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- /*
- * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
- *
- * Lots of code copied from ../i386/elfinterp.c, so:
- * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
- * David Engel, Hongjiu Lu and Mitch D'Souza
- * Copyright (C) 2001-2002, Erik Andersen
- * All rights reserved.
- *
- * Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
- */
- #include "ldso.h"
- #ifdef __A7__
- #define ARC_PLT_SIZE 12
- #else
- #define ARC_PLT_SIZE 16
- #endif
- unsigned long
- _dl_linux_resolver(struct elf_resolve *tpnt, unsigned int plt_pc)
- {
- ELF_RELOC *this_reloc, *rel_base;
- char *strtab, *symname, *new_addr;
- ElfW(Sym) *symtab;
- int symtab_index;
- unsigned int *got_addr;
- unsigned long plt_base;
- int plt_idx;
- /* start of .rela.plt */
- rel_base = (ELF_RELOC *)(tpnt->dynamic_info[DT_JMPREL]);
- /* starts of .plt (addr of PLT0) */
- plt_base = tpnt->dynamic_info[DT_PLTGOT];
- /*
- * compute the idx of the yet-unresolved PLT entry in .plt
- * Same idx will be used to find the relo entry in .rela.plt
- */
- plt_idx = (plt_pc - plt_base)/ARC_PLT_SIZE - 2; /* ignoring 2 dummy PLTs */
- this_reloc = rel_base + plt_idx;
- symtab_index = ELF_R_SYM(this_reloc->r_info);
- symtab = (ElfW(Sym) *)(intptr_t) (tpnt->dynamic_info[DT_SYMTAB]);
- strtab = (char *) (tpnt->dynamic_info[DT_STRTAB]);
- symname= strtab + symtab[symtab_index].st_name;
- /* relo-offset to fixup, shd be a .got entry */
- got_addr = (unsigned int *)(this_reloc->r_offset + tpnt->loadaddr);
- /* Get the address of the GOT entry */
- new_addr = _dl_find_hash(symname, &_dl_loaded_modules->symbol_scope, tpnt,
- ELF_RTYPE_CLASS_PLT, NULL);
- if (unlikely(!new_addr)) {
- _dl_dprintf(2, "%s: can't resolve symbol '%s'\n", _dl_progname, symname);
- _dl_exit(1);
- }
- #if defined __SUPPORT_LD_DEBUG__
- if (_dl_debug_bindings) {
- _dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname);
- if (_dl_debug_detail)
- _dl_dprintf(_dl_debug_file, "\n\tpatched %x ==> %pc @ %pl\n",
- *got_addr, new_addr, got_addr);
- }
- if (!_dl_debug_nofixups)
- *got_addr = (unsigned int)new_addr;
- #else
- /* Update the .got entry with the runtime address of symbol */
- *got_addr = (unsigned int)new_addr;
- #endif
- /*
- * Return the new addres, where the asm trampoline will jump to
- * after re-setting up the orig args
- */
- return (unsigned long) new_addr;
- }
- static int
- _dl_do_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
- ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
- {
- int reloc_type;
- int symtab_index;
- char *symname;
- unsigned long *reloc_addr;
- unsigned long symbol_addr;
- #if defined __SUPPORT_LD_DEBUG__
- unsigned long old_val = 0;
- #endif
- struct symbol_ref sym_ref;
- struct elf_resolve *tls_tpnt = NULL;
- reloc_addr = (unsigned long *)(tpnt->loadaddr + rpnt->r_offset);
- reloc_type = ELF_R_TYPE(rpnt->r_info);
- symtab_index = ELF_R_SYM(rpnt->r_info);
- symbol_addr = 0;
- sym_ref.sym = &symtab[symtab_index];
- sym_ref.tpnt = NULL;
- #if defined __SUPPORT_LD_DEBUG__
- if (reloc_addr)
- old_val = *reloc_addr;
- #endif
- if (symtab_index) {
- symname = strtab + symtab[symtab_index].st_name;
- symbol_addr = (unsigned long) _dl_find_hash(symname, scope, tpnt,
- elf_machine_type_class(reloc_type), &sym_ref);
- /*
- * We want to allow undefined references to weak symbols,
- * this might have been intentional. We should not be linking
- * local symbols here, so all bases should be covered.
