On Mon, Jun 16, 2025 at 09:55:26AM +0200, 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 the secure part, this driver offers a client interface to load firmware
> by the secure part.
> This firmware could be authenticated by the secure trusted application.
>
> A specificity of the implementation is that the firmware has to be
> authenticated and optionally decrypted to access the resource table.
>
> Consequently, the boot sequence is:
>
> 1) rproc_parse_fw --> rproc_tee_parse_fw
> remoteproc TEE:
> - Requests the TEE application to authenticate and load the firmware
> in the remote processor memories.
> - Requests the TEE application for the address of the resource table.
> - Creates a copy of the resource table stored in rproc->cached_table.
>
> 2) rproc_load_segments --> rproc_tee_load_fw
> remoteproc TEE:
> - Requests the TEE application to load the firmware. Nothing is done
> at the TEE application as the firmware is already loaded.
> - In case of recovery, the TEE application has to reload the firmware.
>
> 3) rproc_tee_get_loaded_rsc_table
> remoteproc TEE requests the TEE application for the address of the
> resource table.
>
> 4) rproc_start --> rproc_tee_start
> - Requests the TEE application to start the remote processor.
>
> The shutdown sequence is:
>
> 5) rproc_stop --> rproc_tee_stop
> - Requests the TEE application to stop the remote processor.
>
> 6) rproc_tee_release_fw
> This function is used to request the TEE application to perform actions
> to return to the initial state on stop or on error during the boot
> sequence.
>
I thought these patches were ready to go in now, but as I went through
them in detail once more the locking in this patch caught my attention.
And the kernel-doc is not good.
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliq...@foss.st.com>
> ---
> Updates vs previous version:
> Fix warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
Please keep the full change history in each version of your series, it
makes it easier to review.
> ---
> drivers/remoteproc/Kconfig | 10 +
> drivers/remoteproc/Makefile | 1 +
> drivers/remoteproc/remoteproc_tee.c | 620 ++++++++++++++++++++++++++++
> include/linux/remoteproc_tee.h | 90 ++++
> 4 files changed, 721 insertions(+)
> create mode 100644 drivers/remoteproc/remoteproc_tee.c
> create mode 100644 include/linux/remoteproc_tee.h
>
> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> index 83962a114dc9..e39265d249d9 100644
> --- a/drivers/remoteproc/Kconfig
> +++ b/drivers/remoteproc/Kconfig
> @@ -23,6 +23,16 @@ config REMOTEPROC_CDEV
>
> It's safe to say N if you don't want to use this interface.
>
> +config REMOTEPROC_TEE
> + bool "Remoteproc support by a TEE application"
> + depends on OPTEE
> + help
> + Support a remote processor that is managed by an application running
> in a Trusted
> + Execution Environment (TEE). This application is responsible for
> loading the remote
> + processor firmware image and managing its lifecycle.
> +
> + It's safe to say N if the remote processor is not managed by a TEE.
> +
> config IMX_REMOTEPROC
> tristate "i.MX remoteproc support"
> depends on ARCH_MXC
> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> index 1c7598b8475d..a1a5201982d4 100644
> --- a/drivers/remoteproc/Makefile
> +++ b/drivers/remoteproc/Makefile
> @@ -11,6 +11,7 @@ remoteproc-y +=
> remoteproc_sysfs.o
> remoteproc-y += remoteproc_virtio.o
> remoteproc-y += remoteproc_elf_loader.o
> obj-$(CONFIG_REMOTEPROC_CDEV) += remoteproc_cdev.o
> +obj-$(CONFIG_REMOTEPROC_TEE) += remoteproc_tee.o
> obj-$(CONFIG_IMX_REMOTEPROC) += imx_rproc.o
> obj-$(CONFIG_IMX_DSP_REMOTEPROC) += imx_dsp_rproc.o
> obj-$(CONFIG_INGENIC_VPU_RPROC) += ingenic_rproc.o
> diff --git a/drivers/remoteproc/remoteproc_tee.c
> b/drivers/remoteproc/remoteproc_tee.c
> new file mode 100644
> index 000000000000..6b610dfa1ee1
> --- /dev/null
> +++ b/drivers/remoteproc/remoteproc_tee.c
> @@ -0,0 +1,620 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) STMicroelectronics 2024
Bump the year, please.
