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https://github.com/AsahiLinux/u-boot
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367ecbf2d3
Binman lets us declare symbols in SPL/TPL that refer to other entries in the same binman image as them. These symbols are filled in with the correct values while binman assembles the images, but this is done in-memory only. Symbols marked as optional can be filled with BINMAN_SYM_MISSING as an error value if their referred entry is missing. However, the unmodified SPL/TPL binaries are still available on disk, and can be used by people. For these files, nothing ensures that the symbols are set to this error value, and they will be considered valid when they are not. Empirically, all symbols show up as zero in a sandbox_vpl build when we run e.g. tpl/u-boot-tpl directly. On the other hand, zero is a perfectly fine value for a binman-written symbol, so we cannot say the symbols have wrong values based on that. Declare a magic symbol that binman always fills in with a fixed value. Check this value as an indicator that symbols were filled in correctly. Return the error value for all symbols when this magic symbol has the wrong value. For binman tests, we need to make room for the new symbol in the mocked SPL/TPL data by extending them by four bytes. This messes up some test image layouts. Fix the affected values, and check the magic symbol wherever it makes sense. Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
133 lines
4.3 KiB
C
133 lines
4.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Symbol access for symbols set up by binman as part of the build.
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*
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* This allows C code to access the position of a particular part of the image
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* assembled by binman.
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*
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* Copyright (c) 2017 Google, Inc
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*/
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#ifndef __BINMAN_SYM_H
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#define __BINMAN_SYM_H
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/* BSYM in little endian, keep in sync with tools/binman/elf.py */
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#define BINMAN_SYM_MAGIC_VALUE (0x4d595342UL)
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#define BINMAN_SYM_MISSING (-1UL)
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#if CONFIG_IS_ENABLED(BINMAN_SYMBOLS)
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/**
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* binman_symname() - Internal function to get a binman symbol name
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*
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* @entry_name: Name of the entry to look for (e.g. 'u_boot_spl')
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* @_prop_name: Property value to get from that entry (e.g. 'pos')
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* @returns name of the symbol for that entry and property
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*/
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#define binman_symname(_entry_name, _prop_name) \
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_binman_ ## _entry_name ## _prop_ ## _prop_name
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/**
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* binman_sym_declare() - Declare a symbol that will be used at run-time
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*
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* @_type: Type f the symbol (e.g. unsigned long)
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* @entry_name: Name of the entry to look for (e.g. 'u_boot_spl')
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* @_prop_name: Property value to get from that entry (e.g. 'pos')
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*/
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#define binman_sym_declare(_type, _entry_name, _prop_name) \
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_type binman_symname(_entry_name, _prop_name) \
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__attribute__((aligned(4), unused, section(".binman_sym")))
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/**
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* binman_sym_extern() - Declare a extern symbol that will be used at run-time
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*
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* @_type: Type f the symbol (e.g. unsigned long)
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* @entry_name: Name of the entry to look for (e.g. 'u_boot_spl')
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* @_prop_name: Property value to get from that entry (e.g. 'pos')
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*/
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#define binman_sym_extern(_type, _entry_name, _prop_name) \
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extern _type binman_symname(_entry_name, _prop_name) \
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__attribute__((aligned(4), unused, section(".binman_sym")))
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/**
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* binman_sym_declare_optional() - Declare an optional symbol
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*
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* If this symbol cannot be provided by binman, an error will not be generated.
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* Instead the image will be assigned the value BINMAN_SYM_MISSING.
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*
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* @_type: Type f the symbol (e.g. unsigned long)
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* @entry_name: Name of the entry to look for (e.g. 'u_boot_spl')
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* @_prop_name: Property value to get from that entry (e.g. 'pos')
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*/
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#define binman_sym_declare_optional(_type, _entry_name, _prop_name) \
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_type binman_symname(_entry_name, _prop_name) \
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__attribute__((aligned(4), weak, unused, \
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section(".binman_sym")))
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/**
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* _binman_sym_magic - Internal magic symbol for validity checks
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*
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* When building images, binman fills in this symbol with the magic
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* value #defined above. This is used to check at runtime if the
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* symbol values were filled in and are OK to use.
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*/
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extern ulong _binman_sym_magic;
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/**
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* DECLARE_BINMAN_MAGIC_SYM - Declare the internal magic symbol
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*
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* This macro declares the _binman_sym_magic symbol so that it exists.
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* Declaring it here would cause errors during linking due to multiple
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* definitions of the symbol.
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*/
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#define DECLARE_BINMAN_MAGIC_SYM \
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ulong _binman_sym_magic \
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__attribute__((aligned(4), section(".binman_sym")))
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/**
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* BINMAN_SYMS_OK - Check if the symbol values are valid
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*
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* This macro checks if the magic symbol's value is filled properly,
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* which indicates that other symbols are OK to use as well.
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*
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* Return: 1 if binman symbol values are usable, 0 if not
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*/
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#define BINMAN_SYMS_OK \
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(*(ulong *)&_binman_sym_magic == BINMAN_SYM_MAGIC_VALUE)
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/**
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* binman_sym() - Access a previously declared symbol
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*
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* This is used to get the value of a symbol. E.g.:
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*
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* ulong address = binman_sym(ulong, u_boot_spl, pos);
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*
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* @_type: Type f the symbol (e.g. unsigned long)
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* @entry_name: Name of the entry to look for (e.g. 'u_boot_spl')
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* @_prop_name: Property value to get from that entry (e.g. 'pos')
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*
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* Return: value of that property (filled in by binman), or
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* BINMAN_SYM_MISSING if the value is unavailable
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*/
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#define binman_sym(_type, _entry_name, _prop_name) \
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(BINMAN_SYMS_OK ? \
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(*(_type *)&binman_symname(_entry_name, _prop_name)) : \
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BINMAN_SYM_MISSING)
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#else /* !CONFIG_IS_ENABLED(BINMAN_SYMBOLS) */
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#define binman_sym_declare(_type, _entry_name, _prop_name)
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#define binman_sym_declare_optional(_type, _entry_name, _prop_name)
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#define binman_sym_extern(_type, _entry_name, _prop_name)
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#define DECLARE_BINMAN_MAGIC_SYM
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#define BINMAN_SYMS_OK (0)
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#define binman_sym(_type, _entry_name, _prop_name) BINMAN_SYM_MISSING
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#endif /* CONFIG_IS_ENABLED(BINMAN_SYMBOLS) */
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#endif
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