services/spd/trusty/trusty.c - imx-atf - Git at Google

 /*
  * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */

 #include <arch_helpers.h>
 #include <assert.h> /* for context_mgmt.h */
 #include <bl31.h>
 #include <bl_common.h>
 #include <context_mgmt.h>
 #include <debug.h>
 #include <interrupt_mgmt.h>
 #include <platform.h>
 #include <runtime_svc.h>
 #include <stdbool.h>
 #include <string.h>

 #include "sm_err.h"
 #include "smcall.h"

 /* macro to check if Hypervisor is enabled in the HCR_EL2 register */
 #define HYP_ENABLE_FLAG		0x286001

 struct trusty_stack {
 	uint8_t space[PLATFORM_STACK_SIZE] __aligned(16);
 	uint32_t end;
 };

 struct trusty_cpu_ctx {
 	cpu_context_t	cpu_ctx;
 	void		*saved_sp;
 	uint32_t	saved_security_state;
 	int		fiq_handler_active;
 	uint64_t	fiq_handler_pc;
 	uint64_t	fiq_handler_cpsr;
 	uint64_t	fiq_handler_sp;
 	uint64_t	fiq_pc;
 	uint64_t	fiq_cpsr;
 	uint64_t	fiq_sp_el1;
 	gp_regs_t	fiq_gpregs;
 	struct trusty_stack	secure_stack;
 };

 struct args {
 	uint64_t	r0;
 	uint64_t	r1;
 	uint64_t	r2;
 	uint64_t	r3;
 	uint64_t	r4;
 	uint64_t	r5;
 	uint64_t	r6;
 	uint64_t	r7;
 };

 static struct trusty_cpu_ctx trusty_cpu_ctx[PLATFORM_CORE_COUNT];

 struct args trusty_init_context_stack(void **sp, void *new_stack);
 struct args trusty_context_switch_helper(void **sp, void *smc_params);

 static uint32_t current_vmid;

 static struct trusty_cpu_ctx *get_trusty_ctx(void)
 {
 	return &trusty_cpu_ctx[plat_my_core_pos()];
 }

 static uint32_t is_hypervisor_mode(void)
 {
 	uint64_t hcr = read_hcr();

 	return !!(hcr & HYP_ENABLE_FLAG);
 }

 static struct args trusty_context_switch(uint32_t security_state, uint64_t r0,
 					 uint64_t r1, uint64_t r2, uint64_t r3)
 {
 	struct args ret;
 	struct trusty_cpu_ctx *ctx = get_trusty_ctx();
 	struct trusty_cpu_ctx *ctx_smc;

 	assert(ctx->saved_security_state != security_state);

 	ret.r7 = 0;
 	if (is_hypervisor_mode()) {
 		/* According to the ARM DEN0028A spec, VMID is stored in x7 */
 		ctx_smc = cm_get_context(NON_SECURE);
 		assert(ctx_smc);
 		ret.r7 = SMC_GET_GP(ctx_smc, CTX_GPREG_X7);
 	}
 	/* r4, r5, r6 reserved for future use. */
 	ret.r6 = 0;
 	ret.r5 = 0;
 	ret.r4 = 0;
 	ret.r3 = r3;
 	ret.r2 = r2;
 	ret.r1 = r1;
 	ret.r0 = r0;

 	/*
 	 * To avoid the additional overhead in PSCI flow, skip FP context
 	 * saving/restoring in case of CPU suspend and resume, asssuming that
 	 * when it's needed the PSCI caller has preserved FP context before
 	 * going here.
 	 */
 	if (r0 != SMC_FC_CPU_SUSPEND && r0 != SMC_FC_CPU_RESUME)
 		fpregs_context_save(get_fpregs_ctx(cm_get_context(security_state)));
 	cm_el1_sysregs_context_save(security_state);

 	ctx->saved_security_state = security_state;
 	ret = trusty_context_switch_helper(&ctx->saved_sp, &ret);

 	assert(ctx->saved_security_state == !security_state);

 	cm_el1_sysregs_context_restore(security_state);
 	if (r0 != SMC_FC_CPU_SUSPEND && r0 != SMC_FC_CPU_RESUME)
 		fpregs_context_restore(get_fpregs_ctx(cm_get_context(security_state)));

 	cm_set_next_eret_context(security_state);

 	return ret;
 }

 static uint64_t trusty_fiq_handler(uint32_t id,
 				   uint32_t flags,
 				   void *handle,
 				   void *cookie)
 {
 	struct args ret;
 	struct trusty_cpu_ctx *ctx = get_trusty_ctx();

 	assert(!is_caller_secure(flags));

 	ret = trusty_context_switch(NON_SECURE, SMC_FC_FIQ_ENTER, 0, 0, 0);
 	if (ret.r0) {
 		SMC_RET0(handle);
 	}

