 bytes
- # into the application stack.
- movq %rax, 24(%rsp)
-
-## continue building context record
-## UINT64 Gs, Fs, Es, Ds, Cs, Ss; insure high 16 bits of each is zero
- movq %ss, %rax
- pushq %rax
- # CS from application is one entry back in application stack
- movq ASM_PFX(AppRsp), %rax
- movzxw 8(%rax), %rax
- pushq %rax
-
- movq %ds, %rax
- pushq %rax
- movq %es, %rax
- pushq %rax
- movq %fs, %rax
- pushq %rax
- movq %gs, %rax
- pushq %rax
-## UINT64 Rip;
- # Rip from application is on top of application stack
- movq ASM_PFX(AppRsp), %rax
- pushq (%rax)
-## UINT64 Gdtr[2], Idtr[2];
- push $0
- push $0
- sidtq (%rsp)
- push $0
- push $0
- sgdtq (%rsp)
-
-## UINT64 Ldtr, Tr;
- xorq %rax, %rax
- str %ax
- pushq %rax
- sldt %ax
- pushq %rax
-
-## UINT64 RFlags;
-## Rflags from application is two entries back in application stack
- movq ASM_PFX(AppRsp), %rax
- pushq 16(%rax)
-## UINT64 Cr0, Cr1, Cr2, Cr3, Cr4, Cr8;
-## insure FXSAVE/FXRSTOR is enabled in CR4...
-## ... while we're at it, make sure DE is also enabled...
- movq %cr8, %rax
- pushq %rax
- movq %cr4, %rax
- orq $0x208, %rax
- movq %rax, %cr4
- pushq %rax
- movq %cr3, %rax
- pushq %rax
- movq %cr2, %rax
- pushq %rax
- push $0
- movq %cr0, %rax
- pushq %rax
-## UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
- movq %dr7, %rax
- pushq %rax
-## clear Dr7 while executing debugger itself
- xorq %rax, %rax
- movq %rax, %dr7
-
- movq %dr6, %rax
- pushq %rax
-## insure all status bits in dr6 are clear...
- xorq %rax, %rax
- movq %rax, %dr6
-
- movq %dr3, %rax
- pushq %rax
- movq %dr2, %rax
- pushq %rax
- movq %dr1, %rax
- pushq %rax
- movq %dr0, %rax
- pushq %rax
-
-## FX_SAVE_STATE_X64 FxSaveState;
- subq $512, %rsp
- movq %rsp, %rdi
- # IMPORTANT!! The debug stack has been carefully constructed to
- # insure that rsp and rdi are 16 byte aligned when we get here.
- # They MUST be. If they are not, a GP fault will occur.
-
- # FXSTOR_RDI
- fxsave (%rdi)
-
-## UINT64 ExceptionData;
- movq ASM_PFX(ExceptData), %rax
- pushq %rax
-
-# call to C code which will in turn call registered handler
-# pass in the vector number
- movq %rsp, %rdx
- movq ASM_PFX(ExceptionNumber), %rcx
- subq $40, %rsp
- call ASM_PFX(InterruptDistrubutionHub)
- addq $40, %rsp
-# restore context...
-## UINT64 ExceptionData;
- addq $8, %rsp
-
-## FX_SAVE_STATE_X64 FxSaveState;
- movq %rsp, %rsi
-
- # FXRSTOR_RSI
- fxrstor (%rsi)
-
- addq $512, %rsp
-
-## UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7;
- popq %rax
- movq %rax, %dr0
- popq %rax
- movq %rax, %dr1
- popq %rax
- movq %rax, %dr2
- popq %rax
- movq %rax, %dr3
-
-## skip restore of dr6. We cleared dr6 during the context save.
- addq $8, %rsp
- popq %rax
- movq %rax, %dr7
-
-## UINT64 Cr0, Cr1, Cr2, Cr3, Cr4, Cr8;
- popq %rax
- movq %rax, %cr0
- addq $8, %rsp
- popq %rax
- movq %rax, %cr2
- popq %rax
- movq %rax, %cr3
- popq %rax
- movq %rax, %cr4
- popq %rax
- movq %rax, %cr8
-## UINT64 RFlags;
- movq ASM_PFX(AppRsp), %rax
- popq 16(%rax)
-## UINT64 Ldtr, Tr;
-## UINT64 Gdtr[2], Idtr[2];
-## Best not let anyone mess with these particular registers...
