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// TITLE("Kernel Trap Handler")//++// Copyright (c) 1990 Microsoft Corporation// Copyright (c) 1992 Digital Equipment Corporation//// Module Name://// trap.s////// Abstract://// Implements trap routines for ALPHA, these are the// entry points that the palcode calls for exception// processing.////// Author://// David N. Cutler (davec) 4-Apr-1990// Joe Notarangelo 06-Feb-1992////// Environment://// Kernel mode only.////// Revision History://// Nigel Haslock 05-May-1995 preserve fpcr across system calls////--
#include "ksalpha.h"
//// Define exception handler frame//
.struct 0HdRa: .space 8 // return address .space 3*8 // round to cache blockHandlerFrameLength: // frame length SBTTL("General Exception Dispatch")//++//// Routine Description://// The following code is never executed. Its purpose is to allow the// kernel debugger to walk call frames backwards through an exception// to support unwinding through exceptions for system services, and to// support get/set user context.//// N.B. The volatile registers must be saved in this prologue because// the compiler will occasionally generate code that uses volatile// registers to save the contents of nonvolatile registers when// a function only calls another function with a known register// signature (such as _OtsDivide).////--
NESTED_ENTRY(KiGeneralExceptionDispatch, TrapFrameLength, zero)
.set noreorder stq sp, TrIntSp(sp) // save stack pointer stq ra, TrIntRa(sp) // save return address stq ra, TrFir(sp) // save return address stq fp, TrIntFp(sp) // save frame pointer stq gp, TrIntGp(sp) // save global pointer bis sp, sp, fp // set frame pointer .set reorder
stq v0, TrIntV0(sp) // save integer register v0 stq t0, TrIntT0(sp) // save integer registers t0 - t7 stq t1, TrIntT1(sp) // stq t2, TrIntT2(sp) // stq t3, TrIntT3(sp) // stq t4, TrIntT4(sp) // stq t5, TrIntT5(sp) // stq t6, TrIntT6(sp) // stq t7, TrIntT7(sp) // stq a4, TrIntA4(sp) // save integer registers a4 - a5 stq a5, TrIntA5(sp) // stq t8, TrIntT8(sp) // save integer registers t8 - t12 stq t9, TrIntT9(sp) // stq t10, TrIntT10(sp) // stq t11, TrIntT11(sp) // stq t12, TrIntT12(sp) //
.set noat stq AT, TrIntAt(sp) // save integer register AT .set at
PROLOGUE_END
//++//// Routine Description://// PALcode dispatches to this kernel entry point when a "general"// exception occurs. These general exceptions are any exception// other than an interrupt, system service call or memory management// fault. The types of exceptions that will dispatch through this// routine will be: breakpoints, unaligned accesses, machine check// errors, illegal instruction exceptions, and arithmetic exceptions.// The purpose of this routine is to save the volatile state and// enter the common exception dispatch code.//// Arguments://// fp - Supplies a pointer to the trap frame.// gp - Supplies a pointer to the system short data area.// sp - Supplies a pointer to the trap frame.// a0 = Supplies a pointer to the exception record.// a3 = Supplies the previous psr.//// Note: Control registers, ra, sp, fp, gp have already been saved// argument registers a0-a3 have been saved as well////--
ALTERNATE_ENTRY(KiGeneralException)
bsr ra, KiGenerateTrapFrame // store volatile state br ra, KiExceptionDispatch // handle the exception
.end KiGeneralExceptionDispatch SBTTL("Exception Dispatch")//++//// Routine Description://// This routine begins the common code for raising an exception.// The routine saves the non-volatile state and dispatches to the// next level exception dispatcher.//// Arguments://// fp - Supplies a pointer to the trap frame.// sp - Supplies a pointer to the trap frame.// a0 = Supplies a pointer to the exception record.// a3 = Supplies the previous psr.//// gp, ra - saved in trap frame// a0-a3 - saved in trap frame//// Return Value://// None.////--
NESTED_ENTRY(KiExceptionDispatch, ExceptionFrameLength, zero )
//// Build exception frame//
lda sp, -ExceptionFrameLength(sp) // allocate exception frame stq ra, ExIntRa(sp) // save ra stq s0, ExIntS0(sp) // save integer registers s0 - s5 stq s1, ExIntS1(sp) // stq s2, ExIntS2(sp) // stq s3, ExIntS3(sp) // stq s4, ExIntS4(sp) // stq s5, ExIntS5(sp) // stt f2, ExFltF2(sp) // save floating registers f2 - f9 stt f3, ExFltF3(sp) // stt f4, ExFltF4(sp) // stt f5, ExFltF5(sp) // stt f6, ExFltF6(sp) // stt f7, ExFltF7(sp) // stt f8, ExFltF8(sp) // stt f9, ExFltF9(sp) //
PROLOGUE_END
ldil a4, TRUE // first chance to true and a3, PSR_MODE_MASK, a3 // set previous mode bis fp, zero, a2 // set pointer to trap frame bis sp, zero, a1 // set pointer to exception frame bsr ra, KiDispatchException // dispatch exception SBTTL("Exception Exit")//++//// Routine Description://// This routine is called to exit from an exception.//// N.B. This transfer of control occurs from://// 1. fall-through from above// 2. exit from continue system service// 3. exit from raise exception system service// 4. exit into user mode from thread startup//// Arguments://// fp - Supplies a pointer to the trap frame.// sp - Supplies a pointer to the exception frame.//// Return Value://// Does not return.////--
ALTERNATE_ENTRY(KiExceptionExit)
