From patchwork Thu Mar 26 15:56:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathieu Desnoyers X-Patchwork-Id: 38622 Return-Path: X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail.efficios.com (mail.efficios.com [167.114.26.124]) by sourceware.org (Postfix) with ESMTPS id 1A80D385E009 for ; Thu, 26 Mar 2020 15:56:58 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 1A80D385E009 Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id BEC192777DC; Thu, 26 Mar 2020 11:56:57 -0400 (EDT) Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id UAvscK-pvJDP; Thu, 26 Mar 2020 11:56:57 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 40A572777D9; Thu, 26 Mar 2020 11:56:57 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 40A572777D9 X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id YtxQLU5iOnp1; Thu, 26 Mar 2020 11:56:57 -0400 (EDT) Received: from localhost.localdomain (192-222-181-218.qc.cable.ebox.net [192.222.181.218]) by mail.efficios.com (Postfix) with ESMTPSA id 0D96B2772C1; Thu, 26 Mar 2020 11:56:57 -0400 (EDT) From: Mathieu Desnoyers To: Carlos O'Donell Cc: Florian Weimer , Joseph Myers , Szabolcs Nagy , libc-alpha@sourceware.org Subject: [PATCH glibc 1/9] Introduce Date: Thu, 26 Mar 2020 11:56:25 -0400 Message-Id: <20200326155633.18236-2-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200326155633.18236-1-mathieu.desnoyers@efficios.com> References: <20200326155633.18236-1-mathieu.desnoyers@efficios.com> X-Spam-Status: No, score=-29.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, KAM_STOCKGEN, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Mar 2020 15:56:59 -0000 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/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 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/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 */