 	if (ctx->fiq_handler_active) {
 		INFO("%s: fiq handler already active\n", __func__);
 		SMC_RET0(handle);
 	}

 	ctx->fiq_handler_active = 1;
 	memcpy(&ctx->fiq_gpregs, get_gpregs_ctx(handle), sizeof(ctx->fiq_gpregs));
 	ctx->fiq_pc = SMC_GET_EL3(handle, CTX_ELR_EL3);
 	ctx->fiq_cpsr = SMC_GET_EL3(handle, CTX_SPSR_EL3);
 	ctx->fiq_sp_el1 = read_ctx_reg(get_sysregs_ctx(handle), CTX_SP_EL1);

 	write_ctx_reg(get_sysregs_ctx(handle), CTX_SP_EL1, ctx->fiq_handler_sp);
 	cm_set_elr_spsr_el3(NON_SECURE, ctx->fiq_handler_pc, ctx->fiq_handler_cpsr);

 	SMC_RET0(handle);
 }

 static uint64_t trusty_set_fiq_handler(void *handle, uint64_t cpu,
 			uint64_t handler, uint64_t stack)
 {
 	struct trusty_cpu_ctx *ctx;

 	if (cpu >= PLATFORM_CORE_COUNT) {
 		ERROR("%s: cpu %lld >= %d\n", __func__, cpu, PLATFORM_CORE_COUNT);
 		return SM_ERR_INVALID_PARAMETERS;
 	}

 	ctx = &trusty_cpu_ctx[cpu];
 	ctx->fiq_handler_pc = handler;
 	ctx->fiq_handler_cpsr = SMC_GET_EL3(handle, CTX_SPSR_EL3);
 	ctx->fiq_handler_sp = stack;

 	SMC_RET1(handle, 0);
 }

 static uint64_t trusty_get_fiq_regs(void *handle)
 {
 	struct trusty_cpu_ctx *ctx = get_trusty_ctx();
 	uint64_t sp_el0 = read_ctx_reg(&ctx->fiq_gpregs, CTX_GPREG_SP_EL0);

 	SMC_RET4(handle, ctx->fiq_pc, ctx->fiq_cpsr, sp_el0, ctx->fiq_sp_el1);
 }

 static uint64_t trusty_fiq_exit(void *handle, uint64_t x1, uint64_t x2, uint64_t x3)
 {
 	struct args ret;
 	struct trusty_cpu_ctx *ctx = get_trusty_ctx();

 	if (!ctx->fiq_handler_active) {
 		NOTICE("%s: fiq handler not active\n", __func__);
 		SMC_RET1(handle, SM_ERR_INVALID_PARAMETERS);
 	}

 	ret = trusty_context_switch(NON_SECURE, SMC_FC_FIQ_EXIT, 0, 0, 0);
 	if (ret.r0 != 1) {
 		INFO("%s(%p) SMC_FC_FIQ_EXIT returned unexpected value, %lld\n",
 		       __func__, handle, ret.r0);
 	}

 	/*
 	 * Restore register state to state recorded on fiq entry.
 	 *
 	 * x0, sp_el1, pc and cpsr need to be restored because el1 cannot
 	 * restore them.
 	 *
 	 * x1-x4 and x8-x17 need to be restored here because smc_handler64
 	 * corrupts them (el1 code also restored them).
 	 */
 	memcpy(get_gpregs_ctx(handle), &ctx->fiq_gpregs, sizeof(ctx->fiq_gpregs));
 	ctx->fiq_handler_active = 0;
 	write_ctx_reg(get_sysregs_ctx(handle), CTX_SP_EL1, ctx->fiq_sp_el1);
 	cm_set_elr_spsr_el3(NON_SECURE, ctx->fiq_pc, ctx->fiq_cpsr);

 	SMC_RET0(handle);
 }

 static uintptr_t trusty_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)
 {
 	struct args ret;
 	uint32_t vmid = 0;
 	entry_point_info_t *ep_info = bl31_plat_get_next_image_ep_info(SECURE);

 	/*
 	 * Return success for SET_ROT_PARAMS if Trusty is not present, as
 	 * Verified Boot is not even supported and returning success here
 	 * would not compromise the boot process.
 	 */
 	if (!ep_info && (smc_fid == SMC_YC_SET_ROT_PARAMS)) {
 		SMC_RET1(handle, 0);
 	} else if (!ep_info) {
 		SMC_RET1(handle, SMC_UNK);
 	}

