by Mathieu Poirier

[permalink] [raw]

Subject: Re: [PATCH v4 1/4] remoteproc: Add TEE support

On Fri, Mar 29, 2024 at 09:58:11AM +0100, Arnaud POULIQUEN wrote:
> Hello Mathieu,
>
> On 3/27/24 18:07, Mathieu Poirier wrote:
> > On Tue, Mar 26, 2024 at 08:18:23PM +0100, Arnaud POULIQUEN wrote:
> >> Hello Mathieu,
> >>
> >> On 3/25/24 17:46, Mathieu Poirier wrote:
> >>> On Fri, Mar 08, 2024 at 03:47:05PM +0100, Arnaud Pouliquen wrote:
> >>>> Add a remoteproc TEE (Trusted Execution Environment) driver
> >>>> that will be probed by the TEE bus. If the associated Trusted
> >>>> application is supported on secure part this device offers a client
> >>>
> >>> Device or driver? I thought I touched on that before.
> >>
> >> Right, I changed the first instance and missed this one
> >>
> >>>
> >>>> interface to load a firmware in the secure part.
> >>>> This firmware could be authenticated by the secure trusted application.
> >>>>
> >>>> Signed-off-by: Arnaud Pouliquen <[email protected]>
> >>>> ---
> >>>> Updates from V3:
> >>>> - rework TEE_REMOTEPROC description in Kconfig
> >>>> - fix some namings
> >>>> - add tee_rproc_parse_fw to support rproc_ops::parse_fw
> >>>> - add proc::tee_interface;
> >>>> - add rproc struct as parameter of the tee_rproc_register() function
> >>>> ---
> >>>> drivers/remoteproc/Kconfig | 10 +
> >>>> drivers/remoteproc/Makefile | 1 +
> >>>> drivers/remoteproc/tee_remoteproc.c | 434 ++++++++++++++++++++++++++++
> >>>> include/linux/remoteproc.h | 4 +
> >>>> include/linux/tee_remoteproc.h | 112 +++++++
> >>>> 5 files changed, 561 insertions(+)
> >>>> create mode 100644 drivers/remoteproc/tee_remoteproc.c
> >>>> create mode 100644 include/linux/tee_remoteproc.h
> >>>>
> >>>> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> >>>> index 48845dc8fa85..2cf1431b2b59 100644
> >>>> --- a/drivers/remoteproc/Kconfig
> >>>> +++ b/drivers/remoteproc/Kconfig
> >>>> @@ -365,6 +365,16 @@ config XLNX_R5_REMOTEPROC
> >>>>
> >>>> It's safe to say N if not interested in using RPU r5f cores.
> >>>>
> >>>> +
> >>>> +config TEE_REMOTEPROC
> >>>> + tristate "remoteproc support by a TEE application"
> >>>
> >>> s/remoteproc/Remoteproc
> >>>
> >>>> + depends on OPTEE
> >>>> + help
> >>>> + Support a remote processor with a TEE application. The Trusted
> >>>> + Execution Context is responsible for loading the trusted firmware
> >>>> + image and managing the remote processor's lifecycle.
> >>>> + This can be either built-in or a loadable module.
> >>>> +
> >>>> endif # REMOTEPROC
> >>>>
> >>>> endmenu
> >>>> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> >>>> index 91314a9b43ce..fa8daebce277 100644
> >>>> --- a/drivers/remoteproc/Makefile
> >>>> +++ b/drivers/remoteproc/Makefile
> >>>> @@ -36,6 +36,7 @@ obj-$(CONFIG_RCAR_REMOTEPROC) += rcar_rproc.o
> >>>> obj-$(CONFIG_ST_REMOTEPROC) += st_remoteproc.o
> >>>> obj-$(CONFIG_ST_SLIM_REMOTEPROC) += st_slim_rproc.o
> >>>> obj-$(CONFIG_STM32_RPROC) += stm32_rproc.o
> >>>> +obj-$(CONFIG_TEE_REMOTEPROC) += tee_remoteproc.o
> >>>> obj-$(CONFIG_TI_K3_DSP_REMOTEPROC) += ti_k3_dsp_remoteproc.o
> >>>> obj-$(CONFIG_TI_K3_R5_REMOTEPROC) += ti_k3_r5_remoteproc.o
> >>>> obj-$(CONFIG_XLNX_R5_REMOTEPROC) += xlnx_r5_remoteproc.o
> >>>> diff --git a/drivers/remoteproc/tee_remoteproc.c b/drivers/remoteproc/tee_remoteproc.c
> >>>> new file mode 100644
> >>>> index 000000000000..c855210e52e3
> >>>> --- /dev/null
> >>>> +++ b/drivers/remoteproc/tee_remoteproc.c
> >>>> @@ -0,0 +1,434 @@
> >>>> +// SPDX-License-Identifier: GPL-2.0-or-later
> >>>> +/*
> >>>> + * Copyright (C) STMicroelectronics 2024 - All Rights Reserved
> >>>> + * Author: Arnaud Pouliquen <[email protected]>
> >>>> + */
> >>>> +
> >>>> +#include <linux/firmware.h>
> >>>> +#include <linux/io.h>
> >>>> +#include <linux/module.h>
> >>>> +#include <linux/remoteproc.h>
> >>>> +#include <linux/slab.h>
> >>>> +#include <linux/tee_drv.h>
> >>>> +#include <linux/tee_remoteproc.h>
> >>>> +
> >>>> +#include "remoteproc_internal.h"
> >>>> +
> >>>> +#define MAX_TEE_PARAM_ARRY_MEMBER 4
> >>>> +
> >>>> +/*
> >>>> + * Authentication of the firmware and load in the remote processor memory
> >>>> + *
> >>>> + * [in] params[0].value.a: unique 32bit identifier of the remote processor
> >>>> + * [in] params[1].memref: buffer containing the image of the buffer
> >>>> + */
> >>>> +#define TA_RPROC_FW_CMD_LOAD_FW 1
> >>>> +
> >>>> +/*
> >>>> + * Start the remote processor
> >>>> + *
> >>>> + * [in] params[0].value.a: unique 32bit identifier of the remote processor
> >>>> + */
> >>>> +#define TA_RPROC_FW_CMD_START_FW 2
> >>>> +
> >>>> +/*
> >>>> + * Stop the remote processor
> >>>> + *
> >>>> + * [in] params[0].value.a: unique 32bit identifier of the remote processor
> >>>> + */
> >>>> +#define TA_RPROC_FW_CMD_STOP_FW 3
> >>>> +
> >>>> +/*
> >>>> + * Return the address of the resource table, or 0 if not found
> >>>> + * No check is done to verify that the address returned is accessible by
> >>>> + * the non secure context. If the resource table is loaded in a protected
> >>>> + * memory the access by the non secure context will lead to a data abort.
> >>>> + *
> >>>> + * [in] params[0].value.a: unique 32bit identifier of the remote processor
> >>>> + * [out] params[1].value.a: 32bit LSB resource table memory address
> >>>> + * [out] params[1].value.b: 32bit MSB resource table memory address
> >>>> + * [out] params[2].value.a: 32bit LSB resource table memory size
> >>>> + * [out] params[2].value.b: 32bit MSB resource table memory size
> >>>> + */
> >>>> +#define TA_RPROC_FW_CMD_GET_RSC_TABLE 4
> >>>> +
> >>>> +/*
> >>>> + * Return the address of the core dump
> >>>> + *
> >>>> + * [in] params[0].value.a: unique 32bit identifier of the remote processor
> >>>> + * [out] params[1].memref: address of the core dump image if exist,
> >>>> + * else return Null
> >>>> + */
> >>>> +#define TA_RPROC_FW_CMD_GET_COREDUMP 5
> >>>> +
> >>>> +struct tee_rproc_context {
