455 lines
12 KiB
C
455 lines
12 KiB
C
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/* $NetBSD: mips_reloc.c,v 1.60 2010/09/24 15:20:52 matt Exp $ */
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/*
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* Copyright 1997 Michael L. Hitch <mhitch@montana.edu>
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* Portions copyright 2002 Charles M. Hannum <root@ihack.net>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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__RCSID("$NetBSD: mips_reloc.c,v 1.60 2010/09/24 15:20:52 matt Exp $");
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#endif /* not lint */
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#include <sys/types.h>
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#include <sys/endian.h>
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#include <stdlib.h>
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#include <string.h>
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#include "debug.h"
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#include "rtld.h"
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#ifdef __mips_o32
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#define SUPPORT_OLD_BROKEN_LD
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#endif
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void _rtld_bind_start(void);
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void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
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caddr_t _rtld_bind(Elf_Word, Elf_Addr, Elf_Addr, Elf_Addr);
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/*
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* It is possible for the compiler to emit relocations for unaligned data.
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* We handle this situation with these inlines.
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*/
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#if ELFSIZE == 64
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/*
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* ELF64 MIPS encodes the relocs uniquely. The first 32-bits of info contain
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* the symbol index. The top 32-bits contain three relocation types encoded
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* in big-endian integer with first relocation in LSB. This means for little
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* endian we have to byte swap that interger (r_type).
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*/
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#define Elf_Sxword Elf64_Sxword
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#define ELF_R_NXTTYPE_64_P(r_type) ((((r_type) >> 8) & 0xff) == R_TYPE(64))
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#if BYTE_ORDER == LITTLE_ENDIAN
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#undef ELF_R_SYM
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#undef ELF_R_TYPE
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#define ELF_R_SYM(r_info) ((r_info) & 0xffffffff)
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#define ELF_R_TYPE(r_info) bswap32((r_info) >> 32)
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#endif
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#else
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#define ELF_R_NXTTYPE_64_P(r_type) (0)
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#define Elf_Sxword Elf32_Sword
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#endif
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#define GOT1_MASK (~(Elf_Addr)0 >> 1)
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static inline Elf_Sxword
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load_ptr(void *where, size_t len)
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{
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Elf_Sxword val;
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if (__predict_true(((uintptr_t)where & (len - 1)) == 0)) {
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#if ELFSIZE == 64
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if (len == sizeof(Elf_Sxword))
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return *(Elf_Sxword *)where;
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#endif
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return *(Elf_Sword *)where;
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}
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val = 0;
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#if BYTE_ORDER == LITTLE_ENDIAN
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(void)memcpy(&val, where, len);
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#endif
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#if BYTE_ORDER == BIG_ENDIAN
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(void)memcpy((uint8_t *)((&val)+1) - len, where, len);
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#endif
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return (len == sizeof(Elf_Sxword)) ? val : (Elf_Sword)val;
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}
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static inline void
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store_ptr(void *where, Elf_Sxword val, size_t len)
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{
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if (__predict_true(((uintptr_t)where & (len - 1)) == 0)) {
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#if ELFSIZE == 64
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if (len == sizeof(Elf_Sxword)) {
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*(Elf_Sxword *)where = val;
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return;
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}
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#endif
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*(Elf_Sword *)where = val;
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return;
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}
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#if BYTE_ORDER == LITTLE_ENDIAN
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(void)memcpy(where, &val, len);
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#endif
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#if BYTE_ORDER == BIG_ENDIAN
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(void)memcpy(where, (const uint8_t *)((&val)+1) - len, len);
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#endif
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}
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void
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_rtld_setup_pltgot(const Obj_Entry *obj)
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{
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obj->pltgot[0] = (Elf_Addr) &_rtld_bind_start;
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/* XXX only if obj->pltgot[1] & 0x80000000 ?? */
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obj->pltgot[1] |= (Elf_Addr) obj;
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}
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void
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_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
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{
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const Elf_Rel *rel = 0, *rellim;
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Elf_Addr relsz = 0;
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void *where;
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const Elf_Sym *symtab = NULL, *sym;
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Elf_Addr *got = NULL;
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Elf_Word local_gotno = 0, symtabno = 0, gotsym = 0;
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size_t i;
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for (; dynp->d_tag != DT_NULL; dynp++) {
