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      1 /*
      2  * Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
      3  *
      4  * SPDX-License-Identifier: BSD-3-Clause
      5  */
      6 
      7 /*******************************************************************************
      8  * This is the Secure Payload Dispatcher (SPD). The dispatcher is meant to be a
      9  * plug-in component to the Secure Monitor, registered as a runtime service. The
     10  * SPD is expected to be a functional extension of the Secure Payload (SP) that
     11  * executes in Secure EL1. The Secure Monitor will delegate all SMCs targeting
     12  * the Trusted OS/Applications range to the dispatcher. The SPD will either
     13  * handle the request locally or delegate it to the Secure Payload. It is also
     14  * responsible for initialising and maintaining communication with the SP.
     15  ******************************************************************************/
     16 #include <arch_helpers.h>
     17 #include <assert.h>
     18 #include <bl31.h>
     19 #include <bl_common.h>
     20 #include <context_mgmt.h>
     21 #include <debug.h>
     22 #include <errno.h>
     23 #include <platform.h>
     24 #include <runtime_svc.h>
     25 #include <stddef.h>
     26 #include <tlk.h>
     27 #include <uuid.h>
     28 #include "tlkd_private.h"
     29 
     30 extern const spd_pm_ops_t tlkd_pm_ops;
     31 
     32 /*******************************************************************************
     33  * Per-cpu Secure Payload state
     34  ******************************************************************************/
     35 tlk_context_t tlk_ctx;
     36 
     37 /*******************************************************************************
     38  * CPU number on which TLK booted up
     39  ******************************************************************************/
     40 static uint32_t boot_cpu;
     41 
     42 /* TLK UID: RFC-4122 compliant UUID (version-5, sha-1) */
     43 DEFINE_SVC_UUID(tlk_uuid,
     44 		0xbd11e9c9, 0x2bba, 0x52ee, 0xb1, 0x72,
     45 		0x46, 0x1f, 0xba, 0x97, 0x7f, 0x63);
     46 
     47 int32_t tlkd_init(void);
     48 
     49 /*******************************************************************************
     50  * Secure Payload Dispatcher setup. The SPD finds out the SP entrypoint and type
     51  * (aarch32/aarch64) if not already known and initialises the context for entry
     52  * into the SP for its initialisation.
     53  ******************************************************************************/
     54 int32_t tlkd_setup(void)
     55 {
     56 	entry_point_info_t *tlk_ep_info;
     57 
     58 	/*
     59 	 * Get information about the Secure Payload (BL32) image. Its
     60 	 * absence is a critical failure.
     61 	 */
     62 	tlk_ep_info = bl31_plat_get_next_image_ep_info(SECURE);
     63 	if (!tlk_ep_info) {
     64 		WARN("No SP provided. Booting device without SP"
     65 			" initialization. SMC`s destined for SP"
     66 			" will return SMC_UNK\n");
     67 		return 1;
     68 	}
     69 
     70 	/*
     71 	 * If there's no valid entry point for SP, we return a non-zero value
     72 	 * signalling failure initializing the service. We bail out without
     73 	 * registering any handlers
     74 	 */
     75 	if (!tlk_ep_info->pc)
     76 		return 1;
     77 
     78 	/*
     79 	 * Inspect the SP image's SPSR and determine it's execution state
     80 	 * i.e whether AArch32 or AArch64.
     81 	 */
     82 	tlkd_init_tlk_ep_state(tlk_ep_info,
     83 		(tlk_ep_info->spsr >> MODE_RW_SHIFT) & MODE_RW_MASK,
     84 		tlk_ep_info->pc,
     85 		&tlk_ctx);
     86 
     87 	/*
     88 	 * All TLK SPD initialization done. Now register our init function
     89 	 * with BL31 for deferred invocation
     90 	 */
     91 	bl31_register_bl32_init(&tlkd_init);
     92 
     93 	return 0;
     94 }
     95 
     96 /*******************************************************************************
     97  * This function passes control to the Secure Payload image (BL32) for the first
     98  * time on the primary cpu after a cold boot. It assumes that a valid secure
     99  * context has already been created by tlkd_setup() which can be directly
    100  * used. This function performs a synchronous entry into the Secure payload.
    101  * The SP passes control back to this routine through a SMC.
    102  ******************************************************************************/
    103 int32_t tlkd_init(void)
    104 {
    105 	entry_point_info_t *tlk_entry_point;
    106 
    107 	/*
    108 	 * Get information about the Secure Payload (BL32) image. Its
    109 	 * absence is a critical failure.
