excmgr.c

T-kernel 的extension源代码

system_down:
	BMS_DEBUG_PRINT(("\n***** OS SYSTEM DOWN *****\n"));
	BMS_DEBUG_PRINT(("INT:%03x PC:%08x SR:%08x TEA:%08x tid:%d\n",
		exccode, isp->spc, isp->ssr, excmsg.i.excaddr,
		excmsg.i.taskid));
	tm_monitor();	/* To BMS */
}

/*
 * System exception handler entry
 */
LOCAL void SysExcHdr( UW exccode, UW excinfo )
{
	ExcStack	*isp;

	Asm("stc r6_bank, %0": "=r"(isp));

	_SysExcHdr(exccode, excinfo, isp);
}

/*
 * Page fault handler
 *	EXC_TLBINV_R	0x040	TLB invalid (read)
 *	EXC_TLBINV_W	0x060	TLB invalid (write)
 *	EXC_FIRSTWRITE	0x080	First writing to page
 *	EXC_TLBPRO_W	0x0c0	TLB protection (write)
 *
 *	exccode	Exception code		(EXPEVT)
 *	excaddr	Exception address	(TEA)
 *	tlbway	TLB way			(MMUCR)	(*) No meaning in SH4.
 */
EXPORT W PageFaultHdr( UW exccode, VP excaddr, UW tlbway )
{
//IMPORT	W	DebugMonitorFlag;	/* debug.c */
	struct {
		UW		sp;
		UW		r4_bank1;
		UW		r0_bank1;
		ExcStack	i;
	} *isp;
	PTH	pth;
	PTE	pte;
	ER	er;

	DO_DEBUG( pte.w = TSD_PFH_VAL_M1; )

	InitPTH(&pth, excaddr, 0);
	er = NextPTE(&pth);
	if ( er < E_OK ) {
		goto exception;		/* Invalid access */
	}
	pte.w = GetPTE(&pth);
	if ( pte.w == PTE_NONE ) {
		goto exception;	/* Invalid access */
	}

	if ( exccode == EXC_TLBPRO_W ) {
		/* If copy-on-write is not available: access violation */
		if ( !((pte.c.cow != 0U) && (pte.c.w == 0U)) ) {
			goto exception;	/* Access violation */
		}
	}

	/* Set access bit */
	(void)ChgPTE(&pth, PT_Accessed, ~PT_Accessed, FALSE);

	if ( ((exccode == EXC_TLBINV_R) || (exccode == EXC_TLBINV_W))
	  && (pte.c.p != 0) ) {
		/* TLB loading only */
		LoadTLB(&pth, tlbway);

	} else if ( ((exccode == EXC_TLBINV_R) || (exccode == EXC_TLBINV_W))
	  && (pte.c.va != 0) && (SegLock.cnt < 0) ) {
		/* Since the page is valid, make page frame settings only.
		 * However, if LockSEG() cannot be handled here,
		 * pass it to an exception handling task.
		 */
		PFE *pfe = PFAtoPFE(pte.c.pfa);
		MovePageFrame(pfe, PFS_use);
		(void)ChgPTE(&pth, PT_Present, ~PT_Present, FALSE);
		LoadTLB(&pth, tlbway);

	} else if ( exccode == EXC_FIRSTWRITE ) {
		/* First writing: set dirty bit */
		(void)ChgPTE(&pth, PT_Update, ~PT_Update, FALSE);
		LoadTLB(&pth, tlbway);

	} else {
		ExcMsg		excmsg;

		Asm("stc r6_bank, %0": "=r"(isp));

		memset(&excmsg, 0, sizeof(excmsg));
		excmsg.i.exccode = exccode;
		excmsg.i.excaddr = (UW)excaddr;
		excmsg.pgfault = TRUE;

		/* Obtain intended task ID */
		excmsg.i.taskid = er = tk_get_tid();
		if ( er < E_OK ) {
			goto exception;
		}

		/* Handle it as exception if it occurred while a task independent section is executed or interrupt is disabled. */
		if ( ((isp->i.ssr & SR_I(TSD_HDR_MSK_15)) > 0U)
		  || TaskIndependent(&isp->i) ) {
			goto exception;
		}

		/* Suspend current task */
		er = tk_sus_tsk(excmsg.i.taskid);
		if ( er < E_OK ) {
			goto exception;
		}

		/* Notify to exception handling task */
		er = sendExcMsg(&excmsg);
		if ( er < E_OK ) {
			BMS_DEBUG_PRINT(("\nPageFaultHdr sendExcMsg er = %d\n", er));
			goto exception;
		}
	}

	EndPTH(&pth, FALSE);
	return 0;

exception:
	/* Exception not handled by segment management */
	EndPTH(&pth, FALSE);
	BMS_DEBUG_PRINT(("PageFaultHdr exccode=0x%08x excaddr=0x%08x"
				" pte=0x%08x er=%d\n",
				exccode, excaddr, pte.w, er));

	//if ( DebugMonitorFlag != 0 ) return 1;  /* To BMS */

	Asm("stc r6_bank, %0": "=r"(isp));
	_SysExcHdr(exccode, 0, &isp->i);

	return 0;
}

/*
 * Provisional page fault handler
 *	Used provisionally until T-Kernel/OS starts.
 *	Switched to a regular page fault handler after T-Kernel/OS startup.
 *
 *	EXC_TLBINV_R	0x040	TLB invalid (read)
 *	EXC_TLBINV_W	0x060	TLB invalid (write)
 *	EXC_FIRSTWRITE	0x080	First writing to page
 *
 *	exccode	Exception code		(EXPEVT)
 *	excaddr	Exception address	(TEA)
 *	tlbway	TLB way			(MMUCR)	(*) No meaning in SH4.
 */
EXPORT void TmpPageFaultHdr( UW exccode, VP excaddr, UW tlbway )
{
	PTH	pth;
	PTE	pte;
	ER	er;

