linux-kernel - [PATCH 3.12 25/84] xtensa: fix threadptr reload on return to userspace

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Message-Id: <cc8fd3389247a99d4609af049ee2b958a84b6df5.1443792303.git.jslaby@suse.cz>
Date:	Fri,  2 Oct 2015 15:24:30 +0200
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Max Filippov <jcmvbkbc@...il.com>,
	Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 25/84] xtensa: fix threadptr reload on return to userspace

From: Max Filippov <jcmvbkbc@...il.com>

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

===============

commit 4229fb12a03e5da5882b420b0aa4a02e77447b86 upstream.

Userspace return code may skip restoring THREADPTR register if there are
no registers that need to be zeroed. This leads to spurious failures in
libc NPTL tests.

Always restore THREADPTR on return to userspace.

Signed-off-by: Max Filippov <jcmvbkbc@...il.com>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 arch/xtensa/kernel/entry.S | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 4b8e636e60da..900137e59b20 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -568,12 +568,13 @@ user_exception_exit:
 	 *	 (if we have restored WSBITS-1 frames).
 	 */
 
+2:
 #if XCHAL_HAVE_THREADPTR
 	l32i	a3, a1, PT_THREADPTR
 	wur	a3, threadptr
 #endif
 
-2:	j	common_exception_exit
+	j	common_exception_exit
 
 	/* This is the kernel exception exit.
 	 * We avoided to do a MOVSP when we entered the exception, but we
-- 
2.6.0

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