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Tue, 02 Jun 2020 00:25:16 -0800 Received: from MTKMBS01N2.mediatek.inc (172.21.101.79) by MTKMBS62DR.mediatek.inc (172.29.94.18) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 01:15:12 -0700 Received: from mtkcas08.mediatek.inc (172.21.101.126) by mtkmbs01n2.mediatek.inc (172.21.101.79) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 2 Jun 2020 16:14:59 +0800 Received: from mtkswgap22.mediatek.inc (172.21.77.33) by mtkcas08.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Tue, 2 Jun 2020 16:14:58 +0800 From: Neal Liu To: Matt Mackall , Herbert Xu , Rob Herring , Matthias Brugger , Sean Wang , Arnd Bergmann , "Greg Kroah-Hartman" Subject: [PATCH v6 2/2] hwrng: add sec-rng driver Date: Tue, 2 Jun 2020 16:14:38 +0800 Message-ID: <1591085678-22764-3-git-send-email-neal.liu@mediatek.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1591085678-22764-1-git-send-email-neal.liu@mediatek.com> References: <1591085678-22764-1-git-send-email-neal.liu@mediatek.com> MIME-Version: 1.0 X-TM-SNTS-SMTP: 909ABA3B6E64AD00041CC4B3A9BF7D20E656DA2E14FD0DBC349B80906CF174CA2000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200602_012518_602880_D9150D9A X-CRM114-Status: GOOD ( 16.75 ) X-Spam-Score: -0.2 (/) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-0.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 0.0 MIME_BASE64_TEXT RAW: Message text disguised using base64 encoding -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain 0.0 UNPARSEABLE_RELAY Informational: message has unparseable relay lines X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, wsd_upstream@mediatek.com, lkml , Crystal Guo , linux-mediatek@lists.infradead.org, linux-crypto@vger.kernel.org, Neal Liu , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org For security awareness SoCs on ARMv8 with TrustZone enabled, peripherals like entropy sources is not accessible from normal world (linux) and rather accessible from secure world (HYP/ATF/TEE) only. This driver aims to provide a generic interface to Arm Trusted Firmware or Hypervisor rng service. Signed-off-by: Neal Liu --- drivers/char/hw_random/Kconfig | 13 ++++ drivers/char/hw_random/Makefile | 1 + drivers/char/hw_random/sec-rng.c | 155 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 169 insertions(+) create mode 100644 drivers/char/hw_random/sec-rng.c diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index 9bc46da..cb9c8a9 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -474,6 +474,19 @@ config HW_RANDOM_KEYSTONE help This option enables Keystone's hardware random generator. +config HW_RANDOM_SECURE + tristate "Arm Security Random Number Generator support" + depends on HAVE_ARM_SMCCC || COMPILE_TEST + default HW_RANDOM + help + This driver provides kernel-side support for the Arm Security + Random Number Generator. + + To compile this driver as a module, choose M here. the + module will be called sec-rng. + + If unsure, say Y. + endif # HW_RANDOM config UML_RANDOM diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile index a7801b4..04533d1 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -41,3 +41,4 @@ obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o obj-$(CONFIG_HW_RANDOM_NPCM) += npcm-rng.o +obj-$(CONFIG_HW_RANDOM_SECURE) += sec-rng.o diff --git a/drivers/char/hw_random/sec-rng.c b/drivers/char/hw_random/sec-rng.c new file mode 100644 index 0000000..c6d3872 --- /dev/null +++ b/drivers/char/hw_random/sec-rng.c @@ -0,0 +1,155 