linux-kernel - [PATCH] spi: dw: fix potential variable assignment error

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20181228083312.14928-1-shol@livemail.tw>
Date:   Fri, 28 Dec 2018 16:33:12 +0800
From:   shaftarger <sholchen@...il.com>
To:     Mark Brown <broonie@...nel.org>, linux-spi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     shaftarger <shol@...email.tw>
Subject: [PATCH] spi: dw: fix potential variable assignment error

spi::mode is defined by framework for several SPI capabilities,
such as polarity, phase, bit-endian, wire number. Directly use this
variable for setting controller's polarity and phase causes other
bit in register being set. Since SPI framework has its definition,
SPI_CPOL and SPI_CPHA offset may be changed by framwork change.
Instead of just mask off the relevant bits,
fetch required bit in spi::mode and set to register.

Signed-off-by: shaftarger <shol@...email.tw>
---
 drivers/spi/spi-dw.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
index b705f2bdb8b9..1c4cb6e8c5a1 100644
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -317,7 +317,8 @@ static int dw_spi_transfer_one(struct spi_controller *master,
 	/* Default SPI mode is SCPOL = 0, SCPH = 0 */
 	cr0 = (transfer->bits_per_word - 1)
 		| (chip->type << SPI_FRF_OFFSET)
-		| (spi->mode << SPI_MODE_OFFSET)
+		| ((((spi->mode & SPI_CPOL) ? 1 : 0) << SPI_SCOL_OFFSET) |
+			(((spi->mode & SPI_CPHA) ? 1 : 0) << SPI_SCPH_OFFSET))
 		| (chip->tmode << SPI_TMOD_OFFSET);
 
 	/*
-- 
2.12.2.windows.2