xref: /rk3399_ARM-atf/lib/el3_runtime/aarch64/context_mgmt.c (revision ddb615b419074727ac0a1430cf0f88bd018ac8df)
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_feat_sel2_supported()) {
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 (is_feat_csv2_2_supported()) {
175 		/* Enable access to the SCXTNUM_ELx registers. */
176 		scr_el3 |= SCR_EnSCXT_BIT;
177 	}
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 (is_feat_csv2_2_supported()) {
231 		/* Enable access to the SCXTNUM_ELx registers. */
232 		scr_el3 |= SCR_EnSCXT_BIT;
233 	}
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 
278 	if (is_feat_hcx_supported()) {
279 		/*
280 		 * Initialize register HCRX_EL2 with its init value.
281 		 * As the value of HCRX_EL2 is UNKNOWN on reset, there is a
282 		 * chance that this can lead to unexpected behavior in lower
283 		 * ELs that have not been updated since the introduction of
284 		 * this feature if not properly initialized, especially when
285 		 * it comes to those bits that enable/disable traps.
286 		 */
287 		write_ctx_reg(get_el2_sysregs_ctx(ctx), CTX_HCRX_EL2,
288 			HCRX_EL2_INIT_VAL);
289 	}
290 #endif /* CTX_INCLUDE_EL2_REGS */
291 }
292 
293 /*******************************************************************************
294  * The following function performs initialization of the cpu_context 'ctx'
295  * for first use that is common to all security states, and sets the
296  * initial entrypoint state as specified by the entry_point_info structure.
297  *
298  * The EE and ST attributes are used to configure the endianness and secure
299  * timer availability for the new execution context.
300  ******************************************************************************/
301 static void setup_context_common(cpu_context_t *ctx, const entry_point_info_t *ep)
302 {
303 	u_register_t scr_el3;
304 	el3_state_t *state;
305 	gp_regs_t *gp_regs;
306 
307 	/* Clear any residual register values from the context */
308 	zeromem(ctx, sizeof(*ctx));
309 
310 	/*
311 	 * SCR_EL3 was initialised during reset sequence in macro
312 	 * el3_arch_init_common. This code modifies the SCR_EL3 fields that
313 	 * affect the next EL.
314 	 *
315 	 * The following fields are initially set to zero and then updated to
316 	 * the required value depending on the state of the SPSR_EL3 and the
317 	 * Security state and entrypoint attributes of the next EL.
318 	 */
319 	scr_el3 = read_scr();
320 	scr_el3 &= ~(SCR_NS_BIT | SCR_RW_BIT | SCR_EA_BIT | SCR_FIQ_BIT | SCR_IRQ_BIT |
321 			SCR_ST_BIT | SCR_HCE_BIT | SCR_NSE_BIT);
322 
323 	/*
324 	 * SCR_EL3.RW: Set the execution state, AArch32 or AArch64, for next
325 	 *  Exception level as specified by SPSR.
326 	 */
327 	if (GET_RW(ep->spsr) == MODE_RW_64) {
328 		scr_el3 |= SCR_RW_BIT;
329 	}
330 
331 	/*
332 	 * SCR_EL3.ST: Traps Secure EL1 accesses to the Counter-timer Physical
333 	 * Secure timer registers to EL3, from AArch64 state only, if specified
334 	 * by the entrypoint attributes. If SEL2 is present and enabled, the ST
335 	 * bit always behaves as 1 (i.e. secure physical timer register access
336 	 * is not trapped)
337 	 */
338 	if (EP_GET_ST(ep->h.attr) != 0U) {
339 		scr_el3 |= SCR_ST_BIT;
340 	}
341 
342 	/*
343 	 * If FEAT_HCX is enabled, enable access to HCRX_EL2 by setting
344 	 * SCR_EL3.HXEn.
345 	 */
346 	if (is_feat_hcx_supported()) {
347 		scr_el3 |= SCR_HXEn_BIT;
348 	}
349 
350 	/*
351 	 * If FEAT_RNG_TRAP is enabled, all reads of the RNDR and RNDRRS
352 	 * registers are trapped to EL3.
353 	 */
354 #if ENABLE_FEAT_RNG_TRAP
355 	scr_el3 |= SCR_TRNDR_BIT;
356 #endif
357 
358 #if FAULT_INJECTION_SUPPORT
359 	/* Enable fault injection from lower ELs */
360 	scr_el3 |= SCR_FIEN_BIT;
361 #endif
362 
363 	/*
364 	 * SCR_EL3.TCR2EN: Enable access to TCR2_ELx for AArch64 if present.
365 	 */
366 	if (is_feat_tcr2_supported() && (GET_RW(ep->spsr) == MODE_RW_64)) {
367 		scr_el3 |= SCR_TCR2EN_BIT;
368 	}
369 
370 	/*
371 	 * CPTR_EL3 was initialized out of reset, copy that value to the
372 	 * context register.
373 	 */
374 	write_ctx_reg(get_el3state_ctx(ctx), CTX_CPTR_EL3, read_cptr_el3());
375 
376 	/*
377 	 * SCR_EL3.HCE: Enable HVC instructions if next execution state is
378 	 * AArch64 and next EL is EL2, or if next execution state is AArch32 and
379 	 * next mode is Hyp.
380 	 * SCR_EL3.FGTEn: Enable Fine Grained Virtualization Traps under the
381 	 * same conditions as HVC instructions and when the processor supports
382 	 * ARMv8.6-FGT.
