[SPARC64]: Fix bugs in SYSV IPC handling in 64-bit processes.

Thanks to Tom Callaway for the excellent bug report and
test case.

sys_ipc() has several problems, most to due with semaphore
call handling:

1) 'err' return should be a 'long'
2) "union semun" is passed in a register on 64-bit compared
   to 32-bit which provides it on the stack and therefore
   by reference
3) Second and third arguments to SEMCTL are swapped compared
   to 32-bit.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 11 deletions

diff --git a/arch/sparc64/kernel/sys_sparc.c b/arch/sparc64/kernel/sys_sparc.c
index d108eeb0734f..0d5c50264945 100644
--- a/arch/sparc64/kernel/sys_sparc.c
+++ b/arch/sparc64/kernel/sys_sparc.c
@@ -436,7 +436,7 @@ out:
 asmlinkage long sys_ipc(unsigned int call, int first, unsigned long second,
                         unsigned long third, void __user *ptr, long fifth)
 {
-        int err;
+        long err;
 
         /* No need for backward compatibility. We can start fresh... */
         if (call <= SEMCTL) {
@@ -453,16 +453,9 @@ asmlinkage long sys_ipc(unsigned int call, int first, unsigned long second,
                         err = sys_semget(first, (int)second, (int)third);
                         goto out;
                 case SEMCTL: {
-                        union semun fourth;
-                        err = -EINVAL;
-                        if (!ptr)
-                                goto out;
-                        err = -EFAULT;
-                        if (get_user(fourth.__pad,
-                                     (void __user * __user *) ptr))
-                                goto out;
-                        err = sys_semctl(first, (int)second | IPC_64,
-                                         (int)third, fourth);
+                        err = sys_semctl(first, third,
+                                         (int)second | IPC_64,
+                                         (union semun) ptr);
                         goto out;
                 }
                 default: