unofficial mirror of libc-alpha@sourceware.org
 help / color / mirror / Atom feed
From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org
Subject: Re: [PATCH 1/3] Refactor Linux ARCH_FORK implementation
Date: Wed, 7 Mar 2018 13:51:03 -0300	[thread overview]
Message-ID: <b7d456e7-3ffc-ae6c-a52a-c509218fb170@linaro.org> (raw)
In-Reply-To: <1518008967-8310-1-git-send-email-adhemerval.zanella@linaro.org>


If no one opposes I will commit it this shortly.

On 07/02/2018 11:09, Adhemerval Zanella wrote:
> This patch refactors the ARCH_FORK macro and the required architecture
> specific header to simplify the required architecture definitions
> to provide the fork syscall semantic and proper document current
> Linux clone ABI variant.
> 
> Instead of require the reimplementation of arch-fork.h header, this
> patch changes the ARCH_FORK to an inline function with clone ABI
> defined by kernel-features.h define.  The generic kernel ABI meant
> for newer ports is used as default and redefine if the architecture
> requires.
> 
> Checked on x86_64-linux-gnu and i686-linux-gnu.  Also with a build
> for all the afected ABIs.
> 
> 	* sysdeps/nptl/fork.c (ARCH_FORK): Replace by auch_fork.
> 	* sysdeps/unix/sysv/linux/alpha/arch-fork.h: Remove file.
> 	* sysdeps/unix/sysv/linux/riscv/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/aarch64/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/arm/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/hppa/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/i386/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/ia64/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/m68k/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/microblaze/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/mips/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/nios2/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/powerpc/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/s390/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/sh/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/sparc/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/tile/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/x86_64/arch-fork.h: Likewise.
> 	* sysdeps/unix/sysv/linux/arch-fork.h (arch_fork): New function.
> 	* sysdeps/unix/sysv/linux/aarch64/kernel-features.h: New file.
> 	* sysdeps/unix/sysv/linux/riscv/kernel-features.h: Likewise.
> 	* sysdeps/unix/sysv/linux/arm/kernel-features.h
> 	(__ASSUME_CLONE_BACKWARDS): Define.
> 	* sysdeps/unix/sysv/linux/createthread.c (ARCH_CLONE): Define to
> 	__clone2 if __NR_clone2 is defined.
> 	* sysdeps/unix/sysv/linux/hppa/kernel-features.h
> 	(__ASSUME_CLONE_BACKWARDS): Likewise.
> 	* sysdeps/unix/sysv/linux/i386/kernel-features.h
> 	(__ASSUME_CLONE_BACKWARDS): Likewise.
> 	* sysdeps/unix/sysv/linux/ia64/kernel-features.h
> 	(__ASSUME_CLONE2): Likewise.
> 	* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
> 	(__ASSUME_CLONE_BACKWARDS3): Likewise.
> 	* sysdeps/unix/sysv/linux/kernel-features.h: Document possible clone
> 	variants and the define architecture can use.
> 	(__ASSUME_CLONE_DEFAULT): Define as default.
> 	* sysdeps/unix/sysv/linux/mips/kernel-features.h
> 	(__ASSUME_CLONE_BACKWARDS): Likewise.
> 	* sysdeps/unix/sysv/linux/powerpc/kernel-features.h
> 	(__ASSUME_CLONE_BACKWARDS): Likewise.
> 	* sysdeps/unix/sysv/linux/s390/kernel-features.h
> 	(__ASSUME_CLONE_BACKWARDS2): Likewise.