ldq s0, ExIntS0(sp) // restore integer registers s0 - s5 ldq s1, ExIntS1(sp) // ldq s2, ExIntS2(sp) // ldq s3, ExIntS3(sp) // ldq s4, ExIntS4(sp) // ldq s5, ExIntS5(sp) // ldl a0, TrPsr(fp) // get previous psr bsr ra, KiRestoreNonVolatileFloatState // restore nv float state
ALTERNATE_ENTRY(KiAlternateExit)
//// on entry://// a0 = Supplies the previous psr.//// rfe will do the following for us://// set sfw interrupt requests as per a1// restore previous irql and mode from previous psr// restore registers, a0-a3, fp, sp, ra, gp// return to saved exception address in the trap frame//// here, we need to restore the trap frame and determine// if we must request an APC interrupt//
bis zero, zero, a1 // assume softwareinterrupt requested blbc a0, 30f // if lbc, previous mode kernel
//// Check to determine if an apc interrupt should be generated.//
GET_CURRENT_THREAD // get current thread address
ldq_u t1, ThApcState+AsUserApcPending(v0) // get user APC pending extbl t1, (ThApcState+AsUserApcPending) % 8, t0 // ZeroByte(ThAlerted(v0)) // clear kernel mode alerted cmovne t0, APC_INTERRUPT, a1 // if pending set APC interrupt30: bsr ra, KiRestoreTrapFrame // restore volatile state
//// a0 = previous psr// a1 = sfw interrupt requests//
RETURN_FROM_TRAP_OR_INTERRUPT // return from exception
.end KiExceptionDispatch SBTTL("Memory Management Exception Dispatch")//++//// Routine Description://// The following code is never executed. Its purpose is to allow the// kernel debugger to walk call frames backwards through an exception// to support unwinding through exceptions for system services, and to// support get/set user context.//// N.B. The volatile registers must be saved in this prologue because// the compiler will occasionally generate code that uses volatile// registers to save the contents of nonvolatile registers when// a function only calls another function with a known register// signature (such as _OtsMove).////--
NESTED_ENTRY(KiMemoryManagementDispatch, TrapFrameLength, zero)
.set noreorder stq sp, TrIntSp(sp) // save stack pointer stq ra, TrIntRa(sp) // save return address stq ra, TrFir(sp) // save return address stq fp, TrIntFp(sp) // save frame pointer stq gp, TrIntGp(sp) // save global pointer bis sp, sp, fp // set frame pointer .set reorder
stq v0, TrIntV0(sp) // save integer register v0 stq t0, TrIntT0(sp) // save integer registers t0 - t7 stq t1, TrIntT1(sp) // stq t2, TrIntT2(sp) // stq t3, TrIntT3(sp) // stq t4, TrIntT4(sp) // stq t5, TrIntT5(sp) // stq t6, TrIntT6(sp) // stq t7, TrIntT7(sp) // stq a4, TrIntA4(sp) // save integer registers a4 - a5 stq a5, TrIntA5(sp) // stq t8, TrIntT8(sp) // save integer registers t8 - t12 stq t9, TrIntT9(sp) // stq t10, TrIntT10(sp) // stq t11, TrIntT11(sp) // stq t12, TrIntT12(sp) //
.set noat stq AT, TrIntAt(sp) // save integer register AT .set at
PROLOGUE_END
//++//// Routine Description://// This routine is called from the PALcode when a translation not valid// fault or an access violation is encountered. This routine will// call MmAccessFault to attempt to resolve the fault. If the fault// cannot be resolved then the routine will dispatch to the exception// dispatcher so the exception can be raised.//// Arguments://// fp - Supplies a pointer to the trap frame.// gp - Supplies a pointer to the system short data area.// sp - Supplies a pointer to the trap frame.// a0 = Supplies the load/store indicator, 1 = store, 0 = load.// a1 = Supplies the bad virtual address.// a2 = Supplies the previous mode.// a3 = Supplies the previous psr.//// gp, ra - saved in trap frame// a0-a3 - saved in trap frame//// Return Value://// None.////--
ALTERNATE_ENTRY(KiMemoryManagementException)
bsr ra, KiGenerateTrapFrame // store volatile state
//// Save parameters in exception record and save previous psr.//
STP a0, TrExceptionRecord + ErExceptionInformation(fp) // set load/store
#if defined(_AXP64_)
stq a1, TrExceptionRecord + ErExceptionInformation + 8(fp) // set bad va
#else
stl a1, TrExceptionRecord + ErExceptionInformation + 4(fp) // set bad va
#endif
stl a3, TrExceptionRecord + ErExceptionCode(fp) // save previous psr
//// Call memory management to handle the access fault.//
bis fp, zero, a3 // set address of trap frame bsr ra, MmAccessFault // resolve memory management fault ldl a3, TrExceptionRecord + ErExceptionCode(fp) // get previous psr
//// Check if working set watch is enabled.//
ldl t0, PsWatchEnabled // get working set watch enable flag bis v0, zero, a0 // save status of fault resolution blt v0, 40f // if ltz, resolution not successful beq t0, 35f // if eq. zero, watch not enabled LDP a1, TrExceptionRecord + ErExceptionAddress(fp) // set exception address
#if defined(_AXP64_)
ldq a2, TrExceptionRecord + ErExceptionInformation + 8(fp) // set bad address
#else
ldl a2, TrExceptionRecord + ErExceptionInformation + 4(fp) // set bad address
#endif
bsr ra, PsWatchWorkingSet // record working set information
//// Check if debugger has any breakpoints that should be inserted.//
35: ldl t0, KdpOweBreakpoint // get owned breakpoint flag zap t0, 0xfe, t1 // mask off high bytes beq t1, 37f // if eq, no break points owed bsr ra, KdSetOwedBreakpoints // set owed break points
//// Exit exception.//
37: ldl a0, TrPsr(fp) // get previous psr br zero, KiAlternateExit // exception handled
