/* $NetBSD: ppc_reloc.c,v 1.10 2001/09/10 06:09:41 mycroft Exp $ */ /*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (C) 1998 Tsubai Masanari * 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 #include "debug.h" #include "rtld.h" #if !defined(_CALL_ELF) || _CALL_ELF == 1 struct funcdesc { Elf_Addr addr; Elf_Addr toc; Elf_Addr env; }; #endif bool arch_digest_dynamic(struct Struct_Obj_Entry *obj, const Elf_Dyn *dynp) { if (dynp->d_tag == DT_PPC64_GLINK) { obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); return (true); } return (false); } /* * Process the R_PPC_COPY relocations */ int do_copy_relocations(Obj_Entry *dstobj) { const Elf_Rela *relalim; const Elf_Rela *rela; /* * COPY relocs are invalid outside of the main program */ assert(dstobj->mainprog); relalim = (const Elf_Rela *)((const char *) dstobj->rela + dstobj->relasize); for (rela = dstobj->rela; rela < relalim; rela++) { void *dstaddr; const Elf_Sym *dstsym; const char *name; size_t size; const void *srcaddr; const Elf_Sym *srcsym = NULL; const Obj_Entry *srcobj, *defobj; SymLook req; int res; if (ELF_R_TYPE(rela->r_info) != R_PPC_COPY) { continue; } dstaddr = (void *)(dstobj->relocbase + rela->r_offset); dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info); name = dstobj->strtab + dstsym->st_name; size = dstsym->st_size; symlook_init(&req, name); req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->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); dbg("copy_reloc: src=%p,dst=%p,size=%zd\n",srcaddr,dstaddr,size); } return (0); } /* * Perform early relocation of the run-time linker image */ void reloc_non_plt_self(Elf_Dyn *dynp, Elf_Addr relocbase) { const Elf_Rela *rela = NULL, *relalim; Elf_Addr relasz = 0; Elf_Addr *where; /* * Extract the rela/relasz values from the dynamic section */ for (; dynp->d_tag != DT_NULL; dynp++) { switch (dynp->d_tag) { case DT_RELA: rela = (const Elf_Rela *)(relocbase+dynp->d_un.d_ptr); break; case DT_RELASZ: relasz = dynp->d_un.d_val; break; } } /* * Relocate these values */ relalim = (const Elf_Rela *)((const char *)rela + relasz); for (; rela < relalim; rela++) { where = (Elf_Addr *)(relocbase + rela->r_offset); *where = (Elf_Addr)(relocbase + rela->r_addend); } } /* * Relocate a non-PLT object with addend. */ static int reloc_nonplt_object(Obj_Entry *obj_rtld __unused, Obj_Entry *obj, const Elf_Rela *rela, SymCache *cache, int flags, RtldLockState *lockstate) { const Elf_Sym *def = NULL; const Obj_Entry *defobj; Elf_Addr *where, symval = 0; /* * First, resolve symbol for relocations which * reference symbols. */ switch (ELF_R_TYPE(rela->r_info)) { case R_PPC64_UADDR64: /* doubleword64 S + A */ case R_PPC64_ADDR64: case R_PPC_GLOB_DAT: case R_PPC64_DTPMOD64: case R_PPC64_TPREL64: case R_PPC64_DTPREL64: def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, flags, cache, lockstate); if (def == NULL) { return (-1); } /* * If symbol is IFUNC, only perform relocation * when caller allowed it by passing * SYMLOOK_IFUNC flag. Skip the relocations * otherwise. * * Also error out in case IFUNC relocations * are specified for TLS, which cannot be * usefully interpreted. */ if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { switch (ELF_R_TYPE(rela->r_info)) { case R_PPC64_UADDR64: case R_PPC64_ADDR64: case R_PPC_GLOB_DAT: if ((flags & SYMLOOK_IFUNC) == 0) { dbg("Non-PLT reference to IFUNC found!"); obj->non_plt_gnu_ifunc = true; return (0); } symval = (Elf_Addr)rtld_resolve_ifunc( defobj, def); break; default: _rtld_error("%s: IFUNC for TLS reloc", obj->path); return (-1); } } else { if ((flags & SYMLOOK_IFUNC) != 0) return (0); symval = (Elf_Addr)defobj->relocbase + def->st_value; } break; default: if ((flags & SYMLOOK_IFUNC) != 0) return (0); } where = (Elf_Addr *)(obj->relocbase + rela->r_offset); switch (ELF_R_TYPE(rela->r_info)) { case R_PPC_NONE: break; case R_PPC64_UADDR64: case R_PPC64_ADDR64: case