xref: /rk3399_ARM-atf/lib/el3_runtime/aarch64/context_mgmt.c (revision 6bb49c876c7593ed5f61c20ef3d989dcff8e8d8c)
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 	 * CPTR_EL3 was initialized out of reset, copy that value to the
352 	 * context register.
353 	 */
354 	write_ctx_reg(get_el3state_ctx(ctx), CTX_CPTR_EL3, read_cptr_el3());
355 
356 	/*
357 	 * SCR_EL3.HCE: Enable HVC instructions if next execution state is
358 	 * AArch64 and next EL is EL2, or if next execution state is AArch32 and
359 	 * next mode is Hyp.
360 	 * SCR_EL3.FGTEn: Enable Fine Grained Virtualization Traps under the
361 	 * same conditions as HVC instructions and when the processor supports
362 	 * ARMv8.6-FGT.
363 	 * SCR_EL3.ECVEn: Enable Enhanced Counter Virtualization (ECV)
364 	 * CNTPOFF_EL2 register under the same conditions as HVC instructions
365 	 * and when the processor supports ECV.
366 	 */
367 	if (((GET_RW(ep->spsr) == MODE_RW_64) && (GET_EL(ep->spsr) == MODE_EL2))
368 	    || ((GET_RW(ep->spsr) != MODE_RW_64)
369 		&& (GET_M32(ep->spsr) == MODE32_hyp))) {
370 		scr_el3 |= SCR_HCE_BIT;
371 
372 		if (is_feat_fgt_supported()) {
373 			scr_el3 |= SCR_FGTEN_BIT;
374 		}
375 
376 		if (get_armv8_6_ecv_support()
377 		    == ID_AA64MMFR0_EL1_ECV_SELF_SYNCH) {
378 			scr_el3 |= SCR_ECVEN_BIT;
379 		}
380 	}
381 
382 #if ENABLE_FEAT_TWED
383 	/* Enable WFE trap delay in SCR_EL3 if supported and configured */
384 	/* Set delay in SCR_EL3 */
385 	scr_el3 &= ~(SCR_TWEDEL_MASK << SCR_TWEDEL_SHIFT);
386 	scr_el3 |= ((TWED_DELAY & SCR_TWEDEL_MASK)
387 			<< SCR_TWEDEL_SHIFT);
388 
389 	/* Enable WFE delay */
390 	scr_el3 |= SCR_TWEDEn_BIT;
391 #endif /* ENABLE_FEAT_TWED */
392 
393 	/*
394 	 * Populate EL3 state so that we've the right context
395 	 * before doing ERET
396 	 */
397 	state = get_el3state_ctx(ctx);
398 	write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
399 	write_ctx_reg(state, CTX_ELR_EL3, ep->pc);
400 	write_ctx_reg(state, CTX_SPSR_EL3, ep->spsr);
401 
402 	/*
403 	 * Store the X0-X7 value from the entrypoint into the context
404 	 * Use memcpy as we are in control of the layout of the structures
405 	 */
406 	gp_regs = get_gpregs_ctx(ctx);
407 	memcpy(gp_regs, (void *)&ep->args, sizeof(aapcs64_params_t));
408 }
409 
410 /*******************************************************************************
411  * Context management library initialization routine. This library is used by
412  * runtime services to share pointers to 'cpu_context' structures for secure
413  * non-secure and realm states. Management of the structures and their associated
414  * memory is not done by the context management library e.g. the PSCI service
415  * manages the cpu context used for entry from and exit to the non-secure state.
416  * The Secure payload dispatcher service manages the context(s) corresponding to
417  * the secure state. It also uses this library to get access to the non-secure
418  * state cpu context pointers.
419  * Lastly, this library provides the API to make SP_EL3 point to the cpu context
420  * which will be used for programming an entry into a lower EL. The same context
421  * will be used to save state upon exception entry from that EL.
422  ******************************************************************************/
423 void __init cm_init(void)
424 {
425 	/*
426 	 * The context management library has only global data to intialize, but
427 	 * that will be done when the BSS is zeroed out.
