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From: Breno Leitao <leitao@debian.org>
To: linuxppc-dev@lists.ozlabs.org
Cc: mikey@neuling.org, mpe@ellerman.id.au,
	gregkh@linuxfoundation.org, stable@vger.kernel.org,
	Breno Leitao <leitao@debian.org>
Subject: [PATCH] powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM
Date: Wed,  9 Jan 2019 11:16:45 -0200	[thread overview]
Message-ID: <1547039805-7979-1-git-send-email-leitao@debian.org> (raw)

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>
---

NB: Since stable kernels didn't cherry picked 5c784c8414fba ('powerpc/tm:
Remove msr_tm_active()), MSR_TM_ACTIVE() is not defined as 0 for
CONFIG_PPC_TRANSACTIONAL_MEM=n case, thus triggering the compilation error
above.

Tested against stable kernel 4.19.13-rc2 and problem is now fixed when
CONFIG_PPC_TRANSACTIONAL_MEM=n

 arch/powerpc/kernel/signal_64.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index daa28cb72272..8fe698162ab9 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -739,11 +739,12 @@ 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
-- 
2.19.0


WARNING: multiple messages have this Message-ID (diff)
From: Breno Leitao <leitao@debian.org>
To: linuxppc-dev@lists.ozlabs.org
Cc: Breno Leitao <leitao@debian.org>,
	mikey@neuling.org, stable@vger.kernel.org,
	gregkh@linuxfoundation.org
Subject: [PATCH] powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM
Date: Wed,  9 Jan 2019 11:16:45 -0200	[thread overview]
Message-ID: <1547039805-7979-1-git-send-email-leitao@debian.org> (raw)

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>
---

NB: Since stable kernels didn't cherry picked 5c784c8414fba ('powerpc/tm:
Remove msr_tm_active()), MSR_TM_ACTIVE() is not defined as 0 for
CONFIG_PPC_TRANSACTIONAL_MEM=n case, thus triggering the compilation error
above.

Tested against stable kernel 4.19.13-rc2 and problem is now fixed when
CONFIG_PPC_TRANSACTIONAL_MEM=n

 arch/powerpc/kernel/signal_64.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index daa28cb72272..8fe698162ab9 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -739,11 +739,12 @@ 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
-- 
2.19.0


             reply	other threads:[~2019-01-09 13:16 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-09 13:16 Breno Leitao [this message]
2019-01-09 13:16 ` [PATCH] powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM Breno Leitao
2019-01-14 10:12 ` Michael Ellerman
2019-01-14 10:12   ` Michael Ellerman
2019-01-16 13:35 ` [PATCH] " Sasha Levin
2019-01-17 11:49   ` Breno Leitao
2019-01-17 11:49     ` Breno Leitao
2019-01-18 14:51     ` Sasha Levin
2019-01-18 14:51       ` Sasha Levin

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