xref: /rk3399_ARM-atf/lib/el3_runtime/aarch64/context_mgmt.c (revision 023f1bed1dde23564e3b66a99c4a45b09e38992b)
1 /*
2  * Copyright (c) 2013-2023, Arm Limited and Contributors. All rights reserved.
3  * Copyright (c) 2022, NVIDIA Corporation. All rights reserved.
4  *
5  * SPDX-License-Identifier: BSD-3-Clause
6  */
7 
8 #include <assert.h>
9 #include <stdbool.h>
10 #include <string.h>
11 
12 #include <platform_def.h>
13 
14 #include <arch.h>
15 #include <arch_helpers.h>
16 #include <arch_features.h>
17 #include <bl31/interrupt_mgmt.h>
18 #include <common/bl_common.h>
19 #include <common/debug.h>
20 #include <context.h>
21 #include <drivers/arm/gicv3.h>
22 #include <lib/el3_runtime/context_mgmt.h>
23 #include <lib/el3_runtime/pubsub_events.h>
24 #include <lib/extensions/amu.h>
25 #include <lib/extensions/brbe.h>
26 #include <lib/extensions/mpam.h>
27 #include <lib/extensions/sme.h>
28 #include <lib/extensions/spe.h>
29 #include <lib/extensions/sve.h>
30 #include <lib/extensions/sys_reg_trace.h>
31 #include <lib/extensions/trbe.h>
32 #include <lib/extensions/trf.h>
33 #include <lib/utils.h>
34 
35 #if ENABLE_FEAT_TWED
36 /* Make sure delay value fits within the range(0-15) */
37 CASSERT(((TWED_DELAY & ~SCR_TWEDEL_MASK) == 0U), assert_twed_delay_value_check);
38 #endif /* ENABLE_FEAT_TWED */
39 
40 static void manage_extensions_secure(cpu_context_t *ctx);
41 
42 static void setup_el1_context(cpu_context_t *ctx, const struct entry_point_info *ep)
43 {
44 	u_register_t sctlr_elx, actlr_elx;
45 
46 	/*
47 	 * Initialise SCTLR_EL1 to the reset value corresponding to the target
48 	 * execution state setting all fields rather than relying on the hw.
49 	 * Some fields have architecturally UNKNOWN reset values and these are
50 	 * set to zero.
51 	 *
52 	 * SCTLR.EE: Endianness is taken from the entrypoint attributes.
53 	 *
54 	 * SCTLR.M, SCTLR.C and SCTLR.I: These fields must be zero (as
55 	 * required by PSCI specification)
56 	 */
57 	sctlr_elx = (EP_GET_EE(ep->h.attr) != 0U) ? SCTLR_EE_BIT : 0UL;
58 	if (GET_RW(ep->spsr) == MODE_RW_64) {
59 		sctlr_elx |= SCTLR_EL1_RES1;
60 	} else {
61 		/*
62 		 * If the target execution state is AArch32 then the following
63 		 * fields need to be set.
64 		 *
65 		 * SCTRL_EL1.nTWE: Set to one so that EL0 execution of WFE
66 		 *  instructions are not trapped to EL1.
67 		 *
68 		 * SCTLR_EL1.nTWI: Set to one so that EL0 execution of WFI
69 		 *  instructions are not trapped to EL1.
70 		 *
71 		 * SCTLR_EL1.CP15BEN: Set to one to enable EL0 execution of the
72 		 *  CP15DMB, CP15DSB, and CP15ISB instructions.
73 		 */
74 		sctlr_elx |= SCTLR_AARCH32_EL1_RES1 | SCTLR_CP15BEN_BIT
75 					| SCTLR_NTWI_BIT | SCTLR_NTWE_BIT;
76 	}
77 
78 #if ERRATA_A75_764081
79 	/*
80 	 * If workaround of errata 764081 for Cortex-A75 is used then set
81 	 * SCTLR_EL1.IESB to enable Implicit Error Synchronization Barrier.
82 	 */
83 	sctlr_elx |= SCTLR_IESB_BIT;
84 #endif
85 	/* Store the initialised SCTLR_EL1 value in the cpu_context */
86 	write_ctx_reg(get_el1_sysregs_ctx(ctx), CTX_SCTLR_EL1, sctlr_elx);
87 
88 	/*
89 	 * Base the context ACTLR_EL1 on the current value, as it is
90 	 * implementation defined. The context restore process will write
91 	 * the value from the context to the actual register and can cause
92 	 * problems for processor cores that don't expect certain bits to
93 	 * be zero.
94 	 */
95 	actlr_elx = read_actlr_el1();
96 	write_ctx_reg((get_el1_sysregs_ctx(ctx)), (CTX_ACTLR_EL1), (actlr_elx));
97 }
98 
99 /******************************************************************************
100  * This function performs initializations that are specific to SECURE state
101  * and updates the cpu context specified by 'ctx'.
102  *****************************************************************************/
103 static void setup_secure_context(cpu_context_t *ctx, const struct entry_point_info *ep)
104 {
105 	u_register_t scr_el3;
106 	el3_state_t *state;
107 
108 	state = get_el3state_ctx(ctx);
109 	scr_el3 = read_ctx_reg(state, CTX_SCR_EL3);
110 
111 #if defined(IMAGE_BL31) && !defined(SPD_spmd)
112 	/*
113 	 * SCR_EL3.IRQ, SCR_EL3.FIQ: Enable the physical FIQ and IRQ routing as
114 	 * indicated by the interrupt routing model for BL31.
115 	 */
116 	scr_el3 |= get_scr_el3_from_routing_model(SECURE);
117 #endif
118 
119 #if !CTX_INCLUDE_MTE_REGS || ENABLE_ASSERTIONS
120 	/* Get Memory Tagging Extension support level */
121 	unsigned int mte = get_armv8_5_mte_support();
122 #endif
123 	/*
124 	 * Allow access to Allocation Tags when CTX_INCLUDE_MTE_REGS
125 	 * is set, or when MTE is only implemented at EL0.