    110 	 */
    111 	tlk_entry_point = bl31_plat_get_next_image_ep_info(SECURE);
    112 	assert(tlk_entry_point);
    113 
    114 	cm_init_my_context(tlk_entry_point);
    115 
    116 	/*
    117 	 * TLK runs only on a single CPU. Store the value of the boot
    118 	 * CPU for sanity checking later.
    119 	 */
    120 	boot_cpu = plat_my_core_pos();
    121 
    122 	/*
    123 	 * Arrange for an entry into the test secure payload.
    124 	 */
    125 	return tlkd_synchronous_sp_entry(&tlk_ctx);
    126 }
    127 
    128 /*******************************************************************************
    129  * This function is responsible for handling all SMCs in the Trusted OS/App
    130  * range from the non-secure state as defined in the SMC Calling Convention
    131  * Document. It is also responsible for communicating with the Secure payload
    132  * to delegate work and return results back to the non-secure state. Lastly it
    133  * will also return any information that the secure payload needs to do the
    134  * work assigned to it.
    135  ******************************************************************************/
    136 uint64_t tlkd_smc_handler(uint32_t smc_fid,
    137 			 uint64_t x1,
    138 			 uint64_t x2,
    139 			 uint64_t x3,
    140 			 uint64_t x4,
    141 			 void *cookie,
    142 			 void *handle,
    143 			 uint64_t flags)
    144 {
    145 	cpu_context_t *ns_cpu_context;
    146 	gp_regs_t *gp_regs;
    147 	uint32_t ns;
    148 	uint64_t par;
    149 
    150 	/* Passing a NULL context is a critical programming error */
    151 	assert(handle);
    152 
    153 	/* These SMCs are only supported by a single CPU */
    154 	if (boot_cpu != plat_my_core_pos())
    155 		SMC_RET1(handle, SMC_UNK);
    156 
    157 	/* Determine which security state this SMC originated from */
    158 	ns = is_caller_non_secure(flags);
    159 
    160 	switch (smc_fid) {
    161 
    162 	/*
    163 	 * This function ID is used by SP to indicate that it was
    164 	 * preempted by a non-secure world IRQ.
    165 	 */
    166 	case TLK_PREEMPTED:
    167 
    168 		if (ns)
    169 			SMC_RET1(handle, SMC_UNK);
    170 
    171 		assert(handle == cm_get_context(SECURE));
    172 		cm_el1_sysregs_context_save(SECURE);
    173 
    174 		/* Get a reference to the non-secure context */
    175 		ns_cpu_context = cm_get_context(NON_SECURE);
    176 		assert(ns_cpu_context);
    177 
    178 		/*
    179 		 * Restore non-secure state. There is no need to save the
    180 		 * secure system register context since the SP was supposed
    181 		 * to preserve it during S-EL1 interrupt handling.
    182 		 */
    183 		cm_el1_sysregs_context_restore(NON_SECURE);
    184 		cm_set_next_eret_context(NON_SECURE);
    185 
    186 		SMC_RET1(ns_cpu_context, x1);
    187 
    188 	/*
    189 	 * This is a request from the non-secure context to:
    190 	 *
    191 	 * a. register shared memory with the SP for storing it's
    192 	 *    activity logs.
    193 	 * b. register shared memory with the SP for passing args
    194 	 *    required for maintaining sessions with the Trusted
    195 	 *    Applications.
    196 	 * c. open/close sessions
    197 	 * d. issue commands to the Trusted Apps
    198 	 * e. resume the preempted yielding SMC call.
    199 	 */
    200 	case TLK_REGISTER_LOGBUF:
    201 	case TLK_REGISTER_REQBUF:
    202 	case TLK_OPEN_TA_SESSION:
    203 	case TLK_CLOSE_TA_SESSION:
    204 	case TLK_TA_LAUNCH_OP:
    205 	case TLK_TA_SEND_EVENT:
    206 	case TLK_RESUME_FID:
    207 
    208 		if (!ns)
    209 			SMC_RET1(handle, SMC_UNK);
    210 
    211 		/*
    212 		 * This is a fresh request from the non-secure client.
    213 		 * The parameters are in x1 and x2. Figure out which
    214 		 * registers need to be preserved, save the non-secure
    215 		 * state and send the request to the secure payload.
    216 		 */
    217 		assert(handle == cm_get_context(NON_SECURE));
    218 
    219 		/*
    220 		 * Check if we are already processing a yielding SMC
    221 		 * call. Of all the supported fids, only the "resume"
    222 		 * fid expects the flag to be set.