> >>>> + struct list_head sessions;
> >>>> + struct tee_context *tee_ctx;
> >>>> + struct device *dev;
> >>>> +};
> >>>> +
> >>>> +static struct tee_rproc_context *tee_rproc_ctx;
> >>>> +
> >>>> +static void tee_rproc_prepare_args(struct tee_rproc *trproc, int cmd,
> >>>> + struct tee_ioctl_invoke_arg *arg,
> >>>> + struct tee_param *param,
> >>>> + unsigned int num_params)
> >>>> +{
> >>>> + memset(arg, 0, sizeof(*arg));
> >>>> + memset(param, 0, MAX_TEE_PARAM_ARRY_MEMBER * sizeof(*param));
> >>>> +
> >>>> + arg->func = cmd;
> >>>> + arg->session = trproc->session_id;
> >>>> + arg->num_params = num_params + 1;
> >>>> +
> >>>> + param[0] = (struct tee_param) {
> >>>> + .attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> >>>> + .u.value.a = trproc->rproc_id,
> >>>> + };
> >>>> +}
> >>>> +
> >>>> +int tee_rproc_load_fw(struct rproc *rproc, const struct firmware *fw)
> >>>> +{
> >>>> + struct tee_ioctl_invoke_arg arg;
> >>>> + struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
> >>>> + struct tee_rproc *trproc = rproc->tee_interface;
> >>>> + struct tee_shm *fw_shm;
> >>>> + int ret;
> >>>
> >>> Declarations in reverse ascending order here and everywhere in the driver.
> >>> Sometimes it is done properly, sometimes it isn't.
> >>>
> >>>> +
> >>>> + if (!trproc)
> >>>> + return -EINVAL;
> >>>> +
> >>>> + fw_shm = tee_shm_register_kernel_buf(tee_rproc_ctx->tee_ctx, (void *)fw->data, fw->size);
> >>>> + if (IS_ERR(fw_shm))
> >>>> + return PTR_ERR(fw_shm);
> >>>> +
> >>>> + tee_rproc_prepare_args(trproc, TA_RPROC_FW_CMD_LOAD_FW, &arg, param, 1);
> >>>> +
> >>>> + /* Provide the address of the firmware image */
> >>>> + param[1] = (struct tee_param) {
> >>>> + .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT,
> >>>> + .u.memref = {
> >>>> + .shm = fw_shm,
> >>>> + .size = fw->size,
> >>>> + .shm_offs = 0,
> >>>> + },
> >>>> + };
> >>>> +
> >>>> + ret = tee_client_invoke_func(tee_rproc_ctx->tee_ctx, &arg, param);
> >>>> + if (ret < 0 || arg.ret != 0) {
> >>>> + dev_err(tee_rproc_ctx->dev,
> >>>> + "TA_RPROC_FW_CMD_LOAD_FW invoke failed TEE err: %x, ret:%x\n",
> >>>> + arg.ret, ret);
> >>>> + if (!ret)
> >>>> + ret = -EIO;
> >>>> + }
> >>>> +
> >>>> + tee_shm_free(fw_shm);
> >>>> +
> >>>> + return ret;
> >>>> +}
> >>>> +EXPORT_SYMBOL_GPL(tee_rproc_load_fw);
> >>>> +
> >>>> +struct resource_table *tee_rproc_get_loaded_rsc_table(struct rproc *rproc, size_t *table_sz)
> >>>> +{
> >>>> + struct tee_ioctl_invoke_arg arg;
> >>>> + struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
> >>>> + struct tee_rproc *trproc = rproc->tee_interface;
> >>>> + struct resource_table *rsc_table;
> >>>> + int ret;
> >>>> +
> >>>> + if (!trproc)
> >>>> + return ERR_PTR(-EINVAL);
> >>>> +
> >>>> + tee_rproc_prepare_args(trproc, TA_RPROC_FW_CMD_GET_RSC_TABLE, &arg, param, 2);
> >>>> +
> >>>> + param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
> >>>> + param[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
> >>>> +
> >>>> + ret = tee_client_invoke_func(tee_rproc_ctx->tee_ctx, &arg, param);
> >>>> + if (ret < 0 || arg.ret != 0) {
> >>>> + dev_err(tee_rproc_ctx->dev,
> >>>> + "TA_RPROC_FW_CMD_GET_RSC_TABLE invoke failed TEE err: %x, ret:%x\n",
> >>>> + arg.ret, ret);
> >>>> + return ERR_PTR(-EIO);
> >>>> + }
> >>>> +
> >>>> + *table_sz = param[2].u.value.a;
> >>>> +
> >>>> + /* If the size is null no resource table defined in the image */
> >>>> + if (!*table_sz)
> >>>> + return NULL;
> >>>> +
> >>>> + /* Store the resource table address that would be updated by the remote core. */
> >>>> + rsc_table = ioremap_wc(param[1].u.value.a, *table_sz);
> >>>> + if (IS_ERR_OR_NULL(rsc_table)) {
> >>>> + dev_err(tee_rproc_ctx->dev, "Unable to map memory region: %lld+%zx\n",
> >>>> + param[1].u.value.a, *table_sz);
> >>>> + return ERR_PTR(-ENOMEM);
> >>>> + }
> >>>> +
> >>>> + return rsc_table;
> >>>> +}
> >>>> +EXPORT_SYMBOL_GPL(tee_rproc_get_loaded_rsc_table);
> >>>> +
> >>>> +int tee_rproc_parse_fw(struct rproc *rproc, const struct firmware *fw)
> >>>> +{
> >>>> + struct tee_rproc *trproc = rproc->tee_interface;
> >>>> + struct resource_table *rsc_table;
> >>>> + size_t table_sz;
> >>>> + int ret;
> >>>> +
> >>>> + ret = tee_rproc_load_fw(rproc, fw);
> >>>> + if (ret)
> >>>> + return ret;
> >>>> +
> >>>> + rsc_table = tee_rproc_get_loaded_rsc_table(rproc, &table_sz);
> >>>> + if (IS_ERR(rsc_table))
> >>>> + return PTR_ERR(rsc_table);
> >>>> +
> >>>> + /* Create a copy of the resource table to have same behaviour than the elf loader. */
> >>>> + rproc->cached_table = kmemdup(rsc_table, table_sz, GFP_KERNEL);
> >>>> + if (!rproc->cached_table)
> >>>> + return -ENOMEM;
> >>>
> >>> Why not ->table_ptr and setting ->cached_table to NULL?
> >>
> >> It was my plan preparing this version. But during implementarion it looks
> >> to me that having exactly same behavior than the ELF loader would be
> >> simpler to maintain the remoteproc avoiding to update in the remoteproc core
> >> to manage for the cached resource table (see also my comment below abourt recovery)
> >> That why I propose this implementation
> >>
> >> That said what you proposal should also work (with some updates in
> >> remoteproc_core for the management of the cached table).
> >>
> >
> > Yes
> >
> >> So please just comfirm your preference.
> >>
> >
> > Definitely keep ->cached_table to NULL.
> >
> >>>
> >>>> +
> >>>> + rproc->table_ptr = rproc->cached_table;
> >>>> + rproc->table_sz = table_sz;
> >>>> + trproc->rsc_table = rsc_table;
> >>>
> >>> I really don't see why this is needed, please remove and use rproc->table_ptr
> >>> instead.
> >>
> >> I need to store it for the iounmap in tee_rproc_remove.
> >
> > iounmap(entry->rproc->rsc_table);
> >
> > What am I missing?
>
> rproc->rsc_table is a field that can be updated by remoteproc_core.
> How can we garanty in tee_remoteproc that it still points to the mapped resource
> table?