383 	 * SCR_EL3.ECVEn: Enable Enhanced Counter Virtualization (ECV)
384 	 * CNTPOFF_EL2 register under the same conditions as HVC instructions
385 	 * and when the processor supports ECV.
386 	 */
387 	if (((GET_RW(ep->spsr) == MODE_RW_64) && (GET_EL(ep->spsr) == MODE_EL2))
388 	    || ((GET_RW(ep->spsr) != MODE_RW_64)
389 		&& (GET_M32(ep->spsr) == MODE32_hyp))) {
390 		scr_el3 |= SCR_HCE_BIT;
391 
392 		if (is_feat_fgt_supported()) {
393 			scr_el3 |= SCR_FGTEN_BIT;
394 		}
395 
396 		if (is_feat_ecv_supported()) {
397 			scr_el3 |= SCR_ECVEN_BIT;
398 		}
399 	}
400 
401 	/* Enable WFE trap delay in SCR_EL3 if supported and configured */
402 	if (is_feat_twed_supported()) {
403 		/* Set delay in SCR_EL3 */
404 		scr_el3 &= ~(SCR_TWEDEL_MASK << SCR_TWEDEL_SHIFT);
405 		scr_el3 |= ((TWED_DELAY & SCR_TWEDEL_MASK)
406 				<< SCR_TWEDEL_SHIFT);
407 
408 		/* Enable WFE delay */
409 		scr_el3 |= SCR_TWEDEn_BIT;
410 	}
411 
412 	/*
413 	 * Populate EL3 state so that we've the right context
414 	 * before doing ERET
415 	 */
416 	state = get_el3state_ctx(ctx);
417 	write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
418 	write_ctx_reg(state, CTX_ELR_EL3, ep->pc);
419 	write_ctx_reg(state, CTX_SPSR_EL3, ep->spsr);
420 
421 	/*
422 	 * Store the X0-X7 value from the entrypoint into the context
423 	 * Use memcpy as we are in control of the layout of the structures
424 	 */
425 	gp_regs = get_gpregs_ctx(ctx);
426 	memcpy(gp_regs, (void *)&ep->args, sizeof(aapcs64_params_t));
427 }
428 
429 /*******************************************************************************
430  * Context management library initialization routine. This library is used by
431  * runtime services to share pointers to 'cpu_context' structures for secure
432  * non-secure and realm states. Management of the structures and their associated
433  * memory is not done by the context management library e.g. the PSCI service
434  * manages the cpu context used for entry from and exit to the non-secure state.
435  * The Secure payload dispatcher service manages the context(s) corresponding to
436  * the secure state. It also uses this library to get access to the non-secure
437  * state cpu context pointers.
438  * Lastly, this library provides the API to make SP_EL3 point to the cpu context
439  * which will be used for programming an entry into a lower EL. The same context
440  * will be used to save state upon exception entry from that EL.
441  ******************************************************************************/
442 void __init cm_init(void)
443 {
444 	/*
445 	 * The context management library has only global data to intialize, but
446 	 * that will be done when the BSS is zeroed out.
447 	 */
448 }
449 
450 /*******************************************************************************
451  * This is the high-level function used to initialize the cpu_context 'ctx' for
452  * first use. It performs initializations that are common to all security states
453  * and initializations specific to the security state specified in 'ep'
454  ******************************************************************************/
455 void cm_setup_context(cpu_context_t *ctx, const entry_point_info_t *ep)
456 {
457 	unsigned int security_state;
458 
459 	assert(ctx != NULL);
460 
461 	/*
462 	 * Perform initializations that are common
463 	 * to all security states
464 	 */
465 	setup_context_common(ctx, ep);
466 
467 	security_state = GET_SECURITY_STATE(ep->h.attr);
468 
469 	/* Perform security state specific initializations */
470 	switch (security_state) {
471 	case SECURE:
472 		setup_secure_context(ctx, ep);
473 		break;
474 #if ENABLE_RME
475 	case REALM:
476 		setup_realm_context(ctx, ep);
477 		break;
478 #endif
479 	case NON_SECURE:
480 		setup_ns_context(ctx, ep);
481 		break;
482 	default:
483 		ERROR("Invalid security state\n");
484 		panic();
485 		break;
486 	}
487 }
488 
489 /*******************************************************************************
490  * Enable architecture extensions on first entry to Non-secure world.
491  * When EL2 is implemented but unused `el2_unused` is non-zero, otherwise
492  * it is zero.
493  ******************************************************************************/
494 static void manage_extensions_nonsecure(bool el2_unused, cpu_context_t *ctx)
495 {
496 #if IMAGE_BL31
497 	if (is_feat_spe_supported()) {
498 		spe_enable(el2_unused);
499 	}
500 
501 	if (is_feat_amu_supported()) {
502 		amu_enable(el2_unused, ctx);
503 	}
504 
505 	/* Enable SME, SVE, and FPU/SIMD for non-secure world. */
506 	if (is_feat_sme_supported()) {
507 		sme_enable(ctx);
508 	} else if (is_feat_sve_supported()) {
509 		/* Enable SVE and FPU/SIMD for non-secure world. */
510 		sve_enable(ctx);
511 	}
512 
513 	if (is_feat_mpam_supported()) {
514 		mpam_enable(el2_unused);
515 	}
516 
517 	if (is_feat_trbe_supported()) {
518 		trbe_enable();
519 	}
520 
521 	if (is_feat_brbe_supported()) {
522 		brbe_enable();
523 	}
524 
525 	if (is_feat_sys_reg_trace_supported()) {
526 		sys_reg_trace_enable(ctx);
527 	}
528 
529 	if (is_feat_trf_supported()) {
530 		trf_enable();
531 	}
532 #endif
533 }
534 
535 /*******************************************************************************
536  * Enable architecture extensions on first entry to Secure world.