	InitPTH(&pth, excaddr, 0);
	er = NextPTE(&pth);
	if ( er < E_OK ) {
		goto err_exit;
	}
	pte.w = GetPTE(&pth);
	if ( pte.w == PTE_NONE ) {
		goto err_exit;
	}

	if ( exccode == EXC_FIRSTWRITE ) {
		/* First writing: set dirty bit */
		(void)ChgPTE(&pth, PT_Update, ~PT_Update, FALSE);

	} else if ( pte.c.p == 0 ) {
		/* Page-in */
		er = PageIn(excaddr, 0);
		if ( er < E_OK ) {
			goto err_exit;
		}
	}

	LoadTLB(&pth, tlbway);
	EndPTH(&pth, FALSE);

	return;

err_exit:
	BMS_DEBUG_PRINT(("TmpPageFaultHdr exccode=0x%08x excaddr=0x%08x"
				" pte=0x%08x er=%d\n",
				exccode, excaddr, pte.w, er));
	tm_monitor();
}

/* ------------------------------------------------------------------------ */

/*
 * Entry address of the monitor's default handler
 */
IMPORT	FP	DefaultHandlerEntry;

/*
 * Register/deregister system exception handler
 *	regist = TRUE	Register
 *	regist = FALSE	Deregister
 */
EXPORT void RegistSysExcHdr( BOOL regist )
{
const	UW	DefaultHandler = TSD_RSH_DHL_0X1000;
	T_DINT	dint;

	dint.intatr = TA_HLNG;
	dint.inthdr = SysExcHdr;

	tk_def_int(DefaultHandler, ( regist != 0 )? &dint: NULL);
}

/*
 * Register page fault handler
 */
LOCAL ER RegistPageFaultHdr( void )
{
	T_DINT	dint;
	ER	er;

	/* Register other TLB-related exception handler */
	dint.intatr = TA_ASM;
	dint.inthdr = asmPageFaultHdr;

	er = tk_def_int(EXC_TLBINV_R, &dint);
	if ( er < E_OK ) {
		goto err_ret;
	}
	er = tk_def_int(EXC_TLBINV_W, &dint);
	if ( er < E_OK ) {
		goto err_ret;
	}
	er = tk_def_int(EXC_FIRSTWRITE, &dint);
	if ( er < E_OK ) {
		goto err_ret;
	}
	er = tk_def_int(EXC_TLBPRO_W, &dint);
	if ( er < E_OK ) {
		goto err_ret;
	}

	return E_OK;

err_ret:
	BMS_DEBUG_PRINT(("RegistPageFaultHdr er = %d\n", er));
	return er;
}

/*
 * Register provisional page fault handler
 */
EXPORT void RegistTmpPageFaultHdr( void )
{
	/* Save T-Monitor's default handler */
	DefaultHandlerEntry = SCArea->defaulthdr;

	/* Register TLB miss exception handler */
	SCArea->tlbmisshdr = asmTLBMissHdr;

	define_inthdr(EXC_TLBINV_R, asmTmpPageFaultHdr);
	define_inthdr(EXC_TLBINV_W, asmTmpPageFaultHdr);
	define_inthdr(EXC_FIRSTWRITE, asmTmpPageFaultHdr);
}

/*
 * Initialize system exception processing
 *	(immediately after T-Kernel/OS startup)
 */
EXPORT ER InitExcMgr( BOOL StartUp )
{
	T_CTSK	ctsk;
	T_DINT	dint;
	ER	er;

	if ( !StartUp ) {
		/* Termination processing: deregister at least the exception handler. */
		RegistSysExcHdr(FALSE);
		return E_OK;
	}

	/* Start system exception processing task */
	SetOBJNAME(ctsk.exinf, "SExc");
	ctsk.tskatr  = TA_HLNG|TA_RNG0;
	ctsk.task    = SysExcTsk;
	ctsk.itskpri = 1;
	ctsk.stksz   = TSD_IEM_STK_2048;
	er = tk_cre_tsk(&ctsk);
	if ( er < E_OK ) {
		goto err_ret;
	}
	er = tk_sta_tsk(SysExcTskID = er, 0);
	if ( er < E_OK ) {
		goto err_ret;
	}

	/* Register page fault handler */
	er = RegistPageFaultHdr();
	if ( er < E_OK ) {
		goto err_ret;
	}

	/* Register BMS_KILL_PROC handler */
	dint.intatr = TA_HLNG;
	dint.inthdr = SysExcHdr;
	er = tk_def_int(BMS_KILL_PROC << TSD_IEM_SFT_5, &dint);
	if ( er < E_OK ) {
		goto err_ret;
	}

	return E_OK;

err_ret:
	BMS_DEBUG_PRINT(("InitExcMgr: er = %d\n", er));
	return er;
}

/* ------------------------------------------------------------------------ */

/*
 * Set TLB exception handler for re-startup processing
 */
EXPORT void SetWarmBootTLBHdr( void )
{
IMPORT	void	warmBootTLBInvRHdr( void );
IMPORT	void	warmBootTLBMissHdr( void );

	SCArea->tlbmisshdr = warmBootTLBMissHdr;
	define_inthdr(EXC_TLBINV_R, warmBootTLBInvRHdr);

	*(_UW*)TTB = (UW)SATB;
}

/* ------------------------------------------------------------------------ */