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Parse MIPS relocations to unbreak kldxref on MIPS.

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Parse the R_MIPS_32 and R_MIPS_64 relocations.  Both Elf_Rel and
Elf_Rela relocations are handled since O32 MIPS uses Elf_Rel while N64
uses Elf_Rela.  Note that R_MIPS_32 is only handled for 32-bit mips
and R_MIPS_64 for 64-bit.  N32 is untested.

Reviewed by:	imp
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D19870
This commit is contained in:
John Baldwin 2019-04-24 23:35:10 +00:00
parent 6b0451d603
commit c1bba4445c
1 changed files with 99 additions and 0 deletions
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99
usr.sbin/kldxref/ef_mips.c Normal file
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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2019 John Baldwin <jhb@FreeBSD.org>
*
* This software was developed by SRI International and the University of
* Cambridge Computer Laboratory (Department of Computer Science and
* Technology) under DARPA contract HR0011-18-C-0016 ("ECATS"), as part of the
* DARPA SSITH research programme.
*
* 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 AUTHOR 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 AUTHOR 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.
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <machine/elf.h>
#include <err.h>
#include <errno.h>
#include "ef.h"
/*
* Apply relocations to the values we got from the file. `relbase' is the
* target relocation address of the section, and `dataoff' is the target
* relocation address of the data in `dest'.
*/
int
ef_reloc(struct elf_file *ef, const void *reldata, int reltype, Elf_Off relbase,
Elf_Off dataoff, size_t len, void *dest)
{
Elf_Addr *where, val;
const Elf_Rel *rel;
const Elf_Rela *rela;
Elf_Addr addend, addr;
Elf_Size rtype, symidx;
switch (reltype) {
case EF_RELOC_REL:
rel = (const Elf_Rel *)reldata;
where = (Elf_Addr *)((char *)dest + relbase + rel->r_offset -
dataoff);
addend = 0;
rtype = ELF_R_TYPE(rel->r_info);
symidx = ELF_R_SYM(rel->r_info);
break;
case EF_RELOC_RELA:
rela = (const Elf_Rela *)reldata;
where = (Elf_Addr *)((char *)dest + relbase + rela->r_offset -
dataoff);
addend = rela->r_addend;
rtype = ELF_R_TYPE(rela->r_info);
symidx = ELF_R_SYM(rela->r_info);
break;
default:
return (EINVAL);
}
if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len)
return (0);
if (reltype == EF_RELOC_REL)
addend = *where;
switch (rtype) {
#ifdef __LP64__
case R_MIPS_64: /* S + A */
#else
case R_MIPS_32: /* S + A */
#endif
addr = EF_SYMADDR(ef, symidx);
val = addr + addend;
*where = val;
break;
default:
warnx("unhandled relocation type %d", (int)rtype);
}
return (0);
}