> + * Author: Arnaud Pouliquen <arnaud.pouliq...@foss.st.com>
> + */
> +
> +#include <linux/export.h>
> +#include <linux/firmware.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/remoteproc.h>
> +#include <linux/remoteproc_tee.h>
> +#include <linux/slab.h>
> +#include <linux/tee_drv.h>
> +
> +#define MAX_TEE_PARAM_ARRAY_MEMBER 4
> +
> +/*
> + * Authentication and load of the firmware image in the remote processor
> memories by the TEE.
> + * After this step the firmware is loaded in destination memories, which can
> then be locked to
> + * prevent access by Linux.
Wrap lines at 80 characters, if it improves readability you can use up
to 100.
> + *
> + * [in] params[0].value.a: remote processor identifier
Here "[in]" is followed by 2 spaces.
> + * [in] params[1].memref: buffer containing a temporary copy of
> the signed image to load.
Here "[in]" is followed by one tab and one space.
> + */
> +#define TA_RPROC_FW_CMD_LOAD_FW 1
> +
> +/*
> + * Start the remote processor by the TEE
> + *
> + * [in] params[0].value.a: remote processor identifier
> + */
> +#define TA_RPROC_FW_CMD_START 2
> +
> +/*
> + * Stop the remote processor by the TEE
> + *
> + * [in] params[0].value.a: remote processor identifier
> + */
> +#define TA_RPROC_FW_CMD_STOP 3
> +
> +/*
> + * Return the address of the resource table, or 0 if not found.
> + *
> + * [in] params[0].value.a: remote processor identifier
> + * [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
> +
> +/*
> + * Release remote processor firmware images and associated resources.
> + * This command should be used in case an error occurs between the loading of
> + * the firmware images (TA_RPROC_CMD_LOAD_FW) and the starting of the remote
> + * processor (TA_RPROC_CMD_START_FW) or after stopping the remote processor
> + * to release associated resources (TA_RPROC_CMD_STOP_FW).
> + *
> + * [in] params[0].value.a: Unique 32-bit remote processor identifier
The other 4 commands are defined with "remote processor identifier" as
the first parameter, but this command needs a "unique 32-bit" such
value?
> + */
> +#define TA_RPROC_CMD_RELEASE_FW 6
> +
> +struct rproc_tee_context {
> + struct list_head sessions;
> + struct tee_context *tee_ctx;
> + struct device *dev;
> +};
> +
> +/**
> + * struct rproc_tee - TEE remoteproc structure
> + * @node: Reference in list
> + * @rproc: Remoteproc reference
> + * @rproc_id: Identifier of the target firmware
Everywhere else you say this identifies the remote processor...
> + * @session_id: TEE session identifier
> + */
> +struct rproc_tee {
> + struct list_head node;
> + struct rproc *rproc;
> + u32 rproc_id;
> + u32 session_id;
> +};
> +
> +static struct rproc_tee_context rproc_tee_ctx;
> +static DEFINE_SPINLOCK(ctx_lock);
> +
> +static struct rproc_tee *rproc_to_trproc(struct rproc *rproc)
> +{
> + struct rproc_tee *trproc;
> +
> + list_for_each_entry(trproc, &rproc_tee_ctx.sessions, node)
You make sure to only modify this list under lock, but here you're
traversing the list without consideration for concurrency.
> + if (trproc->rproc == rproc)
> + return trproc;
> +
> + return NULL;
> +}
> +
> +static void rproc_tee_prepare_args(struct rproc_tee *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_ARRAY_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,
> + };
> +}
> +
> +/**
> + * rproc_tee_release_fw - Release the firmware for a TEE-based remote
> processor
> + *
> + * This function invokes the TA_RPROC_CMD_RELEASE_FW TEE client function to
> release the firmware.
> + * It should only be called when the remoteproc state is RPROC_OFFLINE or
> RPROC_DETACHED.
> + * The function requests the TEE remoteproc application to release the
> firmware loaded by
> + * rproc_tee_load_fw(). The request is ignored if the rproc state is
> RPROC_DETACHED as the
> + * remote processor is still running.
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + */
> +void rproc_tee_release_fw(struct rproc *rproc)
> +{
> + struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> + struct rproc_tee *trproc = rproc_to_trproc(rproc);
> + struct tee_ioctl_invoke_arg arg;
> + int ret;
> +
> + if (!rproc_tee_ctx.dev)
In the (unlikely) event that the tee device is removed this is racy. On
the other hand, the only thing you seem to rely on this "dev" for is
error prints?
> + return;
> +
> + if (!trproc)
> + return;
> +
> + /*
> + * If the remote processor state is RPROC_DETACHED, just ignore the
> + * request, as the remote processor is still running.
> + */
> + if (rproc->state == RPROC_DETACHED)
> + return;
> +
> + if (rproc->state != RPROC_OFFLINE) {
> + dev_err(rproc_tee_ctx.dev, "unexpected rproc state: %d\n",
> rproc->state);
> + return;
> + }
> +
> + rproc_tee_prepare_args(trproc, TA_RPROC_CMD_RELEASE_FW, &arg, param, 0);
> +
> + ret = tee_client_invoke_func(rproc_tee_ctx.tee_ctx, &arg, param);
> + if (ret < 0 || arg.ret != 0) {
> + dev_err(rproc_tee_ctx.dev,
> + "TA_RPROC_CMD_RELEASE_FW invoke failed TEE err: %#x,
> ret:%d\n",
> + arg.ret, ret);
> + ret = -EIO;
ret isn't returned, so there's no reason to assign it here.
> + }
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_release_fw);
> +
> +/**
> + * rproc_tee_load_fw - Load firmware from TEE application
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and
> size
> + *
> + * This function invokes the TA_RPROC_FW_CMD_LOAD_FW TEE client function to
> load the firmware.
> + * It registers the fw->data as a shared memory region with the TEE, and
> request the TEE to load
> + * the firmware. This function can be called twice during the remote
> processor boot, considering
> + * that the TEE application ignores the command if the firmware is already
> loaded.
"can be called twice"? How does this relate to the TEE application
ignoring the command? How does the client know if the application
ignored it?
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and
> size
https://docs.kernel.org/doc-guide/kernel-doc.html#function-documentation
says function name should have () suffix. Then arguments (here you have
them twice). Then the longer description (for rproc_tee_release_fw() you
have this before arguments).
Also, please keep it within 80 characters.
> + *
> + * Return: 0 on success, or an error code on failure
> + */
> +int rproc_tee_load_fw(struct rproc *rproc, const struct firmware *fw)
> +{
> + struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> + struct rproc_tee *trproc = rproc_to_trproc(rproc);
> + struct tee_ioctl_invoke_arg arg;
> + struct tee_shm *fw_shm;
> + int ret;
> +
> + if (!rproc_tee_ctx.dev)
> + return -ENODEV;
> +
> + if (!trproc)
> + return -EINVAL;
> +
> + fw_shm = tee_shm_register_kernel_buf(rproc_tee_ctx.tee_ctx, (void
> *)fw->data, fw->size);
> + if (IS_ERR(fw_shm))
> + return PTR_ERR(fw_shm);
> +
> + rproc_tee_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(rproc_tee_ctx.tee_ctx, &arg, param);
> + if (ret < 0 || arg.ret != 0) {
> + dev_err(rproc_tee_ctx.dev,
> + "TA_RPROC_FW_CMD_LOAD_FW invoke failed TEE err: %#x,
> ret:%d\n",
> + arg.ret, ret);
> + if (!ret)
> + ret = -EIO;
If ret == 0 and arg.ret == <some error>, then this function will print
an error to the log and return success (0). Same with many of the other
functions where you have copy pasted this.
> + }
> +
> + tee_shm_free(fw_shm);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_load_fw);
> +
> +static int rproc_tee_get_loaded_rsc_table(struct rproc *rproc, phys_addr_t
> *rsc_pa,
> + size_t *table_sz)
> +{
> + struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> + struct rproc_tee *trproc = rproc_to_trproc(rproc);
> + struct tee_ioctl_invoke_arg arg;
> + int ret;
> +
> + if (!rproc_tee_ctx.dev)
> + return -ENODEV;
> +
> + if (!trproc)
> + return -EINVAL;
> +
> + rproc_tee_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(rproc_tee_ctx.tee_ctx, &arg, param);
> + if (ret < 0 || arg.ret != 0) {
> + dev_err(rproc_tee_ctx.dev,
> + "TA_RPROC_FW_CMD_GET_RSC_TABLE invoke failed TEE err:
> %#x, ret:%d\n",
> + arg.ret, ret);
> + return -EIO;
> + }
> +
> + *table_sz = param[2].u.value.a;
What happened to .b?