428 	 */
429 }
430 
431 /*******************************************************************************
432  * This is the high-level function used to initialize the cpu_context 'ctx' for
433  * first use. It performs initializations that are common to all security states
434  * and initializations specific to the security state specified in 'ep'
435  ******************************************************************************/
436 void cm_setup_context(cpu_context_t *ctx, const entry_point_info_t *ep)
437 {
438 	unsigned int security_state;
439 
440 	assert(ctx != NULL);
441 
442 	/*
443 	 * Perform initializations that are common
444 	 * to all security states
445 	 */
446 	setup_context_common(ctx, ep);
447 
448 	security_state = GET_SECURITY_STATE(ep->h.attr);
449 
450 	/* Perform security state specific initializations */
451 	switch (security_state) {
452 	case SECURE:
453 		setup_secure_context(ctx, ep);
454 		break;
455 #if ENABLE_RME
456 	case REALM:
457 		setup_realm_context(ctx, ep);
458 		break;
459 #endif
460 	case NON_SECURE:
461 		setup_ns_context(ctx, ep);
462 		break;
463 	default:
464 		ERROR("Invalid security state\n");
465 		panic();
466 		break;
467 	}
468 }
469 
470 /*******************************************************************************
471  * Enable architecture extensions on first entry to Non-secure world.
472  * When EL2 is implemented but unused `el2_unused` is non-zero, otherwise
473  * it is zero.
474  ******************************************************************************/
475 static void manage_extensions_nonsecure(bool el2_unused, cpu_context_t *ctx)
476 {
477 #if IMAGE_BL31
478 #if ENABLE_SPE_FOR_LOWER_ELS
479 	spe_enable(el2_unused);
480 #endif
481 
482 #if ENABLE_AMU
483 	amu_enable(el2_unused, ctx);
484 #endif
485 
486 #if ENABLE_SME_FOR_NS
487 	/* Enable SME, SVE, and FPU/SIMD for non-secure world. */
488 	sme_enable(ctx);
489 #elif ENABLE_SVE_FOR_NS
490 	/* Enable SVE and FPU/SIMD for non-secure world. */
491 	sve_enable(ctx);
492 #endif
493 
494 #if ENABLE_MPAM_FOR_LOWER_ELS
495 	mpam_enable(el2_unused);
496 #endif
497 
498 	if (is_feat_trbe_supported()) {
499 		trbe_enable();
500 	}
501 
502 	if (is_feat_brbe_supported()) {
503 		brbe_enable();
504 	}
505 
506 #if ENABLE_SYS_REG_TRACE_FOR_NS
507 	sys_reg_trace_enable(ctx);
508 #endif /* ENABLE_SYS_REG_TRACE_FOR_NS */
509 
510 	if (is_feat_trf_supported()) {
511 		trf_enable();
512 	}
513 #endif
514 }
515 
516 /*******************************************************************************
517  * Enable architecture extensions on first entry to Secure world.
518  ******************************************************************************/
519 static void manage_extensions_secure(cpu_context_t *ctx)
520 {
521 #if IMAGE_BL31
522  #if ENABLE_SME_FOR_NS
523   #if ENABLE_SME_FOR_SWD
524 	/*
525 	 * Enable SME, SVE, FPU/SIMD in secure context, secure manager must
526 	 * ensure SME, SVE, and FPU/SIMD context properly managed.
527 	 */
528 	sme_enable(ctx);
529   #else /* ENABLE_SME_FOR_SWD */
530 	/*
531 	 * Disable SME, SVE, FPU/SIMD in secure context so non-secure world can
532 	 * safely use the associated registers.
533 	 */
534 	sme_disable(ctx);
535   #endif /* ENABLE_SME_FOR_SWD */
536  #elif ENABLE_SVE_FOR_NS
537   #if ENABLE_SVE_FOR_SWD
538 	/*
539 	 * Enable SVE and FPU in secure context, secure manager must ensure that
540 	 * the SVE and FPU register contexts are properly managed.
541 	 */
542 	sve_enable(ctx);
543  #else /* ENABLE_SVE_FOR_SWD */
544 	/*
545 	 * Disable SVE and FPU in secure context so non-secure world can safely
546 	 * use them.
547 	 */
548 	sve_disable(ctx);
549   #endif /* ENABLE_SVE_FOR_SWD */
550  #endif /* ENABLE_SVE_FOR_NS */
551 #endif /* IMAGE_BL31 */
552 }
553 
554 /*******************************************************************************
555  * The following function initializes the cpu_context for a CPU specified by
556  * its `cpu_idx` for first use, and sets the initial entrypoint state as
557  * specified by the entry_point_info structure.
