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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>,
        Michal Simek <michal.simek@xilinx.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 081/113] microblaze: Prevent the overflow of the start
Date:   Thu, 27 Feb 2020 14:36:37 +0100
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From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>

[ Upstream commit 061d2c1d593076424c910cb1b64ecdb5c9a6923f ]

In case the start + cache size is more than the max int the
start overflows.
Prevent the same.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/microblaze/kernel/cpu/cache.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/microblaze/kernel/cpu/cache.c b/arch/microblaze/kernel/cpu/cache.c
index 0bde47e4fa694..dcba53803fa5f 100644
--- a/arch/microblaze/kernel/cpu/cache.c
+++ b/arch/microblaze/kernel/cpu/cache.c
@@ -92,7 +92,8 @@ static inline void __disable_dcache_nomsr(void)
 #define CACHE_LOOP_LIMITS(start, end, cache_line_length, cache_size)	\
 do {									\
 	int align = ~(cache_line_length - 1);				\
-	end = min(start + cache_size, end);				\
+	if (start <  UINT_MAX - cache_size)				\
+		end = min(start + cache_size, end);			\
 	start &= align;							\
 } while (0)
 
-- 
2.20.1