- addq $48, %rsp
-## UINT64 Rip;
- popq (%rax)
-
-## UINT64 Gs, Fs, Es, Ds, Cs, Ss;
-## NOTE - modified segment registers could hang the debugger... We
-## could attempt to insulate ourselves against this possibility,
-## but that poses risks as well.
-##
-
- popq %rax
- # movq %rax, %gs
- popq %rax
- # movq %rax, %fs
- popq %rax
- movq %rax, %es
- popq %rax
- movq %rax, %ds
- movq ASM_PFX(AppRsp), %rax
- popq 8(%rax)
- popq %rax
- movq %rax, %ss
-## The next stuff to restore is the general purpose registers that were pushed
-## using the "push" instruction.
-##
-## The value of RSP as stored in the context record is the application RSP
-## including the 5 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.
-
- movq 24(%rsp), %rbx # move the potentially modified AppRsp into rbx
- movq ASM_PFX(AppRsp), %rax
- addq $40, %rax
- cmpq %rax, %rbx
- je NoAppStackMove
-
- movq ASM_PFX(AppRsp), %rax
- movq (%rax), %rcx # RIP
- movq %rcx, (%rbx)
-
- movq 8(%rax), %rcx # CS
- movq %rcx, 8(%rbx)
-
- movq 16(%rax), %rcx # RFLAGS
- movq %rcx, 16(%rbx)
-
- movq 24(%rax), %rcx # RSP
- movq %rcx, 24(%rbx)
-
- movq 32(%rax), %rcx # SS
- movq %rcx, 32(%rbx)
-
- movq %rbx, %rax # modify the saved AppRsp to the new AppRsp
- movq %rax, ASM_PFX(AppRsp)
-NoAppStackMove:
- movq ASM_PFX(DebugRsp), %rax # restore the DebugRsp on the debug stack
- # so our "pop" will not cause a stack switch
- movq %rax, 24(%rsp)
-
- cmpl $0x068, ASM_PFX(ExceptionNumber)
- jne NoChain
-
-Chain:
-
-## Restore rflags so when we chain, the flags will be exactly as if we were never here.
-## We gin up the stack to do an iretq so we can get ALL the flags.
- movq ASM_PFX(AppRsp), %rax
- movq 40(%rax), %rbx
- pushq %rbx
- movq %ss, %rax
- pushq %rax
- movq %rsp, %rax
- addq $16, %rax
- pushq %rax
- movq ASM_PFX(AppRsp), %rax
- movq 16(%rax), %rbx
- andq $0xfffffffffffffcff, %rbx # special handling for IF and TF
- pushq %rbx
- movq %cs, %rax
- pushq %rax
- movq PhonyIretq, %rax
- pushq %rax
- iretq
-PhonyIretq:
-
-## UINT64 Rdi, Rsi, Rbp, Rsp, Rbx, Rdx, Rcx, Rax;
-## UINT64 R8, R9, R10, R11, R12, R13, R14, R15;
- popq %rdi
- popq %rsi
- popq %rbp
- popq %rsp
- popq %rbx
- popq %rdx
- popq %rcx
- popq %rax
- popq %r8
- popq %r9
- popq %r10
- popq %r11
- popq %r12
- popq %r13
- popq %r14
- popq %r15
-
-## Switch back to application stack
- movq ASM_PFX(AppRsp), %rsp
-## Jump to original handler
- jmp ASM_PFX(OrigVector)
-NoChain:
-## UINT64 Rdi, Rsi, Rbp, Rsp, Rbx, Rdx, Rcx, Rax;
-## UINT64 R8, R9, R10, R11, R12, R13, R14, R15;
- popq %rdi
- popq %rsi
- popq %rbp
- popq %rsp
- popq %rbx
- popq %rdx
- popq %rcx
- popq %rax
- popq %r8
- popq %r9
- popq %r10
- popq %r11
- popq %r12
- popq %r13
- popq %r14
- popq %r15
-
-## Switch back to application stack
- movq ASM_PFX(AppRsp), %rsp
-
-## We're outa here...
