From patchwork Wed Jan 8 14:58:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathieu Desnoyers X-Patchwork-Id: 37249 Received: (qmail 13307 invoked by alias); 8 Jan 2020 14:59:23 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 13291 invoked by uid 89); 8 Jan 2020 14:59:23 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-24.8 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, KAM_STOCKGEN, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.1 spammy=4676, rel X-HELO: mail.efficios.com DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 43AB269599A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1578495559; bh=KriLFb1DyzRLx97UpRWTMCmtK6Fg4zvEJaeE7ye+unQ=; h=From:To:Date:Message-Id; b=T2zap+hedlHt9g2ETHrkAzJvr2t4DX4mW2QAX4PGCUjbDCAPGGal5q2lhI4LhOwYg FeEa4AJ9LuLREp+RgTUkac1U5d1QF+jjmVhuMzyr7uA7SthXuTzsacsLoMU1fdBPUn R1J7GS5tpWbWwcx9pY3tskVatuK1o0ewypm8m34fX7ghaH0qmjL/aF6fvqTKAa0R/a SviWD3dRDeBIs6QTDP5gxxdlFFCfGfYVCznrID/OSPjn8Qtz3y2BeXGr6Z9XHyPyzH F+xhYobYrL7ayZKwg3lXYFHr6wlPog8WnhXrlAU31lFttSnO6Eyw4JPtCrwMkvsy8u S4uFWImwUTYug== From: Mathieu Desnoyers To: Carlos O'Donell Cc: Florian Weimer , Joseph Myers , Szabolcs Nagy , libc-alpha@sourceware.org Subject: [RFC PATCH glibc 1/8] Introduce Date: Wed, 8 Jan 2020 09:58:44 -0500 Message-Id: <20200108145851.13594-2-mathieu.desnoyers@efficios.com> In-Reply-To: <20200108145851.13594-1-mathieu.desnoyers@efficios.com> References: <20200108145851.13594-1-mathieu.desnoyers@efficios.com> From: Florian Weimer 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). Built with build-many-glibcs.py, with manual verification that sysdeps/mips/elf_machine_sym_no_match.h is picked up on MIPS. Tested on aarch64-linux-gnu, i686-linux-gnu, powerpc64-linux-gnu, s390x-linux-gnu, x86_64-linux-gnu. * elf/elf_machine_sym_no_match.h: New file. * elf/dl-lookip.c (ELF_MACHINE_SYM_NO_MATCH): Do not define. * elf/dl-lookup.c (check_match) Call elf_machine_sym_no_match instead of ELF_MACHINE_SYM_NO_MATCH. * sysdeps/mips/dl-machine.h (ELF_MACHINE_SYM_NO_MATCH): Remove definition. * sysdeps/mips/elf_machine_sym_no_match.h: New file. Extracted from sysdeps/mips/dl-machine.h. --- elf/dl-lookup.c | 10 ++---- elf/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(-) create mode 100644 elf/elf_machine_sym_no_match.h create mode 100644 sysdeps/mips/elf_machine_sym_no_match.h diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index 378f28fa7d..db9785ab75 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/elf/elf_machine_sym_no_match.h b/elf/elf_machine_sym_no_match.h new file mode 100644 index 0000000000..6e299e5ee8 --- /dev/null +++ b/elf/elf_machine_sym_no_match.h @@ -0,0 +1,34 @@ +/* Function to ignore certain symbol matches for machine-specific reasons. + Copyright (C) 2019 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..f2be74caaf --- /dev/null +++ b/sysdeps/mips/elf_machine_sym_no_match.h @@ -0,0 +1,43 @@ +/* MIPS-specific handling of undefined symbols. + Copyright (C) 2008-2019 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 */