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34576c7015
This is used in KiUserModeCallout instead of KiServiceExit2. The latter is broken, leaks non-volatile registers and will need to be modified to handle an exception frame, which we don't need/have here. It will also use sysret instead of iret and is generally simpler/faster. Eventually it would be desirable to skip the entire trap frame setup and do everything in KiCallUserMode. This requires some cleanup and special handling for user APC delivery.
152 lines
3 KiB
ArmAsm
152 lines
3 KiB
ArmAsm
/*
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* PROJECT: ReactOS Kernel
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* LICENSE: GPL-2.0+ (https://spdx.org/licenses/GPL-2.0+)
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* PURPOSE: ReactOS AMD64 user mode callback helper
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* COPYRIGHT: Timo Kreuzer (timo.kreuzer@reactos.org)
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*/
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#include <ksamd64.inc>
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#include <trapamd64.inc>
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EXTERN KiInitiateUserApc:PROC
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EXTERN KeUserCallbackDispatcher:QWORD
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/*
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* NTSTATUS
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* KiUserModeCallout (
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* _Inout_ PKCALLOUT_FRAME CalloutFrame);
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*/
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EXTERN KiUserModeCallout:PROC
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.code64
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/*
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* NTSTATUS
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* KiCallUserMode (
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* _In_ PVOID *OutputBuffer@<rcx>,
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* _In_ PULONG OutputLength@<rdx>);
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*/
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PUBLIC KiCallUserMode
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.PROC KiCallUserMode
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/* Generate a KEXCEPTION_FRAME on the stack */
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/* This is identical to a KCALLOUT_FRAME */
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GENERATE_EXCEPTION_FRAME
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/* Save OutputBuffer and OutputLength */
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mov [rsp + ExOutputBuffer], rcx
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mov [rsp + ExOutputLength], rdx
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/* Call the C function */
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mov rcx, rsp
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call KiUserModeCallout
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/* Restore the registers from the KEXCEPTION_FRAME */
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RESTORE_EXCEPTION_STATE
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/* Return */
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ret
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.ENDP
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/*!
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* \brief Exits to user mode, restores only rsp and rip, zeroes the rest.
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*
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* \todo Merge this with KiCallUserMode + KiUserModeCallout and skip the trap frame.
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*
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* DECLSPEC_NORETURN
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* VOID
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* KiUserCallbackExit(
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* _In_ PKTRAP_FRAME TrapFrame@<rcx>);
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*/
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PUBLIC KiUserCallbackExit
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KiUserCallbackExit:
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/* Point rsp to the trap frame */
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mov rsp, rcx
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/* Zero non-volatile registers for KiUserCallbackDispatcher.
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This must be done before dispatching a pending user APC. */
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xor rbx, rbx
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xor rdi, rdi
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xor rsi, rsi
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xor rbp, rbp
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xor r12, r12
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xor r13, r13
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xor r14, r14
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xor r15, r15
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pxor xmm6, xmm6
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pxor xmm7, xmm7
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pxor xmm8, xmm8
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pxor xmm9, xmm9
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pxor xmm10, xmm10
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pxor xmm11, xmm11
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pxor xmm12, xmm12
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pxor xmm13, xmm13
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pxor xmm14, xmm14
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pxor xmm15, xmm15
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/* Check for pending user APC */
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mov rdx, gs:[PcCurrentThread]
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HANDLE_USER_APCS rdx, rsp
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/* Zero volatile registers */
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xor rax, rax
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xor rdx, rdx
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xor r8, r8
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xor r9, r9
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xor r10, r10
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pxor xmm0, xmm0
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pxor xmm1, xmm1
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pxor xmm2, xmm2
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pxor xmm3, xmm3
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pxor xmm4, xmm4
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pxor xmm5, xmm5
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/* Disable interrupts for return */
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cli
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/* Prepare user mode return address (rcx) and eflags (r11) for sysret */
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mov rcx, qword ptr KeUserCallbackDispatcher[rip]
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mov r11, EFLAGS_IF_MASK
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/* Load user mode stack (It was copied to the trap frame) */
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mov rsp, [rsp + KTRAP_FRAME_Rsp]
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/* Swap gs back to user */
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swapgs
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/* return to user mode */
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sysretq
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/*
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* DECLSPEC_NORETURN
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* VOID
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* KiCallbackReturn (
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* _In_ PVOID Stack,
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* _In_ NTSTATUS Status);
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*/
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PUBLIC KiCallbackReturn
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.PROC KiCallbackReturn
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.ENDPROLOG
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/* Restore the stack */
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mov rsp, rcx
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/* Set return status */
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mov eax, edx
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/* Restore the registers from the KEXCEPTION_FRAME */
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RESTORE_EXCEPTION_STATE
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/* Return */
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ret
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.ENDP
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END
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