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switch (dynp->d_tag) {
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case DT_REL:
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rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr);
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break;
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case DT_RELSZ:
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relsz = dynp->d_un.d_val;
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break;
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case DT_SYMTAB:
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symtab = (const Elf_Sym *)(relocbase + dynp->d_un.d_ptr);
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break;
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case DT_PLTGOT:
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got = (Elf_Addr *)(relocbase + dynp->d_un.d_ptr);
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break;
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case DT_MIPS_LOCAL_GOTNO:
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local_gotno = dynp->d_un.d_val;
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break;
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case DT_MIPS_SYMTABNO:
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symtabno = dynp->d_un.d_val;
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break;
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case DT_MIPS_GOTSYM:
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gotsym = dynp->d_un.d_val;
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break;
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}
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}
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i = (got[1] & 0x80000000) ? 2 : 1;
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/* Relocate the local GOT entries */
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got += i;
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for (; i < local_gotno; i++)
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*got++ += relocbase;
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sym = symtab + gotsym;
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/* Now do the global GOT entries */
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for (i = gotsym; i < symtabno; i++) {
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*got = sym->st_value + relocbase;
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++sym;
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++got;
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}
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rellim = (const Elf_Rel *)((uintptr_t)rel + relsz);
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for (; rel < rellim; rel++) {
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Elf_Word r_symndx, r_type;
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where = (void *)(relocbase + rel->r_offset);
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r_symndx = ELF_R_SYM(rel->r_info);
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r_type = ELF_R_TYPE(rel->r_info);
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switch (r_type & 0xff) {
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case R_TYPE(REL32): {
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const size_t rlen =
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ELF_R_NXTTYPE_64_P(r_type)
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? sizeof(Elf_Sxword)
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: sizeof(Elf_Sword);
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Elf_Sxword old = load_ptr(where, rlen);
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Elf_Sxword val = old;
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#if ELFSIZE == 64
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assert(r_type == R_TYPE(REL32)
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|| r_type == (R_TYPE(REL32)|(R_TYPE(64) << 8)));
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#endif
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assert(r_symndx < gotsym);
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sym = symtab + r_symndx;
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assert(ELF_ST_BIND(sym->st_info) == STB_LOCAL);
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val += relocbase;
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store_ptr(where, val, sizeof(Elf_Sword));
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rdbg(("REL32/L(%p) %p -> %p in <self>",
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where, (void *)old, (void *)val));
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store_ptr(where, val, rlen);
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break;
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}
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case R_TYPE(GPREL32):
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case R_TYPE(NONE):
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break;
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default:
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abort();
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}
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}
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}
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int
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_rtld_relocate_nonplt_objects(Obj_Entry *obj)
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{
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const Elf_Rel *rel;
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Elf_Addr *got = obj->pltgot;
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const Elf_Sym *sym, *def;
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const Obj_Entry *defobj;
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Elf_Word i;
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#ifdef SUPPORT_OLD_BROKEN_LD
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int broken;
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#endif
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#ifdef SUPPORT_OLD_BROKEN_LD
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broken = 0;
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sym = obj->symtab;
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for (i = 1; i < 12; i++)
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if (sym[i].st_info == ELF_ST_INFO(STB_LOCAL, STT_NOTYPE))
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broken = 1;
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dbg(("%s: broken=%d", obj->path, broken));
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#endif
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i = (got[1] & 0x80000000) ? 2 : 1;
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/* Relocate the local GOT entries */
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got += i;
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for (; i < obj->local_gotno; i++)
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*got++ += (Elf_Addr)obj->relocbase;
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sym = obj->symtab + obj->gotsym;
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/* Now do the global GOT entries */
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for (i = obj->gotsym; i < obj->symtabno; i++) {
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rdbg((" doing got %d sym %p (%s, %lx)", i - obj->gotsym, sym,
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sym->st_name + obj->strtab, (u_long) *got));
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#ifdef SUPPORT_OLD_BROKEN_LD
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if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
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broken && sym->st_shndx == SHN_UNDEF) {
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/*
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* XXX DANGER WILL ROBINSON!