126 	 */
127 #if CTX_INCLUDE_MTE_REGS
128 	assert((mte == MTE_IMPLEMENTED_ELX) || (mte == MTE_IMPLEMENTED_ASY));
129 	scr_el3 |= SCR_ATA_BIT;
130 #else
131 	if (mte == MTE_IMPLEMENTED_EL0) {
132 		scr_el3 |= SCR_ATA_BIT;
133 	}
134 #endif /* CTX_INCLUDE_MTE_REGS */
135 
136 	/* Enable S-EL2 if the next EL is EL2 and S-EL2 is present */
137 	if ((GET_EL(ep->spsr) == MODE_EL2) && is_armv8_4_sel2_present()) {
138 		if (GET_RW(ep->spsr) != MODE_RW_64) {
139 			ERROR("S-EL2 can not be used in AArch32\n.");
140 			panic();
141 		}
142 
143 		scr_el3 |= SCR_EEL2_BIT;
144 	}
145 
146 	write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
147 
148 	/*
149 	 * Initialize EL1 context registers unless SPMC is running
150 	 * at S-EL2.
151 	 */
152 #if !SPMD_SPM_AT_SEL2
153 	setup_el1_context(ctx, ep);
154 #endif
155 
156 	manage_extensions_secure(ctx);
157 }
158 
159 #if ENABLE_RME
160 /******************************************************************************
161  * This function performs initializations that are specific to REALM state
162  * and updates the cpu context specified by 'ctx'.
163  *****************************************************************************/
164 static void setup_realm_context(cpu_context_t *ctx, const struct entry_point_info *ep)
165 {
166 	u_register_t scr_el3;
167 	el3_state_t *state;
168 
169 	state = get_el3state_ctx(ctx);
170 	scr_el3 = read_ctx_reg(state, CTX_SCR_EL3);
171 
172 	scr_el3 |= SCR_NS_BIT | SCR_NSE_BIT;
173 
174 #if ENABLE_FEAT_CSV2_2
175 	/* Enable access to the SCXTNUM_ELx registers. */
176 	scr_el3 |= SCR_EnSCXT_BIT;
177 #endif
178 
179 	write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
180 }
181 #endif /* ENABLE_RME */
182 
183 /******************************************************************************
184  * This function performs initializations that are specific to NON-SECURE state
185  * and updates the cpu context specified by 'ctx'.
186  *****************************************************************************/
187 static void setup_ns_context(cpu_context_t *ctx, const struct entry_point_info *ep)
188 {
189 	u_register_t scr_el3;
190 	el3_state_t *state;
191 
192 	state = get_el3state_ctx(ctx);
193 	scr_el3 = read_ctx_reg(state, CTX_SCR_EL3);
194 
195 	/* SCR_NS: Set the NS bit */
196 	scr_el3 |= SCR_NS_BIT;
197 
198 #if !CTX_INCLUDE_PAUTH_REGS
199 	/*
200 	 * If the pointer authentication registers aren't saved during world
201 	 * switches the value of the registers can be leaked from the Secure to
202 	 * the Non-secure world. To prevent this, rather than enabling pointer
203 	 * authentication everywhere, we only enable it in the Non-secure world.
204 	 *
205 	 * If the Secure world wants to use pointer authentication,
206 	 * CTX_INCLUDE_PAUTH_REGS must be set to 1.
207 	 */
208 	scr_el3 |= SCR_API_BIT | SCR_APK_BIT;
209 #endif /* !CTX_INCLUDE_PAUTH_REGS */
210 
211 	/* Allow access to Allocation Tags when MTE is implemented. */
212 	scr_el3 |= SCR_ATA_BIT;
213 
214 #if HANDLE_EA_EL3_FIRST_NS
215 	/* SCR_EL3.EA: Route External Abort and SError Interrupt to EL3. */
216 	scr_el3 |= SCR_EA_BIT;
217 #endif
218 
219 #if RAS_TRAP_NS_ERR_REC_ACCESS
220 	/*
221 	 * SCR_EL3.TERR: Trap Error record accesses. Accesses to the RAS ERR
222 	 * and RAS ERX registers from EL1 and EL2(from any security state)
223 	 * are trapped to EL3.
224 	 * Set here to trap only for NS EL1/EL2
225 	 *
226 	 */
227 	scr_el3 |= SCR_TERR_BIT;
228 #endif
229 
230 #if ENABLE_FEAT_CSV2_2
231 	/* Enable access to the SCXTNUM_ELx registers. */
232 	scr_el3 |= SCR_EnSCXT_BIT;
233 #endif
234 
235 #ifdef IMAGE_BL31
236 	/*
237 	 * SCR_EL3.IRQ, SCR_EL3.FIQ: Enable the physical FIQ and IRQ routing as
238 	 *  indicated by the interrupt routing model for BL31.
239 	 */
240 	scr_el3 |= get_scr_el3_from_routing_model(NON_SECURE);
241 #endif
242 	write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
243 
244 	/* Initialize EL1 context registers */
245 	setup_el1_context(ctx, ep);
246 
247 	/* Initialize EL2 context registers */
248 #if CTX_INCLUDE_EL2_REGS
249 
250 	/*
251 	 * Initialize SCTLR_EL2 context register using Endianness value
252 	 * taken from the entrypoint attribute.
253 	 */
254 	u_register_t sctlr_el2 = (EP_GET_EE(ep->h.attr) != 0U) ? SCTLR_EE_BIT : 0UL;
255 	sctlr_el2 |= SCTLR_EL2_RES1;
256 	write_ctx_reg(get_el2_sysregs_ctx(ctx), CTX_SCTLR_EL2,
257 			sctlr_el2);
258 
259 	/*
260 	 * Program the ICC_SRE_EL2 to make sure the correct bits are set
261 	 * when restoring NS context.
262 	 */
263 	u_register_t icc_sre_el2 = ICC_SRE_DIB_BIT | ICC_SRE_DFB_BIT |
264 				   ICC_SRE_EN_BIT | ICC_SRE_SRE_BIT;
265 	write_ctx_reg(get_el2_sysregs_ctx(ctx), CTX_ICC_SRE_EL2,
266 			icc_sre_el2);
267 
268 	/*
269 	 * Initialize MDCR_EL2.HPMN to its hardware reset value so we don't
270 	 * throw anyone off who expects this to be sensible.
271 	 * TODO: A similar thing happens in cm_prepare_el3_exit. They should be
272 	 * unified with the proper PMU implementation
273 	 */
274 	u_register_t mdcr_el2 = ((read_pmcr_el0() >> PMCR_EL0_N_SHIFT) &
275 			PMCR_EL0_N_MASK);
276 	write_ctx_reg(get_el2_sysregs_ctx(ctx), CTX_MDCR_EL2, mdcr_el2);
277 #endif /* CTX_INCLUDE_EL2_REGS */
278 }
279 
280 /*******************************************************************************
281  * The following function performs initialization of the cpu_context 'ctx'
282  * for first use that is common to all security states, and sets the
283  * initial entrypoint state as specified by the entry_point_info structure.
