1/*	$OpenBSD: db_memrw.c,v 1.3 2024/02/23 18:19:03 cheloha 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 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33#include <sys/param.h>
34#include <sys/systm.h>
35
36#include <uvm/uvm_extern.h>
37
38#include <machine/cpufunc.h>
39#include <machine/db_machdep.h>
40#include <machine/pmap.h>
41#include <machine/pte.h>
42
43#include <ddb/db_access.h>
44
45/*
46 * Read bytes from kernel address space for debugger.
47 */
48void
49db_read_bytes(vaddr_t addr, size_t size, void *datap)
50{
51	char *data = datap, *src;
52
53	src = (char *)addr;
54
55	if (size == 8) {
56		*((long *)data) = *((long *)src);
57		return;
58	}
59
60	if (size == 4) {
61		*((int *)data) = *((int *)src);
62		return;
63	}
64
65	if (size == 2) {
66		*((short *)data) = *((short *)src);
67		return;
68	}
69
70	while (size-- > 0)
71		*data++ = *src++;
72}
73
74/*
75 * Write bytes somewhere in the kernel text.  Make the text
76 * pages writable temporarily.
77 */
78void
79db_write_text(vaddr_t addr, size_t size, char *data)
80{
81	struct pte *pte;
82	uint64_t old_pte_lo;
83	vaddr_t pgva;
84	size_t limit;
85	char *dst;
86
87	if (size == 0)
88		return;
89
90	dst = (char *)addr;
91
92	do {
93		pte = pmap_get_kernel_pte((vaddr_t)dst);
94		if (pte == NULL) {
95			printf(" address %p not a valid page\n", dst);
96			return;
97		}
98
99		/*
100		 * Compute number of bytes that can be written
101		 * with this mapping and subtract it from the
102		 * total size.
103		 */
104		pgva = trunc_page((vaddr_t)dst);
105		limit = PAGE_SIZE - ((vaddr_t)dst & PGOFSET);
106		if (limit > size)
107			limit = size;
108		size -= limit;
109
110		/*
111		 * Gain write access to the page.  We don't need
112		 * tlbie to "add access authorities" (Power ISA 3.0
113		 * III 5.10.1.2 Modifying a Translation Table Entry).
114		 */
115		old_pte_lo = pte->pte_lo;
116		pte->pte_lo = (old_pte_lo & ~PTE_PP) | PTE_RW;
117		ptesync();
118
119		for (; limit > 0; limit--)
120			*dst++ = *data++;
121
122		/* Restore the old PTE. */
123		pte->pte_lo = old_pte_lo;
124		ptesync();
125		tlbie(pgva);
126		eieio();
127		tlbsync();
128		ptesync();
129
130	} while (size != 0);
131
132	__syncicache((void *)addr, limit);
133}
134
135/*
136 * Write bytes to kernel address space for debugger.
137 */
138void
139db_write_bytes(vaddr_t addr, size_t size, void *datap)
140{
141	extern char _start[], _etext[];
142	char *data = datap, *dst;
143
144	/* If any part is in kernel text, use db_write_text() */
145	if (addr >= (vaddr_t)_start && addr < (vaddr_t)_etext) {
146		db_write_text(addr, size, data);
147		return;
148	}
149
150	dst = (char *)addr;
151
152	if (size == 8) {
153		*((long *)dst) = *((long *)data);
154		return;
155	}
156
157	if (size == 4) {
158		*((int *)dst) = *((int *)data);
159		return;
160	}
161
162	if (size == 2) {
163		*((short *)dst) = *((short *)data);
164		return;
165	}
166
167	while (size-- > 0)
168		*dst++ = *data++;
169}
170