> ---
>  ChangeLog                                          | 45 ++++++++++++++++++++++
>  sysdeps/nptl/fork.c                                |  8 +---
>  .../arch-fork.h => aarch64/kernel-features.h}      | 15 +++-----
>  sysdeps/unix/sysv/linux/alpha/arch-fork.h          | 28 --------------
>  sysdeps/unix/sysv/linux/arch-fork.h                | 44 ++++++++++++++++-----
>  sysdeps/unix/sysv/linux/arm/arch-fork.h            | 27 -------------
>  sysdeps/unix/sysv/linux/arm/kernel-features.h      |  3 ++
>  sysdeps/unix/sysv/linux/createthread.c             |  5 ++-
>  sysdeps/unix/sysv/linux/hppa/arch-fork.h           | 32 ---------------
>  sysdeps/unix/sysv/linux/hppa/kernel-features.h     |  3 ++
>  sysdeps/unix/sysv/linux/i386/arch-fork.h           | 27 -------------
>  sysdeps/unix/sysv/linux/i386/kernel-features.h     |  3 ++
>  sysdeps/unix/sysv/linux/ia64/arch-fork.h           | 31 ---------------
>  sysdeps/unix/sysv/linux/ia64/kernel-features.h     |  3 ++
>  sysdeps/unix/sysv/linux/kernel-features.h          | 35 +++++++++++++++++
>  sysdeps/unix/sysv/linux/m68k/arch-fork.h           | 28 --------------
>  sysdeps/unix/sysv/linux/microblaze/arch-fork.h     | 27 -------------
>  .../unix/sysv/linux/microblaze/kernel-features.h   |  3 ++
>  sysdeps/unix/sysv/linux/mips/arch-fork.h           |  1 -
>  sysdeps/unix/sysv/linux/mips/kernel-features.h     |  3 ++
>  sysdeps/unix/sysv/linux/nios2/arch-fork.h          | 33 ----------------
>  sysdeps/unix/sysv/linux/powerpc/arch-fork.h        |  1 -
>  sysdeps/unix/sysv/linux/powerpc/kernel-features.h  |  3 ++
>  .../arch-fork.h => riscv/kernel-features.h}        | 17 +++-----
>  sysdeps/unix/sysv/linux/s390/arch-fork.h           | 29 --------------
>  sysdeps/unix/sysv/linux/s390/kernel-features.h     |  3 ++
>  sysdeps/unix/sysv/linux/sh/arch-fork.h             | 28 --------------
>  sysdeps/unix/sysv/linux/sparc/arch-fork.h          | 27 -------------
>  sysdeps/unix/sysv/linux/tile/arch-fork.h           | 29 --------------
>  sysdeps/unix/sysv/linux/x86_64/arch-fork.h         | 27 -------------
>  30 files changed, 155 insertions(+), 413 deletions(-)
>  rename sysdeps/unix/sysv/linux/{riscv/arch-fork.h => aarch64/kernel-features.h} (67%)
>  delete mode 100644 sysdeps/unix/sysv/linux/alpha/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/arm/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/hppa/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/i386/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/ia64/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/m68k/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/microblaze/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/mips/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/nios2/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/powerpc/arch-fork.h
>  rename sysdeps/unix/sysv/linux/{aarch64/arch-fork.h => riscv/kernel-features.h} (66%)
>  delete mode 100644 sysdeps/unix/sysv/linux/s390/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/sh/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/sparc/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/tile/arch-fork.h
>  delete mode 100644 sysdeps/unix/sysv/linux/x86_64/arch-fork.h
> 
> diff --git a/sysdeps/nptl/fork.c b/sysdeps/nptl/fork.c
> index 846fa49..0061ee0 100644
> --- a/sysdeps/nptl/fork.c
> +++ b/sysdeps/nptl/fork.c
> @@ -131,13 +131,7 @@ __libc_fork (void)
>        call_function_static_weak (__malloc_fork_lock_parent);
>      }
>  
> -#ifdef ARCH_FORK
> -  pid = ARCH_FORK ();
> -#else
> -# error "ARCH_FORK must be defined so that the CLONE_SETTID flag is used"
> -  pid = INLINE_SYSCALL (fork, 0);
> -#endif
> -
> +  pid = arch_fork (&THREAD_SELF->tid);
>  
>    if (pid == 0)
>      {
> diff --git a/sysdeps/unix/sysv/linux/riscv/arch-fork.h b/sysdeps/unix/sysv/linux/aarch64/kernel-features.h
> similarity index 67%
> rename from sysdeps/unix/sysv/linux/riscv/arch-fork.h
> rename to sysdeps/unix/sysv/linux/aarch64/kernel-features.h
> index f6f5d73..9cfa514 100644
> --- a/sysdeps/unix/sysv/linux/riscv/arch-fork.h
> +++ b/sysdeps/unix/sysv/linux/aarch64/kernel-features.h
> @@ -1,5 +1,6 @@
> -/* Internal definitions for thread-friendly fork implementation.  Linux/RISC-V.
> -   Copyright (C) 2002-2018 Free Software Foundation, Inc.