284  *
285  * The EE and ST attributes are used to configure the endianness and secure
286  * timer availability for the new execution context.
287  ******************************************************************************/
288 static void setup_context_common(cpu_context_t *ctx, const entry_point_info_t *ep)
289 {
290 	u_register_t scr_el3;
291 	el3_state_t *state;
292 	gp_regs_t *gp_regs;
293 
294 	/* Clear any residual register values from the context */
295 	zeromem(ctx, sizeof(*ctx));
296 
297 	/*
298 	 * SCR_EL3 was initialised during reset sequence in macro
299 	 * el3_arch_init_common. This code modifies the SCR_EL3 fields that
300 	 * affect the next EL.
301 	 *
302 	 * The following fields are initially set to zero and then updated to
303 	 * the required value depending on the state of the SPSR_EL3 and the
304 	 * Security state and entrypoint attributes of the next EL.
305 	 */
306 	scr_el3 = read_scr();
307 	scr_el3 &= ~(SCR_NS_BIT | SCR_RW_BIT | SCR_EA_BIT | SCR_FIQ_BIT | SCR_IRQ_BIT |
308 			SCR_ST_BIT | SCR_HCE_BIT | SCR_NSE_BIT);
309 
310 	/*
311 	 * SCR_EL3.RW: Set the execution state, AArch32 or AArch64, for next
312 	 *  Exception level as specified by SPSR.
313 	 */
314 	if (GET_RW(ep->spsr) == MODE_RW_64) {
315 		scr_el3 |= SCR_RW_BIT;
316 	}
317 
318 	/*
319 	 * SCR_EL3.ST: Traps Secure EL1 accesses to the Counter-timer Physical
320 	 * Secure timer registers to EL3, from AArch64 state only, if specified
321 	 * by the entrypoint attributes. If SEL2 is present and enabled, the ST
322 	 * bit always behaves as 1 (i.e. secure physical timer register access
323 	 * is not trapped)
324 	 */
325 	if (EP_GET_ST(ep->h.attr) != 0U) {
326 		scr_el3 |= SCR_ST_BIT;
327 	}
328 
329 	/*
330 	 * If FEAT_HCX is enabled, enable access to HCRX_EL2 by setting
331 	 * SCR_EL3.HXEn.
332 	 */
333 	if (is_feat_hcx_supported()) {
334 		scr_el3 |= SCR_HXEn_BIT;
335 	}
336 
337 	/*
338 	 * If FEAT_RNG_TRAP is enabled, all reads of the RNDR and RNDRRS
339 	 * registers are trapped to EL3.
340 	 */
341 #if ENABLE_FEAT_RNG_TRAP
342 	scr_el3 |= SCR_TRNDR_BIT;
343 #endif
344 
345 #if FAULT_INJECTION_SUPPORT
346 	/* Enable fault injection from lower ELs */
347 	scr_el3 |= SCR_FIEN_BIT;
348 #endif
349 
350 	/*
351 	 * SCR_EL3.TCR2EN: Enable access to TCR2_ELx for AArch64 if present.
352 	 */
353 	if (is_feat_tcr2_supported() && (GET_RW(ep->spsr) == MODE_RW_64)) {
354 		scr_el3 |= SCR_TCR2EN_BIT;
355 	}
356 
357 	/*
358 	 * CPTR_EL3 was initialized out of reset, copy that value to the
359 	 * context register.
360 	 */
361 	write_ctx_reg(get_el3state_ctx(ctx), CTX_CPTR_EL3, read_cptr_el3());
362 
363 	/*
364 	 * SCR_EL3.HCE: Enable HVC instructions if next execution state is
365 	 * AArch64 and next EL is EL2, or if next execution state is AArch32 and
366 	 * next mode is Hyp.
367 	 * SCR_EL3.FGTEn: Enable Fine Grained Virtualization Traps under the
368 	 * same conditions as HVC instructions and when the processor supports
369 	 * ARMv8.6-FGT.
370 	 * SCR_EL3.ECVEn: Enable Enhanced Counter Virtualization (ECV)
371 	 * CNTPOFF_EL2 register under the same conditions as HVC instructions
372 	 * and when the processor supports ECV.
373 	 */
374 	if (((GET_RW(ep->spsr) == MODE_RW_64) && (GET_EL(ep->spsr) == MODE_EL2))
375 	    || ((GET_RW(ep->spsr) != MODE_RW_64)
376 		&& (GET_M32(ep->spsr) == MODE32_hyp))) {
377 		scr_el3 |= SCR_HCE_BIT;
378 
379 		if (is_feat_fgt_supported()) {
380 			scr_el3 |= SCR_FGTEN_BIT;
381 		}
382 
383 		if (get_armv8_6_ecv_support()
384 		    == ID_AA64MMFR0_EL1_ECV_SELF_SYNCH) {
385 			scr_el3 |= SCR_ECVEN_BIT;
386 		}
387 	}
388 
389 #if ENABLE_FEAT_TWED
390 	/* Enable WFE trap delay in SCR_EL3 if supported and configured */
391 	/* Set delay in SCR_EL3 */
392 	scr_el3 &= ~(SCR_TWEDEL_MASK << SCR_TWEDEL_SHIFT);
393 	scr_el3 |= ((TWED_DELAY & SCR_TWEDEL_MASK)
394 			<< SCR_TWEDEL_SHIFT);
395 
396 	/* Enable WFE delay */
397 	scr_el3 |= SCR_TWEDEn_BIT;
398 #endif /* ENABLE_FEAT_TWED */
399 
400 	/*
401 	 * Populate EL3 state so that we've the right context
402 	 * before doing ERET
403 	 */
404 	state = get_el3state_ctx(ctx);
405 	write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
406 	write_ctx_reg(state, CTX_ELR_EL3, ep->pc);
407 	write_ctx_reg(state, CTX_SPSR_EL3, ep->spsr);
408 
409 	/*
410 	 * Store the X0-X7 value from the entrypoint into the context
411 	 * Use memcpy as we are in control of the layout of the structures
412 	 */
413 	gp_regs = get_gpregs_ctx(ctx);
414 	memcpy(gp_regs, (void *)&ep->args, sizeof(aapcs64_params_t));
415 }
416 
417 /*******************************************************************************
418  * Context management library initialization routine. This library is used by
419  * runtime services to share pointers to 'cpu_context' structures for secure
420  * non-secure and realm states. Management of the structures and their associated
421  * memory is not done by the context management library e.g. the PSCI service
422  * manages the cpu context used for entry from and exit to the non-secure state.
