From 8dbb7a08ec52057819db4ee234f9429ab99eb4ae Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Wed, 27 May 2020 12:54:21 -0700 Subject: dl-runtime: reloc_{offset,index} now functions arch overide'able The existing macros are fragile and expect local variables with a certain name. Fix this by defining them as functions with default implementation in a new header dl-runtime.h which arches can override if need be. This came up during ARC port review, hence the need for argument pltgot in reloc_index() which is not needed by existing ports. This patch potentially only affects hppa/x86 ports, build tested for both those configs and a few more. Reviewed-by: Adhemerval Zanella --- elf/dl-runtime.c | 28 +++++++++++++++++----------- elf/dl-runtime.h | 30 ++++++++++++++++++++++++++++++ 2 files changed, 47 insertions(+), 11 deletions(-) create mode 100644 elf/dl-runtime.h (limited to 'elf') diff --git a/elf/dl-runtime.c b/elf/dl-runtime.c index cf5f1d3e82..85a229f6f0 100644 --- a/elf/dl-runtime.c +++ b/elf/dl-runtime.c @@ -27,6 +27,7 @@ #include "dynamic-link.h" #include #include +#include #if (!ELF_MACHINE_NO_RELA && !defined ELF_MACHINE_PLT_REL) \ @@ -42,13 +43,6 @@ # define ARCH_FIXUP_ATTRIBUTE #endif -#ifndef reloc_offset -# define reloc_offset reloc_arg -# define reloc_index reloc_arg / sizeof (PLTREL) -#endif - - - /* This function is called through a special trampoline from the PLT the first time each PLT entry is called. We must perform the relocation specified in the PLT of the given shared object, and return the resolved @@ -68,8 +62,11 @@ _dl_fixup ( = (const void *) D_PTR (l, l_info[DT_SYMTAB]); const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]); + const uintptr_t pltgot = (uintptr_t) D_PTR (l, l_info[DT_PLTGOT]); + const PLTREL *const reloc - = (const void *) (D_PTR (l, l_info[DT_JMPREL]) + reloc_offset); + = (const void *) (D_PTR (l, l_info[DT_JMPREL]) + + reloc_offset (pltgot, reloc_arg)); const ElfW(Sym) *sym = &symtab[ELFW(R_SYM) (reloc->r_info)]; const ElfW(Sym) *refsym = sym; void *const rel_addr = (void *)(l->l_addr + reloc->r_offset); @@ -180,9 +177,12 @@ _dl_profile_fixup ( l, reloc_arg); } + const uintptr_t pltgot = (uintptr_t) D_PTR (l, l_info[DT_PLTGOT]); + /* This is the address in the array where we store the result of previous relocations. */ - struct reloc_result *reloc_result = &l->l_reloc_result[reloc_index]; + struct reloc_result *reloc_result + = &l->l_reloc_result[reloc_index (pltgot, reloc_arg, sizeof (PLTREL))]; /* CONCURRENCY NOTES: @@ -219,8 +219,11 @@ _dl_profile_fixup ( = (const void *) D_PTR (l, l_info[DT_SYMTAB]); const char *strtab = (const char *) D_PTR (l, l_info[DT_STRTAB]); + const uintptr_t pltgot = (uintptr_t) D_PTR (l, l_info[DT_PLTGOT]); + const PLTREL *const reloc - = (const void *) (D_PTR (l, l_info[DT_JMPREL]) + reloc_offset); + = (const void *) (D_PTR (l, l_info[DT_JMPREL]) + + reloc_offset (pltgot, reloc_arg)); const ElfW(Sym) *refsym = &symtab[ELFW(R_SYM) (reloc->r_info)]; const ElfW(Sym) *defsym = refsym; lookup_t result; @@ -485,11 +488,14 @@ _dl_call_pltexit (struct link_map *l, ElfW(Word) reloc_arg, const void *inregs, void *outregs) { #ifdef SHARED + const uintptr_t pltgot = (uintptr_t) D_PTR (l, l_info[DT_PLTGOT]); + /* This is the address in the array where we store the result of previous relocations. */ // XXX Maybe the bound information must be stored on the stack since // XXX with bind_not a new value could have been stored in the meantime. - struct reloc_result *reloc_result = &l->l_reloc_result[reloc_index]; + struct reloc_result *reloc_result = + &l->l_reloc_result[reloc_index (pltgot, reloc_arg, sizeof (PLTREL))]; ElfW(Sym) *defsym = ((ElfW(Sym) *) D_PTR (reloc_result->bound, l_info[DT_SYMTAB]) + reloc_result->boundndx); diff --git a/elf/dl-runtime.h b/elf/dl-runtime.h new file mode 100644 index 0000000000..78f1da77fb --- /dev/null +++ b/elf/dl-runtime.h @@ -0,0 +1,30 @@ +/* Helpers for On-demand PLT fixup for shared objects. Generic version. + Copyright (C) 2020 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +static inline uintptr_t +reloc_offset (uintptr_t plt0, uintptr_t pltn) +{ + return pltn; +} + +static inline uintptr_t +reloc_index (uintptr_t plt0, uintptr_t pltn, size_t size) +{ + return pltn / size; +} -- cgit 1.4.1