[PATCH 171/241] sparc64: do not clobber personality flags in sys_sparc64_personality()

[Herton Ronaldo Krzesinski]

3.5.7.2 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jiri Kosina <jkosina at suse.cz>

commit a27032eee8cb6e16516f13c8a9752e9d5d4cc430 upstream.

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 at suse.cz>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 arch/sparc/kernel/sys_sparc_64.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 275f74f..3c38914 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -519,12 +519,12 @@ 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;
 }
-- 
1.7.9.5