423  * The Secure payload dispatcher service manages the context(s) corresponding to
424  * the secure state. It also uses this library to get access to the non-secure
425  * state cpu context pointers.
426  * Lastly, this library provides the API to make SP_EL3 point to the cpu context
427  * which will be used for programming an entry into a lower EL. The same context
428  * will be used to save state upon exception entry from that EL.
429  ******************************************************************************/
430 void __init cm_init(void)
431 {
432 	/*
433 	 * The context management library has only global data to intialize, but
434 	 * that will be done when the BSS is zeroed out.
435 	 */
436 }
437 
438 /*******************************************************************************
439  * This is the high-level function used to initialize the cpu_context 'ctx' for
440  * first use. It performs initializations that are common to all security states
441  * and initializations specific to the security state specified in 'ep'
442  ******************************************************************************/
443 void cm_setup_context(cpu_context_t *ctx, const entry_point_info_t *ep)
444 {
445 	unsigned int security_state;
446 
447 	assert(ctx != NULL);
448 
449 	/*
450 	 * Perform initializations that are common
451 	 * to all security states
452 	 */
453 	setup_context_common(ctx, ep);
454 
455 	security_state = GET_SECURITY_STATE(ep->h.attr);
456 
457 	/* Perform security state specific initializations */
458 	switch (security_state) {
459 	case SECURE:
460 		setup_secure_context(ctx, ep);
461 		break;
462 #if ENABLE_RME
463 	case REALM:
464 		setup_realm_context(ctx, ep);
465 		break;
466 #endif
467 	case NON_SECURE:
468 		setup_ns_context(ctx, ep);
469 		break;
470 	default:
471 		ERROR("Invalid security state\n");
472 		panic();
473 		break;
474 	}
475 }
476 
477 /*******************************************************************************
478  * Enable architecture extensions on first entry to Non-secure world.
479  * When EL2 is implemented but unused `el2_unused` is non-zero, otherwise
480  * it is zero.
481  ******************************************************************************/
482 static void manage_extensions_nonsecure(bool el2_unused, cpu_context_t *ctx)
483 {
484 #if IMAGE_BL31
485 	if (is_feat_spe_supported()) {
486 		spe_enable(el2_unused);
487 	}
488 
489 #if ENABLE_AMU
490 	amu_enable(el2_unused, ctx);
491 #endif
492 
493 #if ENABLE_SME_FOR_NS
494 	/* Enable SME, SVE, and FPU/SIMD for non-secure world. */
495 	sme_enable(ctx);
496 #elif ENABLE_SVE_FOR_NS
497 	/* Enable SVE and FPU/SIMD for non-secure world. */
498 	sve_enable(ctx);
499 #endif
500 
501 #if ENABLE_MPAM_FOR_LOWER_ELS
502 	mpam_enable(el2_unused);
503 #endif
504 
505 	if (is_feat_trbe_supported()) {
506 		trbe_enable();
507 	}
508 
509 	if (is_feat_brbe_supported()) {
510 		brbe_enable();
511 	}
512 
513 #if ENABLE_SYS_REG_TRACE_FOR_NS
514 	sys_reg_trace_enable(ctx);
515 #endif /* ENABLE_SYS_REG_TRACE_FOR_NS */
516 
517 	if (is_feat_trf_supported()) {
518 		trf_enable();
519 	}
520 #endif
521 }
522 
523 /*******************************************************************************
524  * Enable architecture extensions on first entry to Secure world.
525  ******************************************************************************/
526 static void manage_extensions_secure(cpu_context_t *ctx)
527 {
528 #if IMAGE_BL31
529  #if ENABLE_SME_FOR_NS
530   #if ENABLE_SME_FOR_SWD
531 	/*
532 	 * Enable SME, SVE, FPU/SIMD in secure context, secure manager must
533 	 * ensure SME, SVE, and FPU/SIMD context properly managed.
534 	 */
535 	sme_enable(ctx);
536   #else /* ENABLE_SME_FOR_SWD */
537 	/*
538 	 * Disable SME, SVE, FPU/SIMD in secure context so non-secure world can
539 	 * safely use the associated registers.
540 	 */
541 	sme_disable(ctx);
542   #endif /* ENABLE_SME_FOR_SWD */
543  #elif ENABLE_SVE_FOR_NS
544   #if ENABLE_SVE_FOR_SWD
545 	/*
546 	 * Enable SVE and FPU in secure context, secure manager must ensure that
547 	 * the SVE and FPU register contexts are properly managed.
548 	 */
549 	sve_enable(ctx);
550  #else /* ENABLE_SVE_FOR_SWD */
551 	/*
552 	 * Disable SVE and FPU in secure context so non-secure world can safely
553 	 * use them.
554 	 */
555 	sve_disable(ctx);
556   #endif /* ENABLE_SVE_FOR_SWD */
557  #endif /* ENABLE_SVE_FOR_NS */
558 #endif /* IMAGE_BL31 */
559 }
560 
561 /*******************************************************************************
562  * The following function initializes the cpu_context for a CPU specified by
563  * its `cpu_idx` for first use, and sets the initial entrypoint state as
564  * specified by the entry_point_info structure.
565  ******************************************************************************/
566 void cm_init_context_by_index(unsigned int cpu_idx,
567 			      const entry_point_info_t *ep)
568 {
569 	cpu_context_t *ctx;
570 	ctx = cm_get_context_by_index(cpu_idx, GET_SECURITY_STATE(ep->h.attr));
571 	cm_setup_context(ctx, ep);
572 }
573 
574 /*******************************************************************************
575  * The following function initializes the cpu_context for the current CPU
576  * for first use, and sets the initial entrypoint state as specified by the
577  * entry_point_info structure.
578  ******************************************************************************/
579 void cm_init_my_context(const entry_point_info_t *ep)
580 {
581 	cpu_context_t *ctx;
582 	ctx = cm_get_context(GET_SECURITY_STATE(ep->h.attr));
583 	cm_setup_context(ctx, ep);
584 }
585 
586 /*******************************************************************************
587  * Prepare the CPU system registers for first entry into realm, secure, or
588  * normal world.
589  *
590  * If execution is requested to EL2 or hyp mode, SCTLR_EL2 is initialized
591  * If execution is requested to non-secure EL1 or svc mode, and the CPU supports
592  * EL2 then EL2 is disabled by configuring all necessary EL2 registers.