> +/* Set flags signalling availability of kernel features based on given
> +   kernel version number.  AArch64 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
> @@ -16,11 +17,7 @@
>     License along with the GNU C Library; if not, see
>     <http://www.gnu.org/licenses/>.  */
>  
> -#include <sched.h>
> -#include <sysdep.h>
> -#include <tls.h>
> +#include_next <kernel-features.h>
>  
> -#define ARCH_FORK() \
> -  INLINE_SYSCALL (clone, 5,						      \
> -		  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD, 0,     \
> -		  NULL, NULL, &THREAD_SELF->tid)
> +#undef __ASSUME_CLONE_DEFAULT
> +#define __ASSUME_CLONE_BACKWARDS 1
> diff --git a/sysdeps/unix/sysv/linux/alpha/arch-fork.h b/sysdeps/unix/sysv/linux/alpha/arch-fork.h
> deleted file mode 100644
> index 41897dc..0000000
> --- a/sysdeps/unix/sysv/linux/alpha/arch-fork.h
> +++ /dev/null
> @@ -1,28 +0,0 @@
> -/* ARCH_FORK definition for Linux fork implementation.  Alpha version.
> -   Copyright (C) 2003-2018 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
> -   <http://www.gnu.org/licenses/>.  */
> -
> -#include <sched.h>
> -#include <signal.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -
> -#define ARCH_FORK()							\
> -  INLINE_SYSCALL (clone, 5,						\
> -		  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD,	\
> -		  NULL, NULL, &THREAD_SELF->tid, NULL)
> diff --git a/sysdeps/unix/sysv/linux/arch-fork.h b/sysdeps/unix/sysv/linux/arch-fork.h
> index d5f5429..62bc23d 100644
> --- a/sysdeps/unix/sysv/linux/arch-fork.h
> +++ b/sysdeps/unix/sysv/linux/arch-fork.h
> @@ -1,4 +1,4 @@
> -/* ARCH_FORK definition for Linux fork implementation.  Stub version.
> +/* arch_fork definition for Linux fork implementation.
>     Copyright (C) 2014-2018 Free Software Foundation, Inc.
>     This file is part of the GNU C Library.
>  
> @@ -16,12 +16,38 @@
>     License along with the GNU C Library; if not, see
>     <http://www.gnu.org/licenses/>.  */
>  
> -/* This file should define the function-like macro of no arguments
> -   ARCH_FORK to an INLINE_SYSCALL invocation of the clone-like system
> -   call, passing the CLONE_CHILD_SETTID and CLONE_CHILD_CLEARTID flags
> -   and &THREAD_SELF->tid as the TID address.
> +#ifndef __ARCH_FORK_H
> +#define __ARCH_FORK_H
>  
> -   Machines that lack an arch-fork.h header file will hit an #error in
> -   fork.c; this stub file doesn't contain an #error itself mainly for
> -   the transition period of migrating old machine-specific fork.c files
> -   to machine-specific arch-fork.h instead.  */
> +#include <unistd.h>
> +
> +/* Call the clone syscall with fork semantic.  The CTID address is used
> +   to both store the child thread ID at its location and and erase it
> +   in child memory when the child exits, and do a wakeup on the futex at
> +   that address.
> +
> +   The architecture with non-default kernel abi semantic should correctlly
> +   override it with one of the supported calling convention (check generic
> +   kernel-features.h for the clone abi variants).  */
> +static inline pid_t
> +arch_fork (void *ctid)
> +{
> +  const int flags = CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD;
> +  long int ret;
> +#ifdef __ASSUME_CLONE_BACKWARDS
> +  ret = INLINE_SYSCALL_CALL (clone, flags, 0, NULL, 0, ctid);
> +#elif defined(__ASSUME_CLONE_BACKWARDS2)
> +  ret = INLINE_SYSCALL_CALL (clone, 0, flags, NULL, ctid, 0);
> +#elif defined(__ASSUME_CLONE_BACKWARDS3)
> +  ret = INLINE_SYSCALL_CALL (clone, flags, 0, 0, NULL, ctid, 0);
> +#elif defined(__ASSUME_CLONE2)
> +  ret = INLINE_SYSCALL_CALL (clone2, flags, 0, 0, NULL, ctid, 0);
> +#elif defined(__ASSUME_CLONE_DEFAULT)
> +  ret = INLINE_SYSCALL_CALL (clone, flags, NULL, NULL, ctid, 0);
> +#else
> +# error "Undefined clone variant"
> +#endif
> +  return ret;
> +}
> +
> +#endif /* __ARCH_FORK_H  */
> diff --git a/sysdeps/unix/sysv/linux/arm/arch-fork.h b/sysdeps/unix/sysv/linux/arm/arch-fork.h
> deleted file mode 100644
> index ff3bc90..0000000
> --- a/sysdeps/unix/sysv/linux/arm/arch-fork.h
> +++ /dev/null
> @@ -1,27 +0,0 @@
> -/* ARCH_FORK definition for Linux fork implementation.  ARM version.
