reactos/ntoskrnl/ke/i386/ctxswitch.S

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/*
* COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS kernel
* FILE: ntoskrnl/ke/i386/ctxswitch.S
* PURPOSE: Thread Context Switching
*
* PROGRAMMERS: Alex Ionescu (alex@relsoft.net)
* Gregor Anich (FPU Code)
*/
/* INCLUDES ******************************************************************/
#include <asm.inc>
#include <ks386.inc>
EXTERN @KiSwapContextEntry@8:PROC
EXTERN @KiSwapContextExit@8:PROC
EXTERN @KiRetireDpcList@4:PROC
EXTERN @KiEnterV86Mode@4:PROC
EXTERN @KiExitV86Mode@4:PROC
EXTERN _KeI386FxsrPresent:DWORD
/* FUNCTIONS ****************************************************************/
.code
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/*++
* KiSwapContextInternal
*
* \brief
* The KiSwapContextInternal routine switches context to another thread.
*
* BOOLEAN USERCALL KiSwapContextInternal(ULONG_PTR OldThreadAndApcFlag@<edx>);
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*
* \param OldThreadAndApcFlag@<edx>
* Pointer to the current thread with the lowest bit set to the current IRQL.
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*
* \returns
* APC state.
*
* \remarks
* Absolutely all registers except ESP can be trampled here for maximum code flexibility.
*
*--*/
PUBLIC @KiSwapContextInternal@0
@KiSwapContextInternal@0:
/* Build switch frame */
sub esp, 2 * 4
mov ecx, esp
jmp @KiSwapContextEntry@8
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/**
* KiSwapContext
*
* \brief
* The KiSwapContext routine switches context to another thread.
*
* BOOLEAN FASTCALL
* KiSwapContext(KIRQL WaitIrql@<cl>, PKTHREAD CurrentThread@<edx>);
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*
* \param WaitIrql@<cl>
* The IRQL at which the wait happens.
*
* \param CurrentThread@<edx>
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* Pointer to the KTHREAD of the current thread.
*
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* \returns
* 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
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* another thread switches to IT.
*
*--*/
PUBLIC @KiSwapContext@8
@KiSwapContext@8:
/* Save 4 registers */
sub esp, 4 * 4
/* Save all the non-volatile ones */
mov [esp+12], ebx
mov [esp+8], esi
mov [esp+4], edi
mov [esp+0], ebp
/* Combine current thread and the wait IRQL in edx */
or dl, cl
/* Do the swap with the registers correctly setup */
call @KiSwapContextInternal@0
/* Restore the registers */
mov ebp, [esp+0]
mov edi, [esp+4]
mov esi, [esp+8]
mov ebx, [esp+12]
/* Clean stack */
add esp, 4 * 4
ret
PUBLIC @KiSwitchThreads@8
@KiSwitchThreads@8:
/* Load the new kernel stack and switch OS to new thread */
mov esp, edx
#if DBG
/* Restore the frame pointer early to get sensible backtraces */
mov ebp, [esp+12]
#endif
call @KiSwapContextExit@8
/* Now we're on the new thread. Return to the caller to restore registers */
add esp, 2 * 4
ret
PUBLIC @KiRetireDpcListInDpcStack@8
@KiRetireDpcListInDpcStack@8:
/* Switch stacks and retire DPCs */
mov eax, esp
mov esp, edx
push eax
call @KiRetireDpcList@4
/* Return on original stack */
pop esp
ret
PUBLIC _Ki386EnableCurrentLargePage@8
_Ki386EnableCurrentLargePage@8:
/* Save StartAddress in eax */
mov eax, [esp + 4]
/* Save new CR3 value in ecx */
mov ecx, [esp + 8]
/* Save flags value */
pushfd
/* Disable interrupts */
cli
/* Compute linear address */
sub eax, offset _Ki386EnableCurrentLargePage@8
add eax, offset _Ki386LargePageIdentityLabel
/* Save old CR3 in edx and replace with a new one */
mov edx, cr3
mov cr3, ecx
/* Jump to the next instruction but in linear mapping */
jmp eax
_Ki386LargePageIdentityLabel:
/* Disable paging */
mov eax, cr0
and eax, NOT CR0_PG
mov cr0, eax
/* Jump to the next instruction to clear the prefetch queue */
jmp $+2
/* Enable Page Size Extension in CR4 */
mov ecx, cr4
or ecx, CR4_PSE
mov cr4, ecx
/* Done, now re-enable paging */
or eax, CR0_PG
mov cr0, eax
/* Jump to virtual address */
mov eax, offset VirtualSpace
jmp eax
VirtualSpace:
/* Restore CR3 contents */
mov cr3, edx
/* Restore flags */
popfd
ret 8
/* FIXFIX: Move to C code ****/
PUBLIC _Ki386SetupAndExitToV86Mode@4
_Ki386SetupAndExitToV86Mode@4:
/* Enter V8086 mode */
pushad
sub esp, (12 + KTRAP_FRAME_LENGTH + NPX_FRAME_LENGTH + 16)
mov ecx, esp
call @KiEnterV86Mode@4
jmp $
PUBLIC @Ki386BiosCallReturnAddress@4
@Ki386BiosCallReturnAddress@4:
/* Exit V8086 mode */
call @KiExitV86Mode@4
mov esp, eax
add esp, (12 + KTRAP_FRAME_LENGTH + NPX_FRAME_LENGTH + 16)
popad
ret 4
PUBLIC _FrRestore
PUBLIC @Ke386LoadFpuState@4
@Ke386LoadFpuState@4:
/* Check if we have FXSR and choose which operand to use */
test byte ptr [_KeI386FxsrPresent], 1
jz _FrRestore
/* Restore all the FPU, MMX, XMM and MXCSR registers */
fxrstor [ecx]
ret
/*
* Just restore the basic FPU registers.
* This may raise an exception depending
* on the status word, which KiNpxHandler will
* need to check for and handle during delayed load
* to avoid raising an unhandled exception
* and crashing the system.
*/
_FrRestore:
frstor [ecx]
ret
END