593  * For all entries, the EL1 registers are initialized from the cpu_context
594  ******************************************************************************/
595 void cm_prepare_el3_exit(uint32_t security_state)
596 {
597 	u_register_t sctlr_elx, scr_el3, mdcr_el2;
598 	cpu_context_t *ctx = cm_get_context(security_state);
599 	bool el2_unused = false;
600 	uint64_t hcr_el2 = 0U;
601 
602 	assert(ctx != NULL);
603 
604 	if (security_state == NON_SECURE) {
605 		scr_el3 = read_ctx_reg(get_el3state_ctx(ctx),
606 						 CTX_SCR_EL3);
607 		if ((scr_el3 & SCR_HCE_BIT) != 0U) {
608 			/* Use SCTLR_EL1.EE value to initialise sctlr_el2 */
609 			sctlr_elx = read_ctx_reg(get_el1_sysregs_ctx(ctx),
610 							   CTX_SCTLR_EL1);
611 			sctlr_elx &= SCTLR_EE_BIT;
612 			sctlr_elx |= SCTLR_EL2_RES1;
613 #if ERRATA_A75_764081
614 			/*
615 			 * If workaround of errata 764081 for Cortex-A75 is used
616 			 * then set SCTLR_EL2.IESB to enable Implicit Error
617 			 * Synchronization Barrier.
618 			 */
619 			sctlr_elx |= SCTLR_IESB_BIT;
620 #endif
621 			write_sctlr_el2(sctlr_elx);
622 		} else if (el_implemented(2) != EL_IMPL_NONE) {
623 			el2_unused = true;
624 
625 			/*
626 			 * EL2 present but unused, need to disable safely.
627 			 * SCTLR_EL2 can be ignored in this case.
628 			 *
629 			 * Set EL2 register width appropriately: Set HCR_EL2
630 			 * field to match SCR_EL3.RW.
631 			 */
632 			if ((scr_el3 & SCR_RW_BIT) != 0U)
633 				hcr_el2 |= HCR_RW_BIT;
634 
635 			/*
636 			 * For Armv8.3 pointer authentication feature, disable
637 			 * traps to EL2 when accessing key registers or using
638 			 * pointer authentication instructions from lower ELs.
639 			 */
640 			hcr_el2 |= (HCR_API_BIT | HCR_APK_BIT);
641 
642 			write_hcr_el2(hcr_el2);
643 
644 			/*
645 			 * Initialise CPTR_EL2 setting all fields rather than
646 			 * relying on the hw. All fields have architecturally
647 			 * UNKNOWN reset values.
648 			 *
649 			 * CPTR_EL2.TCPAC: Set to zero so that Non-secure EL1
650 			 *  accesses to the CPACR_EL1 or CPACR from both
651 			 *  Execution states do not trap to EL2.
652 			 *
653 			 * CPTR_EL2.TTA: Set to zero so that Non-secure System
654 			 *  register accesses to the trace registers from both
655 			 *  Execution states do not trap to EL2.
656 			 *  If PE trace unit System registers are not implemented
657 			 *  then this bit is reserved, and must be set to zero.
658 			 *
659 			 * CPTR_EL2.TFP: Set to zero so that Non-secure accesses
660 			 *  to SIMD and floating-point functionality from both
661 			 *  Execution states do not trap to EL2.
662 			 */
663 			write_cptr_el2(CPTR_EL2_RESET_VAL &
664 					~(CPTR_EL2_TCPAC_BIT | CPTR_EL2_TTA_BIT
665 					| CPTR_EL2_TFP_BIT));
666 
667 			/*
668 			 * Initialise CNTHCTL_EL2. All fields are
669 			 * architecturally UNKNOWN on reset and are set to zero
670 			 * except for field(s) listed below.
671 			 *
672 			 * CNTHCTL_EL2.EL1PTEN: Set to one to disable traps to
673 			 *  Hyp mode of Non-secure EL0 and EL1 accesses to the
674 			 *  physical timer registers.
675 			 *
676 			 * CNTHCTL_EL2.EL1PCTEN: Set to one to disable traps to
677 			 *  Hyp mode of  Non-secure EL0 and EL1 accesses to the
678 			 *  physical counter registers.
679 			 */
680 			write_cnthctl_el2(CNTHCTL_RESET_VAL |
681 						EL1PCEN_BIT | EL1PCTEN_BIT);
682 
683 			/*
684 			 * Initialise CNTVOFF_EL2 to zero as it resets to an
685 			 * architecturally UNKNOWN value.
686 			 */
687 			write_cntvoff_el2(0);
688 
689 			/*
690 			 * Set VPIDR_EL2 and VMPIDR_EL2 to match MIDR_EL1 and
691 			 * MPIDR_EL1 respectively.
692 			 */
693 			write_vpidr_el2(read_midr_el1());
694 			write_vmpidr_el2(read_mpidr_el1());
695 
696 			/*
697 			 * Initialise VTTBR_EL2. All fields are architecturally
698 			 * UNKNOWN on reset.
699 			 *
700 			 * VTTBR_EL2.VMID: Set to zero. Even though EL1&0 stage
701 			 *  2 address translation is disabled, cache maintenance
702 			 *  operations depend on the VMID.
703 			 *
704 			 * VTTBR_EL2.BADDR: Set to zero as EL1&0 stage 2 address
705 			 *  translation is disabled.
706 			 */
707 			write_vttbr_el2(VTTBR_RESET_VAL &
708 				~((VTTBR_VMID_MASK << VTTBR_VMID_SHIFT)
709 				| (VTTBR_BADDR_MASK << VTTBR_BADDR_SHIFT)));
710 
711 			/*
712 			 * Initialise MDCR_EL2, setting all fields rather than
713 			 * relying on hw. Some fields are architecturally
714 			 * UNKNOWN on reset.
715 			 *
716 			 * MDCR_EL2.HLP: Set to one so that event counter
717 			 *  overflow, that is recorded in PMOVSCLR_EL0[0-30],
718 			 *  occurs on the increment that changes
719 			 *  PMEVCNTR<n>_EL0[63] from 1 to 0, when ARMv8.5-PMU is
720 			 *  implemented. This bit is RES0 in versions of the
721 			 *  architecture earlier than ARMv8.5, setting it to 1
722 			 *  doesn't have any effect on them.