> -   Copyright (C) 2014-2018 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
> -   <http://www.gnu.org/licenses/>.  */
> -
> -#include <sched.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -
> -#define ARCH_FORK()                                                     \
> -  INLINE_SYSCALL (clone, 5,                                             \
> -                  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD,  \
> -                  NULL, NULL, NULL, &THREAD_SELF->tid)
> diff --git a/sysdeps/unix/sysv/linux/arm/kernel-features.h b/sysdeps/unix/sysv/linux/arm/kernel-features.h
> index f13632b..7831ab1 100644
> --- a/sysdeps/unix/sysv/linux/arm/kernel-features.h
> +++ b/sysdeps/unix/sysv/linux/arm/kernel-features.h
> @@ -39,3 +39,6 @@
>  
>  #define __ASSUME_RECV_SYSCALL   1
>  #define __ASSUME_SEND_SYSCALL	1
> +
> +#undef __ASSUME_CLONE_DEFAULT
> +#define __ASSUME_CLONE_BACKWARDS	1
> diff --git a/sysdeps/unix/sysv/linux/createthread.c b/sysdeps/unix/sysv/linux/createthread.c
> index 5b5464a..5879e51 100644
> --- a/sysdeps/unix/sysv/linux/createthread.c
> +++ b/sysdeps/unix/sysv/linux/createthread.c
> @@ -28,8 +28,9 @@
>  
>  #include <arch-fork.h>
>  
> -
> -#ifndef ARCH_CLONE
> +#ifdef __NR_clone2
> +# define ARCH_CLONE __clone2
> +#else
>  # define ARCH_CLONE __clone
>  #endif
>  
> diff --git a/sysdeps/unix/sysv/linux/hppa/arch-fork.h b/sysdeps/unix/sysv/linux/hppa/arch-fork.h
> deleted file mode 100644
> index 7d52994..0000000
> --- a/sysdeps/unix/sysv/linux/hppa/arch-fork.h
> +++ /dev/null
> @@ -1,32 +0,0 @@
> -/* ARCH_FORK definition for Linux fork implementation.  HPPA version.
> -   Copyright (C) 2005-2018 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
> -   <http://www.gnu.org/licenses/>.  */
> -
> -#include <sched.h>
> -#include <signal.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -/* Argument 1 - Clone flags.
> -            2 - Child stack pointer.
> -	    3 - Parent tid pointer.
> -	    4 - New TLS area pointer.
> -	    5 - Child tid pointer. */
> -#define ARCH_FORK() \
> -  INLINE_SYSCALL (clone, 5,						\
> -		  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD,	\
> -                  NULL, NULL, NULL, &THREAD_SELF->tid)
> diff --git a/sysdeps/unix/sysv/linux/hppa/kernel-features.h b/sysdeps/unix/sysv/linux/hppa/kernel-features.h
> index 3f005a5..ef3c4dd 100644
> --- a/sysdeps/unix/sysv/linux/hppa/kernel-features.h
> +++ b/sysdeps/unix/sysv/linux/hppa/kernel-features.h
> @@ -32,3 +32,6 @@
>  #if __LINUX_KERNEL_VERSION < 0x040000
>  # undef __ASSUME_EXECVEAT
>  #endif
> +
> +#undef __ASSUME_CLONE_DEFAULT
> +#define __ASSUME_CLONE_BACKWARDS 1
> diff --git a/sysdeps/unix/sysv/linux/i386/arch-fork.h b/sysdeps/unix/sysv/linux/i386/arch-fork.h
> deleted file mode 100644
> index 0c43e2f..0000000
> --- a/sysdeps/unix/sysv/linux/i386/arch-fork.h
> +++ /dev/null
> @@ -1,27 +0,0 @@
> -/* Internal definitions for thread-friendly fork implementation.  Linux/i386.
