/* $NetBSD: mips_reloc.c,v 1.58 2010/01/14 11:57:06 skrll Exp $ */ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright 1997 Michael L. Hitch * Portions copyright 2002 Charles M. Hannum * All rights reserved. * * 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. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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. */ #include #include #include #include #include #include #include #include #include #include "debug.h" #include "rtld.h" #ifdef __mips_n64 #define GOT1_MASK 0x8000000000000000UL #else #define GOT1_MASK 0x80000000UL #endif /* * Determine if the second GOT entry is reserved for rtld or if it is * the first "real" GOT entry. * * This must be a macro rather than a function so that * _rtld_relocate_nonplt_self doesn't trigger a GOT invocation trying * to use it before the local GOT entries in rtld are adjusted. */ #ifdef __mips_n64 /* Old binutils uses the 32-bit GOT1 mask value for N64. */ #define GOT1_RESERVED_FOR_RTLD(got) \ (((got)[1] == 0x80000000) || (got)[1] & GOT1_MASK) #else #define GOT1_RESERVED_FOR_RTLD(got) ((got)[1] & GOT1_MASK) #endif #ifdef __mips_n64 /* * ELF64 MIPS encodes the relocs uniquely. The first 32-bits of info contain * the symbol index. The top 32-bits contain three relocation types encoded * in big-endian integer with first relocation in LSB. This means for little * endian we have to byte swap that integer (r_type). */ #define Elf_Sxword Elf64_Sxword #define ELF_R_NXTTYPE_64_P(r_type) ((((r_type) >> 8) & 0xff) == R_TYPE(64)) #if BYTE_ORDER == LITTLE_ENDIAN #undef ELF_R_SYM #undef ELF_R_TYPE #define ELF_R_SYM(r_info) ((r_info) & 0xffffffff) #define ELF_R_TYPE(r_info) bswap32((r_info) >> 32) #endif #else #define ELF_R_NXTTYPE_64_P(r_type) (0) #define Elf_Sxword Elf32_Sword #endif void _rtld_pltbind_start(void); void init_pltgot(Obj_Entry *obj) { if (obj->pltgot != NULL) { obj->pltgot[0] = (Elf_Addr) &_rtld_bind_start; if (GOT1_RESERVED_FOR_RTLD(obj->pltgot)) obj->pltgot[1] = (Elf_Addr) obj | GOT1_MASK; } if (obj->mips_pltgot != NULL) { obj->mips_pltgot[0] = (Elf_Addr) &_rtld_pltbind_start; obj->mips_pltgot[1] = (Elf_Addr) obj; } } int do_copy_relocations(Obj_Entry *dstobj) { const Obj_Entry *srcobj, *defobj; const Elf_Rel *rellim; const Elf_Rel *rel; const Elf_Sym *srcsym; const Elf_Sym *dstsym; const void *srcaddr; const char *name; void *dstaddr; SymLook req; size_t size; int res; /* * COPY relocs are invalid outside of the main program */ assert(dstobj->mainprog); rellim = (const Elf_Rel *)((const char *)dstobj->rel + dstobj->relsize); for (rel = dstobj->rel; rel < rellim; rel++) { if (ELF_R_TYPE(rel->r_info) != R_MIPS_COPY) continue; dstaddr = (void *)(dstobj->relocbase + rel->r_offset); dstsym = dstobj->symtab + ELF_R_SYM(rel->r_info); name = dstobj->strtab + dstsym->st_name; size = dstsym->st_size; symlook_init(&req, name); req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rel->r_info)); req.flags = SYMLOOK_EARLY; for (srcobj = globallist_next(dstobj); srcobj != NULL; srcobj = globallist_next(srcobj)) { res = symlook_obj(&req, srcobj); if (res == 0) { srcsym = req.sym_out; defobj = req.defobj_out; break; } } if (srcobj == NULL) { _rtld_error( "Undefined symbol \"%s\" referenced from COPY relocation in %s", name, dstobj->path); return (-1); } srcaddr = (const void *)(defobj->relocbase + srcsym->st_value); memcpy(dstaddr, srcaddr, size); } return (0); } void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); /* * It is possible for the compiler to emit relocations for unaligned data. * We handle this situation with these inlines. */ static __inline Elf_Sxword load_ptr(void *where, size_t len) { Elf_Sxword val; if (__predict_true(((uintptr_t)where & (len - 1)) == 0)) { #ifdef __mips_n64 if (len == sizeof(Elf_Sxword)) return *(Elf_Sxword *)where; #endif return *(Elf_Sword *)where; } val = 0; #if BYTE_ORDER == LITTLE_ENDIAN (void)memcpy(&val, where, len); #endif #if BYTE_ORDER == BIG_ENDIAN (void)memcpy((uint8_t *)((&val)+1) - len, where, len); #endif return (len == sizeof(Elf_Sxword)) ? val : (Elf_Sword)val; } static __inline void store_ptr(void *where, Elf_Sxword val, size_t len) { if (__predict_true(((uintptr_t)where & (len - 1)) == 0)) { #ifdef __mips_n64 if (len == sizeof(Elf_Sxword)) { *(Elf_Sxword *)where = val; return; } #endif *(Elf_Sword *)where = val; return; } #if BYTE_ORDER == LITTLE_ENDIAN (void)memcpy(where, &val, len); #endif #if BYTE_ORDER == BIG_ENDIAN (void)memcpy(where, (const uint8_t *)((&val)+1) - len, len); #endif } void _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) { const Elf_Rel *rel = NULL, *rellim; Elf_Addr relsz = 0; const Elf_Sym *symtab = NULL, *sym; Elf_Addr *where; Elf_Addr *got = NULL; Elf_Word local_gotno = 0, symtabno = 0, gotsym = 0; size_t i; for (; dynp->d_tag != DT_NULL; dynp++) { switch (dynp->d_tag) { case DT_REL: rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr); break; case DT_RELSZ: relsz = dynp->d_un.d_val; break; case DT_SYMTAB: symtab = (const Elf_Sym *)(relocbase + dynp->d_un.d_ptr); break; case DT_PLTGOT: got = (Elf_Addr *)(relocbase + dynp->d_un.d_ptr); break; case DT_MIPS_LOCAL_GOTNO: local_gotno = dynp->d_un.d_val; break; case DT_MIPS_SYMTABNO: symtabno = dynp->d_un.d_val; break; case DT_MIPS_GOTSYM: gotsym = dynp->d_un.d_val; break; } } i = GOT1_RESERVED_FOR_RTLD(got) ? 2 : 1; /* Relocate the local GOT entries */ got += i; for (; i < local_gotno; i++) { *got++ += relocbase; } sym = symtab + gotsym; /* Now do the global GOT entries */ for (i = gotsym; i < symtabno; i++) { *got = sym->st_value + relocbase; ++sym; ++got; } rellim = (const Elf_Rel *)((const char *)rel + relsz); for (; rel < rellim; rel++) { Elf_Word r_symndx, r_type; where = (void *)(relocbase + rel->r_offset); r_symndx = ELF_R_SYM(rel->r_info); r_type = ELF_R_TYPE(rel->r_info); switch (r_type & 0xff) { case R_TYPE(REL32): { const size_t rlen = ELF_R_NXTTYPE_64_P(r_type) ? sizeof(Elf_Sxword) : sizeof(Elf_Sword); Elf_Sxword old = load_ptr(where, rlen); Elf_Sxword val = old; #ifdef __mips_n64 assert(r_type == R_TYPE(REL32) || r_type == (R_TYPE(REL32)|(R_TYPE(64) << 8))); #endif assert(r_symndx < gotsym); sym = symtab + r_symndx; assert(ELF_ST_BIND(sym->st_info) == STB_LOCAL); val += relocbase; dbg("REL32/L(%p) %p -> %p in ", where, (void *)old, (void *)val); store_ptr(where, val, rlen); break; } case R_TYPE(GPREL32): case R_TYPE(NONE): break; default: abort(); break; } } } Elf_Addr _mips_rtld_bind(Obj_Entry *obj, Elf_Size reloff) { Elf_Addr *got = obj->pltgot; const Elf_Sym *def; const Obj_Entry *defobj; Elf_Addr *where; Elf_Addr target; RtldLockState lockstate; rlock_acquire(rtld_bind_lock, &lockstate); if (sigsetjmp(lockstate.env, 0) != 0) lock_upgrade(rtld_bind_lock, &lockstate); where = &got[obj->local_gotno + reloff - obj->gotsym]; def = find_symdef(reloff, obj, &defobj, SYMLOOK_IN_PLT, NULL, &lockstate); if (def == NULL) rtld_die(); target = (Elf_Addr)(defobj->relocbase + def->st_value); dbg("bind now/fixup at %s sym # %jd in %s --> was=%p new=%p", obj->path, (intmax_t)reloff, defobj->strtab + def->st_name, (void *)*where, (void *)target); if (!ld_bind_not) *where = target; lock_release(rtld_bind_lock, &lockstate); return (Elf_Addr)target; } int reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags, RtldLockState *lockstate) { const Elf_Rel *rel; const Elf_Rel *rellim; Elf_Addr *got = obj->pltgot; const Elf_Sym *sym, *def; const Obj_Entry *defobj; Elf_Word i; #ifdef SUPPORT_OLD_BROKEN_LD int broken; #endif /* The relocation for the dynamic loader has already been done. */ if (obj == obj_rtld) return (0); if ((flags & SYMLOOK_IFUNC) != 0) /* XXX not implemented */ return (0); #ifdef SUPPORT_OLD_BROKEN_LD broken = 0; sym = obj->symtab; for (i = 1; i < 12; i++) if (sym[i].st_info == ELF_ST_INFO(STB_LOCAL, STT_NOTYPE)) broken = 1; dbg("%s: broken=%d", obj->path, broken); #endif i = GOT1_RESERVED_FOR_RTLD(got) ? 2 : 1; /* Relocate the local GOT entries */ got += i; dbg("got:%p for %d entries adding %p", got, obj->local_gotno, obj->relocbase); for (; i < obj->local_gotno; i++) { *got += (Elf_Addr)obj->relocbase; got++; } sym = obj->symtab + obj->gotsym; dbg("got:%p for %d entries", got, obj->symtabno); /* Now do the global GOT entries */ for (i = obj->gotsym; i < obj->symtabno; i++) { dbg(" doing got %d sym %p (%s, %lx)", i - obj->gotsym, sym, sym->st_name + obj->strtab, (u_long) *got); #ifdef SUPPORT_OLD_BROKEN_LD if (ELF_ST_TYPE(sym->st_info) == STT_FUNC && broken && sym->st_shndx == SHN_UNDEF) { /* * XXX DANGER WILL ROBINSON! * You might think this is stupid, as it intentionally * defeats lazy binding -- and you'd be right. * Unfortunately, for lazy binding to work right, we * need to a way to force the GOT slots used for * function pointers to be resolved immediately. This * is supposed to be done automatically by the linker, * by not outputting a PLT slot and setting st_value * to 0 if there are non-PLT references, but older * versions of GNU ld do not do this. */ def = find_symdef(i, obj, &defobj, flags, NULL, lockstate); if (def == NULL) return -1; *got = def->st_value + (Elf_Addr)defobj->relocbase; } else #endif if (ELF_ST_TYPE(sym->st_info) == STT_FUNC && sym->st_value != 0 && sym->st_shndx == SHN_UNDEF) { /* * If there are non-PLT references to the function, * st_value should be 0, forcing us to resolve the * address immediately. * * XXX DANGER WILL ROBINSON! * The linker is not outputting PLT slots for calls to * functions that are defined in the same shared * library. This is a bug, because it can screw up * link ordering rules if the symbol is defined in * more than one module. For now, if there is a * definition, we fail the test above and force a full * symbol lookup. This means that all intra-module * calls are bound immediately. - mycroft, 2003/09/24 */ *got = sym->st_value + (Elf_Addr)obj->relocbase; if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) { dbg("Warning2, i:%d maps to relocbase address:%p", i, obj->relocbase); } } else if (sym->st_info == ELF_ST_INFO(STB_GLOBAL, STT_SECTION)) { /* Symbols with index SHN_ABS are not relocated. */ if (sym->st_shndx != SHN_ABS) { *got = sym->st_value + (Elf_Addr)obj->relocbase; if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) { dbg("Warning3, i:%d maps to relocbase address:%p", i, obj->relocbase); } } } else { /* TODO: add cache here */ def = find_symdef(i, obj, &defobj, flags, NULL, lockstate); if (def == NULL) { dbg("Warning4, can't find symbole %d", i); return -1; } *got = def->st_value + (Elf_Addr)defobj->relocbase; if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) { dbg("Warning4, i:%d maps to relocbase address:%p", i, obj->relocbase); dbg("via first obj symbol %s", obj->strtab + obj->symtab[i].st_name); dbg("found in obj %p:%s", defobj, defobj->path); } } dbg(" --> now %lx", (u_long) *got); ++sym; ++got; } got = obj->pltgot; rellim = (const Elf_Rel *)((const char *)obj->rel + obj->relsize); for (rel = obj->rel; rel < rellim; rel++) { Elf_Word r_symndx, r_type; void *where; where = obj->relocbase + rel->r_offset; r_symndx = ELF_R_SYM(rel->r_info); r_type = ELF_R_TYPE(rel->r_info); switch (r_type & 0xff) { case R_TYPE(NONE): break; case R_TYPE(REL32): { /* 32-bit PC-relative reference */ const size_t rlen = ELF_R_NXTTYPE_64_P(r_type) ? sizeof(Elf_Sxword) : sizeof(Elf_Sword); Elf_Sxword old = load_ptr(where, rlen); Elf_Sxword val = old; def = obj->symtab + r_symndx; if (r_symndx >= obj->gotsym) { val += got[obj->local_gotno + r_symndx - obj->gotsym]; dbg("REL32/G(%p) %p --> %p (%s) in %s", where, (void *)old, (void *)val, obj->strtab + def->st_name, obj->path); } else { /* * XXX: ABI DIFFERENCE! * * Old NetBSD binutils would generate shared * libs with section-relative relocations being * already adjusted for the start address of * 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; dbg("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; } case R_TYPE(COPY): /* * These are deferred until all other relocations have * been done. All we do here is make sure that the * COPY relocation is not in a shared library. They * are allowed only in executable files. */ if (!obj->mainprog) { _rtld_error("%s: Unexpected R_MIPS_COPY " "relocation in shared library", obj->path); return (-1); } break; #ifdef __mips_n64 case R_TYPE(TLS_DTPMOD64): #else case R_TYPE(TLS_DTPMOD32): #endif { const size_t rlen = sizeof(Elf_Addr); Elf_Addr old = load_ptr(where, rlen); Elf_Addr val = old; def = find_symdef(r_symndx, obj, &defobj, flags, NULL, lockstate); if (def == NULL) return -1; val += (Elf_Addr)defobj->tlsindex; store_ptr(where, val, rlen); dbg("DTPMOD %s in %s %p --> %p in %s", obj->strtab + obj->symtab[r_symndx].st_name, obj->path, (void *)old, (void*)val, defobj->path); break; } #ifdef __mips_n64 case R_TYPE(TLS_DTPREL64): #else case R_TYPE(TLS_DTPREL32): #endif { const size_t rlen = sizeof(Elf_Addr); Elf_Addr old = load_ptr(where, rlen); Elf_Addr val = old; def = find_symdef(r_symndx, obj, &defobj, flags, NULL, lockstate); if (def == NULL) return -1; if (!defobj->tls_static && !allocate_tls_offset(obj)) return -1; val += (Elf_Addr)def->st_value - TLS_DTV_OFFSET; store_ptr(where, val, rlen); dbg("DTPREL %s in %s %p --> %p in %s", obj->strtab + obj->symtab[r_symndx].st_name, obj->path, (void*)old, (void *)val, defobj->path); break; } #ifdef __mips_n64 case R_TYPE(TLS_TPREL64): #else