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說明: 在默認的情況下，本文講述的是armv8 aarch64體系，optee 3.12.0代碼

文章目錄

• • • • 1、optee的fast call調(diào)用的代碼導(dǎo)讀

1、optee的fast call調(diào)用的代碼導(dǎo)讀

如果調(diào)用的是fast call，在ATF的代碼中，將會把optee_vector_table->fast_smc_entry地址賦給ELR_EL3寄存器，el3_exit退出后，PC將會跳轉(zhuǎn)到該地址處，對應(yīng)著optee_os中的線程向量表vector_fast_smc_entry地址

static uintptr_t opteed_smc_handler(uint32_t smc_fid,u_register_t x1,u_register_t x2,u_register_t x3,u_register_t x4,void *cookie,void *handle,u_register_t flags) { ...if (GET_SMC_TYPE(smc_fid) == SMC_TYPE_FAST) {cm_set_elr_el3(SECURE, (uint64_t)&optee_vector_table->fast_smc_entry);} else {cm_set_elr_el3(SECURE, (uint64_t)&optee_vector_table->yield_smc_entry);} ... }

optee_os中的線程向量表的定義

/** Vector table supplied to ARM Trusted Firmware (ARM-TF) at* initialization.** Note that ARM-TF depends on the layout of this vector table, any change* in layout has to be synced with ARM-TF.*/ FUNC thread_vector_table , : , .identity_mapb vector_std_smc_entryb vector_fast_smc_entryb vector_cpu_on_entryb vector_cpu_off_entryb vector_cpu_resume_entryb vector_cpu_suspend_entryb vector_fiq_entryb vector_system_off_entryb vector_system_reset_entry END_FUNC thread_vector_table DECLARE_KEEP_PAGER thread_vector_table

vector_fast_smc_entry的實現(xiàn)

LOCAL_FUNC vector_fast_smc_entry , : , .identity_mapreadjust_pcsub sp, sp, #THREAD_SMC_ARGS_SIZEstore_xregs sp, THREAD_SMC_ARGS_X0, 0, 7mov x0, spbl thread_handle_fast_smcload_xregs sp, THREAD_SMC_ARGS_X0, 1, 8add sp, sp, #THREAD_SMC_ARGS_SIZEldr x0, =TEESMC_OPTEED_RETURN_CALL_DONEsmc #0b . /* SMC should not return */ END_FUNC vector_fast_smc_entry

optee_os中fast call的實現(xiàn)

void thread_handle_fast_smc(struct thread_smc_args *args) {thread_check_canaries();#ifdef CFG_VIRTUALIZATIONif (!virt_set_guest(args->a7)) {args->a0 = OPTEE_SMC_RETURN_ENOTAVAIL;goto out;} #endiftee_entry_fast(args);#ifdef CFG_VIRTUALIZATIONvirt_unset_guest(); #endif/* Fast handlers must not unmask any exceptions */ out:__maybe_unused;assert(thread_get_exceptions() == THREAD_EXCP_ALL); } /* Note: this function is weak to let platforms add special handling */ void __weak tee_entry_fast(struct thread_smc_args *args) {__tee_entry_fast(args); } /** If tee_entry_fast() is overridden, it's still supposed to call this* function.*/ void __tee_entry_fast(struct thread_smc_args *args) {switch (args->a0) {/* Generic functions */case OPTEE_SMC_CALLS_COUNT:tee_entry_get_api_call_count(args);break;case OPTEE_SMC_CALLS_UID:tee_entry_get_api_uuid(args);break;case OPTEE_SMC_CALLS_REVISION:tee_entry_get_api_revision(args);break;case OPTEE_SMC_CALL_GET_OS_UUID:tee_entry_get_os_uuid(args);break;case OPTEE_SMC_CALL_GET_OS_REVISION:tee_entry_get_os_revision(args);break;/* OP-TEE specific SMC functions */ #ifdef CFG_CORE_RESERVED_SHMcase OPTEE_SMC_GET_SHM_CONFIG:tee_entry_get_shm_config(args);break; #endifcase OPTEE_SMC_L2CC_MUTEX:tee_entry_fastcall_l2cc_mutex(args);break;case OPTEE_SMC_EXCHANGE_CAPABILITIES:tee_entry_exchange_capabilities(args);break;case OPTEE_SMC_DISABLE_SHM_CACHE:tee_entry_disable_shm_cache(args);break;case OPTEE_SMC_ENABLE_SHM_CACHE:tee_entry_enable_shm_cache(args);break;case OPTEE_SMC_BOOT_SECONDARY:tee_entry_boot_secondary(args);break;case OPTEE_SMC_GET_THREAD_COUNT:tee_entry_get_thread_count(args);break;#if defined(CFG_VIRTUALIZATION)case OPTEE_SMC_VM_CREATED:tee_entry_vm_created(args);break;case OPTEE_SMC_VM_DESTROYED:tee_entry_vm_destroyed(args);break; #endifdefault:args->a0 = OPTEE_SMC_RETURN_UNKNOWN_FUNCTION;break;} }

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