537  ******************************************************************************/
538 static void manage_extensions_secure(cpu_context_t *ctx)
539 {
540 #if IMAGE_BL31
541 
542 	if (is_feat_sme_supported()) {
543 		if (ENABLE_SME_FOR_SWD) {
544 		/*
545 		 * Enable SME, SVE, FPU/SIMD in secure context, secure manager
546 		 * must ensure SME, SVE, and FPU/SIMD context properly managed.
547 		 */
548 			sme_enable(ctx);
549 		} else {
550 		/*
551 		 * Disable SME, SVE, FPU/SIMD in secure context so non-secure
552 		 * world can safely use the associated registers.
553 		 */
554 			sme_disable(ctx);
555 		}
556 	} else if (is_feat_sve_supported()) {
557 		if (ENABLE_SVE_FOR_SWD) {
558 		/*
559 		 * Enable SVE and FPU in secure context, secure manager must
560 		 * ensure that the SVE and FPU register contexts are properly
561 		 * managed.
562 		 */
563 			sve_enable(ctx);
564 		} else {
565 		/*
566 		 * Disable SVE and FPU in secure context so non-secure world
567 		 * can safely use them.
568 		 */
569 			sve_disable(ctx);
570 		}
571 	}
572 
573 #endif /* IMAGE_BL31 */
574 }
575 
576 /*******************************************************************************
577  * The following function initializes the cpu_context for a CPU specified by
578  * its `cpu_idx` for first use, and sets the initial entrypoint state as
579  * specified by the entry_point_info structure.
580  ******************************************************************************/
581 void cm_init_context_by_index(unsigned int cpu_idx,
582 			      const entry_point_info_t *ep)
583 {
584 	cpu_context_t *ctx;
585 	ctx = cm_get_context_by_index(cpu_idx, GET_SECURITY_STATE(ep->h.attr));
586 	cm_setup_context(ctx, ep);
587 }
588 
589 /*******************************************************************************
590  * The following function initializes the cpu_context for the current CPU
591  * for first use, and sets the initial entrypoint state as specified by the
592  * entry_point_info structure.
593  ******************************************************************************/
594 void cm_init_my_context(const entry_point_info_t *ep)
595 {
596 	cpu_context_t *ctx;
597 	ctx = cm_get_context(GET_SECURITY_STATE(ep->h.attr));
598 	cm_setup_context(ctx, ep);
599 }
600 
601 /*******************************************************************************
602  * Prepare the CPU system registers for first entry into realm, secure, or
603  * normal world.
604  *
605  * If execution is requested to EL2 or hyp mode, SCTLR_EL2 is initialized
606  * If execution is requested to non-secure EL1 or svc mode, and the CPU supports
607  * EL2 then EL2 is disabled by configuring all necessary EL2 registers.
608  * For all entries, the EL1 registers are initialized from the cpu_context
609  ******************************************************************************/
610 void cm_prepare_el3_exit(uint32_t security_state)
611 {
612 	u_register_t sctlr_elx, scr_el3, mdcr_el2;
613 	cpu_context_t *ctx = cm_get_context(security_state);
614 	bool el2_unused = false;
615 	uint64_t hcr_el2 = 0U;
616 
617 	assert(ctx != NULL);
618 
619 	if (security_state == NON_SECURE) {
620 		uint64_t el2_implemented = el_implemented(2);
621 
622 		scr_el3 = read_ctx_reg(get_el3state_ctx(ctx),
623 						 CTX_SCR_EL3);
624 
625 		if (((scr_el3 & SCR_HCE_BIT) != 0U)
626 			|| (el2_implemented != EL_IMPL_NONE)) {
627 			/*
628 			 * If context is not being used for EL2, initialize
629 			 * HCRX_EL2 with its init value here.
630 			 */
631 			if (is_feat_hcx_supported()) {
632 				write_hcrx_el2(HCRX_EL2_INIT_VAL);
633 			}
634 		}
635 
636 		if ((scr_el3 & SCR_HCE_BIT) != 0U) {
637 			/* Use SCTLR_EL1.EE value to initialise sctlr_el2 */
638 			sctlr_elx = read_ctx_reg(get_el1_sysregs_ctx(ctx),
639 							   CTX_SCTLR_EL1);
640 			sctlr_elx &= SCTLR_EE_BIT;
641 			sctlr_elx |= SCTLR_EL2_RES1;
642 #if ERRATA_A75_764081
643 			/*
644 			 * If workaround of errata 764081 for Cortex-A75 is used
645 			 * then set SCTLR_EL2.IESB to enable Implicit Error
646 			 * Synchronization Barrier.
647 			 */
648 			sctlr_elx |= SCTLR_IESB_BIT;
649 #endif
650 			write_sctlr_el2(sctlr_elx);
651 		} else if (el2_implemented != EL_IMPL_NONE) {
652 			el2_unused = true;
653 
654 			/*
655 			 * EL2 present but unused, need to disable safely.