> +
> + if (*table_sz)
> + *rsc_pa = param[1].u.value.a;
Ditto
> + else
> + *rsc_pa = 0;
> +
> + return 0;
> +}
> +
> +/**
> + * rproc_tee_parse_fw - Get the resource table from TEE application
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and
> size
> + *
> + * This function retrieves the loaded resource table and creates a
> cached_table copy. Since the
> + * firmware image is signed and potentially encrypted, the firmware must be
> loaded first to
> + * access the loaded resource table.
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and
> size
Duplicated arguments list...
> + *
> + * Return: 0 on success, or an error code on failure
> + */
> +int rproc_tee_parse_fw(struct rproc *rproc, const struct firmware *fw)
> +{
> + phys_addr_t rsc_table;
> + void __iomem *rsc_va;
> + size_t table_sz;
> + int ret;
> +
> + if (!rproc)
> + return -EINVAL;
> +
> + /* We need first to Load the firmware, to be able to get the resource
> table. */
> + ret = rproc_tee_load_fw(rproc, fw);
> + if (ret)
> + return ret;
> +
> + ret = rproc_tee_get_loaded_rsc_table(rproc, &rsc_table, &table_sz);
> + if (ret)
> + goto release_fw;
> +
> + /*
> + * We assume here that the memory mapping is the same between the TEE
> and Linux kernel
> + * contexts. Else a new TEE remoteproc service could be needed to get a
> copy of the
> + * resource table
> + */
> + rsc_va = ioremap_wc(rsc_table, table_sz);
You're using tee_shm for transferring the image, you don't allow Linux
access to any part of the firmware (which is the reason why you need to
load the segments in rproc_parse_fw())...
So just out of curiosity, why is the resource table passed back to Linux
using a ioremap of some random/undefined chunk of memory?
> + if (!rsc_va) {
> + dev_err(rproc_tee_ctx.dev, "Unable to map memory region:
> %pa+%zx\n",
> + &rsc_table, table_sz);
> + ret = -ENOMEM;
> + goto release_fw;
> + }
> +
> + /*
> + * Create a copy of the resource table to have the same behavior as the
> ELF loader.
> + * This cached table will be used by the remoteproc core after the
> remoteproc stops
> + * to free resources and for crash recovery to reapply the settings.
> + * The cached table will be freed by the remoteproc core.
> + */
> + rproc->cached_table = kmemdup((__force void *)rsc_va, table_sz,
> GFP_KERNEL);
Is rsc_va DDR? And if so, wouldn't memremap() be a more accurate choice
above. If not, why isn't this kzalloc() + memcpy_fromio()?
> + iounmap(rsc_va);
> +
> + if (!rproc->cached_table) {
> + ret = -ENOMEM;
> + goto release_fw;
> + }
> +
> + rproc->table_ptr = rproc->cached_table;
> + rproc->table_sz = table_sz;
> +
> + return 0;
> +
> +release_fw:
> + rproc_tee_release_fw(rproc);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_parse_fw);
> +
> +/**
> + * rproc_tee_find_loaded_rsc_table - Find the loaded resource table loaded
> by the TEE application
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and
> size
> + *
> + * This function retrieves the physical address and size of the resource
> table loaded by the TEE
> + * application.
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and
> size
More argument duplication.
> + *
> + * Return: pointer to the resource table if found, or NULL if not found or
> size is 0
> + */
> +struct resource_table *rproc_tee_find_loaded_rsc_table(struct rproc *rproc,
> + const struct firmware
> *fw)
> +{
> + phys_addr_t rsc_table;
> + size_t table_sz;
> + int ret;
> +
> + ret = rproc_tee_get_loaded_rsc_table(rproc, &rsc_table, &table_sz);
> + if (ret)
> + return NULL;
> +
> + rproc->table_sz = table_sz;
> + if (!table_sz)
> + return NULL;
> +
> + /*
> + * At this step the memory area that contains the resource table should
> have been registered
> + * by the remote proc platform driver and allocated by
> rproc_alloc_registered_carveouts().