- iret
+///**@file +// Low leve x64 specific debug support functions. +// +// Copyright (c) 2006 - 2009, Intel Corporation +// Portions copyright (c) 2008-2009 Apple Inc. All rights reserved. +// All rights reserved. This program and the accompanying materials +// are licensed and made available under the terms and conditions of the BSD License +// which accompanies this distribution. The full text of the license may be found at +// http://opensource.org/licenses/bsd-license.php +// +// THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, +// WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. +// +//**/ + +ASM_GLOBAL ASM_PFX(OrigVector) +ASM_GLOBAL ASM_PFX(InterruptEntryStub) +ASM_GLOBAL ASM_PFX(StubSize) +ASM_GLOBAL ASM_PFX(CommonIdtEntry) +ASM_GLOBAL ASM_PFX(FxStorSupport) + +.data + +ASM_PFX(StubSize): .long ASM_PFX(InterruptEntryStubEnd) - ASM_PFX(InterruptEntryStub) +ASM_PFX(AppRsp): .long 0x11111111 # ? + .long 0x11111111 # ? +ASM_PFX(DebugRsp): .long 0x22222222 # ? + .long 0x22222222 # ? +ASM_PFX(ExtraPush): .long 0x33333333 # ? + .long 0x33333333 # ? +ASM_PFX(ExceptData): .long 0x44444444 # ? + .long 0x44444444 # ? +ASM_PFX(Rflags): .long 0x55555555 # ? + .long 0x55555555 # ? +ASM_PFX(OrigVector): .long 0x66666666 # ? + .long 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 336 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 - 336 - 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 { +// UINT64 ExceptionData; +// FX_SAVE_STATE_X64 FxSaveState; // 512 bytes, must be 16 byte aligned +// UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7; +// UINT64 Cr0, Cr1, Cr2, Cr3, Cr4, Cr8; +// UINT64 RFlags; +// UINT64 Ldtr, Tr; +// UINT64 Gdtr[2], Idtr[2]; +// UINT64 Rip; +// UINT64 Gs, Fs, Es, Ds, Cs, Ss; +// UINT64 Rdi, Rsi, Rbp, Rsp, Rbx, Rdx, Rcx, Rax; +// UINT64 R8, R9, R10, R11, R12, R13, R14, R15; +// } SYSTEM_CONTEXT_X64; // 64 bit system context record + +.p2align 4 +DebugStackEnd : .ascii "DbgStkEnd >>>>>>" # 16 byte long string - must be 16 bytes to preserve alignment + .fill 0x1ffc, 4, 0x00000000 + # 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. + # +ASM_PFX(ExceptionNumber): .long 0x77777777 # first entry will be the vector number pushed by the stub + .long 0x77777777 # ? + +DebugStackBegin : .ascii "<<<< DbgStkBegin" # initial debug ESP == DebugStackBegin, set in stub + + +.text + +//------------------------------------------------------------------------------ +// BOOLEAN +// FxStorSupport ( +// void +// ) +// +// Abstract: Returns TRUE if FxStor instructions are supported +// +ASM_GLOBAL ASM_PFX(FxStorSupport) +ASM_PFX(FxStorSupport): +// +// cpuid corrupts rbx which must be preserved per the C calling convention +// + pushq %rbx + movq $1, %rax + cpuid + movl %edx, %eax + andq $0x01000000, %rax + shrq $24, %rax + popq %rbx + ret +//------------------------------------------------------------------------------ +// void +// Vect2Desc ( +// IA32_IDT_GATE_DESCRIPTOR * DestDesc, // rcx +// void (*Vector) (void) // rdx +// ) +// +// Abstract: Encodes an IDT descriptor with the given physical address +// +ASM_GLOBAL ASM_PFX(Vect2Desc) +ASM_PFX(Vect2Desc): + movq %rdx, %rax + movw %ax, (%rcx) # write bits 15..0 of offset + movw %cs, %dx + movw %dx, 2(%rcx) # SYS_CODE_SEL from GDT + movw $(0x0e00 | 0x8000), 4(%rcx) # type = 386 