656 			 * SCTLR_EL2 can be ignored in this case.
657 			 *
658 			 * Set EL2 register width appropriately: Set HCR_EL2
659 			 * field to match SCR_EL3.RW.
660 			 */
661 			if ((scr_el3 & SCR_RW_BIT) != 0U)
662 				hcr_el2 |= HCR_RW_BIT;
663 
664 			/*
665 			 * For Armv8.3 pointer authentication feature, disable
666 			 * traps to EL2 when accessing key registers or using
667 			 * pointer authentication instructions from lower ELs.
668 			 */
669 			hcr_el2 |= (HCR_API_BIT | HCR_APK_BIT);
670 
671 			write_hcr_el2(hcr_el2);
672 
673 			/*
674 			 * Initialise CPTR_EL2 setting all fields rather than
675 			 * relying on the hw. All fields have architecturally
676 			 * UNKNOWN reset values.
677 			 *
678 			 * CPTR_EL2.TCPAC: Set to zero so that Non-secure EL1
679 			 *  accesses to the CPACR_EL1 or CPACR from both
680 			 *  Execution states do not trap to EL2.
681 			 *
682 			 * CPTR_EL2.TTA: Set to zero so that Non-secure System
683 			 *  register accesses to the trace registers from both
684 			 *  Execution states do not trap to EL2.
685 			 *  If PE trace unit System registers are not implemented
686 			 *  then this bit is reserved, and must be set to zero.
687 			 *
688 			 * CPTR_EL2.TFP: Set to zero so that Non-secure accesses
689 			 *  to SIMD and floating-point functionality from both
690 			 *  Execution states do not trap to EL2.
691 			 */
692 			write_cptr_el2(CPTR_EL2_RESET_VAL &
693 					~(CPTR_EL2_TCPAC_BIT | CPTR_EL2_TTA_BIT
694 					| CPTR_EL2_TFP_BIT));
695 
696 			/*
697 			 * Initialise CNTHCTL_EL2. All fields are
698 			 * architecturally UNKNOWN on reset and are set to zero
699 			 * except for field(s) listed below.
700 			 *
701 			 * CNTHCTL_EL2.EL1PTEN: Set to one to disable traps to
702 			 *  Hyp mode of Non-secure EL0 and EL1 accesses to the
703 			 *  physical timer registers.
704 			 *
705 			 * CNTHCTL_EL2.EL1PCTEN: Set to one to disable traps to
706 			 *  Hyp mode of  Non-secure EL0 and EL1 accesses to the
707 			 *  physical counter registers.
708 			 */
709 			write_cnthctl_el2(CNTHCTL_RESET_VAL |
710 						EL1PCEN_BIT | EL1PCTEN_BIT);
711 
712 			/*
713 			 * Initialise CNTVOFF_EL2 to zero as it resets to an
714 			 * architecturally UNKNOWN value.
715 			 */
716 			write_cntvoff_el2(0);
717 
718 			/*
719 			 * Set VPIDR_EL2 and VMPIDR_EL2 to match MIDR_EL1 and
720 			 * MPIDR_EL1 respectively.
721 			 */
722 			write_vpidr_el2(read_midr_el1());
723 			write_vmpidr_el2(read_mpidr_el1());
724 
725 			/*
726 			 * Initialise VTTBR_EL2. All fields are architecturally
727 			 * UNKNOWN on reset.
728 			 *
729 			 * VTTBR_EL2.VMID: Set to zero. Even though EL1&0 stage
730 			 *  2 address translation is disabled, cache maintenance
731 			 *  operations depend on the VMID.
732 			 *
733 			 * VTTBR_EL2.BADDR: Set to zero as EL1&0 stage 2 address
734 			 *  translation is disabled.
735 			 */
736 			write_vttbr_el2(VTTBR_RESET_VAL &
737 				~((VTTBR_VMID_MASK << VTTBR_VMID_SHIFT)
738 				| (VTTBR_BADDR_MASK << VTTBR_BADDR_SHIFT)));
739 
740 			/*
741 			 * Initialise MDCR_EL2, setting all fields rather than
742 			 * relying on hw. Some fields are architecturally
743 			 * UNKNOWN on reset.
744 			 *
745 			 * MDCR_EL2.HLP: Set to one so that event counter
746 			 *  overflow, that is recorded in PMOVSCLR_EL0[0-30],
747 			 *  occurs on the increment that changes
748 			 *  PMEVCNTR<n>_EL0[63] from 1 to 0, when ARMv8.5-PMU is
749 			 *  implemented. This bit is RES0 in versions of the
750 			 *  architecture earlier than ARMv8.5, setting it to 1
751 			 *  doesn't have any effect on them.
752 			 *
753 			 * MDCR_EL2.TTRF: Set to zero so that access to Trace
754 			 *  Filter Control register TRFCR_EL1 at EL1 is not
755 			 *  trapped to EL2. This bit is RES0 in versions of
756 			 *  the architecture earlier than ARMv8.4.
757 			 *
758 			 * MDCR_EL2.HPMD: Set to one so that event counting is
759 			 *  prohibited at EL2. This bit is RES0 in versions of
760 			 *  the architecture earlier than ARMv8.1, setting it
761 			 *  to 1 doesn't have any effect on them.