 	if (is_caller_secure(flags)) {
 		if (smc_fid == SMC_YC_NS_RETURN) {
 			ret = trusty_context_switch(SECURE, x1, 0, 0, 0);
 			SMC_RET8(handle, ret.r0, ret.r1, ret.r2, ret.r3,
 				 ret.r4, ret.r5, ret.r6, ret.r7);
 		}
 		INFO("%s (0x%x, 0x%lx, 0x%lx, 0x%lx, 0x%lx, %p, %p, 0x%lx) \
 		     cpu %d, unknown smc\n",
 		     __func__, smc_fid, x1, x2, x3, x4, cookie, handle, flags,
 		     plat_my_core_pos());
 		SMC_RET1(handle, SMC_UNK);
 	} else {
 		switch (smc_fid) {
 		case SMC_FC64_SET_FIQ_HANDLER:
 			return trusty_set_fiq_handler(handle, x1, x2, x3);
 		case SMC_FC64_GET_FIQ_REGS:
 			return trusty_get_fiq_regs(handle);
 		case SMC_FC_FIQ_EXIT:
 			return trusty_fiq_exit(handle, x1, x2, x3);
 		default:
 			if (is_hypervisor_mode())
 				vmid = SMC_GET_GP(handle, CTX_GPREG_X7);

 			if ((current_vmid != 0) && (current_vmid != vmid)) {
 				/* This message will cause SMC mechanism
 				 * abnormal in multi-guest environment.
 				 * Change it to WARN in case you need it.
 				 */
 				VERBOSE("Previous SMC not finished.\n");
 				SMC_RET1(handle, SM_ERR_BUSY);
 			}
 			current_vmid = vmid;
 			ret = trusty_context_switch(NON_SECURE, smc_fid, x1,
 				x2, x3);
 			current_vmid = 0;
 			SMC_RET1(handle, ret.r0);
 		}
 	}
 }

 static int32_t trusty_init(void)
 {
 	void el3_exit(void);
 	entry_point_info_t *ep_info;
 	struct args zero_args = {0};
 	struct trusty_cpu_ctx *ctx = get_trusty_ctx();
 	uint32_t cpu = plat_my_core_pos();
 	int reg_width = GET_RW(read_ctx_reg(get_el3state_ctx(&ctx->cpu_ctx),
 			       CTX_SPSR_EL3));

 	/*
 	 * Get information about the Trusty image. Its absence is a critical
 	 * failure.
 	 */
 	ep_info = bl31_plat_get_next_image_ep_info(SECURE);
 	assert(ep_info);

 	fpregs_context_save(get_fpregs_ctx(cm_get_context(NON_SECURE)));
 	cm_el1_sysregs_context_save(NON_SECURE);

 	cm_set_context(&ctx->cpu_ctx, SECURE);
 	cm_init_my_context(ep_info);

 	/*
 	 * Adjust secondary cpu entry point for 32 bit images to the
 	 * end of exeption vectors
 	 */
 	if ((cpu != 0) && (reg_width == MODE_RW_32)) {
 		INFO("trusty: cpu %d, adjust entry point to 0x%lx\n",
 		     cpu, ep_info->pc + (1U << 5));
 		cm_set_elr_el3(SECURE, ep_info->pc + (1U << 5));
 	}

 	cm_el1_sysregs_context_restore(SECURE);
 	fpregs_context_restore(get_fpregs_ctx(cm_get_context(SECURE)));
 	cm_set_next_eret_context(SECURE);

 	ctx->saved_security_state = ~0; /* initial saved state is invalid */
 	trusty_init_context_stack(&ctx->saved_sp, &ctx->secure_stack.end);

 	trusty_context_switch_helper(&ctx->saved_sp, &zero_args);

 	cm_el1_sysregs_context_restore(NON_SECURE);
 	fpregs_context_restore(get_fpregs_ctx(cm_get_context(NON_SECURE)));
 	cm_set_next_eret_context(NON_SECURE);

 	return 1;
 }

 static void trusty_cpu_suspend(uint32_t off)
 {
 	struct args ret;

 	ret = trusty_context_switch(NON_SECURE, SMC_FC_CPU_SUSPEND, off, 0, 0);
 	if (ret.r0 != 0) {
 		INFO("%s: cpu %d, SMC_FC_CPU_SUSPEND returned unexpected value, %lld\n",
 		     __func__, plat_my_core_pos(), ret.r0);
 	}
 }

 static void trusty_cpu_resume(uint32_t on)
 {
 	struct args ret;

 	ret = trusty_context_switch(NON_SECURE, SMC_FC_CPU_RESUME, on, 0, 0);
 	if (ret.r0 != 0) {
 		INFO("%s: cpu %d, SMC_FC_CPU_RESUME returned unexpected value, %lld\n",
 		     __func__, plat_my_core_pos(), ret.r0);
 	}
 }

 static int32_t trusty_cpu_off_handler(u_register_t unused)
 {
 	trusty_cpu_suspend(1);

 	return 0;
 }

 static void trusty_cpu_on_finish_handler(u_register_t unused)
 {
 	struct trusty_cpu_ctx *ctx = get_trusty_ctx();