558  ******************************************************************************/
559 void cm_init_context_by_index(unsigned int cpu_idx,
560 			      const entry_point_info_t *ep)
561 {
562 	cpu_context_t *ctx;
563 	ctx = cm_get_context_by_index(cpu_idx, GET_SECURITY_STATE(ep->h.attr));
564 	cm_setup_context(ctx, ep);
565 }
566 
567 /*******************************************************************************
568  * The following function initializes the cpu_context for the current CPU
569  * for first use, and sets the initial entrypoint state as specified by the
570  * entry_point_info structure.
571  ******************************************************************************/
572 void cm_init_my_context(const entry_point_info_t *ep)
573 {
574 	cpu_context_t *ctx;
575 	ctx = cm_get_context(GET_SECURITY_STATE(ep->h.attr));
576 	cm_setup_context(ctx, ep);
577 }
578 
579 /*******************************************************************************
580  * Prepare the CPU system registers for first entry into realm, secure, or
581  * normal world.
582  *
583  * If execution is requested to EL2 or hyp mode, SCTLR_EL2 is initialized
584  * If execution is requested to non-secure EL1 or svc mode, and the CPU supports
585  * EL2 then EL2 is disabled by configuring all necessary EL2 registers.
586  * For all entries, the EL1 registers are initialized from the cpu_context
587  ******************************************************************************/
588 void cm_prepare_el3_exit(uint32_t security_state)
589 {
590 	u_register_t sctlr_elx, scr_el3, mdcr_el2;
591 	cpu_context_t *ctx = cm_get_context(security_state);
592 	bool el2_unused = false;
593 	uint64_t hcr_el2 = 0U;
594 
595 	assert(ctx != NULL);
596 
597 	if (security_state == NON_SECURE) {
598 		scr_el3 = read_ctx_reg(get_el3state_ctx(ctx),
599 						 CTX_SCR_EL3);
600 		if ((scr_el3 & SCR_HCE_BIT) != 0U) {
601 			/* Use SCTLR_EL1.EE value to initialise sctlr_el2 */
602 			sctlr_elx = read_ctx_reg(get_el1_sysregs_ctx(ctx),
603 							   CTX_SCTLR_EL1);
604 			sctlr_elx &= SCTLR_EE_BIT;
605 			sctlr_elx |= SCTLR_EL2_RES1;
606 #if ERRATA_A75_764081
607 			/*
608 			 * If workaround of errata 764081 for Cortex-A75 is used
609 			 * then set SCTLR_EL2.IESB to enable Implicit Error
610 			 * Synchronization Barrier.
611 			 */
612 			sctlr_elx |= SCTLR_IESB_BIT;
613 #endif
614 			write_sctlr_el2(sctlr_elx);
615 		} else if (el_implemented(2) != EL_IMPL_NONE) {
616 			el2_unused = true;
617 
618 			/*
619 			 * EL2 present but unused, need to disable safely.
620 			 * SCTLR_EL2 can be ignored in this case.
621 			 *
622 			 * Set EL2 register width appropriately: Set HCR_EL2
623 			 * field to match SCR_EL3.RW.
624 			 */
625 			if ((scr_el3 & SCR_RW_BIT) != 0U)
626 				hcr_el2 |= HCR_RW_BIT;
627 
628 			/*
629 			 * For Armv8.3 pointer authentication feature, disable
630 			 * traps to EL2 when accessing key registers or using
631 			 * pointer authentication instructions from lower ELs.
632 			 */
633 			hcr_el2 |= (HCR_API_BIT | HCR_APK_BIT);
634 
635 			write_hcr_el2(hcr_el2);
636 
637 			/*
638 			 * Initialise CPTR_EL2 setting all fields rather than
639 			 * relying on the hw. All fields have architecturally
640 			 * UNKNOWN reset values.
641 			 *
642 			 * CPTR_EL2.TCPAC: Set to zero so that Non-secure EL1
643 			 *  accesses to the CPACR_EL1 or CPACR from both
644 			 *  Execution states do not trap to EL2.
645 			 *
646 			 * CPTR_EL2.TTA: Set to zero so that Non-secure System
647 			 *  register accesses to the trace registers from both
648 			 *  Execution states do not trap to EL2.
649 			 *  If PE trace unit System registers are not implemented
650 			 *  then this bit is reserved, and must be set to zero.
651 			 *
652 			 * CPTR_EL2.TFP: Set to zero so that Non-secure accesses
653 			 *  to SIMD and floating-point functionality from both
654 			 *  Execution states do not trap to EL2.
655 			 */
656 			write_cptr_el2(CPTR_EL2_RESET_VAL &
657 					~(CPTR_EL2_TCPAC_BIT | CPTR_EL2_TTA_BIT
658 					| CPTR_EL2_TFP_BIT));
659 
660 			/*
661 			 * Initialise CNTHCTL_EL2. All fields are
662 			 * architecturally UNKNOWN on reset and are set to zero
663 			 * except for field(s) listed below.