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020 MediaTek Inc. + */ + +#include +#include +#include +#include +#include + +#define SMC_RET_NUM 4 +#define SEC_RND_SIZE (sizeof(u32) * SMC_RET_NUM) + +#define HWRNG_SMC_FAST_CALL_VAL(func_num) \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_SIP, (func_num)) + +#define to_sec_rng(p) container_of(p, struct sec_rng_priv, rng) + +typedef void (sec_rng_fn)(unsigned long, unsigned long, unsigned long, + unsigned long, unsigned long, unsigned long, + unsigned long, unsigned long, + struct arm_smccc_res *); + +struct sec_rng_priv { + u16 func_num; + sec_rng_fn *rng_fn; + struct hwrng rng; +}; + +/* Simple wrapper functions to be able to use a function pointer */ +static void sec_rng_smc(unsigned long a0, unsigned long a1, + unsigned long a2, unsigned long a3, + unsigned long a4, unsigned long a5, + unsigned long a6, unsigned long a7, + struct arm_smccc_res *res) +{ + arm_smccc_smc(a0, a1, a2, a3, a4, a5, a6, a7, res); +} + +static void sec_rng_hvc(unsigned long a0, unsigned long a1, + unsigned long a2, unsigned long a3, + unsigned long a4, unsigned long a5, + unsigned long a6, unsigned long a7, + struct arm_smccc_res *res) +{ + arm_smccc_hvc(a0, a1, a2, a3, a4, a5, a6, a7, res); +} + +static bool __sec_get_rnd(struct sec_rng_priv *priv, uint32_t *val) +{ + struct arm_smccc_res res; + + priv->rng_fn(HWRNG_SMC_FAST_CALL_VAL(priv->func_num), + 0, 0, 0, 0, 0, 0, 0, &res); + + if (!res.a0 && !res.a1 && !res.a2 && !res.a3) + return false; + + val[0] = res.a0; + val[1] = res.a1; + val[2] = res.a2; + val[3] = res.a3; + + return true; +} + +static int sec_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) +{ + struct sec_rng_priv *priv = to_sec_rng(rng); + u32 val[4] = {0}; + int retval = 0; + int i; + + while (max >= SEC_RND_SIZE) { + if (!__sec_get_rnd(priv, val)) + return retval; + + for (i = 0; i < SMC_RET_NUM; i++) { + *(u32 *)buf = val[i]; + buf += sizeof(u32); + } + + retval += SEC_RND_SIZE; + max -= SEC_RND_SIZE; + } + + return retval; +} + +static int sec_rng_probe(struct platform_device *pdev) +{ + struct sec_rng_priv *priv; + const char *method; + int ret; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + if (of_property_read_string(pdev->dev.of_node, "method", &method)) + return -ENXIO; + + if (!strncmp("smc", method, strlen("smc"))) + priv->rng_fn = sec_rng_smc; + else if (!strncmp("hvc", method, strlen("hvc"))) + priv->rng_fn = sec_rng_hvc; + + if (IS_ERR(priv->rng_fn)) { + dev_err(&pdev->dev, "method %s is not supported\n", method); + return -EINVAL; + } + + if (of_property_read_u16(pdev->dev.of_node, "method-fid", + &priv->func_num)) + return -ENXIO; + + if (of_property_read_u16(pdev->dev.of_node, "quality", + &priv->rng.quality)) + return -ENXIO; + + priv->rng.name = pdev->name; + priv->rng.read = sec_rng_read; + priv->rng.priv = (unsigned long)&pdev->dev; + + ret = devm_hwrng_register(&pdev->dev, &priv->rng); + if (ret) { + dev_err(&pdev->dev, "failed to register rng device: %d\n", ret); + return ret; + } + + return 0; +} + +static const struct of_device_id sec_rng_match[] = { + { .compatible = "arm,sec-rng", }, + {} +}; +MODULE_DEVICE_TABLE(of, sec_rng_match); + +static struct platform_driver sec_rng_driver = { + .probe = sec_rng_probe, + .driver = { + .name = KBUILD_MODNAME, + .owner = THIS_MODULE, + .of_match_table = sec_rng_match, + }, +}; + +module_platform_driver(sec_rng_driver); + +MODULE_DESCRIPTION("Security Random Number Generator Driver"); +MODULE_AUTHOR("Neal Liu "); +MODULE_LICENSE("GPL");