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+/* $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 <sys/param.h>
+#include <sys/mman.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <machine/cpu.h>
+
+#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;
+
+ 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;
+
+ for (srcobj = dstobj->next; srcobj != NULL;
+ srcobj = srcobj->next) {
+ if ((srcsym = symlook_obj(name, hash, srcobj, false))
+ != 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;
+
+ 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;
+ }
+ if (cache != NULL) {
+ memset(cache, 0, obj->nchains * sizeof(SymCache));
+ }
+
+ /*
+ * 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);
+}
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