From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2178) id 8095C389367C; Fri, 24 Apr 2020 20:13:28 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 8095C389367C Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Florian Weimer To: glibc-cvs@sourceware.org Subject: [glibc] elf: Introduce X-Act-Checkin: glibc X-Git-Author: Florian Weimer X-Git-Refname: refs/heads/master X-Git-Oldrev: 781dacc4f41332098e3a272514b20a490a7ebc8c X-Git-Newrev: 50a2d83c08a94a10f88a1fedeb7a6e3667a6b732 Message-Id: <20200424201328.8095C389367C@sourceware.org> Date: Fri, 24 Apr 2020 20:13:28 +0000 (GMT) X-BeenThere: glibc-cvs@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Glibc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Apr 2020 20:13:28 -0000 https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=50a2d83c08a94a10f88a1fedeb7a6e3667a6b732 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: --- elf/dl-lookup.c | 10 ++----- sysdeps/generic/elf_machine_sym_no_match.h | 34 +++++++++++++++++++++++ sysdeps/mips/dl-machine.h | 15 ----------- sysdeps/mips/elf_machine_sym_no_match.h | 43 ++++++++++++++++++++++++++++++ 4 files changed, 79 insertions(+), 23 deletions(-) diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index 12a229f06c..807f3ea9b6 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 0000000000..27155de4c0 --- /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 06021ea9ab..e3b11a4f21 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 0000000000..9d09e5fa2d --- /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 */