    223 		 */
    224 		if (smc_fid == TLK_RESUME_FID) {
    225 			if (!get_yield_smc_active_flag(tlk_ctx.state))
    226 				SMC_RET1(handle, SMC_UNK);
    227 		} else {
    228 			if (get_yield_smc_active_flag(tlk_ctx.state))
    229 				SMC_RET1(handle, SMC_UNK);
    230 		}
    231 
    232 		cm_el1_sysregs_context_save(NON_SECURE);
    233 
    234 		/*
    235 		 * Verify if there is a valid context to use.
    236 		 */
    237 		assert(&tlk_ctx.cpu_ctx == cm_get_context(SECURE));
    238 
    239 		/*
    240 		 * Mark the SP state as active.
    241 		 */
    242 		set_yield_smc_active_flag(tlk_ctx.state);
    243 
    244 		/*
    245 		 * We are done stashing the non-secure context. Ask the
    246 		 * secure payload to do the work now.
    247 		 */
    248 		cm_el1_sysregs_context_restore(SECURE);
    249 		cm_set_next_eret_context(SECURE);
    250 
    251 		/*
    252 		 * TLK is a 32-bit Trusted OS and so expects the SMC
    253 		 * arguments via r0-r7. TLK expects the monitor frame
    254 		 * registers to be 64-bits long. Hence, we pass x0 in
    255 		 * r0-r1, x1 in r2-r3, x3 in r4-r5 and x4 in r6-r7.
    256 		 *
    257 		 * As smc_fid is a uint32 value, r1 contains 0.
    258 		 */
    259 		gp_regs = get_gpregs_ctx(&tlk_ctx.cpu_ctx);
    260 		write_ctx_reg(gp_regs, CTX_GPREG_X4, (uint32_t)x2);
    261 		write_ctx_reg(gp_regs, CTX_GPREG_X5, (uint32_t)(x2 >> 32));
    262 		write_ctx_reg(gp_regs, CTX_GPREG_X6, (uint32_t)x3);
    263 		write_ctx_reg(gp_regs, CTX_GPREG_X7, (uint32_t)(x3 >> 32));
    264 		SMC_RET4(&tlk_ctx.cpu_ctx, smc_fid, 0, (uint32_t)x1,
    265 			(uint32_t)(x1 >> 32));
    266 
    267 	/*
    268 	 * Translate NS/EL1-S virtual addresses.
    269 	 *
    270 	 * x1 = virtual address
    271 	 * x3 = type (NS/S)
    272 	 *
    273 	 * Returns PA:lo in r0, PA:hi in r1.
    274 	 */
    275 	case TLK_VA_TRANSLATE:
    276 
    277 		/* Should be invoked only by secure world */
    278 		if (ns)
    279 			SMC_RET1(handle, SMC_UNK);
    280 
    281 		/* NS virtual addresses are 64-bit long */
    282 		if (x3 & TLK_TRANSLATE_NS_VADDR)
    283 			x1 = (uint32_t)x1 | (x2 << 32);
    284 
    285 		if (!x1)
    286 			SMC_RET1(handle, SMC_UNK);
    287 
    288 		/*
    289 		 * TODO: Sanity check x1. This would require platform
    290 		 * support.
    291 		 */
    292 
    293 		/* virtual address and type: ns/s */
    294 		par = tlkd_va_translate(x1, x3);
    295 
    296 		/* return physical address in r0-r1 */
    297 		SMC_RET4(handle, (uint32_t)par, (uint32_t)(par >> 32), 0, 0);
    298 
    299 	/*
    300 	 * This is a request from the SP to mark completion of
    301 	 * a yielding function ID.
    302 	 */
    303 	case TLK_REQUEST_DONE:
    304 		if (ns)
    305 			SMC_RET1(handle, SMC_UNK);
    306 
    307 		/*
    308 		 * Mark the SP state as inactive.
    309 		 */
    310 		clr_yield_smc_active_flag(tlk_ctx.state);
    311 
    312 		/* Get a reference to the non-secure context */
    313 		ns_cpu_context = cm_get_context(NON_SECURE);
    314 		assert(ns_cpu_context);
    315 
    316 		/*
    317 		 * This is a request completion SMC and we must switch to
    318 		 * the non-secure world to pass the result.
    319 		 */
    320 		cm_el1_sysregs_context_save(SECURE);
    321 
    322 		/*
    323 		 * We are done stashing the secure context. Switch to the
    324 		 * non-secure context and return the result.
