[2/2,roland/nptl] x86: Consolidate NPTL/non versions of vfork

Message ID	20140513222221.CAF4E2C39DB@topped-with-meat.com
State	New
Headers	show Return-Path: <libc-alpha-return-49793-incoming=patchwork.ozlabs.org@sourceware.org> 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:in-reply-to :references:message-id:date; q=dns; s=default; b=Ke1Qu1qYw5pJu4G p9mCBW2n5FS/6CzWIPZldRbS8DaNDtgG82RdU1QTxLfXv75HS1xhyVG62G2esCe1 IH/Z/b/tL7lmrAnjl0TYROdP52weqJ//j+cLqs+VVxbQeceE1yhBPWhg9QXZ9lJ1 Q6MH9dKqVNNi9dnp5gS/3y+qN4LE= Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk Sender: libc-alpha-owner@sourceware.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath <roland@hack.frob.com> To: "GNU C. Library" <libc-alpha@sourceware.org> Subject: Re: [PATCH 2/2 roland/nptl] x86: Consolidate NPTL/non versions of vfork In-Reply-To: Roland McGrath's message of Tuesday, 13 May 2014 15:19:39 -0700 <20140513221939.A63F52C39B4@topped-with-meat.com> References: <20140513221939.A63F52C39B4@topped-with-meat.com> Message-Id: <20140513222221.CAF4E2C39DB@topped-with-meat.com> Date: Tue, 13 May 2014 15:22:21 -0700 (PDT)