By making sure the core doesn't touch rproc->rsc_table when
rproc->tee_interface is valid.

> As the remoteproc_tee maps the pointer, it seems reliable that it stores it for
> unmap.
>

Doing so creates a shadow value that is confusing and really hard to maintain
going forward.

> Seems also that I also missed to handle the case where rproc_fw_boot() fails[3]
> (not done yet).
>
> [3]https://elixir.bootlin.com/linux/latest/source/drivers/remoteproc/remoteproc_core.c#L1442
>
>
> >
> >>
> >>>
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +EXPORT_SYMBOL_GPL(tee_rproc_parse_fw);
> >>>> +
> >>>> +struct resource_table *tee_rproc_find_loaded_rsc_table(struct rproc *rproc,
> >>>> + const struct firmware *fw)
> >>>> +{
> >>>> + struct tee_rproc *trproc = rproc->tee_interface;
> >>>> + struct resource_table *rsc_table;
> >>>> + size_t table_sz;
> >>>> +
> >>>> + if (!trproc)
> >>>> + return ERR_PTR(-EINVAL);
> >>>> +
> >>>> + /* Check if the resourse table has already been obtained in tee_rproc_parse_fw() */
> >>>> + if (trproc->rsc_table)
> >>>> + return trproc->rsc_table;
> >>>
> >>> Again, why not simply use rproc->rsc_table? This function should only return
> >>> the resource table that was set in tee_rproc_parse_fw().
> >>
> >> In case of recovery rproc->_rsc_table point to the cached table [1]
> >
> > In [1], on line 1554, add a check for rproc->tee_interface and if it is valid
> > call rproc_find_loaded_rsc_table().
> >
> >> and we need to reapply the configuration in rproc_start() called during the
> >> recovery[2]
> >
> > 1) Rename rproc_set_rsc_table() to rproc_set_rsc_table_on_attach()
> > 2) Introduce a new function called rproc_set_rsc_table_on_start()
> > 3) Move code from [2], line 1278 to 1292, to that new function. In the new
> > function, add a check on rproc->tee_interface. If it is valid then call
> > rproc_find_loaded_rsc_table().
> > 4) in rproc_start(), replace lines 1278 to 1292 with a call to
> > rproc_set_rsc_table_on_start().
>
>
> I will try this
>

