commit 50a2d83c08a94a10f88a1fedeb7a6e3667a6b732 Author: Florian Weimer Date: Fri Apr 24 22:13:03 2020 +0200 elf: Introduce MIPS needs to ignore certain existing symbols during symbol lookup. The old scheme uses the ELF_MACHINE_SYM_NO_MATCH macro, with an inline function, within its own header, with a sysdeps override for MIPS. This allows re-use of the function from another file (without having to include or providing the default definition for ELF_MACHINE_SYM_NO_MATCH). Reviewed-by: Carlos O'Donell diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index e4c479de9a1fd6ec..47acd134600b44b5 100644 --- a/elf/dl-lookup.c +++ b/elf/dl-lookup.c @@ -28,18 +28,12 @@ #include #include #include +#include #include -/* Return nonzero if check_match should consider SYM to fail to match a - symbol reference for some machine-specific reason. */ -#ifndef ELF_MACHINE_SYM_NO_MATCH -# define ELF_MACHINE_SYM_NO_MATCH(sym) 0 -#endif - #define VERSTAG(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (tag)) - struct sym_val { const ElfW(Sym) *s; @@ -78,7 +72,7 @@ check_match (const char *const undef_name, if (__glibc_unlikely ((sym->st_value == 0 /* No value. */ && sym->st_shndx != SHN_ABS && stt != STT_TLS) - || ELF_MACHINE_SYM_NO_MATCH (sym) + || elf_machine_sym_no_match (sym) || (type_class & (sym->st_shndx == SHN_UNDEF)))) return NULL; diff --git a/sysdeps/generic/elf_machine_sym_no_match.h b/sysdeps/generic/elf_machine_sym_no_match.h new file mode 100644 index 0000000000000000..27155de4c0358460 --- /dev/null +++ b/sysdeps/generic/elf_machine_sym_no_match.h @@ -0,0 +1,34 @@ +/* Function to ignore certain symbol matches for machine-specific reasons. + 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, see + . */ + +#ifndef _ELF_MACHINE_SYM_NO_MATCH_H +#define _ELF_MACHINE_SYM_NO_MATCH_H + +#include +#include + +/* This can be customized to ignore certain symbols during lookup in + case there are machine-specific rules to disregard some + symbols. */ +static inline bool +elf_machine_sym_no_match (const ElfW(Sym) *sym) +{ + return false; +} + +#endif /* _ELF_MACHINE_SYM_NO_MATCH_H */ diff --git a/sysdeps/mips/dl-machine.h b/sysdeps/mips/dl-machine.h index 91fc640388a735c7..b41e10647d81843b 100644 --- a/sysdeps/mips/dl-machine.h +++ b/sysdeps/mips/dl-machine.h @@ -467,21 +467,6 @@ elf_machine_plt_value (struct link_map *map, const ElfW(Rel) *reloc, return value; } -/* The semantics of zero/non-zero values of undefined symbols differs - depending on whether the non-PIC ABI is in use. Under the non-PIC - ABI, a non-zero value indicates that there is an address reference - to the symbol and thus it must always be resolved (except when - resolving a jump slot relocation) to the PLT entry whose address is - provided as the symbol's value; a zero value indicates that this - canonical-address behaviour is not required. Yet under the classic - MIPS psABI, a zero value indicates that there is an address - reference to the function and the dynamic linker must resolve the - symbol immediately upon loading. To avoid conflict, symbols for - which the dynamic linker must assume the non-PIC ABI semantics are - marked with the STO_MIPS_PLT flag. */ -#define ELF_MACHINE_SYM_NO_MATCH(sym) \ - ((sym)->st_shndx == SHN_UNDEF && !((sym)->st_other & STO_MIPS_PLT)) - #endif /* !dl_machine_h */ #ifdef RESOLVE_MAP diff --git a/sysdeps/mips/elf_machine_sym_no_match.h b/sysdeps/mips/elf_machine_sym_no_match.h new file mode 100644 index 0000000000000000..9d09e5fa2db1ff6c --- /dev/null +++ b/sysdeps/mips/elf_machine_sym_no_match.h @@ -0,0 +1,43 @@ +/* MIPS-specific handling of undefined symbols. + Copyright (C) 2008-2020 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, see + . */ + +#ifndef _ELF_MACHINE_SYM_NO_MATCH_H +#define _ELF_MACHINE_SYM_NO_MATCH_H + +#include +#include + +/* The semantics of zero/non-zero values of undefined symbols differs + depending on whether the non-PIC ABI is in use. Under the non-PIC + ABI, a non-zero value indicates that there is an address reference + to the symbol and thus it must always be resolved (except when + resolving a jump slot relocation) to the PLT entry whose address is + provided as the symbol's value; a zero value indicates that this + canonical-address behaviour is not required. Yet under the classic + MIPS psABI, a zero value indicates that there is an address + reference to the function and the dynamic linker must resolve the + symbol immediately upon loading. To avoid conflict, symbols for + which the dynamic linker must assume the non-PIC ABI semantics are + marked with the STO_MIPS_PLT flag. */ +static inline bool +elf_machine_sym_no_match (const ElfW(Sym) *sym) +{ + return sym->st_shndx == SHN_UNDEF && !(sym->st_other & STO_MIPS_PLT); +} + +#endif /* _ELF_MACHINE_SYM_NO_MATCH_H */