> -   Copyright (C) 2002-2018 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
> -
> -   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 <sched.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -#define ARCH_FORK() \
> -  INLINE_SYSCALL (clone, 5,						      \
> -		  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD, 0,     \
> -		  NULL, NULL, &THREAD_SELF->tid)
> diff --git a/sysdeps/unix/sysv/linux/i386/kernel-features.h b/sysdeps/unix/sysv/linux/i386/kernel-features.h
> index 8708712..f3cfd48 100644
> --- a/sysdeps/unix/sysv/linux/i386/kernel-features.h
> +++ b/sysdeps/unix/sysv/linux/i386/kernel-features.h
> @@ -48,3 +48,6 @@
>  
>  /* i686 only supports ipc syscall.  */
>  #undef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
> +
> +#undef __ASSUME_CLONE_DEFAULT
> +#define __ASSUME_CLONE_BACKWARDS	1
> diff --git a/sysdeps/unix/sysv/linux/ia64/arch-fork.h b/sysdeps/unix/sysv/linux/ia64/arch-fork.h
> deleted file mode 100644
> index 522712e..0000000
> --- a/sysdeps/unix/sysv/linux/ia64/arch-fork.h
> +++ /dev/null
> @@ -1,31 +0,0 @@
> -/* ARCH_FORK definition for Linux fork implementation.  IA64 version.
> -   Copyright (C) 2003-2018 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -   Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
> -
> -   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 <sched.h>
> -#include <signal.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -
> -#define ARCH_FORK() \
> -  INLINE_SYSCALL (clone2, 6,						      \
> -		  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD,	      \
> -		  NULL, 0, NULL, &THREAD_SELF->tid, NULL)
> -
> -#define ARCH_CLONE __clone2
> diff --git a/sysdeps/unix/sysv/linux/ia64/kernel-features.h b/sysdeps/unix/sysv/linux/ia64/kernel-features.h
> index cc3fe92..04cdf43 100644
> --- a/sysdeps/unix/sysv/linux/ia64/kernel-features.h
> +++ b/sysdeps/unix/sysv/linux/ia64/kernel-features.h
> @@ -26,4 +26,7 @@
>  #define __ASSUME_SEND_SYSCALL		1
>  #define __ASSUME_ACCEPT4_SYSCALL	1
>  
> +#undef __ASSUME_CLONE_DEFAULT
> +#define __ASSUME_CLONE2
> +
>  #endif /* _KERNEL_FEATURES_H */
> diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
> index 3aa2052..ca18f0b 100644
> --- a/sysdeps/unix/sysv/linux/kernel-features.h
> +++ b/sysdeps/unix/sysv/linux/kernel-features.h
> @@ -115,3 +115,38 @@
>  #if __LINUX_KERNEL_VERSION >= 0x040500
>  # define __ASSUME_COPY_FILE_RANGE 1
>  #endif
> +
> +/* Support for clone call used on fork.  The signature varies across the
> +   architectures with current 4 different variants:
> +
> +   1. long int clone (unsigned long flags, unsigned long newsp,
> +		      int *parent_tidptr, unsigned long tls,
> +		      int *child_tidptr)
> +
> +   2. long int clone (unsigned long newsp, unsigned long clone_flags,
> +		      int *parent_tidptr, int * child_tidptr,
> +		      unsigned long tls)
> +
> +   3. long int clone (unsigned long flags, unsigned long newsp,
> +		      int stack_size, int *parent_tidptr,
> +		      int *child_tidptr, unsigned long tls)
> +
> +   4. long int clone (unsigned long flags, unsigned long newsp,
> +		      int *parent_tidptr, int *child_tidptr,
> +                      unsigned long tls)
> +
> +   The fourth variant is intended to be used as the default for newer ports,
> +   ALso IA64 uses the third variant but with __NR_clone2 instead of
> +   __NR_clone.
> +
> +   The macros names to define the variant used for the architecture is
> +   similar to kernel:
> +
> +   - __ASSUME_CLONE_BACKWARDS: for variant 1.
> +   - __ASSUME_CLONE_BACKWARDS2: for variant 2 (s390).
> +   - __ASSUME_CLONE_BACKWARDS3: for variant 3 (microblaze).
> +   - __ASSUME_CLONE_DEFAULT: for variant 4.
> +   - __ASSUME_CLONE2: for clone2 with variant 3 (ia64).
> +   */
> +
> +#define __ASSUME_CLONE_DEFAULT 1
> diff --git a/sysdeps/unix/sysv/linux/m68k/arch-fork.h b/sysdeps/unix/sysv/linux/m68k/arch-fork.h
> deleted file mode 100644
> index 20b6bab..0000000
> --- a/sysdeps/unix/sysv/linux/m68k/arch-fork.h
> +++ /dev/null
> @@ -1,28 +0,0 @@
> -/* ARCH_FORK definition for Linux fork implementation.  m68k version.
