From patchwork Tue Aug 14 10:06:38 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 28888 Received: (qmail 104220 invoked by alias); 14 Aug 2018 10:06:46 -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 104208 invoked by uid 89); 14 Aug 2018 10:06:45 -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, SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=registration, csu, ports X-HELO: mx1.redhat.com Subject: Re: [PATCH] Introduce ELF_INITFINI for all architectures To: Adhemerval Zanella , libc-alpha@sourceware.org References: <20180623214521.290CE402DFEF9@oldenburg.str.redhat.com> <7e88376d-17ee-2015-4b9a-6cf788971f15@redhat.com> <18c3b430-2cbe-f410-d2c5-f54647a1e5eb@linaro.org> From: Florian Weimer Message-ID: <5ffaedea-0efb-1800-744b-583fb2faf1c2@redhat.com> Date: Tue, 14 Aug 2018 12:06:38 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <18c3b430-2cbe-f410-d2c5-f54647a1e5eb@linaro.org> On 08/08/2018 10:42 PM, Adhemerval Zanella wrote: >> + bool have_init = ELF_INITFINI && l->l_info[DT_INIT] != NULL; >> + >> /* Are there any constructors? */ >> - if (l->l_info[DT_INIT] == NULL >> - && __builtin_expect (l->l_info[DT_INIT_ARRAY] == NULL, 1)) >> + if (!have_init && __builtin_expect (l->l_info[DT_INIT_ARRAY] == NULL, 1)) >> return; > > Maybe __glibc_likely. Both INIT and INIT_ARRAY are extremely common, perhaps due to the TM registration code in GCC. I've dropped the early return in the attached patch. >> +/* This file contains definitions specifying behavior of a platform >> + (CPU + kernel) combination. It must be usable from both assembler >> + sources and C sources. Definitions should be namespace-clean. */ >> + > > Shouldn't we note ABI take in consideration as well? Sorry, ABI in what sense? >> +#ifndef _PLATFORM_PARAMS_H >> +#define _PLATFORM_PARAMS_H >> + >> +/* Most platforms use _init/_fini symbols to call constructors and >> + destructors. If defined to 0, the dynamic loader will ignore >> + DT_INIT and DT_FINI tags, and static binaries will not call the >> + _init or _fini functions. */ >> +#define ELF_INITFINI 1 > > I assume for new ABIs init_array is the prefered and the expected way to > initialize constructors. Should we add a comment that new ports are > expected set it as 0? I'm not sure if that's happening with new ports. Thanks, Florian Subject: [PATCH] Introduce ELF_INITFINI for all architectures To: libc-alpha@sourceware.org This supersedes the init_array sysdeps directory. It allows us to check for ELF_INITFINI in both C and assembler code, and skip DT_INIT and DT_FINI processing completely on RISC-V. A new header file is needed because is incompatible with assembler code. is compatible with assembler code, but it cannot be included in all assembler files because on some architectures, it redefines register names, and some assembler files conflict with that. 2018-08-14 Florian Weimer Introduce ELF_INITFINI, set everywhere except on RISC-V. * sysdeps/init_array/crti.S: Move to ... * sysdepes/generic/crti.S: here. Report an error if ELF_INITFINI. * sysdeps/init_array/crtn.S: Move to ... * sysdeps/generic/crtn.S: here. Report an error if ELF_INITFINI. * csu/elf-init.c: Check ELF_INITFINI instead of NO_INITFINI. * gmon/gmon-start.c [!ELF_INITFINI] (GMON_START_ARRAY_SECTION): Define. * elf/dl-fini.c (_dl_fini): Check for ELF_INITFINI before using DT_FINI. * elf/dl-init.c (call_init): Drop early return because most binaries have DT_INIT and DT_INITARRAY. Check for ELF_INITFINI before using DT_INIT. * nptl/pt-crti.S [ELF_INITFINI]: Use .init_array instead of PREINIT_FUNCTION. * sysdeps/generic/platform-params.h: New file. * sysdeps/init_array/elf-init.c: Remove file. * sysdeps/init_array/gmon-start.c: Likewise. * sysdeps/init_array/pt-crti.S: Likewise. * sysdeps/riscv/Implies (init_array): Remove. * sysdeps/riscv/platform-params.h: New file. diff --git a/csu/elf-init.c b/csu/elf-init.c index da59b2c77b..8bde25a340 100644 --- a/csu/elf-init.c +++ b/csu/elf-init.c @@ -34,6 +34,7 @@ . */ #include +#include /* These magic symbols are provided by the linker. */ @@ -49,7 +50,7 @@ extern void (*__fini_array_start []) (void) attribute_hidden; extern void (*__fini_array_end []) (void) attribute_hidden; -#ifndef NO_INITFINI +#if ELF_INITFINI /* These function symbols are provided for the .init/.fini section entry points automagically by the linker. */ extern void _init (void); @@ -79,7 +80,7 @@ __libc_csu_init (int argc, char **argv, char **envp) } #endif -#ifndef NO_INITFINI +#if ELF_INITFINI _init (); #endif @@ -99,7 +100,7 @@ __libc_csu_fini (void) while (i-- > 0) (*__fini_array_start [i]) (); -# ifndef NO_INITFINI +# if ELF_INITFINI _fini (); # endif #endif diff --git a/csu/gmon-start.c b/csu/gmon-start.c index 6a130890a9..f9fbdbfed8 100644 --- a/csu/gmon-start.c +++ b/csu/gmon-start.c @@ -37,6 +37,7 @@ #include #include #include +#include #define __ASSEMBLY__ #include @@ -59,6 +60,13 @@ extern char etext[]; # endif #endif +#if !ELF_INITFINI +/* Instead of defining __gmon_start__ globally in gcrt1.o, we make it + static and just put a pointer to it into the .preinit_array + section. */ +# define GMON_START_ARRAY_SECTION ".preinit_array" +#endif + #ifdef GMON_START_ARRAY_SECTION static void __gmon_start__ (void); static void (*const gmon_start_initializer) (void) diff --git a/elf/dl-fini.c b/elf/dl-fini.c index 3cfc262400..20c5581525 100644 --- a/elf/dl-fini.c +++ b/elf/dl-fini.c @@ -19,6 +19,7 @@ #include #include #include +#include /* Type of the constructor functions. */ @@ -117,7 +118,7 @@ _dl_fini (void) /* Is there a destructor function? */ if (l->l_info[DT_FINI_ARRAY] != NULL - || l->l_info[DT_FINI] != NULL) + || (ELF_INITFINI && l->l_info[DT_FINI] != NULL)) { /* When debugging print a message first. */ if (__builtin_expect (GLRO(dl_debug_mask) @@ -139,7 +140,7 @@ _dl_fini (void) } /* Next try the old-style destructor. */ - if (l->l_info[DT_FINI] != NULL) + if (ELF_INITFINI && l->l_info[DT_FINI] != NULL) DL_CALL_DT_FINI (l, l->l_addr + l->l_info[DT_FINI]->d_un.d_ptr); } diff --git a/elf/dl-init.c b/elf/dl-init.c index 3e72fa3013..690ba6dd41 100644 --- a/elf/dl-init.c +++ b/elf/dl-init.c @@ -18,6 +18,7 @@ #include #include +#include /* Type of the initializer. */ @@ -40,11 +41,6 @@ call_init (struct link_map *l, int argc, char **argv, char **env) && l->l_type == lt_executable) return; - /* Are there any constructors? */ - if (l->l_info[DT_INIT] == NULL - && __builtin_expect (l->l_info[DT_INIT_ARRAY] == NULL, 1)) - return; - /* Print a debug message if wanted. */ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS)) _dl_debug_printf ("\ncalling init: %s\n\n", @@ -54,7 +50,7 @@ call_init (struct link_map *l, int argc, char **argv, char **env) - the one named by DT_INIT - the others in the DT_INIT_ARRAY. */ - if (l->l_info[DT_INIT] != NULL) + if (ELF_INITFINI && l->l_info[DT_INIT] != NULL) DL_CALL_DT_INIT(l, l->l_addr + l->l_info[DT_INIT]->d_un.d_ptr, argc, argv, env); /* Next see whether there is an array with initialization functions. */ diff --git a/nptl/pt-crti.S b/nptl/pt-crti.S index a0deb9979c..efd28c8f7e 100644 --- a/nptl/pt-crti.S +++ b/nptl/pt-crti.S @@ -33,11 +33,18 @@ License along with the GNU C Library; if not, see . */ +#include + /* Arrange for __pthread_initialize_minimal_internal to be called at libpthread startup, instead of conditionally calling __gmon_start__. */ -#define PREINIT_FUNCTION __pthread_initialize_minimal_internal -#define PREINIT_FUNCTION_WEAK 0 +#if ELF_INITFINI +# define PREINIT_FUNCTION __pthread_initialize_minimal_internal +# define PREINIT_FUNCTION_WEAK 0 -#include +# include +#else + .section .init_array,"a",%init_array + .dc.a __pthread_initialize_minimal_internal +#endif diff --git a/sysdeps/init_array/crti.S b/sysdeps/generic/crti.S similarity index 80% rename from sysdeps/init_array/crti.S rename to sysdeps/generic/crti.S index 145c918f93..1a86132b88 100644 --- a/sysdeps/init_array/crti.S +++ b/sysdeps/generic/crti.S @@ -12,11 +12,17 @@ toolchains without .init_array support can use this to avoid the superfluous .init and .fini boilerplate code. */ +#include + +#if ELF_INITFINI +# error Cannot use default crti.S because it lacks _init code +#endif + #ifdef PREINIT_FUNCTION -#if PREINIT_FUNCTION_WEAK -# error PREINIT_FUNCTION_WEAK is unsupported -#endif +# if PREINIT_FUNCTION_WEAK +# error PREINIT_FUNCTION_WEAK is unsupported +# endif /* This arranges for PREINIT_FUNCTION to be called upon loading a library that contains crti.o. */ diff --git a/sysdeps/init_array/crtn.S b/sysdeps/generic/crtn.S similarity index 82% rename from sysdeps/init_array/crtn.S rename to sysdeps/generic/crtn.S index 6f70e77160..6996e0001d 100644 --- a/sysdeps/init_array/crtn.S +++ b/sysdeps/generic/crtn.S @@ -11,3 +11,9 @@ But new configurations without compatibility concerns for toolchains without .init_array support can use this to avoid the superfluous .init and .fini boilerplate code. */ + +#include + +#if ELF_INITFINI +# error Cannot use genetric crtn.S because it lacks _fini code +#endif diff --git a/sysdeps/generic/platform-params.h b/sysdeps/generic/platform-params.h new file mode 100644 index 0000000000..5a732fa02f --- /dev/null +++ b/sysdeps/generic/platform-params.h @@ -0,0 +1,32 @@ +/* Various definitions for specifying platform behavior. Generic version. + Copyright (C) 2018 