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Add functions to save and restore processor context and control state
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This commit is contained in:
Aiken Harris
2026-06-07 20:33:02 +02:00
parent 904df63198
commit 47d4069d6f
3 changed files with 488 additions and 4 deletions
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220
xtoskrnl/ke/i686/proc.cc
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@@ -193,10 +193,193 @@ KE::Processor::RegisterProcessorBlock(ULONG CpuNumber,
}
/**
* Saves the current processor state.
* Restores the processor's architectural state from the provided context frame back into the hardware trap
* and exception frames.
*
* @param TrapFrame
* Supplies a pointer to the trap frame that will receive the volatile processor state and control registers.
*
* @param ExceptionFrame
* Supplies a pointer to the exception frame that will receive the non-volatile integer and FP registers.
*
* @param ContextFrame
* Supplies a pointer to the context frame containing the state to be restored.
*
* @param ContextFlags
* Supplies a bitmask indicating which specific register groups should be restored from the ContextFrame.
*
* @return This routine does not return any value.
*
* @since XT 1.0
*/
XTAPI
VOID
KE::Processor::RestoreProcessorContext(IN OUT PKTRAP_FRAME TrapFrame,
IN OUT PKEXCEPTION_FRAME ExceptionFrame,
IN PCONTEXT ContextFrame,
IN ULONG ContextFlags)
{
UNIMPLEMENTED;
}
/**
* Restores the processor's low-level hardware control state.
*
* @param CpuState
* Supplies a pointer to the processor state block containing the previously saved control data.
*
* @return This routine does not return any value.
*
* @since XT 1.0
*/
XTAPI
VOID
KE::Processor::RestoreProcessorControlState(IN PKPROCESSOR_STATE CpuState)
{
/* Restore CR registers */
AR::CpuFunctions::WriteControlRegister(0, CpuState->SpecialRegisters.Cr0);
AR::CpuFunctions::WriteControlRegister(2, CpuState->SpecialRegisters.Cr2);
AR::CpuFunctions::WriteControlRegister(3, CpuState->SpecialRegisters.Cr3);
AR::CpuFunctions::WriteControlRegister(4, CpuState->SpecialRegisters.Cr4);
/* Restore DR registers */
AR::CpuFunctions::WriteDebugRegister(0, CpuState->SpecialRegisters.KernelDr0);
AR::CpuFunctions::WriteDebugRegister(1, CpuState->SpecialRegisters.KernelDr1);
AR::CpuFunctions::WriteDebugRegister(2, CpuState->SpecialRegisters.KernelDr2);
AR::CpuFunctions::WriteDebugRegister(3, CpuState->SpecialRegisters.KernelDr3);
AR::CpuFunctions::WriteDebugRegister(6, CpuState->SpecialRegisters.KernelDr6);
AR::CpuFunctions::WriteDebugRegister(7, CpuState->SpecialRegisters.KernelDr7);
/* Restore GDT, IDT, LDT and TaskRegister */
AR::CpuFunctions::LoadGlobalDescriptorTable(&CpuState->SpecialRegisters.Gdtr.Limit);
AR::CpuFunctions::LoadInterruptDescriptorTable(&CpuState->SpecialRegisters.Idtr.Limit);
AR::CpuFunctions::LoadLocalDescriptorTable(CpuState->SpecialRegisters.Ldtr);
AR::CpuFunctions::LoadTaskRegister(CpuState->SpecialRegisters.Tr);
}
/**
* Restores the executing processor's state.
*
* @param TrapFrame
* Supplies a pointer to the hardware trap frame that will be populated with the restored volatile state.
*
* @param ExceptionFrame
* Supplies a pointer to the exception frame that will be populated with the restored non-volatile state.
*
* @return This routine does not return any value.
*
* @since XT 1.0
*/
XTAPI
VOID
KE::Processor::RestoreProcessorState(OUT PKTRAP_FRAME TrapFrame,
OUT PKEXCEPTION_FRAME ExceptionFrame)
{
PKPROCESSOR_CONTROL_BLOCK Prcb;
/* Retrieve current processor control block */
Prcb = GetCurrentProcessorControlBlock();
/* Restore processor context */
RestoreProcessorContext(TrapFrame, ExceptionFrame, &Prcb->ProcessorState.ContextFrame,
CONTEXT_FULL | CONTEXT_DEBUG_REGISTERS);
/* Restore processor control registers */
RestoreProcessorControlState(&Prcb->ProcessorState);
}
/**
* Constructs a standardized processor context from the hardware trap and exception frames.
*
* @param TrapFrame
* Supplies a pointer to the trap frame containing volatile processor state, control registers and debug
* registers saved at the time of the interrupt or exception.
*
* @param ExceptionFrame
* Supplies a pointer to the exception frame containing non-volatile integer and floating-point registers.
*
* @param ContextFrame
* Supplies a pointer to the context frame that will receive the processor state.
