sparc64: do not clobber personality flags in sys_sparc64_personality()

There are multiple errors in how sys_sparc64_personality() handles
personality flags stored in top three bytes.

- directly comparing current->personality against PER_LINUX32 doesn't work
  in cases when any of the personality flags stored in the top three bytes
  are used.
- directly forcefully setting personality to PER_LINUX32 or PER_LINUX
  discards any flags stored in the top three bytes

Fix the first one by properly using personality() macro to compare only
PER_MASK bytes.
Fix the second one by setting only the bits that should be set, instead of
overwriting the whole value.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 5 deletions

diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 0dc1f5786081..11c6c9603e71 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -502,12 +502,12 @@ SYSCALL_DEFINE1(sparc64_personality, unsigned long, personality)
 {
         int ret;
 
-        if (current->personality == PER_LINUX32 &&
-            personality == PER_LINUX)
-                personality = PER_LINUX32;
+        if (personality(current->personality) == PER_LINUX32 &&
+            personality(personality) == PER_LINUX)
+                personality |= PER_LINUX32;
         ret = sys_personality(personality);
-        if (ret == PER_LINUX32)
-                ret = PER_LINUX;
+        if (personality(ret) == PER_LINUX32)
+                ret &= ~PER_LINUX32;
 
         return ret;
 }