//// Check to determine if the fault occured in the interlocked pop// entry slist code. There is a case where a fault may occur in this// code when the right set of circumstances occurs. The fault can be// ignored by simply skipping the faulting instruction.//
40: ldq t0, TrFir(fp) // get faulting instruction address lda t1, ExpInterlockedPopEntrySListFault // get address of pop code cmpeq t0, t1, t2 // check if address matches bne t2, 70f // if ne, fault address match
//// Memory management failed to resolve fault.//// STATUS_IN_PAGE_ERROR | 0x10000000 is a special status that indicates a// page fault at Irql greater than APC_LEVEL.//// The following statuses can be raised://// STATUS_ACCESS_VIOLATION// STATUS_GUARD_PAGE_VIOLATION// STATUS_STACK_OVERFLOW//// All other status will be set to://// STATUS_IN_PAGE_ERROR//// dispatch exception via common code in KiDispatchException// Following must be done:// allocate exception frame via sp// complete data in ExceptionRecord// a0 points to ExceptionRecord// a1 points to ExceptionFrame// a2 points to TrapFrame// a3 = previous psr//// Exception record information has the following values// offset value// 0 read vs write indicator (set on entry)// 4 bad virtual address (set on entry)// 8 real status (only if status was not "recognized")////// Check for special status that indicates a page fault at// Irql above APC_LEVEL.//
ldil t1, STATUS_IN_PAGE_ERROR | 0x10000000 // get special status cmpeq v0, t1, t2 // check if status is special case bne t2, 60f // if ne, status is special case
//// Check for expected status values.//
lda a0, TrExceptionRecord(fp) // get exception record address bis zero, 2, t0 // set number of parameters ldil t1, STATUS_ACCESS_VIOLATION // get access violation code cmpeq v0, t1, t2 // check if access violation bne t2, 50f // if ne, access violation ldil t1, STATUS_GUARD_PAGE_VIOLATION // get guard page violation code cmpeq v0, t1, t2 // check if guard page violation bne t2, 50f // if ne, guard page violation ldil t1, STATUS_STACK_OVERFLOW // get stack overflow code cmpeq v0, t1, t2 // check if stack overflow bne t2, 50f // if ne, stack overflow
//// Status is not recognized, save real status, bump the number// of exception parameters, and set status to STATUS_IN_PAGE_ERROR//
#if defined(_AXP64_)
stq v0, ErExceptionInformation + 16(a0) // save real status code
#else
stl v0, ErExceptionInformation + 8(a0) // save real status code
#endif
bis zero, 3, t0 // set number of params ldil v0, STATUS_IN_PAGE_ERROR // set status to in page error
//// Fill in the remaining exception record parameters and attempt to// resolve the exception.//
50: ldl a3, ErExceptionCode(a0) // get previous psr stl v0, ErExceptionCode(a0) // save exception code stl zero, ErExceptionFlags(a0) // set exception flags STP zero, ErExceptionRecord(a0) // set associated record stl t0, ErNumberParameters(a0) // set number of parameters br ra, KiExceptionDispatch // dispatch exception
//// Generate a bugcheck - A page fault has occured at an IRQL that is greater// than APC_LEVEL.//
60: ldil a0, IRQL_NOT_LESS_OR_EQUAL // set bugcheck code
#if defined(_AXP64_)
ldq a1, TrExceptionRecord + ErExceptionInformation + 8(fp) // set bad va
#else
ldl a1, TrExceptionRecord + ErExceptionInformation + 4(fp) // set bad va
#endif
ldl a2, TrExceptionRecord + ErExceptionCode(fp) // set previous IRQL srl a2, PSR_IRQL, a2 // LDP a3, TrExceptionRecord + ErExceptionInformation(fp) // set load/store indicator ldq a4, TrFir(fp) // set exception pc br ra, KeBugCheckEx // handle bugcheck
//// The fault occured in the interlocked pop slist function and the faulting// instruction should be skipped.//
70: lda t0, ExpInterlockedPopEntrySListResume // get resumption address stq t0, TrFir(fp) // set continuation address ldl a0, TrPsr(fp) // get previous psr br zero, KiAlternateExit //
.end KiMemoryManagementDispatch SBTTL("Invalid Access Allowed")//++//// BOOLEAN// KeInvalidAccessAllowed (// IN PVOID TrapFrame// )//// Routine Description://// Mm will pass a pointer to a trap frame prior to issuing a bug check on// a pagefault. This routine lets Mm know if it is ok to bugcheck. The// specific case we must protect are the interlocked pop sequences which can// blindly access memory that may have been freed and/or reused prior to the// access. We don't want to bugcheck the system in these cases, so we check// the instruction pointer here.//// Arguments://// TrapFrame (a0) - Supplies a trap frame pointer. NULL means return False.//// Return Value://// True if the invalid access should be ignored.// False which will usually trigger a bugcheck.////--
LEAF_ENTRY(KeInvalidAccessAllowed)
bis zero, 0, v0 // assume access not allowed beq a0, 10f // if eq, no trap frame specified ldq t0, TrFir(a0) // get faulting instruction address lda t1, ExpInterlockedPopEntrySListFault // get address of pop code cmpeq t0, t1, v0 // check if fault at pop code address10: ret zero, (ra) // return
.end KeInvalidAccessAllowed SBTTL("Primary Interrupt Dispatch")//++//// Routine Description://// The following code is never executed. Its purpose is to allow the// kernel debugger to walk call frames backwards through an exception,// to support unwinding through exceptions for system services, and to// support get/set user context.//// N.B. The volatile registers must be saved in this prologue because// the compiler will occasionally generate code that uses volatile// registers to save the contents of nonvolatile registers when// a function only calls another function with a known register// signature (such as _OtsMove)////--
