text: /*
   * Copyright (c) 2013-2020, ARM Limited and Contributors. All rights reserved.
   *
   * SPDX-License-Identifier: BSD-3-Clause
   */
  
  #include <assert.h>
  #include <string.h>
  
  #include <arch.h>
  #include <arch_features.h>
  #include <arch_helpers.h>
  #include <bl31/bl31.h>
  #include <bl31/ehf.h>
  #include <common/bl_common.h>
  #include <common/debug.h>
  #include <common/runtime_svc.h>
  #include <drivers/console.h>
  #include <lib/el3_runtime/context_mgmt.h>
  #include <lib/pmf/pmf.h>
  #include <lib/runtime_instr.h>
  #include <plat/common/platform.h>
  #include <services/std_svc.h>
  
  #if ENABLE_RUNTIME_INSTRUMENTATION
  PMF_REGISTER_SERVICE_SMC(rt_instr_svc, PMF_RT_INSTR_SVC_ID,
  	RT_INSTR_TOTAL_IDS, PMF_STORE_ENABLE)
  #endif
  
  /*******************************************************************************
   * This function pointer is used to initialise the BL32 image. It's initialized
   * by SPD calling bl31_register_bl32_init after setting up all things necessary
   * for SP execution. In cases where both SPD and SP are absent, or when SPD
   * finds it impossible to execute SP, this pointer is left as NULL
   ******************************************************************************/
  static int32_t (*bl32_init)(void);
  
  /*******************************************************************************
   * Variable to indicate whether next image to execute after BL31 is BL33
   * (non-secure & default) or BL32 (secure).
   ******************************************************************************/
  static uint32_t next_image_type = NON_SECURE;
  
  #ifdef SUPPORT_UNKNOWN_MPID
  /*
   * Flag to know whether an unsupported MPID has been detected. To avoid having it
   * landing on the .bss section, it is initialized to a non-zero value, this way
   * we avoid potential WAW hazards during system bring up.
   * */
  volatile uint32_t unsupported_mpid_flag = 1;
  #endif
  
  /*
   * Implement the ARM Standard Service function to get arguments for a
   * particular service.
   */
  uintptr_t get_arm_std_svc_args(unsigned int svc_mask)
  {
  	/* Setup the arguments for PSCI Library */
  	DEFINE_STATIC_PSCI_LIB_ARGS_V1(psci_args, bl31_warm_entrypoint);
  
  	/* PSCI is the only ARM Standard Service implemented */
  	assert(svc_mask == PSCI_FID_MASK);
  
  	return (uintptr_t)&psci_args;
  }
  
  /*******************************************************************************
   * Simple function to initialise all BL31 helper libraries.
   ******************************************************************************/
  void __init bl31_lib_init(void)
  {
  	cm_init();
  }
  
  /*******************************************************************************
   * Setup function for BL31.
   ******************************************************************************/
  void bl31_setup(u_register_t arg0, u_register_t arg1, u_register_t arg2,
  		u_register_t arg3)
  {
  	/* Perform early platform-specific setup */
  	bl31_early_platform_setup2(arg0, arg1, arg2, arg3);
  
  	/* Perform late platform-specific setup */
  	bl31_plat_arch_setup();
  
  #if CTX_INCLUDE_PAUTH_REGS
  	/*
  	 * Assert that the ARMv8.3-PAuth registers are present or an access
  	 * fault will be triggered when they are being saved or restored.
  	 */
  	assert(is_armv8_3_pauth_present());
  #endif /* CTX_INCLUDE_PAUTH_REGS */
  }
  
  /*******************************************************************************
   * BL31 is responsible for setting up the runtime services for the primary cpu
   * before passing control to the bootloader or an Operating System. This
   * function calls runtime_svc_init() which initializes all registered runtime
   * services. The run time services would setup enough context for the core to
   * switch to the next exception level. When this function returns, the core will
   * switch to the programmed exception level via an ERET.
   ******************************************************************************/
  void bl31_main(void)
  {
  	NOTICE("BL31: %s\n", version_string);
  	NOTICE("BL31: %s\n", build_message);
  