762 			 *
763 			 * MDCR_EL2.TPMS: Set to zero so that accesses to
764 			 *  Statistical Profiling control registers from EL1
765 			 *  do not trap to EL2. This bit is RES0 when SPE is
766 			 *  not implemented.
767 			 *
768 			 * MDCR_EL2.TDRA: Set to zero so that Non-secure EL0 and
769 			 *  EL1 System register accesses to the Debug ROM
770 			 *  registers are not trapped to EL2.
771 			 *
772 			 * MDCR_EL2.TDOSA: Set to zero so that Non-secure EL1
773 			 *  System register accesses to the powerdown debug
774 			 *  registers are not trapped to EL2.
775 			 *
776 			 * MDCR_EL2.TDA: Set to zero so that System register
777 			 *  accesses to the debug registers do not trap to EL2.
778 			 *
779 			 * MDCR_EL2.TDE: Set to zero so that debug exceptions
780 			 *  are not routed to EL2.
781 			 *
782 			 * MDCR_EL2.HPME: Set to zero to disable EL2 Performance
783 			 *  Monitors.
784 			 *
785 			 * MDCR_EL2.TPM: Set to zero so that Non-secure EL0 and
786 			 *  EL1 accesses to all Performance Monitors registers
787 			 *  are not trapped to EL2.
788 			 *
789 			 * MDCR_EL2.TPMCR: Set to zero so that Non-secure EL0
790 			 *  and EL1 accesses to the PMCR_EL0 or PMCR are not
791 			 *  trapped to EL2.
792 			 *
793 			 * MDCR_EL2.HPMN: Set to value of PMCR_EL0.N which is the
794 			 *  architecturally-defined reset value.
795 			 *
796 			 * MDCR_EL2.E2TB: Set to zero so that the trace Buffer
797 			 *  owning exception level is NS-EL1 and, tracing is
798 			 *  prohibited at NS-EL2. These bits are RES0 when
799 			 *  FEAT_TRBE is not implemented.
800 			 */
801 			mdcr_el2 = ((MDCR_EL2_RESET_VAL | MDCR_EL2_HLP |
802 				     MDCR_EL2_HPMD) |
803 				   ((read_pmcr_el0() & PMCR_EL0_N_BITS)
804 				   >> PMCR_EL0_N_SHIFT)) &
805 				   ~(MDCR_EL2_TTRF | MDCR_EL2_TPMS |
806 				     MDCR_EL2_TDRA_BIT | MDCR_EL2_TDOSA_BIT |
807 				     MDCR_EL2_TDA_BIT | MDCR_EL2_TDE_BIT |
808 				     MDCR_EL2_HPME_BIT | MDCR_EL2_TPM_BIT |
809 				     MDCR_EL2_TPMCR_BIT |
810 				     MDCR_EL2_E2TB(MDCR_EL2_E2TB_EL1));
811 
812 			write_mdcr_el2(mdcr_el2);
813 
814 			/*
815 			 * Initialise HSTR_EL2. All fields are architecturally
816 			 * UNKNOWN on reset.
817 			 *
818 			 * HSTR_EL2.T<n>: Set all these fields to zero so that
819 			 *  Non-secure EL0 or EL1 accesses to System registers
820 			 *  do not trap to EL2.
821 			 */
822 			write_hstr_el2(HSTR_EL2_RESET_VAL & ~(HSTR_EL2_T_MASK));
823 			/*
824 			 * Initialise CNTHP_CTL_EL2. All fields are
825 			 * architecturally UNKNOWN on reset.
826 			 *
827 			 * CNTHP_CTL_EL2:ENABLE: Set to zero to disable the EL2
828 			 *  physical timer and prevent timer interrupts.
829 			 */
830 			write_cnthp_ctl_el2(CNTHP_CTL_RESET_VAL &
831 						~(CNTHP_CTL_ENABLE_BIT));
832 		}
833 		manage_extensions_nonsecure(el2_unused, ctx);
834 	}
835 
836 	cm_el1_sysregs_context_restore(security_state);
837 	cm_set_next_eret_context(security_state);
838 }
839 
840 #if CTX_INCLUDE_EL2_REGS
841 
842 static void el2_sysregs_context_save_fgt(el2_sysregs_t *ctx)
843 {
844 	write_ctx_reg(ctx, CTX_HDFGRTR_EL2, read_hdfgrtr_el2());
845 	if (is_feat_amu_supported()) {
846 		write_ctx_reg(ctx, CTX_HAFGRTR_EL2, read_hafgrtr_el2());
847 	}
848 	write_ctx_reg(ctx, CTX_HDFGWTR_EL2, read_hdfgwtr_el2());
849 	write_ctx_reg(ctx, CTX_HFGITR_EL2, read_hfgitr_el2());
850 	write_ctx_reg(ctx, CTX_HFGRTR_EL2, read_hfgrtr_el2());
851 	write_ctx_reg(ctx, CTX_HFGWTR_EL2, read_hfgwtr_el2());
852 }
853 
854 static void el2_sysregs_context_restore_fgt(el2_sysregs_t *ctx)
855 {
856 	write_hdfgrtr_el2(read_ctx_reg(ctx, CTX_HDFGRTR_EL2));
857 	if (is_feat_amu_supported()) {
858 		write_hafgrtr_el2(read_ctx_reg(ctx, CTX_HAFGRTR_EL2));
859 	}
860 	write_hdfgwtr_el2(read_ctx_reg(ctx, CTX_HDFGWTR_EL2));
861 	write_hfgitr_el2(read_ctx_reg(ctx, CTX_HFGITR_EL2));
862 	write_hfgrtr_el2(read_ctx_reg(ctx, CTX_HFGRTR_EL2));
863 	write_hfgwtr_el2(read_ctx_reg(ctx, CTX_HFGWTR_EL2));
864 }
865 
866 static void el2_sysregs_context_save_mpam(el2_sysregs_t *ctx)
867 {
868 	u_register_t mpam_idr = read_mpamidr_el1();
869 
870 	write_ctx_reg(ctx, CTX_MPAM2_EL2, read_mpam2_el2());
871 
872 	/*
873 	 * The context registers that we intend to save would be part of the
874 	 * PE's system register frame only if MPAMIDR_EL1.HAS_HCR == 1.
