linux-kernel - [PATCH] powerpc: fix personality handling in ppc64

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Date:	Wed, 1 Aug 2012 22:03:42 +0200 (CEST)
From:	Jiri Kosina <jkosina@...e.cz>
To:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>
Cc:	linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH] powerpc: fix personality handling in ppc64_personality()

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

Use personality() macro to compare only PER_MASK bytes and make sure that
we are setting only the bits that should be set, instead of
overwriting the whole value.

Signed-off-by: Jiri Kosina <jkosina@...e.cz>
---

Found accidentally. Untested, I don't have the hardware.

 arch/powerpc/kernel/syscalls.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/syscalls.c b/arch/powerpc/kernel/syscalls.c
index f2496f2..4dcc7c6 100644
--- a/arch/powerpc/kernel/syscalls.c
+++ b/arch/powerpc/kernel/syscalls.c
@@ -107,11 +107,11 @@ long ppc64_personality(unsigned long personality)
 	long ret;
 
 	if (personality(current->personality) == PER_LINUX32
-	    && personality == PER_LINUX)
-		personality = PER_LINUX32;
+	    && personality(personality) == PER_LINUX)
+		personality &= ~PER_LINUX | PER_LINUX32;
 	ret = sys_personality(personality);
-	if (ret == PER_LINUX32)
-		ret = PER_LINUX;
+	if (personality(ret) == PER_LINUX32)
+		ret &= ~PER_LINUX32 | PER_LINUX;
 	return ret;
 }
 #endif

-- 
Jiri Kosina
SUSE Labs
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