reactos/ntoskrnl/ke/amd64/ctxswitch.S
Hervé Poussineau ae4ce99e00 [ASM x64] Fix usage of macro .allocstack
.allocstack only accepts one 'size' parameter."
2021-01-28 20:31:16 +01:00

220 lines
5.4 KiB
ArmAsm

/*
* COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS kernel
* FILE: ntoskrnl/ke/amd64/ctxswitch.S
* PURPOSE: Thread Context Switching
*
* PROGRAMMER: Timo kreuzer (timo.kreuzer@reactos.org)
*/
/* INCLUDES ******************************************************************/
#include <ksamd64.inc>
/*
* BOOLEAN
* KiSwapContextResume(
* _In_ KIRQL WaitIrql,
* _In_ PKTHREAD OldThread,
* _In_ PKTHREAD NewThread)
*/
EXTERN KiSwapContextResume:PROC
/* FUNCTIONS ****************************************************************/
.code64
/*!
* \name KiThreadStartup
*
* \brief
* The KiThreadStartup routine is the beginning of any thread.
*
* VOID
* KiThreadStartup(
* IN PKSTART_ROUTINE StartRoutine<rcx>,
* IN PVOID StartContext<rdx>,
* IN PVOID P3<r8>,
* IN PVOID P4<r9>,
* IN PVOID SystemRoutine);
*
* \param StartRoutine
* For Kernel Threads only, specifies the starting execution point
* of the new thread.
*
* \param StartContext
* For Kernel Threads only, specifies a pointer to variable
* context data to be sent to the StartRoutine above.
*
* \param P3, P4 - not used atm
*
* \param SystemRoutine
* Pointer to the System Startup Routine.
* Either PspUserThreadStartup or PspSystemThreadStartup
*
* \return
* Should never return for a system thread. Returns through the System Call
* Exit Dispatcher for a user thread.
*
* \remarks
* If a return from a system thread is detected, a bug check will occur.
*
*--*/
PUBLIC KiThreadStartup
.PROC KiThreadStartup
/* KSTART_FRAME is already on the stack when we enter here.
* The virtual prolog looks like this:
* sub rsp, 5 * 8
* mov [rsp + SfP1Home], rcx
* mov [rsp + SfP2Home], rdx
* mov [rsp + SfP3Home], r8
* mov [rsp + SfP4Home], r9
*/
/* Terminate the unwind chain, by setting rbp as frame pointer,
which contains 0 */
.setframe rbp, 0
.endprolog
/* Clear all the non-volatile registers, so the thread won't be tempted to
* expect any static data (like some badly coded usermode/win9x apps do) */
xor rbx, rbx
xor rsi, rsi
xor rdi, rdi
xor rbp, rbp
xor r10, r10
xor r11, r11
xor r12, r12
xor r13, r13
xor r14, r14
xor r15, r15
/* It's now safe to go to APC */
mov rax, APC_LEVEL
mov cr8, rax
/* We have the KSTART_FRAME on the stack, P1Home and P2Home are preloaded
* with the parameters for the system routine. The address of the system
* routine is stored in P4Home. */
mov rcx, [rsp + SfP1Home] /* StartRoutine */
mov rdx, [rsp + SfP2Home] /* StartContext */
mov r8, [rsp + SfP3Home] /* ? */
call qword ptr [rsp + SfP4Home] /* SystemRoutine */
/* The thread returned. If it was a user-thread, we have a return address
and all is well, otherwise this is very bad. */
mov rcx, [rsp + SfReturn]
or rcx, rcx
jnz .leave
/* A system thread returned...this is very bad! */
int 3
.leave:
/* It was a user thread, set our trapframe for the System Call Exit Dispatcher */
lea rcx, [rsp + 6 * 8 + KEXCEPTION_FRAME_LENGTH]
/* Return to the trap exit code */
add rsp, 5 * 8
ret
.ENDP
/*!
* \name KiSwapContextInternal
*
* \brief
* The KiSwapContextInternal routine switches context to another thread.
*
* \param cl
* The IRQL at wich the old thread is suspended
*
* \param rdx
* Pointer to the KTHREAD to which the caller wishes to switch from.
*
* \param r8
* Pointer to the KTHREAD to which the caller wishes to switch to.
*
* \return
* The WaitStatus of the Target Thread.
*
* \remarks
* ...
*
*--*/
.PROC KiSwapContextInternal
push rbp
.pushreg rbp
sub rsp, 6 * 8
.allocstack (6 * 8)
.endprolog
/* Save WaitIrql as KSWITCH_FRAME::ApcBypass */
mov [rsp + SwApcBypass], cl
/* Save kernel stack of old thread */
mov [rdx + KTHREAD_KernelStack], rsp
/* Load stack of new thread */
mov rsp, [r8 + KTHREAD_KernelStack]
/* Reload APC bypass */
mov cl, [rsp + SwApcBypass]
call KiSwapContextResume
/* Cleanup and return */
add rsp, 6 * 8
pop rbp
ret
.ENDP
/*!
* KiSwapContext
*
* \brief
* The KiSwapContext routine switches context to another thread.
*
* BOOLEAN
* KiSwapContext(KIRQL WaitIrql, PKTHREAD OldThread);
*
* \param WaitIrql <cl>
* The IRQL at wich the old thread is suspended
*
* \param OldThread <rdx>
* Pointer to the KTHREAD of the previous thread.
*
* \return
* The WaitStatus of the Target Thread.
*
* \remarks
* This is a wrapper around KiSwapContextInternal which will save all the
* non-volatile registers so that the Internal function can use all of
* them. It will also save the old current thread and set the new one.
*
* The calling thread does not return after KiSwapContextInternal until
* another thread switches to IT.
*
*--*/
PUBLIC KiSwapContext
.PROC KiSwapContext
/* Generate a KEXCEPTION_FRAME on the stack */
GENERATE_EXCEPTION_FRAME
/* Do the swap with the registers correctly setup */
mov r8, gs:[PcCurrentThread] /* Pointer to the new thread */
call KiSwapContextInternal
/* Restore the registers from the KEXCEPTION_FRAME */
RESTORE_EXCEPTION_STATE
/* Return */
ret
.ENDP
END