112869ecdSRob Herring /* SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) */
29130ba88SRob Herring #ifndef LIBFDT_INTERNAL_H
39130ba88SRob Herring #define LIBFDT_INTERNAL_H
49fffb55fSDavid Gibson /*
59fffb55fSDavid Gibson * libfdt - Flat Device Tree manipulation
69fffb55fSDavid Gibson * Copyright (C) 2006 David Gibson, IBM Corporation.
79fffb55fSDavid Gibson */
89fffb55fSDavid Gibson #include <fdt.h>
99fffb55fSDavid Gibson
109fffb55fSDavid Gibson #define FDT_ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1))
119fffb55fSDavid Gibson #define FDT_TAGALIGN(x) (FDT_ALIGN((x), FDT_TAGSIZE))
129fffb55fSDavid Gibson
130cec114eSRob Herring int32_t fdt_ro_probe_(const void *fdt);
14f858927fSRob Herring #define FDT_RO_PROBE(fdt) \
159fffb55fSDavid Gibson { \
160cec114eSRob Herring int32_t totalsize_; \
170cec114eSRob Herring if ((totalsize_ = fdt_ro_probe_(fdt)) < 0) \
180cec114eSRob Herring return totalsize_; \
199fffb55fSDavid Gibson }
209fffb55fSDavid Gibson
219130ba88SRob Herring int fdt_check_node_offset_(const void *fdt, int offset);
229130ba88SRob Herring int fdt_check_prop_offset_(const void *fdt, int offset);
239130ba88SRob Herring const char *fdt_find_string_(const char *strtab, int tabsize, const char *s);
249130ba88SRob Herring int fdt_node_end_offset_(void *fdt, int nodeoffset);
259fffb55fSDavid Gibson
fdt_offset_ptr_(const void * fdt,int offset)269130ba88SRob Herring static inline const void *fdt_offset_ptr_(const void *fdt, int offset)
279fffb55fSDavid Gibson {
289fffb55fSDavid Gibson return (const char *)fdt + fdt_off_dt_struct(fdt) + offset;
299fffb55fSDavid Gibson }
309fffb55fSDavid Gibson
fdt_offset_ptr_w_(void * fdt,int offset)319130ba88SRob Herring static inline void *fdt_offset_ptr_w_(void *fdt, int offset)
329fffb55fSDavid Gibson {
339130ba88SRob Herring return (void *)(uintptr_t)fdt_offset_ptr_(fdt, offset);
349fffb55fSDavid Gibson }
359fffb55fSDavid Gibson
fdt_mem_rsv_(const void * fdt,int n)369130ba88SRob Herring static inline const struct fdt_reserve_entry *fdt_mem_rsv_(const void *fdt, int n)
379fffb55fSDavid Gibson {
389fffb55fSDavid Gibson const struct fdt_reserve_entry *rsv_table =
399fffb55fSDavid Gibson (const struct fdt_reserve_entry *)
409fffb55fSDavid Gibson ((const char *)fdt + fdt_off_mem_rsvmap(fdt));
419fffb55fSDavid Gibson
429fffb55fSDavid Gibson return rsv_table + n;
439fffb55fSDavid Gibson }
fdt_mem_rsv_w_(void * fdt,int n)449130ba88SRob Herring static inline struct fdt_reserve_entry *fdt_mem_rsv_w_(void *fdt, int n)
459fffb55fSDavid Gibson {
469130ba88SRob Herring return (void *)(uintptr_t)fdt_mem_rsv_(fdt, n);
479fffb55fSDavid Gibson }
489fffb55fSDavid Gibson
49*79edff12SRob Herring /*
50*79edff12SRob Herring * Internal helpers to access tructural elements of the device tree
51*79edff12SRob Herring * blob (rather than for exaple reading integers from within property
52*79edff12SRob Herring * values). We assume that we are either given a naturally aligned
53*79edff12SRob Herring * address for the platform or if we are not, we are on a platform
54*79edff12SRob Herring * where unaligned memory reads will be handled in a graceful manner.
55*79edff12SRob Herring * If not the external helpers fdtXX_ld() from libfdt.h can be used
56*79edff12SRob Herring * instead.
