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title "Capture and Restore Context";++;; Copyright (c) 2000 Microsoft Corporation;; Module Name:;; capture.asm;; Abstract:;; This module implements the platform specific code to capture and restore; the context of the caller.;; Author:;; David N. Cutler (davec) 4-Jul-2000;; Environment:;; Any mode.;;--
include ksamd64.inc
altentry RcConsolidateFrames
subttl "Capture Context";++;; VOID; RtlCaptureContext (; IN PCONTEXT ContextRecord; );; Routine Description:;; This function captures the context of the caller in the specified; context record.;; N.B. The stored value of registers rcx and rsp will be a side effect of; having made this call. All other registers will be stored as they; were when the call to this function was made.;; Arguments:;; ContextRecord (rcx) - Supplies a pointer to a context record.;; Return Value:;; None.;;--
CcFrame struct EFlags dd ? ; saved procssor flags Fill dd ? ; fillCcFrame ends
NESTED_ENTRY RtlCaptureContext, _TEXT$00
push_eflags ; save processor flags
END_PROLOGUE
mov CxSegCs[rcx], cs ; save segment registers mov CxSegDs[rcx], ds ; mov CxSegEs[rcx], es ; mov CxSegSs[rcx], ss ; mov CxSegFs[rcx], fs ; mov CxSegGs[rcx], gs ;
mov CxRax[rcx], rax ; save integer registers mov CxRcx[rcx], rcx ; mov CxRdx[rcx], rdx ; mov CxRbx[rcx], rbx ; lea rax, 16[rsp] ; mov CxRsp[rcx], rax ; mov CxRbp[rcx], rbp ; mov CxRsi[rcx], rsi ; mov CxRdi[rcx], rdi ; mov CxR8[rcx], r8 ; mov CxR9[rcx], r9 ; mov CxR10[rcx], r10 ; mov CxR11[rcx], r11 ; mov CxR12[rcx], r12 ; mov CxR13[rcx], r13 ; mov CxR14[rcx], r14 ; mov CxR15[rcx], r15 ;
movdqa CxXmm0[rcx], xmm0 ; save xmm floating registers movdqa CxXmm1[rcx], xmm1 ; movdqa CxXmm2[rcx], xmm2 ; movdqa CxXmm3[rcx], xmm3 ; movdqa CxXmm4[rcx], xmm4 ; movdqa CxXmm5[rcx], xmm5 ; movdqa CxXmm6[rcx], xmm6 ; movdqa CxXmm7[rcx], xmm7 ; movdqa CxXmm8[rcx], xmm8 ; movdqa CxXmm9[rcx], xmm9 ; movdqa CxXmm10[rcx], xmm10 ; movdqa CxXmm11[rcx], xmm11 ; movdqa CxXmm12[rcx], xmm12 ; movdqa CxXmm13[rcx], xmm13 ; movdqa CxXmm14[rcx], xmm14 ; movdqa CxXmm15[rcx], xmm15 ;
stmxcsr CxMxCsr[rcx] ; save xmm floating state
ifndef NTOS_KERNEL_RUNTIME
fnsaved CxFltSave[rcx] ; save legacy floating state
endif
mov rax, 8[rsp] ; set return address mov CxRip[rcx], rax ;
mov eax, Ccframe.EFlags[rsp] ; set processor flags mov CxEFlags[rcx], eax ;
mov dword ptr CxContextFlags[rcx], CONTEXT_FULL ; set context flags add rsp, sizeof CcFrame ; deallocate stack frame ret ; return
NESTED_END RtlCaptureContext, _TEXT$00
subttl "Restore Context";++;; VOID; RtlRestoreContext (; IN PCONTEXT ContextRecord,; IN PEXCEPTION_RECORD ExceptionRecord OPTIONAL; );; Routine Description:;; This function restores the context of the caller to the specified; context.;; Arguments:;; ContextRecord (rcx) - Supplies a pointer to a context record.;; ExceptionRecord (rdx) - Supplies an optional pointer to an exception; record.;; Return Value:;; None - there is no return from this function.;;--