Ok

> Thanks!
> Arnaud
>
> >
> >> [1]https://elixir.bootlin.com/linux/latest/source/drivers/remoteproc/remoteproc_core.c#L1586
> >> [2]https://elixir.bootlin.com/linux/latest/source/drivers/remoteproc/remoteproc_core.c#L1287
> >>
> >>>
> >>>> +
> >>>> + rsc_table = tee_rproc_get_loaded_rsc_table(rproc, &table_sz);
> >>>> + if (IS_ERR(rsc_table))
> >>>> + return rsc_table;
> >>>> +
> >>>> + rproc->table_sz = table_sz;
> >>>> + trproc->rsc_table = rsc_table;
> >>>> +
> >>>> + return rsc_table;
> >>>> +}
> >>>> +EXPORT_SYMBOL_GPL(tee_rproc_find_loaded_rsc_table);
> >>>> +
> >>>> +int tee_rproc_start(struct rproc *rproc)
> >>>> +{
> >>>> + struct tee_ioctl_invoke_arg arg;
> >>>> + struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
> >>>> + struct tee_rproc *trproc = rproc->tee_interface;
> >>>> + int ret;
> >>>> +
> >>>> + if (!trproc)
> >>>> + return -EINVAL;
> >>>> +
> >>>> + tee_rproc_prepare_args(trproc, TA_RPROC_FW_CMD_START_FW, &arg, param, 0);
> >>>> +
> >>>> + ret = tee_client_invoke_func(tee_rproc_ctx->tee_ctx, &arg, param);
> >>>> + if (ret < 0 || arg.ret != 0) {
> >>>> + dev_err(tee_rproc_ctx->dev,
> >>>> + "TA_RPROC_FW_CMD_START_FW invoke failed TEE err: %x, ret:%x\n",
> >>>> + arg.ret, ret);
> >>>> + if (!ret)
> >>>> + ret = -EIO;
> >>>> + }
> >>>> +
> >>>> + return ret;
> >>>> +}
> >>>> +EXPORT_SYMBOL_GPL(tee_rproc_start);
> >>>> +
> >>>> +int tee_rproc_stop(struct rproc *rproc)
> >>>> +{
> >>>> + struct tee_ioctl_invoke_arg arg;
> >>>> + struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
> >>>> + struct tee_rproc *trproc = rproc->tee_interface;
> >>>> + int ret;
> >>>> +
> >>>> + if (!trproc)
> >>>> + return -EINVAL;
> >>>> +
> >>>> + tee_rproc_prepare_args(trproc, TA_RPROC_FW_CMD_STOP_FW, &arg, param, 0);
> >>>> +
> >>>> + ret = tee_client_invoke_func(tee_rproc_ctx->tee_ctx, &arg, param);
> >>>> + if (ret < 0 || arg.ret != 0) {
> >>>> + dev_err(tee_rproc_ctx->dev,
> >>>> + "TA_RPROC_FW_CMD_STOP_FW invoke failed TEE err: %x, ret:%x\n",
> >>>> + arg.ret, ret);
> >>>> + if (!ret)
> >>>> + ret = -EIO;
> >>>> + }
> >>>> +
> >>>> + if (!rproc->table_ptr)
> >>>> + return ret;
> >>>> +
> >>>> + iounmap(trproc->rsc_table);
> >>>> + trproc->rsc_table = NULL;
> >>>> + rproc->table_ptr = NULL;
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +EXPORT_SYMBOL_GPL(tee_rproc_stop);
> >>>> +
> >>>> +static const struct tee_client_device_id stm32_tee_rproc_id_table[] = {
> >>>> + {UUID_INIT(0x80a4c275, 0x0a47, 0x4905,
> >>>> + 0x82, 0x85, 0x14, 0x86, 0xa9, 0x77, 0x1a, 0x08)},
> >>>> + {}
> >>>> +};
> >>>> +
> >>>> +struct tee_rproc *tee_rproc_register(struct device *dev, struct rproc *rproc, unsigned int rproc_id)
> >>>> +{
> >>>> + struct tee_client_device *tee_device;
> >>>> + struct tee_ioctl_open_session_arg sess_arg;
> >>>> + struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
> >>>> + struct tee_rproc *trproc;
> >>>> + int ret;
> >>>> +
> >>>> + /*
> >>>> + * Test if the device has been probed by the TEE bus. In case of failure, we ignore the
> >>>> + * reason. The bus could be not yet probed or the service not available in the secure
> >>>> + * firmware.The assumption in such a case is that the TEE remoteproc is not probed.
> >>>> + */
> >>>> + if (!tee_rproc_ctx)
> >>>> + return ERR_PTR(-EPROBE_DEFER);
> >>>> +
> >>>> + trproc = devm_kzalloc(dev, sizeof(*trproc), GFP_KERNEL);
> >>>> + if (!trproc)
> >>>> + return ERR_PTR(-ENOMEM);
> >>>> +
> >>>> + tee_device = to_tee_client_device(tee_rproc_ctx->dev);
> >>>> + memset(&sess_arg, 0, sizeof(sess_arg));
> >>>> +
> >>>> + memcpy(sess_arg.uuid, tee_device->id.uuid.b, TEE_IOCTL_UUID_LEN);
> >>>> +
> >>>> + sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
> >>>> + sess_arg.num_params = 1;
> >>>> +
> >>>> + param[0] = (struct tee_param) {
> >>>> + .attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> >>>> + .u.value.a = rproc_id,
> >>>> + };
> >>>> +
> >>>> + ret = tee_client_open_session(tee_rproc_ctx->tee_ctx, &sess_arg, param);
> >>>> + if (ret < 0 || sess_arg.ret != 0) {
> >>>> + dev_err(dev, "tee_client_open_session failed, err: %x\n", sess_arg.ret);
> >>>> + return ERR_PTR(-EINVAL);
> >>>> + }
> >>>> +
> >>>> + trproc->parent = dev;
> >>>> + trproc->rproc_id = rproc_id;