57*79edff12SRob Herring */
fdt32_ld_(const fdt32_t * p)58*79edff12SRob Herring static inline uint32_t fdt32_ld_(const fdt32_t *p)
59*79edff12SRob Herring {
60*79edff12SRob Herring return fdt32_to_cpu(*p);
61*79edff12SRob Herring }
62*79edff12SRob Herring
fdt64_ld_(const fdt64_t * p)63*79edff12SRob Herring static inline uint64_t fdt64_ld_(const fdt64_t *p)
64*79edff12SRob Herring {
65*79edff12SRob Herring return fdt64_to_cpu(*p);
66*79edff12SRob Herring }
67*79edff12SRob Herring
689fffb55fSDavid Gibson #define FDT_SW_MAGIC (~FDT_MAGIC)
699fffb55fSDavid Gibson
70d047cd8aSRob Herring /**********************************************************************/
71d047cd8aSRob Herring /* Checking controls */
72d047cd8aSRob Herring /**********************************************************************/
73d047cd8aSRob Herring
74d047cd8aSRob Herring #ifndef FDT_ASSUME_MASK
75d047cd8aSRob Herring #define FDT_ASSUME_MASK 0
76d047cd8aSRob Herring #endif
77d047cd8aSRob Herring
78d047cd8aSRob Herring /*
79d047cd8aSRob Herring * Defines assumptions which can be enabled. Each of these can be enabled
80d047cd8aSRob Herring * individually. For maximum safety, don't enable any assumptions!
81d047cd8aSRob Herring *
82d047cd8aSRob Herring * For minimal code size and no safety, use ASSUME_PERFECT at your own risk.
83d047cd8aSRob Herring * You should have another method of validating the device tree, such as a
84d047cd8aSRob Herring * signature or hash check before using libfdt.
85d047cd8aSRob Herring *
86d047cd8aSRob Herring * For situations where security is not a concern it may be safe to enable
87d047cd8aSRob Herring * ASSUME_SANE.
88d047cd8aSRob Herring */
89d047cd8aSRob Herring enum {
90d047cd8aSRob Herring /*
91d047cd8aSRob Herring * This does essentially no checks. Only the latest device-tree
92d047cd8aSRob Herring * version is correctly handled. Inconsistencies or errors in the device
93d047cd8aSRob Herring * tree may cause undefined behaviour or crashes. Invalid parameters
94d047cd8aSRob Herring * passed to libfdt may do the same.
95d047cd8aSRob Herring *
96d047cd8aSRob Herring * If an error occurs when modifying the tree it may leave the tree in
97d047cd8aSRob Herring * an intermediate (but valid) state. As an example, adding a property
98d047cd8aSRob Herring * where there is insufficient space may result in the property name
99d047cd8aSRob Herring * being added to the string table even though the property itself is
100d047cd8aSRob Herring * not added to the struct section.
101d047cd8aSRob Herring *
102d047cd8aSRob Herring * Only use this if you have a fully validated device tree with
103d047cd8aSRob Herring * the latest supported version and wish to minimise code size.
104d047cd8aSRob Herring */
105d047cd8aSRob Herring ASSUME_PERFECT = 0xff,
106d047cd8aSRob Herring
107d047cd8aSRob Herring /*
108d047cd8aSRob Herring * This assumes that the device tree is sane. i.e. header metadata
109d047cd8aSRob Herring * and basic hierarchy are correct.
110d047cd8aSRob Herring *
111d047cd8aSRob Herring * With this assumption enabled, normal device trees produced by libfdt
112d047cd8aSRob Herring * and the compiler should be handled safely. Malicious device trees and
113d047cd8aSRob Herring * complete garbage may cause libfdt to behave badly or crash. Truncated
114d047cd8aSRob Herring * device trees (e.g. those only partially loaded) can also cause
115d047cd8aSRob Herring * problems.
116d047cd8aSRob Herring *
117d047cd8aSRob Herring * Note: Only checks that relate exclusively to the device tree itself
118d047cd8aSRob Herring * (not the parameters passed to libfdt) are disabled by this
119d047cd8aSRob Herring * assumption. This includes checking headers, tags and the like.
120d047cd8aSRob Herring */
121d047cd8aSRob Herring ASSUME_VALID_DTB = 1 << 0,
122d047cd8aSRob Herring
123d047cd8aSRob Herring /*
124d047cd8aSRob Herring * This builds on ASSUME_VALID_DTB and further assumes that libfdt
125d047cd8aSRob Herring * functions are called with valid parameters, i.e. not trigger
126d047cd8aSRob Herring * FDT_ERR_BADOFFSET or offsets that are out of bounds. It disables any
127d047cd8aSRob Herring * extensive checking of parameters and the device tree, making various
128d047cd8aSRob Herring * assumptions about correctness.