case R_TYPE(TLS_TPREL32): #endif { const size_t rlen = sizeof(Elf_Addr); Elf_Addr old = load_ptr(where, rlen); Elf_Addr val = old; def = find_symdef(r_symndx, obj, &defobj, flags, NULL, lockstate); if (def == NULL) return -1; if (!defobj->tls_static && !allocate_tls_offset(obj)) return -1; val += (Elf_Addr)(def->st_value + defobj->tlsoffset - TLS_TP_OFFSET - TLS_TCB_SIZE); store_ptr(where, val, rlen); dbg("TPREL %s in %s %p --> %p in %s", obj->strtab + obj->symtab[r_symndx].st_name, obj->path, (void*)old, (void *)val, defobj->path); break; } default: dbg("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; } /* * Process the PLT relocations. */ int reloc_plt(Obj_Entry *obj, int flags __unused, RtldLockState *lockstate __unused) { const Elf_Rel *rellim; const Elf_Rel *rel; rellim = (const Elf_Rel *)((const char *)obj->pltrel + obj->pltrelsize); for (rel = obj->pltrel; rel < rellim; rel++) { Elf_Addr *where; switch (ELF_R_TYPE(rel->r_info)) { case R_MIPS_JUMP_SLOT: where = (Elf_Addr *)(obj->relocbase + rel->r_offset); *where += (Elf_Addr )obj->relocbase; break; default: _rtld_error("Unknown relocation type %u in PLT", (unsigned int)ELF_R_TYPE(rel->r_info)); return (-1); } } return (0); } /* * LD_BIND_NOW was set - force relocation for all jump slots */ int reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate) { const Obj_Entry *defobj; const Elf_Rel *rellim; const Elf_Rel *rel; const Elf_Sym *def; rellim = (const Elf_Rel *)((const char *)obj->pltrel + obj->pltrelsize); for (rel = obj->pltrel; rel < rellim; rel++) { Elf_Addr *where; switch (ELF_R_TYPE(rel->r_info)) { case R_MIPS_JUMP_SLOT: def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT | flags, NULL, lockstate); if (def == NULL) { dbg("reloc_jmpslots: sym not found"); return (-1); } where = (Elf_Addr *)(obj->relocbase + rel->r_offset); *where = (Elf_Addr)(defobj->relocbase + def->st_value); break; default: _rtld_error("Unknown relocation type %u in PLT", (unsigned int)ELF_R_TYPE(rel->r_info)); return (-1); } } return (0); } int reloc_iresolve(Obj_Entry *obj __unused, struct Struct_RtldLockState *lockstate __unused) { /* XXX not implemented */ return (0); } int reloc_iresolve_nonplt(Obj_Entry *obj __unused, struct Struct_RtldLockState *lockstate __unused) { /* XXX not implemented */ return (0); } int reloc_gnu_ifunc(Obj_Entry *obj __unused, int flags __unused, struct Struct_RtldLockState *lockstate __unused) { /* XXX not implemented */ return (0); } Elf_Addr reloc_jmpslot(Elf_Addr *where, Elf_Addr target, const Obj_Entry *defobj __unused, const Obj_Entry *obj __unused, const Elf_Rel *rel) { assert(ELF_R_TYPE(rel->r_info) == R_MIPS_JUMP_SLOT); if (*where != target && !ld_bind_not) *where = target; return (target); } void ifunc_init(Elf_Auxinfo aux_info[__min_size(AT_COUNT)] __unused) { } void allocate_initial_tls(Obj_Entry *objs) { /* * Fix the size of the static TLS block by using the maximum * offset allocated so far and adding a bit for dynamic modules to * use. */ tls_static_space = tls_last_offset + tls_last_size + RTLD_STATIC_TLS_EXTRA; _tcb_set(allocate_tls(objs, NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN)); } void * __tls_get_addr(tls_index* ti) { uintptr_t **dtvp; char *p; dtvp = &_tcb_get()->tcb_dtv; p = tls_get_addr_common(dtvp, ti->ti_module, ti->ti_offset); return (p + TLS_DTV_OFFSET); }