Annotation of sys/arch/amd64/amd64/db_memrw.c, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: db_memrw.c,v 1.3 2005/10/21 18:55:00 martin Exp $ */
2: /* $NetBSD: db_memrw.c,v 1.1 2003/04/26 18:39:27 fvdl Exp $ */
3:
4: /*-
5: * Copyright (c) 1996, 2000 The NetBSD Foundation, Inc.
6: * All rights reserved.
7: *
8: * This code is derived from software contributed to The NetBSD Foundation
9: * by Gordon W. Ross and Jason R. Thorpe.
10: *
11: * Redistribution and use in source and binary forms, with or without
12: * modification, are permitted provided that the following conditions
13: * are met:
14: * 1. Redistributions of source code must retain the above copyright
15: * notice, this list of conditions and the following disclaimer.
16: * 2. Redistributions in binary form must reproduce the above copyright
17: * notice, this list of conditions and the following disclaimer in the
18: * documentation and/or other materials provided with the distribution.
19: * 3. All advertising materials mentioning features or use of this software
20: * must display the following acknowledgement:
21: * This product includes software developed by the NetBSD
22: * Foundation, Inc. and its contributors.
23: * 4. Neither the name of The NetBSD Foundation nor the names of its
24: * contributors may be used to endorse or promote products derived
25: * from this software without specific prior written permission.
26: *
27: * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28: * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29: * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30: * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31: * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37: * POSSIBILITY OF SUCH DAMAGE.
38: */
39:
40: /*
41: * Interface to the debugger for virtual memory read/write.
42: * This file is shared by DDB and KGDB, and must work even
43: * when only KGDB is included (thus no db_printf calls).
44: *
45: * To write in the text segment, we have to first make
46: * the page writable, do the write, then restore the PTE.
47: * For writes outside the text segment, and all reads,
48: * just do the access -- if it causes a fault, the debugger
49: * will recover with a longjmp to an appropriate place.
50: *
51: * ALERT! If you want to access device registers with a
52: * specific size, then the read/write functions have to
53: * make sure to do the correct sized pointer access.
54: *
55: * Modified for i386 from hp300 version by
56: * Jason R. Thorpe <thorpej@zembu.com>.
57: *
58: * Basic copy to amd64 by fvdl.
59: */
60:
61: #include <sys/param.h>
62: #include <sys/proc.h>
63: #include <sys/systm.h>
64:
65: #include <uvm/uvm_extern.h>
66:
67: #include <machine/db_machdep.h>
68:
69: #include <ddb/db_access.h>
70:
71: /*
72: * Read bytes from kernel address space for debugger.
73: */
74: void
75: db_read_bytes(vaddr_t addr, size_t size, char *data)
76: {
77: char *src;
78:
79: src = (char *)addr;
80:
81: if (size == 8) {
82: *((long *)data) = *((long *)src);
83: return;
84: }
85:
86: if (size == 4) {
87: *((int *)data) = *((int *)src);
88: return;
89: }
90:
91: if (size == 2) {
92: *((short *)data) = *((short *)src);
93: return;
94: }
95:
96: while (size-- > 0)
97: *data++ = *src++;
98: }
99:
100: /*
101: * Write bytes somewhere in the kernel text. Make the text
102: * pages writable temporarily.
103: */
104: static void
105: db_write_text(vaddr_t addr, size_t size, char *data)
106: {
107: pt_entry_t *pte, oldpte, tmppte;
108: vaddr_t pgva;
109: size_t limit;
110: char *dst;
111:
112: if (size == 0)
113: return;
114:
115: dst = (char *)addr;
116:
117: do {
118: /*
119: * Get the PTE for the page.
120: */
121: pte = kvtopte(addr);
122: oldpte = *pte;
123:
124: if ((oldpte & PG_V) == 0) {
125: printf(" address %p not a valid page\n", dst);
126: return;
127: }
128:
129: /*
130: * Get the VA for the page.
131: */
132: if (oldpte & PG_PS)
133: pgva = (vaddr_t)dst & PG_LGFRAME;
134: else
135: pgva = trunc_page((vaddr_t)dst);
136:
137: /*
138: * Compute number of bytes that can be written
139: * with this mapping and subtract it from the
140: * total size.
141: */
142: if (oldpte & PG_PS)
143: limit = NBPD_L2 - ((vaddr_t)dst & (NBPD_L2 - 1));
144: else
145: limit = PAGE_SIZE - ((vaddr_t)dst & PGOFSET);
146: if (limit > size)
147: limit = size;
148: size -= limit;
149:
150: tmppte = (oldpte & ~PG_KR) | PG_KW;
151: *pte = tmppte;
152: pmap_update_pg(pgva);
153:
154: /*
155: * Page is now writable. Do as much access as we
156: * can in this page.
157: */
158: for (; limit > 0; limit--)
159: *dst++ = *data++;
160:
161: /*
162: * Restore the old PTE.
163: */
164: *pte = oldpte;
165:
166: pmap_update_pg(pgva);
167:
168: } while (size != 0);
169: }
170:
171: /*
172: * Write bytes to kernel address space for debugger.
173: */
174: void
175: db_write_bytes(vaddr_t addr, size_t size, char *data)
176: {
177: extern char etext;
178: char *dst;
179:
180: dst = (char *)addr;
181:
182: /* If any part is in kernel text, use db_write_text() */
183: if (addr >= KERNBASE && addr < (vaddr_t)&etext) {
184: db_write_text(addr, size, data);
185: return;
186: }
187:
188: dst = (char *)addr;
189:
190: if (size == 8) {
191: *((long *)dst) = *((long *)data);
192: return;
193: }
194:
195: if (size == 4) {
196: *((int *)dst) = *((int *)data);
197: return;
198: }
199:
200: if (size == 2) {
201: *((short *)dst) = *((short *)data);
202: return;
203: }
204:
205: while (size-- > 0)
206: *dst++ = *data++;
207: }
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