--- a/nptl/sysdeps/unix/sysv/linux/i386/pt-vfork.S +++ /dev/null @@ -1,66 +0,0 @@ -/* Copyright (C) 1999-2014 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Andreas Schwab <schwab@gnu.org>. - - 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 - <http://www.gnu.org/licenses/>. */ - -#include <sysdep.h> -#define _ERRNO_H 1 -#include <bits/errno.h> -#include <kernel-features.h> -#include <tcb-offsets.h> - -/* Save the PID value. */ -#define SAVE_PID \ - movl %gs:PID, %edx; \ - movl %edx, %eax; \ - negl %eax; \ - movl %eax, %gs:PID - -/* Restore the old PID value in the parent. */ -#define RESTORE_PID \ - testl %eax, %eax; \ - je 1f; \ - movl %edx, %gs:PID; \ -1: - -/* Clone the calling process, but without copying the whole address space. - The calling process is suspended until the new process exits or is - replaced by a call to `execve'. Return -1 for errors, 0 to the new process, - and the process ID of the new process to the old process. */ - -ENTRY (__vfork) - /* Pop the return PC value into ECX. */ - popl %ecx - - SAVE_PID - - /* Stuff the syscall number in EAX and enter into the kernel. */ - movl $SYS_ify (vfork), %eax - int $0x80 - - RESTORE_PID - - /* Jump to the return PC. Don't jump directly since this - disturbs the branch target cache. Instead push the return - address back on the stack. */ - pushl %ecx - - cmpl $-4095, %eax - jae SYSCALL_ERROR_LABEL /* Branch forward if it failed. */ - ret -PSEUDO_END (__vfork) - -weak_alias (__vfork, vfork) --- a/nptl/sysdeps/unix/sysv/linux/i386/vfork.S +++ /dev/null @@ -1,44 +0,0 @@ -/* Copyright (C) 1999-2014 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 - <http://www.gnu.org/licenses/>. */ - -/* We want an #include_next, but we are the main source file. - So, #include ourselves and in that incarnation we can use #include_next. */ -#ifndef INCLUDED_SELF -# define INCLUDED_SELF -# include <vfork.S> -#else - -# include <tcb-offsets.h> - -/* Save the PID value. */ -# define SAVE_PID \ - movl %gs:PID, %edx; \ - movl %edx, %eax; \ - negl %eax; \ - jne 1f; \ - movl $0x80000000, %eax; \ -1: movl %eax, %gs:PID - -/* Restore the old PID value in the parent. */ -# define RESTORE_PID \ - testl %eax, %eax; \ - je 1f; \ - movl %edx, %gs:PID; \ -1: - -# include_next <vfork.S> -#endif --- a/nptl/sysdeps/unix/sysv/linux/x86_64/pt-vfork.S +++ /dev/null @@ -1,32 +0,0 @@ -/* Copyright (C) 2004-2014 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 - <http://www.gnu.org/licenses/>. */ - -#include <tcb-offsets.h> - -#define SAVE_PID \ - movl %fs:PID, %esi; \ - movl %esi, %edx; \ - negl %edx; \ - movl %edx, %fs:PID - -#define RESTORE_PID \ - testq %rax, %rax; \ - je 1f; \ - movl %esi, %fs:PID; \ -1: - -#include <../../../../../../sysdeps/unix/sysv/linux/x86_64/vfork.S> --- a/nptl/sysdeps/unix/sysv/linux/x86_64/vfork.S +++ /dev/null @@ -1,42 +0,0 @@ -/* Copyright (C) 2004-2014 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 - <http://www.gnu.org/licenses/>. */ - -/* We want an #include_next, but we are the main source file. - So, #include ourselves and in that incarnation we can use #include_next. */ -#ifndef INCLUDED_SELF -# define INCLUDED_SELF -# include <vfork.S> -#else - -# include <tcb-offsets.h> - -# define SAVE_PID \ - movl %fs:PID, %esi; \ - movl $0x80000000, %ecx; \ - movl %esi, %edx; \ - negl %edx; \ - cmove %ecx, %edx; \ - movl %edx, %fs:PID - -# define RESTORE_PID \ - testq %rax, %rax; \ - je 1f; \ - movl %esi, %fs:PID; \ -1: - -# include_next <vfork.S> -#endif --- a/sysdeps/unix/sysv/linux/i386/vfork.S +++ b/sysdeps/unix/sysv/linux/i386/vfork.S @@ -20,6 +20,8 @@ #define _ERRNO_H 1 #include <bits/errno.h> #include <kernel-features.h> +#include <tcb-offsets.h> + /* Clone the calling process, but without copying the whole address space. The calling process is suspended until the new process exits or is @@ -33,9 +35,16 @@ ENTRY (__vfork) cfi_adjust_cfa_offset (-4) cfi_register (%eip, %ecx) -#ifdef SAVE_PID - SAVE_PID -#endif + /* Save the TCB-cached PID away in %edx, and then negate the TCB + field. But if it's zero, set it to 0x80000000 instead. See + raise.c for the logic that relies on this value. */ + movl %gs:PID, %edx + movl %edx, %eax + negl %eax + jne 1f + movl $0x80000000, %eax +1: movl %eax, %gs:PID + /* Stuff the syscall number in EAX and enter into the kernel. */ movl $SYS_ify (vfork), %eax @@ -47,9 +56,13 @@ ENTRY (__vfork) pushl %ecx cfi_adjust_cfa_offset (4) -#ifdef RESTORE_PID - RESTORE_PID -#endif + /* Restore the original value of the TCB cache of the PID, if we're + the parent. But in the child (syscall return value equals zero), + leave things as they are. */ + testl %eax, %eax + je 1f + movl %edx, %gs:PID +1: cmpl $-4095, %eax /* Branch forward if it failed. */ @@ -61,3 +74,4 @@ PSEUDO_END (__vfork) libc_hidden_def (__vfork) weak_alias (__vfork, vfork) +strong_alias (__vfork, __libc_vfork) --- a/sysdeps/unix/sysv/linux/x86_64/vfork.S +++ b/sysdeps/unix/sysv/linux/x86_64/vfork.S @@ -18,6 +18,8 @@ #include <sysdep.h> #define _ERRNO_H 1 #include <bits/errno.h> +#include <tcb-offsets.h> + /* Clone the calling process, but without copying the whole address space. The calling process is suspended until the new process exits or is @@ -32,9 +34,15 @@ ENTRY (__vfork) cfi_adjust_cfa_offset(-8) cfi_register(%rip, %rdi) -#ifdef SAVE_PID - SAVE_PID -#endif + /* Save the TCB-cached PID away in %esi, and then negate the TCB + field. But if it's zero, set it to 0x80000000 instead. See + raise.c for the logic that relies on this value. */ + movl %fs:PID, %esi + movl $0x80000000, %ecx + movl %esi, %edx + negl %edx + cmove %ecx, %edx + movl %edx, %fs:PID /* Stuff the syscall number in RAX and enter into the kernel. */ movl $SYS_ify (vfork), %eax @@ -44,9 +52,13 @@ ENTRY (__vfork) pushq %rdi cfi_adjust_cfa_offset(8) -#ifdef RESTORE_PID - RESTORE_PID -#endif + /* Restore the original value of the TCB cache of the PID, if we're + the parent. But in the child (syscall return value equals zero), + leave things as they are. */ + testq %rax, %rax + je 1f + movl %esi, %fs:PID +1: cmpl $-4095, %eax jae SYSCALL_ERROR_LABEL /* Branch forward if it failed. */ @@ -58,3 +70,4 @@ PSEUDO_END (__vfork) libc_hidden_def (__vfork) weak_alias (__vfork, vfork) +strong_alias (__vfork, __libc_vfork)

[2/2,roland/nptl] x86: Consolidate NPTL/non versions of vfork

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