 	if (!ctx->saved_sp) {
 		trusty_init();
 	} else {
 		trusty_cpu_resume(1);
 	}
 }

 static void trusty_cpu_suspend_handler(u_register_t unused)
 {
 	trusty_cpu_suspend(0);
 }

 static void trusty_cpu_suspend_finish_handler(u_register_t unused)
 {
 	trusty_cpu_resume(0);
 }

 static const spd_pm_ops_t trusty_pm = {
 	.svc_off = trusty_cpu_off_handler,
 	.svc_suspend = trusty_cpu_suspend_handler,
 	.svc_on_finish = trusty_cpu_on_finish_handler,
 	.svc_suspend_finish = trusty_cpu_suspend_finish_handler,
 };

 void plat_trusty_set_boot_args(aapcs64_params_t *args);

 #ifdef TSP_SEC_MEM_SIZE
 #pragma weak plat_trusty_set_boot_args
 void plat_trusty_set_boot_args(aapcs64_params_t *args)
 {
 	args->arg0 = TSP_SEC_MEM_SIZE;
 }
 #endif

 static int32_t trusty_setup(void)
 {
 	entry_point_info_t *ep_info;
 	uint32_t instr;
 	uint32_t flags;
 	int ret;
 	bool aarch32 = false;

 	/* Get trusty's entry point info */
 	ep_info = bl31_plat_get_next_image_ep_info(SECURE);
 	if (!ep_info) {
 		INFO("Trusty image missing.\n");
 		return -1;
 	}

 	instr = *(uint32_t *)ep_info->pc;

 	if (instr >> 24 == 0xeaU) {
 		INFO("trusty: Found 32 bit image\n");
 		aarch32 = true;
 	} else if (instr >> 8 == 0xd53810U || instr >> 16 == 0x9400U) {
 		INFO("trusty: Found 64 bit image\n");
 	} else {
 		NOTICE("trusty: Found unknown image, 0x%x\n", instr);
 	}

 	SET_PARAM_HEAD(ep_info, PARAM_EP, VERSION_1, SECURE | EP_ST_ENABLE);
 	if (!aarch32)
 		ep_info->spsr = SPSR_64(MODE_EL1, MODE_SP_ELX,
 					DISABLE_ALL_EXCEPTIONS);
 	else
 		ep_info->spsr = SPSR_MODE32(MODE32_svc, SPSR_T_ARM,
 					    SPSR_E_LITTLE,
 					    DAIF_FIQ_BIT |
 					    DAIF_IRQ_BIT |
 					    DAIF_ABT_BIT);
 	(void)memset(&ep_info->args, 0, sizeof(ep_info->args));
 	plat_trusty_set_boot_args(&ep_info->args);

 	/* register init handler */
 	bl31_register_bl32_init(trusty_init);

 	/* register power management hooks */
 	psci_register_spd_pm_hook(&trusty_pm);

 	/* register interrupt handler */
 	flags = 0;
 	set_interrupt_rm_flag(flags, NON_SECURE);
 	ret = register_interrupt_type_handler(INTR_TYPE_S_EL1,
 					      trusty_fiq_handler,
 					      flags);
 	if (ret)
 		ERROR("trusty: failed to register fiq handler, ret = %d\n", ret);

 	if (aarch32) {
 		entry_point_info_t *ns_ep_info;
 		uint32_t spsr;

 		ns_ep_info = bl31_plat_get_next_image_ep_info(NON_SECURE);
 		if (ns_ep_info == NULL) {
 			NOTICE("Trusty: non-secure image missing.\n");
 			return -1;
 		}
 		spsr = ns_ep_info->spsr;
 		if (GET_RW(spsr) == MODE_RW_64 && GET_EL(spsr) == MODE_EL2) {
 			spsr &= ~(MODE_EL_MASK << MODE_EL_SHIFT);
 			spsr |= MODE_EL1 << MODE_EL_SHIFT;
 		}
 		if (GET_RW(spsr) == MODE_RW_32 && GET_M32(spsr) == MODE32_hyp) {
 			spsr &= ~(MODE32_MASK << MODE32_SHIFT);
 			spsr |= MODE32_svc << MODE32_SHIFT;
 		}
 		if (spsr != ns_ep_info->spsr) {
 			NOTICE("Trusty: Switch bl33 from EL2 to EL1 (spsr 0x%x -> 0x%x)\n",
 			       ns_ep_info->spsr, spsr);
 			ns_ep_info->spsr = spsr;
 		}
 	}

 	return 0;
 }

 /* Define a SPD runtime service descriptor for fast SMC calls */
 DECLARE_RT_SVC(
 	trusty_fast,

