Call exit directly in clone (BZ #21512)

On aarch64, alpha, arm, hppa, mips, nios2, powerpc, sh, sparc, tile,
and x86_64 the clone syscall jumps to _exit after the child execution
and the function ends the process execution by calling exit_group.
This behavior have a small issue where threads created with
CLONE_THREAD using clone syscall directly will eventually exit the
whole group altogether instead of just the thread created.  Also,
s390, microblaze, ia64, i386, and m68k differs by calling exit
syscall directly.

This patch changes all architectures to call the exit syscall
directly, as for s390, microblaze, ia64, i386, and m68k.  This do not
have change glibc internal behavior in any sort, since the only
usage of clone implementation in posix_spawn calls _exit directly
in the created child (fork uses a direct call to clone).

Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
powerpc-linux-gnu, powerpc64le-linux-gnu, sparc64-linux-gnu,
and sparcv9-linux-gnu.

	[BZ #21512]
	* sysdeps/unix/sysv/linux/aarch64/clone.S (__clone): Call exit
	syscall instead of jump to _exit.
	(CLONE_VM_BIT): Remove unused define.
	(CLONE_VM): Likewise.
	(CLONE_THREAD_BIT): Likewise.
	(CLONE_THREAD): Likewise.
	* sysdeps/unix/sysv/linux/alpha/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	* sysdeps/unix/sysv/linux/arm/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	(CLONE_THREAD): Likewise.
	* sysdeps/unix/sysv/linux/i386/clone.S (CLONE_VM): Likewise.
	* sysdeps/unix/sysv/linux/ia64/clone2.S (__clone2): Call exit
	syscall instead of jump to _exit.
	* sysdeps/unix/sysv/linux/hppa/clone.S (__clone): Likewise.
	* sysdeps/unix/sysv/linux/mips/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	(CLONE_THREAD): Likewise.
	* sysdeps/unix/sysv/linux/nios2/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S (__clone):
	Likewise.
	(CLONE_VM): Remove unused define.
	(CLONE_THREAD): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S (__clone):
	Likewise.
	(CLONE_VM): Remove unused define.
	(CLONE_THREAD): Likewise.
	* sysdeps/unix/sysv/linux/sh/clone.S  (__clone): Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	* sysdeps/unix/sysv/linux/sparc/sparc64/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	* sysdeps/unix/sysv/linux/tile/clone.S (__clone): Likewise.
	* sysdeps/unix/sysv/linux/x86_64/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	* sysdeps/unix/sysv/linux/Makefile (tests): Add tst-clone3.
	* sysdeps/unix/sysv/linux/tst-clone3.c: New file.

Fix

2 files changed, 3 insertions, 15 deletions

diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S b/sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S
index a07b7d3238..e48cc5f2f3 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S
@@ -20,10 +20,6 @@
 #define _ERRNO_H	1
 #include <bits/errno.h>
 
-#define CLONE_VM	0x00000100
-#define CLONE_THREAD	0x00010000
-
-
 /* This is the only really unusual system call in PPC linux, but not
    because of any weirdness in the system call itself; because of
    all the freaky stuff we have to do to make the call useful.  */
@@ -80,8 +76,7 @@ ENTRY (__clone)
 	mtctr	r30
 	mr	r3,r31
 	bctrl
-	/* Call _exit with result from procedure.  */
-	b	HIDDEN_JUMPTARGET(_exit)
+	DO_CALL(SYS_ify(exit))
 
 L(parent):
 	/* Parent.  Restore registers & return.  */
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
index 9e5bfd2d03..78c353a8c7 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
@@ -20,9 +20,6 @@
 #define _ERRNO_H	1
 #include <bits/errno.h>
 
-#define CLONE_VM	0x00000100
-#define CLONE_THREAD	0x00010000
-
 /* This is the only really unusual system call in PPC linux, but not
    because of any weirdness in the system call itself; because of
    all the freaky stuff we have to do to make the call useful.  */
@@ -84,15 +81,11 @@ ENTRY (__clone)
 	mr	r3,r31
 	bctrl
 	ld	r2,FRAME_TOC_SAVE(r1)
-	/* Call _exit with result from procedure.  */
-#ifdef SHARED
-	b	JUMPTARGET(__GI__exit)
-#else
-	bl	JUMPTARGET(_exit)
+
+	DO_CALL(SYS_ify(exit))
 	/* We won't ever get here but provide a nop so that the linker
 	   will insert a toc adjusting stub if necessary.  */
 	nop
-#endif
 
 L(badargs):
 	cfi_startproc