> + */
> + return (struct resource_table *)rproc_pa_to_va(rproc, rsc_table,
> table_sz, NULL);
rproc_pa_to_va() return type is void *, do you really need this explicit
typecast?
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_find_loaded_rsc_table);
> +
> +/**
> + * rproc_tee_start - Request the TEE application to start the remote
> processor
> + *
> + * This function invokes the TA_RPROC_FW_CMD_START command to start the
> remote processor.
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
kernel-doc ordering...
> + *
> + * Return: Returns 0 on success, -EINVAL or -EIO on failure
> + */
> +int rproc_tee_start(struct rproc *rproc)
> +{
> + struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> + struct rproc_tee *trproc = rproc_to_trproc(rproc);
> + struct tee_ioctl_invoke_arg arg;
> + int ret = 0;
First access of ret is an assignment, no need to zero-initialize it
here.
> +
> + if (!trproc)
> + return -EINVAL;
There's an inconsistency in that rproc_tee_ctx.dev is used without first
checking that it's valid in this function...
> +
> + rproc_tee_prepare_args(trproc, TA_RPROC_FW_CMD_START, &arg, param, 0);
> +
> + ret = tee_client_invoke_func(rproc_tee_ctx.tee_ctx, &arg, param);
> + if (ret < 0 || arg.ret != 0) {
> + dev_err(rproc_tee_ctx.dev,
> + "TA_RPROC_FW_CMD_START invoke failed TEE err: %#x,
> ret:%d\n", arg.ret, ret);
> + if (!ret)
> + return -EIO;
Why not assigning ret and falling through, like in most other functions?
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_start);
> +
> +/**
> + * rproc_tee_stop - Request the TEE application to start the remote processor
> + *
> + * This function invokes the TA_RPROC_FW_CMD_STOP command to stop the remote
> processor.
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + *
> + * Return: Returns 0 on success, -EINVAL or -EIO on failure
> + */
> +int rproc_tee_stop(struct rproc *rproc)
> +{
> + struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> + struct rproc_tee *trproc = rproc_to_trproc(rproc);
> + struct tee_ioctl_invoke_arg arg;
> + int ret;
> +
> + if (!trproc)
> + return -EINVAL;
> +
> + rproc_tee_prepare_args(trproc, TA_RPROC_FW_CMD_STOP, &arg, param, 0);
> +
> + ret = tee_client_invoke_func(rproc_tee_ctx.tee_ctx, &arg, param);
> + if (ret < 0 || arg.ret != 0) {
> + dev_err(rproc_tee_ctx.dev,
> + "TA_RPROC_FW_CMD_STOP invoke failed TEE err: %#x,
> ret:%d\n", arg.ret, ret);
> + if (!ret)
> + ret = -EIO;
> + }
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_stop);
> +
> +static const struct tee_client_device_id rproc_tee_id_table[] = {
> + {UUID_INIT(0x80a4c275, 0x0a47, 0x4905, 0x82, 0x85, 0x14, 0x86, 0xa9,
> 0x77, 0x1a, 0x08)},
> + {}
> +};
> +
> +/**
> + * rproc_tee_register - Register a remote processor controlled by a TEE
> application.
> + *
> + * This function registers a remote processor that will be managed by a TEE
> application,by opening
> + * a session with the TEE client.
> + *
> + * @dev: Pointer to client rproc device
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @rproc_id: ID of the remote processor
> + *
> + * Return: Returns 0 on success, or an error code on failure
> + */
> +int rproc_tee_register(struct device *dev, struct rproc *rproc, unsigned int
> rproc_id)
> +{
> + struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> + struct tee_ioctl_open_session_arg sess_arg;
> + struct tee_client_device *tee_device;
> + struct rproc_tee *trproc;
> + struct device_link *link;
> + int ret;
> +
> + spin_lock(&ctx_lock);
Why is this a spin_lock?
To my understanding the purpose of ctx_lock is to ensure mutual
exclusion of access to rproc_tee_ctx, but this doesn't look like it's
done from a context that isn't able to tolerate a mutex.
In particular during boot, if you have multiple remoteprocs being
registred, you're going to waste precious CPU cycles just spinning here.
And if it is a spinlock because you might enter here from some interrupt
context, how do you ensure this won't deadlock?