> >>>> + trproc->session_id = sess_arg.session;
> >>>> +
> >>>> + trproc->rproc = rproc;
> >>>> + rproc->tee_interface = trproc;
> >>>> +
> >>>> + list_add_tail(&trproc->node, &tee_rproc_ctx->sessions);
> >>>> +
> >>>> + return trproc;
> >>>
> >>> Once this function was called by a client, what prevents a user from unloading
> >>> the tee_remoteproc module and breaking everything?
> >>
> >> Good point! seems better toremove the module build capability
> >>
> >
> > I was thinking more along the lines of try_module_get() and module_put() to
> > avoid bloating the core.
> >
> >> Thanks,
> >> Arnaud
> >>
> >>>
> >>>> +}
> >>>> +EXPORT_SYMBOL_GPL(tee_rproc_register);
> >>>> +
> >>>> +int tee_rproc_unregister(struct tee_rproc *trproc)
> >>>> +{
> >>>
> >>> If you pass a struct_rproc instead of a struct tee_rproc there is no need for
> >>> tee_rproc::rproc, which is only ever used in this function.
> >>>
> >>>
> >>>> + struct rproc *rproc = trproc->rproc;
> >>>> + int ret;
> >>>> +
> >>>> + ret = tee_client_close_session(tee_rproc_ctx->tee_ctx, trproc->session_id);
> >>>> + if (ret < 0)
> >>>> + dev_err(trproc->parent, "tee_client_close_session failed, err: %x\n", ret);
> >>>> +
> >>>> + list_del(&trproc->node);
> >>>> + rproc->tee_interface = NULL;
> >>>> +
> >>>> + return ret;
> >>>> +}
> >>>> +EXPORT_SYMBOL_GPL(tee_rproc_unregister);
> >>>> +
> >>>> +static int tee_rproc_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
> >>>> +{
> >>>> + /* Today we support only the OP-TEE, could be extend to other tees */
> >>>> + return (ver->impl_id == TEE_IMPL_ID_OPTEE);
> >>>> +}
> >>>> +
> >>>> +static int tee_rproc_probe(struct device *dev)
> >>>> +{
> >>>> + struct tee_context *tee_ctx;
> >>>> + int ret;
> >>>> +
> >>>> + /* Open context with TEE driver */
> >>>> + tee_ctx = tee_client_open_context(NULL, tee_rproc_ctx_match, NULL, NULL);
> >>>> + if (IS_ERR(tee_ctx))
> >>>> + return PTR_ERR(tee_ctx);
> >>>> +
> >>>> + tee_rproc_ctx = devm_kzalloc(dev, sizeof(*tee_ctx), GFP_KERNEL);
> >>>> + if (!tee_rproc_ctx) {
> >>>> + ret = -ENOMEM;
> >>>> + goto err;
> >>>> + }
> >>>> +
> >>>> + tee_rproc_ctx->dev = dev;
> >>>> + tee_rproc_ctx->tee_ctx = tee_ctx;
> >>>> + INIT_LIST_HEAD(&tee_rproc_ctx->sessions);
> >>>> +
> >>>> + return 0;
> >>>> +err:
> >>>> + tee_client_close_context(tee_ctx);
> >>>> +
> >>>> + return ret;
> >>>> +}
> >>>> +
> >>>> +static int tee_rproc_remove(struct device *dev)
> >>>> +{
> >>>> + struct tee_rproc *entry, *tmp;
> >>>> +
> >>>> + list_for_each_entry_safe(entry, tmp, &tee_rproc_ctx->sessions, node) {
> >>>> + tee_client_close_session(tee_rproc_ctx->tee_ctx, entry->session_id);
> >>>> + list_del(&entry->node);
> >>>> + if (entry->rsc_table)
> >>>> + iounmap(entry->rsc_table);
> >>>> + kfree(entry);
> >>>> + }
> >>>> +
> >>>> + tee_client_close_context(tee_rproc_ctx->tee_ctx);
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +MODULE_DEVICE_TABLE(tee, stm32_tee_rproc_id_table);
> >>>> +
> >>>> +static struct tee_client_driver tee_rproc_fw_driver = {
> >>>> + .id_table = stm32_tee_rproc_id_table,
> >>>> + .driver = {
> >>>> + .name = KBUILD_MODNAME,
> >>>> + .bus = &tee_bus_type,
> >>>> + .probe = tee_rproc_probe,
> >>>> + .remove = tee_rproc_remove,
> >>>> + },
> >>>> +};
> >>>> +
> >>>> +static int __init tee_rproc_fw_mod_init(void)
> >>>> +{
> >>>> + return driver_register(&tee_rproc_fw_driver.driver);
> >>>> +}
> >>>> +
> >>>> +static void __exit tee_rproc_fw_mod_exit(void)
> >>>> +{
> >>>> + driver_unregister(&tee_rproc_fw_driver.driver);
> >>>> +}
> >>>> +
> >>>> +module_init(tee_rproc_fw_mod_init);
> >>>> +module_exit(tee_rproc_fw_mod_exit);
> >>>> +
> >>>> +MODULE_DESCRIPTION(" TEE remote processor control driver");
> >>>> +MODULE_LICENSE("GPL");
> >>>> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> >>>> index b4795698d8c2..8b678009e481 100644
> >>>> --- a/include/linux/remoteproc.h
> >>>> +++ b/include/linux/remoteproc.h
> >>>> @@ -503,6 +503,8 @@ enum rproc_features {
> >>>> RPROC_MAX_FEATURES,
> >>>> };
> >>>>
> >>>> +struct tee_rproc;
> >>>> +
> >>>> /**
> >>>> * struct rproc - represents a physical remote processor device
> >>>> * @node: list node of this rproc object
> >>>> @@ -545,6 +547,7 @@ enum rproc_features {
> >>>> * @cdev: character device of the rproc
