powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM

commit 897bc3df8c5aebb54c32d831f917592e873d0559 upstream.

Commit e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint")
moved a code block around and this block uses a 'msr' variable outside of
the CONFIG_PPC_TRANSACTIONAL_MEM, however the 'msr' variable is declared
inside a CONFIG_PPC_TRANSACTIONAL_MEM block, causing a possible error when
CONFIG_PPC_TRANSACTION_MEM is not defined.

	error: 'msr' undeclared (first use in this function)

This is not causing a compilation error in the mainline kernel, because
'msr' is being used as an argument of MSR_TM_ACTIVE(), which is defined as
the following when CONFIG_PPC_TRANSACTIONAL_MEM is *not* set:

	#define MSR_TM_ACTIVE(x) 0

This patch just fixes this issue avoiding the 'msr' variable usage outside
the CONFIG_PPC_TRANSACTIONAL_MEM block, avoiding trusting in the
MSR_TM_ACTIVE() definition.

Cc: stable@vger.kernel.org
Reported-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Fixes: e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 6f70d1b4bf36e882b9bb17eac031bed0942da181..14b0f5b6a373da21f567c5e5cd4e27ca66430c4a 100644 (file)
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -755,11 +755,12 @@ SYSCALL_DEFINE0(rt_sigreturn)
                if (restore_tm_sigcontexts(current, &uc->uc_mcontext,
                                           &uc_transact->uc_mcontext))
                        goto badframe;
-       }
+       } else
 #endif
-       /* Fall through, for non-TM restore */
-       if (!MSR_TM_ACTIVE(msr)) {
+       {
                /*
+                * Fall through, for non-TM restore
+                *
                 * Unset MSR[TS] on the thread regs since MSR from user
                 * context does not have MSR active, and recheckpoint was
                 * not called since restore_tm_sigcontexts() was not called