From patchwork Tue May 13 22:19:39 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roland McGrath X-Patchwork-Id: 895 Return-Path: X-Original-To: siddhesh@wilcox.dreamhost.com Delivered-To: siddhesh@wilcox.dreamhost.com Received: from homiemail-mx21.g.dreamhost.com (peon2454.g.dreamhost.com [208.113.200.127]) by wilcox.dreamhost.com (Postfix) with ESMTP id 6BA9F3600BE for ; Tue, 13 May 2014 15:19:48 -0700 (PDT) Received: by homiemail-mx21.g.dreamhost.com (Postfix, from userid 14307373) id D6DE31A5B375; Tue, 13 May 2014 15:19:47 -0700 (PDT) X-Original-To: glibc@patchwork.siddhesh.in Delivered-To: x14307373@homiemail-mx21.g.dreamhost.com 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 homiemail-mx21.g.dreamhost.com (Postfix) with ESMTPS id 8EA6E1A73007 for ; Tue, 13 May 2014 15:19:47 -0700 (PDT) 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:subject:message-id:date; q= dns; s=default; b=vmsRsIv2BfgNNOhV021k4AR5pngU8VXChgLuff3PBJ2PWg Sdx6wwdTBvH4fqQF6Hu9UfQZSld/gBP44XIE9i+26tKBsE3t3RxnTQ04XB+BiAqj Dh+SzMmTfl0A7dPdd9RB2VVlfLhbnznhkA0TytH8ll2Rnow3qSGxK2Cg30Hqw= 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:subject:message-id:date; s= default; bh=mmMewdWK4RKGLDn8YkVm1Htjdrk=; b=Qu+n94LCPWcTtbSw/2kk 5Yk++M+Y8bcLpfphWEsoUcOze5P6u85YIdoGwAGeZUPsuISZgScX4jEAvEPkY2oG gGdtfAeN8UDSHtvFNjhRVcRrRItcygYrcXd77uMc4N5mH7rEdx9ren/862LF4dj1 COikyrkSkX7V3m5tp9sHeYM= Received: (qmail 27520 invoked by alias); 13 May 2014 22:19:44 -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 27508 invoked by uid 89); 13 May 2014 22:19:43 -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: "GNU C. Library" Subject: [PATCH 1/2 roland/nptl] ARM: Consolidate NPTL/non versions of vfork Message-Id: <20140513221939.A63F52C39B4@topped-with-meat.com> Date: Tue, 13 May 2014 15:19:39 -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=kAT-4RBKDbMA:10 a=Z6MIti7PxpgA:10 a=kj9zAlcOel0A:10 a=hOe2yjtxAAAA:8 a=mDV3o1hIAAAA:8 a=DvBSG1bP4tg-ZFA9zt4A:9 a=-HeAwq0aH_F1cd2a:21 a=J03voxxQkR6Pbp18:21 a=CjuIK1q_8ugA:10 X-DH-Original-To: glibc@patchwork.siddhesh.in This change completes the removal of the sysdeps/unix/sysv/linux/arm/nptl/ subdirectory. As discussed in another thread, the difference between libc's vfork and libpthread's vfork is a pointless micro-optimization in the libpthread version. Saving the tiny number of instructions (just one in the ARM code) in the libpthread version is not worth the complexity and bloat of having two separate versions. The presence of vfork/__vfork in the historical libpthread.so ABI means we can't just get rid of pt-vfork entirely. Instead, I've implemented the ABI compatibility generically in nptl/pt-vfork.c, using IFUNC redirectors so libpthread's symbols resolve to libc's function. This will serve other machines as they clean out their old pt-vfork.S files too. Verified on arm-linux-gnueabihf that posix/vfork.os code does not change, and that check-abi still passes. (libc.so cannot be compared directly because .dynsym grew and changed all the addresses.) OK? Thanks, Roland * 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 +1,63 @@ +/* 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. */ + +attribute_hidden __attribute__ ((used)) +__typeof (vfork) * +vfork_ifunc (void) +{ + return &__libc_vfork; +} + +#endif + +#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 + +#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)