> -   Copyright (C) 2010-2018 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -   Contributed by Maxim Kuvyrkov <maxim@codesourcery.com>, 2010.
> -
> -   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 <sched.h>
> -#include <signal.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -#define ARCH_FORK() \
> -  INLINE_SYSCALL (clone, 5,						      \
> -		  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD, 0,     \
> -		  NULL, &THREAD_SELF->tid, NULL)
> diff --git a/sysdeps/unix/sysv/linux/microblaze/arch-fork.h b/sysdeps/unix/sysv/linux/microblaze/arch-fork.h
> deleted file mode 100644
> index 05ed4fa..0000000
> --- a/sysdeps/unix/sysv/linux/microblaze/arch-fork.h
> +++ /dev/null
> @@ -1,27 +0,0 @@
> -/* ARCH_FORK definition for Linux fork implementation.  MicroBlaze version.
> -   Copyright (C) 2014-2018 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
> -   <http://www.gnu.org/licenses/>.  */
> -
> -#include <sched.h>
> -#include <signal.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -#define ARCH_FORK()                                                           \
> -  INLINE_SYSCALL (clone, 5,                                                   \
> -                  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD, 0,     \
> -                  NULL, NULL, &THREAD_SELF->tid)
> diff --git a/sysdeps/unix/sysv/linux/microblaze/kernel-features.h b/sysdeps/unix/sysv/linux/microblaze/kernel-features.h
> index 745f899..b13b863 100644
> --- a/sysdeps/unix/sysv/linux/microblaze/kernel-features.h
> +++ b/sysdeps/unix/sysv/linux/microblaze/kernel-features.h
> @@ -57,3 +57,6 @@
>  #if __LINUX_KERNEL_VERSION < 0x040A00
>  # undef __ASSUME_COPY_FILE_RANGE
>  #endif
> +
> +#undef __ASSUME_CLONE_DEFAULT
> +#define __ASSUME_CLONE_BACKWARDS3
> diff --git a/sysdeps/unix/sysv/linux/mips/arch-fork.h b/sysdeps/unix/sysv/linux/mips/arch-fork.h
> deleted file mode 100644
> index 5f94537..0000000
> --- a/sysdeps/unix/sysv/linux/mips/arch-fork.h
> +++ /dev/null
> @@ -1 +0,0 @@
> -#include <sysdeps/unix/sysv/linux/i386/arch-fork.h>
> diff --git a/sysdeps/unix/sysv/linux/mips/kernel-features.h b/sysdeps/unix/sysv/linux/mips/kernel-features.h
> index 7756a34..a9009fb 100644
> --- a/sysdeps/unix/sysv/linux/mips/kernel-features.h
> +++ b/sysdeps/unix/sysv/linux/mips/kernel-features.h
> @@ -47,3 +47,6 @@
>  #if _MIPS_SIM == _ABIN32
>  # define __ASSUME_WORDSIZE64_ILP32	1
>  #endif
> +
> +#undef __ASSUME_CLONE_DEFAULT
> +#define __ASSUME_CLONE_BACKWARDS
> diff --git a/sysdeps/unix/sysv/linux/nios2/arch-fork.h b/sysdeps/unix/sysv/linux/nios2/arch-fork.h
> deleted file mode 100644
> index 6dacec2..0000000
> --- a/sysdeps/unix/sysv/linux/nios2/arch-fork.h
> +++ /dev/null
> @@ -1,33 +0,0 @@
> -/* ARCH_FORK definition for Linux fork implementation.  Nios II version.
> -   Copyright (C) 2005-2018 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
> -   <http://www.gnu.org/licenses/>.  */
> -
> -#include <sched.h>
> -#include <signal.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -/* Argument 1 - Clone flags.
> -            2 - Child stack pointer.
> -	    3 - Parent tid pointer.
> -	    4 - Child tid pointer.
