/* $NetBSD: ppc_reloc.c,v 1.10 2001/09/10 06:09:41 mycroft Exp $ */ /*- * 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. * * $FreeBSD$ */ #include #include #include #include #include #include #include #include #include "debug.h" #include "rtld.h" #define _ppc_ha(x) ((((u_int32_t)(x) & 0x8000) ? \ ((u_int32_t)(x) + 0x10000) : (u_int32_t)(x)) >> 16) #define _ppc_la(x) ((u_int32_t)(x) & 0xffff) /* * 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 *) ((caddr_t) dstobj->rela + dstobj->relasize); for (rela = dstobj->rela; rela < relalim; rela++) { void *dstaddr; const Elf_Sym *dstsym; const char *name; unsigned long hash; size_t size; const void *srcaddr; const Elf_Sym *srcsym = NULL; Obj_Entry *srcobj; const Ver_Entry *ve; 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; hash = elf_hash(name); size = dstsym->st_size; ve = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info)); for (srcobj = dstobj->next; srcobj != NULL; srcobj = srcobj->next) { if ((srcsym = symlook_obj(name, hash, srcobj, ve, 0)) != NULL) { break; } } if (srcobj == NULL) { _rtld_error("Undefined symbol \"%s\" " " referenced from COPY" " relocation in %s", name, dstobj->path); return (-1); } srcaddr = (const void *) (srcobj->relocbase+srcsym->st_value); memcpy(dstaddr, srcaddr, size); dbg("copy_reloc: src=%p,dst=%p,size=%d\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 = 0, *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 *)((caddr_t)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, Obj_Entry *obj, const Elf_Rela *rela, SymCache *cache) { Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); const Elf_Sym *def; const Obj_Entry *defobj; Elf_Addr tmp; switch (ELF_R_TYPE(rela->r_info)) { case R_PPC_NONE: break; case R_PPC_ADDR32: /* word32 S + A */ case R_PPC_GLOB_DAT: /* word32 S + A */ def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, false, cache); if (def == NULL) { return (-1); } tmp = (Elf_Addr)(defobj->relocbase + def->st_value + rela->r_addend); /* Don't issue write if unnecessary; avoid COW page fault */ if (*where != tmp) { *where = tmp; } break; case R_PPC_RELATIVE: /* word32 B + A */ tmp = (Elf_Addr)(obj->relocbase + rela->r_addend); /* As above, don't issue write unnecessarily */ if (*where != tmp) { *where = tmp; } 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_JMP_SLOT: /* * These will be handled by the plt/jmpslot routines */ break; case R_PPC_DTPMOD32: def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, false, cache); if (def == NULL) return (-1); *where = (Elf_Addr) defobj->tlsindex; break; case R_PPC_TPREL32: def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, false, cache); if (def == NULL) return (-1); /* * 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_done) { if (!allocate_tls_offset((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); break; case R_PPC_DTPREL32: def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, false, cache); if (def == NULL) return (-1); *where += (Elf_Addr)(def->st_value + rela->r_addend - TLS_DTV_OFFSET); break; default: _rtld_error("%s: Unsupported relocation type %d" " 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) { const Elf_Rela *relalim; const Elf_Rela *rela; SymCache *cache; int bytes = obj->nchains * 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(). */ cache = mmap(NULL, bytes, PROT_READ|PROT_WRITE, MAP_ANON, -1, 0); if (cache == MAP_FAILED) cache = NULL; /* * From the SVR4 PPC ABI: * "The PowerPC family uses only the Elf32_Rela relocation * entries with explicit addends." */ relalim = (const Elf_Rela *)((caddr_t)obj->rela + obj->relasize); for (rela = obj->rela; rela < relalim; rela++) { if (reloc_nonplt_object(obj_rtld, obj, rela, cache) < 0) goto done; } r = 0; done: if (cache) { munmap(cache, bytes); } return (r); } /* * Initialise a PLT slot to the resolving trampoline */ static int reloc_plt_object(Obj_Entry *obj, const Elf_Rela *rela) { Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset); Elf_Addr *pltresolve; Elf_Addr distance; int reloff; reloff = rela - obj->pltrela; if ((reloff < 0) || (reloff >= 0x8000)) { return (-1); } pltresolve = obj->pltgot + 8; distance = (Elf_Addr)pltresolve - (Elf_Addr)(where + 1); dbg(" reloc_plt_object: where=%p,pltres=%p,reloff=%x,distance=%x", (void *)where, (void *)pltresolve, reloff, distance); /* li r11,reloff */ /* b pltresolve */ where[0] = 0x39600000 | reloff; where[1] = 0x48000000 | (distance & 0x03fffffc); /* * The icache will be sync'd in init_pltgot, which is called * after all the slots have been updated */ return (0); } /* * Process the PLT relocations. */ int reloc_plt(Obj_Entry *obj) { const Elf_Rela *relalim; const Elf_Rela *rela; if (obj->pltrelasize != 0) { relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize); for (rela = obj->pltrela; rela < relalim; rela++) { 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) { 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 *)((char *)obj->pltrela + obj->pltrelasize); for (rela = obj->pltrela; rela < relalim; rela++) { 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, true, NULL); if (def == NULL) { dbg("reloc_jmpslots: sym not found"); return (-1); } target = (Elf_Addr)(defobj->relocbase + def->st_value); #if 0 /* PG XXX */ dbg("\"%s\" in \"%s\" --> %p in \"%s\"", defobj->strtab + def->st_name, basename(obj->path), (void *)target, basename(defobj->path)); #endif reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *) rela); } obj->jmpslots_done = true; return (0); } /* * Update the value of a PLT jump slot. Branch directly to the target if * it is within +/- 32Mb, otherwise go indirectly via the pltcall * trampoline call and jump table. */ Elf_Addr reloc_jmpslot(Elf_Addr *wherep, Elf_Addr target, const Obj_Entry *defobj, const Obj_Entry *obj, const Elf_Rel *rel) { Elf_Addr offset; const Elf_Rela *rela = (const Elf_Rela *) rel; dbg(" reloc_jmpslot: where=%p, target=%p", (void *)wherep, (void *)target); /* * At the PLT entry pointed at by `wherep', construct * a direct transfer to the now fully resolved function * address. */ offset = target - (Elf_Addr)wherep; if (abs(offset) < 32*1024*1024) { /* inside 32MB? */ /* b value # branch directly */ *wherep = 0x48000000 | (offset & 0x03fffffc); __syncicache(wherep, 4); } else { Elf_Addr *pltcall, *jmptab; int distance; int N = obj->pltrelasize / sizeof(Elf_Rela); int reloff = rela - obj->pltrela; if ((reloff < 0) || (reloff >= 0x8000)) { return (-1); } pltcall = obj->pltgot; dbg(" reloc_jmpslot: indir, reloff=%d, N=%d\n", reloff, N); jmptab = obj->pltgot + 18 + N * 2; jmptab[reloff] = target; distance = (Elf_Addr)pltcall - (Elf_Addr)(wherep + 1); /* li r11,reloff */ /* b pltcall # use indirect pltcall routine */ wherep[0] = 0x39600000 | reloff; wherep[1] = 0x48000000 | (distance & 0x03fffffc); __syncicache(wherep, 8); } return (target); } /* * Setup the plt glue routines. */ #define PLTCALL_SIZE 20 #define PLTRESOLVE_SIZE 24 void init_pltgot(Obj_Entry *obj) { Elf_Word *pltcall, *pltresolve; Elf_Word *jmptab; int N = obj->pltrelasize / sizeof(Elf_Rela); pltcall = obj->pltgot; if (pltcall == NULL) { return; } /* * From the SVR4 PPC ABI: * * 'The first 18 words (72 bytes) of the PLT are reserved for * use by the dynamic linker. * ... * 'If the executable or shared object requires N procedure * linkage table entries, the link editor shall reserve 3*N * words (12*N bytes) following the 18 reserved words. The * first 2*N of these words are the procedure linkage table * entries themselves. The static linker directs calls to bytes * (72 + (i-1)*8), for i between 1 and N inclusive. The remaining * N words (4*N bytes) are reserved for use by the dynamic linker.' */ /* * Copy the absolute-call assembler stub into the first part of * the reserved PLT area. */ memcpy(pltcall, _rtld_powerpc_pltcall, PLTCALL_SIZE); /* * Determine the address of the jumptable, which is the dyn-linker * reserved area after the call cells. Write the absolute address * of the jumptable into the absolute-call assembler code so it * can determine this address. */ jmptab = pltcall + 18 + N * 2; pltcall[1] |= _ppc_ha(jmptab); /* addis 11,11,jmptab@ha */ pltcall[2] |= _ppc_la(jmptab); /* lwz 11,jmptab@l(11) */ /* * Skip down 32 bytes into the initial reserved area and copy * in the standard resolving assembler call. Into this assembler, * insert the absolute address of the _rtld_bind_start routine * and the address of the relocation object. */ pltresolve = obj->pltgot + 8; memcpy(pltresolve, _rtld_powerpc_pltresolve, PLTRESOLVE_SIZE); pltresolve[0] |= _ppc_ha(_rtld_bind_start); pltresolve[1] |= _ppc_la(_rtld_bind_start); pltresolve[3] |= _ppc_ha(obj); pltresolve[4] |= _ppc_la(obj); /* * Sync the icache for the byte range represented by the * trampoline routines and call slots. */ __syncicache(pltcall, 72 + N * 8); } void allocate_initial_tls(Obj_Entry *list) { register Elf_Addr **tp __asm__("r2"); Elf_Addr **_tp; /* * 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; _tp = (Elf_Addr **) ((char *) allocate_tls(list, NULL, TLS_TCB_SIZE, 8) + TLS_TP_OFFSET + TLS_TCB_SIZE); /* * XXX gcc seems to ignore 'tp = _tp;' */ __asm __volatile("mr %0,%1" : "=r"(tp) : "r"(_tp)); } void* __tls_get_addr(tls_index* ti) { register Elf_Addr **tp __asm__("r2"); char *p; p = tls_get_addr_common((Elf_Addr**)((Elf_Addr)tp - TLS_TP_OFFSET - TLS_TCB_SIZE), ti->ti_module, ti->ti_offset); return (p + TLS_DTV_OFFSET); }