875 	 */
876 	if ((mpam_idr & MPAMIDR_HAS_HCR_BIT) == 0U) {
877 		return;
878 	}
879 
880 	/*
881 	 * MPAMHCR_EL2, MPAMVPMV_EL2 and MPAMVPM0_EL2 are always present if
882 	 * MPAMIDR_HAS_HCR_BIT == 1.
883 	 */
884 	write_ctx_reg(ctx, CTX_MPAMHCR_EL2, read_mpamhcr_el2());
885 	write_ctx_reg(ctx, CTX_MPAMVPM0_EL2, read_mpamvpm0_el2());
886 	write_ctx_reg(ctx, CTX_MPAMVPMV_EL2, read_mpamvpmv_el2());
887 
888 	/*
889 	 * The number of MPAMVPM registers is implementation defined, their
890 	 * number is stored in the MPAMIDR_EL1 register.
891 	 */
892 	switch ((mpam_idr >> MPAMIDR_EL1_VPMR_MAX_SHIFT) & MPAMIDR_EL1_VPMR_MAX_MASK) {
893 	case 7:
894 		write_ctx_reg(ctx, CTX_MPAMVPM7_EL2, read_mpamvpm7_el2());
895 		__fallthrough;
896 	case 6:
897 		write_ctx_reg(ctx, CTX_MPAMVPM6_EL2, read_mpamvpm6_el2());
898 		__fallthrough;
899 	case 5:
900 		write_ctx_reg(ctx, CTX_MPAMVPM5_EL2, read_mpamvpm5_el2());
901 		__fallthrough;
902 	case 4:
903 		write_ctx_reg(ctx, CTX_MPAMVPM4_EL2, read_mpamvpm4_el2());
904 		__fallthrough;
905 	case 3:
906 		write_ctx_reg(ctx, CTX_MPAMVPM3_EL2, read_mpamvpm3_el2());
907 		__fallthrough;
908 	case 2:
909 		write_ctx_reg(ctx, CTX_MPAMVPM2_EL2, read_mpamvpm2_el2());
910 		__fallthrough;
911 	case 1:
912 		write_ctx_reg(ctx, CTX_MPAMVPM1_EL2, read_mpamvpm1_el2());
913 		break;
914 	}
915 }
916 
917 static void el2_sysregs_context_restore_mpam(el2_sysregs_t *ctx)
918 {
919 	u_register_t mpam_idr = read_mpamidr_el1();
920 
921 	write_mpam2_el2(read_ctx_reg(ctx, CTX_MPAM2_EL2));
922 
923 	if ((mpam_idr & MPAMIDR_HAS_HCR_BIT) == 0U) {
924 		return;
925 	}
926 
927 	write_mpamhcr_el2(read_ctx_reg(ctx, CTX_MPAMHCR_EL2));
928 	write_mpamvpm0_el2(read_ctx_reg(ctx, CTX_MPAMVPM0_EL2));
929 	write_mpamvpmv_el2(read_ctx_reg(ctx, CTX_MPAMVPMV_EL2));
930 
931 	switch ((mpam_idr >> MPAMIDR_EL1_VPMR_MAX_SHIFT) & MPAMIDR_EL1_VPMR_MAX_MASK) {
932 	case 7:
933 		write_mpamvpm7_el2(read_ctx_reg(ctx, CTX_MPAMVPM7_EL2));
934 		__fallthrough;
935 	case 6:
936 		write_mpamvpm6_el2(read_ctx_reg(ctx, CTX_MPAMVPM6_EL2));
937 		__fallthrough;
938 	case 5:
939 		write_mpamvpm5_el2(read_ctx_reg(ctx, CTX_MPAMVPM5_EL2));
940 		__fallthrough;
941 	case 4:
942 		write_mpamvpm4_el2(read_ctx_reg(ctx, CTX_MPAMVPM4_EL2));
943 		__fallthrough;
944 	case 3:
945 		write_mpamvpm3_el2(read_ctx_reg(ctx, CTX_MPAMVPM3_EL2));
946 		__fallthrough;
947 	case 2:
948 		write_mpamvpm2_el2(read_ctx_reg(ctx, CTX_MPAMVPM2_EL2));
949 		__fallthrough;
950 	case 1:
951 		write_mpamvpm1_el2(read_ctx_reg(ctx, CTX_MPAMVPM1_EL2));
952 		break;
953 	}
954 }
955 
956 /*******************************************************************************
957  * Save EL2 sysreg context
958  ******************************************************************************/
959 void cm_el2_sysregs_context_save(uint32_t security_state)
960 {
961 	u_register_t scr_el3 = read_scr();
962 
963 	/*
964 	 * Always save the non-secure and realm EL2 context, only save the
965 	 * S-EL2 context if S-EL2 is enabled.
