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db_memrw.c revision 1.4 
      1 /*	$NetBSD: db_memrw.c,v 1.4 1994/11/28 19:33:08 gwr Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1994 Gordon W. Ross
      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  * 3. The name of the author may not be used to endorse or promote products
     16  *    derived from this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     28  */
     29 
     30 /*
     31  * Interface to the debugger for virtual memory read/write.
     32  * To write in the text segment, we have to first make
     33  * the page writable, do the write, then restore the PTE.
     34  * For reads, validate address first to avoid MMU trap.
     35  */
     36 
     37 #include <sys/param.h>
     38 #include <sys/proc.h>
     39 
     40 #include <vm/vm.h>
     41 
     42 #include <machine/db_machdep.h>
     43 #include <machine/pte.h>
     44 
     45 /*
     46  * Read one byte somewhere in the kernel.
     47  * It does not matter if this is slow. -gwr
     48  */
     49 static char
     50 db_read_data(src)
     51 	char *src;
     52 {
     53 	int		oldpte;
     54 	vm_offset_t pgva;
     55 	int ch;
     56 
     57 	pgva = sun3_trunc_page((long)src);
     58 	oldpte = get_pte(pgva);
     59 
     60 	if ((oldpte & PG_VALID) == 0) {
     61 		db_printf(" address 0x%x not a valid page\n", src);
     62 		return 0;
     63 	}
     64 	return (*src);
     65 }
     66 
     67 /*
     68  * Read bytes from kernel address space for debugger.
     69  * It does not matter if this is slow. -gwr
     70  */
     71 void
     72 db_read_bytes(addr, size, data)
     73 	vm_offset_t	addr;
     74 	register int	size;
     75 	register char	*data;
     76 {
     77 	char	*src, *limit;
     78 
     79 	src = (char *)addr;
     80 	limit = src + size;
     81 
     82 	while (src < limit) {
     83 		*data = db_read_data(src);
     84 		data++;
     85 		src++;
     86 	}
     87 }
     88 
     89 /*
     90  * Write one byte somewhere in kernel text.
     91  * It does not matter if this is slow. -gwr
     92  */
     93 static void
     94 db_write_text(dst, ch)
     95 	char *dst;
     96 	int ch;
     97 {
     98 	int		oldpte, tmppte;
     99 	vm_offset_t pgva;
    100 
    101 	pgva = sun3_trunc_page((long)dst);
    102 	oldpte = get_pte(pgva);
    103 
    104 	if ((oldpte & PG_VALID) == 0) {
    105 		db_printf(" address 0x%x not a valid page\n", dst);
    106 		return;
    107 	}
    108 
    109 	tmppte = oldpte | PG_WRITE;
    110 	set_pte(pgva, tmppte);
    111 
    112 	*dst = (char) ch;
    113 
    114 	set_pte(pgva, oldpte);
    115 }
    116 
    117 /*
    118  * Write one byte somewhere outside kernel text.
    119  * It does not matter if this is slow. -gwr
    120  */
    121 static void
    122 db_write_data(dst, ch)
    123 	char *dst;
    124 	int ch;
    125 {
    126 	int		oldpte;
    127 	vm_offset_t pgva;
    128 
    129 	pgva = sun3_trunc_page((long)dst);
    130 	oldpte = get_pte(pgva);
    131 
    132 	if ((oldpte & (PG_VALID | PG_WRITE)) == 0) {
    133 		db_printf(" address 0x%x not a valid page\n", dst);
    134 		return;
    135 	}
    136 	*dst = (char) ch;
    137 }
    138 
    139 /*
    140  * Write bytes to kernel address space for debugger.
    141  */
    142 void
    143 db_write_bytes(addr, size, data)
    144 	vm_offset_t	addr;
    145 	int	size;
    146 	char	*data;
    147 {
    148 	extern char	start[], etext[] ;
    149 	char	*dst, *limit;
    150 
    151 	dst = (char *)addr;
    152 	limit = dst + size;
    153 
    154 	while (dst < limit) {
    155 		if ((dst >= start) && (dst < etext))
    156 			db_write_text(dst, *data);
    157 		else
    158 			db_write_data(dst, *data);
    159 		dst++;
    160 		data++;
    161 	}
    162 }
    163