723 			 *
724 			 * MDCR_EL2.TTRF: Set to zero so that access to Trace
725 			 *  Filter Control register TRFCR_EL1 at EL1 is not
726 			 *  trapped to EL2. This bit is RES0 in versions of
727 			 *  the architecture earlier than ARMv8.4.
728 			 *
729 			 * MDCR_EL2.HPMD: Set to one so that event counting is
730 			 *  prohibited at EL2. This bit is RES0 in versions of
731 			 *  the architecture earlier than ARMv8.1, setting it
732 			 *  to 1 doesn't have any effect on them.
733 			 *
734 			 * MDCR_EL2.TPMS: Set to zero so that accesses to
735 			 *  Statistical Profiling control registers from EL1
736 			 *  do not trap to EL2. This bit is RES0 when SPE is
737 			 *  not implemented.
738 			 *
739 			 * MDCR_EL2.TDRA: Set to zero so that Non-secure EL0 and
740 			 *  EL1 System register accesses to the Debug ROM
741 			 *  registers are not trapped to EL2.
742 			 *
743 			 * MDCR_EL2.TDOSA: Set to zero so that Non-secure EL1
744 			 *  System register accesses to the powerdown debug
745 			 *  registers are not trapped to EL2.
746 			 *
747 			 * MDCR_EL2.TDA: Set to zero so that System register
748 			 *  accesses to the debug registers do not trap to EL2.
749 			 *
750 			 * MDCR_EL2.TDE: Set to zero so that debug exceptions
751 			 *  are not routed to EL2.
752 			 *
753 			 * MDCR_EL2.HPME: Set to zero to disable EL2 Performance
754 			 *  Monitors.
755 			 *
756 			 * MDCR_EL2.TPM: Set to zero so that Non-secure EL0 and
757 			 *  EL1 accesses to all Performance Monitors registers
758 			 *  are not trapped to EL2.
759 			 *
760 			 * MDCR_EL2.TPMCR: Set to zero so that Non-secure EL0
761 			 *  and EL1 accesses to the PMCR_EL0 or PMCR are not
762 			 *  trapped to EL2.
763 			 *
764 			 * MDCR_EL2.HPMN: Set to value of PMCR_EL0.N which is the
765 			 *  architecturally-defined reset value.
766 			 *
767 			 * MDCR_EL2.E2TB: Set to zero so that the trace Buffer
768 			 *  owning exception level is NS-EL1 and, tracing is
769 			 *  prohibited at NS-EL2. These bits are RES0 when
770 			 *  FEAT_TRBE is not implemented.
771 			 */
772 			mdcr_el2 = ((MDCR_EL2_RESET_VAL | MDCR_EL2_HLP |
773 				     MDCR_EL2_HPMD) |
774 				   ((read_pmcr_el0() & PMCR_EL0_N_BITS)
775 				   >> PMCR_EL0_N_SHIFT)) &
776 				   ~(MDCR_EL2_TTRF | MDCR_EL2_TPMS |
777 				     MDCR_EL2_TDRA_BIT | MDCR_EL2_TDOSA_BIT |
778 				     MDCR_EL2_TDA_BIT | MDCR_EL2_TDE_BIT |
779 				     MDCR_EL2_HPME_BIT | MDCR_EL2_TPM_BIT |
780 				     MDCR_EL2_TPMCR_BIT |
781 				     MDCR_EL2_E2TB(MDCR_EL2_E2TB_EL1));
782 
783 			write_mdcr_el2(mdcr_el2);
784 
785 			/*
786 			 * Initialise HSTR_EL2. All fields are architecturally
787 			 * UNKNOWN on reset.
788 			 *
789 			 * HSTR_EL2.T<n>: Set all these fields to zero so that
790 			 *  Non-secure EL0 or EL1 accesses to System registers
791 			 *  do not trap to EL2.
792 			 */
793 			write_hstr_el2(HSTR_EL2_RESET_VAL & ~(HSTR_EL2_T_MASK));
794 			/*
795 			 * Initialise CNTHP_CTL_EL2. All fields are
796 			 * architecturally UNKNOWN on reset.
797 			 *
798 			 * CNTHP_CTL_EL2:ENABLE: Set to zero to disable the EL2
799 			 *  physical timer and prevent timer interrupts.
800 			 */
801 			write_cnthp_ctl_el2(CNTHP_CTL_RESET_VAL &
802 						~(CNTHP_CTL_ENABLE_BIT));
803 		}
804 		manage_extensions_nonsecure(el2_unused, ctx);
805 	}
806 
807 	cm_el1_sysregs_context_restore(security_state);
808 	cm_set_next_eret_context(security_state);
809 }
810 
811 #if CTX_INCLUDE_EL2_REGS
812 
813 static void el2_sysregs_context_save_fgt(el2_sysregs_t *ctx)
814 {
815 	write_ctx_reg(ctx, CTX_HDFGRTR_EL2, read_hdfgrtr_el2());
816 	if (is_feat_amu_supported()) {
817 		write_ctx_reg(ctx, CTX_HAFGRTR_EL2, read_hafgrtr_el2());
818 	}
819 	write_ctx_reg(ctx, CTX_HDFGWTR_EL2, read_hdfgwtr_el2());
820 	write_ctx_reg(ctx, CTX_HFGITR_EL2, read_hfgitr_el2());
821 	write_ctx_reg(ctx, CTX_HFGRTR_EL2, read_hfgrtr_el2());
822 	write_ctx_reg(ctx, CTX_HFGWTR_EL2, read_hfgwtr_el2());
823 }
824 
825 static void el2_sysregs_context_restore_fgt(el2_sysregs_t *ctx)
826 {
827 	write_hdfgrtr_el2(read_ctx_reg(ctx, CTX_HDFGRTR_EL2));
828 	if (is_feat_amu_supported()) {
829 		write_hafgrtr_el2(read_ctx_reg(ctx, CTX_HAFGRTR_EL2));
830 	}
831 	write_hdfgwtr_el2(read_ctx_reg(ctx, CTX_HDFGWTR_EL2));
832 	write_hfgitr_el2(read_ctx_reg(ctx, CTX_HFGITR_EL2));
833 	write_hfgrtr_el2(read_ctx_reg(ctx, CTX_HFGRTR_EL2));
834 	write_hfgwtr_el2(read_ctx_reg(ctx, CTX_HFGWTR_EL2));
835 }
836 
837 /*******************************************************************************
838  * Save EL2 sysreg context
839  ******************************************************************************/
840 void cm_el2_sysregs_context_save(uint32_t security_state)
841 {
842 	u_register_t scr_el3 = read_scr();
843 
844 	/*
845 	 * Always save the non-secure and realm EL2 context, only save the
846 	 * S-EL2 context if S-EL2 is enabled.