 	OEN_TOS_START,
 	SMC_ENTITY_SECURE_MONITOR,
 	SMC_TYPE_FAST,
 	trusty_setup,
 	trusty_smc_handler
 );

 /* Define a SPD runtime service descriptor for yielding SMC calls */
 DECLARE_RT_SVC(
 	trusty_std,

 	OEN_TAP_START,
 	SMC_ENTITY_SECURE_MONITOR,
 	SMC_TYPE_YIELD,
 	NULL,
 	trusty_smc_handler
 );
	/*
	* Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
	*
	* SPDX-License-Identifier: BSD-3-Clause
	*/

	#include <arch_helpers.h>
	#include <assert.h> /* for context_mgmt.h */
	#include <bl31.h>
	#include <bl_common.h>
	#include <context_mgmt.h>
	#include <debug.h>
	#include <interrupt_mgmt.h>
	#include <platform.h>
	#include <runtime_svc.h>
	#include <stdbool.h>
	#include <string.h>

	#include "sm_err.h"
	#include "smcall.h"

	/* macro to check if Hypervisor is enabled in the HCR_EL2 register */
	#define HYP_ENABLE_FLAG 0x286001

	struct trusty_stack {
	uint8_t space[PLATFORM_STACK_SIZE] __aligned(16);
	uint32_t end;
	};

	struct trusty_cpu_ctx {
	cpu_context_t cpu_ctx;
	void *saved_sp;
	uint32_t saved_security_state;
	int fiq_handler_active;
	uint64_t fiq_handler_pc;
	uint64_t fiq_handler_cpsr;
	uint64_t fiq_handler_sp;
	uint64_t fiq_pc;
	uint64_t fiq_cpsr;
	uint64_t fiq_sp_el1;
	gp_regs_t fiq_gpregs;
	struct trusty_stack secure_stack;
	};

	struct args {
	uint64_t r0;
	uint64_t r1;
	uint64_t r2;
	uint64_t r3;
	uint64_t r4;
	uint64_t r5;
	uint64_t r6;
	uint64_t r7;
	};

	static struct trusty_cpu_ctx trusty_cpu_ctx[PLATFORM_CORE_COUNT];

	struct args trusty_init_context_stack(void *sp, void new_stack);
	struct args trusty_context_switch_helper(void *sp, void smc_params);

	static uint32_t current_vmid;

	static struct trusty_cpu_ctx *get_trusty_ctx(void)
	{
	return &trusty_cpu_ctx[plat_my_core_pos()];
	}

	static uint32_t is_hypervisor_mode(void)
	{
	uint64_t hcr = read_hcr();

	return !!(hcr & HYP_ENABLE_FLAG);
	}

	static struct args trusty_context_switch(uint32_t security_state, uint64_t r0,
	uint64_t r1, uint64_t r2, uint64_t r3)
	{
	struct args ret;
	struct trusty_cpu_ctx *ctx = get_trusty_ctx();
	struct trusty_cpu_ctx *ctx_smc;

	assert(ctx->saved_security_state != security_state);

	ret.r7 = 0;
	if (is_hypervisor_mode()) {
	/* According to the ARM DEN0028A spec, VMID is stored in x7 */
	ctx_smc = cm_get_context(NON_SECURE);
	assert(ctx_smc);
	ret.r7 = SMC_GET_GP(ctx_smc, CTX_GPREG_X7);
	}
	/* r4, r5, r6 reserved for future use. */
	ret.r6 = 0;
	ret.r5 = 0;
	ret.r4 = 0;
	ret.r3 = r3;
	ret.r2 = r2;
	ret.r1 = r1;
	ret.r0 = r0;

	/*
	* To avoid the additional overhead in PSCI flow, skip FP context
	* saving/restoring in case of CPU suspend and resume, asssuming that
	* when it's needed the PSCI caller has preserved FP context before
	* going here.
	*/
	if (r0 != SMC_FC_CPU_SUSPEND && r0 != SMC_FC_CPU_RESUME)
	fpregs_context_save(get_fpregs_ctx(cm_get_context(security_state)));
	cm_el1_sysregs_context_save(security_state);

	ctx->saved_security_state = security_state;
	ret = trusty_context_switch_helper(&ctx->saved_sp, &ret);

	assert(ctx->saved_security_state == !security_state);

	cm_el1_sysregs_context_restore(security_state);
	if (r0 != SMC_FC_CPU_SUSPEND && r0 != SMC_FC_CPU_RESUME)
	fpregs_context_restore(get_fpregs_ctx(cm_get_context(security_state)));

	cm_set_next_eret_context(security_state);

	return ret;
	}

	static uint64_t trusty_fiq_handler(uint32_t id,
	uint32_t flags,
	void *handle,
	void *cookie)
	{
	struct args ret;
	struct trusty_cpu_ctx *ctx = get_trusty_ctx();