664 			 *
665 			 * CNTHCTL_EL2.EL1PTEN: Set to one to disable traps to
666 			 *  Hyp mode of Non-secure EL0 and EL1 accesses to the
667 			 *  physical timer registers.
668 			 *
669 			 * CNTHCTL_EL2.EL1PCTEN: Set to one to disable traps to
670 			 *  Hyp mode of  Non-secure EL0 and EL1 accesses to the
671 			 *  physical counter registers.
672 			 */
673 			write_cnthctl_el2(CNTHCTL_RESET_VAL |
674 						EL1PCEN_BIT | EL1PCTEN_BIT);
675 
676 			/*
677 			 * Initialise CNTVOFF_EL2 to zero as it resets to an
678 			 * architecturally UNKNOWN value.
679 			 */
680 			write_cntvoff_el2(0);
681 
682 			/*
683 			 * Set VPIDR_EL2 and VMPIDR_EL2 to match MIDR_EL1 and
684 			 * MPIDR_EL1 respectively.
685 			 */
686 			write_vpidr_el2(read_midr_el1());
687 			write_vmpidr_el2(read_mpidr_el1());
688 
689 			/*
690 			 * Initialise VTTBR_EL2. All fields are architecturally
691 			 * UNKNOWN on reset.
692 			 *
693 			 * VTTBR_EL2.VMID: Set to zero. Even though EL1&0 stage
694 			 *  2 address translation is disabled, cache maintenance
695 			 *  operations depend on the VMID.
696 			 *
697 			 * VTTBR_EL2.BADDR: Set to zero as EL1&0 stage 2 address
698 			 *  translation is disabled.
699 			 */
700 			write_vttbr_el2(VTTBR_RESET_VAL &
701 				~((VTTBR_VMID_MASK << VTTBR_VMID_SHIFT)
702 				| (VTTBR_BADDR_MASK << VTTBR_BADDR_SHIFT)));
703 
704 			/*
705 			 * Initialise MDCR_EL2, setting all fields rather than
706 			 * relying on hw. Some fields are architecturally
707 			 * UNKNOWN on reset.
708 			 *
709 			 * MDCR_EL2.HLP: Set to one so that event counter
710 			 *  overflow, that is recorded in PMOVSCLR_EL0[0-30],
711 			 *  occurs on the increment that changes
712 			 *  PMEVCNTR<n>_EL0[63] from 1 to 0, when ARMv8.5-PMU is
713 			 *  implemented. This bit is RES0 in versions of the
714 			 *  architecture earlier than ARMv8.5, setting it to 1
715 			 *  doesn't have any effect on them.
716 			 *
717 			 * MDCR_EL2.TTRF: Set to zero so that access to Trace
718 			 *  Filter Control register TRFCR_EL1 at EL1 is not
719 			 *  trapped to EL2. This bit is RES0 in versions of
720 			 *  the architecture earlier than ARMv8.4.
721 			 *
722 			 * MDCR_EL2.HPMD: Set to one so that event counting is
723 			 *  prohibited at EL2. This bit is RES0 in versions of
724 			 *  the architecture earlier than ARMv8.1, setting it
725 			 *  to 1 doesn't have any effect on them.
726 			 *
727 			 * MDCR_EL2.TPMS: Set to zero so that accesses to
728 			 *  Statistical Profiling control registers from EL1
729 			 *  do not trap to EL2. This bit is RES0 when SPE is
730 			 *  not implemented.
731 			 *
732 			 * MDCR_EL2.TDRA: Set to zero so that Non-secure EL0 and
733 			 *  EL1 System register accesses to the Debug ROM
734 			 *  registers are not trapped to EL2.
735 			 *
736 			 * MDCR_EL2.TDOSA: Set to zero so that Non-secure EL1
737 			 *  System register accesses to the powerdown debug
738 			 *  registers are not trapped to EL2.
739 			 *
740 			 * MDCR_EL2.TDA: Set to zero so that System register
741 			 *  accesses to the debug registers do not trap to EL2.
742 			 *
743 			 * MDCR_EL2.TDE: Set to zero so that debug exceptions
744 			 *  are not routed to EL2.
745 			 *
746 			 * MDCR_EL2.HPME: Set to zero to disable EL2 Performance
747 			 *  Monitors.
