Resolve the GOT before doing relocations. Then, when doing relocations, for
symbols in the global part of the symbol table, use the updated GOT entry
rather than doing a lookup. (This provides the same effect as `-z combreloc'
on other platforms -- at most one lookup is done per symbol.)
Unfortunately, it is necessary to turn off lazy binding on MIPS. As the
comment says:
* 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, but GNU ld does not do so reliably.
This commit is contained in:
mycroft
parent
7798fe3a64
commit
a3c903f7cb
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@ -1,4 +1,4 @@
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/* $NetBSD: mips_reloc.c,v 1.33 2002/09/14 23:53:21 thorpej Exp $ */
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/* $NetBSD: mips_reloc.c,v 1.34 2002/09/25 03:52:06 mycroft Exp $ */
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/*
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/*
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* Copyright 1997 Michael L. Hitch <mhitch@montana.edu>
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* Copyright 1997 Michael L. Hitch <mhitch@montana.edu>
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@ -108,27 +108,6 @@ _rtld_relocate_nonplt_self(dynp, relocbase)
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break;
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break;
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}
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}
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}
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}
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rellim = (const Elf_Rel *)((caddr_t)rel + relsz);
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for (; rel < rellim; rel++) {
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where = (Elf_Addr *)(relocbase + rel->r_offset);
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switch (ELF_R_TYPE(rel->r_info)) {
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case R_TYPE(NONE):
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break;
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case R_TYPE(REL32):
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sym = symtab + ELF_R_SYM(rel->r_info);
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if (ELF_ST_BIND(sym->st_info) == STB_LOCAL &&
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ELF_ST_TYPE(sym->st_info) == STT_SECTION)
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*where += (Elf_Addr)(sym->st_value + relocbase);
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else
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abort();
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break;
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default:
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abort();
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}
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}
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i = (got[1] & 0x80000000) ? 2 : 1;
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i = (got[1] & 0x80000000) ? 2 : 1;
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/* Relocate the local GOT entries */
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/* Relocate the local GOT entries */
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@ -142,6 +121,26 @@ _rtld_relocate_nonplt_self(dynp, relocbase)
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++sym;
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++sym;
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++got;
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++got;
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}
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}
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rellim = (const Elf_Rel *)((caddr_t)rel + relsz);
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for (; rel < rellim; rel++) {
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where = (Elf_Addr *)(relocbase + rel->r_offset);
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switch (ELF_R_TYPE(rel->r_info)) {
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case R_TYPE(NONE):
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break;
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case R_TYPE(REL32):
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assert(ELF_R_SYM(rel->r_info) < gotsym);
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sym = symtab + ELF_R_SYM(rel->r_info);
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assert(sym->st_info == STT_SECTION);
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*where += (Elf_Addr)(sym->st_value + relocbase);
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break;
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default:
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abort();
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}
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}
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}
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}
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/*
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/*
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@ -182,6 +181,60 @@ _rtld_relocate_nonplt_objects(obj, self)
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if (self)
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if (self)
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return 0;
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return 0;
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i = (got[1] & 0x80000000) ? 2 : 1;
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/* Relocate the local GOT entries */
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got += i;
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for (; i < obj->local_gotno; i++)
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*got++ += (Elf_Addr)obj->relocbase;
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sym = obj->symtab + obj->gotsym;
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/* Now do the global GOT entries */
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for (i = obj->gotsym; i < obj->symtabno; i++) {
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rdbg((" doing got %d sym %p (%s, %x)", i - obj->gotsym, sym,
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sym->st_name + obj->strtab, *got));
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if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
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sym->st_shndx == SHN_UNDEF) {
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/*
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* XXX DANGER WILL ROBINSON!
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* You might think this is stupid, as it intentionally
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* defeats lazy binding -- and you'd be right.
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* Unfortunately, for lazy binding to work right, we
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* need to a way to force the GOT slots used for
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* function pointers to be resolved immediately. This
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* is supposed to be done automatically by the linker,
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* by not outputting a PLT slot and setting st_value
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* to 0, but GNU ld does not do so reliably.
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*/
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def = _rtld_find_symdef(i, obj, &defobj, true);
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if (def == NULL)
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return -1;
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*got = def->st_value + (Elf_Addr)defobj->relocbase;
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} else if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
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sym->st_value != 0) {
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/*
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* If there are non-PLT references to the function,
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* st_value should be 0, forcing us to resolve the
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* address immediately.
