From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3897A8BE0 for ; Tue, 28 Mar 2023 14:47:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3EC7C433D2; Tue, 28 Mar 2023 14:47:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1680014829; bh=RNFwa18Oo4RwKvSJdNGd4MX+4jvZTzgq3AWMHP9L8ys=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yejGpg8yQzed7D/pIZn83GwV8mfjE3Mb02x0SCow246+Xd3C5UiOwdfn7NKcSS/PU +fUcQ1ZbLVWpjEAhX0RKJRoLZJ1GRapKYHtQhUbXdbK0YX82DskrpyBlrALXBatv6E cg3226/bpMxxpQ+P3pEvKTMZr5UzWaPhCnC+/m9Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Matthias Schiffer , Wolfram Sang , Sasha Levin Subject: [PATCH 6.2 037/240] i2c: mxs: ensure that DMA buffers are safe for DMA Date: Tue, 28 Mar 2023 16:40:00 +0200 Message-Id: <20230328142621.149491299@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230328142619.643313678@linuxfoundation.org> References: <20230328142619.643313678@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Matthias Schiffer [ Upstream commit 5190417bdf72c71b65bd9892103c6186816a6e8b ] We found that after commit 9c46929e7989 ("ARM: implement THREAD_INFO_IN_TASK for uniprocessor systems"), the PCF85063 RTC driver stopped working on i.MX28 due to regmap_bulk_read() reading bogus data into a stack buffer. This is caused by the i2c-mxs driver using DMA transfers even for messages without the I2C_M_DMA_SAFE flag, and the aforementioned commit enabling vmapped stacks. As the MXS I2C controller requires DMA for reads of >4 bytes, DMA can't be disabled, so the issue is fixed by using i2c_get_dma_safe_msg_buf() to create a bounce buffer when needed. Fixes: 9c46929e7989 ("ARM: implement THREAD_INFO_IN_TASK for uniprocessor systems") Signed-off-by: Matthias Schiffer Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-mxs.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c index d113bed795452..e0f3b3545cfe4 100644 --- a/drivers/i2c/busses/i2c-mxs.c +++ b/drivers/i2c/busses/i2c-mxs.c @@ -171,7 +171,7 @@ static void mxs_i2c_dma_irq_callback(void *param) } static int mxs_i2c_dma_setup_xfer(struct i2c_adapter *adap, - struct i2c_msg *msg, uint32_t flags) + struct i2c_msg *msg, u8 *buf, uint32_t flags) { struct dma_async_tx_descriptor *desc; struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap); @@ -226,7 +226,7 @@ static int mxs_i2c_dma_setup_xfer(struct i2c_adapter *adap, } /* Queue the DMA data transfer. */ - sg_init_one(&i2c->sg_io[1], msg->buf, msg->len); + sg_init_one(&i2c->sg_io[1], buf, msg->len); dma_map_sg(i2c->dev, &i2c->sg_io[1], 1, DMA_FROM_DEVICE); desc = dmaengine_prep_slave_sg(i2c->dmach, &i2c->sg_io[1], 1, DMA_DEV_TO_MEM, @@ -259,7 +259,7 @@ static int mxs_i2c_dma_setup_xfer(struct i2c_adapter *adap, /* Queue the DMA data transfer. */ sg_init_table(i2c->sg_io, 2); sg_set_buf(&i2c->sg_io[0], &i2c->addr_data, 1); - sg_set_buf(&i2c->sg_io[1], msg->buf, msg->len); + sg_set_buf(&i2c->sg_io[1], buf, msg->len); dma_map_sg(i2c->dev, i2c->sg_io, 2, DMA_TO_DEVICE); desc = dmaengine_prep_slave_sg(i2c->dmach, i2c->sg_io, 2, DMA_MEM_TO_DEV, @@ -563,6 +563,7 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap); int ret; int flags; + u8 *dma_buf; int use_pio = 0; unsigned long time_left; @@ -588,13 +589,20 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, if (ret && (ret != -ENXIO)) mxs_i2c_reset(i2c); } else { + dma_buf = i2c_get_dma_safe_msg_buf(msg, 1); + if (!dma_buf) + return -ENOMEM; + reinit_completion(&i2c->cmd_complete); - ret = mxs_i2c_dma_setup_xfer(adap, msg, flags); - if (ret) + ret = mxs_i2c_dma_setup_xfer(adap, msg, dma_buf, flags); + if (ret) { + i2c_put_dma_safe_msg_buf(dma_buf, msg, false); return ret; + } time_left = wait_for_completion_timeout(&i2c->cmd_complete, msecs_to_jiffies(1000)); + i2c_put_dma_safe_msg_buf(dma_buf, msg, true); if (!time_left) goto timeout; -- 2.39.2