From c3dc99d13c0656190cd516101df8c9f3eb35ac43 Mon Sep 17 00:00:00 2001 From: Etienne Carriere Date: Mon, 16 Oct 2023 11:04:27 +0200 Subject: [PATCH] tee: optee: support tracking system threads Adds support in the OP-TEE driver to keep track of reserved system threads. The logic allows one OP-TEE thread to be reserved to TEE system sessions. The optee_cq_*() functions are updated to handle this if enabled, that is when TEE describes how many thread context it supports and when at least 1 session has registered as a system session (using tee_client_system_session()). For sake of simplicity, initialization of call queue management is factorized into new helper function optee_cq_init(). The SMC ABI part of the driver enables this tracking, but the FF-A ABI part does not. Co-developed-by: Jens Wiklander Co-developed-by: Sumit Garg Signed-off-by: Sumit Garg Signed-off-by: Etienne Carriere Reviewed-by: Sumit Garg Signed-off-by: Jens Wiklander --- drivers/tee/optee/call.c | 106 ++++++++++++++++++++++++++++++ drivers/tee/optee/ffa_abi.c | 3 +- drivers/tee/optee/optee_private.h | 20 ++++++ drivers/tee/optee/smc_abi.c | 16 ++++- 4 files changed, 141 insertions(+), 4 deletions(-) diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c index 42e478ac6ce103..6058e49a59758e 100644 --- a/drivers/tee/optee/call.c +++ b/drivers/tee/optee/call.c @@ -39,9 +39,29 @@ struct optee_shm_arg_entry { DECLARE_BITMAP(map, MAX_ARG_COUNT_PER_ENTRY); }; +void optee_cq_init(struct optee_call_queue *cq, int thread_count) +{ + mutex_init(&cq->mutex); + INIT_LIST_HEAD(&cq->waiters); + + /* + * If cq->total_thread_count is 0 then we're not trying to keep + * track of how many free threads we have, instead we're relying on + * the secure world to tell us when we're out of thread and have to + * wait for another thread to become available. + */ + cq->total_thread_count = thread_count; + cq->free_thread_count = thread_count; +} + void optee_cq_wait_init(struct optee_call_queue *cq, struct optee_call_waiter *w, bool sys_thread) { + unsigned int free_thread_threshold; + bool need_wait = false; + + memset(w, 0, sizeof(*w)); + /* * We're preparing to make a call to secure world. In case we can't * allocate a thread in secure world we'll end up waiting in @@ -60,8 +80,38 @@ void optee_cq_wait_init(struct optee_call_queue *cq, */ init_completion(&w->c); list_add_tail(&w->list_node, &cq->waiters); + w->sys_thread = sys_thread; + + if (cq->total_thread_count) { + if (sys_thread || !cq->sys_thread_req_count) + free_thread_threshold = 0; + else + free_thread_threshold = 1; + + if (cq->free_thread_count > free_thread_threshold) + cq->free_thread_count--; + else + need_wait = true; + } mutex_unlock(&cq->mutex); + + while (need_wait) { + optee_cq_wait_for_completion(cq, w); + mutex_lock(&cq->mutex); + + if (sys_thread || !cq->sys_thread_req_count) + free_thread_threshold = 0; + else + free_thread_threshold = 1; + + if (cq->free_thread_count > free_thread_threshold) { + cq->free_thread_count--; + need_wait = false; + } + + mutex_unlock(&cq->mutex); + } } void optee_cq_wait_for_completion(struct optee_call_queue *cq, @@ -83,6 +133,14 @@ static void optee_cq_complete_one(struct optee_call_queue *cq) { struct optee_call_waiter *w; + /* Wake a waiting system session if any, prior to a normal session */ + list_for_each_entry(w, &cq->waiters, list_node) { + if (w->sys_thread && !completion_done(&w->c)) { + complete(&w->c); + return; + } + } + list_for_each_entry(w, &cq->waiters, list_node) { if (!completion_done(&w->c)) { complete(&w->c); @@ -104,6 +162,8 @@ void optee_cq_wait_final(struct optee_call_queue *cq, /* Get out of the list */ list_del(&w->list_node); + cq->free_thread_count++; + /* Wake up one eventual waiting task */ optee_cq_complete_one(cq); @@ -119,6 +179,28 @@ void optee_cq_wait_final(struct optee_call_queue *cq, mutex_unlock(&cq->mutex); } +/* Count registered system sessions to reserved a system thread or not */ +static bool optee_cq_incr_sys_thread_count(struct optee_call_queue *cq) +{ + if (cq->total_thread_count <= 1) + return false; + + mutex_lock(&cq->mutex); + cq->sys_thread_req_count++; + mutex_unlock(&cq->mutex); + + return true; +} + +static void optee_cq_decr_sys_thread_count(struct optee_call_queue *cq) +{ + mutex_lock(&cq->mutex); + cq->sys_thread_req_count--; + /* If there's someone waiting, let it resume */ + optee_cq_complete_one(cq); + mutex_unlock(&cq->mutex); +} + /* Requires the filpstate mutex to be held */ static struct optee_session *find_session(struct optee_context_data *ctxdata, u32 session_id) @@ -361,6 +443,27 @@ int optee_open_session(struct tee_context *ctx, return rc; } +int optee_system_session(struct tee_context *ctx, u32 session) +{ + struct optee *optee = tee_get_drvdata(ctx->teedev); + struct optee_context_data *ctxdata = ctx->data; + struct optee_session *sess; + int rc = -EINVAL; + + mutex_lock(&ctxdata->mutex); + + sess = find_session(ctxdata, session); + if (sess && (sess->use_sys_thread || + optee_cq_incr_sys_thread_count(&optee->call_queue))) { + sess->use_sys_thread = true; + rc = 0; + } + + mutex_unlock(&ctxdata->mutex); + + return rc; +} + int optee_close_session_helper(struct tee_context *ctx, u32 session, bool system_thread) { @@ -380,6 +483,9 @@ int optee_close_session_helper(struct tee_context *ctx, u32 session, optee_free_msg_arg(ctx, entry, offs); + if (system_thread) + optee_cq_decr_sys_thread_count(&optee->call_queue); + return 0; } diff --git a/drivers/tee/optee/ffa_abi.c b/drivers/tee/optee/ffa_abi.c index 5fde9d4100e38a..0c905569134351 100644 --- a/drivers/tee/optee/ffa_abi.c +++ b/drivers/tee/optee/ffa_abi.c @@ -852,8 +852,7 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev) if (rc) goto err_unreg_supp_teedev; mutex_init(&optee->ffa.mutex); - mutex_init(&optee->call_queue.mutex); - INIT_LIST_HEAD(&optee->call_queue.waiters); + optee_cq_init(&optee->call_queue, 0); optee_supp_init(&optee->supp); optee_shm_arg_cache_init(optee, arg_cache_flags); ffa_dev_set_drvdata(ffa_dev, optee); diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h index 2019ddb3829296..391c9ae5765244 100644 --- a/drivers/tee/optee/optee_private.h +++ b/drivers/tee/optee/optee_private.h @@ -40,15 +40,33 @@ typedef void (optee_invoke_fn)(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, struct arm_smccc_res *); +/* + * struct optee_call_waiter - TEE entry may need to wait for a free TEE thread + * @list_node Reference in waiters list + * @c Waiting completion reference + * @sys_thread_req True if waiter belongs to a system thread + */ struct optee_call_waiter { struct list_head list_node; struct completion c; + bool sys_thread; }; +/* + * struct optee_call_queue - OP-TEE call queue management + * @mutex Serializes access to this struct + * @waiters List of threads waiting to enter OP-TEE + * @total_thread_count Overall number of thread context in OP-TEE or 0 + * @free_thread_count Number of threads context free in OP-TEE + * @sys_thread_req_count Number of registered system thread sessions + */ struct optee_call_queue { /* Serializes access to this struct */ struct mutex mutex; struct list_head waiters; + int total_thread_count; + int free_thread_count; + int sys_thread_req_count; }; struct optee_notif { @@ -230,6 +248,7 @@ int optee_supp_send(struct tee_context *ctx, u32 ret, u32 num_params, int optee_open_session(struct tee_context *ctx, struct tee_ioctl_open_session_arg *arg, struct tee_param *param); +int optee_system_session(struct tee_context *ctx, u32 session); int optee_close_session_helper(struct tee_context *ctx, u32 session, bool system_thread); int optee_close_session(struct tee_context *ctx, u32 session); @@ -279,6 +298,7 @@ static inline void optee_to_msg_param_value(struct optee_msg_param *mp, mp->u.value.c = p->u.value.c; } +void optee_cq_init(struct optee_call_queue *cq, int thread_count); void optee_cq_wait_init(struct optee_call_queue *cq, struct optee_call_waiter *w, bool sys_thread); void optee_cq_wait_for_completion(struct optee_call_queue *cq, diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c index 0efd10483f1b74..75d5fc92594786 100644 --- a/drivers/tee/optee/smc_abi.c +++ b/drivers/tee/optee/smc_abi.c @@ -1092,6 +1092,7 @@ static const struct tee_driver_ops optee_clnt_ops = { .release = optee_release, .open_session = optee_open_session, .close_session = optee_close_session, + .system_session = optee_system_session, .invoke_func = optee_invoke_func, .cancel_req = optee_cancel_req, .shm_register = optee_shm_register, @@ -1223,6 +1224,16 @@ static bool optee_msg_exchange_capabilities(optee_invoke_fn *invoke_fn, return true; } +static unsigned int optee_msg_get_thread_count(optee_invoke_fn *invoke_fn) +{ + struct arm_smccc_res res; + + invoke_fn(OPTEE_SMC_GET_THREAD_COUNT, 0, 0, 0, 0, 0, 0, 0, &res); + if (res.a0) + return 0; + return res.a1; +} + static struct tee_shm_pool * optee_config_shm_memremap(optee_invoke_fn *invoke_fn, void **memremaped_shm) { @@ -1362,6 +1373,7 @@ static int optee_probe(struct platform_device *pdev) struct optee *optee = NULL; void *memremaped_shm = NULL; unsigned int rpc_param_count; + unsigned int thread_count; struct tee_device *teedev; struct tee_context *ctx; u32 max_notif_value; @@ -1385,6 +1397,7 @@ static int optee_probe(struct platform_device *pdev) return -EINVAL; } + thread_count = optee_msg_get_thread_count(invoke_fn); if (!optee_msg_exchange_capabilities(invoke_fn, &sec_caps, &max_notif_value, &rpc_param_count)) { @@ -1474,8 +1487,7 @@ static int optee_probe(struct platform_device *pdev) if (rc) goto err_unreg_supp_teedev; - mutex_init(&optee->call_queue.mutex); - INIT_LIST_HEAD(&optee->call_queue.waiters); + optee_cq_init(&optee->call_queue, thread_count); optee_supp_init(&optee->supp); optee->smc.memremaped_shm = memremaped_shm; optee->pool = pool;