Adds TEE system invocation context provisioning for a Linux driver to provision execution contexts for invocation of system service hosted in TEE. OP-TEE SMC ABI implements such invocation context provisioning.

This feature is needed when a TEE invocation cannot afford to wait for a free TEE thread when all TEE threads context are used and suspended as these may be suspended waiting for a system service, as an SCMI clock or voltage regulator, to be enabled. An example is when OP-TEE invokes a Linux OS remote service (RPC) to access an eMMC RPMB partition and the eMMC device is supplied by an OP-TEE SCMI regulator.

Signed-off-by: Etienne Carriere etienne.carriere@linaro.org --- Changes since v3: - Fixed new SMC funcIDs to reserved/unreserve OP-TEE thread contexts: minor renaming + define as fastcall funcIDs. - Moved system_ctx_count from generic struct tee_context to optee's private struct optee_context_data. This changes optee smc_abi.c to release reserved thread contexts when the optee device is released. - Fixed inline description comments.

No change since v2

Change since v1 - Addressed comment on Linux client to claim reservation on TEE context. This brings 2 new operations from client to TEE to request and release system thread contexts: 2 new tee_drv.h API functions, 2 new ops functions in struct tee_driver_ops. The OP-TEE implement shall implement 2 new fastcall SMC funcIDs. - Fixed typos in commit message. --- drivers/tee/optee/optee_private.h | 9 ++++- drivers/tee/optee/optee_smc.h | 60 +++++++++++++++++++++++++++-- drivers/tee/optee/smc_abi.c | 64 ++++++++++++++++++++++++++++++- drivers/tee/tee_core.c | 18 +++++++++ include/linux/tee_drv.h | 18 +++++++++ 5 files changed, 163 insertions(+), 6 deletions(-)

diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h index 04ae58892608..b409ed2acfa6 100644 --- a/drivers/tee/optee/optee_private.h +++ b/drivers/tee/optee/optee_private.h @@ -182,10 +182,17 @@ struct optee_session { u32 session_id; };

+/* + * struct optee_context_data - TEE context private data + * @mutex Serializes access to this struct + * @sess_list List of TEE sessions opened for this context + * @system_ctx_count Number of system invocation contexts provisioned in TEE + * for this context + */ struct optee_context_data { - /* Serializes access to this struct */ struct mutex mutex; struct list_head sess_list; + size_t system_ctx_count; };

struct optee_rpc_param { diff --git a/drivers/tee/optee/optee_smc.h b/drivers/tee/optee/optee_smc.h index 73b5e7760d10..7d08ccaf47d4 100644 --- a/drivers/tee/optee/optee_smc.h +++ b/drivers/tee/optee/optee_smc.h @@ -108,7 +108,8 @@ struct optee_smc_call_get_os_revision_result { * Call with struct optee_msg_arg as argument * * When called with OPTEE_SMC_CALL_WITH_RPC_ARG or - * OPTEE_SMC_CALL_WITH_REGD_ARG in a0 there is one RPC struct optee_msg_arg + * OPTEE_SMC_CALL_WITH_REGD_ARG or OPTEE_SMC_FUNCID_CALL_SYSTEM_WITH_REGD_ARG + * in a0 there is one RPC struct optee_msg_arg * following after the first struct optee_msg_arg. The RPC struct * optee_msg_arg has reserved space for the number of RPC parameters as * returned by OPTEE_SMC_EXCHANGE_CAPABILITIES. @@ -130,8 +131,8 @@ struct optee_smc_call_get_os_revision_result { * a4-6 Not used * a7 Hypervisor Client ID register * - * Call register usage, OPTEE_SMC_CALL_WITH_REGD_ARG: - * a0 SMC Function ID, OPTEE_SMC_CALL_WITH_REGD_ARG + * Call register usage, OPTEE_SMC_CALL_WITH_REGD_ARG and OPTEE_SMC_FUNCID_CALL_SYSTEM_WITH_REGD_ARG: + * a0 SMC Function ID, OPTEE_SMC_CALL_WITH_REGD_ARG or OPTEE_SMC_FUNCID_CALL_SYSTEM_WITH_REGD_ARG * a1 Upper 32 bits of a 64-bit shared memory cookie * a2 Lower 32 bits of a 64-bit shared memory cookie * a3 Offset of the struct optee_msg_arg in the shared memory with the @@ -175,6 +176,8 @@ struct optee_smc_call_get_os_revision_result { OPTEE_SMC_STD_CALL_VAL(OPTEE_SMC_FUNCID_CALL_WITH_RPC_ARG) #define OPTEE_SMC_CALL_WITH_REGD_ARG \ OPTEE_SMC_STD_CALL_VAL(OPTEE_SMC_FUNCID_CALL_WITH_REGD_ARG) +#define OPTEE_SMC_CALL_SYSTEM_WITH_REGD_ARG \ + OPTEE_SMC_STD_CALL_VAL(OPTEE_SMC_FUNCID_CALL_SYSTEM_WITH_REGD_ARG)