- */
- if (unlikely(!symbol_addr
- && ELF_ST_BIND(symtab[symtab_index].st_info) != STB_WEAK
- && ELF_ST_TYPE(symtab[symtab_index].st_info) != STT_TLS)) {
- /* Non-fatal if called from dlopen, hence different ret code */
- return 1;
- }
- tls_tpnt = sym_ref.tpnt;
- } else if (reloc_type == R_ARC_RELATIVE ) {
- *reloc_addr += tpnt->loadaddr;
- goto log_entry;
- }
- #if defined USE_TLS && USE_TLS
- /* In case of a TLS reloc, tls_tpnt NULL means we have an 'anonymous'
- symbol. This is the case for a static tls variable, so the lookup
- module is just that one is referencing the tls variable. */
- if (!tls_tpnt)
- tls_tpnt = tpnt;
- #endif
- switch (reloc_type) {
- case R_ARC_NONE:
- break;
- case R_ARC_32:
- *reloc_addr += symbol_addr + rpnt->r_addend;
- break;
- case R_ARC_PC32:
- *reloc_addr += symbol_addr + rpnt->r_addend - (unsigned long) reloc_addr;
- break;
- case R_ARC_GLOB_DAT:
- case R_ARC_JMP_SLOT:
- *reloc_addr = symbol_addr;
- break;
- case R_ARC_COPY:
- _dl_memcpy((void *) reloc_addr,(void *) symbol_addr,
- symtab[symtab_index].st_size);
- break;
- #if defined USE_TLS && USE_TLS
- case R_ARC_TLS_DTPMOD:
- *reloc_addr = tls_tpnt->l_tls_modid;
- break;
- case R_ARC_TLS_DTPOFF:
- *reloc_addr = symbol_addr;
- break;
- case R_ARC_TLS_TPOFF:
- CHECK_STATIC_TLS ((struct link_map *) tls_tpnt);
- *reloc_addr = tls_tpnt->l_tls_offset + symbol_addr + rpnt->r_addend;
- break;
- #endif
- default:
- return -1;
- }
- log_entry:
- #if defined __SUPPORT_LD_DEBUG__
- if (_dl_debug_detail)
- _dl_dprintf(_dl_debug_file,"\tpatched: %x ==> %x @ %x",
- old_val, *reloc_addr, reloc_addr);
- #endif
- return 0;
- }
- static int
- _dl_do_lazy_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
- ELF_RELOC *rpnt)
- {
- int reloc_type;
- unsigned long *reloc_addr;
- #if defined __SUPPORT_LD_DEBUG__
- unsigned long old_val;
- #endif
- reloc_addr = (unsigned long *)(tpnt->loadaddr + rpnt->r_offset);
- reloc_type = ELF_R_TYPE(rpnt->r_info);
- #if defined __SUPPORT_LD_DEBUG__
- old_val = *reloc_addr;
- #endif
- switch (reloc_type) {
- case R_ARC_NONE:
- break;
- case R_ARC_JMP_SLOT:
- *reloc_addr += tpnt->loadaddr;
- break;
- default:
- return -1;
- }
- #if defined __SUPPORT_LD_DEBUG__
- if (_dl_debug_reloc && _dl_debug_detail)
- _dl_dprintf(_dl_debug_file, "\tpatched: %x ==> %x @ %x\n",
- old_val, *reloc_addr, reloc_addr);
- #endif
- return 0;
- }
- #define ___DO_LAZY 1
- #define ___DO_NOW 2
- static int _dl_parse(struct elf_resolve *tpnt, struct r_scope_elem *scope,
- unsigned long rel_addr, unsigned long rel_size, int type)
- {
- unsigned int i;
- char *strtab;
- ElfW(Sym) *symtab;
- ELF_RELOC *rpnt;
- int symtab_index;
- int res = 0;
- /* Now parse the relocation information */
- rpnt = (ELF_RELOC *)(intptr_t) (rel_addr);
- rel_size = rel_size / sizeof(ELF_RELOC);
- symtab = (ElfW(Sym) *)(intptr_t) (tpnt->dynamic_info[DT_SYMTAB]);
- strtab = (char *) (tpnt->dynamic_info[DT_STRTAB]);
- for (i = 0; i < rel_size; i++, rpnt++) {
- symtab_index = ELF_R_SYM(rpnt->r_info);
- debug_sym(symtab,strtab,symtab_index);
- debug_reloc(symtab,strtab,rpnt);
- /* constant propagation subsumes the 'if' */
- if (type == ___DO_LAZY)
- res = _dl_do_lazy_reloc(tpnt, scope, rpnt);
- else
- res = _dl_do_reloc(tpnt, scope, rpnt, symtab, strtab);
- if (res != 0)
- break;
- }
- if (unlikely(res != 0)) {
- if (res < 0) {
- int reloc_type = ELF_R_TYPE(rpnt->r_info);
- _dl_dprintf(2, "can't handle reloc type %x\n",
- reloc_type);
- _dl_exit(-res);
- } else {
- _dl_dprintf(2, "can't resolve symbol\n");
- /* Fall thru to return res */
- }
- }
- return res;
- }
- void
- _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
- unsigned long rel_addr,
- unsigned long rel_size)
- {
- /* This func is called for processing .rela.plt of loaded module(s)
- * The relo entries handled are JMP_SLOT type for fixing up .got slots
- * for external function calls.
- * This function doesn't resolve the slots: that is done lazily at
- * runtime. The build linker (at least thats what happens for ARC) had
- * pre-init the .got slots to point to PLT0. All that is done here is
- * to fix them up to point to load value of PLT0 (as opposed to the
- * build value).
- * On ARC, the loadaddr of dyn exec is zero, thus elfaddr == loadaddr
- * Thus there is no point in adding "0" to values and un-necessarily
- * stir up the caches and TLB.
- * For ldso processing busybox binary, this skips over 380 relo entries
- */
- if (rpnt->dyn->loadaddr != 0)
- _dl_parse(rpnt->dyn, NULL, rel_addr, rel_size, ___DO_LAZY);
- }
- int
- _dl_parse_relocation_information(struct dyn_elf *rpnt,
- struct r_scope_elem *scope,
- unsigned long rel_addr,
- unsigned long rel_size)
- {
- return _dl_parse(rpnt->dyn, scope, rel_addr, rel_size, ___DO_NOW);
- }
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