From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E90E9C07E99 for ; Mon, 12 Jul 2021 08:55:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE0DA60FF0 for ; Mon, 12 Jul 2021 08:55:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357258AbhGLI6g (ORCPT ); Mon, 12 Jul 2021 04:58:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:55108 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353841AbhGLIDC (ORCPT ); Mon, 12 Jul 2021 04:03:02 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 826CE61D0B; Mon, 12 Jul 2021 07:57:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626076666; bh=KPHrZ9ww3lJkGpMednQHili0mbC2nigYJEPPavNzF8M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EktdVFLK8PMmDYI5KZalVKoI0YzQ7wKGg1Tr9uv0ppBSdMgjOo1k/hjNp5iqiPvIW p8I6SToOIoh6cKpcskrZo04m6L4JswKTlxBX7iH9Id5N/9VcpwSQp2wWhXe97VoIyd 6Cq2ovvNtpX5j5fv+ACOikoRJWH1uvyLwwsgIOxQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Walle , Vignesh Raghavendra , Pratyush Yadav , Tudor Ambarus , Sasha Levin Subject: [PATCH 5.13 704/800] mtd: spi-nor: otp: return -EROFS if region is read-only Date: Mon, 12 Jul 2021 08:12:07 +0200 Message-Id: <20210712061041.672900696@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060912.995381202@linuxfoundation.org> References: <20210712060912.995381202@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michael Walle [ Upstream commit 388161ca45c911f566b71716bce5ff0119fb5522 ] SPI NOR flashes will just ignore program commands if the OTP region is locked. Thus, a user might not notice that the intended write didn't end up in the flash. Return -EROFS to the user in this case. From what I can tell, chips/cfi_cmdset_0001.c also return this error code. One could optimize spi_nor_mtd_otp_range_is_locked() to read the status register only once and not for every OTP region, but for that we would need some more invasive changes. Given that this is one-time-programmable memory and the normal access mode is reading, we just live with the small overhead. By moving the code around a bit, we can just check the length before calling spi_nor_mtd_otp_range_is_locked() and avoid an underflow there if a len is 0. This way we don't need to take the lock either. We also skip the "*retlen = 0" assignment, mtdcore already takes care of that for us. Fixes: 069089acf88b ("mtd: spi-nor: add OTP support") Signed-off-by: Michael Walle Signed-off-by: Vignesh Raghavendra Reviewed-by: Pratyush Yadav Reviewed-by: Tudor Ambarus Signed-off-by: Sasha Levin --- drivers/mtd/spi-nor/otp.c | 41 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 38 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c index 5c51a2c9be61..d8e68120a4b1 100644 --- a/drivers/mtd/spi-nor/otp.c +++ b/drivers/mtd/spi-nor/otp.c @@ -238,6 +238,29 @@ out: return ret; } +static int spi_nor_mtd_otp_range_is_locked(struct spi_nor *nor, loff_t ofs, + size_t len) +{ + const struct spi_nor_otp_ops *ops = nor->params->otp.ops; + unsigned int region; + int locked; + + /* + * If any of the affected OTP regions are locked the entire range is + * considered locked. + */ + for (region = spi_nor_otp_offset_to_region(nor, ofs); + region <= spi_nor_otp_offset_to_region(nor, ofs + len - 1); + region++) { + locked = ops->is_locked(nor, region); + /* take the branch it is locked or in case of an error */ + if (locked) + return locked; + } + + return 0; +} + static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs, size_t total_len, size_t *retlen, const u8 *buf, bool is_write) @@ -253,14 +276,26 @@ static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs, if (ofs < 0 || ofs >= spi_nor_otp_size(nor)) return 0; + /* don't access beyond the end */ + total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs); + + if (!total_len) + return 0; + ret = spi_nor_lock_and_prep(nor); if (ret) return ret; - /* don't access beyond the end */ - total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs); + if (is_write) { + ret = spi_nor_mtd_otp_range_is_locked(nor, ofs, total_len); + if (ret < 0) { + goto out; + } else if (ret) { + ret = -EROFS; + goto out; + } + } - *retlen = 0; while (total_len) { /* * The OTP regions are mapped into a contiguous area starting -- 2.30.2