	assert(!is_caller_secure(flags));

	ret = trusty_context_switch(NON_SECURE, SMC_FC_FIQ_ENTER, 0, 0, 0);
	if (ret.r0) {
	SMC_RET0(handle);
	}

	if (ctx->fiq_handler_active) {
	INFO("%s: fiq handler already active\n", __func__);
	SMC_RET0(handle);
	}

	ctx->fiq_handler_active = 1;
	memcpy(&ctx->fiq_gpregs, get_gpregs_ctx(handle), sizeof(ctx->fiq_gpregs));
	ctx->fiq_pc = SMC_GET_EL3(handle, CTX_ELR_EL3);
	ctx->fiq_cpsr = SMC_GET_EL3(handle, CTX_SPSR_EL3);
	ctx->fiq_sp_el1 = read_ctx_reg(get_sysregs_ctx(handle), CTX_SP_EL1);

	write_ctx_reg(get_sysregs_ctx(handle), CTX_SP_EL1, ctx->fiq_handler_sp);
	cm_set_elr_spsr_el3(NON_SECURE, ctx->fiq_handler_pc, ctx->fiq_handler_cpsr);

	SMC_RET0(handle);
	}

	static uint64_t trusty_set_fiq_handler(void *handle, uint64_t cpu,
	uint64_t handler, uint64_t stack)
	{
	struct trusty_cpu_ctx *ctx;

	if (cpu >= PLATFORM_CORE_COUNT) {
	ERROR("%s: cpu %lld >= %d\n", __func__, cpu, PLATFORM_CORE_COUNT);
	return SM_ERR_INVALID_PARAMETERS;
	}

	ctx = &trusty_cpu_ctx[cpu];
	ctx->fiq_handler_pc = handler;
	ctx->fiq_handler_cpsr = SMC_GET_EL3(handle, CTX_SPSR_EL3);
	ctx->fiq_handler_sp = stack;

	SMC_RET1(handle, 0);
	}

	static uint64_t trusty_get_fiq_regs(void *handle)
	{
	struct trusty_cpu_ctx *ctx = get_trusty_ctx();
	uint64_t sp_el0 = read_ctx_reg(&ctx->fiq_gpregs, CTX_GPREG_SP_EL0);

	SMC_RET4(handle, ctx->fiq_pc, ctx->fiq_cpsr, sp_el0, ctx->fiq_sp_el1);
	}

	static uint64_t trusty_fiq_exit(void *handle, uint64_t x1, uint64_t x2, uint64_t x3)
	{
	struct args ret;
	struct trusty_cpu_ctx *ctx = get_trusty_ctx();

	if (!ctx->fiq_handler_active) {
	NOTICE("%s: fiq handler not active\n", __func__);
	SMC_RET1(handle, SM_ERR_INVALID_PARAMETERS);
	}

	ret = trusty_context_switch(NON_SECURE, SMC_FC_FIQ_EXIT, 0, 0, 0);
	if (ret.r0 != 1) {
	INFO("%s(%p) SMC_FC_FIQ_EXIT returned unexpected value, %lld\n",
	__func__, handle, ret.r0);
	}

	/*
	* Restore register state to state recorded on fiq entry.
	*
	* x0, sp_el1, pc and cpsr need to be restored because el1 cannot
	* restore them.
	*
	* x1-x4 and x8-x17 need to be restored here because smc_handler64
	* corrupts them (el1 code also restored them).
	*/
	memcpy(get_gpregs_ctx(handle), &ctx->fiq_gpregs, sizeof(ctx->fiq_gpregs));
	ctx->fiq_handler_active = 0;
	write_ctx_reg(get_sysregs_ctx(handle), CTX_SP_EL1, ctx->fiq_sp_el1);
	cm_set_elr_spsr_el3(NON_SECURE, ctx->fiq_pc, ctx->fiq_cpsr);

	SMC_RET0(handle);
	}

	static uintptr_t trusty_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)
	{
	struct args ret;
	uint32_t vmid = 0;
	entry_point_info_t *ep_info = bl31_plat_get_next_image_ep_info(SECURE);