129d047cd8aSRob Herring *
130d047cd8aSRob Herring * It doesn't make sense to enable this assumption unless
131d047cd8aSRob Herring * ASSUME_VALID_DTB is also enabled.
132d047cd8aSRob Herring */
133d047cd8aSRob Herring ASSUME_VALID_INPUT = 1 << 1,
134d047cd8aSRob Herring
135d047cd8aSRob Herring /*
136d047cd8aSRob Herring * This disables checks for device-tree version and removes all code
137d047cd8aSRob Herring * which handles older versions.
138d047cd8aSRob Herring *
139d047cd8aSRob Herring * Only enable this if you know you have a device tree with the latest
140d047cd8aSRob Herring * version.
141d047cd8aSRob Herring */
142d047cd8aSRob Herring ASSUME_LATEST = 1 << 2,
143d047cd8aSRob Herring
144d047cd8aSRob Herring /*
145d047cd8aSRob Herring * This assumes that it is OK for a failed addition to the device tree,
146d047cd8aSRob Herring * due to lack of space or some other problem, to skip any rollback
147d047cd8aSRob Herring * steps (such as dropping the property name from the string table).
148d047cd8aSRob Herring * This is safe to enable in most circumstances, even though it may
149d047cd8aSRob Herring * leave the tree in a sub-optimal state.
150d047cd8aSRob Herring */
151d047cd8aSRob Herring ASSUME_NO_ROLLBACK = 1 << 3,
152d047cd8aSRob Herring
153d047cd8aSRob Herring /*
154d047cd8aSRob Herring * This assumes that the device tree components appear in a 'convenient'
155d047cd8aSRob Herring * order, i.e. the memory reservation block first, then the structure
156d047cd8aSRob Herring * block and finally the string block.
157d047cd8aSRob Herring *
158d047cd8aSRob Herring * This order is not specified by the device-tree specification,
159d047cd8aSRob Herring * but is expected by libfdt. The device-tree compiler always created
160d047cd8aSRob Herring * device trees with this order.
161d047cd8aSRob Herring *
162d047cd8aSRob Herring * This assumption disables a check in fdt_open_into() and removes the
163d047cd8aSRob Herring * ability to fix the problem there. This is safe if you know that the
164d047cd8aSRob Herring * device tree is correctly ordered. See fdt_blocks_misordered_().
165d047cd8aSRob Herring */
166d047cd8aSRob Herring ASSUME_LIBFDT_ORDER = 1 << 4,
167d047cd8aSRob Herring
168d047cd8aSRob Herring /*
169d047cd8aSRob Herring * This assumes that libfdt itself does not have any internal bugs. It
170d047cd8aSRob Herring * drops certain checks that should never be needed unless libfdt has an
171d047cd8aSRob Herring * undiscovered bug.
172d047cd8aSRob Herring *
173d047cd8aSRob Herring * This can generally be considered safe to enable.
174d047cd8aSRob Herring */
175d047cd8aSRob Herring ASSUME_LIBFDT_FLAWLESS = 1 << 5,
176d047cd8aSRob Herring };
177d047cd8aSRob Herring
178d047cd8aSRob Herring /**
179d047cd8aSRob Herring * can_assume_() - check if a particular assumption is enabled
180d047cd8aSRob Herring *
181d047cd8aSRob Herring * @mask: Mask to check (ASSUME_...)
182d047cd8aSRob Herring * @return true if that assumption is enabled, else false
183d047cd8aSRob Herring */
can_assume_(int mask)184d047cd8aSRob Herring static inline bool can_assume_(int mask)
185d047cd8aSRob Herring {
186d047cd8aSRob Herring return FDT_ASSUME_MASK & mask;
187d047cd8aSRob Herring }
188d047cd8aSRob Herring
189d047cd8aSRob Herring /** helper macros for checking assumptions */
190d047cd8aSRob Herring #define can_assume(_assume) can_assume_(ASSUME_ ## _assume)
191d047cd8aSRob Herring
1929130ba88SRob Herring #endif /* LIBFDT_INTERNAL_H */
193