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Message-Id: <20190225125231.845656645@infradead.org>
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Date:   Mon, 25 Feb 2019 13:43:31 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com,
        julien.thierry@arm.com, will.deacon@arm.com, luto@amacapital.net,
        mingo@kernel.org, catalin.marinas@arm.com, james.morse@arm.com,
        valentin.schneider@arm.com, brgerst@gmail.com, jpoimboe@redhat.com,
        luto@kernel.org, bp@alien8.de, dvlasenk@redhat.com
Cc:     linux-kernel@vger.kernel.org, peterz@infradead.org
Subject: [PATCH 1/6] x86/uaccess: Dont evaluate argument inside AC region
References: <20190225124330.613028745@infradead.org>
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Sender: linux-kernel-owner@vger.kernel.org
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AC regions are special, make sure we don't do possibly complex
evaluations there.

Probably-Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/include/asm/uaccess.h |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -431,8 +431,10 @@ do {									\
 ({								\
 	__label__ __pu_label;					\
 	int __pu_err = -EFAULT;					\
+	__typeof__(*(ptr)) __pu_val;				\
+	__pu_val = x;						\
 	__uaccess_begin();					\
-	__put_user_size((x), (ptr), (size), __pu_label);	\
+	__put_user_size(__pu_val, (ptr), (size), __pu_label);	\
 	__pu_err = 0;						\
 __pu_label:							\
 	__uaccess_end();					\