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      1 /*	$NetBSD: kgdb_machdep.c,v 1.10 2020/06/20 15:45:22 skrll Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1996 Matthias Pfaller.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include <sys/cdefs.h>
     29 __KERNEL_RCSID(0, "$NetBSD: kgdb_machdep.c,v 1.10 2020/06/20 15:45:22 skrll Exp $");
     30 
     31 #include "opt_ddb.h"
     32 #include "opt_kgdb.h"
     33 
     34 #include <sys/param.h>
     35 
     36 #include <sys/kgdb.h>
     37 #include <sys/systm.h>
     38 
     39 #include <uvm/uvm_extern.h>
     40 
     41 #include <machine/frame.h>
     42 #include <machine/reg.h>
     43 #include <machine/trap.h>
     44 
     45 /*
     46  * Determine if the memory at va..(va+len) is valid.
     47  */
     48 int
     49 kgdb_acc(vaddr_t va, size_t len)
     50 {
     51 	vaddr_t last_va;
     52 
     53 	last_va = va + len;
     54 	va  &= ~PGOFSET;
     55 	last_va &= ~PGOFSET;
     56 
     57 	do {
     58 		if (db_validate_address(va))
     59 			return 0;
     60 		va  += PAGE_SIZE;
     61 	} while (va < last_va);
     62 
     63 	return 1;
     64 }
     65 
     66 /*
     67  * Translate a trap number into a unix compatible signal value.
     68  * (gdb only understands unix signal numbers).
     69  */
     70 int
     71 kgdb_signal(int type)
     72 {
     73 
     74 	switch (type) {
     75 	case T_BREAKPOINT:
     76 		return(SIGTRAP);
     77 	case -1:
     78 		return(SIGSEGV);
     79 	default:
     80 		return(SIGINT);
     81 	}
     82 }
     83 
     84 /*
     85  * Definitions exported from gdb.
     86  */
     87 
     88 /*
     89  * Translate the values stored in the kernel regs struct to the format
     90  * understood by gdb.
     91  */
     92 void
     93 kgdb_getregs(db_regs_t *regs, kgdb_reg_t *gdb_regs)
     94 {
     95 
     96 	gdb_regs[KGDB_REGNUM_R0 +  0] = regs->tf_r0;
     97 	gdb_regs[KGDB_REGNUM_R0 +  1] = regs->tf_r1;
     98 	gdb_regs[KGDB_REGNUM_R0 +  2] = regs->tf_r2;
     99 	gdb_regs[KGDB_REGNUM_R0 +  3] = regs->tf_r3;
    100 	gdb_regs[KGDB_REGNUM_R0 +  4] = regs->tf_r4;
    101 	gdb_regs[KGDB_REGNUM_R0 +  5] = regs->tf_r5;
    102 	gdb_regs[KGDB_REGNUM_R0 +  6] = regs->tf_r6;
    103 	gdb_regs[KGDB_REGNUM_R0 +  7] = regs->tf_r7;
    104 	gdb_regs[KGDB_REGNUM_R0 +  8] = regs->tf_r8;
    105 	gdb_regs[KGDB_REGNUM_R0 +  9] = regs->tf_r9;
    106 	gdb_regs[KGDB_REGNUM_R0 + 10] = regs->tf_r10;
    107 	gdb_regs[KGDB_REGNUM_R0 + 11] = regs->tf_r11;
    108 	gdb_regs[KGDB_REGNUM_R0 + 12] = regs->tf_r12;
    109 	gdb_regs[KGDB_REGNUM_R0 + 13] = regs->tf_svc_sp;
    110 	gdb_regs[KGDB_REGNUM_R0 + 14] = regs->tf_svc_lr;
    111 	gdb_regs[KGDB_REGNUM_R0 + 15] = regs->tf_pc;
    112 
    113 	gdb_regs[KGDB_REGNUM_SPSR] = regs->tf_spsr;
    114 }
    115 
    116 /*
    117  * Reverse the above.
    118  */
    119 void
    120 kgdb_setregs(db_regs_t *regs, kgdb_reg_t *gdb_regs)
    121 {
    122 	regs->tf_r0     = gdb_regs[KGDB_REGNUM_R0 +  0];
    123 	regs->tf_r1     = gdb_regs[KGDB_REGNUM_R0 +  1];
    124 	regs->tf_r2     = gdb_regs[KGDB_REGNUM_R0 +  2];
    125 	regs->tf_r3     = gdb_regs[KGDB_REGNUM_R0 +  3];
    126 	regs->tf_r4     = gdb_regs[KGDB_REGNUM_R0 +  4];
    127 	regs->tf_r5     = gdb_regs[KGDB_REGNUM_R0 +  5];
    128 	regs->tf_r6     = gdb_regs[KGDB_REGNUM_R0 +  6];
    129 	regs->tf_r7     = gdb_regs[KGDB_REGNUM_R0 +  7];
    130 	regs->tf_r8     = gdb_regs[KGDB_REGNUM_R0 +  8];
    131 	regs->tf_r9     = gdb_regs[KGDB_REGNUM_R0 +  9];
    132 	regs->tf_r10    = gdb_regs[KGDB_REGNUM_R0 + 10];
    133 	regs->tf_r11    = gdb_regs[KGDB_REGNUM_R0 + 11];
    134 	regs->tf_r12    = gdb_regs[KGDB_REGNUM_R0 + 12];
    135 	regs->tf_svc_sp = gdb_regs[KGDB_REGNUM_R0 + 13];
    136 	regs->tf_svc_lr = gdb_regs[KGDB_REGNUM_R0 + 14];
    137 	regs->tf_pc     = gdb_regs[KGDB_REGNUM_R0 + 15];
    138 
    139 	regs->tf_spsr = gdb_regs[KGDB_REGNUM_SPSR];
    140 }
    141 
    142 /*
    143  * Trap into kgdb to wait for debugger to connect,
    144  * noting on the console why nothing else is going on.
    145  */
    146 void
    147 kgdb_connect(int verbose)
    148 {
    149 
    150 	if (kgdb_dev == NODEV)
    151 		return;
    152 
    153 	if (verbose)
    154 		printf("kgdb waiting...");
    155 
    156 	__asm volatile(KBPT_ASM);
    157 
    158 	if (verbose)
    159 		printf("connected.\n");
    160 
    161 	kgdb_debug_panic = 1;
    162 }
    163 
    164 /*
    165  * Decide what to do on panic.
    166  * (This is called by panic, like Debugger())
    167  */
    168 void
    169 kgdb_panic(void)
    170 {
    171 
    172 	if (kgdb_dev != NODEV && kgdb_debug_panic) {
    173 		printf("entering kgdb\n");
    174 		kgdb_connect(kgdb_active == 0);
    175 	}
    176 }
    177