RcFrame struct Mframe db MachineFrameLength dup (?) ; machine frame Fill dq ? ; fill to 0 mod 16RcFrame ends
NESTED_ENTRY RtlRestoreContext, _TEXT$00
push_reg rbp ; save nonvolatile registers push_reg rsi ; push_reg rdi ; alloc_stack (sizeof RcFrame) ; allocate stack frame set_frame rbp, 0 ; set frame pointer
END_PROLOGUE
;; If an exception record is specified and the exception status is the unwind; consolidation code and there is at least one parameter, then consolidate; all the frames that have been unwound and call back to a language specified; routine.;
test rdx, rdx ; test if exception record specified jz Rc10 ; if z, no exception record specified cmp dword ptr ErExceptionCode[rdx], STATUS_UNWIND_CONSOLIDATE ; check call back jne short Rc05 ; if ne, not C++ unwind cmp dword ptr ErNumberParameters[rdx], 1 ; check number parameters jae Rc20 ; if ae, unwind consolidation
;; If an exception record is specified and the exception status is long jump,; then restore the nonvolatile registers to their state at the call to set; jump before restoring the context record.;
Rc05: cmp dword ptr ErExceptionCode[rdx], STATUS_LONGJUMP ; check for long jump jne Rc10 ; if ne, not a long jump
;; Long jump unwind.;; Copy register values from the jump buffer to the context record.;
mov rax, ErExceptionInformation[rdx] ; get jump buffer address mov r8, JbRbx[rax] ; move nonvolatile integer registers mov CxRbx[rcx], r8 ; to context record mov r8, JbRsp[rax] ; mov CxRsp[rcx], r8 ; mov r8, JbRbp[rax] ; mov CxRbp[rcx], r8 ; mov r8, JbRsi[rax] ; mov CxRsi[rcx], r8 ; mov r8, JbRdi[rax] ; mov CxRdi[rcx], r8 ; mov r8, JbR12[rax] ; mov CxR12[rcx], r8 ; mov r8, JbR13[rax] ; mov CxR13[rcx], r8 ; mov r8, JbR14[rax] ; mov CxR14[rcx], r8 ; mov r8, JbR15[rax] ; mov CxR15[rcx], r8 ; mov r8, JbRip[rax] ; mov CxRip[rcx], r8 ;
movdqa xmm0, JbXmm6[rax] ; move nonvolatile floating register movdqa CxXmm6[rcx], xmm0 ; to context record movdqa xmm0, JbXmm7[rax] ; movdqa CxXmm7[rcx], xmm0 ; movdqa xmm0, JbXmm8[rax] ; movdqa CxXmm8[rcx], xmm0 ; movdqa xmm0, JbXmm9[rax] ; movdqa CxXmm9[rcx], xmm0 ; movdqa xmm0, JbXmm10[rax] ; movdqa CxXmm10[rcx], xmm0 ; movdqa xmm0, JbXmm11[rax] ; movdqa CxXmm11[rcx], xmm0 ; movdqa xmm0, JbXmm12[rax] ; movdqa CxXmm12[rcx], xmm0 ; movdqa xmm0, JbXmm13[rax] ; movdqa CxXmm13[rcx], xmm0 ; movdqa xmm0, JbXmm14[rax] ; movdqa CxXmm14[rcx], xmm0 ; movdqa xmm0, JbXmm15[rax] ; movdqa CxXmm15[rcx], xmm0 ;
;; Restore context and continue.;
Rc10: movdqa xmm0, CxXmm0[rcx] ; restore floating registers movdqa xmm1, CxXmm1[rcx] ; movdqa xmm2, CxXmm2[rcx] ; movdqa xmm3, CxXmm3[rcx] ; movdqa xmm4, CxXmm4[rcx] ; movdqa xmm5, CxXmm5[rcx] ; movdqa xmm6, CxXmm6[rcx] ; movdqa xmm7, CxXmm7[rcx] ; movdqa xmm8, CxXmm8[rcx] ; movdqa xmm9, CxXmm9[rcx] ; movdqa xmm10, CxXmm10[rcx] ; movdqa xmm11, CxXmm11[rcx] ; movdqa xmm12, CxXmm12[rcx] ; movdqa xmm13, CxXmm13[rcx] ; movdqa xmm14, CxXmm14[rcx] ; movdqa xmm15, CxXmm15[rcx] ;