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 + . */ + +/* This file contains definitions specifying behavior of a platform + (CPU + kernel) combination. It must be usable from both assembler + sources and C sources. Definitions should be namespace-clean. */ + +#ifndef _PLATFORM_PARAMS_H +#define _PLATFORM_PARAMS_H + +/* Most platforms use _init/_fini symbols to call constructors and + destructors. If defined to 0, the dynamic loader will ignore + DT_INIT and DT_FINI tags, and static binaries will not call the + _init or _fini functions. */ +#define ELF_INITFINI 1 + +#endif /* _PLATFORM_PARAMS_H */ diff --git a/sysdeps/init_array/elf-init.c b/sysdeps/init_array/elf-init.c deleted file mode 100644 index 9fbe82e93c..0000000000 --- a/sysdeps/init_array/elf-init.c +++ /dev/null @@ -1,37 +0,0 @@ -/* Startup support for ELF initializers/finalizers in the main executable. - Copyright (C) 2013-2018 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. - - In addition to the permissions in the GNU Lesser General Public - License, the Free Software Foundation gives you unlimited - permission to link the compiled version of this file with other - programs, and to distribute those programs without any restriction - coming from the use of this file. (The GNU Lesser General Public - License restrictions do apply in other respects; for example, they - cover modification of the file, and distribution when not linked - into another program.) - - Note that people who make modified versions of this file are not - obligated to grant this special exception for their modified - versions; it is their choice whether to do so. The GNU Lesser - General Public License gives permission to release a modified - version without this exception; this exception also makes it - possible to release a modified version which carries forward this - exception. - - 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 - . */ - -#define NO_INITFINI -#include diff --git a/sysdeps/init_array/gmon-start.c b/sysdeps/init_array/gmon-start.c deleted file mode 100644 index 3bacaf7e38..0000000000 --- a/sysdeps/init_array/gmon-start.c +++ /dev/null @@ -1,41 +0,0 @@ -/* gmon startup hook using .preinit_array. - Copyright (C) 2013-2018 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. - - In addition to the permissions in the GNU Lesser General Public - License, the Free Software Foundation gives you unlimited - permission to link the compiled version of this file with other - programs, and to distribute those programs without any restriction - coming from the use of this file. (The GNU Lesser General Public - License restrictions do apply in other respects; for example, they - cover modification of the file, and distribution when not linked - into another program.) - - Note that people who make modified versions of this file are not - obligated to grant this special exception for their modified - versions; it is their choice whether to do so. The GNU Lesser - General Public License gives permission to release a modified - version without this exception; this exception also makes it - possible to release a modified version which carries forward this - exception. - - 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 - . */ - -/* Instead of defining __gmon_start__ globally in gcrt1.o, we make it - static and just put a pointer to it into the .preinit_array section. */ - -#define GMON_START_ARRAY_SECTION ".preinit_array" - -#include diff --git a/sysdeps/riscv/Implies b/sysdeps/riscv/Implies index c88325b8be..1945b1f4bb 100644 --- a/sysdeps/riscv/Implies +++ b/sysdeps/riscv/Implies @@ -1,5 +1,3 @@ -init_array - ieee754/ldbl-128 ieee754/dbl-64 ieee754/flt-32 diff --git a/sysdeps/init_array/pt-crti.S b/sysdeps/riscv/platform-params.h similarity index 70% rename from sysdeps/init_array/pt-crti.S rename to sysdeps/riscv/platform-params.h index 9bf17059dd..b71591437d 100644 --- a/sysdeps/init_array/pt-crti.S +++ b/sysdeps/riscv/platform-params.h @@ -1,5 +1,5 @@ -/* Special initializer support for libpthread. - Copyright (C) 2015-2018 Free Software Foundation, Inc. +/* Various definitions for specifying platform behavior. RISC_V version. + Copyright (C) 2018 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 @@ -16,8 +16,10 @@ License along with the GNU C Library; if not, see . */ -/* This arranges for libpthread.so's special initializer to be called as - soon as the library is loaded. */ +#ifndef _PLATFORM_PARAMS_H +#define _PLATFORM_PARAMS_H - .section .init_array,"a",%init_array - .dc.a __pthread_initialize_minimal_internal +/* RISC-V does not have .init/.fini. */ +#define ELF_INITFINI 0 + +#endif /* _PLATFORM_PARAMS_H */