sparc64: do not clobber personality flags in sys_sparc64_personality()

[ Upstream commit a27032eee8cb6e16516f13c8a9752e9d5d4cc430 ]

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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 441521a..5e4252b 100644 (file)
--- 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;
 }