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1/* SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) */
2#ifndef LIBFDT_INTERNAL_H
3#define LIBFDT_INTERNAL_H
4/*
5 * libfdt - Flat Device Tree manipulation
6 * Copyright (C) 2006 David Gibson, IBM Corporation.
7 */
8#include <fdt.h>
9
10#define FDT_ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1))
11#define FDT_TAGALIGN(x) (FDT_ALIGN((x), FDT_TAGSIZE))
12
13int32_t fdt_ro_probe_(const void *fdt);
14#define FDT_RO_PROBE(fdt) \
15 { \
16 int32_t totalsize_; \
17 if ((totalsize_ = fdt_ro_probe_(fdt)) < 0) \
18 return totalsize_; \
19 }
20
21int fdt_check_node_offset_(const void *fdt, int offset);
22int fdt_check_prop_offset_(const void *fdt, int offset);
23const char *fdt_find_string_(const char *strtab, int tabsize, const char *s);
24int fdt_node_end_offset_(void *fdt, int nodeoffset);
25
26static inline const void *fdt_offset_ptr_(const void *fdt, int offset)
27{
28 return (const char *)fdt + fdt_off_dt_struct(fdt) + offset;
29}
30
31static inline void *fdt_offset_ptr_w_(void *fdt, int offset)
32{
33 return (void *)(uintptr_t)fdt_offset_ptr_(fdt, offset);
34}
35
36static inline const struct fdt_reserve_entry *fdt_mem_rsv_(const void *fdt, int n)
37{
38 const struct fdt_reserve_entry *rsv_table =
39 (const struct fdt_reserve_entry *)
40 ((const char *)fdt + fdt_off_mem_rsvmap(fdt));
41
42 return rsv_table + n;
43}
44static inline struct fdt_reserve_entry *fdt_mem_rsv_w_(void *fdt, int n)
45{
46 return (void *)(uintptr_t)fdt_mem_rsv_(fdt, n);
47}
48
49/*
50 * Internal helpers to access tructural elements of the device tree
51 * blob (rather than for exaple reading integers from within property
52 * values). We assume that we are either given a naturally aligned
53 * address for the platform or if we are not, we are on a platform
54 * where unaligned memory reads will be handled in a graceful manner.
55 * If not the external helpers fdtXX_ld() from libfdt.h can be used
56 * instead.
57 */
58static inline uint32_t fdt32_ld_(const fdt32_t *p)
59{
60 return fdt32_to_cpu(*p);
61}
62
63static inline uint64_t fdt64_ld_(const fdt64_t *p)
64{
65 return fdt64_to_cpu(*p);
66}
67
68#define FDT_SW_MAGIC (~FDT_MAGIC)
69
70/**********************************************************************/
71/* Checking controls */
72/**********************************************************************/
73
74#ifndef FDT_ASSUME_MASK
75#define FDT_ASSUME_MASK 0
76#endif
77
78/*
79 * Defines assumptions which can be enabled. Each of these can be enabled
80 * individually. For maximum safety, don't enable any assumptions!
81 *
82 * For minimal code size and no safety, use ASSUME_PERFECT at your own risk.
83 * You should have another method of validating the device tree, such as a
84 * signature or hash check before using libfdt.
85 *
86 * For situations where security is not a concern it may be safe to enable
87 * ASSUME_SANE.
88 */
89enum {
90 /*
91 * This does essentially no checks. Only the latest device-tree
92 * version is correctly handled. Inconsistencies or errors in the device
93 * tree may cause undefined behaviour or crashes. Invalid parameters
94 * passed to libfdt may do the same.
95 *
96 * If an error occurs when modifying the tree it may leave the tree in
97 * an intermediate (but valid) state. As an example, adding a property
98 * where there is insufficient space may result in the property name
99 * being added to the string table even though the property itself is
100 * not added to the struct section.
101 *
102 * Only use this if you have a fully validated device tree with
103 * the latest supported version and wish to minimise code size.
104 */
105 ASSUME_PERFECT = 0xff,
106
107 /*
108 * This assumes that the device tree is sane. i.e. header metadata
109 * and basic hierarchy are correct.
110 *
111 * With this assumption enabled, normal device trees produced by libfdt
112 * and the compiler should be handled safely. Malicious device trees and
113 * complete garbage may cause libfdt to behave badly or crash. Truncated
114 * device trees (e.g. those only partially loaded) can also cause
115 * problems.
116 *
117 * Note: Only checks that relate exclusively to the device tree itself
118 * (not the parameters passed to libfdt) are disabled by this
119 * assumption. This includes checking headers, tags and the like.
120 */
121 ASSUME_VALID_DTB = 1 << 0,
122
123 /*
124 * This builds on ASSUME_VALID_DTB and further assumes that libfdt
125 * functions are called with valid parameters, i.e. not trigger
126 * FDT_ERR_BADOFFSET or offsets that are out of bounds. It disables any
127 * extensive checking of parameters and the device tree, making various
128 * assumptions about correctness.
