diff options
Diffstat (limited to 'scripts/dtc/libfdt/libfdt_internal.h')
| -rw-r--r-- | scripts/dtc/libfdt/libfdt_internal.h | 200 |
1 files changed, 148 insertions, 52 deletions
diff --git a/scripts/dtc/libfdt/libfdt_internal.h b/scripts/dtc/libfdt/libfdt_internal.h index 4109f890ae60..16bda1906a7b 100644 --- a/scripts/dtc/libfdt/libfdt_internal.h +++ b/scripts/dtc/libfdt/libfdt_internal.h @@ -1,66 +1,21 @@ +/* SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) */ #ifndef LIBFDT_INTERNAL_H #define LIBFDT_INTERNAL_H /* * libfdt - Flat Device Tree manipulation * Copyright (C) 2006 David Gibson, IBM Corporation. - * - * libfdt is dual licensed: you can use it either under the terms of - * the GPL, or the BSD license, at your option. - * - * a) This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License as - * published by the Free Software Foundation; either version 2 of the - * License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this library; if not, write to the Free - * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, - * MA 02110-1301 USA - * - * Alternatively, - * - * b) Redistribution and use in source and binary forms, with or - * without modification, are permitted provided that the following - * conditions are met: - * - * 1. Redistributions of source code must retain the above - * copyright notice, this list of conditions and the following - * disclaimer. - * 2. Redistributions in binary form must reproduce the above - * copyright notice, this list of conditions and the following - * disclaimer in the documentation and/or other materials - * provided with the distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND - * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, - * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF - * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE - * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR - * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT - * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; - * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN - * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR - * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, - * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include <fdt.h> #define FDT_ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1)) #define FDT_TAGALIGN(x) (FDT_ALIGN((x), FDT_TAGSIZE)) -int fdt_ro_probe_(const void *fdt); -#define FDT_RO_PROBE(fdt) \ - { \ - int err_; \ - if ((err_ = fdt_ro_probe_(fdt)) != 0) \ - return err_; \ +int32_t fdt_ro_probe_(const void *fdt); +#define FDT_RO_PROBE(fdt) \ + { \ + int32_t totalsize_; \ + if ((totalsize_ = fdt_ro_probe_(fdt)) < 0) \ + return totalsize_; \ } int fdt_check_node_offset_(const void *fdt, int offset); @@ -91,6 +46,147 @@ static inline struct fdt_reserve_entry *fdt_mem_rsv_w_(void *fdt, int n) return (void *)(uintptr_t)fdt_mem_rsv_(fdt, n); } +/* + * Internal helpers to access tructural elements of the device tree + * blob (rather than for exaple reading integers from within property + * values). We assume that we are either given a naturally aligned + * address for the platform or if we are not, we are on a platform + * where unaligned memory reads will be handled in a graceful manner. + * If not the external helpers fdtXX_ld() from libfdt.h can be used + * instead. + */ +static inline uint32_t fdt32_ld_(const fdt32_t *p) +{ + return fdt32_to_cpu(*p); +} + +static inline uint64_t fdt64_ld_(const fdt64_t *p) +{ + return fdt64_to_cpu(*p); +} + #define FDT_SW_MAGIC (~FDT_MAGIC) +/**********************************************************************/ +/* Checking controls */ +/**********************************************************************/ + +#ifndef FDT_ASSUME_MASK +#define FDT_ASSUME_MASK 0 +#endif + +/* + * Defines assumptions which can be enabled. Each of these can be enabled + * individually. For maximum safety, don't enable any assumptions! + * + * For minimal code size and no safety, use ASSUME_PERFECT at your own risk. + * You should have another method of validating the device tree, such as a + * signature or hash check before using libfdt. + * + * For situations where security is not a concern it may be safe to enable + * ASSUME_SANE. + */ +enum { + /* + * This does essentially no checks. Only the latest device-tree + * version is correctly handled. Inconsistencies or errors in the device + * tree may cause undefined behaviour or crashes. Invalid parameters + * passed to libfdt may do the same. + * + * If an error occurs when modifying the tree it may leave the tree in + * an intermediate (but valid) state. As an example, adding a property + * where there is insufficient space may result in the property name + * being added to the string table even though the property itself is + * not added to the struct section. + * + * Only use this if you have a fully validated device tree with + * the latest supported version and wish to minimise code size. + */ + ASSUME_PERFECT = 0xff, + + /* + * This assumes that the device tree is sane. i.e. header metadata + * and basic hierarchy are correct. + * + * With this assumption enabled, normal device trees produced by libfdt + * and the compiler should be handled safely. Malicious device trees and + * complete garbage may cause libfdt to behave badly or crash. Truncated + * device trees (e.g. those only partially loaded) can also cause + * problems. + * + * Note: Only checks that relate exclusively to the device tree itself + * (not the parameters passed to libfdt) are disabled by this + * assumption. This includes checking headers, tags and the like. + */ + ASSUME_VALID_DTB = 1 << 0, + + /* + * This builds on ASSUME_VALID_DTB and further assumes that libfdt + * functions are called with valid parameters, i.e. not trigger + * FDT_ERR_BADOFFSET or offsets that are out of bounds. It disables any + * extensive checking of parameters and the device tree, making various + * assumptions about correctness. + * + * It doesn't make sense to enable this assumption unless + * ASSUME_VALID_DTB is also enabled. + */ + ASSUME_VALID_INPUT = 1 << 1, + + /* + * This disables checks for device-tree version and removes all code + * which handles older versions. + * + * Only enable this if you know you have a device tree with the latest + * version. + */ + ASSUME_LATEST = 1 << 2, + + /* + * This assumes that it is OK for a failed addition to the device tree, + * due to lack of space or some other problem, to skip any rollback + * steps (such as dropping the property name from the string table). + * This is safe to enable in most circumstances, even though it may + * leave the tree in a sub-optimal state. + */ + ASSUME_NO_ROLLBACK = 1 << 3, + + /* + * This assumes that the device tree components appear in a 'convenient' + * order, i.e. the memory reservation block first, then the structure + * block and finally the string block. + * + * This order is not specified by the device-tree specification, + * but is expected by libfdt. The device-tree compiler always created + * device trees with this order. + * + * This assumption disables a check in fdt_open_into() and removes the + * ability to fix the problem there. This is safe if you know that the + * device tree is correctly ordered. See fdt_blocks_misordered_(). + */ + ASSUME_LIBFDT_ORDER = 1 << 4, + + /* + * This assumes that libfdt itself does not have any internal bugs. It + * drops certain checks that should never be needed unless libfdt has an + * undiscovered bug. + * + * This can generally be considered safe to enable. + */ + ASSUME_LIBFDT_FLAWLESS = 1 << 5, +}; + +/** + * can_assume_() - check if a particular assumption is enabled + * + * @mask: Mask to check (ASSUME_...) + * @return true if that assumption is enabled, else false + */ +static inline bool can_assume_(int mask) +{ + return FDT_ASSUME_MASK & mask; +} + +/** helper macros for checking assumptions */ +#define can_assume(_assume) can_assume_(ASSUME_ ## _assume) + #endif /* LIBFDT_INTERNAL_H */ |