RTEMS: cpukit/dtc/libfdt/libfdt_internal.h Source File

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libfdt_internal.h
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#define FDT_SW_MAGIC (~FDT_MAGIC)
50
51/**********************************************************************/
52/* Checking controls */
53/**********************************************************************/
54
55#ifndef FDT_ASSUME_MASK
56#define FDT_ASSUME_MASK 0
57#endif
58
59/*
60 * Defines assumptions which can be enabled. Each of these can be enabled
61 * individually. For maximum saftey, don't enable any assumptions!
62 *
63 * For minimal code size and no safety, use ASSUME_PERFECT at your own risk.
64 * You should have another method of validating the device tree, such as a
65 * signature or hash check before using libfdt.
66 *
67 * For situations where security is not a concern it may be safe to enable
68 * ASSUME_SANE.
69 */
70enum {
71 /*
72 * This does essentially no checks. Only the latest device-tree
73 * version is correctly handled. Inconsistencies or errors in the device
74 * tree may cause undefined behaviour or crashes. Invalid parameters
75 * passed to libfdt may do the same.
76 *
77 * If an error occurs when modifying the tree it may leave the tree in
78 * an intermediate (but valid) state. As an example, adding a property
79 * where there is insufficient space may result in the property name
80 * being added to the string table even though the property itself is
81 * not added to the struct section.
82 *
83 * Only use this if you have a fully validated device tree with
84 * the latest supported version and wish to minimise code size.
85 */
86 ASSUME_PERFECT = 0xff,
87
88 /*
89 * This assumes that the device tree is sane. i.e. header metadata
90 * and basic hierarchy are correct.
91 *
92 * With this assumption enabled, normal device trees produced by libfdt
93 * and the compiler should be handled safely. Malicious device trees and
94 * complete garbage may cause libfdt to behave badly or crash.
95 *
96 * Note: Only checks that relate exclusively to the device tree itself
97 * (not the parameters passed to libfdt) are disabled by this
98 * assumption. This includes checking headers, tags and the like.
99 */
100 ASSUME_VALID_DTB = 1 << 0,
101
102 /*
103 * This builds on ASSUME_VALID_DTB and further assumes that libfdt
104 * functions are called with valid parameters, i.e. not trigger
105 * FDT_ERR_BADOFFSET or offsets that are out of bounds. It disables any
106 * extensive checking of parameters and the device tree, making various
107 * assumptions about correctness.
108 *
109 * It doesn't make sense to enable this assumption unless
110 * ASSUME_VALID_DTB is also enabled.
111 */
112 ASSUME_VALID_INPUT = 1 << 1,
113
114 /*
115 * This disables checks for device-tree version and removes all code
116 * which handles older versions.
117 *
118 * Only enable this if you know you have a device tree with the latest
119 * version.
120 */
121 ASSUME_LATEST = 1 << 2,
122
123 /*
124 * This assume that it is OK for a failed additional to the device tree
125 * due to lack of space or some other problem can skip any rollback
126 * steps (such as dropping the property name from the string table).
127 * This is safe to enable in most circumstances, even though it may
128 * leave the tree in a sub-optimal state.
129 */
130 ASSUME_NO_ROLLBACK = 1 << 3,
131
132 /*
133 * This assumes that the device tree components appear in the correct
134 * order. As such it disables a check in fdt_open_into() and removes the
135 * ability to fix the problem there. This is safe if you know that the
136 * device tree is correctly ordered. See fdt_blocks_misordered_().
137 */
138 ASSUME_LIBFDT_ORDER = 1 << 4,
139};
140
147static inline bool can_assume_(int mask)
148{
149 return FDT_ASSUME_MASK & mask;
150}
151
153#define can_assume(_assume) can_assume_(ASSUME_ ## _assume)
154
155#endif /* LIBFDT_INTERNAL_H */
fdt_reserve_entry
Definition: fdt.h:31