[PATCH 3.16.y-ckt 007/133] xtensa: fix threadptr reload on return to userspace

From: Luis Henriques
Date: Wed Sep 30 2015 - 06:41:03 EST

3.16.7-ckt18 -stable review patch. If anyone has any objections, please let me know.


From: Max Filippov <jcmvbkbc@xxxxxxxxx>

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@xxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
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 a06b7efaae82..8a749f02d8d6 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).

l32i a3, a1, PT_THREADPTR
wur a3, threadptr

-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
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