EXCEPTION_HANDLER(KiInterruptHandler)
NESTED_ENTRY(KiInterruptDistribution, TrapFrameLength, zero);
.set noreorder stq sp,TrIntSp(sp) // save stack pointer stq ra,TrIntRa(sp) // save return address stq ra,TrFir(sp) // save return address stq fp,TrIntFp(sp) // save frame pointer stq gp,TrIntGp(sp) // save general pointer bis sp, sp, fp // set frame pointer .set reorder
stq v0, TrIntV0(sp) // save integer register v0 stq t0, TrIntT0(sp) // save integer registers t0 - t7 stq t1, TrIntT1(sp) // stq t2, TrIntT2(sp) // stq t3, TrIntT3(sp) // stq t4, TrIntT4(sp) // stq t5, TrIntT5(sp) // stq t6, TrIntT6(sp) // stq t7, TrIntT7(sp) // stq a4, TrIntA4(sp) // save integer registers a4 - a5 stq a5, TrIntA5(sp) // stq t8, TrIntT8(sp) // save integer registers t8 - t12 stq t9, TrIntT9(sp) // stq t10, TrIntT10(sp) // stq t11, TrIntT11(sp) // stq t12, TrIntT12(sp) //
.set noat stq AT, TrIntAt(sp) // save integer register AT .set at
PROLOGUE_END
//++//// Routine Description://// The PALcode dispatches to this routine when an enabled interrupt// is asserted.//// When this routine is entered, interrupts are disabled.//// The function of this routine is to determine the highest priority// pending interrupt, raise the IRQL to the level of the highest interrupt,// and then dispatch the interrupt to the proper service routine.////// Arguments://// a0 - Supplies the interrupt vector number.// a1 - Supplies the address of the pcr.// a3 - Supplies the previous psr.// fp - Supplies a pointer to the trap frame.// gp - Supplies a pointer to the system short data area.//// Return Value://// None.////--
ALTERNATE_ENTRY(KiInterruptException)
bsr ra, KiSaveVolatileIntegerState // save integer registers
//// Count the number of interrupts.//
GET_PROCESSOR_CONTROL_BLOCK_BASE // get current prcb address
ldl t0, PbInterruptCount(v0) // get current count of interrupts addl t0, 1, t1 // increment count stl t1, PbInterruptCount(v0) // save new interrupt count
//// If interrupt vector > DISPATCH_LEVEL, indicate interrupt active in PRCB//
cmpule a0, DISPATCH_LEVEL, t4 // compare vector to DISPATCH_LEVEL LDP t2, PbInterruptTrapFrame(v0)// get old interrupt trap frame cmovne t4, zero, t2 // zero trap frame if <= DISPATCH_LEVEL STP t2, TrTrapFrame(fp) // save old interrupt trap in new bne t4, 10f // vector <= DISPATCH_LEVEL, no interrupt trap STP fp, PbInterruptTrapFrame(v0)// set new interrupt trap frame10: SPADDP a0, a1, a0 // convert index to offset + PCR base LDP a0, PcInterruptRoutine(a0) // get service routine address jsr ra, (a0) // call interrupt service routine
//// Restore state and exit interrupt.//
ldl a0, TrPsr(fp) // get previous psr
#ifndef NT_UP
DISABLE_INTERRUPTS // disable interrupts
#endif
GET_PROCESSOR_CONTROL_BLOCK_BASE // get current prcb address
LDP t0, TrTrapFrame(fp) // get old interrupt trap frame STP t0, PbInterruptTrapFrame(v0)// restore old interrupt trap frame
#ifndef NT_UP
ENABLE_INTERRUPTS // enable interrupts
#endif
bne t0, 50f // if ne, interrupt still active,
//// If a dispatch interrupt is pending, lower IRQL to DISPATCH_LEVEL, and// directly call the dispatch interrupt handler.//
ldl t2, PbSoftwareInterrupts(v0) // get pending SW interrupts beq t2, 50f // if eq, no pending SW interrupts stl zero, PbSoftwareInterrupts(v0) // clear pending SW interrupts and a0, PSR_IRQL_MASK, a1 // extract IRQL from PSR cmpult a1, DISPATCH_LEVEL << PSR_IRQL, t3 // check return IRQL beq t3, 70f // if not lt DISPATCH_LEVEL, can't bypass
//// Update count of bypassed dispatch interrupts.//
ldl t4, PbDpcBypassCount(v0) // get old bypass count addl t4, 1, t5 // increment stl t5, PbDpcBypassCount(v0) // store new bypass count ldil a0, DISPATCH_LEVEL // set new IRQL level
SWAP_IRQL // lower IRQL to DISPATCH_LEVEL
bsr ra, KiDispatchInterrupt // process dispatch interrupt45: ldl a0, TrPsr(fp) // restore previous psr
//// Check if an APC interrupt should be generated.//
50: bis zero, zero, a1 // clear sfw interrupt request blbc a0, 60f // if kernel no apc
GET_CURRENT_THREAD // get current thread address
ldq_u t1, ThApcState+AsUserApcPending(v0) // get user APC pending extbl t1, (ThApcState+AsUserApcPending) % 8, t0 // ZeroByte(ThAlerted(v0)) // clear kernel mode alerted cmovne t0, APC_INTERRUPT, a1 // if pending set APC interrupt60: bsr ra, KiRestoreVolatileIntegerState // restore volatile state
//// a0 = previous mode// a1 = sfw interrupt requests//
RETURN_FROM_TRAP_OR_INTERRUPT // return from trap/interrupt
//// Previous IRQL is >= DISPATCH_LEVEL, so a pending software interrupt cannot// be short-circuited. Request a software interrupt from the PAL.//
70: ldil a0, DISPATCH_LEVEL // set interrupt request level
REQUEST_SOFTWARE_INTERRUPT // request interrupt from PAL
br zero, 45b // rejoin common code