/* * Get Shared Memory Config @@ -254,6 +257,8 @@ struct optee_smc_get_shm_config_result { #define OPTEE_SMC_SEC_CAP_ASYNC_NOTIF BIT(5) /* Secure world supports pre-allocating RPC arg struct */ #define OPTEE_SMC_SEC_CAP_RPC_ARG BIT(6) +/* Secure world provisions thread for system service invocation */ +#define OPTEE_SMC_SEC_CAP_SYSTEM_THREAD BIT(7)

#define OPTEE_SMC_FUNCID_EXCHANGE_CAPABILITIES 9 #define OPTEE_SMC_EXCHANGE_CAPABILITIES \ @@ -426,6 +431,55 @@ struct optee_smc_disable_shm_cache_result { /* See OPTEE_SMC_CALL_WITH_REGD_ARG above */ #define OPTEE_SMC_FUNCID_CALL_WITH_REGD_ARG 19

+/* See OPTEE_SMC_CALL_SYSTEM_WITH_REGD_ARG above */ +#define OPTEE_SMC_FUNCID_CALL_SYSTEM_WITH_REGD_ARG 20 + +/* + * Request reservation of a system invocation thread context in OP-TEE + * + * Call register usage: + * a0 SMC Function ID: OPTEE_SMC_RESERVE_SYS_THREAD + * a1-6 Not used + * a7 Hypervisor Client ID register + * + * Normal return register usage: + * a0 Return value, OPTEE_SMC_RETURN_* + * a1-3 Not used + * a4-7 Preserved + * + * Possible return values: + * OPTEE_SMC_RETURN_UNKNOWN_FUNCTION Trusted OS does not recognize this + * function. + * OPTEE_SMC_RETURN_OK Call successfully completed. + * OPTEE_SMC_RETURN_ETHREAD_LIMIT Number of Trusted OS threads exceeded + * for the request. + */ +#define OPTEE_SMC_FUNCID_RESERVE_SYS_THREAD 21 +#define OPTEE_SMC_RESERVE_SYS_THREAD \ + OPTEE_SMC_FAST_CALL_VAL(OPTEE_SMC_FUNCID_RESERVE_SYS_THREAD) + +/* + * Unregister reservation of a system invocation thread context in OP-TEE + * + * Call register usage: + * a0 SMC Function ID: OPTEE_SMC_UNRESERVE_SYS_THREAD + * a1-6 Not used + * a7 Hypervisor Client ID register + * + * Normal return register usage: + * a0 Return value, OPTEE_SMC_RETURN_* + * a1-3 Not used + * a4-7 Preserved + * + * Possible return values: + * OPTEE_SMC_RETURN_UNKNOWN_FUNCTION Trusted OS does not recognize this + * function. + * OPTEE_SMC_RETURN_OK Call successfully completed. + */ +#define OPTEE_SMC_FUNCID_UNRESERVE_SYS_THREAD 22 +#define OPTEE_SMC_UNRESERVE_SYS_THREAD \ + OPTEE_SMC_FAST_CALL_VAL(OPTEE_SMC_FUNCID_UNRESERVE_SYS_THREAD) + /* * Resume from RPC (for example after processing a foreign interrupt) * diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c index a1c1fa1a9c28..8668ab5f1c8b 100644 --- a/drivers/tee/optee/smc_abi.c +++ b/drivers/tee/optee/smc_abi.c @@ -867,6 +867,7 @@ static void optee_handle_rpc(struct tee_context *ctx, static int optee_smc_do_call_with_arg(struct tee_context *ctx, struct tee_shm *shm, u_int offs) { + struct optee_context_data *ctxdata = ctx->data; struct optee *optee = tee_get_drvdata(ctx->teedev); struct optee_call_waiter w; struct optee_rpc_param param = { }; @@ -889,7 +890,10 @@ static int optee_smc_do_call_with_arg(struct tee_context *ctx, }

if (rpc_arg && tee_shm_is_dynamic(shm)) { - param.a0 = OPTEE_SMC_CALL_WITH_REGD_ARG; + if (ctxdata->system_ctx_count) + param.a0 = OPTEE_SMC_CALL_SYSTEM_WITH_REGD_ARG; + else + param.a0 = OPTEE_SMC_CALL_WITH_REGD_ARG; reg_pair_from_64(&param.a1, &param.a2, (u_long)shm); param.a3 = offs; } else { @@ -1077,6 +1081,50 @@ static void optee_get_version(struct tee_device *teedev, *vers = v; }