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* You might think this is stupid, as it intentionally
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* defeats lazy binding -- and you'd be right.
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* Unfortunately, for lazy binding to work right, we
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* need to a way to force the GOT slots used for
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* function pointers to be resolved immediately. This
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* is supposed to be done automatically by the linker,
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* by not outputting a PLT slot and setting st_value
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* to 0 if there are non-PLT references, but older
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* versions of GNU ld do not do this.
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*/
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def = _rtld_find_symdef(i, obj, &defobj, false);
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if (def == NULL)
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return -1;
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*got = def->st_value + (Elf_Addr)defobj->relocbase;
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} else
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#endif
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if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
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sym->st_value != 0 && sym->st_shndx == SHN_UNDEF) {
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/*
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* If there are non-PLT references to the function,
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* st_value should be 0, forcing us to resolve the
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* address immediately.
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*
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* XXX DANGER WILL ROBINSON!
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* The linker is not outputting PLT slots for calls to
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* functions that are defined in the same shared
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* library. This is a bug, because it can screw up
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* link ordering rules if the symbol is defined in
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* more than one module. For now, if there is a
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* definition, we fail the test above and force a full
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* symbol lookup. This means that all intra-module
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* calls are bound immediately. - mycroft, 2003/09/24
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*/
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*got = sym->st_value + (Elf_Addr)obj->relocbase;
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} else if (sym->st_info == ELF_ST_INFO(STB_GLOBAL, STT_SECTION)) {
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/* Symbols with index SHN_ABS are not relocated. */
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if (sym->st_shndx != SHN_ABS)
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*got = sym->st_value +
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(Elf_Addr)obj->relocbase;
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} else {
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def = _rtld_find_symdef(i, obj, &defobj, false);
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if (def == NULL)
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return -1;
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*got = def->st_value + (Elf_Addr)defobj->relocbase;
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}
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rdbg((" --> now %lx", (u_long) *got));
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++sym;
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++got;
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}
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got = obj->pltgot;
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for (rel = obj->rel; rel < obj->rellim; rel++) {
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Elf_Word r_symndx, r_type;
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void *where;
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where = obj->relocbase + rel->r_offset;
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r_symndx = ELF_R_SYM(rel->r_info);
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r_type = ELF_R_TYPE(rel->r_info);
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switch (r_type & 0xff) {
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case R_TYPE(NONE):
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break;
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case R_TYPE(REL32): {
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/* 32-bit PC-relative reference */
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const size_t rlen =
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ELF_R_NXTTYPE_64_P(r_type)
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? sizeof(Elf_Sxword)
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: sizeof(Elf_Sword);
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Elf_Sxword old = load_ptr(where, rlen);
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Elf_Sxword val = old;
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def = obj->symtab + r_symndx;
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if (r_symndx >= obj->gotsym) {
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val += got[obj->local_gotno + r_symndx - obj->gotsym];
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rdbg(("REL32/G(%p) %p --> %p (%s) in %s",
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where, (void *)old, (void *)val,
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obj->strtab + def->st_name,
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obj->path));
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} else {
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/*
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* XXX: ABI DIFFERENCE!
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*
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* Old NetBSD binutils would generate shared
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* libs with section-relative relocations being
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* already adjusted for the start address of
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|
* the section.
|
||
|
|
*
|
||
|
|
* New binutils, OTOH, generate shared libs
|
||
|
|
* with the same relocations being based at
|
||
|
|
* zero, so we need to add in the start address
|
||
|
|
* of the section.