.end KiInterruptDistribution //++//// EXCEPTION_DISPOSITION// KiInterruptHandler (// IN PEXCEPTION_RECORD ExceptionRecord,// IN ULONG EstablisherFrame,// IN OUT PCONTEXT ContextRecord,// IN OUT PDISPATCHER_CONTEXT DispatcherContext//// Routine Description://// Control reaches here when an exception is not handled by an interrupt// service routine or an unwind is initiated in an interrupt service// routine that would result in an unwind through the interrupt dispatcher.// This is considered to be a fatal system error and bug check is called.//// Arguments://// ExceptionRecord (a0) - Supplies a pointer to an exception record.//// EstablisherFrame (a1) - Supplies the frame pointer of the establisher// of this exception handler.//// N.B. This is not actually the frame pointer of the establisher of// this handler. It is actually the stack pointer of the caller// of the system service. Therefore, the establisher frame pointer// is not used and the address of the trap frame is determined by// examining the saved fp register in the context record.//// ContextRecord (a2) - Supplies a pointer to a context record.//// DispatcherContext (a3) - Supplies a pointer to the dispatcher context// record.//// Return Value://// There is no return from this routine.////--
NESTED_ENTRY(KiInterruptHandler, HandlerFrameLength, zero)
lda sp, -HandlerFrameLength(sp) // allocate stack frame stq ra, HdRa(sp) // save return address
PROLOGUE_END
ldl t0, ErExceptionFlags(a0) // get exception flags ldil a0, INTERRUPT_UNWIND_ATTEMPTED // assume unwind in progress and t0, EXCEPTION_UNWIND, t1 // check if unwind in progress bne t1, 10f // if ne, unwind in progress ldil a0, INTERRUPT_EXCEPTION_NOT_HANDLED // set bug check code10: bsr ra, KeBugCheck // call bug check routine
.end KiInterruptHandler SBTTL("System Service Dispatch")//++//// Routine Description://// The following code is never executed. Its purpose is to allow the// kernel debugger to walk call frames backwards through an exception,// to support unwinding through exceptions for system services, and to// support get/set user context.////-- .struct 0ScCurrentThread: // current thread address .space 8 //ScServiceRoutine: // service routine address .space 8 //ScServiceDescriptor: // service descriptor address .space 8 //ScServiceNumber: // service number .space 4 // .space 4 // fillSyscallFrameLength: // frame length
EXCEPTION_HANDLER(KiSystemServiceHandler)
NESTED_ENTRY(KiSystemServiceDispatch, TrapFrameLength, zero);
.set noreorder stq sp, TrIntSp - TrapFrameLength(sp) // save stack pointer lda sp, -TrapFrameLength(sp) // allocate stack frame stq ra,TrIntRa(sp) // save return address stq ra,TrFir(sp) // save return address stq fp,TrIntFp(sp) // save frame pointer stq gp,TrIntGp(sp) // save general pointer bis sp, sp, fp // set frame pointer .set reorder
PROLOGUE_END
//++//// Routine Description://// Control reaches here when we have a system call call pal executed.// When this routine is entered, interrupts are disabled.//// The function of this routine is to call the specified system service.////// Arguments://// v0 - Supplies the system service code.// t0 - Previous processor mode// t1 - Current thread address// gp - Supplies a pointer to the system short data area.// fp - Supplies a pointer to the trap frame.//// Return Value://// None.////--
ALTERNATE_ENTRY(KiSystemServiceException)
START_REGION(KiSystemServiceDispatchStart)
mf_fpcr f0 // save floating control register stt f0, TrFpcr(fp) // lda sp, -SyscallFrameLength(sp) // allocate stack frame STP t1, ScCurrentThread(sp) // save current thread address ldq_u t4, ThPreviousMode(t1) // get old previous thread mode LDP t5, ThTrapFrame(t1) // get current trap frame address extbl t4, ThPreviousMode % 8, t3 // extract previous mode stl t3, TrPreviousMode(fp) // save old previous mode of thread StoreByte(t0, ThPreviousMode(t1)) // set new previous mode in thread STP t5, TrTrapFrame(fp) // save current trap frame address
//// If the specified system service number is not within range, then// attempt to convert the thread to a GUI thread and retry the service// dispatch.//// N.B. The argument registers a0-a3, the system service number in v0,// and the thread address in t1 must be preserved while attempting// to convert the thread to a GUI thread.//
ALTERNATE_ENTRY(KiSystemServiceRepeat)
STP fp, ThTrapFrame(t1) // save address of trap frame LDP t10, ThServiceTable(t1) // get service descriptor table address srl v0, SERVICE_TABLE_SHIFT, t2 // isolate service descriptor offset and t2, SERVICE_TABLE_MASK, t2 // ADDP t2, t10, t10 // compute service descriptor address ldl t3, SdLimit(t10) // get service number limit and v0, SERVICE_NUMBER_MASK, t7 // isolate service table offset cmpult t7, t3, t4 // check if valid service number beq t4, 80f // if eq, not valid service number LDP t4, SdBase(t10) // get service table address SPADDP t7, t4, t3 // compute address in service table LDP t5, 0(t3) // get address of service routine
#if DBG
LDP t6, SdCount(t10) // get service count table address beq t6, 5f // if eq, table not defined S4ADDP t7, t6, t6 // compute system service offset value ldl t11, 0(t6) // increment system service count addl t11, 1, t11 // stl t11, 0(t6) // store result
#endif
//// If the system service is a GUI service and the GDI user batch queue is// not empty, then call the appropriate service to flush the user batch.//