966 	 */
967 	if ((security_state != SECURE) ||
968 	    ((security_state == SECURE) && ((scr_el3 & SCR_EEL2_BIT) != 0U))) {
969 		cpu_context_t *ctx;
970 		el2_sysregs_t *el2_sysregs_ctx;
971 
972 		ctx = cm_get_context(security_state);
973 		assert(ctx != NULL);
974 
975 		el2_sysregs_ctx = get_el2_sysregs_ctx(ctx);
976 
977 		el2_sysregs_context_save_common(el2_sysregs_ctx);
978 #if CTX_INCLUDE_MTE_REGS
979 		el2_sysregs_context_save_mte(el2_sysregs_ctx);
980 #endif
981 		if (is_feat_mpam_supported()) {
982 			el2_sysregs_context_save_mpam(el2_sysregs_ctx);
983 		}
984 
985 		if (is_feat_fgt_supported()) {
986 			el2_sysregs_context_save_fgt(el2_sysregs_ctx);
987 		}
988 
989 		if (is_feat_ecv_v2_supported()) {
990 			write_ctx_reg(el2_sysregs_ctx, CTX_CNTPOFF_EL2,
991 				      read_cntpoff_el2());
992 		}
993 
994 		if (is_feat_vhe_supported()) {
995 			write_ctx_reg(el2_sysregs_ctx, CTX_CONTEXTIDR_EL2,
996 				      read_contextidr_el2());
997 			write_ctx_reg(el2_sysregs_ctx, CTX_TTBR1_EL2,
998 				      read_ttbr1_el2());
999 		}
1000 #if RAS_EXTENSION
1001 		el2_sysregs_context_save_ras(el2_sysregs_ctx);
1002 #endif
1003 
1004 		if (is_feat_nv2_supported()) {
1005 			write_ctx_reg(el2_sysregs_ctx, CTX_VNCR_EL2,
1006 				      read_vncr_el2());
1007 		}
1008 
1009 		if (is_feat_trf_supported()) {
1010 			write_ctx_reg(el2_sysregs_ctx, CTX_TRFCR_EL2, read_trfcr_el2());
1011 		}
1012 
1013 		if (is_feat_csv2_2_supported()) {
1014 			write_ctx_reg(el2_sysregs_ctx, CTX_SCXTNUM_EL2,
1015 				      read_scxtnum_el2());
1016 		}
1017 
1018 		if (is_feat_hcx_supported()) {
1019 			write_ctx_reg(el2_sysregs_ctx, CTX_HCRX_EL2, read_hcrx_el2());
1020 		}
1021 		if (is_feat_tcr2_supported()) {
1022 			write_ctx_reg(el2_sysregs_ctx, CTX_TCR2_EL2, read_tcr2_el2());
1023 		}
1024 	}
1025 }
1026 
1027 /*******************************************************************************
1028  * Restore EL2 sysreg context
1029  ******************************************************************************/
1030 void cm_el2_sysregs_context_restore(uint32_t security_state)
1031 {
1032 	u_register_t scr_el3 = read_scr();
1033 
1034 	/*
1035 	 * Always restore the non-secure and realm EL2 context, only restore the
1036 	 * S-EL2 context if S-EL2 is enabled.
1037 	 */
1038 	if ((security_state != SECURE) ||
1039 	    ((security_state == SECURE) && ((scr_el3 & SCR_EEL2_BIT) != 0U))) {
1040 		cpu_context_t *ctx;
1041 		el2_sysregs_t *el2_sysregs_ctx;
1042 
1043 		ctx = cm_get_context(security_state);
1044 		assert(ctx != NULL);
1045 
1046 		el2_sysregs_ctx = get_el2_sysregs_ctx(ctx);
1047 
1048 		el2_sysregs_context_restore_common(el2_sysregs_ctx);
1049 #if CTX_INCLUDE_MTE_REGS
1050 		el2_sysregs_context_restore_mte(el2_sysregs_ctx);
1051 #endif
1052 		if (is_feat_mpam_supported()) {
1053 			el2_sysregs_context_restore_mpam(el2_sysregs_ctx);
1054 		}
1055 
1056 		if (is_feat_fgt_supported()) {
1057 			el2_sysregs_context_restore_fgt(el2_sysregs_ctx);
1058 		}
1059 
1060 		if (is_feat_ecv_v2_supported()) {
1061 			write_cntpoff_el2(read_ctx_reg(el2_sysregs_ctx,
1062 						       CTX_CNTPOFF_EL2));
1063 		}
1064 
1065 		if (is_feat_vhe_supported()) {
1066 			write_contextidr_el2(read_ctx_reg(el2_sysregs_ctx, CTX_CONTEXTIDR_EL2));
1067 			write_ttbr1_el2(read_ctx_reg(el2_sysregs_ctx, CTX_TTBR1_EL2));
1068 		}
1069 #if RAS_EXTENSION
1070 		el2_sysregs_context_restore_ras(el2_sysregs_ctx);
1071 #endif
1072 
1073 		if (is_feat_nv2_supported()) {
1074 			write_vncr_el2(read_ctx_reg(el2_sysregs_ctx, CTX_VNCR_EL2));
1075 		}
1076 		if (is_feat_trf_supported()) {
1077 			write_trfcr_el2(read_ctx_reg(el2_sysregs_ctx, CTX_TRFCR_EL2));
1078 		}
1079 
1080 		if (is_feat_csv2_2_supported()) {
1081 			write_scxtnum_el2(read_ctx_reg(el2_sysregs_ctx,
1082 						       CTX_SCXTNUM_EL2));
1083 		}
1084 
1085 		if (is_feat_hcx_supported()) {
1086 			write_hcrx_el2(read_ctx_reg(el2_sysregs_ctx, CTX_HCRX_EL2));
1087 		}
1088 		if (is_feat_tcr2_supported()) {
1089 			write_tcr2_el2(read_ctx_reg(el2_sysregs_ctx, CTX_TCR2_EL2));
1090 		}
1091 	}
1092 }
1093 #endif /* CTX_INCLUDE_EL2_REGS */
1094 
1095 /*******************************************************************************
1096  * This function is used to exit to Non-secure world. If CTX_INCLUDE_EL2_REGS
1097  * is enabled, it restores EL1 and EL2 sysreg contexts instead of directly
1098  * updating EL1 and EL2 registers. Otherwise, it calls the generic
1099  * cm_prepare_el3_exit function.
