193 lines
6.3 KiB
C
193 lines
6.3 KiB
C
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/* SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) */
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#ifndef LIBFDT_INTERNAL_H
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#define LIBFDT_INTERNAL_H
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/*
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* libfdt - Flat Device Tree manipulation
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* Copyright (C) 2006 David Gibson, IBM Corporation.
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*/
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#include <fdt.h>
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#define FDT_ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1))
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#define FDT_TAGALIGN(x) (FDT_ALIGN((x), FDT_TAGSIZE))
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int32_t fdt_ro_probe_(const void *fdt);
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#define FDT_RO_PROBE(fdt) \
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{ \
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int32_t totalsize_; \
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if ((totalsize_ = fdt_ro_probe_(fdt)) < 0) \
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return totalsize_; \
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}
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int fdt_check_node_offset_(const void *fdt, int offset);
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int fdt_check_prop_offset_(const void *fdt, int offset);
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const char *fdt_find_string_(const char *strtab, int tabsize, const char *s);
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int fdt_node_end_offset_(void *fdt, int nodeoffset);
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static inline const void *fdt_offset_ptr_(const void *fdt, int offset)
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{
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return (const char *)fdt + fdt_off_dt_struct(fdt) + offset;
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}
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static inline void *fdt_offset_ptr_w_(void *fdt, int offset)
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{
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return (void *)(uintptr_t)fdt_offset_ptr_(fdt, offset);
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}
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static inline const struct fdt_reserve_entry *fdt_mem_rsv_(const void *fdt, int n)
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{
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const struct fdt_reserve_entry *rsv_table =
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(const struct fdt_reserve_entry *)
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((const char *)fdt + fdt_off_mem_rsvmap(fdt));
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return rsv_table + n;
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}
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static inline struct fdt_reserve_entry *fdt_mem_rsv_w_(void *fdt, int n)
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{
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return (void *)(uintptr_t)fdt_mem_rsv_(fdt, n);
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}
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/*
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* Internal helpers to access tructural elements of the device tree
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* blob (rather than for exaple reading integers from within property
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* values). We assume that we are either given a naturally aligned
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* address for the platform or if we are not, we are on a platform
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* where unaligned memory reads will be handled in a graceful manner.
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* If not the external helpers fdtXX_ld() from libfdt.h can be used
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* instead.
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*/
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static inline uint32_t fdt32_ld_(const fdt32_t *p)
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{
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return fdt32_to_cpu(*p);
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}
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static inline uint64_t fdt64_ld_(const fdt64_t *p)
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{
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return fdt64_to_cpu(*p);
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}
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#define FDT_SW_MAGIC (~FDT_MAGIC)
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/**********************************************************************/
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/* Checking controls */
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/**********************************************************************/
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#ifndef FDT_ASSUME_MASK
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#define FDT_ASSUME_MASK 0
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#endif
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/*
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* Defines assumptions which can be enabled. Each of these can be enabled
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* individually. For maximum safety, don't enable any assumptions!
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*
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* For minimal code size and no safety, use ASSUME_PERFECT at your own risk.
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* You should have another method of validating the device tree, such as a
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* signature or hash check before using libfdt.
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*
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* For situations where security is not a concern it may be safe to enable
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* ASSUME_SANE.
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*/
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enum {
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/*
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* This does essentially no checks. Only the latest device-tree
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* version is correctly handled. Inconsistencies or errors in the device
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* tree may cause undefined behaviour or crashes. Invalid parameters
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* passed to libfdt may do the same.
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*
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* If an error occurs when modifying the tree it may leave the tree in
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* an intermediate (but valid) state. As an example, adding a property
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* where there is insufficient space may result in the property name
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* being added to the string table even though the property itself is
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* not added to the struct section.
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*
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* Only use this if you have a fully validated device tree with
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* the latest supported version and wish to minimise code size.
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*/
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ASSUME_PERFECT = 0xff,
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/*
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* This assumes that the device tree is sane. i.e. header metadata
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* and basic hierarchy are correct.
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*
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* With this assumption enabled, normal device trees produced by libfdt
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* and the compiler should be handled safely. Malicious device trees and
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* complete garbage may cause libfdt to behave badly or crash. Truncated
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* device trees (e.g. those only partially loaded) can also cause
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* problems.
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*
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* Note: Only checks that relate exclusively to the device tree itself
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* (not the parameters passed to libfdt) are disabled by this
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* assumption. This includes checking headers, tags and the like.
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*/
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ASSUME_VALID_DTB = 1 << 0,
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/*
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* This builds on ASSUME_VALID_DTB and further assumes that libfdt
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* functions are called with valid parameters, i.e. not trigger
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* FDT_ERR_BADOFFSET or offsets that are out of bounds. It disables any
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* extensive checking of parameters and the device tree, making various
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* assumptions about correctness.
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*
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* It doesn't make sense to enable this assumption unless
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* ASSUME_VALID_DTB is also enabled.
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*/
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ASSUME_VALID_INPUT = 1 << 1,
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/*
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* This disables checks for device-tree version and removes all code
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* which handles older versions.
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*
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* Only enable this if you know you have a device tree with the latest
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* version.
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*/
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ASSUME_LATEST = 1 << 2,
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/*
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* This assumes that it is OK for a failed addition to the device tree,
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* due to lack of space or some other problem, to skip any rollback
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* steps (such as dropping the property name from the string table).
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* This is safe to enable in most circumstances, even though it may
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* leave the tree in a sub-optimal state.
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*/
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ASSUME_NO_ROLLBACK = 1 << 3,
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/*
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* This assumes that the device tree components appear in a 'convenient'
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* order, i.e. the memory reservation block first, then the structure
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* block and finally the string block.
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*
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* This order is not specified by the device-tree specification,
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* but is expected by libfdt. The device-tree compiler always created
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* device trees with this order.
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*
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* This assumption disables a check in fdt_open_into() and removes the
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* ability to fix the problem there. This is safe if you know that the
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* device tree is correctly ordered. See fdt_blocks_misordered_().
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*/
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ASSUME_LIBFDT_ORDER = 1 << 4,
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/*
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* This assumes that libfdt itself does not have any internal bugs. It
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* drops certain checks that should never be needed unless libfdt has an
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* undiscovered bug.
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*
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* This can generally be considered safe to enable.
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*/
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ASSUME_LIBFDT_FLAWLESS = 1 << 5,
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};
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/**
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* can_assume_() - check if a particular assumption is enabled
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*
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* @mask: Mask to check (ASSUME_...)
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* @return true if that assumption is enabled, else false
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*/
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static inline bool can_assume_(int mask)
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{
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return FDT_ASSUME_MASK & mask;
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}
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/** helper macros for checking assumptions */
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#define can_assume(_assume) can_assume_(ASSUME_ ## _assume)
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#endif /* LIBFDT_INTERNAL_H */
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