S390: Call direct system calls for socket operations.

this patch calls direct system calls for socket operations in the same way as power does. The system calls were introduced in kernel commit https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=977108f89c989b1eeb5c8d938e1e71913391eb5f.
There are no direct recv, send, accept syscalls available on s390. Thus
recvfrom, sendto, accept4 are called instead of the socketcall by defining __ASSUME_*_FOR_*_SYSCALL macros. See recv.c, send.c, accept.c in sysdeps/unix/sysv/linux/ folder.

The socketcalls in syscalls.list for s390-64 are removed. They were never used on s390x.

ChangeLog:

	* sysdeps/unix/sysv/linux/s390/kernel-features.h:
	(__ASSUME_*_SYSCALL) Define new macros.
	* sysdeps/unix/sysv/linux/s390/s390-64/syscalls.list:
	Remove socketcall syscalls.
	* sysdeps/unix/sysv/linux/accept.c (__libc_accept):
	Use accept4 if defined __ASSUME_ACCEPT4_FOR_ACCEPT_SYSCALL.
	* sysdeps/unix/sysv/linux/recv.c (__libc_recv):
	Use recvfrom if defined __ASSUME_RECVFROM_FOR_RECV_SYSCALL.
	* sysdeps/unix/sysv/linux/send.c (__libc_send):
	Use sendto if defined __ASSUME_SENDTO_FOR_SEND_SYSCALL.

1 files changed, 2 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/send.c b/sysdeps/unix/sysv/linux/send.c
index d917e4d900..529c27d155 100644
--- a/sysdeps/unix/sysv/linux/send.c
+++ b/sysdeps/unix/sysv/linux/send.c
@@ -29,6 +29,8 @@ __libc_send (int fd, const void *buf, size_t len, int flags)
 {
 #ifdef __ASSUME_SEND_SYSCALL
   return SYSCALL_CANCEL (send, fd, buf, len, flags);
+#elif defined __ASSUME_SENDTO_FOR_SEND_SYSCALL
+  return SYSCALL_CANCEL (sendto, fd, buf, len, flags, NULL, 0);
 #else
   return SOCKETCALL_CANCEL (send, fd, buf, len, flags);
 #endif