From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753232AbdLKOIA (ORCPT ); Mon, 11 Dec 2017 09:08:00 -0500 Received: from mailout2.w1.samsung.com ([210.118.77.12]:33147 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752938AbdLKOGn (ORCPT ); Mon, 11 Dec 2017 09:06:43 -0500 DKIM-Filter: OpenDKIM Filter v2.11.0 mailout2.w1.samsung.com 20171211140640euoutp0258f7aa4849b6dbdca7d1c06d0f864d08~-QpN4FjR70716707167euoutp02V X-AuditID: cbfec7f5-f79d06d0000031c7-28-5a2e90ef9237 MIME-version: 1.0 Content-transfer-encoding: 8BIT Content-type: text/plain; charset="UTF-8" From: =?UTF-8?q?=C5=81ukasz=20Stelmach?= To: Krzysztof Kozlowski , robh+dt@kernel.org, Stephan Mueller , Herbert Xu , "David S . Miller" , Kukjin Kim , linux-crypto@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org Cc: =?UTF-8?q?=C5=81ukasz=20Stelmach?= , Marek Szyprowski , Bartlomiej Zolnierkiewicz Subject: [PATCH v2 4/4] crypto: exynos - Introduce mutex to prevent concurrent access to hardware Date: Mon, 11 Dec 2017 15:06:23 +0100 Message-id: <20171211140623.7673-5-l.stelmach@samsung.com> X-Mailer: git-send-email 2.11.0 In-reply-to: <20171211140623.7673-1-l.stelmach@samsung.com> In-reply-to: <20171205123558.31087-1-l.stelmach@samsung.com> Organization: Samsung R&D Institute Poland X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrFKsWRmVeSWpSXmKPExsWy7djPc7rvJ+hFGRz8bGCxccZ6Vos551tY LLpfyVj0P37NbHH+/AZ2i5uHVjBa3L/3k8ni8q45bBYzzu9jslh75C67ReveI+wWU0+vZXHg 8fh05QqTx5aVN5k8th1Q9di0qpPNo2/LKkaPz5vkAtiiuGxSUnMyy1KL9O0SuDLWN/9iL5go VfHu5S+WBsbVol2MnBwSAiYSU+YvZoSwxSQu3FvP1sXIxSEksJRR4vTLr6wQzmdGiY0XHrB0 MXKAdfybmw8RX8Yoce/1TTaQbl4BQYkfk++B1TALyEscuZQNEmYW0JTYuns9O0T9F0aJgx++ M4Ek2AQcJfqXngBbICKwj0ni8cSpjCAOM8jUg9tOgk0VFkiWaFnTBHYfi4CqxMF1i5ghtllJ dBxYyAZxt7zErraLrCA2p4C1ROfxdjYI20Zi4dkZYDa/gJbEmqbrLCALJATmsUs0PD3PBNHs InHkfiM7hC0s8er4FihbRqKz4yATREM/o8Th+d+hElMYJRYvdICwrSX+rJrIBvEon8SkbdOZ IWHEK9HRJgRR4iHxufUZM4TtKLGu+TIjJCz6GCVOfPzLMoFRYRZS8M1CBN8spOBbwMi8ilEk tbQ4Nz212FSvODG3uDQvXS85P3cTIzBFnf53/OsOxqXHrA4xCnAwKvHwcvTqRQmxJpYVV+Ye YpTgYFYS4TX1040S4k1JrKxKLcqPLyrNSS0+xCjNwaIkzmsb1RYpJJCeWJKanZpakFoEk2Xi 4JRqYHQ6qhv4LS3oqLO2htjbmPVhj3aekl80fUlnZQ8Hw4UKGa2UCWtdF+fFz/z4c19Z5cyN UxKfXIu3rbsUuzJNRu2dwmmXnC1H63Z1PeAtOKUyryuoJLn/6ZvTbOs/82Z4Z5onfU45YH+8 cOVfGfnyRz/1qnb8NHv85OmD/ZJaCQ4Tu/l6fl2bv0WJpTgj0VCLuag4EQB21C1iTQMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprJIsWRmVeSWpSXmKPExsVy+t/xq7rvJ+hFGazq4rbYOGM9q8Wc8y0s Ft2vZCz6H79mtjh/fgO7xc1DKxgt7t/7yWRxedccNosZ5/cxWaw9cpfdonXvEXaLqafXsjjw eHy6coXJY8vKm0we2w6oemxa1cnm0bdlFaPH501yAWxRXDYpqTmZZalF+nYJXBnrm3+xF0yU qnj38hdLA+Nq0S5GDg4JAROJf3Pzuxg5gUwxiQv31rN1MXJxCAksYZT4e/A/G0iCV0BQ4sfk eywg9cwC8hJHLmWDhJkF1CUmzVvEDFH/jVHide89RpAEm4CjRP/SE6wgCRGBA0wSDT1LwKYy CyxjlPjT0wo2VVggWeLnjG1gNouAqsTBdSCjQLZZSXQcWMgGcZK8xK62i6wgNqeAtUTn8Xaw uBBQzfrf69gh4jYSC8/OYAO5Tgio5vTkaJAwv4CWxJqm6ywTGIVnIflhFsIPs5D8sICReRWj SGppcW56brGhXnFibnFpXrpecn7uJkZghG079nPzDsZLG4MPMQpwMCrx8G7o0osSYk0sK67M PcQowcGsJMJr6qcbJcSbklhZlVqUH19UmpNafIhRmoNFSZy3d8/qSCGB9MSS1OzU1ILUIpgs EwenVAOjhPE0x9lXZjjPPeGQfLaAPc9YKZtjB98Uztw/Yb2mPA5T/1RWrQ17NU989r6vKl9/ nt38+sqsQwFtqfcDdp6pSD+/eff9H62buadzrTvreo/n+F4/aVON1yGz/l7eP/P/3r+n7Zuv bH/ZxPr20UPtRbEabQGHLtXFftG2FPzx7mPY8nM31yZtEVViKc5INNRiLipOBADjKJoXrAIA AA== X-CMS-MailID: 20171211140639eucas1p23232610e264416b74fa4e69c14d85968 X-Msg-Generator: CA CMS-TYPE: 201P X-CMS-RootMailID: 20171211140639eucas1p23232610e264416b74fa4e69c14d85968 X-RootMTR: 20171211140639eucas1p23232610e264416b74fa4e69c14d85968 References: <20171211140623.7673-1-l.stelmach@samsung.