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kgdb_glue.c revision 1.2 
      1 /*	$NetBSD: kgdb_glue.c,v 1.2 2001/03/22 12:46:20 minoura Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1991, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This software was developed by the Computer Systems Engineering group
      8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
      9  * contributed to Berkeley.
     10  *
     11  * All advertising materials mentioning features or use of this software
     12  * must display the following acknowledgement:
     13  *	This product includes software developed by the University of
     14  *	California, Lawrence Berkeley Laboratories.
     15  *
     16  * Redistribution and use in source and binary forms, with or without
     17  * modification, are permitted provided that the following conditions
     18  * are met:
     19  * 1. Redistributions of source code must retain the above copyright
     20  *    notice, this list of conditions and the following disclaimer.
     21  * 2. Redistributions in binary form must reproduce the above copyright
     22  *    notice, this list of conditions and the following disclaimer in the
     23  *    documentation and/or other materials provided with the distribution.
     24  * 3. All advertising materials mentioning features or use of this software
     25  *    must display the following acknowledgement:
     26  *	This product includes software developed by the University of
     27  *	California, Berkeley and its contributors.
     28  * 4. Neither the name of the University nor the names of its contributors
     29  *    may be used to endorse or promote products derived from this software
     30  *    without specific prior written permission.
     31  *
     32  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     33  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     34  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     35  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     36  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     40  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     41  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     42  * SUCH DAMAGE.
     43  *
     44  *	@(#)kgdb_glue.c	8.2 (Berkeley) 1/12/94
     45  */
     46 
     47 /*
     48  * This file must be compiled with gcc -fno-defer-pop.
     49  */
     50 
     51 #ifdef KGDB
     52 
     53 #include <sys/param.h>
     54 
     55 #include <machine/frame.h>
     56 #include <machine/reg.h>
     57 
     58 #ifndef lint
     59 static char rcsid[] = "$NetBSD: kgdb_glue.c,v 1.2 2001/03/22 12:46:20 minoura Exp $";
     60 #endif
     61 
     62 #define KGDB_STACKSIZE 0x800
     63 #define KGDB_STACKWORDS (KGDB_STACKSIZE / sizeof(u_long))
     64 
     65 u_long kgdb_stack[KGDB_STACKWORDS];
     66 
     67 #define getsp(v) asm("movl %%sp, %0" : "=r" (v))
     68 #define setsp(v) asm("movl %0, %%sp" :: "r" (v))
     69 
     70 static inline void
     71 copywords(src, dst, nbytes)
     72 	register u_long *src, *dst;
     73 	register u_int nbytes;
     74 {
     75 	u_long *limit = src + (nbytes / sizeof(u_long));
     76 
     77 	do {
     78 		*dst++ = *src++;
     79 	} while (src < limit);
     80 	if (nbytes & 2)
     81 		*(u_short *)dst = *(u_short *)src;
     82 }
     83 
     84 kgdb_trap_glue(type, frame)
     85 	int type;
     86 	struct frame frame;
     87 {
     88 	u_long osp, nsp;
     89 	u_int fsize, s;
     90 	extern short exframesize[];
     91 
     92 	/*
     93 	 * After a kernel mode trap, the saved sp doesn't point to the right
     94 	 * place.  The correct value is the top of the frame (i.e. before the
     95 	 * KGDB trap).
     96 	 *
     97 	 * XXX this may have to change if we implement an interrupt stack.
     98 	 */
     99 	fsize = sizeof(frame) - sizeof(frame.F_u) + exframesize[frame.f_format];
    100 	frame.f_regs[SP] = (u_long)&frame + fsize;
    101 
    102 	/*
    103 	 * Copy the interrupt context and frame to the new stack.
    104 	 * We're throwing away trap()'s frame since we're going to do
    105 	 * our own rte.
    106 	 */
    107 	nsp = (u_long)&kgdb_stack[KGDB_STACKWORDS] -
    108 	      roundup(fsize, sizeof(u_long));
    109 
    110 	copywords((u_long *)&frame, (u_long *)nsp, fsize);
    111 
    112 	s = splhigh();
    113 
    114 	getsp(osp);
    115 	setsp(nsp);
    116 
    117 	if (kgdb_trap(type, (struct frame *)nsp) == 0) {
    118 		/*
    119 		 * Get back on kernel stack.  This thread of control
    120 		 * will return back up through trap().  If kgdb_trap()
    121 		 * returns 0, it didn't handle the trap at all so
    122 		 * the stack is still intact and everything will
    123 		 * unwind okay from here up.
    124 		 */
    125 		setsp(osp);
    126 		splx(s);
    127 		return 0;
    128 	}
    129 	/*
    130 	 * Copy back context, which has possibly changed.  Even the
    131 	 * sp might have changed.
    132 	 */
    133 	osp = ((struct frame *)nsp)->f_regs[SP] - fsize;
    134 	copywords((u_long *)nsp, (u_long *)osp, fsize);
    135 	setsp(osp);
    136 
    137 	/*
    138 	 * Restore the possible new context from frame, pop the
    139 	 * unneeded usp (we trapped from kernel mode) and pad word,
    140 	 * and return to the trapped thread.
    141 	 */
    142 	asm("moveml %sp@+,#0x7FFF; addql #8,sp; rte");
    143 }
    144 
    145 int kgdb_testval;
    146 
    147 kgdb_test(i)
    148 	int i;
    149 {
    150         ++kgdb_testval;
    151         return (i + 1);
    152 }
    153 #endif /* KGDB */
    154