  #ifdef SUPPORT_UNKNOWN_MPID
  	if (unsupported_mpid_flag == 0) {
  		NOTICE("Unsupported MPID detected!\n");
  	}
  #endif
  
  	/* Perform platform setup in BL31 */
  	bl31_platform_setup();
  
  	/* Initialise helper libraries */
  	bl31_lib_init();
  
  #if EL3_EXCEPTION_HANDLING
  	INFO("BL31: Initialising Exception Handling Framework\n");
  	ehf_init();
  #endif
  
  	/* Initialize the runtime services e.g. psci. */
  	INFO("BL31: Initializing runtime services\n");
  	runtime_svc_init();
  
  	/*
  	 * All the cold boot actions on the primary cpu are done. We now need to
  	 * decide which is the next image (BL32 or BL33) and how to execute it.
  	 * If the SPD runtime service is present, it would want to pass control
  	 * to BL32 first in S-EL1. In that case, SPD would have registered a
  	 * function to initialize bl32 where it takes responsibility of entering
  	 * S-EL1 and returning control back to bl31_main. Once this is done we
  	 * can prepare entry into BL33 as normal.
  	 */
  
  	/*
  	 * If SPD had registered an init hook, invoke it.
  	 */
  	if (bl32_init != NULL) {
  		INFO("BL31: Initializing BL32\n");
  
  		int32_t rc = (*bl32_init)();
  
  		if (rc == 0)
  			WARN("BL31: BL32 initialization failed\n");
  	}
  	/*
  	 * We are ready to enter the next EL. Prepare entry into the image
  	 * corresponding to the desired security state after the next ERET.
  	 */
  	bl31_prepare_next_image_entry();
  
  	console_flush();
  
  	/*
  	 * Perform any platform specific runtime setup prior to cold boot exit
  	 * from BL31
  	 */
  	bl31_plat_runtime_setup();
  }
  
  /*******************************************************************************
   * Accessor functions to help runtime services decide which image should be
   * executed after BL31. This is BL33 or the non-secure bootloader image by
   * default but the Secure payload dispatcher could override this by requesting
   * an entry into BL32 (Secure payload) first. If it does so then it should use
   * the same API to program an entry into BL33 once BL32 initialisation is
   * complete.
   ******************************************************************************/
  void bl31_set_next_image_type(uint32_t security_state)
  {
  	assert(sec_state_is_valid(security_state));
  	next_image_type = security_state;
  }
  
  uint32_t bl31_get_next_image_type(void)
  {
  	return next_image_type;
  }
  
  /*******************************************************************************
   * This function programs EL3 registers and performs other setup to enable entry
   * into the next image after BL31 at the next ERET.
   ******************************************************************************/
  void __init bl31_prepare_next_image_entry(void)
  {
  	entry_point_info_t *next_image_info;
  	uint32_t image_type;
  
  #if CTX_INCLUDE_AARCH32_REGS
  	/*
  	 * Ensure that the build flag to save AArch32 system registers in CPU
  	 * context is not set for AArch64-only platforms.
  	 */
  	if (el_implemented(1) == EL_IMPL_A64ONLY) {
  		ERROR("EL1 supports AArch64-only. Please set build flag "
  				"CTX_INCLUDE_AARCH32_REGS = 0\n");
  		panic();
  	}
  #endif
  
  	/* Determine which image to execute next */
  	image_type = bl31_get_next_image_type();
  
  	/* Program EL3 registers to enable entry into the next EL */
  	next_image_info = bl31_plat_get_next_image_ep_info(image_type);
  	assert(next_image_info != NULL);
  	assert(image_type == GET_SECURITY_STATE(next_image_info->h.attr));
  
  	INFO("BL31: Preparing for EL3 exit to %s world\n",
  		(image_type == SECURE) ? "secure" : "normal");
  	print_entry_point_info(next_image_info);
  	cm_init_my_context(next_image_info);
  	cm_prepare_el3_exit(image_type);
  }
  
  /*******************************************************************************
   * This function initializes the pointer to BL32 init function. This is expected
   * to be called by the SPD after it finishes all its initialization
   ******************************************************************************/
  void bl31_register_bl32_init(int32_t (*func)(void))
  {
  	bl32_init = func;
  }
  