847 	 */
848 	if ((security_state != SECURE) ||
849 	    ((security_state == SECURE) && ((scr_el3 & SCR_EEL2_BIT) != 0U))) {
850 		cpu_context_t *ctx;
851 		el2_sysregs_t *el2_sysregs_ctx;
852 
853 		ctx = cm_get_context(security_state);
854 		assert(ctx != NULL);
855 
856 		el2_sysregs_ctx = get_el2_sysregs_ctx(ctx);
857 
858 		el2_sysregs_context_save_common(el2_sysregs_ctx);
859 #if CTX_INCLUDE_MTE_REGS
860 		el2_sysregs_context_save_mte(el2_sysregs_ctx);
861 #endif
862 #if ENABLE_MPAM_FOR_LOWER_ELS
863 		el2_sysregs_context_save_mpam(el2_sysregs_ctx);
864 #endif
865 
866 		if (is_feat_fgt_supported()) {
867 			el2_sysregs_context_save_fgt(el2_sysregs_ctx);
868 		}
869 
870 #if ENABLE_FEAT_ECV
871 		el2_sysregs_context_save_ecv(el2_sysregs_ctx);
872 #endif
873 #if ENABLE_FEAT_VHE
874 		el2_sysregs_context_save_vhe(el2_sysregs_ctx);
875 #endif
876 #if RAS_EXTENSION
877 		el2_sysregs_context_save_ras(el2_sysregs_ctx);
878 #endif
879 #if CTX_INCLUDE_NEVE_REGS
880 		el2_sysregs_context_save_nv2(el2_sysregs_ctx);
881 #endif
882 		if (is_feat_trf_supported()) {
883 			write_ctx_reg(el2_sysregs_ctx, CTX_TRFCR_EL2, read_trfcr_el2());
884 		}
885 #if ENABLE_FEAT_CSV2_2
886 		el2_sysregs_context_save_csv2(el2_sysregs_ctx);
887 #endif
888 		if (is_feat_hcx_supported()) {
889 			write_ctx_reg(el2_sysregs_ctx, CTX_HCRX_EL2, read_hcrx_el2());
890 		}
891 		if (is_feat_tcr2_supported()) {
892 			write_ctx_reg(el2_sysregs_ctx, CTX_TCR2_EL2, read_tcr2_el2());
893 		}
894 	}
895 }
896 
897 /*******************************************************************************
898  * Restore EL2 sysreg context
899  ******************************************************************************/
900 void cm_el2_sysregs_context_restore(uint32_t security_state)
901 {
902 	u_register_t scr_el3 = read_scr();
903 
904 	/*
905 	 * Always restore the non-secure and realm EL2 context, only restore the
906 	 * S-EL2 context if S-EL2 is enabled.
907 	 */
908 	if ((security_state != SECURE) ||
909 	    ((security_state == SECURE) && ((scr_el3 & SCR_EEL2_BIT) != 0U))) {
910 		cpu_context_t *ctx;
911 		el2_sysregs_t *el2_sysregs_ctx;
912 
913 		ctx = cm_get_context(security_state);
914 		assert(ctx != NULL);
915 
916 		el2_sysregs_ctx = get_el2_sysregs_ctx(ctx);
917 
918 		el2_sysregs_context_restore_common(el2_sysregs_ctx);
919 #if CTX_INCLUDE_MTE_REGS
920 		el2_sysregs_context_restore_mte(el2_sysregs_ctx);
921 #endif
922 #if ENABLE_MPAM_FOR_LOWER_ELS
923 		el2_sysregs_context_restore_mpam(el2_sysregs_ctx);
924 #endif
925 
926 		if (is_feat_fgt_supported()) {
927 			el2_sysregs_context_restore_fgt(el2_sysregs_ctx);
928 		}
929 
930 #if ENABLE_FEAT_ECV
931 		el2_sysregs_context_restore_ecv(el2_sysregs_ctx);
932 #endif
933 #if ENABLE_FEAT_VHE
934 		el2_sysregs_context_restore_vhe(el2_sysregs_ctx);
935 #endif
936 #if RAS_EXTENSION
937 		el2_sysregs_context_restore_ras(el2_sysregs_ctx);
938 #endif
939 #if CTX_INCLUDE_NEVE_REGS
940 		el2_sysregs_context_restore_nv2(el2_sysregs_ctx);
941 #endif
942 		if (is_feat_trf_supported()) {
943 			write_trfcr_el2(read_ctx_reg(el2_sysregs_ctx, CTX_TRFCR_EL2));
944 		}
945 #if ENABLE_FEAT_CSV2_2
946 		el2_sysregs_context_restore_csv2(el2_sysregs_ctx);
947 #endif
948 		if (is_feat_hcx_supported()) {
949 			write_hcrx_el2(read_ctx_reg(el2_sysregs_ctx, CTX_HCRX_EL2));
950 		}
951 		if (is_feat_tcr2_supported()) {
952 			write_tcr2_el2(read_ctx_reg(el2_sysregs_ctx, CTX_TCR2_EL2));
953 		}
954 	}
955 }
956 #endif /* CTX_INCLUDE_EL2_REGS */
957 
958 /*******************************************************************************
959  * This function is used to exit to Non-secure world. If CTX_INCLUDE_EL2_REGS
960  * is enabled, it restores EL1 and EL2 sysreg contexts instead of directly
961  * updating EL1 and EL2 registers. Otherwise, it calls the generic
962  * cm_prepare_el3_exit function.
963  ******************************************************************************/
964 void cm_prepare_el3_exit_ns(void)
965 {
966 #if CTX_INCLUDE_EL2_REGS
967 	cpu_context_t *ctx = cm_get_context(NON_SECURE);
968 	assert(ctx != NULL);
969 
970 	/* Assert that EL2 is used. */
971 #if ENABLE_ASSERTIONS
972 	el3_state_t *state = get_el3state_ctx(ctx);
973 	u_register_t scr_el3 = read_ctx_reg(state, CTX_SCR_EL3);
974 #endif
975 	assert(((scr_el3 & SCR_HCE_BIT) != 0UL) &&
976 			(el_implemented(2U) != EL_IMPL_NONE));
977 
978 	/*
979 	 * Currently some extensions are configured using
980 	 * direct register updates. Therefore, do this here
981 	 * instead of when setting up context.