129 *
130 * It doesn't make sense to enable this assumption unless
131 * ASSUME_VALID_DTB is also enabled.
132 */
133 ASSUME_VALID_INPUT = 1 << 1,
134
135 /*
136 * This disables checks for device-tree version and removes all code
137 * which handles older versions.
138 *
139 * Only enable this if you know you have a device tree with the latest
140 * version.
141 */
142 ASSUME_LATEST = 1 << 2,
143
144 /*
145 * This assumes that it is OK for a failed addition to the device tree,
146 * due to lack of space or some other problem, to skip any rollback
147 * steps (such as dropping the property name from the string table).
148 * This is safe to enable in most circumstances, even though it may
149 * leave the tree in a sub-optimal state.
150 */
151 ASSUME_NO_ROLLBACK = 1 << 3,
152
153 /*
154 * This assumes that the device tree components appear in a 'convenient'
155 * order, i.e. the memory reservation block first, then the structure
156 * block and finally the string block.
157 *
158 * This order is not specified by the device-tree specification,
159 * but is expected by libfdt. The device-tree compiler always created
160 * device trees with this order.
161 *
162 * This assumption disables a check in fdt_open_into() and removes the
163 * ability to fix the problem there. This is safe if you know that the
164 * device tree is correctly ordered. See fdt_blocks_misordered_().
165 */
166 ASSUME_LIBFDT_ORDER = 1 << 4,
167
168 /*
169 * This assumes that libfdt itself does not have any internal bugs. It
170 * drops certain checks that should never be needed unless libfdt has an
171 * undiscovered bug.
172 *
173 * This can generally be considered safe to enable.
174 */
175 ASSUME_LIBFDT_FLAWLESS = 1 << 5,
176};
177
178/**
179 * can_assume_() - check if a particular assumption is enabled
180 *
181 * @mask: Mask to check (ASSUME_...)
182 * @return true if that assumption is enabled, else false
183 */
184static inline bool can_assume_(int mask)
185{
186 return FDT_ASSUME_MASK & mask;
187}
188
189/** helper macros for checking assumptions */
190#define can_assume(_assume) can_assume_(ASSUME_ ## _assume)
191
192#endif /* LIBFDT_INTERNAL_H */
1#ifndef _LIBFDT_INTERNAL_H
2#define _LIBFDT_INTERNAL_H
3/*
4 * libfdt - Flat Device Tree manipulation
5 * Copyright (C) 2006 David Gibson, IBM Corporation.
6 *
7 * libfdt is dual licensed: you can use it either under the terms of
8 * the GPL, or the BSD license, at your option.
9 *
10 * a) This library is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
14 *
15 * This library is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public
21 * License along with this library; if not, write to the Free
22 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
23 * MA 02110-1301 USA
24 *
25 * Alternatively,
26 *
27 * b) Redistribution and use in source and binary forms, with or
28 * without modification, are permitted provided that the following
29 * conditions are met:
30 *
31 * 1. Redistributions of source code must retain the above
32 * copyright notice, this list of conditions and the following
33 * disclaimer.
34 * 2. Redistributions in binary form must reproduce the above
35 * copyright notice, this list of conditions and the following
36 * disclaimer in the documentation and/or other materials
37 * provided with the distribution.
38 *
39 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
40 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
41 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
42 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
43 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
44 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
49 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
50 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
51 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
52 */
53#include <fdt.h>
54
55#define FDT_ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1))
56#define FDT_TAGALIGN(x) (FDT_ALIGN((x), FDT_TAGSIZE))
57
58#define FDT_CHECK_HEADER(fdt) \
59 { \
60 int err; \
61 if ((err = fdt_check_header(fdt)) != 0) \
62 return err; \
63 }
64
65int _fdt_check_node_offset(const void *fdt, int offset);
66int _fdt_check_prop_offset(const void *fdt, int offset);
67const char *_fdt_find_string(const char *strtab, int tabsize, const char *s);
68int _fdt_node_end_offset(void *fdt, int nodeoffset);
69
70static inline const void *_fdt_offset_ptr(const void *fdt, int offset)
71{
72 return (const char *)fdt + fdt_off_dt_struct(fdt) + offset;
73}
74
75static inline void *_fdt_offset_ptr_w(void *fdt, int offset)
76{
77 return (void *)(uintptr_t)_fdt_offset_ptr(fdt, offset);
78}
79
80static inline const struct fdt_reserve_entry *_fdt_mem_rsv(const void *fdt, int n)
81{
82 const struct fdt_reserve_entry *rsv_table =
83 (const struct fdt_reserve_entry *)
84 ((const char *)fdt + fdt_off_mem_rsvmap(fdt));
85
86 return rsv_table + n;
87}
88static inline struct fdt_reserve_entry *_fdt_mem_rsv_w(void *fdt, int n)
89{
90 return (void *)(uintptr_t)_fdt_mem_rsv(fdt, n);
91}
92
93#define FDT_SW_MAGIC (~FDT_MAGIC)
94
95#endif /* _LIBFDT_INTERNAL_H */