55 lines
1.4 KiB
C
55 lines
1.4 KiB
C
// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
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/*
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* Relocate ourselves
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*
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* WARNING: This code is used to self-relocate, it cannot have any
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* global reference nor TOC reference. It's also called before BSS
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* is cleared.
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*
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* Copyright 2013-2015 IBM Corp.
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*/
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#include <stdbool.h>
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#include <elf.h>
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/* Called from head.S, thus no header. */
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int relocate(uint64_t offset, struct elf64_dyn *dyn, struct elf64_rela *rela);
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/* Note: This code is simplified according to the assumptions
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* that our link address is 0 and we are running at the
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* target address already.
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*/
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int relocate(uint64_t offset, struct elf64_dyn *dyn, struct elf64_rela *rela)
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{
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uint64_t dt_rela = 0;
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uint64_t dt_relacount = 0;
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unsigned int i;
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/* Look for relocation table */
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for (; dyn->d_tag != DT_NULL; dyn++) {
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if (dyn->d_tag == DT_RELA)
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dt_rela = dyn->d_val;
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else if (dyn->d_tag == DT_RELACOUNT)
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dt_relacount = dyn->d_val;
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}
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/* If we miss either rela or relacount, bail */
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if (!dt_rela || !dt_relacount)
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return -1;
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/* Check if the offset is consistent */
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if ((offset + dt_rela) != (uint64_t)rela)
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return -2;
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/* Perform relocations */
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for (i = 0; i < dt_relacount; i++, rela++) {
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uint64_t *t;
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if (ELF64_R_TYPE(rela->r_info) != R_PPC64_RELATIVE)
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return -3;
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t = (uint64_t *)(rela->r_offset + offset);
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*t = rela->r_addend + offset;
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}
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return 0;
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}
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