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 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 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 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 } 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 */ 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 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 */ 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