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Cc: Marek Szyprowski , Bartlomiej Zolnierkiewicz Hardware operations like reading random numbers and setting a seed need to be conducted in a single thread. Therefore a mutex is required to prevent multiple threads (processes) from accessing the hardware at the same time. The sequence of mutex_lock() and mutex_unlock() in the exynos_rng_reseed() function enables switching between different threads waiting for the driver to generate random numbers for them. Signed-off-by: Łukasz Stelmach --- drivers/crypto/exynos-rng.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/crypto/exynos-rng.c b/drivers/crypto/exynos-rng.c index c72a838f1932..6209035ca659 100644 --- a/drivers/crypto/exynos-rng.c +++ b/drivers/crypto/exynos-rng.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -79,6 +80,7 @@ struct exynos_rng_dev { enum exynos_prng_type type; void __iomem *mem; struct clk *clk; + struct mutex lock; /* Generated numbers stored for seeding during resume */ u8 seed_save[EXYNOS_RNG_SEED_SIZE]; unsigned int seed_save_len; @@ -192,6 +194,10 @@ static void exynos_rng_reseed(struct exynos_rng_dev *rng) return; exynos_rng_set_seed(rng, seed, read); + + /* Let others do some of their job. */ + mutex_unlock(&rng->lock); + mutex_lock(&rng->lock); } static int exynos_rng_generate(struct crypto_rng *tfm, @@ -207,6 +213,7 @@ static int exynos_rng_generate(struct crypto_rng *tfm, if (ret) return ret; + mutex_lock(&rng->lock); do { ret = exynos_rng_get_random(rng, dst, dlen, &read); if (ret) @@ -217,6 +224,7 @@ static int exynos_rng_generate(struct crypto_rng *tfm, exynos_rng_reseed(rng); } while (dlen > 0); + mutex_unlock(&rng->lock); clk_disable_unprepare(rng->clk); @@ -234,7 +242,9 @@ static int exynos_rng_seed(struct crypto_rng *tfm, const u8 *seed, if (ret) return ret; + mutex_lock(&rng->lock); ret = exynos_rng_set_seed(ctx->rng, seed, slen); + mutex_unlock(&rng->lock); clk_disable_unprepare(rng->clk); @@ -284,6 +294,8 @@ static int exynos_rng_probe(struct platform_device *pdev) return -ENOTSUPP; } + mutex_init(&rng->lock); + rng->dev = &pdev->dev; rng->clk = devm_clk_get(&pdev->dev, "secss"); if (IS_ERR(rng->clk)) { @@ -334,9 +346,14 @@ static int __maybe_unused exynos_rng_suspend(struct device *dev) if (ret) return ret; + mutex_lock(&rng->lock); + /* Get new random numbers and store them for seeding on resume. */ exynos_rng_get_random(rng, rng->seed_save, sizeof(rng->seed_save), &(rng->seed_save_len)); + + mutex_unlock(&rng->lock); + dev_dbg(rng->dev, "Stored %u bytes for seeding on system resume\n", rng->seed_save_len); @@ -359,8 +376,12 @@ static int __maybe_unused exynos_rng_resume(struct device *dev) if (ret) return ret; + mutex_lock(&rng->lock); + ret = exynos_rng_set_seed(rng, rng->seed_save, rng->seed_save_len); + mutex_unlock(&rng->lock); + clk_disable_unprepare(rng->clk); return ret; -- 2.11.0