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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,
        Nicolas VINCENT <nicolas.vincent@vossloh.com>,
        Jochen Friedrich <jochen@scram.de>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Wolfram Sang <wsa@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 28/38] i2c: cpm: Fix i2c_ram structure
Date:   Mon,  5 Oct 2020 17:26:45 +0200
Message-Id: <20201005142110.026985868@linuxfoundation.org>
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From: Nicolas VINCENT <nicolas.vincent@vossloh.com>

[ Upstream commit a2bd970aa62f2f7f80fd0d212b1d4ccea5df4aed ]

the i2c_ram structure is missing the sdmatmp field mentionned in
datasheet for MPC8272 at paragraph 36.5. With this field missing, the
hardware would write past the allocated memory done through
cpm_muram_alloc for the i2c_ram structure and land in memory allocated
for the buffers descriptors corrupting the cbd_bufaddr field. Since this
field is only set during setup(), the first i2c transaction would work
and the following would send data read from an arbitrary memory
location.

Fixes: 61045dbe9d8d ("i2c: Add support for I2C bus on Freescale CPM1/CPM2 controllers")
Signed-off-by: Nicolas VINCENT <nicolas.vincent@vossloh.com>
Acked-by: Jochen Friedrich <jochen@scram.de>
Acked-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-cpm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/busses/i2c-cpm.c b/drivers/i2c/busses/i2c-cpm.c
index 8a8ca945561b0..7eba874a981d3 100644
--- a/drivers/i2c/busses/i2c-cpm.c
+++ b/drivers/i2c/busses/i2c-cpm.c
@@ -74,6 +74,9 @@ struct i2c_ram {
 	char    res1[4];	/* Reserved */
 	ushort  rpbase;		/* Relocation pointer */
 	char    res2[2];	/* Reserved */
+	/* The following elements are only for CPM2 */
+	char    res3[4];	/* Reserved */
+	uint    sdmatmp;	/* Internal */
 };
 
 #define I2COM_START	0x80
-- 
2.25.1