748 			 *
749 			 * MDCR_EL2.TPM: Set to zero so that Non-secure EL0 and
750 			 *  EL1 accesses to all Performance Monitors registers
751 			 *  are not trapped to EL2.
752 			 *
753 			 * MDCR_EL2.TPMCR: Set to zero so that Non-secure EL0
754 			 *  and EL1 accesses to the PMCR_EL0 or PMCR are not
755 			 *  trapped to EL2.
756 			 *
757 			 * MDCR_EL2.HPMN: Set to value of PMCR_EL0.N which is the
758 			 *  architecturally-defined reset value.
759 			 *
760 			 * MDCR_EL2.E2TB: Set to zero so that the trace Buffer
761 			 *  owning exception level is NS-EL1 and, tracing is
762 			 *  prohibited at NS-EL2. These bits are RES0 when
763 			 *  FEAT_TRBE is not implemented.
764 			 */
765 			mdcr_el2 = ((MDCR_EL2_RESET_VAL | MDCR_EL2_HLP |
766 				     MDCR_EL2_HPMD) |
767 				   ((read_pmcr_el0() & PMCR_EL0_N_BITS)
768 				   >> PMCR_EL0_N_SHIFT)) &
769 				   ~(MDCR_EL2_TTRF | MDCR_EL2_TPMS |
770 				     MDCR_EL2_TDRA_BIT | MDCR_EL2_TDOSA_BIT |
771 				     MDCR_EL2_TDA_BIT | MDCR_EL2_TDE_BIT |
772 				     MDCR_EL2_HPME_BIT | MDCR_EL2_TPM_BIT |
773 				     MDCR_EL2_TPMCR_BIT |
774 				     MDCR_EL2_E2TB(MDCR_EL2_E2TB_EL1));
775 
776 			write_mdcr_el2(mdcr_el2);
777 
778 			/*
779 			 * Initialise HSTR_EL2. All fields are architecturally
780 			 * UNKNOWN on reset.
781 			 *
782 			 * HSTR_EL2.T<n>: Set all these fields to zero so that
783 			 *  Non-secure EL0 or EL1 accesses to System registers
784 			 *  do not trap to EL2.
785 			 */
786 			write_hstr_el2(HSTR_EL2_RESET_VAL & ~(HSTR_EL2_T_MASK));
787 			/*
788 			 * Initialise CNTHP_CTL_EL2. All fields are
789 			 * architecturally UNKNOWN on reset.
790 			 *
791 			 * CNTHP_CTL_EL2:ENABLE: Set to zero to disable the EL2
792 			 *  physical timer and prevent timer interrupts.
793 			 */
794 			write_cnthp_ctl_el2(CNTHP_CTL_RESET_VAL &
795 						~(CNTHP_CTL_ENABLE_BIT));
796 		}
797 		manage_extensions_nonsecure(el2_unused, ctx);
798 	}
799 
800 	cm_el1_sysregs_context_restore(security_state);
801 	cm_set_next_eret_context(security_state);
802 }
803 
804 #if CTX_INCLUDE_EL2_REGS
805 
806 static void el2_sysregs_context_save_fgt(el2_sysregs_t *ctx)
807 {
808 	write_ctx_reg(ctx, CTX_HDFGRTR_EL2, read_hdfgrtr_el2());
809 	if (is_feat_amu_supported()) {
810 		write_ctx_reg(ctx, CTX_HAFGRTR_EL2, read_hafgrtr_el2());
811 	}
812 	write_ctx_reg(ctx, CTX_HDFGWTR_EL2, read_hdfgwtr_el2());
813 	write_ctx_reg(ctx, CTX_HFGITR_EL2, read_hfgitr_el2());
814 	write_ctx_reg(ctx, CTX_HFGRTR_EL2, read_hfgrtr_el2());
815 	write_ctx_reg(ctx, CTX_HFGWTR_EL2, read_hfgwtr_el2());
816 }
817 
818 static void el2_sysregs_context_restore_fgt(el2_sysregs_t *ctx)
819 {
820 	write_hdfgrtr_el2(read_ctx_reg(ctx, CTX_HDFGRTR_EL2));
821 	if (is_feat_amu_supported()) {
822 		write_hafgrtr_el2(read_ctx_reg(ctx, CTX_HAFGRTR_EL2));
823 	}
824 	write_hdfgwtr_el2(read_ctx_reg(ctx, CTX_HDFGWTR_EL2));
825 	write_hfgitr_el2(read_ctx_reg(ctx, CTX_HFGITR_EL2));
826 	write_hfgrtr_el2(read_ctx_reg(ctx, CTX_HFGRTR_EL2));
827 	write_hfgwtr_el2(read_ctx_reg(ctx, CTX_HFGWTR_EL2));
828 }
829 
830 /*******************************************************************************
831  * Save EL2 sysreg context
832  ******************************************************************************/
833 void cm_el2_sysregs_context_save(uint32_t security_state)
834 {
835 	u_register_t scr_el3 = read_scr();
836 
837 	/*
838 	 * Always save the non-secure and realm EL2 context, only save the
839 	 * S-EL2 context if S-EL2 is enabled.