interrupt gate, present + shrq $16, %rax + movw %ax, 6(%rcx) # write bits 31..16 of offset + shrq $16, %rax + movl %eax, 8(%rcx) # write bits 63..32 of offset + + 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_GLOBAL ASM_PFX(InterruptEntryStub) +ASM_PFX(InterruptEntryStub): + + pushq $0 # push vector number - will be modified before installed + jmp ASM_PFX(CommonIdtEntry) + +ASM_GLOBAL ASM_PFX(InterruptEntryStubEnd) +ASM_PFX(InterruptEntryStubEnd): + +//------------------------------------------------------------------------------ +// CommonIdtEntry +// +// Abstract: This code is not a function, but is the common part for all IDT +// vectors. +// +ASM_GLOBAL ASM_PFX(CommonIdtEntry) +// +// At this point, the stub has saved the current application stack esp into AppRsp +// and switched stacks to the debug stack, where it pushed the vector number +// +// The application stack looks like this: +// +// ... +// (last application stack entry) +// [16 bytes alignment, do not care it] +// SS from interrupted task +// RSP from interrupted task +// rflags from interrupted task +// CS from interrupted task +// RIP from interrupted task +// Error code <-------------------- Only present for some exeption types +// +// Vector Number <----------------- pushed in our IDT Entry +// + + +// 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 { +// UINT64 ExceptionData; +// FX_SAVE_STATE_X64 FxSaveState; +// UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7; +// UINT64 Cr0, Cr2, Cr3, Cr4, Cr8; +// UINT64 RFlags; +// UINT64 Ldtr, Tr; +// UINT64 Gdtr[2], Idtr[2]; +// UINT64 Rip; +// UINT64 Gs, Fs, Es, Ds, Cs, Ss; +// UINT64 Rdi, Rsi, Rbp, Rsp, Rbx, Rdx, Rcx, Rax; +// UINT64 R8, R9, R10, R11, R12, R13, R14, R15; +// } SYSTEM_CONTEXT_X64; // 64 +ASM_PFX(CommonIdtEntry): +// NOTE: we save rsp here to prevent compiler put rip reference cause error AppRsp + pushq %rax + movq (8)(%rsp), %rax # save vector number + movq %rax, ASM_PFX(ExceptionNumber)(%rip) # save vector number + popq %rax + addq $8, %rsp # pop vector number + movq %rsp, ASM_PFX(AppRsp)(%rip) # save stack top + movq DebugStackBegin(%rip), %rsp # switch to debugger stack + subq $8, %rsp # leave space for vector number +// UINT64 Rdi, Rsi, Rbp, Rsp, Rbx, Rdx, Rcx, Rax; +// UINT64 R8, R9, R10, R11, R12, R13, R14, R15; + pushq %r15 + pushq %r14 + pushq %r13 + pushq %r12 + pushq %r11 + pushq %r10 + pushq %r9 + pushq %r8 + pushq %rax + pushq %rcx + pushq %rdx + pushq %rbx + pushq %rsp + pushq %rbp + pushq %rsi + pushq %rdi +// Save interrupt state rflags register... + pushfq + popq %rax + movq %rax, ASM_PFX(Rflags)(%rip) +// 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. + cmpl $0, ASM_PFX(ExceptionNumber)(%rip) + jz ExtraPushOne + cmpl $10, ASM_PFX(ExceptionNumber)(%rip) + jz ExtraPushOne + cmpl $11, ASM_PFX(ExceptionNumber)(%rip) + jz ExtraPushOne + cmpl $12, ASM_PFX(ExceptionNumber)(%rip) + jz ExtraPushOne + cmpl $13, ASM_PFX(ExceptionNumber)(%rip) + jz ExtraPushOne + cmpl $14, ASM_PFX(ExceptionNumber)(%rip) + jz ExtraPushOne + cmpl $17, ASM_PFX(ExceptionNumber)(%rip) + jz ExtraPushOne + movl $0, ASM_PFX(ExtraPush)(%rip) + movl $0, ASM_PFX(ExceptData)(%rip) + jmp ExtraPushDone +ExtraPushOne: + movl $1, ASM_PFX(ExtraPush)(%rip) + +// If there's some extra data, save it also, and modify the saved AppRsp to effectively +// pop this value off the application's stack. + movq ASM_PFX(AppRsp)(%rip), %rax + movq (%rax), %rbx + movq %rbx, ASM_PFX(ExceptData)(%rip) + addq $8, %rax + movq %rax, ASM_PFX(AppRsp)(%rip) + +ExtraPushDone: + +// The "push" above pushed the debug stack rsp. Since what we're actually doing +// is building the context record on the debug stack, we need to save the pushed +// debug RSP, and replace it with the application's last stack entry... + movq 24(%rsp), %rax + movq %rax, ASM_PFX(DebugRsp)(%rip) + movq ASM_PFX(AppRsp)(%rip), %rax + addq $40, %rax + # application stack has ss, rsp, rflags, cs, & rip, so + # last actual application stack entry is 40 bytes + # into the application stack. + movq %rax, 24(%rsp) + +// continue building context record +// UINT64 Gs, Fs, Es, Ds, Cs, Ss; insure high 16 bits of each is zero + mov %ss, %rax + pushq %rax + # CS from application is one entry back in application stack + movq ASM_PFX(AppRsp)(%rip), %rax + movzxw 8(%rax), %rax + pushq %rax + + mov %ds, %rax + pushq %rax + movw %es, %rax + pushq %rax + mov %fs, %rax + pushq %rax + mov %gs, %rax + pushq %rax +// UINT64 Rip; + # Rip from application is on top of application stack + movq ASM_PFX(AppRsp)(%rip), %rax + pushq (%rax) +// UINT64 Gdtr[2], Idtr[2]; + push $0 + push $0 + sidtq (%rsp) + push $0 + push $0 + sgdtq (%rsp) + +// UINT64 Ldtr, Tr; + xorq %rax, %rax + str %ax + pushq %rax + sldt %ax + pushq %rax + +// UINT64 RFlags; +// Rflags from application is two entries back in application stack + movq ASM_PFX(AppRsp)(%rip), %rax + pushq 16(%rax) +// UINT64 Cr0, Cr1, Cr2, Cr3, Cr4, Cr8; +// insure FXSAVE/FXRSTOR is enabled in CR4... +// ... while we're at it, make sure DE is also enabled... + movq %cr8, %rax + pushq %rax + movq %cr4, %rax + orq $0x208, %rax + movq %rax, %cr4 + pushq %rax + movq %cr3, %rax + pushq %rax + movq %cr2, %rax + pushq %rax + push $0 + movq %cr0, %rax + pushq %rax +// UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7; + movq %dr7, %rax + pushq %rax +// clear Dr7 while executing debugger itself + xorq %rax, %rax + movq %rax, %dr7 + + movq %dr6, %rax + pushq %rax +// insure all status bits in dr6 are clear... + xorq %rax, %rax + movq %rax, %dr6 + + movq %dr3, %rax + pushq %rax + movq %dr2, %rax + pushq %rax + movq %dr1, %rax + pushq %rax + movq %dr0, %rax + pushq %rax + +// FX_SAVE_STATE_X64 FxSaveState; + subq $512, %rsp + movq %rsp, %rdi + # IMPORTANT!! The debug stack has been carefully constructed to + # insure that rsp and rdi are 16 byte aligned when we get here. + # They MUST be. If they are not, a GP fault will occur. + + # FXSTOR_RDI + fxsave (%rdi) + +// UINT64 ExceptionData; + movq ASM_PFX(ExceptData)(%rip), %rax + pushq %rax + +// call to C code which will in turn call registered handler +// pass in the vector number + movq %rsp, %rdx + movq ASM_PFX(ExceptionNumber)(%rip), %rcx + subq $40, %rsp + call ASM_PFX(InterruptDistrubutionHub) + addq $40, %rsp +// restore context... +// UINT64 ExceptionData; + addq $8, %rsp + +// FX_SAVE_STATE_X64 FxSaveState; + movq %rsp, %rsi + + # FXRSTOR_RSI + fxrstor (%rsi) + + addq $512, %rsp + +// UINT64 Dr0, Dr1, Dr2, Dr3, Dr6, Dr7; + popq %rax + movq %rax, %dr0 + popq %rax + movq %rax, %dr1 + popq %rax + movq %rax, %dr2 + popq %rax + movq %rax, %dr3 + +// skip restore of dr6. We cleared dr6 during