> + /*
> + * 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 (!rproc_tee_ctx.dev) {
> + ret = -EPROBE_DEFER;
> + goto out;
> + }
> +
> + trproc = kzalloc(sizeof(*trproc), GFP_KERNEL);
> + if (!trproc) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + tee_device = to_tee_client_device(rproc_tee_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,
> + };
I'm not familiar with the details of the tee calling convention, but do
you really need 4 entries in the param array and if so, would it make
sense to zero-initialize the other elements - like you do in all other
functions?
> +
> + ret = tee_client_open_session(rproc_tee_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);
> + ret = -EINVAL;
> + goto free_tproc;
> + }
> +
> + trproc->rproc_id = rproc_id;
> + trproc->session_id = sess_arg.session;
> +
> + trproc->rproc = rproc;
> +
> + /* Create device link between the rproc device and the TEE device */
This comment would be more useful if it documented why the link is
created - the fact that a link is added between the two devices can be
read on the next line...
> + link = device_link_add(dev, rproc_tee_ctx.dev,
> DL_FLAG_AUTOREMOVE_CONSUMER);
> + if (!link) {
> + ret = -ENOMEM;
> + goto close_tee;
> + }
> + list_add_tail(&trproc->node, &rproc_tee_ctx.sessions);
> +
> + goto out;
Please don't use goto to skip over the error handling. ret is going to
be 0 here, so unlock and return 0 here to make it clear that this is the
point of successful return.
> +
> +close_tee:
> + if (tee_client_close_session(rproc_tee_ctx.tee_ctx, trproc->session_id))
> + dev_err(rproc_tee_ctx.dev, "tee_client_close_session failed\n");
> +free_tproc:
> + kfree(trproc);
> +out:
> + spin_unlock(&ctx_lock);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_register);
> +
> +/**
> + * rproc_tee_unregister - Register a remote processor controlled by a TEE
> application.
> + *
> + * This function unregisters a remote processor previously registered by the
> rproc_tee_register()
> + * function.
> + *
> + * @dev: Pointer to client rproc device
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + *
> + * Return: Returns 0 on success, or an error code on failure
> + */
> +int rproc_tee_unregister(struct device *dev, struct rproc *rproc)
> +{
> + struct rproc_tee *trproc = rproc_to_trproc(rproc);
> + int ret;
> +
> + if (!trproc)
> + return -EINVAL;
> +
> + spin_lock(&ctx_lock);
This lock is taken after you have traversed the rproc_tee_ctx.session
list in a racy fashion.
> +
> + ret = tee_client_close_session(rproc_tee_ctx.tee_ctx,
> trproc->session_id);
> + if (ret < 0)
> + dev_err(rproc_tee_ctx.dev, "tee_client_close_session failed,
> err: %#x\n", ret);
> +
> + spin_unlock(&ctx_lock);
> +
> + list_del(&trproc->node);
Although, I might misunderstand your locking scheme, because here you're
modifying the sessions list immediately after leaving the mutual
exclusion region?
> + kfree(trproc);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_unregister);
> +
> +static int rproc_tee_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 rproc_tee_probe(struct device *dev)
> +{
> + struct tee_context *tee_ctx;
> +
> + /* Open context with TEE driver */
> + tee_ctx = tee_client_open_context(NULL, rproc_tee_ctx_match, NULL,
> NULL);
> + if (IS_ERR(tee_ctx))
> + return PTR_ERR(tee_ctx);
> +
> + spin_lock(&ctx_lock);
> + rproc_tee_ctx.dev = dev;
> + rproc_tee_ctx.tee_ctx = tee_ctx;
> + INIT_LIST_HEAD(&rproc_tee_ctx.sessions);
> + spin_unlock(&ctx_lock);
> +
> + return 0;
> +}
> +
> +static int rproc_tee_remove(struct device *dev)
> +{
> + spin_lock(&ctx_lock);
> + tee_client_close_context(rproc_tee_ctx.tee_ctx);
> + rproc_tee_ctx.dev = NULL;
> + rproc_tee_ctx.tee_ctx = NULL;
> + spin_unlock(&ctx_lock);
> +
> + return 0;
> +}
> +
> +MODULE_DEVICE_TABLE(tee, rproc_tee_id_table);
> +
> +static struct tee_client_driver rproc_tee_fw_driver = {
> + .id_table = rproc_tee_id_table,
> + .driver = {
> + .name = KBUILD_MODNAME,
> + .bus = &tee_bus_type,
> + .probe = rproc_tee_probe,
> + .remove = rproc_tee_remove,
> + },
> +};
> +
> +static int __init rproc_tee_fw_mod_init(void)
> +{
> + return driver_register(&rproc_tee_fw_driver.driver);
> +}
> +
> +static void __exit rproc_tee_fw_mod_exit(void)
> +{
> + driver_unregister(&rproc_tee_fw_driver.driver);
> +}
> +
> +module_init(rproc_tee_fw_mod_init);
> +module_exit(rproc_tee_fw_mod_exit);
> +
> +MODULE_DESCRIPTION(" remote processor TEE module");
Why is there a space in the start of the description?