5: cmpeq t2, SERVICE_TABLE_TEST, t2 // check if GUI system service beq t2, 15f // if eq, not GUI system service LDP t3, ThTeb(t1) // get current thread TEB address ldl t4, TeGdiBatchCount(t3) // get number of batched GDI calls beq t4, 15f // if eq, no batched calls STP t5, ScServiceRoutine(sp) // save service routine address STP t10, ScServiceDescriptor(sp)// save service descriptor address stl t7, ScServiceNumber(sp) // save service table offset LDP t5, KeGdiFlushUserBatch // get address of flush routine stq a0, TrIntA0(fp) // save possible arguments stq a1, TrIntA1(fp) // stq a2, TrIntA2(fp) // stq a3, TrIntA3(fp) // stq a4, TrIntA4(fp) // stq a5, TrIntA5(fp) // jsr ra, (t5) // flush GDI user batch ldq a0, TrIntA0(fp) // restore possible arguments ldq a1, TrIntA1(fp) // ldq a2, TrIntA2(fp) // ldq a3, TrIntA3(fp) // ldq a4, TrIntA4(fp) // ldq a5, TrIntA5(fp) // LDP t5, ScServiceRoutine(sp) // restore service routine address LDP t10, ScServiceDescriptor(sp) // restore service descriptor address ldl t7, ScServiceNumber(sp) // restore service table offset
//// Check if system service has any in memory arguments.//
15: blbc t5, 30f // if clear, no in memory arguments LDP t10, SdNumber(t10) // get argument table address ADDP t7, t10, t11 // compute address in argument table
//// The following code captures arguments that were passed in memory on the// callers stack. This is necessary to ensure that the caller does not modify// the arguments after they have been probed and is also necessary in kernel// mode because a trap frame has been allocated on the stack.//// If the previous mode is user, then the user stack is probed for readability.//
LDP t10, TrIntSp(fp) // get previous stack pointer beq t0, 10f // if eq, previous mode was kernel LDIP t2, MM_USER_PROBE_ADDRESS // get user probe address cmpult t10, t2, t4 // check if stack in user region cmoveq t4, t2, t10 // if eq, set invalid user stack address10: ldq_u t4, 0(t11) // get number of memory arguments * 8 extbl t4, t11, t9 // addl t9, 0x1f, t3 // round up to hexaword (32 bytes) bic t3, 0x1f, t3 // ensure hexaword alignment SUBP sp, t3, sp // allocate space on kernel stack bis sp, zero, t2 // set destination copy address ADDP t2, t3, t4 // compute destination end address
START_REGION(KiSystemServiceStartAddress)
//// This code is set up to load the cache block in the first// instruction and then perform computations that do not require// the cache while waiting for the data. In addition, the stores// are setup so they will be in order.//
20: ldq t6, 24(t10) // get argument from previous stack ADDP t10, 32, t10 // next hexaword on previous stack ADDP t2, 32, t2 // next hexaword on kernel stack cmpeq t2, t4, t11 // at end address? stq t6, -8(t2) // store argument on kernel stack ldq t7, -16(t10) // argument from previous stack ldq t8, -24(t10) // argument from previous stack ldq t9, -32(t10) // argument from previous stack stq t7, -16(t2) // save argument on kernel stack stq t8, -24(t2) // save argument on kernel stack stq t9, -32(t2) // save argument on kernel stack beq t11, 20b // if eq, get next block
END_REGION(KiSystemServiceEndAddress)
bic t5, 3, t5 // clear lower bits of service addr
//// Call system service.//
30: jsr ra, (t5)
//// Restore old trap frame address from the current trap frame and update// the number of system calls.//
ALTERNATE_ENTRY(KiSystemServiceExit)
bis v0, zero, t1 // save return status
GET_PROCESSOR_CONTROL_BLOCK_BASE // get processor block address
LDP t2, -SyscallFrameLength + ScCurrentThread(fp) // get current thread address LDP t3, TrTrapFrame(fp) // get old trap frame address ldl t10, PbSystemCalls(v0) // increment number of calls addl t10, 1, t10 // stl t10, PbSystemCalls(v0) // store result STP t3, ThTrapFrame(t2) // restore old trap frame address bis t1, zero, v0 // restore return status ldt f0, TrFpcr(fp) // restore floating control register mt_fpcr f0 // ldl a0, TrPsr(fp) // get previous processor status ldl t5, TrPreviousMode(fp) // get old previous mode StoreByte(t5, ThPreviousMode(t2)) // store previous mode in thread
//// Check if an APC interrupt should be generated.//
bis zero, zero, a1 // clear siftware interrupt request blbc a0, 70f // if kernel mode skip apc check ldq_u t1, ThApcState+AsUserApcPending(t2) // get user APC pending extbl t1, (ThApcState+AsUserApcPending) % 8, t0 // ZeroByte(ThAlerted(t2)) // clear kernel mode alerted cmovne t0, APC_INTERRUPT, a1 // if pending set APC interrupt
//// a0 = previous psr// a1 = sfw interrupt requests//
70: RETURN_FROM_SYSTEM_CALL // return to caller
//// The specified system service number is not within range. Attempt to// convert the thread to a GUI thread if specified system service is a// GUI service.//// N.B. The argument register a0-a5 and the system service number in v0// must be preserved if an attempt is made to convert the thread to// a GUI thread.//
80: cmpeq t2, SERVICE_TABLE_TEST, t2 // check if GUI system service beq t2, 55f // if eq, not GUI system service stl v0, ScServiceNumber(sp) // save system service number stq a0, TrIntA0(fp) // save argument registers a0-a5 stq a1, TrIntA1(fp) // stq a2, TrIntA2(fp) // stq a3, TrIntA3(fp) // stq a4, TrIntA4(fp) // stq a5, TrIntA5(fp) // bsr ra, PsConvertToGuiThread // attempt to convert to GUI thread bis v0, zero, t0 // save completion status lda fp, SyscallFrameLength(sp) // restore trap frame address