ldmxcsr CxMxCsr[rcx] ; restore floating state
mov eax, CxSegSs[rcx] ; set SS segment mov MfSegSs[rsp], eax ; mov rax, CxRsp[rcx] ; set stack address mov MfRsp[rsp], rax ; mov eax, CxEFlags[rcx] ; set processor flags mov MfEFlags[rsp], eax ; mov eax, CxSegCs[rcx] ; set CS segment mov MfSegCs[rsp], eax ; mov rax, CxRip[rcx] ; set return address mov MfRip[rsp], rax ;
mov rax, CxRax[rcx] ; restore volatile integer registers mov rdx, CxRdx[rcx] ; mov r8, CxR8[rcx] ; mov r9, CxR9[rcx] ; mov r10, CxR10[rcx] ; mov r11, CxR11[rcx] ;
ifdef NTOS_KERNEL_RUNTIME
cli ; disable interrupts
endif
mov rbx, CxRbx[rcx] ; restore nonvolatile integer registers mov rsi, CxRsi[rcx] ; mov rdi, CxRdi[rcx] ; mov rbp, CxRbp[rcx] ; mov r12, CxR12[rcx] ; mov r13, CxR13[rcx] ; mov r14, CxR14[rcx] ; mov r15, CxR15[rcx] ; mov rcx, CxRcx[rcx] ; restore integer register iretq ; return
;; Frame consoldation and language specific unwind call back.;
Rc20: sub rsp, MachineFrameLength + 8; allocate machine frame mov r8, rsp ; save machine frame address sub rsp, CONTEXT_FRAME_LENGTH ; allocate context frame mov rsi, rcx ; set source copy address mov rdi, rsp ; set destination copy address mov ecx, CONTEXT_FRAME_LENGTH / 8 ; set length of copy rep movsq ; copy context frame mov rax, CxRsp[rsp] ; set destination stack address in mov MfRsp[r8], rax ; machine frame mov rax, CxRip[rsp] ; set destination address in machine mov MfRip[r8], rax ; frame mov rcx, rdx ; set address of exception record jmp RcConsolidateFrames ; consolidate frames - no return
NESTED_END RtlRestoreContext, _TEXT$00
subttl "Frame Consolidation";++;; Ths following code is never executed. Its purpose is to provide the dummy; prologue necessary to consolidate stack frames for unwind call back processing; at the end of an unwind operation.;;--
NESTED_ENTRY RcFrameConsolidation, _TEXT$00
.pushframe ; .allocstack CONTEXT_FRAME_LENGTH ; allocate stack frame .savereg rbx, CxRbx ; save nonvolatile integer registers .savereg rbp, CxRbp ; .savereg rsi, CxRsi ; .savereg rdi, CxRdi ; .savereg r12, CxR12 ; .savereg r13, CxR13 ; .savereg r14, CxR14 ; .savereg r15, CxR15 ; .savexmm128 xmm6, CxXmm6 ; save nonvolatile floating register .savexmm128 xmm7, CxXmm7 ; .savexmm128 xmm8, CxXmm8 ; .savexmm128 xmm9, CxXmm9 ; .savexmm128 xmm10, CxXmm10 ; .savexmm128 xmm11, CxXmm11 ; .savexmm128 xmm12, CxXmm12 ; .savexmm128 xmm13, CxXmm13 ; .savexmm128 xmm14, CxXmm14 ; .savexmm128 xmm15, CxXmm15 ;
END_PROLOGUE
