This patch is from the upstream release/2.20/master branch, which is a
backport containing only the syscalls.list changes in commit 016495b8 in
master.
commit adba20cf74bc6ea3910afe57d40ed755c92c2ddb
Author: Stefan Liebler <stli@linux.vnet.ibm.com>
Date: Thu Mar 3 08:24:18 2016 +0100
S390: Do not use direct socket syscalls if build on kernels >= 4.3. [BZ #19682]
Beginning with Linux 4.3, the kernel headers contain direct
system call numbers __NR_socket etc. on s390x. On older kernels,
the socket-multiplexer syscall __NR_socketcall was used.
To enable these new syscalls, the patch
"S390: Call direct system calls for socket operations."
(https://sourceware.org/git/?p=glibc.git;a=commit;h=016495b818cb61df7d0d10e6db54074271b3e3a5)
was applied upstream.
If glibc 2.23 is configured with --enable-kernel=4.3 and newer,
the direct socket syscalls are used.
For older kernels, the socket-multiplexer syscall is used instead.
In glibc 2.22 and earlier, this patch is not applied.
If you build glibc on a kernel < 4.3, the socket-multiplexer
syscall is used. But if you build glibc on kernel >= 4.3, the
direct socket-syscalls are used. If you install this glibc on a
kernel < 4.3, all socket operations will fail.
See "Bug 19682 - s390x: Incorrect syscall definitions cause
breakage with Linux 4.3 headers"
(https://sourceware.org/bugzilla/show_bug.cgi?id=19682)
The configure switch --enable-kernel does not influence this
behaviour on older glibc-releases.
The solution is to remove the direct socket-syscalls in
sysdeps/unix/sysv/linux/s390/s390-64/syscalls.list
(this patch) on older glibc-releases as it was done by the
upstream patch, too. These entries were never used on s390x,
but the c-files in sysdeps/unix/sysv/linux/.
After this removal, the behaviour of the socket functions are
not changed compared to the original glibc release version
and the socket-multiplexer-syscall is always used.
Index: b/sysdeps/unix/sysv/linux/s390/s390-64/syscalls.list
===================================================================
--- a/sysdeps/unix/sysv/linux/s390/s390-64/syscalls.list
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/syscalls.list
@@ -14,22 +14,3 @@ shmget - shmget i:iii __shmget shmget
semop - semop i:ipi __semop semop
semget - semget i:iii __semget semget
semctl - semctl i:iiii __semctl semctl
-
-# proper socket implementations:
-accept - accept Ci:iBN __libc_accept __accept accept
-bind - bind i:ipi __bind bind
-connect - connect Ci:ipi __libc_connect __connect connect
-getpeername - getpeername i:ipp __getpeername getpeername
-getsockname - getsockname i:ipp __getsockname getsockname
-getsockopt - getsockopt i:iiiBN __getsockopt getsockopt
-listen - listen i:ii __listen listen
-recv - recv Ci:ibni __libc_recv __recv recv
-recvfrom - recvfrom Ci:ibniBN __libc_recvfrom __recvfrom recvfrom
-recvmsg - recvmsg Ci:ipi __libc_recvmsg __recvmsg recvmsg
-send - send Ci:ibni __libc_send __send send
-sendmsg - sendmsg Ci:ipi __libc_sendmsg __sendmsg sendmsg
-sendto - sendto Ci:ibnibn __libc_sendto __sendto sendto
-setsockopt - setsockopt i:iiibn __setsockopt setsockopt
-shutdown - shutdown i:ii __shutdown shutdown
-socket - socket i:iii __socket socket
-socketpair - socketpair i:iiif __socketpair socketpair