> >>>> * @cdev_put_on_release: flag to indicate if remoteproc should be shutdown on @char_dev release
> >>>> * @features: indicate remoteproc features
> >>>> + * @tee_interface: pointer to the remoteproc tee context
> >>>> */
> >>>> struct rproc {
> >>>> struct list_head node;
> >>>> @@ -586,6 +589,7 @@ struct rproc {
> >>>> struct cdev cdev;
> >>>> bool cdev_put_on_release;
> >>>> DECLARE_BITMAP(features, RPROC_MAX_FEATURES);
> >>>> + struct tee_rproc *tee_interface;
> >>>> };
> >>>>
> >>>> /**
> >>>> diff --git a/include/linux/tee_remoteproc.h b/include/linux/tee_remoteproc.h
> >>>> new file mode 100644
> >>>> index 000000000000..571e47190d02
> >>>> --- /dev/null
> >>>> +++ b/include/linux/tee_remoteproc.h
> >>>> @@ -0,0 +1,112 @@
> >>>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> >>>> +/*
> >>>> + * Copyright(c) 2024 STMicroelectronics - All Rights Reserved
> >>>> + */
> >>>> +
> >>>> +#ifndef TEE_REMOTEPROC_H
> >>>> +#define TEE_REMOTEPROC_H
> >>>> +
> >>>> +#include <linux/tee_drv.h>
> >>>> +#include <linux/firmware.h>
> >>>> +#include <linux/remoteproc.h>
> >>>> +
> >>>> +struct rproc;
> >>>> +
> >>>> +/**
> >>>> + * struct tee_rproc - TEE remoteproc structure
> >>>> + * @node: Reference in list
> >>>> + * @rproc: Remoteproc reference
> >>>> + * @parent: Parent device
> >>>> + * @rproc_id: Identifier of the target firmware
> >>>> + * @session_id: TEE session identifier
> >>>> + * @rsc_table: Resource table virtual address.
> >>>> + */
> >>>> +struct tee_rproc {
> >>>> + struct list_head node;
> >>>> + struct rproc *rproc;
> >>>> + struct device *parent;
> >>>> + u32 rproc_id;
> >>>> + u32 session_id;
> >>>> + struct resource_table *rsc_table;
> >>>> +};
> >>>> +
> >>>> +#if IS_REACHABLE(CONFIG_TEE_REMOTEPROC)
> >>>> +
> >>>> +struct tee_rproc *tee_rproc_register(struct device *dev, struct rproc *rproc,
> >>>> + unsigned int rproc_id);
> >>>> +int tee_rproc_unregister(struct tee_rproc *trproc);
> >>>> +int tee_rproc_parse_fw(struct rproc *rproc, const struct firmware *fw);
> >>>> +int tee_rproc_load_fw(struct rproc *rproc, const struct firmware *fw);
> >>>> +struct resource_table *tee_rproc_get_loaded_rsc_table(struct rproc *rproc, size_t *table_sz);
> >>>> +struct resource_table *tee_rproc_find_loaded_rsc_table(struct rproc *rproc,
> >>>> + const struct firmware *fw);
> >>>> +int tee_rproc_start(struct rproc *rproc);
> >>>> +int tee_rproc_stop(struct rproc *rproc);
> >>>> +
> >>>> +#else
> >>>> +
> >>>> +static inline struct tee_rproc *tee_rproc_register(struct device *dev, struct rproc *rproc,
> >>>> + unsigned int rproc_id)
> >>>> +{
> >>>> + return ERR_PTR(-ENODEV);
> >>>> +}
> >>>> +
> >>>> +static int tee_rproc_parse_fw(struct rproc *rproc, const struct firmware *fw)
> >>>> +{
> >>>> + /* This shouldn't be possible */
> >>>> + WARN_ON(1);
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static inline int tee_rproc_unregister(struct tee_rproc *trproc)
> >>>> +{
> >>>> + /* This shouldn't be possible */
> >>>> + WARN_ON(1);
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static inline int tee_rproc_load_fw(struct rproc *rproc, const struct firmware *fw)
> >>>> +{
> >>>> + /* This shouldn't be possible */
> >>>> + WARN_ON(1);
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static inline int tee_rproc_start(struct rproc *rproc)
> >>>> +{
> >>>> + /* This shouldn't be possible */
> >>>> + WARN_ON(1);
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static inline int tee_rproc_stop(struct rproc *rproc)
> >>>> +{
> >>>> + /* This shouldn't be possible */
> >>>> + WARN_ON(1);
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static inline struct resource_table *
> >>>> +tee_rproc_get_loaded_rsc_table(struct rproc *rproc, size_t *table_sz)
> >>>> +{
> >>>> + /* This shouldn't be possible */
> >>>> + WARN_ON(1);
> >>>> +
> >>>> + return NULL;
> >>>> +}
> >>>> +
> >>>> +static inline struct resource_table *
> >>>> +tee_rproc_find_loaded_rsc_table(struct rproc *rproc, const struct firmware *fw)
> >>>> +{
> >>>> + /* This shouldn't be possible */
> >>>> + WARN_ON(1);
> >>>> +
> >>>> + return NULL;
> >>>> +}
> >>>> +#endif /* CONFIG_TEE_REMOTEPROC */
> >>>> +#endif /* TEE_REMOTEPROC_H */
> >>>> --
> >>>> 2.25.1
> >>>>