982 	 */
983 	manage_extensions_nonsecure(0, ctx);
984 
985 	/*
986 	 * Set the NS bit to be able to access the ICC_SRE_EL2
987 	 * register when restoring context.
988 	 */
989 	write_scr_el3(read_scr_el3() | SCR_NS_BIT);
990 
991 	/*
992 	 * Ensure the NS bit change is committed before the EL2/EL1
993 	 * state restoration.
994 	 */
995 	isb();
996 
997 	/* Restore EL2 and EL1 sysreg contexts */
998 	cm_el2_sysregs_context_restore(NON_SECURE);
999 	cm_el1_sysregs_context_restore(NON_SECURE);
1000 	cm_set_next_eret_context(NON_SECURE);
1001 #else
1002 	cm_prepare_el3_exit(NON_SECURE);
1003 #endif /* CTX_INCLUDE_EL2_REGS */
1004 }
1005 
1006 /*******************************************************************************
1007  * The next four functions are used by runtime services to save and restore
1008  * EL1 context on the 'cpu_context' structure for the specified security
1009  * state.
1010  ******************************************************************************/
1011 void cm_el1_sysregs_context_save(uint32_t security_state)
1012 {
1013 	cpu_context_t *ctx;
1014 
1015 	ctx = cm_get_context(security_state);
1016 	assert(ctx != NULL);
1017 
1018 	el1_sysregs_context_save(get_el1_sysregs_ctx(ctx));
1019 
1020 #if IMAGE_BL31
1021 	if (security_state == SECURE)
1022 		PUBLISH_EVENT(cm_exited_secure_world);
1023 	else
1024 		PUBLISH_EVENT(cm_exited_normal_world);
1025 #endif
1026 }
1027 
1028 void cm_el1_sysregs_context_restore(uint32_t security_state)
1029 {
1030 	cpu_context_t *ctx;
1031 
1032 	ctx = cm_get_context(security_state);
1033 	assert(ctx != NULL);
1034 
1035 	el1_sysregs_context_restore(get_el1_sysregs_ctx(ctx));
1036 
1037 #if IMAGE_BL31
1038 	if (security_state == SECURE)
1039 		PUBLISH_EVENT(cm_entering_secure_world);
1040 	else
1041 		PUBLISH_EVENT(cm_entering_normal_world);
1042 #endif
1043 }
1044 
1045 /*******************************************************************************
1046  * This function populates ELR_EL3 member of 'cpu_context' pertaining to the
1047  * given security state with the given entrypoint
1048  ******************************************************************************/
1049 void cm_set_elr_el3(uint32_t security_state, uintptr_t entrypoint)
1050 {
1051 	cpu_context_t *ctx;
1052 	el3_state_t *state;
1053 
1054 	ctx = cm_get_context(security_state);
1055 	assert(ctx != NULL);
1056 
1057 	/* Populate EL3 state so that ERET jumps to the correct entry */
1058 	state = get_el3state_ctx(ctx);
1059 	write_ctx_reg(state, CTX_ELR_EL3, entrypoint);
1060 }
1061 
1062 /*******************************************************************************
1063  * This function populates ELR_EL3 and SPSR_EL3 members of 'cpu_context'
1064  * pertaining to the given security state
1065  ******************************************************************************/
1066 void cm_set_elr_spsr_el3(uint32_t security_state,
1067 			uintptr_t entrypoint, uint32_t spsr)
1068 {
1069 	cpu_context_t *ctx;
1070 	el3_state_t *state;
1071 
1072 	ctx = cm_get_context(security_state);
1073 	assert(ctx != NULL);
1074 
1075 	/* Populate EL3 state so that ERET jumps to the correct entry */
1076 	state = get_el3state_ctx(ctx);
1077 	write_ctx_reg(state, CTX_ELR_EL3, entrypoint);
1078 	write_ctx_reg(state, CTX_SPSR_EL3, spsr);
1079 }
1080 
1081 /*******************************************************************************
1082  * This function updates a single bit in the SCR_EL3 member of the 'cpu_context'
1083  * pertaining to the given security state using the value and bit position
1084  * specified in the parameters. It preserves all other bits.
1085  ******************************************************************************/
1086 void cm_write_scr_el3_bit(uint32_t security_state,
1087 			  uint32_t bit_pos,
1088 			  uint32_t value)
1089 {
1090 	cpu_context_t *ctx;
1091 	el3_state_t *state;
1092 	u_register_t scr_el3;
1093 
1094 	ctx = cm_get_context(security_state);
1095 	assert(ctx != NULL);
1096 
1097 	/* Ensure that the bit position is a valid one */
1098 	assert(((1UL << bit_pos) & SCR_VALID_BIT_MASK) != 0U);
1099 
1100 	/* Ensure that the 'value' is only a bit wide */
1101 	assert(value <= 1U);
1102 
1103 	/*
1104 	 * Get the SCR_EL3 value from the cpu context, clear the desired bit
1105 	 * and set it to its new value.
1106 	 */
1107 	state = get_el3state_ctx(ctx);
1108 	scr_el3 = read_ctx_reg(state, CTX_SCR_EL3);
1109 	scr_el3 &= ~(1UL << bit_pos);
1110 	scr_el3 |= (u_register_t)value << bit_pos;
1111 	write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
1112 }
1113 
1114 /*******************************************************************************
1115  * This function retrieves SCR_EL3 member of 'cpu_context' pertaining to the
1116  * given security state.
1117  ******************************************************************************/
1118 u_register_t cm_get_scr_el3(uint32_t security_state)
1119 {
1120 	cpu_context_t *ctx;
1121 	el3_state_t *state;
1122 
1123 	ctx = cm_get_context(security_state);
1124 	assert(ctx != NULL);
1125 
1126 	/* Populate EL3 state so that ERET jumps to the correct entry */
1127 	state = get_el3state_ctx(ctx);
1128 	return read_ctx_reg(state, CTX_SCR_EL3);
1129 }
1130 
1131 /*******************************************************************************
1132  * This function is used to program the context that's used for exception
1133  * return. This initializes the SP_EL3 to a pointer to a 'cpu_context' set for
1134  * the required security state
1135  ******************************************************************************/
1136 void cm_set_next_eret_context(uint32_t security_state)
1137 {
1138 	cpu_context_t *ctx;
1139 
1140 	ctx = cm_get_context(security_state);
1141 	assert(ctx != NULL);
1142 
1143 	cm_set_next_context(ctx);
1144 }
1145