| Message ID | 1548062959-31860-1-git-send-email-sumit.garg@linaro.org |
|---|---|
| Headers | show |
| Series | Introduce TEE bus driver framework | expand |
On Mon, 21 Jan 2019 at 13:59, Sumit Garg <sumit.garg@linaro.org> wrote: > > On Mon, 21 Jan 2019 at 15:33, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote: > > > > On Mon, 21 Jan 2019 at 10:30, Sumit Garg <sumit.garg@linaro.org> wrote: > > > > > > On ARM SoC's with TrustZone enabled, peripherals like entropy sources > > > might not be accessible to normal world (linux in this case) and rather > > > accessible to secure world (OP-TEE in this case) only. So this driver > > > aims to provides a generic interface to OP-TEE based random number > > > generator service. > > > > > > This driver registers on TEE bus to interact with OP-TEE based rng > > > device/service. > > > > > > Signed-off-by: Sumit Garg <sumit.garg@linaro.org> > > > --- > > > MAINTAINERS | 5 + > > > drivers/char/hw_random/Kconfig | 15 ++ > > > drivers/char/hw_random/Makefile | 1 + > > > drivers/char/hw_random/optee-rng.c | 272 +++++++++++++++++++++++++++++++++++++ > > > 4 files changed, 293 insertions(+) > > > create mode 100644 drivers/char/hw_random/optee-rng.c > > > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > > index 32d44447..502733c 100644 > > > --- a/MAINTAINERS > > > +++ b/MAINTAINERS > > > @@ -11260,6 +11260,11 @@ M: Jens Wiklander <jens.wiklander@linaro.org> > > > S: Maintained > > > F: drivers/tee/optee/ > > > > > > +OP-TEE RANDOM NUMBER GENERATOR (RNG) DRIVER > > > +M: Sumit Garg <sumit.garg@linaro.org> > > > +S: Maintained > > > +F: drivers/char/hw_random/optee-rng.c > > > + > > > OPA-VNIC DRIVER > > > M: Dennis Dalessandro <dennis.dalessandro@intel.com> > > > M: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com> > > > diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig > > > index dac895d..25a7d8f 100644 > > > --- a/drivers/char/hw_random/Kconfig > > > +++ b/drivers/char/hw_random/Kconfig > > > @@ -424,6 +424,21 @@ config HW_RANDOM_EXYNOS > > > will be called exynos-trng. > > > > > > If unsure, say Y. > > > + > > > +config HW_RANDOM_OPTEE > > > + tristate "OP-TEE based Random Number Generator support" > > > + depends on OPTEE > > > + default HW_RANDOM > > > + help > > > + This driver provides support for OP-TEE based Random Number > > > + Generator on ARM SoCs where hardware entropy sources are not > > > + accessible to normal world (Linux). > > > + > > > + To compile this driver as a module, choose M here: the module > > > + will be called optee-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 e35ec3c..7c9ef4a 100644 > > > --- a/drivers/char/hw_random/Makefile > > > +++ b/drivers/char/hw_random/Makefile > > > @@ -38,3 +38,4 @@ obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o > > > obj-$(CONFIG_HW_RANDOM_MTK) += mtk-rng.o > > > 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 > > > diff --git a/drivers/char/hw_random/optee-rng.c b/drivers/char/hw_random/optee-rng.c > > > new file mode 100644 > > > index 0000000..6ac862a > > > --- /dev/null > > > +++ b/drivers/char/hw_random/optee-rng.c > > > @@ -0,0 +1,272 @@ > > > +// SPDX-License-Identifier: GPL-2.0 > > > +/* > > > + * Copyright (C) 2018-2019 Linaro Ltd. > > > + */ > > > + > > > +#include <linux/delay.h> > > > +#include <linux/of.h> > > > +#include <linux/hw_random.h> > > > +#include <linux/kernel.h> > > > +#include <linux/module.h> > > > +#include <linux/slab.h> > > > +#include <linux/tee_drv.h> > > > +#include <linux/uuid.h> > > > + > > > +#define DRIVER_NAME "optee-rng" > > > + > > > +#define TEE_ERROR_HEALTH_TEST_FAIL 0x00000001 > > > + > > > +/* > > > + * TA_CMD_GET_ENTROPY - Get Entropy from RNG > > > + * > > > + * param[0] (inout memref) - Entropy buffer memory reference > > > + * param[1] unused > > > + * param[2] unused > > > + * param[3] unused > > > + * > > > + * Result: > > > + * TEE_SUCCESS - Invoke command success > > > + * TEE_ERROR_BAD_PARAMETERS - Incorrect input param > > > + * TEE_ERROR_NOT_SUPPORTED - Requested entropy size greater than size of pool > > > + * TEE_ERROR_HEALTH_TEST_FAIL - Continuous health testing failed > > > + */ > > > +#define TA_CMD_GET_ENTROPY 0x0 > > > + > > > +/* > > > + * TA_CMD_GET_RNG_INFO - Get RNG information > > > + * > > > + * param[0] (out value) - value.a: RNG data-rate in bytes per second > > > + * value.b: Quality/Entropy per 1024 bit of data > > > + * param[1] unused > > > + * param[2] unused > > > + * param[3] unused > > > + * > > > + * Result: > > > + * TEE_SUCCESS - Invoke command success > > > + * TEE_ERROR_BAD_PARAMETERS - Incorrect input param > > > + */ > > > +#define TA_CMD_GET_RNG_INFO 0x1 > > > + > > > +#define MAX_ENTROPY_REQ_SZ (4 * 1024) > > > + > > > +static struct tee_context *ctx; > > > +static struct tee_shm *entropy_shm_pool; > > > +static u32 ta_rng_data_rate; > > > +static u32 ta_rng_session_id; > > > + > > > +static size_t get_optee_rng_data(void *buf, size_t req_size) > > > +{ > > > + u32 ret = 0; > > > + u8 *rng_data = NULL; > > > + size_t rng_size = 0; > > > + struct tee_ioctl_invoke_arg inv_arg = {0}; > > > + struct tee_param param[4] = {0}; > > > + > > > + /* Invoke TA_CMD_GET_ENTROPY function of Trusted App */ > > > + inv_arg.func = TA_CMD_GET_ENTROPY; > > > + inv_arg.session = ta_rng_session_id; > > > + inv_arg.num_params = 4; > > > + > > > + /* Fill invoke cmd params */ > > > + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT; > > > + param[0].u.memref.shm = entropy_shm_pool; > > > + param[0].u.memref.size = req_size; > > > + param[0].u.memref.shm_offs = 0; > > > + > > > + ret = tee_client_invoke_func(ctx, &inv_arg, param); > > > + if ((ret < 0) || (inv_arg.ret != 0)) { > > > + pr_err("TA_CMD_GET_ENTROPY invoke function error: %x\n", > > > + inv_arg.ret); > > > + return 0; > > > + } > > > + > > > + rng_data = tee_shm_get_va(entropy_shm_pool, 0); > > > + if (IS_ERR(rng_data)) { > > > + pr_err("tee_shm_get_va failed\n"); > > > + return 0; > > > + } > > > + > > > + rng_size = param[0].u.memref.size; > > > + memcpy(buf, rng_data, rng_size); > > > + > > > + return rng_size; > > > +} > > > + > > > +static int optee_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) > > > +{ > > > + u8 *data = buf; > > > + size_t read = 0, rng_size = 0; > > > + int timeout = 1; > > > + > > > + if (max > MAX_ENTROPY_REQ_SZ) > > > + max = MAX_ENTROPY_REQ_SZ; > > > + > > > + while (read == 0) { > > > + rng_size = get_optee_rng_data(data, (max - read)); > > > + > > > + data += rng_size; > > > + read += rng_size; > > > + > > > + if (wait) { > > > + if (timeout-- == 0) > > > + return read; > > > + msleep((1000 * (max - read)) / ta_rng_data_rate); > > > + } else { > > > + return read; > > > + } > > > + } > > > + > > > + return read; > > > +} > > > + > > > +static int optee_rng_init(struct hwrng *rng) > > > +{ > > > + entropy_shm_pool = tee_shm_alloc(ctx, MAX_ENTROPY_REQ_SZ, > > > + TEE_SHM_MAPPED | TEE_SHM_DMA_BUF); > > > + if (IS_ERR(entropy_shm_pool)) { > > > + pr_err("tee_shm_alloc failed\n"); > > > + return PTR_ERR(entropy_shm_pool); > > > + } > > > + > > > + return 0; > > > +} > > > + > > > +static void optee_rng_cleanup(struct hwrng *rng) > > > +{ > > > + tee_shm_free(entropy_shm_pool); > > > +} > > > + > > > +static struct hwrng optee_rng = { > > > + .name = DRIVER_NAME, > > > + .init = optee_rng_init, > > > + .cleanup = optee_rng_cleanup, > > > + .read = optee_rng_read, > > > +}; > > > + > > > +static int get_optee_rng_info(struct device *dev) > > > +{ > > > + u32 ret = 0; > > > + struct tee_ioctl_invoke_arg inv_arg = {0}; > > > + struct tee_param param[4] = {0}; > > > + > > > + /* Invoke TA_CMD_GET_RNG_INFO function of Trusted App */ > > > + inv_arg.func = TA_CMD_GET_RNG_INFO; > > > + inv_arg.session = ta_rng_session_id; > > > + inv_arg.num_params = 4; > > > + > > > + /* Fill invoke cmd params */ > > > + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT; > > > + > > > + ret = tee_client_invoke_func(ctx, &inv_arg, param); > > > + if ((ret < 0) || (inv_arg.ret != 0)) { > > > + dev_err(dev, "TA_CMD_GET_RNG_INFO invoke func error: %x\n", > > > + inv_arg.ret); > > > + return -EINVAL; > > > + } > > > + > > > + ta_rng_data_rate = param[0].u.value.a; > > > + optee_rng.quality = param[0].u.value.b; > > > + > > > + return 0; > > > +} > > > + > > > +static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data) > > > +{ > > > + if (ver->impl_id == TEE_IMPL_ID_OPTEE) > > > + return 1; > > > + else > > > + return 0; > > > +} > > > + > > > +static int optee_rng_probe(struct device *dev) > > > +{ > > > + struct tee_client_device *rng_device = to_tee_client_device(dev); > > > + int ret = 0, err = -ENODEV; > > > + struct tee_ioctl_open_session_arg sess_arg = {0}; > > > + > > > + /* Open context with TEE driver */ > > > + ctx = tee_client_open_context(NULL, optee_ctx_match, NULL, NULL); > > > + if (IS_ERR(ctx)) > > > + return -ENODEV; > > > + > > > + /* Open session with hwrng Trusted App */ > > > + memcpy(sess_arg.uuid, rng_device->id.b, TEE_IOCTL_UUID_LEN); > > > + sess_arg.clnt_login = TEE_IOCTL_LOGIN_PUBLIC; > > > + sess_arg.num_params = 0; > > > + > > > + ret = tee_client_open_session(ctx, &sess_arg, NULL); > > > + if ((ret < 0) || (sess_arg.ret != 0)) { > > > + dev_err(dev, "tee_client_open_session failed, error: %x\n", > > > + sess_arg.ret); > > > + err = -EINVAL; > > > + goto out_ctx; > > > + } > > > + ta_rng_session_id = sess_arg.session; > > > + > > > + err = get_optee_rng_info(dev); > > > + if (err) > > > + goto out_sess; > > > + > > > + err = hwrng_register(&optee_rng); > > > + if (err) { > > > + dev_err(dev, "hwrng registration failed (%d)\n", err); > > > + goto out_sess; > > > + } > > > + > > > + return 0; > > > + > > > +out_sess: > > > + tee_client_close_session(ctx, ta_rng_session_id); > > > +out_ctx: > > > + tee_client_close_context(ctx); > > > + > > > + return err; > > > +} > > > + > > > +static int optee_rng_remove(struct device *dev) > > > +{ > > > + hwrng_unregister(&optee_rng); > > > + tee_client_close_session(ctx, ta_rng_session_id); > > > + tee_client_close_context(ctx); > > > + > > > + return 0; > > > +} > > > + > > > +const tee_client_device_id optee_rng_id_table[] = { > > > + UUID_INIT(0xab7a617c, 0xb8e7, 0x4d8f, > > > + 0x83, 0x01, 0xd0, 0x9b, 0x61, 0x03, 0x6b, 0x64), > > > + {} > > > +}; > > > + > > > > Could we expose this via MODULE_DEVICE_TABLE() as well? That should > > allow udev to load the module on demand. > > > > IIUC, here you are referring to addition of "modalias" infrastructure > for TEE bus. I think this is good feature to have for automatic > out-of-tree module loading via udev. Shall I create a separate patch > for this feature addition rather than including it in this patch-set? > > Currently I use to put this module entry in /etc/modules for auto-loading. > I wouldn't call that auto-loading :-) But seriously, I think it provides an important rationale for the patch set as a whole, so I would prefer it if it were included.