	/*
	* Return success for SET_ROT_PARAMS if Trusty is not present, as
	* Verified Boot is not even supported and returning success here
	* would not compromise the boot process.
	*/
	if (!ep_info && (smc_fid == SMC_YC_SET_ROT_PARAMS)) {
	SMC_RET1(handle, 0);
	} else if (!ep_info) {
	SMC_RET1(handle, SMC_UNK);
	}

	if (is_caller_secure(flags)) {
	if (smc_fid == SMC_YC_NS_RETURN) {
	ret = trusty_context_switch(SECURE, x1, 0, 0, 0);
	SMC_RET8(handle, ret.r0, ret.r1, ret.r2, ret.r3,
	ret.r4, ret.r5, ret.r6, ret.r7);
	}
	INFO("%s (0x%x, 0x%lx, 0x%lx, 0x%lx, 0x%lx, %p, %p, 0x%lx) \
	cpu %d, unknown smc\n",
	__func__, smc_fid, x1, x2, x3, x4, cookie, handle, flags,
	plat_my_core_pos());
	SMC_RET1(handle, SMC_UNK);
	} else {
	switch (smc_fid) {
	case SMC_FC64_SET_FIQ_HANDLER:
	return trusty_set_fiq_handler(handle, x1, x2, x3);
	case SMC_FC64_GET_FIQ_REGS:
	return trusty_get_fiq_regs(handle);
	case SMC_FC_FIQ_EXIT:
	return trusty_fiq_exit(handle, x1, x2, x3);
	default:
	if (is_hypervisor_mode())
	vmid = SMC_GET_GP(handle, CTX_GPREG_X7);

	if ((current_vmid != 0) && (current_vmid != vmid)) {
	/* This message will cause SMC mechanism
	* abnormal in multi-guest environment.
	* Change it to WARN in case you need it.
	*/
	VERBOSE("Previous SMC not finished.\n");
	SMC_RET1(handle, SM_ERR_BUSY);
	}
	current_vmid = vmid;
	ret = trusty_context_switch(NON_SECURE, smc_fid, x1,
	x2, x3);
	current_vmid = 0;
	SMC_RET1(handle, ret.r0);
	}
	}
	}

	static int32_t trusty_init(void)
	{
	void el3_exit(void);
	entry_point_info_t *ep_info;
	struct args zero_args = {0};
	struct trusty_cpu_ctx *ctx = get_trusty_ctx();
	uint32_t cpu = plat_my_core_pos();
	int reg_width = GET_RW(read_ctx_reg(get_el3state_ctx(&ctx->cpu_ctx),
	CTX_SPSR_EL3));

	/*
	* Get information about the Trusty image. Its absence is a critical
	* failure.
	*/
	ep_info = bl31_plat_get_next_image_ep_info(SECURE);
	assert(ep_info);

	fpregs_context_save(get_fpregs_ctx(cm_get_context(NON_SECURE)));
	cm_el1_sysregs_context_save(NON_SECURE);

	cm_set_context(&ctx->cpu_ctx, SECURE);
	cm_init_my_context(ep_info);

	/*
	* Adjust secondary cpu entry point for 32 bit images to the
	* end of exeption vectors
	*/
	if ((cpu != 0) && (reg_width == MODE_RW_32)) {
	INFO("trusty: cpu %d, adjust entry point to 0x%lx\n",
	cpu, ep_info->pc + (1U << 5));
	cm_set_elr_el3(SECURE, ep_info->pc + (1U << 5));
	}

	cm_el1_sysregs_context_restore(SECURE);
	fpregs_context_restore(get_fpregs_ctx(cm_get_context(SECURE)));
	cm_set_next_eret_context(SECURE);

	ctx->saved_security_state = ~0; /* initial saved state is invalid */
	trusty_init_context_stack(&ctx->saved_sp, &ctx->secure_stack.end);

	trusty_context_switch_helper(&ctx->saved_sp, &zero_args);

	cm_el1_sysregs_context_restore(NON_SECURE);
	fpregs_context_restore(get_fpregs_ctx(cm_get_context(NON_SECURE)));
	cm_set_next_eret_context(NON_SECURE);

	return 1;
	}

	static void trusty_cpu_suspend(uint32_t off)
	{
	struct args ret;

	ret = trusty_context_switch(NON_SECURE, SMC_FC_CPU_SUSPEND, off, 0, 0);
	if (ret.r0 != 0) {
	INFO("%s: cpu %d, SMC_FC_CPU_SUSPEND returned unexpected value, %lld\n",
	__func__, plat_my_core_pos(), ret.r0);
	}
	}

	static void trusty_cpu_resume(uint32_t on)
	{
	struct args ret;

	ret = trusty_context_switch(NON_SECURE, SMC_FC_CPU_RESUME, on, 0, 0);
	if (ret.r0 != 0) {
	INFO("%s: cpu %d, SMC_FC_CPU_RESUME returned unexpected value, %lld\n",
	__func__, plat_my_core_pos(), ret.r0);
	}
	}

	static int32_t trusty_cpu_off_handler(u_register_t unused)
	{
	trusty_cpu_suspend(1);

	return 0;
	}

	static void trusty_cpu_on_finish_handler(u_register_t unused)
	{
	struct trusty_cpu_ctx *ctx = get_trusty_ctx();

	if (!ctx->saved_sp) {
	trusty_init();
	} else {
	trusty_cpu_resume(1);
	}
	}

	static void trusty_cpu_suspend_handler(u_register_t unused)
	{
	trusty_cpu_suspend(0);
	}

	static void trusty_cpu_suspend_finish_handler(u_register_t unused)
	{
	trusty_cpu_resume(0);
	}

	static const spd_pm_ops_t trusty_pm = {
	.svc_off = trusty_cpu_off_handler,
	.svc_suspend = trusty_cpu_suspend_handler,
	.svc_on_finish = trusty_cpu_on_finish_handler,
	.svc_suspend_finish = trusty_cpu_suspend_finish_handler,
	};

	void plat_trusty_set_boot_args(aapcs64_params_t *args);