GET_CURRENT_THREAD // restore current thread address
bis v0, zero, t1 // set current thread address ldl v0, ScServiceNumber(sp) // restore system service number ldq a0, TrIntA0(fp) // restore argument registers a0-a5 ldq a1, TrIntA1(fp) // ldq a2, TrIntA2(fp) // ldq a3, TrIntA3(fp) // ldq a4, TrIntA4(fp) // ldq a5, TrIntA5(fp) // beq t0, KiSystemServiceRepeat // if eq, successful conversion
//// The conversion to a Gui thread failed. The correct return value is encoded// in a byte table indexed by the service number that is at the end of the// service address table. The encoding is as follows://// 0 - return 0.// -1 - return -1.// 1 - return status code.//
lda t2, KeServiceDescriptorTableShadow // get descriptor base address ldl t3, SERVICE_TABLE_TEST + SdLimit(t2) // get service number limit LDP t4, SERVICE_TABLE_TEST + SdBase(t2) // get service table address SPADDP t3, t4, t2 // compute ending service table address and v0, SERVICE_NUMBER_MASK, t3 // isolate service number ADDP t2, t3, t3 // compute return value address ldq_u t2, 0(t3) // get packed status bytes extbl t2, t3, t2 // extract encoded status byte sll t2, 7 * 8, t2 // sign extend status byte value sra t2, 7 * 8, v0 // ble v0, KiSystemServiceExit // if le, return value set
//// Return invalid system service status for invalid service code.//
55: ldil v0, STATUS_INVALID_SYSTEM_SERVICE // set completion status br zero, KiSystemServiceExit //
END_REGION(KiSystemServiceDispatchEnd)
.end KiSystemServiceDispatch //++//// EXCEPTION_DISPOSITION// KiSystemServiceHandler (// IN PEXCEPTION_RECORD ExceptionRecord,// IN ULONG EstablisherFrame,// IN OUT PCONTEXT ContextRecord,// IN OUT PDISPATCHER_CONTEXT DispatcherContext// )//// Routine Description://// Control reaches here when a exception is raised in a system service// or the system service dispatcher, and for an unwind during a kernel// exception.//// If an unwind is being performed and the system service dispatcher is// the target of the unwind, then an exception occured while attempting// to copy the user's in-memory argument list. Control is transfered to// the system service exit by return a continue execution disposition// value.//// If an unwind is being performed and the previous mode is user, then// bug check is called to crash the system. It is not valid to unwind// out of a system service into user mode.//// If an unwind is being performed, the previous mode is kernel, the// system service dispatcher is not the target of the unwind, and the// thread does not own any mutexes, then the previous mode field from// the trap frame is restored to the thread object. Otherwise, bug// check is called to crash the system. It is invalid to unwind out of// a system service while owning a mutex.//// If an exception is being raised and the exception PC is within the// range of the system service dispatcher in-memory argument copy code,// then an unwind to the system service exit code is initiated.//// If an exception is being raised and the exception PC is not within// the range of the system service dispatcher, and the previous mode is// not user, then a continue searh disposition value is returned. Otherwise,// a system service has failed to handle an exception and bug check is// called. It is invalid for a system service not to handle all exceptions// that can be raised in the service.//// Arguments://// ExceptionRecord (a0) - Supplies a pointer to an exception record.//// EstablisherFrame (a1) - Supplies the frame pointer of the establisher// of this exception handler.//// N.B. This is not actually the frame pointer of the establisher of// this handler. It is actually the stack pointer of the caller// of the system service. Therefore, the establisher frame pointer// is not used and the address of the trap frame is determined by// examining the saved fp register in the context record.//// ContextRecord (a2) - Supplies a pointer to a context record.//// DispatcherContext (a3) - Supplies a pointer to the dispatcher context// record.//// Return Value://// If bug check is called, there is no return from this routine and the// system is crashed. If an exception occured while attempting to copy// the user in-memory argument list, then there is no return from this// routine, and unwind is called. Otherwise, ExceptionContinueSearch is// returned as the function value.////--
LEAF_ENTRY(KiSystemServiceHandler)
lda sp, -HandlerFrameLength(sp) // allocate stack frame stq ra, HdRa(sp) // save return address
PROLOGUE_END
ldl t0, ErExceptionFlags(a0) // get exception flags and t0, EXCEPTION_UNWIND, t1 // check if unwind in progress bne t1, 40f // if ne, unwind in progress
//// An exception is in progress.//// If the exception PC is within the in-memory argument copy code of the// system service dispatcher, then call unwind to transfer control to the// system service exit code. Otherwise, check if the previous mode is user// or kernel mode.////
LDP t0, ErExceptionAddress(a0) // get address of exception lda t1, KiSystemServiceStartAddress // address of system service cmpult t0, t1, t3 // check if before start range lda t2, KiSystemServiceEndAddress // end address bne t3, 10f // if ne, before start of range cmpult t0, t2, t3 // check if before end of range bne t3, 30f // if ne, before end of range