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/remoteproc_tee.h b/include/linux/remoteproc_tee.h
> new file mode 100644
> index 000000000000..659bd77a4f12
> --- /dev/null
> +++ b/include/linux/remoteproc_tee.h
> @@ -0,0 +1,90 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright(c) 2024 STMicroelectronics
Year?
> + */
> +
> +#ifndef REMOTEPROC_TEE_H
> +#define REMOTEPROC_TEE_H
> +
> +#include <linux/tee_drv.h>
> +#include <linux/firmware.h>
> +#include <linux/remoteproc.h>
> +
> +struct rproc;
> +struct rproc_tee;
rproc_tee is not used in the API, so there shouldn't be a need for
forward declaring it.
struct rproc is defined in linux/remoteproc.h, so that should be fine to
omit as well.
> +
> +#if IS_ENABLED(CONFIG_REMOTEPROC_TEE)
> +
> +int rproc_tee_register(struct device *dev, struct rproc *rproc, unsigned int
> rproc_id);
> +int rproc_tee_unregister(struct device *dev, struct rproc *rproc);
> +int rproc_tee_parse_fw(struct rproc *rproc, const struct firmware *fw);
> +int rproc_tee_load_fw(struct rproc *rproc, const struct firmware *fw);
> +void rproc_tee_release_fw(struct rproc *rproc);
> +struct resource_table *rproc_tee_find_loaded_rsc_table(struct rproc *rproc,
> + const struct firmware
> *fw);
> +int rproc_tee_start(struct rproc *rproc);
> +int rproc_tee_stop(struct rproc *rproc);
> +
> +#else
> +
> +static inline int rproc_tee_register(struct device *dev, struct rproc
> *rproc, unsigned int rproc_id)
> +{
> + return -ENODEV;
> +}
> +
> +static inline int rproc_tee_parse_fw(struct rproc *rproc, const struct
> firmware *fw)
> +{
> + /* This shouldn't be possible */
> + WARN_ON(1);
> +
> + return 0;
> +}
> +
> +static inline int rproc_tee_unregister(struct device *dev, struct rproc
> *rproc)
> +{
> + /* This shouldn't be possible */
> + WARN_ON(1);
> +
> + return 0;
> +}
> +
> +static inline int rproc_tee_load_fw(struct rproc *rproc, const struct
> firmware *fw)
Double space after the ','
Regards,
Bjorn
> +{
> + /* This shouldn't be possible */
> + WARN_ON(1);
> +
> + return 0;
> +}
> +
> +static inline int rproc_tee_start(struct rproc *rproc)
> +{
> + /* This shouldn't be possible */
> + WARN_ON(1);
> +
> + return 0;
> +}
> +
> +static inline int rproc_tee_stop(struct rproc *rproc)
> +{
> + /* This shouldn't be possible */
> + WARN_ON(1);
> +
> + return 0;
> +}
> +
> +static inline void rproc_tee_release_fw(struct rproc *rproc)
> +{
> + /* This shouldn't be possible */
> + WARN_ON(1);
> +}
> +
> +static inline struct resource_table *
> +rproc_tee_find_loaded_rsc_table(struct rproc *rproc, const struct firmware
> *fw)
> +{
> + /* This shouldn't be possible */
> + WARN_ON(1);
> +
> + return NULL;
> +}
> +#endif /* CONFIG_REMOTEPROC_TEE */
> +#endif /* REMOTEPROC_TEE_H */
> --
> 2.25.1
>