    325 		 */
    326 		cm_el1_sysregs_context_restore(NON_SECURE);
    327 		cm_set_next_eret_context(NON_SECURE);
    328 		SMC_RET1(ns_cpu_context, x1);
    329 
    330 	/*
    331 	 * This function ID is used only by the SP to indicate it has
    332 	 * finished initialising itself after a cold boot
    333 	 */
    334 	case TLK_ENTRY_DONE:
    335 		if (ns)
    336 			SMC_RET1(handle, SMC_UNK);
    337 
    338 		/*
    339 		 * SP has been successfully initialized. Register power
    340 		 * managemnt hooks with PSCI
    341 		 */
    342 		psci_register_spd_pm_hook(&tlkd_pm_ops);
    343 
    344 		/*
    345 		 * TLK reports completion. The SPD must have initiated
    346 		 * the original request through a synchronous entry
    347 		 * into the SP. Jump back to the original C runtime
    348 		 * context.
    349 		 */
    350 		tlkd_synchronous_sp_exit(&tlk_ctx, x1);
    351 
    352 	/*
    353 	 * These function IDs are used only by TLK to indicate it has
    354 	 * finished:
    355 	 * 1. suspending itself after an earlier psci cpu_suspend
    356 	 *    request.
    357 	 * 2. resuming itself after an earlier psci cpu_suspend
    358 	 *    request.
    359 	 * 3. powering down after an earlier psci system_off/system_reset
    360 	 *    request.
    361 	 */
    362 	case TLK_SUSPEND_DONE:
    363 	case TLK_RESUME_DONE:
    364 	case TLK_SYSTEM_OFF_DONE:
    365 
    366 		if (ns)
    367 			SMC_RET1(handle, SMC_UNK);
    368 
    369 		/*
    370 		 * TLK reports completion. TLKD must have initiated the
    371 		 * original request through a synchronous entry into the SP.
    372 		 * Jump back to the original C runtime context, and pass x1 as
    373 		 * return value to the caller
    374 		 */
    375 		tlkd_synchronous_sp_exit(&tlk_ctx, x1);
    376 
    377 	/*
    378 	 * Return the number of service function IDs implemented to
    379 	 * provide service to non-secure
    380 	 */
    381 	case TOS_CALL_COUNT:
    382 		SMC_RET1(handle, TLK_NUM_FID);
    383 
    384 	/*
    385 	 * Return TLK's UID to the caller
    386 	 */
    387 	case TOS_UID:
    388 		SMC_UUID_RET(handle, tlk_uuid);
    389 
    390 	/*
    391 	 * Return the version of current implementation
    392 	 */
    393 	case TOS_CALL_VERSION:
    394 		SMC_RET2(handle, TLK_VERSION_MAJOR, TLK_VERSION_MINOR);
    395 
    396 	default:
    397 		break;
    398 	}
    399 
    400 	SMC_RET1(handle, SMC_UNK);
    401 }
    402 
    403 /* Define a SPD runtime service descriptor for fast SMC calls */
    404 DECLARE_RT_SVC(
    405 	tlkd_tos_fast,
    406 
    407 	OEN_TOS_START,
    408 	OEN_TOS_END,
    409 	SMC_TYPE_FAST,
    410 	tlkd_setup,
    411 	tlkd_smc_handler
    412 );
    413 
    414 /* Define a SPD runtime service descriptor for yielding SMC calls */
    415 DECLARE_RT_SVC(
    416 	tlkd_tos_std,
    417 
    418 	OEN_TOS_START,
    419 	OEN_TOS_END,
    420 	SMC_TYPE_YIELD,
    421 	NULL,
    422 	tlkd_smc_handler
    423 );
    424 
    425 /* Define a SPD runtime service descriptor for fast SMC calls */
    426 DECLARE_RT_SVC(
    427 	tlkd_tap_fast,
    428 
    429 	OEN_TAP_START,
    430 	OEN_TAP_END,
    431 	SMC_TYPE_FAST,
    432 	NULL,
    433 	tlkd_smc_handler
    434 );
    435 
    436 /* Define a SPD runtime service descriptor for yielding SMC calls */
    437 DECLARE_RT_SVC(
    438 	tlkd_tap_std,
    439 
    440 	OEN_TAP_START,
    441 	OEN_TAP_END,
    442 	SMC_TYPE_YIELD,
    443 	NULL,
    444 	tlkd_smc_handler
    445 );
    446