linux-kernel - [PATCH 4.4 01/67] Revert: "powerpc/tm: Check for already reclaimed tasks"

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Message-Id: <20160509071837.316385222@linuxfoundation.org>
Date:	Mon,  9 May 2016 09:18:06 +0200
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Jiri Slaby <jslaby@...e.cz>,
	Michael Neuling <mikey@...ling.org>,
	Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 4.4 01/67] Revert: "powerpc/tm: Check for already reclaimed tasks"

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

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

This reverts commit e924c60db1b4891e45d15a33474ac5fab62cf029 which was
commit 7f821fc9c77a9b01fe7b1d6e72717b33d8d64142 upstream.

It shouldn't have been applied as the original was already in 4.4.

Reported-by: Jiri Slaby <jslaby@...e.cz>
Cc: Michael Neuling <mikey@...ling.org>
Cc: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/powerpc/kernel/process.c |   18 ------------------
 1 file changed, 18 deletions(-)

--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -569,24 +569,6 @@ static void tm_reclaim_thread(struct thr
 	if (!MSR_TM_SUSPENDED(mfmsr()))
 		return;
 
-	/*
-	 * Use the current MSR TM suspended bit to track if we have
-	 * checkpointed state outstanding.
-	 * On signal delivery, we'd normally reclaim the checkpointed
-	 * state to obtain stack pointer (see:get_tm_stackpointer()).
-	 * This will then directly return to userspace without going
-	 * through __switch_to(). However, if the stack frame is bad,
-	 * we need to exit this thread which calls __switch_to() which
-	 * will again attempt to reclaim the already saved tm state.
-	 * Hence we need to check that we've not already reclaimed
-	 * this state.
-	 * We do this using the current MSR, rather tracking it in
-	 * some specific thread_struct bit, as it has the additional
-	 * benifit of checking for a potential TM bad thing exception.
-	 */
-	if (!MSR_TM_SUSPENDED(mfmsr()))
-		return;
-
 	tm_reclaim(thr, thr->regs->msr, cause);
 
 	/* Having done the reclaim, we now have the checkpointed