R_PPC_GLOB_DAT: /* Don't issue write if unnecessary; avoid COW page fault */ if (*where != symval + rela->r_addend) { *where = symval + rela->r_addend; } break; case R_PPC64_DTPMOD64: *where = (Elf_Addr) defobj->tlsindex; break; case R_PPC64_TPREL64: /* * We lazily allocate offsets for static TLS as we * see the first relocation that references the * TLS block. This allows us to support (small * amounts of) static TLS in dynamically loaded * modules. If we run out of space, we generate an * error. */ if (!defobj->tls_static) { if (!allocate_tls_offset( __DECONST(Obj_Entry *, defobj))) { _rtld_error("%s: No space available for static " "Thread Local Storage", obj->path); return (-1); } } *(Elf_Addr **)where = *where * sizeof(Elf_Addr) + (Elf_Addr *)(def->st_value + rela->r_addend + defobj->tlsoffset - TLS_TP_OFFSET - TLS_TCB_SIZE); break; case R_PPC64_DTPREL64: *where += (Elf_Addr)(def->st_value + rela->r_addend - TLS_DTV_OFFSET); break; case R_PPC_RELATIVE: /* doubleword64 B + A */ symval = (Elf_Addr)(obj->relocbase + rela->r_addend); /* As above, don't issue write unnecessarily */ if (*where != symval) { *where = symval; } break; case R_PPC_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_COPY " " relocation in shared library", obj->path); return (-1); } break; case R_PPC_IRELATIVE: /* * These will be handled by reloc_iresolve(). */ obj->irelative = true; break; case R_PPC_JMP_SLOT: /* * These will be handled by the plt/jmpslot routines */ break; default: _rtld_error("%s: Unsupported relocation type %ld" " in non-PLT relocations\n", obj->path, ELF_R_TYPE(rela->r_info)); return (-1); } return (0); } /* * Process non-PLT relocations */ int reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags, RtldLockState *lockstate) { const Elf_Rela *relalim; const Elf_Rela *rela; const Elf_Phdr *phdr; SymCache *cache; int bytes = obj->dynsymcount * sizeof(SymCache); int r = -1; /* * The dynamic loader may be called from a thread, we have * limited amounts of stack available so we cannot use alloca(). */ if (obj != obj_rtld) { cache = mmap(NULL, bytes, PROT_READ|PROT_WRITE, MAP_ANON, -1, 0); if (cache == MAP_FAILED) cache = NULL; } else cache = NULL; /* * From the SVR4 PPC ABI: * "The PowerPC family uses only the Elf32_Rela relocation * entries with explicit addends." */ relalim = (const Elf_Rela *)((const char *)obj->rela + obj->relasize); for (rela = obj->rela; rela < relalim; rela++) { if (reloc_nonplt_object(obj_rtld, obj, rela, cache, flags, lockstate) < 0) goto done; } r = 0; done: if (cache) munmap(cache, bytes); /* * Synchronize icache for executable segments in case we made * any changes. */ for (phdr = obj->phdr; phdr < obj->phdr + obj->phnum; phdr++) { if (phdr->p_type == PT_LOAD && (phdr->p_flags & PF_X) != 0) { __syncicache(obj->relocbase + phdr->p_vaddr, phdr->p_memsz); } } return (r); } /* * Initialise a PLT slot to the resolving trampoline */ static int reloc_plt_object(Obj_Entry *obj, const Elf_Rela *rela) { Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); long reloff; reloff = rela - obj->pltrela; dbg(" reloc_plt_object: where=%p,reloff=%lx,glink=%#lx", (void *)where, reloff, obj->glink); #if !defined(_CALL_ELF) || _CALL_ELF == 1 /* Glink code is 3 instructions after the first 32k, 2 before */ *where = (Elf_Addr)obj->glink + 32 + 8*((reloff < 0x8000) ? reloff : 0x8000) + 12*((reloff < 0x8000) ? 