840 	 */
841 	if ((security_state != SECURE) ||
842 	    ((security_state == SECURE) && ((scr_el3 & SCR_EEL2_BIT) != 0U))) {
843 		cpu_context_t *ctx;
844 		el2_sysregs_t *el2_sysregs_ctx;
845 
846 		ctx = cm_get_context(security_state);
847 		assert(ctx != NULL);
848 
849 		el2_sysregs_ctx = get_el2_sysregs_ctx(ctx);
850 
851 		el2_sysregs_context_save_common(el2_sysregs_ctx);
852 #if ENABLE_SPE_FOR_LOWER_ELS
853 		el2_sysregs_context_save_spe(el2_sysregs_ctx);
854 #endif
855 #if CTX_INCLUDE_MTE_REGS
856 		el2_sysregs_context_save_mte(el2_sysregs_ctx);
857 #endif
858 #if ENABLE_MPAM_FOR_LOWER_ELS
859 		el2_sysregs_context_save_mpam(el2_sysregs_ctx);
860 #endif
861 
862 		if (is_feat_fgt_supported()) {
863 			el2_sysregs_context_save_fgt(el2_sysregs_ctx);
864 		}
865 
866 #if ENABLE_FEAT_ECV
867 		el2_sysregs_context_save_ecv(el2_sysregs_ctx);
868 #endif
869 #if ENABLE_FEAT_VHE
870 		el2_sysregs_context_save_vhe(el2_sysregs_ctx);
871 #endif
872 #if RAS_EXTENSION
873 		el2_sysregs_context_save_ras(el2_sysregs_ctx);
874 #endif
875 #if CTX_INCLUDE_NEVE_REGS
876 		el2_sysregs_context_save_nv2(el2_sysregs_ctx);
877 #endif
878 		if (is_feat_trf_supported()) {
879 			write_ctx_reg(el2_sysregs_ctx, CTX_TRFCR_EL2, read_trfcr_el2());
880 		}
881 #if ENABLE_FEAT_CSV2_2
882 		el2_sysregs_context_save_csv2(el2_sysregs_ctx);
883 #endif
884 		if (is_feat_hcx_supported()) {
885 			write_ctx_reg(el2_sysregs_ctx, CTX_HCRX_EL2, read_hcrx_el2());
886 		}
887 	}
888 }
889 
890 /*******************************************************************************
891  * Restore EL2 sysreg context
892  ******************************************************************************/
893 void cm_el2_sysregs_context_restore(uint32_t security_state)
894 {
895 	u_register_t scr_el3 = read_scr();
896 
897 	/*
898 	 * Always restore the non-secure and realm EL2 context, only restore the
899 	 * S-EL2 context if S-EL2 is enabled.