*
* @return This routine does not return any value.
*
* @since XT 1.0
*/
XTAPI
VOID
KE::Processor::SaveProcessorContext(IN PKTRAP_FRAME TrapFrame,
IN PKEXCEPTION_FRAME ExceptionFrame,
IN OUT PCONTEXT ContextFrame)
{
/* Elevate RunLevel to APC_LEVEL to prevent thread preemption */
KE::RaiseRunLevel RunLevel(APC_LEVEL);
/* Check if control registers are requested */
if(ContextFrame->ContextFlags & CONTEXT_CONTROL)
{
/* Copy instruction pointer, stack pointer, and CPU status flags */
ContextFrame->Flags = TrapFrame->Flags;
ContextFrame->Ebp = TrapFrame->Ebp;
ContextFrame->Eip = TrapFrame->Eip;
ContextFrame->Esp = TrapFrame->Esp;
ContextFrame->SegCs = TrapFrame->SegCs;
ContextFrame->SegSs = TrapFrame->SegSs;
}
/* Check if general-purpose integer registers are requested */
if(ContextFrame->ContextFlags & CONTEXT_INTEGER)
{
/* Copy integer registers directly from the trap frame */
ContextFrame->Eax = TrapFrame->Eax;
ContextFrame->Ebx = TrapFrame->Ebx;
ContextFrame->Ecx = TrapFrame->Ecx;
ContextFrame->Edx = TrapFrame->Edx;
ContextFrame->Edi = TrapFrame->Edi;
ContextFrame->Esi = TrapFrame->Esi;
}
/* Check if segment registers are requested */
if(ContextFrame->ContextFlags & CONTEXT_SEGMENTS)
{
/* Populate segment selectors with standard Ring 3 values */
TrapFrame->SegDs = KGDT_R3_DATA | RPL_MASK;
TrapFrame->SegEs = KGDT_R3_DATA | RPL_MASK;
TrapFrame->SegFs = KGDT_R0_PB;
TrapFrame->SegGs = 0;
}
/* Check if floating-point registers are requested and if running in user mode */
if((ContextFrame->ContextFlags & CONTEXT_FLOATING_POINT) && ((TrapFrame->SegCs & MODE_MASK) == UserMode))
{
/* No user-mode support */
UNIMPLEMENTED;
}
/* Check if debug registers are requested */
if(ContextFrame->ContextFlags & CONTEXT_DEBUG_REGISTERS)
{
/* Copy debug registers */
ContextFrame->Dr0 = TrapFrame->Dr0;
ContextFrame->Dr1 = TrapFrame->Dr1;
ContextFrame->Dr2 = TrapFrame->Dr2;
ContextFrame->Dr3 = TrapFrame->Dr3;
ContextFrame->Dr6 = TrapFrame->Dr6;
ContextFrame->Dr7 = TrapFrame->Dr7;
}
/* Check if extended registers are requested and if running in user mode */
if((ContextFrame->ContextFlags & CONTEXT_EXTENDED_REGISTERS) && ((TrapFrame->SegCs & MODE_MASK) == UserMode))
{
/* No user-mode support */
UNIMPLEMENTED;
}
}
/**
* Saves the current processor's low-level hardware control state.
*
* @param State
* Supplies a pointer to the processor state structure.
* Supplies a pointer to the processor state block that will receive processor's control data.
*
* @return This routine does not return any value.
*
@@ -226,3 +409,36 @@ KE::Processor::SaveProcessorControlState(OUT PKPROCESSOR_STATE CpuState)
AR::CpuFunctions::StoreLocalDescriptorTable(&CpuState->SpecialRegisters.Ldtr);
AR::CpuFunctions::StoreTaskRegister(&CpuState->SpecialRegisters.Tr);
}
/**
* Captures the executing processor's state.
*
* @param TrapFrame
* Supplies a pointer to the hardware trap frame containing the processor's volatile state.
*
* @param ExceptionFrame
* Supplies a pointer to the exception frame containing the processor's non-volatile state.
*
* @return This routine does not return any value.
*
* @since XT 1.0
*/
XTAPI
VOID
KE::Processor::SaveProcessorState(IN PKTRAP_FRAME TrapFrame,
IN PKEXCEPTION_FRAME ExceptionFrame)
{
PKPROCESSOR_CONTROL_BLOCK Prcb;
/* Retrieve current processor control block */
Prcb = GetCurrentProcessorControlBlock();
/* Set context flags to save whole full context and debug registers */
Prcb->ProcessorState.ContextFrame.ContextFlags = CONTEXT_FULL | CONTEXT_DEBUG_REGISTERS;
/* Save processor context */
SaveProcessorContext(TrapFrame, ExceptionFrame, &Prcb->ProcessorState.ContextFrame);
/* Save processor control registers */
SaveProcessorControlState(&Prcb->ProcessorState);
}