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// TITLE("Thread Startup")//++//// Copyright (c) 1990 Microsoft Corporation// Copyright (c) 1992, 1993 Digital Equipment Corporation//// Module Name://// threadbg.s//// Abstract://// This module implements the MIPS machine dependent code necessary to// startup a thread in kernel mode.//// Author://// David N. Cutler (davec) 28-Mar-1990// Joe Notarangelo 21-Apr-1992//// Environment://// Kernel mode only, IRQL APC_LEVEL.//// Revision History:////--
#include "ksalpha.h"
//++//// RoutineDescription://// The following code is never executed. Its purpose is to allow the// kernel debugger to walk call frames backwards through thread startup// and to support get/set user context.////--
NESTED_ENTRY(KiThreadDispatch, ExceptionFrameLength, zero)
lda sp, -ExceptionFrameLength(sp) // allocate exception frame stq ra, ExIntRa(sp) // save return address stq s0, ExIntS0(sp) // save integer regs 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 regs 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
//++//// Routine Description://// This routine is called at thread startup. Its function is to call the// initial thread procedure. If control returns from the initial thread// procedure and a user mode context was established when the thread// was initialized, then the user mode context is restored and control// is transfered to user mode. Otherwise a bug check will occur.////// Arguments://// sp - Supplies a pointer to the exception frame which contains the// startup parameters.//// Within Exception frame://// s0 - Supplies a boolean value that specified whether a user mode// thread context was established when the thread was initialized.//// s1 - Supplies the starting context parameter for the initial thread// procedure.//// s2 - Supplies the starting address of the initial thread routine.//// s3 - Supplies the starting address of the initial system routine.//// Return Value://// None.////--
ALTERNATE_ENTRY(KiThreadStartup)
//// Capture the arguments for startup from the exception frame.// After the arguments are captured, deallocate the exception frame.//
ldq s0, ExIntS0(sp) // capture user context boolean ldq s1, ExIntS1(sp) // set startup context parameter ldq s2, ExIntS2(sp) // set address of thread routine ldq s3, ExIntS3(sp) // capture startup routine address ldq s4, ExIntS4(sp) // restore s4 ldq s5, ExIntS5(sp) // restore s5 ldq fp, ExIntFp(sp) // restore trap frame pointer lda sp, ExceptionFrameLength(sp) // deallocate exception frame
//// Lower Irql to APC level.//
ldil a0, APC_LEVEL // set IRQL to APC level
SWAP_IRQL // lower IRQL
//// Jump to the startup routine with the address of the thread routine and// the startup context parameter.//
bis s2, zero, a0 // set address of thread routine bis s1, zero, a1 // set startup context parameter jsr ra, (s3) // call system startup routine
//// If we return and no user context was supplied then we have trouble.//
beq s0, 20f // if eq, no user context
//// Finish in common exception exit code which will restore the nonvolatile// registers and exit to user mode.//
br zero, KiExceptionExit // finish in exception exit code
//// An attempt was made to enter user mode for a thread that has no user mode// context. Generate a bug check.//
20: ldil a0, NO_USER_MODE_CONTEXT // set bug check code bsr ra, KeBugCheck // call bug check routine
.end KiThreadDispatch
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