> -	    5 - New TLS area pointer. */
> -
> -#define ARCH_FORK() \
> -  INLINE_SYSCALL (clone, 5,						\
> -		  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD,	\
> -                  NULL, NULL, &THREAD_SELF->tid, NULL)
> diff --git a/sysdeps/unix/sysv/linux/powerpc/arch-fork.h b/sysdeps/unix/sysv/linux/powerpc/arch-fork.h
> deleted file mode 100644
> index 5f94537..0000000
> --- a/sysdeps/unix/sysv/linux/powerpc/arch-fork.h
> +++ /dev/null
> @@ -1 +0,0 @@
> -#include <sysdeps/unix/sysv/linux/i386/arch-fork.h>
> diff --git a/sysdeps/unix/sysv/linux/powerpc/kernel-features.h b/sysdeps/unix/sysv/linux/powerpc/kernel-features.h
> index f3c02e6..503f562 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/kernel-features.h
> +++ b/sysdeps/unix/sysv/linux/powerpc/kernel-features.h
> @@ -49,3 +49,6 @@
>  
>  /* powerpc only supports ipc syscall.  */
>  #undef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
> +
> +#undef __ASSUME_CLONE_DEFAULT
> +#define __ASSUME_CLONE_BACKWARDS	1
> diff --git a/sysdeps/unix/sysv/linux/aarch64/arch-fork.h b/sysdeps/unix/sysv/linux/riscv/kernel-features.h
> similarity index 66%
> rename from sysdeps/unix/sysv/linux/aarch64/arch-fork.h
> rename to sysdeps/unix/sysv/linux/riscv/kernel-features.h
> index cab797e..37f4d99 100644
> --- a/sysdeps/unix/sysv/linux/aarch64/arch-fork.h
> +++ b/sysdeps/unix/sysv/linux/riscv/kernel-features.h
> @@ -1,5 +1,6 @@
> -/* ARCH_FORK definition for Linux fork implementation.  AArch64 version.
> -   Copyright (C) 2005-2018 Free Software Foundation, Inc.
> +/* Set flags signalling availability of kernel features based on given
> +   kernel version number.  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
> @@ -16,13 +17,7 @@
>     License along with the GNU C Library; if not, see
>     <http://www.gnu.org/licenses/>.  */
>  
> -#include <sched.h>
> -#include <signal.h>
> -#include <sysdep.h>
> -#include <tls.h>
> +#include_next <kernel-features.h>
>  
> -
> -#define ARCH_FORK()							\
> -  INLINE_SYSCALL (clone, 5,						\
> -		  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD,	\
> -		  NULL, NULL, NULL, &THREAD_SELF->tid)
> +#undef __ASSUME_CLONE_DEFAULT
> +#define __ASSUME_CLONE_BACKWARDS 1
> diff --git a/sysdeps/unix/sysv/linux/s390/arch-fork.h b/sysdeps/unix/sysv/linux/s390/arch-fork.h
> deleted file mode 100644
> index 152b465..0000000
> --- a/sysdeps/unix/sysv/linux/s390/arch-fork.h
> +++ /dev/null
> @@ -1,29 +0,0 @@
> -/* ARCH_FORK definition for Linux fork implementation. S390 version.
> -   Copyright (C) 2003-2018 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -   Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
> -
> -   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 <sched.h>
> -#include <signal.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -
> -#define ARCH_FORK() \
> -  INLINE_SYSCALL (clone, 5,						      \
> -		  0, CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD,     \
> -		  NULL, &THREAD_SELF->tid, NULL)
> diff --git a/sysdeps/unix/sysv/linux/s390/kernel-features.h b/sysdeps/unix/sysv/linux/s390/kernel-features.h
> index 3caca98..f718264 100644
> --- a/sysdeps/unix/sysv/linux/s390/kernel-features.h
> +++ b/sysdeps/unix/sysv/linux/s390/kernel-features.h
> @@ -50,3 +50,6 @@
>  
>  /* s390 only supports ipc syscall.  */
>  #undef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
> +
> +#undef __ASSUME_CLONE_DEFAULT
> +#define __ASSUME_CLONE_BACKWARDS2
> diff --git a/sysdeps/unix/sysv/linux/sh/arch-fork.h b/sysdeps/unix/sysv/linux/sh/arch-fork.h
> deleted file mode 100644
> index a29f61c..0000000
> --- a/sysdeps/unix/sysv/linux/sh/arch-fork.h
> +++ /dev/null
> @@ -1,28 +0,0 @@
> -/* ARCH_FORK definition for Linux fork implementation.  SH version.
