[S390] ipc: call generic sys_ipc demultiplexer

Call generic IPC demultiplexer instead of having a nearly identical
s390 variant. Also make sure that native and compat handling now have
the same behaviour.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/unistd.h

@@ -398,6 +398,7 @@
 #define __ARCH_WANT_SYS_SIGNAL
 #define __ARCH_WANT_SYS_UTIME
 #define __ARCH_WANT_SYS_SOCKETCALL
+#define __ARCH_WANT_SYS_IPC
 #define __ARCH_WANT_SYS_FADVISE64
 #define __ARCH_WANT_SYS_GETPGRP
 #define __ARCH_WANT_SYS_LLSEEK

arch/s390/kernel/compat_linux.c

@@ -278,9 +278,6 @@ asmlinkage long sys32_ipc(u32 call, int first, int second, int third, u32 ptr)
 {
 	if (call >> 16)		/* hack for backward compatibility */
 		return -EINVAL;
-
-	call &= 0xffff;
-
 	switch (call) {
 	case SEMTIMEDOP:
 		return compat_sys_semtimedop(first, compat_ptr(ptr),

arch/s390/kernel/sys_s390.c

@@ -60,74 +60,22 @@ SYSCALL_DEFINE1(mmap2, struct s390_mmap_arg_struct __user *, arg)
 }
 
 /*
- * sys_ipc() is the de-multiplexer for the SysV IPC calls..
- *
- * This is really horribly ugly.
+ * sys_ipc() is the de-multiplexer for the SysV IPC calls.
  */
 SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, unsigned long, second,
 		unsigned long, third, void __user *, ptr)
 {
-        struct ipc_kludge tmp;
-	int ret;
-
-        switch (call) {
-        case SEMOP:
-		return sys_semtimedop(first, (struct sembuf __user *)ptr,
-				       (unsigned)second, NULL);
-	case SEMTIMEDOP:
-		return sys_semtimedop(first, (struct sembuf __user *)ptr,
-				       (unsigned)second,
-				       (const struct timespec __user *) third);
-        case SEMGET:
-                return sys_semget(first, (int)second, third);
-        case SEMCTL: {
-                union semun fourth;
-                if (!ptr)
-                        return -EINVAL;
-                if (get_user(fourth.__pad, (void __user * __user *) ptr))
-                        return -EFAULT;
-                return sys_semctl(first, (int)second, third, fourth);
-        }
-        case MSGSND:
-		return sys_msgsnd (first, (struct msgbuf __user *) ptr,
-                                   (size_t)second, third);
-		break;
-        case MSGRCV:
-                if (!ptr)
-                        return -EINVAL;
-                if (copy_from_user (&tmp, (struct ipc_kludge __user *) ptr,
-                                    sizeof (struct ipc_kludge)))
-                        return -EFAULT;
-                return sys_msgrcv (first, tmp.msgp,
-                                   (size_t)second, tmp.msgtyp, third);
-        case MSGGET:
-                return sys_msgget((key_t)first, (int)second);
-        case MSGCTL:
-                return sys_msgctl(first, (int)second,
-				   (struct msqid_ds __user *)ptr);
-
-	case SHMAT: {
-		ulong raddr;
-		ret = do_shmat(first, (char __user *)ptr,
-				(int)second, &raddr);
-		if (ret)
-			return ret;
-		return put_user (raddr, (ulong __user *) third);
-		break;
-        }
-	case SHMDT:
-		return sys_shmdt ((char __user *)ptr);
-	case SHMGET:
-		return sys_shmget(first, (size_t)second, third);
-	case SHMCTL:
-		return sys_shmctl(first, (int)second,
-                                   (struct shmid_ds __user *) ptr);
-	default:
-		return -ENOSYS;
-
-	}
-
-	return -EINVAL;
+	if (call >> 16)
+		return -EINVAL;
+	/* The s390 sys_ipc variant has only five parameters instead of six
+	 * like the generic variant. The only difference is the handling of
+	 * the SEMTIMEDOP subcall where on s390 the third parameter is used
+	 * as a pointer to a struct timespec where the generic variant uses
+	 * the fifth parameter.
+	 * Therefore we can call the generic variant by simply passing the
+	 * third parameter also as fifth parameter.
+	 */
+	return sys_ipc(call, first, second, third, ptr, third);
 }
 
 #ifdef CONFIG_64BIT