From patchwork Wed May 14 16:47:27 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roland McGrath X-Patchwork-Id: 348884 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 82BC914008B for ; Thu, 15 May 2014 02:47:36 +1000 (EST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:mime-version:content-type :content-transfer-encoding:from:to:cc:subject:in-reply-to :references:message-id:date; q=dns; s=default; b=I+zxhiJ/vTeu9q6 Sh4Iz7GO5EMyCOQTUVvM8iQ7Kk/p4iG1EPxMcZqCjusNG1jkMcd8VkTSPDeVEkwn gCHg/A8NE0IGpfVVLP/ofvT2mGuvawUop7gopZ4MwEi+AOMWErcw7aO1+jW7Czxa gZb1SNNNWiUVXzXJZXxoGbwnCfB8= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:mime-version:content-type :content-transfer-encoding:from:to:cc:subject:in-reply-to :references:message-id:date; s=default; bh=9NoBd60pfLdTUj15wmoV1 mvWzCI=; b=VIw+AdJly2tFZjAM0vHGWqZSpmFqT8YeZZjoOfTaWRyBRUgM6htrd fLfqB94xhJAz6s5yS+ydH7lS+49aQZQrPubkXNwyuG1IxaX23cL9ANANaPO2SeeP uC61KdWykbENG9+klxjW3M0ITjTRX6intEtyiUPJ86Aw6EIUYYK3LE= Received: (qmail 7433 invoked by alias); 14 May 2014 16:47:31 -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 7422 invoked by uid 89); 14 May 2014 16:47:30 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.3 required=5.0 tests=AWL, BAYES_00 autolearn=ham version=3.3.2 X-HELO: topped-with-meat.com MIME-Version: 1.0 From: Roland McGrath To: "Joseph S. Myers" Cc: "GNU C. Library" Subject: Re: [PATCH 1/2 roland/nptl] ARM: Consolidate NPTL/non versions of vfork In-Reply-To: Joseph S. Myers's message of Tuesday, 13 May 2014 23:01:05 +0000 References: <20140513221939.A63F52C39B4@topped-with-meat.com> Message-Id: <20140514164727.580952C39C7@topped-with-meat.com> Date: Wed, 14 May 2014 09:47:27 -0700 (PDT) X-CMAE-Score: 0 X-CMAE-Analysis: v=2.1 cv=HrjlRSjS c=1 sm=1 tr=0 a=WkljmVdYkabdwxfqvArNOQ==:117 a=14OXPxybAAAA:8 a=9YwlLrt9Z0oA:10 a=Z6MIti7PxpgA:10 a=kj9zAlcOel0A:10 a=hOe2yjtxAAAA:8 a=mDV3o1hIAAAA:8 a=DvBSG1bP4tg-ZFA9zt4A:9 a=LMjntV8SV0rlSl3k:21 a=l1RtwxwCUmU3TLf9:21 a=CjuIK1q_8ugA:10 > ARM supports IFUNCs, but lots of architectures don't; you need something > that will work when the architecture-specific dynamic linker support for > IFUNCs isn't present in glibc (or does this somehow not need that > support)? There is no particular reason to address this before a machine without IFUNC support gets the cleanups to start using pt-vfork.c. But here's a version of the ARM patch that preemptively handles the case. Thanks, Roland 2014-05-14 Roland McGrath * sysdeps/unix/sysv/linux/arm/vfork.S: Include . (__vfork): Incorporate save/restore of PID from nptl/vfork.S here. (__libc_vfork): New strong alias. * sysdeps/unix/sysv/linux/arm/nptl/vfork.S: File removed. * sysdeps/unix/sysv/linux/arm/nptl/pt-vfork.S: File removed. * nptl/pt-vfork.c: New file. * nptl/Versions (libc: GLIBC_PRIVATE): Add __libc_vfork. (libpthread: GLIBC_2.20): New version set (empty). --- a/nptl/Versions +++ b/nptl/Versions @@ -30,6 +30,7 @@ libc { __libc_alloca_cutoff; # Internal libc interface to libpthread __libc_dl_error_tsd; + __libc_vfork; } } @@ -257,6 +258,9 @@ libpthread { pthread_setattr_default_np; } + GLIBC_2.20 { + } + GLIBC_PRIVATE { __pthread_initialize_minimal; __pthread_clock_gettime; __pthread_clock_settime; --- /dev/null +++ b/nptl/pt-vfork.c @@ -0,0 +1,77 @@ +/* vfork ABI-compatibility entry points for libpthread. + Copyright (C) 2014 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 + . */ + +#include +#include + +/* libpthread used to have its own vfork implementation that differed + from libc's only in having a pointless micro-optimization. There + is no longer any use to having a separate copy in libpthread, but + the historical ABI requires it. For static linking, there is no + need to provide anything here--the libc version will be linked in. + For shared library ABI compatibility, there must be __vfork and + vfork symbols in libpthread.so; so we define them using IFUNC to + redirect to the libc function. */ + +#if (SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_20) \ + || SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_20)) + +extern __typeof (vfork) __libc_vfork; /* Defined in libc. */ + +# ifdef HAVE_IFUNC + +attribute_hidden __attribute__ ((used)) +__typeof (vfork) * +vfork_ifunc (void) +{ + return &__libc_vfork; +} + +# ifdef HAVE_ASM_SET_DIRECTIVE +# define DEFINE_VFORK(name) \ + asm (".set " #name ", vfork_ifunc\n" \ + ".globl " #name "\n" \ + ".type " #name ", %gnu_indirect_function"); +# else +# define DEFINE_VFORK(name) \ + asm (#name " = vfork_ifunc\n" \ + ".globl " #name "\n" \ + ".type " #name ", %gnu_indirect_function"); +# endif + +# else + +attribute_hidden +pid_t +vfork_compat (void) +{ + return __libc_vfork (); +} + +# define DEFINE_VFORK(name) weak_alias (vfork_compat, name) + +# endif +#endif + +#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_20) +DEFINE_VFORK (vfork) +#endif + +#if SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_20) +DEFINE_VFORK (__vfork) +#endif --- a/sysdeps/unix/sysv/linux/arm/nptl/pt-vfork.S +++ /dev/null @@ -1,34 +0,0 @@ -/* Copyright (C) 2005-2014 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 - . */ - -#include - -/* Save the PID value. */ -#define SAVE_PID \ - GET_TLS (r2); \ - NEGOFF_ADJ_BASE2 (r2, r0, PID_OFFSET); /* Save the TLS addr in r2. */ \ - ldr r3, NEGOFF_OFF1 (r2, PID_OFFSET); /* Load the saved PID. */ \ - rsb r0, r3, #0; /* Negate it. */ \ - str r0, NEGOFF_OFF1 (r2, PID_OFFSET); /* Store the temp PID. */ - -/* Restore the old PID value in the parent. */ -#define RESTORE_PID \ - cmp r0, #0; /* If we are the parent... */ \ - it ne; \ - strne r3, NEGOFF_OFF1 (r2, PID_OFFSET); /* restore the saved PID. */ - -#include "../vfork.S" --- a/sysdeps/unix/sysv/linux/arm/nptl/vfork.S +++ /dev/null @@ -1,36 +0,0 @@ -/* Copyright (C) 2005-2014 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 - . */ - -#include - -/* Save the PID value. */ -#define SAVE_PID \ - GET_TLS (r2); \ - NEGOFF_ADJ_BASE2 (r2, r0, PID_OFFSET); /* Save the TLS addr in r2. */ \ - ldr r3, NEGOFF_OFF1 (r2, PID_OFFSET); /* Load the saved PID. */ \ - rsbs r0, r3, #0; /* Negate it. */ \ - it eq; \ - moveq r0, #0x80000000; /* Use 0x80000000 if it was 0. */ \ - str r0, NEGOFF_OFF1 (r2, PID_OFFSET); /* Store the temp PID. */ - -/* Restore the old PID value in the parent. */ -#define RESTORE_PID \ - cmp r0, #0; /* If we are the parent... */ \ - it ne; \ - strne r3, NEGOFF_OFF1 (r2, PID_OFFSET); /* restore the saved PID. */ - -#include "../vfork.S" --- a/sysdeps/unix/sysv/linux/arm/vfork.S +++ b/sysdeps/unix/sysv/linux/arm/vfork.S @@ -19,6 +19,8 @@ #include #define _ERRNO_H 1 #include +#include + /* Clone the calling process, but without copying the whole address space. The calling process is suspended until the new process exits or is @@ -26,9 +28,16 @@ and the process ID of the new process to the old process. */ ENTRY (__vfork) -#ifdef SAVE_PID - SAVE_PID -#endif + /* Save the PID value. */ + GET_TLS (r2) + NEGOFF_ADJ_BASE2 (r2, r0, PID_OFFSET) /* Save the TLS addr in r2. */ + ldr r3, NEGOFF_OFF1 (r2, PID_OFFSET) /* Load the saved PID. */ + rsbs r0, r3, #0 /* Negate it, and test for zero. */ + /* Use 0x80000000 if it was 0. See raise.c for how this is used. */ + it eq + moveq r0, #0x80000000 + str r0, NEGOFF_OFF1 (r2, PID_OFFSET) /* Store the temp PID. */ + /* The DO_CALL macro saves r7 on the stack, to enable generation of ARM unwind info. Since the stack is initially shared between parent and child of vfork, that saved value could be corrupted. @@ -46,10 +55,13 @@ ENTRY (__vfork) add sp, sp, #4 cfi_adjust_cfa_offset (-4) mov r7, ip - cfi_restore (r7); -#ifdef RESTORE_PID - RESTORE_PID -#endif + cfi_restore (r7) + + /* Restore the old PID value in the parent. */ + cmp r0, #0 /* If we are the parent... */ + it ne + strne r3, NEGOFF_OFF1 (r2, PID_OFFSET) /* restore the saved PID. */ + cmn a1, #4096 it cc RETINSTR(cc, lr) @@ -59,3 +71,4 @@ PSEUDO_END (__vfork) libc_hidden_def (__vfork) weak_alias (__vfork, vfork) +strong_alias (__vfork, __libc_vfork)