	#ifdef TSP_SEC_MEM_SIZE
	#pragma weak plat_trusty_set_boot_args
	void plat_trusty_set_boot_args(aapcs64_params_t *args)
	{
	args->arg0 = TSP_SEC_MEM_SIZE;
	}
	#endif

	static int32_t trusty_setup(void)
	{
	entry_point_info_t *ep_info;
	uint32_t instr;
	uint32_t flags;
	int ret;
	bool aarch32 = false;

	/* Get trusty's entry point info */
	ep_info = bl31_plat_get_next_image_ep_info(SECURE);
	if (!ep_info) {
	INFO("Trusty image missing.\n");
	return -1;
	}

	instr = (uint32_t )ep_info->pc;

	if (instr >> 24 == 0xeaU) {
	INFO("trusty: Found 32 bit image\n");
	aarch32 = true;
	} else if (instr >> 8 == 0xd53810U \|\| instr >> 16 == 0x9400U) {
	INFO("trusty: Found 64 bit image\n");
	} else {
	NOTICE("trusty: Found unknown image, 0x%x\n", instr);
	}

	SET_PARAM_HEAD(ep_info, PARAM_EP, VERSION_1, SECURE \| EP_ST_ENABLE);
	if (!aarch32)
	ep_info->spsr = SPSR_64(MODE_EL1, MODE_SP_ELX,
	DISABLE_ALL_EXCEPTIONS);
	else
	ep_info->spsr = SPSR_MODE32(MODE32_svc, SPSR_T_ARM,
	SPSR_E_LITTLE,
	DAIF_FIQ_BIT \|
	DAIF_IRQ_BIT \|
	DAIF_ABT_BIT);
	(void)memset(&ep_info->args, 0, sizeof(ep_info->args));
	plat_trusty_set_boot_args(&ep_info->args);

	/* register init handler */
	bl31_register_bl32_init(trusty_init);

	/* register power management hooks */
	psci_register_spd_pm_hook(&trusty_pm);

	/* register interrupt handler */
	flags = 0;
	set_interrupt_rm_flag(flags, NON_SECURE);
	ret = register_interrupt_type_handler(INTR_TYPE_S_EL1,
	trusty_fiq_handler,
	flags);
	if (ret)
	ERROR("trusty: failed to register fiq handler, ret = %d\n", ret);

	if (aarch32) {
	entry_point_info_t *ns_ep_info;
	uint32_t spsr;

	ns_ep_info = bl31_plat_get_next_image_ep_info(NON_SECURE);
	if (ns_ep_info == NULL) {
	NOTICE("Trusty: non-secure image missing.\n");
	return -1;
	}
	spsr = ns_ep_info->spsr;
	if (GET_RW(spsr) == MODE_RW_64 && GET_EL(spsr) == MODE_EL2) {
	spsr &= ~(MODE_EL_MASK << MODE_EL_SHIFT);
	spsr \|= MODE_EL1 << MODE_EL_SHIFT;
	}
	if (GET_RW(spsr) == MODE_RW_32 && GET_M32(spsr) == MODE32_hyp) {
	spsr &= ~(MODE32_MASK << MODE32_SHIFT);
	spsr \|= MODE32_svc << MODE32_SHIFT;
	}
	if (spsr != ns_ep_info->spsr) {
	NOTICE("Trusty: Switch bl33 from EL2 to EL1 (spsr 0x%x -> 0x%x)\n",
	ns_ep_info->spsr, spsr);
	ns_ep_info->spsr = spsr;
	}
	}

	return 0;
	}

	/* Define a SPD runtime service descriptor for fast SMC calls */
	DECLARE_RT_SVC(
	trusty_fast,

	OEN_TOS_START,
	SMC_ENTITY_SECURE_MONITOR,
	SMC_TYPE_FAST,
	trusty_setup,
	trusty_smc_handler
	);

	/* Define a SPD runtime service descriptor for yielding SMC calls */
	DECLARE_RT_SVC(
	trusty_std,

	OEN_TAP_START,
	SMC_ENTITY_SECURE_MONITOR,
	SMC_TYPE_YIELD,
	NULL,
	trusty_smc_handler
	);