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*/
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*got = sym->st_value + (Elf_Addr)obj->relocbase;
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} else if (sym->st_info == ELF_ST_INFO(STB_GLOBAL, STT_SECTION)) {
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/* Symbols with index SHN_ABS are not relocated. */
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if (sym->st_shndx != SHN_ABS)
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*got = sym->st_value +
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(Elf_Addr)obj->relocbase;
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} else {
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def = _rtld_find_symdef(i, obj, &defobj, true);
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if (def == NULL)
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return -1;
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*got = def->st_value + (Elf_Addr)defobj->relocbase;
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}
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rdbg((" --> now %x", *got));
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++sym;
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++got;
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}
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got = obj->pltgot;
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for (rel = obj->rel; rel < obj->rellim; rel++) {
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for (rel = obj->rel; rel < obj->rellim; rel++) {
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Elf_Addr *where, tmp;
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Elf_Addr *where, tmp;
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unsigned long symnum;
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unsigned long symnum;
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@ -197,9 +250,16 @@ _rtld_relocate_nonplt_objects(obj, self)
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/* 32-bit PC-relative reference */
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/* 32-bit PC-relative reference */
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def = obj->symtab + symnum;
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def = obj->symtab + symnum;
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if (ELF_ST_BIND(def->st_info) == STB_LOCAL &&
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if (symnum >= obj->gotsym) {
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(ELF_ST_TYPE(def->st_info) == STT_SECTION ||
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tmp = *where;
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ELF_ST_TYPE(def->st_info) == STT_NOTYPE)) {
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tmp += got[obj->local_gotno + symnum - obj->gotsym];
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*where = tmp;
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rdbg(("REL32/G %s in %s --> %p in %s",
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obj->strtab + def->st_name, obj->path,
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(void *)tmp, obj->path));
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break;
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} else {
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/*
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/*
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* XXX: ABI DIFFERENCE!
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* XXX: ABI DIFFERENCE!
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*
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*
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@ -220,48 +280,18 @@ _rtld_relocate_nonplt_objects(obj, self)
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*
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*
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* --rkb, Oct 6, 2001
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* --rkb, Oct 6, 2001
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*/
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*/
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if (__predict_true(RELOC_ALIGNED_P(where))) {
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tmp = *where;
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tmp = *where;
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if (def->st_info == STT_SECTION &&
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if (def->st_info == STT_SECTION &&
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tmp < def->st_value)
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tmp < def->st_value)
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tmp += (Elf_Addr)def->st_value;
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tmp += (Elf_Addr)def->st_value;
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tmp += (Elf_Addr)obj->relocbase;
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tmp += (Elf_Addr)obj->relocbase;
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*where = tmp;
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*where = tmp;
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} else {
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tmp = load_ptr(where);
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if (def->st_info == STT_SECTION &&
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tmp < def->st_value)
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tmp += (Elf_Addr)def->st_value;
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tmp += (Elf_Addr)obj->relocbase;
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store_ptr(where, tmp);
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}
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rdbg(("REL32 %s in %s --> %p in %s",
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rdbg(("REL32 %s in %s --> %p in %s",
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obj->strtab + def->st_name, obj->path,
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obj->strtab + def->st_name, obj->path,
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(void *)tmp, obj->path));
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(void *)tmp, obj->path));
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} else {
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def = _rtld_find_symdef(symnum, obj, &defobj,
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false);
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if (def == NULL)
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return -1;
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if (__predict_true(RELOC_ALIGNED_P(where))) {
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tmp = *where +
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(Elf_Addr)(defobj->relocbase +
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def->st_value);
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*where = tmp;
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} else {
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tmp = load_ptr(where) +
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(Elf_Addr)(defobj->relocbase +
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def->st_value);
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store_ptr(where, tmp);
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}
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rdbg(("REL32 %s in %s --> %p in %s",
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obj->strtab + obj->symtab[symnum].st_name,
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obj->path, (void *)tmp, defobj->path));
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}
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}
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break;
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break;
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@ -278,39 +308,6 @@ _rtld_relocate_nonplt_objects(obj, self)
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}
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}
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}
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}
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i = (got[1] & 0x80000000) ? 2 : 1;
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/* Relocate the local GOT entries */
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got += i;
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for (; i < obj->local_gotno; i++)
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*got++ += (Elf_Addr)obj->relocbase;
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sym = obj->symtab + obj->gotsym;
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/* Now do the global GOT entries */
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for (i = obj->gotsym; i < obj->symtabno; i++) {
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rdbg((" doing got %d sym %p (%s, %x)", i - obj->gotsym, sym,
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sym->st_name + obj->strtab, *got));
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if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
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sym->st_value != 0)
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/* The symbol table contains the address of the PLT
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slot. However, sometimes a PLT slot is not
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allocated, so we have to check st_value first. */
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*got = sym->st_value + (Elf_Addr)obj->relocbase;
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else if (ELF_ST_TYPE(sym->st_info) == STT_SECTION &&
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ELF_ST_BIND(sym->st_info) == STB_GLOBAL) {
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/* Symbols with index SHN_ABS are not relocated. */
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if (sym->st_shndx != SHN_ABS)
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*got = sym->st_value +
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(Elf_Addr)obj->relocbase;
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} else {
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def = _rtld_find_symdef(i, obj, &defobj, true);
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if (def == NULL)
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return -1;
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*got = def->st_value + (Elf_Addr)defobj->relocbase;
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}
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++sym;
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++got;
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}
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return 0;
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return 0;
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}
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}
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Loading…
Reference in New Issue