2024-04-03 07:06:02

by Arnaud POULIQUEN

[permalink] [raw]

Subject: Re: [PATCH v4 4/4] remoteproc: stm32: Add support of an OP-TEE TA to load the firmware

On 4/1/24 17:46, Mathieu Poirier wrote:
> On Fri, Mar 29, 2024 at 11:57:43AM +0100, Arnaud POULIQUEN wrote:
>>
>>
>> On 3/27/24 18:14, Mathieu Poirier wrote:
>>> On Tue, Mar 26, 2024 at 08:31:33PM +0100, Arnaud POULIQUEN wrote:
>>>>
>>>>
>>>> On 3/25/24 17:51, Mathieu Poirier wrote:
>>>>> On Fri, Mar 08, 2024 at 03:47:08PM +0100, Arnaud Pouliquen wrote:
>>>>>> The new TEE remoteproc device is used to manage remote firmware in a
>>>>>> secure, trusted context. The 'st,stm32mp1-m4-tee' compatibility is
>>>>>> introduced to delegate the loading of the firmware to the trusted
>>>>>> execution context. In such cases, the firmware should be signed and
>>>>>> adhere to the image format defined by the TEE.
>>>>>>
>>>>>> Signed-off-by: Arnaud Pouliquen <[email protected]>
>>>>>> ---
>>>>>> Updates from V3:
>>>>>> - remove support of the attach use case. Will be addressed in a separate
>>>>>> thread,
>>>>>> - add st_rproc_tee_ops::parse_fw ops,
>>>>>> - inverse call of devm_rproc_alloc()and tee_rproc_register() to manage cross
>>>>>> reference between the rproc struct and the tee_rproc struct in tee_rproc.c.
>>>>>> ---
>>>>>> drivers/remoteproc/stm32_rproc.c | 60 +++++++++++++++++++++++++++++---
>>>>>> 1 file changed, 56 insertions(+), 4 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
>>>>>> index 8cd838df4e92..13df33c78aa2 100644
>>>>>> --- a/drivers/remoteproc/stm32_rproc.c
>>>>>> +++ b/drivers/remoteproc/stm32_rproc.c
>>>>>> @@ -20,6 +20,7 @@
>>>>>> #include <linux/remoteproc.h>
>>>>>> #include <linux/reset.h>
>>>>>> #include <linux/slab.h>
>>>>>> +#include <linux/tee_remoteproc.h>
>>>>>> #include <linux/workqueue.h>
>>>>>>
>>>>>> #include "remoteproc_internal.h"
>>>>>> @@ -49,6 +50,9 @@
>>>>>> #define M4_STATE_STANDBY 4
>>>>>> #define M4_STATE_CRASH 5
>>>>>>
>>>>>> +/* Remote processor unique identifier aligned with the Trusted Execution Environment definitions */
>>>>>
>>>>> Why is this the case? At least from the kernel side it is possible to call
>>>>> tee_rproc_register() with any kind of value, why is there a need to be any
>>>>> kind of alignment with the TEE?
>>>>
>>>>
>>>> The use of the proc_id is to identify a processor in case of multi co-processors.
>>>>
>>>
>>> That is well understood.
>>>
>>>> For instance we can have a system with A DSP and a modem. We would use the same
>>>> TEE service, but
>>>
>>> That too.
>>>
>>>> the TEE driver will probably be different, same for the signature key.
>>>
>>> What TEE driver are we talking about here?
>>
>> In OP-TEE remoteproc frameork is divided in 2 or 3 layers:
>>
>> - the remoteproc Trusted Application (TA) [1] which is platform agnostic
>> - The remoteproc Pseudo Trusted Application (PTA) [2] which is platform
>> dependent and can rely on the proc ID to retrieve the context.
>> - the remoteproc driver (optional for some platforms) [3], which is in charge
>> of DT parsing and platform configuration.
>>
>
> That part makes sense.
>
>> Here TEE driver can be interpreted by remote PTA and/or platform driver.
>>
>
> I have to guess PTA means "Platform Trusted Application" but I have no
> guarantee, adding to the level of (already high) confusion brought on by this
> patchset.

As mentioned above, PTA is Pseudo Trusted Application. It is an interface
exposed by OP-TEE core to the OP-TEE application.
In this case PTA is used to implement the platform part.
If you need more details about the remoteproc framework in OP-TEE, there is a
link in the to a presentation in the cover letter.

>
>> [1]
>> https://elixir.bootlin.com/op-tee/latest/source/ta/remoteproc/src/remoteproc_core.c
>> [2]
>> https://elixir.bootlin.com/op-tee/latest/source/core/pta/stm32mp/remoteproc_pta.c
>> [3]
>> https://elixir.bootlin.com/op-tee/latest/source/core/drivers/remoteproc/stm32_remoteproc.c
>>
>>>
>>>> In such case the proc ID allows to identify the the processor you want to address.
>>>>
>>>
>>> That too is well understood, but there is no alignment needed with the TEE, i.e
>>> the TEE application is not expecting a value of '0'. We could set
>>> STM32_MP1_M4_PROC_ID to 0xDEADBEEF and things would work. This driver won't go
>>> anywhere for as long as it is not the case.
>>
>>
>> Here I suppose that you do not challenge the rproc_ID use in general, but for
>> the stm32mp1 platform as we have only one remote processor. I'm right?
>
> That is correct - I understand the need for an rproc_ID. The problem is with
> the comment that states that '0' is aligned with the TEE definitions, which in
> my head means hard coded value and a big red flag. What it should say is
> "aligned with the TEE device tree definition".
>
>>
>> In OP-TEE the check is done here:
>> https://elixir.bootlin.com/op-tee/latest/source/core/drivers/remoteproc/stm32_remoteproc.c#L64
>>
>> If driver does not register the proc ID an error is returned indicating that the
>> feature is not supported.
>>
>> In case of stm32mp1 yes we could consider it as useless as we have only one
>> remote proc.
>>
>> Nevertheless I can not guaranty that a customer will not add an external
>> companion processor that uses OP-TEE to authenticate the associated firmware. As
>> the trusted Application is the unique entry point. he will need the proc_id to
>> identify the target at PTA level.
>>
>> So from my point of view having a proc ID on stm32MP1 (and on stm32mp2 that will
>> reuse same driver) aligned between Linux and OP-TEE is useful.
>
> I agree, for as long as it is not hard coded. The way remote processors are
> discovered in the DT is perfectly acceptable, i.e the first remote processor is
> for application X, the second for application Y...
>
>>
>> That said using a TEE_REMOTEPROC_DEFAULT_ID is something that could be
>> more generic (for linux and OP-TEE). This ID could be reuse in the stm32mp
>> driver and platform drivers with an unique internal remote processor.
>>
>
> I can't find the definition of TEE_REMOTEPROC_DEFAULT_ID anywhere, something
> that doesn't help the confusion I referred to above.

The TEE_REMOTEPROC_DEFAULT_ID does not yet exist; it is a proposal.