900 	 */
901 	if ((security_state != SECURE) ||
902 	    ((security_state == SECURE) && ((scr_el3 & SCR_EEL2_BIT) != 0U))) {
903 		cpu_context_t *ctx;
904 		el2_sysregs_t *el2_sysregs_ctx;
905 
906 		ctx = cm_get_context(security_state);
907 		assert(ctx != NULL);
908 
909 		el2_sysregs_ctx = get_el2_sysregs_ctx(ctx);
910 
911 		el2_sysregs_context_restore_common(el2_sysregs_ctx);
912 #if ENABLE_SPE_FOR_LOWER_ELS
913 		el2_sysregs_context_restore_spe(el2_sysregs_ctx);
914 #endif
915 #if CTX_INCLUDE_MTE_REGS
916 		el2_sysregs_context_restore_mte(el2_sysregs_ctx);
917 #endif
918 #if ENABLE_MPAM_FOR_LOWER_ELS
919 		el2_sysregs_context_restore_mpam(el2_sysregs_ctx);
920 #endif
921 
922 		if (is_feat_fgt_supported()) {
923 			el2_sysregs_context_restore_fgt(el2_sysregs_ctx);
924 		}
925 
926 #if ENABLE_FEAT_ECV
927 		el2_sysregs_context_restore_ecv(el2_sysregs_ctx);
928 #endif
929 #if ENABLE_FEAT_VHE
930 		el2_sysregs_context_restore_vhe(el2_sysregs_ctx);
931 #endif
932 #if RAS_EXTENSION
933 		el2_sysregs_context_restore_ras(el2_sysregs_ctx);
934 #endif
935 #if CTX_INCLUDE_NEVE_REGS
936 		el2_sysregs_context_restore_nv2(el2_sysregs_ctx);
937 #endif
938 		if (is_feat_trf_supported()) {
939 			write_trfcr_el2(read_ctx_reg(el2_sysregs_ctx, CTX_TRFCR_EL2));
940 		}
941 #if ENABLE_FEAT_CSV2_2
942 		el2_sysregs_context_restore_csv2(el2_sysregs_ctx);
943 #endif
944 		if (is_feat_hcx_supported()) {
945 			write_hcrx_el2(read_ctx_reg(el2_sysregs_ctx, CTX_HCRX_EL2));
946 		}
947 	}
948 }
949 #endif /* CTX_INCLUDE_EL2_REGS */
950 
951 /*******************************************************************************
952  * This function is used to exit to Non-secure world. If CTX_INCLUDE_EL2_REGS
953  * is enabled, it restores EL1 and EL2 sysreg contexts instead of directly
954  * updating EL1 and EL2 registers. Otherwise, it calls the generic
955  * cm_prepare_el3_exit function.
956  ******************************************************************************/
957 void cm_prepare_el3_exit_ns(void)
958 {
959 #if CTX_INCLUDE_EL2_REGS
960 	cpu_context_t *ctx = cm_get_context(NON_SECURE);
961 	assert(ctx != NULL);
962 
963 	/* Assert that EL2 is used. */
964 #if ENABLE_ASSERTIONS
965 	el3_state_t *state = get_el3state_ctx(ctx);
966 	u_register_t scr_el3 = read_ctx_reg(state, CTX_SCR_EL3);
967 #endif
968 	assert(((scr_el3 & SCR_HCE_BIT) != 0UL) &&
969 			(el_implemented(2U) != EL_IMPL_NONE));
970 
971 	/*
972 	 * Currently some extensions are configured using
973 	 * direct register updates. Therefore, do this here
974 	 * instead of when setting up context.
975 	 */
976 	manage_extensions_nonsecure(0, ctx);
977 
978 	/*
979 	 * Set the NS bit to be able to access the ICC_SRE_EL2
980 	 * register when restoring context.
981 	 */
982 	write_scr_el3(read_scr_el3() | SCR_NS_BIT);
983 
984 	/*
985 	 * Ensure the NS bit change is committed before the EL2/EL1
986 	 * state restoration.
987 	 */
988 	isb();
989 
990 	/* Restore EL2 and EL1 sysreg contexts */
991 	cm_el2_sysregs_context_restore(NON_SECURE);
992 	cm_el1_sysregs_context_restore(NON_SECURE);
993 	cm_set_next_eret_context(NON_SECURE);
994 #else
995 	cm_prepare_el3_exit(NON_SECURE);
996 #endif /* CTX_INCLUDE_EL2_REGS */
997 }
998 
999 /*******************************************************************************
1000  * The next four functions are used by runtime services to save and restore
1001  * EL1 context on the 'cpu_context' structure for the specified security
1002  * state.
