ipc: introduce ksys_ipc()/compat_ksys_ipc() for s390

The sys_ipc() and compat_ksys_ipc() functions are meant to only
be used from the system call table, not called by another function.

Introduce ksys_*() interfaces for this purpose, as we have done
for many other system calls.

Link: https://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnd Bergmann <[e-mail]>
Reviewed-by: Heiko Carstens <[e-mail]>
[[e-mail]: compile fix for !CONFIG_COMPAT]
Signed-off-by: Heiko Carstens <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/kernel/compat_linux.c

···
 {
 	if (call >> 16)		/* hack for backward compatibility */
 		return -EINVAL;
-	return compat_sys_ipc(call, first, second, third, ptr, third);
+	return compat_ksys_ipc(call, first, second, third, ptr, third);
 }
 #endif
 

arch/s390/kernel/sys_s390.c

···
 	return error;
 }
 
+#ifdef CONFIG_SYSVIPC
 /*
  * sys_ipc() is the de-multiplexer for the SysV IPC calls.
  */
···
 	 * 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);
+	return ksys_ipc(call, first, second, third, ptr, third);
 }
+#endif /* CONFIG_SYSVIPC */
 
 SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
 {

include/linux/syscalls.h

···
 			      unsigned long prot, unsigned long flags,
 			      unsigned long fd, unsigned long pgoff);
 ssize_t ksys_readahead(int fd, loff_t offset, size_t count);
+int ksys_ipc(unsigned int call, int first, unsigned long second,
+	unsigned long third, void __user * ptr, long fifth);
+int compat_ksys_ipc(u32 call, int first, int second,
+	u32 third, u32 ptr, u32 fifth);
 
 /*
  * The following kernel syscall equivalents are just wrappers to fs-internal

ipc/syscall.c

···
 #include <linux/shm.h>
 #include <linux/uaccess.h>
 
-SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
-		unsigned long, third, void __user *, ptr, long, fifth)
+int ksys_ipc(unsigned int call, int first, unsigned long second,
+	unsigned long third, void __user * ptr, long fifth)
 {
 	int version, ret;
 
···
 		return -ENOSYS;
 	}
 }
+
+SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
+		unsigned long, third, void __user *, ptr, long, fifth)
+{
+	return ksys_ipc(call, first, second, third, ptr, fifth);
+}
 #endif
 
 #ifdef CONFIG_COMPAT
···
 };
 
 #ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
-COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second,
-	u32, third, compat_uptr_t, ptr, u32, fifth)
+int compat_ksys_ipc(u32 call, int first, int second,
+	u32 third, compat_uptr_t ptr, u32 fifth)
 {
 	int version;
 	u32 pad;
···
 	}
 
 	return -ENOSYS;
+}
+
+COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second,
+	u32, third, compat_uptr_t, ptr, u32, fifth)
+{
+	return compat_ksys_ipc(call, first, second, third, ptr, fifth);
 }
 #endif
 #endif

kernel/sys_ni.c

···
 /* s390 */
 COND_SYSCALL(s390_pci_mmio_read);
 COND_SYSCALL(s390_pci_mmio_write);
+COND_SYSCALL(s390_ipc);
 COND_SYSCALL_COMPAT(s390_ipc);
 
 /* powerpc */