0 : (reloff - 0x8000)); #else /* 64-Bit ELF V2 ABI Specification, sec. 4.2.5.3. */ *where = (Elf_Addr)obj->glink + 4*reloff + 32; #endif return (0); } /* * Process the PLT relocations. */ int reloc_plt(Obj_Entry *obj, int flags __unused, RtldLockState *lockstate __unused) { const Elf_Rela *relalim; const Elf_Rela *rela; if (obj->pltrelasize != 0) { relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize); for (rela = obj->pltrela; rela < relalim; rela++) { #if defined(_CALL_ELF) && _CALL_ELF == 2 if (ELF_R_TYPE(rela->r_info) == R_PPC_IRELATIVE) { dbg("ABI violation - found IRELATIVE in the PLT."); obj->irelative = true; continue; } #endif /* * PowerPC(64) .rela.plt is composed of an array of * R_PPC_JMP_SLOT relocations. Unlike other platforms, * this is the ONLY relocation type that is valid here. */ assert(ELF_R_TYPE(rela->r_info) == R_PPC_JMP_SLOT); if (reloc_plt_object(obj, rela) < 0) { 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_Rela *relalim; const Elf_Rela *rela; const Elf_Sym *def; Elf_Addr *where; Elf_Addr target; relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize); for (rela = obj->pltrela; rela < relalim; rela++) { /* This isn't actually a jump slot, ignore it. */ if (ELF_R_TYPE(rela->r_info) == R_PPC_IRELATIVE) continue; assert(ELF_R_TYPE(rela->r_info) == R_PPC_JMP_SLOT); where = (Elf_Addr *)(obj->relocbase + rela->r_offset); def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, SYMLOOK_IN_PLT | flags, NULL, lockstate); if (def == NULL) { dbg("reloc_jmpslots: sym not found"); return (-1); } target = (Elf_Addr)(defobj->relocbase + def->st_value); if (def == &sym_zero) { /* Zero undefined weak symbols */ #if !defined(_CALL_ELF) || _CALL_ELF == 1 bzero(where, sizeof(struct funcdesc)); #else *where = 0; #endif } else { if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { /* LD_BIND_NOW, ifunc in shared lib.*/ obj->gnu_ifunc = true; continue; } reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *) rela); } } obj->jmpslots_done = true; return (0); } /* * Update the value of a PLT jump slot. */ Elf_Addr reloc_jmpslot(Elf_Addr *wherep, Elf_Addr target, const Obj_Entry *defobj __unused, const Obj_Entry *obj __unused, const Elf_Rel *rel __unused) { /* * At the PLT entry pointed at by `wherep', construct * a direct transfer to the now fully resolved function * address. */ #if !defined(_CALL_ELF) || _CALL_ELF == 1 dbg(" reloc_jmpslot: where=%p, target=%p (%#lx + %#lx)", (void *)wherep, (void *)target, *(Elf_Addr *)target, (Elf_Addr)defobj->relocbase); if (ld_bind_not) goto out; /* * For the trampoline, the second two elements of the function * descriptor are unused, so we are fine replacing those at any time * with the real ones with no thread safety implications. However, we * need to make sure the main entry point pointer ([0]) is seen to be * modified *after* the second two elements. This can't be done in * general, since there are no barriers in the reading code, but put in * some isyncs to at least make it a little better. */ memcpy(wherep, (void *)target, sizeof(struct funcdesc)); wherep[2] = ((Elf_Addr *)target)[2]; wherep[1] = ((Elf_Addr *)target)[1]; __asm __volatile ("isync" : : : "memory"); wherep[0] = ((Elf_Addr *)target)[0]; __asm __volatile ("isync" : : : "memory"); if (((struct funcdesc *)(wherep))->addr < (Elf_Addr)defobj->relocbase) { /* * It is possible (LD_BIND_NOW) that the function * descriptor we are copying has not yet been relocated. * If this happens, fix it. Don't worry about threading in * this case since LD_BIND_NOW makes it irrelevant. */ ((struct funcdesc *)(wherep))->addr += (Elf_Addr)defobj->relocbase; ((struct funcdesc *)(wherep))->toc += (Elf_Addr)defobj->relocbase; } #else dbg(" reloc_jmpslot: where=%p, target=%p", (void *)wherep, (void *)target); assert(target >= (Elf_Addr)defobj->relocbase); if (ld_bind_not) goto out; if (*wherep != target) *wherep = target; #endif out: return (target); } int reloc_iresolve(Obj_Entry *obj, struct Struct_RtldLockState *lockstate) { /* * Since PLT slots on PowerPC64 are always R_PPC_JMP_SLOT, * R_PPC_IRELATIVE is in RELA. */ #if !defined(_CALL_ELF) || _CALL_ELF == 1 (void)(obj); (void)(lockstate); /* XXX not implemented */ return (0); #else const Elf_Rela *relalim; const Elf_Rela *rela; Elf_Addr *where, target, *ptr; if (!obj->irelative) return (0); relalim = (const Elf_Rela *)((const char *)obj->rela + obj->relasize); for (rela = obj->rela; rela < relalim; rela++) { if (ELF_R_TYPE(rela->r_info) == R_PPC_IRELATIVE) { ptr = (Elf_Addr *)(obj->relocbase + rela->r_addend); where = (Elf_Addr *)(obj->relocbase + rela->r_offset); lock_release(rtld_bind_lock, lockstate); target = call_ifunc_resolver(ptr); wlock_acquire(rtld_bind_lock, lockstate); *where = target; } } /* * XXX Remove me when lld is fixed! * LLD currently makes illegal relocations in the PLT. */ relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize); for (rela = obj->pltrela; rela < relalim; rela++) { if (ELF_R_TYPE(rela->r_info) == R_PPC_IRELATIVE) { ptr = (Elf_Addr *)(obj->relocbase + rela->r_addend); where = (Elf_Addr *)(obj->relocbase + rela->r_offset); lock_release(rtld_bind_lock, lockstate); target = call_ifunc_resolver(ptr); wlock_acquire(rtld_bind_lock, lockstate); *where = target; } } obj->irelative = false; return (0); #endif } int reloc_gnu_ifunc(Obj_Entry *obj __unused, int flags __unused, struct Struct_RtldLockState *lockstate __unused) { #if !defined(_CALL_ELF) || _CALL_ELF == 1 _rtld_error("reloc_gnu_ifunc(): Not implemented!"); /* XXX not implemented */ return (-1); #else const Elf_Rela *relalim; const Elf_Rela *rela; Elf_Addr *where, target; const Elf_Sym *def; const Obj_Entry *defobj; if (!obj->gnu_ifunc) return (0); relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize); for (rela = obj->pltrela; rela < relalim; rela++) { if (ELF_R_TYPE(rela->r_info) == R_PPC_JMP_SLOT) { where = (Elf_Addr *)(obj->relocbase + rela->r_offset); def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, SYMLOOK_IN_PLT | flags, NULL, lockstate); if (def == NULL) return (-1); if (ELF_ST_TYPE(def->st_info) != STT_GNU_IFUNC) continue; lock_release(rtld_bind_lock, lockstate); target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); wlock_acquire(rtld_bind_lock, lockstate); reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela); } } obj->gnu_ifunc = false; return (0); #endif } int reloc_iresolve_nonplt(Obj_Entry *obj __unused, struct Struct_RtldLockState *lockstate __unused) { return (0); } void init_pltgot(Obj_Entry *obj) { Elf_Addr *pltcall; pltcall = obj->pltgot; if (pltcall == NULL) { return; } #if defined(_CALL_ELF) && _CALL_ELF == 2 pltcall[0] = (Elf_Addr)&_rtld_bind_start; pltcall[1] = (Elf_Addr)obj; #else memcpy(pltcall, _rtld_bind_start, sizeof(struct funcdesc)); pltcall[2] = (Elf_Addr)obj; #endif } /* * Actual values are 32 bit. */ u_long cpu_features; u_long cpu_features2; void powerpc64_abi_variant_hook(Elf_Auxinfo** aux_info) { /* * Since aux_info[] is easier to work with than aux, go ahead and * initialize cpu_features / cpu_features2. */ cpu_features = -1UL; cpu_features2 = -1UL; if (aux_info[AT_HWCAP] != NULL) cpu_features = (uint32_t)aux_info[AT_HWCAP]->a_un.a_val; if (aux_info[AT_HWCAP2] != NULL) cpu_features2 = (uint32_t)aux_info[AT_HWCAP2]->a_un.a_val; } void ifunc_init(Elf_Auxinfo *aux_info[__min_size(AT_COUNT)] __unused) { } void allocate_initial_tls(Obj_Entry *list) { /* * 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 + ld_static_tls_extra; _tcb_set(allocate_tls(list, NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN)); } void* __tls_get_addr(tls_index* ti) { return (tls_get_addr_common(_tcb_get(), ti->ti_module, ti->ti_offset + TLS_DTV_OFFSET)); } void arch_fix_auxv(Elf_Auxinfo *aux, Elf_Auxinfo *aux_info[]) { Elf_Auxinfo *auxp; for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { if (auxp->a_type == 23) /* AT_STACKPROT */ return; } /* Remap from old-style auxv numbers. */ aux_info[23] = aux_info[21]; /* AT_STACKPROT */ aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ aux_info[19] = aux_info[17]; /* AT_NCPUS */ aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ aux_info[15] = aux_info[13]; /* AT_EXECPATH */ aux_info[13] = NULL; /* AT_GID */ aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ aux_info[16] = aux_info[14]; /* AT_CANARY */ aux_info[14] = NULL; /* AT_EGID */ }