1003  ******************************************************************************/
1004 void cm_el1_sysregs_context_save(uint32_t security_state)
1005 {
1006 	cpu_context_t *ctx;
1007 
1008 	ctx = cm_get_context(security_state);
1009 	assert(ctx != NULL);
1010 
1011 	el1_sysregs_context_save(get_el1_sysregs_ctx(ctx));
1012 
1013 #if IMAGE_BL31
1014 	if (security_state == SECURE)
1015 		PUBLISH_EVENT(cm_exited_secure_world);
1016 	else
1017 		PUBLISH_EVENT(cm_exited_normal_world);
1018 #endif
1019 }
1020 
1021 void cm_el1_sysregs_context_restore(uint32_t security_state)
1022 {
1023 	cpu_context_t *ctx;
1024 
1025 	ctx = cm_get_context(security_state);
1026 	assert(ctx != NULL);
1027 
1028 	el1_sysregs_context_restore(get_el1_sysregs_ctx(ctx));
1029 
1030 #if IMAGE_BL31
1031 	if (security_state == SECURE)
1032 		PUBLISH_EVENT(cm_entering_secure_world);
1033 	else
1034 		PUBLISH_EVENT(cm_entering_normal_world);
1035 #endif
1036 }
1037 
1038 /*******************************************************************************
1039  * This function populates ELR_EL3 member of 'cpu_context' pertaining to the
1040  * given security state with the given entrypoint
1041  ******************************************************************************/
1042 void cm_set_elr_el3(uint32_t security_state, uintptr_t entrypoint)
1043 {
1044 	cpu_context_t *ctx;
1045 	el3_state_t *state;
1046 
1047 	ctx = cm_get_context(security_state);
1048 	assert(ctx != NULL);
1049 
1050 	/* Populate EL3 state so that ERET jumps to the correct entry */
1051 	state = get_el3state_ctx(ctx);
1052 	write_ctx_reg(state, CTX_ELR_EL3, entrypoint);
1053 }
1054 
1055 /*******************************************************************************
1056  * This function populates ELR_EL3 and SPSR_EL3 members of 'cpu_context'
1057  * pertaining to the given security state
1058  ******************************************************************************/
1059 void cm_set_elr_spsr_el3(uint32_t security_state,
1060 			uintptr_t entrypoint, uint32_t spsr)
1061 {
1062 	cpu_context_t *ctx;
1063 	el3_state_t *state;
1064 
1065 	ctx = cm_get_context(security_state);
1066 	assert(ctx != NULL);
1067 
1068 	/* Populate EL3 state so that ERET jumps to the correct entry */
1069 	state = get_el3state_ctx(ctx);
1070 	write_ctx_reg(state, CTX_ELR_EL3, entrypoint);
1071 	write_ctx_reg(state, CTX_SPSR_EL3, spsr);
1072 }
1073 
1074 /*******************************************************************************
1075  * This function updates a single bit in the SCR_EL3 member of the 'cpu_context'
1076  * pertaining to the given security state using the value and bit position
1077  * specified in the parameters. It preserves all other bits.
1078  ******************************************************************************/
1079 void cm_write_scr_el3_bit(uint32_t security_state,
1080 			  uint32_t bit_pos,
1081 			  uint32_t value)
1082 {
1083 	cpu_context_t *ctx;
1084 	el3_state_t *state;
1085 	u_register_t scr_el3;
1086 
1087 	ctx = cm_get_context(security_state);
1088 	assert(ctx != NULL);
1089 
1090 	/* Ensure that the bit position is a valid one */
1091 	assert(((1UL << bit_pos) & SCR_VALID_BIT_MASK) != 0U);
1092 
1093 	/* Ensure that the 'value' is only a bit wide */
1094 	assert(value <= 1U);
1095 
1096 	/*
1097 	 * Get the SCR_EL3 value from the cpu context, clear the desired bit
1098 	 * and set it to its new value.
1099 	 */
1100 	state = get_el3state_ctx(ctx);
1101 	scr_el3 = read_ctx_reg(state, CTX_SCR_EL3);
1102 	scr_el3 &= ~(1UL << bit_pos);
1103 	scr_el3 |= (u_register_t)value << bit_pos;
1104 	write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
1105 }
1106 
1107 /*******************************************************************************
1108  * This function retrieves SCR_EL3 member of 'cpu_context' pertaining to the
1109  * given security state.
1110  ******************************************************************************/
1111 u_register_t cm_get_scr_el3(uint32_t security_state)
1112 {
1113 	cpu_context_t *ctx;
1114 	el3_state_t *state;
1115 
1116 	ctx = cm_get_context(security_state);
1117 	assert(ctx != NULL);
1118 
1119 	/* Populate EL3 state so that ERET jumps to the correct entry */
1120 	state = get_el3state_ctx(ctx);
1121 	return read_ctx_reg(state, CTX_SCR_EL3);
1122 }
1123 
1124 /*******************************************************************************
1125  * This function is used to program the context that's used for exception
1126  * return. This initializes the SP_EL3 to a pointer to a 'cpu_context' set for
1127  * the required security state
1128  ******************************************************************************/
1129 void cm_set_next_eret_context(uint32_t security_state)
1130 {
1131 	cpu_context_t *ctx;
1132 
1133 	ctx = cm_get_context(security_state);
1134 	assert(ctx != NULL);
1135 
1136 	cm_set_next_context(ctx);
1137 }
1138