//// If the previous mode was kernel mode, then a continue search disposition// value is returned. Otherwise, the exception was raised in a system service// and was not handled by that service. Call bug check to crash the system.//
10: GET_CURRENT_THREAD // get current thread address
ldq_u t4, ThPreviousMode(v0) // get previous mode from thread extbl t4, ThPreviousMode % 8, t1 // bne t1, 20f // if ne, previous mode was user
//// Previous mode is kernel mode.//
ldil v0, ExceptionContinueSearch // set disposition code lda sp, HandlerFrameLength(sp) // deallocate stack frame jmp zero, (ra) // return
//// Previous mode is user mode. Call bug check to crash the system.//
20: bis a3, zero, a4 // set dispatcher context address bis a2, zero, a3 // set context record address bis a1, zero, a2 // set system service frame address bis a0, zero, a1 // set exception record address ldil a0, SYSTEM_SERVICE_EXCEPTION // set bug check code bsr ra, KeBugCheckEx // call bug check routine
//// The exception was raised in the system service dispatcher. Unwind to the// the system service exit code.//
30: ldl a3, ErExceptionCode(a0) // set return value bis zero, zero, a2 // set exception record address bis a1, zero, a0 // set target frame address lda a1, KiSystemServiceExit // set target PC address bsr ra, RtlUnwind // unwind to system service exit
//// An unwind is in progress.//// If a target unwind is being performed, then continue execution is returned// to transfer control to the system service exit code. Otherwise, restore the// previous mode if the previous mode is not user and there are no mutexes owned// by the current thread.//
40: and t0, EXCEPTION_TARGET_UNWIND, t1 // check if target unwnd in progres bne t1, 60f // if ne, target unwind in progress
//// An unwind is being performed through the system service dispatcher. If the// previous mode is not kernel or the current thread owns one or more mutexes,// then call bug check and crash the system. Otherwise, restore the previous// mode in the current thread object.//
GET_CURRENT_THREAD // get current thread address
ldl t1, CxIntFp(a2) // get address of trap frame ldq_u t4, ThPreviousMode(v0) // get previous mode from thread extbl t4, ThPreviousMode % 8, t3 // ldl t4,TrPreviousMode(t1) // get previous mode from trap frame bne t3, 50f // if ne, previous mode was user
//// Restore previous from trap frame to thread object and continue the unwind// operation.//
StoreByte(t4, ThPreviousMode(v0)) // restore previous mode from trap frame ldil v0, ExceptionContinueSearch // set disposition value lda sp, HandlerFrameLength(sp) // deallocate stack frame jmp zero, (ra) // return
//// An attempt is being made to unwind into user mode. Call bug check to crash// the system.//
50: ldil a0, SYSTEM_UNWIND_PREVIOUS_USER // set bug check code bsr ra, KeBugCheck // call bug check
//// A target unwind is being performed. Return a continue search disposition// value.//
60: ldil v0, ExceptionContinueSearch // set disposition value lda sp, HandlerFrameLength(sp) // deallocate stack frame jmp zero, (ra) // return
.end KiSystemServiceHandler //++//// Routine Description://// The following code is never executed. Its purpose is to allow the// kernel debugger to walk call frames backwards through an exception// to support unwinding through exceptions for system services, and to// support get/set user context.//--
NESTED_ENTRY(KiPanicDispatch, TrapFrameLength, zero)
.set noreorder stq sp, TrIntSp(sp) // save stack pointer stq ra, TrIntRa(sp) // save return address stq ra, TrFir(sp) // save return address stq fp, TrIntFp(sp) // save frame pointer stq gp, TrIntGp(sp) // save global pointer bis sp, sp, fp // set frame pointer .set reorder
PROLOGUE_END
//++//// Routine Description://// PALcode dispatches to this entry point when a panic situation// is detected while in PAL mode. The panic situation may be that// the kernel stack is about to overflow/underflow or there may be// a condition that was not expected to occur while in PAL mode// (eg. arithmetic exception while in PAL). This entry point is// here to help us debug the condition.//// Arguments://// fp - points to trap frame// sp - points to exception frame// a0 = Bug check code// a1 = Exception address// a2 = Bugcheck parameter// a3 = Bugcheck parameter//// gp, ra - saved in trap frame// a0-a3 - saved in trap frame//// Return Value://// None.////--
ALTERNATE_ENTRY(KiPanicException)
stq ra, TrIntRa(fp) // PAL is supposed to do this, but it doesn't!
//// Save state, volatile float and integer state via KiGenerateTrapFrame//
bsr ra, KiGenerateTrapFrame // save volatile state
//// Dispatch to KeBugCheckEx, does not return//
br ra, KeBugCheckEx // do the bugcheck
.end KiPanicDispatch //++//// VOID// KiBreakinBreakpoint(// VOID// );
//// Routine Description://// This routine issues a breakin breakpoint.//// Arguments://// None.//// Return Value://// None.////--
LEAF_ENTRY( KiBreakinBreakpoint )
BREAK_BREAKIN // execute breakin breakpoint
ret zero, (ra) // return to caller
.end KiBreakinBreakpoint
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