Annotation of sys/arch/hp300/hp300/db_memrw.c, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: db_memrw.c,v 1.9 2002/03/14 03:15:52 millert Exp $ */
2: /* $NetBSD: db_memrw.c,v 1.5 1997/06/10 18:48:47 veego Exp $ */
3:
4: /*-
5: * Copyright (c) 1996 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 REGENTS OR CONTRIBUTORS BE
31: * 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 from sun3 version for hp300 (and probably other m68ks, too)
56: * by Jason R. Thorpe <thorpej@NetBSD.ORG>.
57: */
58:
59: #include <sys/param.h>
60: #include <sys/systm.h>
61: #include <sys/proc.h>
62:
63: #include <uvm/uvm_extern.h>
64:
65: #include <machine/pte.h>
66: #include <machine/db_machdep.h>
67: #include <machine/cpu.h>
68:
69: #include <ddb/db_access.h>
70:
71: static void db_write_text(db_addr_t, size_t, char *);
72:
73: /*
74: * Read bytes from kernel address space for debugger.
75: * This used to check for valid PTEs, but now that
76: * traps in DDB work correctly, "Just Do It!"
77: */
78: void
79: db_read_bytes(addr, size, data)
80: db_addr_t addr;
81: size_t size;
82: char *data;
83: {
84: char *src = (char *)addr;
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: --size;
98: *data++ = *src++;
99: }
100: }
101:
102: /*
103: * Write bytes somewhere in kernel text.
104: * Makes text page writable temporarily.
105: * We're probably a little to cache-paranoid.
106: */
107: static void
108: db_write_text(addr, size, data)
109: db_addr_t addr;
110: size_t size;
111: char *data;
112: {
113: char *dst, *odst;
114: pt_entry_t *pte, oldpte, tmppte;
115: vaddr_t pgva;
116: int limit;
117:
118: if (size == 0)
119: return;
120:
121: dst = (char *)addr;
122:
123: do {
124: /*
125: * Get the VA for the page.
126: */
127: pgva = trunc_page((vaddr_t)dst);
128:
129: /*
130: * Save this destination address, for TLB
131: * flush.
132: */
133: odst = dst;
134:
135: /*
136: * Compute number of bytes that can be written
137: * with this mapping and subtract it from the
138: * total size.
139: */
140: limit = NBPG - ((u_long)dst & PGOFSET);
141: if (limit > size)
142: limit = size;
143: size -= limit;
144:
145: #ifdef M68K_MMU_HP
146: /*
147: * Flush the supervisor side of the VAC to
148: * prevent a cache hit on the old, read-only PTE.
149: * XXX Is this really necessary, or am I just
150: * paranoid?
151: */
152: if (ectype == EC_VIRT)
153: DCIS();
154: #endif
155:
156: /*
157: * Make the page writable. Note the mapping is
158: * cache-inhibited to save hair.
159: */
160: pte = kvtopte(pgva);
161: oldpte = *pte;
162:
163: if ((oldpte & PG_V) == 0) {
164: printf(" address %p not a valid page\n", dst);
165: return;
166: }
167:
168: tmppte = (oldpte & ~PG_RO) | PG_RW | PG_CI;
169: *pte = tmppte;
170: TBIS((vaddr_t)odst);
171:
172: /*
173: * Page is now writable. Do as much access as we
174: * can in this page.
175: */
176: for (; limit > 0; limit--)
177: *dst++ = *data++;
178:
179: /*
180: * Restore the old PTE.
181: */
182: *pte = oldpte;
183: TBIS((vaddr_t)odst);
184: } while (size != 0);
185:
186: /*
187: * Invalidate the instruction cache so our changes
188: * take effect.
189: */
190: ICIA();
191: }
192:
193: /*
194: * Write bytes to kernel address space for debugger.
195: */
196: extern char kernel_text[], etext[];
197: void
198: db_write_bytes(addr, size, data)
199: db_addr_t addr;
200: size_t size;
201: char *data;
202: {
203: char *dst = (char *)addr;
204:
205: /* If any part is in kernel text, use db_write_text() */
206: if ((dst < etext) && ((dst + size) > kernel_text)) {
207: db_write_text(addr, size, data);
208: return;
209: }
210:
211: if (size == 4) {
212: *((int *)dst) = *((int *)data);
213: return;
214: }
215:
216: if (size == 2) {
217: *((short *)dst) = *((short *)data);
218: return;
219: }
220:
221: while (size > 0) {
222: --size;
223: *dst++ = *data++;
224: }
225: }
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