> -   Copyright (C) 2003-2018 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
> -   <http://www.gnu.org/licenses/>.  */
> -
> -#include <sched.h>
> -#include <signal.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -/* TLS pointer argument is passed as the 5-th argument.  */
> -#define ARCH_FORK() \
> -  INLINE_SYSCALL (clone, 5,						      \
> -		  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD, 0,     \
> -		  NULL, &THREAD_SELF->tid, NULL)
> diff --git a/sysdeps/unix/sysv/linux/sparc/arch-fork.h b/sysdeps/unix/sysv/linux/sparc/arch-fork.h
> deleted file mode 100644
> index 03ccc9a..0000000
> --- a/sysdeps/unix/sysv/linux/sparc/arch-fork.h
> +++ /dev/null
> @@ -1,27 +0,0 @@
> -/* ARCH_FORK definition for Linux fork implementation.  SPARC version.
> -   Copyright (C) 2003-2018 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -   Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
> -
> -   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 <sched.h>
> -#include <signal.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -#define ARCH_FORK() \
> -  INLINE_CLONE_SYSCALL (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD, \
> -			0, NULL, NULL, &THREAD_SELF->tid)
> diff --git a/sysdeps/unix/sysv/linux/tile/arch-fork.h b/sysdeps/unix/sysv/linux/tile/arch-fork.h
> deleted file mode 100644
> index d0526d8..0000000
> --- a/sysdeps/unix/sysv/linux/tile/arch-fork.h
> +++ /dev/null
> @@ -1,29 +0,0 @@
> -/* ARCH_FORK definition for Linux fork implementation.  Tile* version.
> -   Copyright (C) 2011-2018 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
> -   Based on work contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
> -
> -   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 <sched.h>
> -#include <signal.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -#define ARCH_FORK() \
> -  INLINE_SYSCALL (clone, 4,						      \
> -		  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD,        \
> -		  0, NULL, &THREAD_SELF->tid)
> diff --git a/sysdeps/unix/sysv/linux/x86_64/arch-fork.h b/sysdeps/unix/sysv/linux/x86_64/arch-fork.h
> deleted file mode 100644
> index 4471970..0000000
> --- a/sysdeps/unix/sysv/linux/x86_64/arch-fork.h
> +++ /dev/null
> @@ -1,27 +0,0 @@
> -/* Internal definitions for thread-friendly fork implementation.  Linux/x86_64.
> -   Copyright (C) 2003-2018 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -   Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
> -
> -   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 <sched.h>
> -#include <sysdep.h>
> -#include <tls.h>
> -
> -#define ARCH_FORK() \
> -  INLINE_SYSCALL (clone, 4,                                                   \
> -                  CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD, 0,     \
> -                  NULL, &THREAD_SELF->tid)
> 


  parent reply	other threads:[~2018-03-07 16:49 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-07 13:09 [PATCH 1/3] Refactor Linux ARCH_FORK implementation Adhemerval Zanella
2018-02-07 13:09 ` [PATCH 2/3] dynarray: Implement remove function Adhemerval Zanella
2018-02-07 14:48   ` Alexander Monakov
2018-02-07 16:06     ` Adhemerval Zanella
2018-02-07 13:09 ` [PATCH 3/3] Refactor atfork handlers Adhemerval Zanella
2018-02-07 15:07   ` Florian Weimer
2018-02-07 17:16     ` Adhemerval Zanella
2018-02-08  8:32       ` Florian Weimer
2018-02-08 12:50         ` Adhemerval Zanella
2018-02-20 11:29           ` Florian Weimer
2018-02-20 13:00             ` Adhemerval Zanella
2018-02-20 13:05               ` Florian Weimer
2018-02-20 13:27                 ` Adhemerval Zanella
2018-02-20 13:42                   ` Florian Weimer
2018-02-20 13:48                     ` Adhemerval Zanella
2018-02-20 13:58                       ` Florian Weimer
2018-02-20 14:23                         ` Adhemerval Zanella
2018-02-23 10:41                           ` Florian Weimer
2018-02-23 12:10                             ` Adhemerval Zanella
2018-02-27  8:25                               ` Florian Weimer
2018-03-07 16:51 ` Adhemerval Zanella [this message]
2018-03-08 12:05 ` [PATCH 1/3] Refactor Linux ARCH_FORK implementation Florian Weimer
2018-03-08 12:58   ` Adhemerval Zanella

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: https://www.gnu.org/software/libc/involved.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=b7d456e7-3ffc-ae6c-a52a-c509218fb170@linaro.org \
    --to=adhemerval.zanella@linaro.org \
    --cc=libc-alpha@sourceware.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).