;++;; VOID; RcConsolidateFrames (; IN PEXCEPTION_RECORD ExceptionRecord; );; Routine Description:;; This routine is called at the end of a unwind operation to logically; remove unwound frames from the stack. This is accomplished by building a; call frame using a machine frame and a context record and then calling; the alternate entry of this function.;; The following code calls the language call back function specified in the; exception record. If the function returns, then the destination frame; context is restored and control transfered to the address returned by the; language call back function. If control does not return, then another; exception must be raised.;; Arguments:;; ExceptionRecord (rdx) - Supplies a pointer to an exception record.;; Implicit Arguments:;; ContextRecord (rsp) - Supplies a pointer to a context record.;; Return Value:;; None.;;--
ALTERNATE_ENTRY RcConsolidateFrames
;; At this point all call frames from the dispatching of the an exception to; a destination language specific handler have been logically unwound and; consolidated into a single large frame.;; The first parameter in the exception record is the address of a callback; routine that performs language specific operations. This routine is called; with the specified exception record as a parameter.;
call qword ptr ErExceptionInformation[rcx] ; call back to handler
;; Restore context and continue.;
mov rcx, rsp ; set address of context record mov CxRip[rcx], rax ; set destination address movdqa xmm0, CxXmm0[rcx] ; restore floating registers movdqa xmm1, CxXmm1[rcx] ; movdqa xmm2, CxXmm2[rcx] ; movdqa xmm3, CxXmm3[rcx] ; movdqa xmm4, CxXmm4[rcx] ; movdqa xmm5, CxXmm5[rcx] ; movdqa xmm6, CxXmm6[rcx] ; movdqa xmm7, CxXmm7[rcx] ; movdqa xmm8, CxXmm8[rcx] ; movdqa xmm9, CxXmm9[rcx] ; movdqa xmm10, CxXmm10[rcx] ; movdqa xmm11, CxXmm11[rcx] ; movdqa xmm12, CxXmm12[rcx] ; movdqa xmm13, CxXmm13[rcx] ; movdqa xmm14, CxXmm14[rcx] ; movdqa xmm15, CxXmm15[rcx] ;
ldmxcsr CxMxCsr[rcx] ; restore floating state
;; Contruct a machine frame of the stack using information from the context; record.;; N.B. The machine frame overlays the parameter area in the context record.;
mov eax, CxSegSs[rcx] ; set SS segment mov MfSegSs[rsp], eax ; mov rax, CxRsp[rcx] ; set stack address mov MfRsp[rsp], rax ; mov eax, CxEFlags[rcx] ; set processor flags mov MfEFlags[rsp], eax ; mov eax, CxSegCs[rcx] ; set CS segment mov MfSegCs[rsp], eax ; mov rax, CxRip[rcx] ; set return address mov MfRip[rsp], rax ;
mov rax, CxRax[rcx] ; restore volatile integer registers mov rdx, CxRdx[rcx] ; mov r8, CxR8[rcx] ; mov r9, CxR9[rcx] ; mov r10, CxR10[rcx] ; mov r11, CxR11[rcx] ;
ifdef NTOS_KERNEL_RUNTIME
cli ; disable interrupts
endif
mov rbx, CxRbx[rcx] ; restore nonvolatile integer registers mov rsi, CxRsi[rcx] ; mov rdi, CxRdi[rcx] ; mov rbp, CxRbp[rcx] ; mov r12, CxR12[rcx] ; mov r13, CxR13[rcx] ; mov r14, CxR14[rcx] ; mov r15, CxR15[rcx] ; mov rcx, CxRcx[rcx] ; restore integer register iretq ; return
NESTED_END RcFrameConsolidation, _TEXT$00
end
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