|
||
|
|
*
|
||
|
|
* --rkb, Oct 6, 2001
|
||
|
|
*/
|
||
|
|
|
||
|
|
if (def->st_info ==
|
||
|
|
ELF_ST_INFO(STB_LOCAL, STT_SECTION)
|
||
|
|
#ifdef SUPPORT_OLD_BROKEN_LD
|
||
|
|
&& !broken
|
||
|
|
#endif
|
||
|
|
)
|
||
|
|
val += (Elf_Addr)def->st_value;
|
||
|
|
|
||
|
|
val += (Elf_Addr)obj->relocbase;
|
||
|
|
|
||
|
|
rdbg(("REL32/L(%p) %p -> %p (%s) in %s",
|
||
|
|
where, (void *)old, (void *)val,
|
||
|
|
obj->strtab + def->st_name, obj->path));
|
||
|
|
}
|
||
|
|
store_ptr(where, val, rlen);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
default:
|
||
|
|
rdbg(("sym = %lu, type = %lu, offset = %p, "
|
||
|
|
"contents = %p, symbol = %s",
|
||
|
|
(u_long)r_symndx, (u_long)ELF_R_TYPE(rel->r_info),
|
||
|
|
(void *)rel->r_offset,
|
||
|
|
(void *)load_ptr(where, sizeof(Elf_Sword)),
|
||
|
|
obj->strtab + obj->symtab[r_symndx].st_name));
|
||
|
|
_rtld_error("%s: Unsupported relocation type %ld "
|
||
|
|
"in non-PLT relocations",
|
||
|
|
obj->path, (u_long) ELF_R_TYPE(rel->r_info));
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
_rtld_relocate_plt_lazy(const Obj_Entry *obj)
|
||
|
|
{
|
||
|
|
/* PLT fixups were done above in the GOT relocation. */
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline int
|
||
|
|
_rtld_relocate_plt_object(const Obj_Entry *obj, Elf_Word sym, Elf_Addr *tp)
|
||
|
|
{
|
||
|
|
Elf_Addr *got = obj->pltgot;
|
||
|
|
const Elf_Sym *def;
|
||
|
|
const Obj_Entry *defobj;
|
||
|
|
Elf_Addr new_value;
|
||
|
|
|
||
|
|
def = _rtld_find_plt_symdef(sym, obj, &defobj, tp != NULL);
|
||
|
|
if (__predict_false(def == NULL))
|
||
|
|
return -1;
|
||
|
|
if (__predict_false(def == &_rtld_sym_zero))
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
new_value = (Elf_Addr)(defobj->relocbase + def->st_value);
|
||
|
|
rdbg(("bind now/fixup in %s --> new=%p",
|
||
|
|
defobj->strtab + def->st_name, (void *)new_value));
|
||
|
|
got[obj->local_gotno + sym - obj->gotsym] = new_value;
|
||
|
|
|
||
|
|
if (tp)
|
||
|
|
*tp = new_value;
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
caddr_t
|
||
|
|
_rtld_bind(Elf_Word a0, Elf_Addr a1, Elf_Addr a2, Elf_Addr a3)
|
||
|
|
{
|
||
|
|
Elf_Addr *got = (Elf_Addr *)(a2 - 0x7ff0);
|
||
|
|
const Obj_Entry *obj = (Obj_Entry *)(got[1] & GOT1_MASK);
|
||
|
|
Elf_Addr new_value = 0; /* XXX gcc */
|
||
|
|
int err;
|
||
|
|
|
||
|
|
err = _rtld_relocate_plt_object(obj, a0, &new_value);
|
||
|
|
if (err)
|
||
|
|
_rtld_die();
|
||
|
|
|
||
|
|
return (caddr_t)new_value;
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
_rtld_relocate_plt_objects(const Obj_Entry *obj)
|
||
|
|
{
|
||
|
|
const Elf_Sym *sym = obj->symtab + obj->gotsym;
|
||
|
|
Elf_Word i;
|
||
|
|
|
||
|
|
for (i = obj->gotsym; i < obj->symtabno; i++, sym++) {
|
||
|
|
if (ELF_ST_TYPE(sym->st_info) == STT_FUNC)
|
||
|
|
if (_rtld_relocate_plt_object(obj, i, NULL) < 0)
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|