Nevertheless I also had in mind the addition of a "proc ID" property in the DT.
I will proceed in this way

I think I now have all the information needed to prepare a new revision.
Thanks for the time passed on this series and your advises
Regards,
Arnaud

>
>> It that solution would be ok for you?
>>
>> Regards,
>> Arnaud
>>
>>
>>>
>>>>
>>>>>
>>>>>> +#define STM32_MP1_M4_PROC_ID 0
>>>>>> +
>>>>>> struct stm32_syscon {
>>>>>> struct regmap *map;
>>>>>> u32 reg;
>>>>>> @@ -257,6 +261,19 @@ static int stm32_rproc_release(struct rproc *rproc)
>>>>>> return 0;
>>>>>> }
>>>>>>
>>>>>> +static int stm32_rproc_tee_stop(struct rproc *rproc)
>>>>>> +{
>>>>>> + int err;
>>>>>> +
>>>>>> + stm32_rproc_request_shutdown(rproc);
>>>>>> +
>>>>>> + err = tee_rproc_stop(rproc);
>>>>>> + if (err)
>>>>>> + return err;
>>>>>> +
>>>>>> + return stm32_rproc_release(rproc);
>>>>>> +}
>>>>>> +
>>>>>> static int stm32_rproc_prepare(struct rproc *rproc)
>>>>>> {
>>>>>> struct device *dev = rproc->dev.parent;
>>>>>> @@ -693,8 +710,19 @@ static const struct rproc_ops st_rproc_ops = {
>>>>>> .get_boot_addr = rproc_elf_get_boot_addr,
>>>>>> };
>>>>>>
>>>>>> +static const struct rproc_ops st_rproc_tee_ops = {
>>>>>> + .prepare = stm32_rproc_prepare,
>>>>>> + .start = tee_rproc_start,
>>>>>> + .stop = stm32_rproc_tee_stop,
>>>>>> + .kick = stm32_rproc_kick,
>>>>>> + .load = tee_rproc_load_fw,
>>>>>> + .parse_fw = tee_rproc_parse_fw,
>>>>>> + .find_loaded_rsc_table = tee_rproc_find_loaded_rsc_table,
>>>>>> +};
>>>>>> +
>>>>>> static const struct of_device_id stm32_rproc_match[] = {
>>>>>> - { .compatible = "st,stm32mp1-m4" },
>>>>>> + {.compatible = "st,stm32mp1-m4",},
>>>>>> + {.compatible = "st,stm32mp1-m4-tee",},
>>>>>> {},
>>>>>> };
>>>>>> MODULE_DEVICE_TABLE(of, stm32_rproc_match);
>>>>>> @@ -853,6 +881,7 @@ static int stm32_rproc_probe(struct platform_device *pdev)
>>>>>> struct device *dev = &pdev->dev;
>>>>>> struct stm32_rproc *ddata;
>>>>>> struct device_node *np = dev->of_node;
>>>>>> + struct tee_rproc *trproc = NULL;
>>>>>> struct rproc *rproc;
>>>>>> unsigned int state;
>>>>>> int ret;
>>>>>> @@ -861,9 +890,26 @@ static int stm32_rproc_probe(struct platform_device *pdev)
>>>>>> if (ret)
>>>>>> return ret;
>>>>>>
>>>>>> - rproc = devm_rproc_alloc(dev, np->name, &st_rproc_ops, NULL, sizeof(*ddata));
>>>>>> - if (!rproc)
>>>>>> - return -ENOMEM;
>>>>>> + if (of_device_is_compatible(np, "st,stm32mp1-m4-tee")) {
>>>>>> + /*
>>>>>> + * Delegate the firmware management to the secure context.
>>>>>> + * The firmware loaded has to be signed.
>>>>>> + */
>>>>>> + rproc = devm_rproc_alloc(dev, np->name, &st_rproc_tee_ops, NULL, sizeof(*ddata));
>>>>>> + if (!rproc)
>>>>>> + return -ENOMEM;
>>>>>> +
>>>>>> + trproc = tee_rproc_register(dev, rproc, STM32_MP1_M4_PROC_ID);
>>>>>> + if (IS_ERR(trproc)) {
>>>>>> + dev_err_probe(dev, PTR_ERR(trproc),
>>>>>> + "signed firmware not supported by TEE\n");
>>>>>> + return PTR_ERR(trproc);
>>>>>> + }
>>>>>> + } else {
>>>>>> + rproc = devm_rproc_alloc(dev, np->name, &st_rproc_ops, NULL, sizeof(*ddata));
>>>>>> + if (!rproc)
>>>>>> + return -ENOMEM;
>>>>>> + }
>>>>>>
>>>>>> ddata = rproc->priv;
>>>>>>
>>>>>> @@ -915,6 +961,9 @@ static int stm32_rproc_probe(struct platform_device *pdev)
>>>>>> dev_pm_clear_wake_irq(dev);
>>>>>> device_init_wakeup(dev, false);
>>>>>> }
>>>>>> + if (trproc)
>>>>>
>>>>> if (rproc->tee_interface)
>>>>>
>>>>>
>>>>> I am done reviewing this set.
>>>>
>>>> Thank for your review!
>>>> Arnaud
>>>>
>>>>>
>>>>> Thanks,
>>>>> Mathieu
>>>>>
>>>>>> + tee_rproc_unregister(trproc);
>>>>>> +
>>>>>> return ret;
>>>>>> }
>>>>>>
>>>>>> @@ -935,6 +984,9 @@ static void stm32_rproc_remove(struct platform_device *pdev)
>>>>>> dev_pm_clear_wake_irq(dev);
>>>>>> device_init_wakeup(dev, false);
>>>>>> }
>>>>>> + if (rproc->tee_interface)
>>>>>> + tee_rproc_unregister(rproc->tee_interface);
>>>>>> +
>>>>>> }
>>>>>>
>>>>>> static int stm32_rproc_suspend(struct device *dev)
>>>>>> --
>>>>>> 2.25.1
>>>>>>