1 /* $OpenBSD: db_memrw.c,v 1.19 2024/02/23 18:19:03 cheloha Exp $ */
2 /* $NetBSD: db_memrw.c,v 1.6 1999/04/12 20:38:19 pk Exp $ */
3
4 /*
5 * Mach Operating System
6 * Copyright (c) 1991,1990 Carnegie Mellon University
7 * All Rights Reserved.
8 *
9 * Permission to use, copy, modify and distribute this software and its
10 * documentation is hereby granted, provided that both the copyright
11 * notice and this permission notice appear in all copies of the
12 * software, derivative works or modified versions, and any portions
13 * thereof, and that both notices appear in supporting documentation.
14 *
15 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
16 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
17 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
18 *
19 * Carnegie Mellon requests users of this software to return to
20 *
21 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
22 * School of Computer Science
23 * Carnegie Mellon University
24 * Pittsburgh PA 15213-3890
25 *
26 * any improvements or extensions that they make and grant Carnegie Mellon
27 * the rights to redistribute these changes.
28 *
29 * db_interface.c,v 2.4 1991/02/05 17:11:13 mrt (CMU)
30 */
31
32 /*
33 * Routines to read and write memory on behalf of the debugger, used
34 * by DDB.
35 */
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39
40 #include <uvm/uvm_extern.h>
41
42 #include <machine/db_machdep.h>
43
44 #include <ddb/db_access.h>
45
46 #define PG_LGFRAME 0xffc00000 /* large (4M) page frame mask */
47 #define PG_LGFRAME_PAE 0xffe00000 /* large (2M) page frame mask */
48
49 /*
50 * Read bytes from kernel address space for debugger.
51 */
52 void
db_read_bytes(vaddr_t addr,size_t size,void * datap)53 db_read_bytes(vaddr_t addr, size_t size, void *datap)
54 {
55 char *data = datap, *src;
56
57 src = (char *)addr;
58 while (size-- > 0)
59 *data++ = *src++;
60 }
61
62 /*
63 * Write bytes somewhere in the kernel text. Make the text
64 * pages writable temporarily.
65 */
66 static void
db_write_text(vaddr_t addr,size_t size,char * data)67 db_write_text(vaddr_t addr, size_t size, char *data)
68 {
69 vaddr_t pgva;
70 size_t limit;
71 uint32_t bits;
72 char *dst;
73
74 if (size == 0)
75 return;
76
77 dst = (char *)addr;
78
79 do {
80 /*
81 * Get the PTE for the page.
82 */
83 bits = pmap_pte_bits(addr);
84
85 if ((bits & PG_V) == 0) {
86 printf(" address %p not a valid page\n", dst);
87 return;
88 }
89
90 /*
91 * Get the VA for the page.
92 */
93 if (bits & PG_PS) {
94 if (cpu_pae)
95 pgva = (vaddr_t)dst & PG_LGFRAME_PAE;
96 else
97 pgva = (vaddr_t)dst & PG_LGFRAME;
98 } else
99 pgva = trunc_page((vaddr_t)dst);
100
101 /*
102 * Compute number of bytes that can be written
103 * with this mapping and subtract it from the
104 * total size.
105 */
106 #ifdef NBPD_L2
107 if (bits & PG_PS)
108 limit = NBPD_L2 - ((vaddr_t)dst & (NBPD_L2 - 1));
109 else
110 #endif
111 limit = PAGE_SIZE - ((vaddr_t)dst & PGOFSET);
112 if (limit > size)
113 limit = size;
114 size -= limit;
115
116 pmap_update_pg(pgva);
117 pmap_pte_setbits(addr, PG_RW, 0);
118
119 /*
120 * Page is now writable. Do as much access as we
121 * can in this page.
122 */
123 for (; limit > 0; limit--)
124 *dst++ = *data++;
125
126 /*
127 * Restore the old PTE.
128 */
129 pmap_update_pg(pgva);
130 pmap_pte_setbits(addr, bits, PG_RW);
131
132 } while (size != 0);
133 }
134
135 /*
136 * Write bytes to kernel address space for debugger.
137 */
138 void
db_write_bytes(vaddr_t addr,size_t size,void * datap)139 db_write_bytes(vaddr_t addr, size_t size, void *datap)
140 {
141 char *data = datap, *dst;
142 extern char etext;
143
144 if (addr >= VM_MIN_KERNEL_ADDRESS &&
145 addr < (vaddr_t)&etext) {
146 db_write_text(addr, size, data);
147 return;
148 }
149
150 dst = (char *)addr;
151
152 while (size-- > 0)
153 *dst++ = *data++;
154 }
155