the context save. + addq $8, %rsp + popq %rax + movq %rax, %dr7 + +// UINT64 Cr0, Cr1, Cr2, Cr3, Cr4, Cr8; + popq %rax + movq %rax, %cr0 + addq $8, %rsp + popq %rax + movq %rax, %cr2 + popq %rax + movq %rax, %cr3 + popq %rax + movq %rax, %cr4 + popq %rax + movq %rax, %cr8 +// UINT64 RFlags; + movq ASM_PFX(AppRsp)(%rip), %rax + popq 16(%rax) +// UINT64 Ldtr, Tr; +// UINT64 Gdtr[2], Idtr[2]; +// Best not let anyone mess with these particular registers... + addq $48, %rsp +// UINT64 Rip; + popq (%rax) + +// UINT64 Gs, Fs, Es, Ds, Cs, Ss; +// NOTE - modified segment registers could hang the debugger... We +// could attempt to insulate ourselves against this possibility, +// but that poses risks as well. +// + + popq %rax + # mov %rax, %gs + popq %rax + # mov %rax, %fs + popq %rax + mov %rax, %es + popq %rax + mov %rax, %ds + movq ASM_PFX(AppRsp)(%rip), %rax + popq 8(%rax) + popq %rax + mov %rax, %ss +## The next stuff to restore is the general purpose registers that were pushed +## using the "push" instruction. +## +## The value of RSP as stored in the context record is the application RSP +## including the 5 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. + + movq 24(%rsp), %rbx # move the potentially modified AppRsp into rbx + movq ASM_PFX(AppRsp)(%rip), %rax + addq $40, %rax + cmpq %rax, %rbx + je NoAppStackMove + + movq ASM_PFX(AppRsp)(%rip), %rax + movq (%rax), %rcx # RIP + movq %rcx, (%rbx) + + movq 8(%rax), %rcx # CS + movq %rcx, 8(%rbx) + + movq 16(%rax), %rcx # RFLAGS + movq %rcx, 16(%rbx) + + movq 24(%rax), %rcx # RSP + movq %rcx, 24(%rbx) + + movq 32(%rax), %rcx # SS + movq %rcx, 32(%rbx) + + movq %rbx, %rax # modify the saved AppRsp to the new AppRsp + movq %rax, ASM_PFX(AppRsp)(%rip) +NoAppStackMove: + movq ASM_PFX(DebugRsp)(%rip), %rax # restore the DebugRsp on the debug stack + # so our "pop" will not cause a stack switch + movq %rax, 24(%rsp) + + cmpl $0x068, ASM_PFX(ExceptionNumber)(%rip) + jne NoChain + +Chain: + +// Restore rflags so when we chain, the flags will be exactly as if we were never here. +// We gin up the stack to do an iretq so we can get ALL the flags. + movq ASM_PFX(AppRsp)(%rip), %rax + movq 40(%rax), %rbx + pushq %rbx + mov %ss, %rax + pushq %rax + movq %rsp, %rax + addq $16, %rax + pushq %rax + movq ASM_PFX(AppRsp)(%rip), %rax + movq 16(%rax), %rbx + andq $0xfffffffffffffcff, %rbx # special handling for IF and TF + pushq %rbx + mov %cs, %rax + pushq %rax + movq PhonyIretq(%rip), %rax + pushq %rax + iretq +PhonyIretq: + +// UINT64 Rdi, Rsi, Rbp, Rsp, Rbx, Rdx, Rcx, Rax; +// UINT64 R8, R9, R10, R11, R12, R13, R14, R15; + popq %rdi + popq %rsi + popq %rbp + popq %rsp + popq %rbx + popq %rdx + popq %rcx + popq %rax + popq %r8 + popq %r9 + popq %r10 + popq %r11 + popq %r12 + popq %r13 + popq %r14 + popq %r15 + +// Switch back to application stack + movq ASM_PFX(AppRsp)(%rip), %rsp +// Jump to original handler + jmp ASM_PFX(OrigVector) +NoChain: +// UINT64 Rdi, Rsi, Rbp, Rsp, Rbx, Rdx, Rcx, Rax; +// UINT64 R8, R9, R10, R11, R12, R13, R14, R15; + popq %rdi + popq %rsi + popq %rbp + popq %rsp + popq %rbx + popq %rdx + popq %rcx + popq %rax + popq %r8 + popq %r9 + popq %r10 + popq %r11 + popq %r12 + popq %r13 + popq %r14 + popq %r15 + +// Switch back to application stack + movq ASM_PFX(AppRsp)(%rip), %rsp + +// We're outa here... + iret |