ipc: rename old-style shmctl/semctl/msgctl syscalls

The behavior of these system calls is slightly different between
architectures, as determined by the CONFIG_ARCH_WANT_IPC_PARSE_VERSION
symbol. Most architectures that implement the split IPC syscalls don't set
that symbol and only get the modern version, but alpha, arm, microblaze,
mips-n32, mips-n64 and xtensa expect the caller to pass the IPC_64 flag.

For the architectures that so far only implement sys_ipc(), i.e. m68k,
mips-o32, powerpc, s390, sh, sparc, and x86-32, we want the new behavior
when adding the split syscalls, so we need to distinguish between the
two groups of architectures.

The method I picked for this distinction is to have a separate system call
entry point: sys_old_*ctl() now uses ipc_parse_version, while sys_*ctl()
does not. The system call tables of the five architectures are changed
accordingly.

As an additional benefit, we no longer need the configuration specific
definition for ipc_parse_version(), it always does the same thing now,
but simply won't get called on architectures with the modern interface.

A small downside is that on architectures that do set
ARCH_WANT_IPC_PARSE_VERSION, we now have an extra set of entry points
that are never called. They only add a few bytes of bloat, so it seems
better to keep them compared to adding yet another Kconfig symbol.
I considered adding new syscall numbers for the IPC_64 variants for
consistency, but decided against that for now.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 33 insertions, 7 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
index 0842411cb0e9..ce1ca9f7c6e9 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1137,16 +1137,15 @@ out_unlock1:
 	return err;
 }
 
-long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
+static long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf, int version)
 {
-	int err, version;
+	int err;
 	struct ipc_namespace *ns;
 	struct shmid64_ds sem64;
 
 	if (cmd < 0 || shmid < 0)
 		return -EINVAL;
 
-	version = ipc_parse_version(&cmd);
 	ns = current->nsproxy->ipc_ns;
 
 	switch (cmd) {
@@ -1194,8 +1193,22 @@ long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
 
 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
 {
-	return ksys_shmctl(shmid, cmd, buf);
+	return ksys_shmctl(shmid, cmd, buf, IPC_64);
+}
+
+#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
+long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
+{
+	int version = ipc_parse_version(&cmd);
+
+	return ksys_shmctl(shmid, cmd, buf, version);
+}
+
+SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
+{
+	return ksys_old_shmctl(shmid, cmd, buf);
 }
+#endif
 
 #ifdef CONFIG_COMPAT
 
@@ -1319,11 +1332,10 @@ static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
 	}
 }
 
-long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr)
+long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr, int version)
 {
 	struct ipc_namespace *ns;
 	struct shmid64_ds sem64;
-	int version = compat_ipc_parse_version(&cmd);
 	int err;
 
 	ns = current->nsproxy->ipc_ns;
@@ -1378,8 +1390,22 @@ long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr)
 
 COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
 {
-	return compat_ksys_shmctl(shmid, cmd, uptr);
+	return compat_ksys_shmctl(shmid, cmd, uptr, IPC_64);
 }
+
+#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
+long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr)
+{
+	int version = compat_ipc_parse_version(&cmd);
+
+	return compat_ksys_shmctl(shmid, cmd, uptr, version);
+}
+
+COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
+{
+	return compat_ksys_old_shmctl(shmid, cmd, uptr);
+}
+#endif
 #endif
 
 /*