+static int optee_request_sys_ctx(struct tee_context *ctx) +{ + struct optee_context_data *ctxdata = ctx->data; + struct optee *optee = tee_get_drvdata(ctx->teedev); + struct arm_smccc_res res; + + if (!(optee->smc.sec_caps & OPTEE_SMC_SEC_CAP_SYSTEM_THREAD)) + return -EINVAL; + + optee->smc.invoke_fn(OPTEE_SMC_RESERVE_SYS_THREAD, + 0, 0, 0, 0, 0, 0, 0, &res); + + if (res.a0 != OPTEE_SMC_RETURN_OK) + return -EINVAL; + + mutex_lock(&ctxdata->mutex); + ctxdata->system_ctx_count++; + mutex_unlock(&ctxdata->mutex); + + return 0; +} + +static void optee_release_sys_ctx(struct tee_context *ctx) +{ + struct optee_context_data *ctxdata = ctx->data; + struct optee *optee = tee_get_drvdata(ctx->teedev); + struct arm_smccc_res res; + + if (!ctxdata->system_ctx_count) + return; + + optee->smc.invoke_fn(OPTEE_SMC_UNRESERVE_SYS_THREAD, + 0, 0, 0, 0, 0, 0, 0, &res); + + if (res.a0 != OPTEE_SMC_RETURN_OK) { + WARN_ONCE(1, "OP-TEE: Couldn't release reserved context\n"); + return; + } + + mutex_lock(&ctxdata->mutex); + ctxdata->system_ctx_count--; + mutex_unlock(&ctxdata->mutex); +} + static int optee_smc_open(struct tee_context *ctx) { struct optee *optee = tee_get_drvdata(ctx->teedev); @@ -1085,16 +1133,28 @@ static int optee_smc_open(struct tee_context *ctx) return optee_open(ctx, sec_caps & OPTEE_SMC_SEC_CAP_MEMREF_NULL); }

+static void optee_smc_release(struct tee_context *ctx) +{ + struct optee_context_data *ctxdata = ctx->data; + + while (ctxdata->system_ctx_count) + optee_release_sys_ctx(ctx); + + optee_release(ctx); +} + static const struct tee_driver_ops optee_clnt_ops = { .get_version = optee_get_version, .open = optee_smc_open, - .release = optee_release, + .release = optee_smc_release, .open_session = optee_open_session, .close_session = optee_close_session, .invoke_func = optee_invoke_func, .cancel_req = optee_cancel_req, .shm_register = optee_shm_register, .shm_unregister = optee_shm_unregister, + .system_ctx_request = optee_request_sys_ctx, + .system_ctx_release = optee_release_sys_ctx, };

static const struct tee_desc optee_clnt_desc = { diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index 98da206cd761..d6593c57f32d 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -5,6 +5,7 @@

#define pr_fmt(fmt) "%s: " fmt, __func__

+#include <linux/bug.h> #include <linux/cdev.h> #include <linux/cred.h> #include <linux/fs.h> @@ -1145,6 +1146,23 @@ void tee_client_close_context(struct tee_context *ctx) } EXPORT_SYMBOL_GPL(tee_client_close_context);

+int tee_client_request_system_context(struct tee_context *ctx) +{ + if (!ctx->teedev->desc->ops->system_ctx_request || + !ctx->teedev->desc->ops->system_ctx_release) + return -EINVAL; + + return ctx->teedev->desc->ops->system_ctx_request(ctx); +} +EXPORT_SYMBOL_GPL(tee_client_request_system_context); + +void tee_client_release_system_context(struct tee_context *ctx) +{ + if (ctx->teedev->desc->ops->system_ctx_release) + ctx->teedev->desc->ops->system_ctx_release(ctx); +} +EXPORT_SYMBOL_GPL(tee_client_release_system_context); + void tee_client_get_version(struct tee_context *ctx, struct tee_ioctl_version_data *vers) { diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h index 17eb1c5205d3..99d016eb7353 100644 --- a/include/linux/tee_drv.h +++ b/include/linux/tee_drv.h @@ -90,6 +90,8 @@ struct tee_param { * @supp_send: called for supplicant to send a response * @shm_register: register shared memory buffer in TEE * @shm_unregister: unregister shared memory buffer in TEE + * @system_ctx_request: Request provisioning of a new system context in TEE + * @system_ctx_release: Release a provisioned system context in TEE */ struct tee_driver_ops { void (*get_version)(struct tee_device *teedev, @@ -112,6 +114,8 @@ struct tee_driver_ops { struct page **pages, size_t num_pages, unsigned long start); int (*shm_unregister)(struct tee_context *ctx, struct tee_shm *shm); + int (*system_ctx_request)(struct tee_context *ctx); + void (*system_ctx_release)(struct tee_context *ctx); };

/** @@ -397,6 +401,20 @@ tee_client_open_context(struct tee_context *start, */ void tee_client_close_context(struct tee_context *ctx);

+/** + * tee_client_request_system_context() - Request reservation of a system context + * @ctx: TEE context reference + * + * @return 0 on success else an error code + */ +int tee_client_request_system_context(struct tee_context *ctx); + +/** + * tee_client_release_system_context() - Release a reserved system context + * @ctx: TEE context reference + */ +void tee_client_release_system_context(struct tee_context *ctx); + /** * tee_client_get_version() - Query version of TEE * @ctx: TEE context to TEE to query