1100  ******************************************************************************/
1101 void cm_prepare_el3_exit_ns(void)
1102 {
1103 #if CTX_INCLUDE_EL2_REGS
1104 	cpu_context_t *ctx = cm_get_context(NON_SECURE);
1105 	assert(ctx != NULL);
1106 
1107 	/* Assert that EL2 is used. */
1108 #if ENABLE_ASSERTIONS
1109 	el3_state_t *state = get_el3state_ctx(ctx);
1110 	u_register_t scr_el3 = read_ctx_reg(state, CTX_SCR_EL3);
1111 #endif
1112 	assert(((scr_el3 & SCR_HCE_BIT) != 0UL) &&
1113 			(el_implemented(2U) != EL_IMPL_NONE));
1114 
1115 	/*
1116 	 * Currently some extensions are configured using
1117 	 * direct register updates. Therefore, do this here
1118 	 * instead of when setting up context.
1119 	 */
1120 	manage_extensions_nonsecure(0, ctx);
1121 
1122 	/*
1123 	 * Set the NS bit to be able to access the ICC_SRE_EL2
1124 	 * register when restoring context.
1125 	 */
1126 	write_scr_el3(read_scr_el3() | SCR_NS_BIT);
1127 
1128 	/*
1129 	 * Ensure the NS bit change is committed before the EL2/EL1
1130 	 * state restoration.
1131 	 */
1132 	isb();
1133 
1134 	/* Restore EL2 and EL1 sysreg contexts */
1135 	cm_el2_sysregs_context_restore(NON_SECURE);
1136 	cm_el1_sysregs_context_restore(NON_SECURE);
1137 	cm_set_next_eret_context(NON_SECURE);
1138 #else
1139 	cm_prepare_el3_exit(NON_SECURE);
1140 #endif /* CTX_INCLUDE_EL2_REGS */
1141 }
1142 
1143 /*******************************************************************************
1144  * The next four functions are used by runtime services to save and restore
1145  * EL1 context on the 'cpu_context' structure for the specified security
1146  * state.
1147  ******************************************************************************/
1148 void cm_el1_sysregs_context_save(uint32_t security_state)
1149 {
1150 	cpu_context_t *ctx;
1151 
1152 	ctx = cm_get_context(security_state);
1153 	assert(ctx != NULL);
1154 
1155 	el1_sysregs_context_save(get_el1_sysregs_ctx(ctx));
1156 
1157 #if IMAGE_BL31
1158 	if (security_state == SECURE)
1159 		PUBLISH_EVENT(cm_exited_secure_world);
1160 	else
1161 		PUBLISH_EVENT(cm_exited_normal_world);
1162 #endif
1163 }
1164 
1165 void cm_el1_sysregs_context_restore(uint32_t security_state)
1166 {
1167 	cpu_context_t *ctx;
1168 
1169 	ctx = cm_get_context(security_state);
1170 	assert(ctx != NULL);
1171 
1172 	el1_sysregs_context_restore(get_el1_sysregs_ctx(ctx));
1173 
1174 #if IMAGE_BL31
1175 	if (security_state == SECURE)
1176 		PUBLISH_EVENT(cm_entering_secure_world);
1177 	else
1178 		PUBLISH_EVENT(cm_entering_normal_world);
1179 #endif
1180 }
1181 
1182 /*******************************************************************************
1183  * This function populates ELR_EL3 member of 'cpu_context' pertaining to the
1184  * given security state with the given entrypoint
1185  ******************************************************************************/
1186 void cm_set_elr_el3(uint32_t security_state, uintptr_t entrypoint)
1187 {
1188 	cpu_context_t *ctx;
1189 	el3_state_t *state;
1190 
1191 	ctx = cm_get_context(security_state);
1192 	assert(ctx != NULL);
1193 
1194 	/* Populate EL3 state so that ERET jumps to the correct entry */
1195 	state = get_el3state_ctx(ctx);
1196 	write_ctx_reg(state, CTX_ELR_EL3, entrypoint);
1197 }
1198 
1199 /*******************************************************************************
1200  * This function populates ELR_EL3 and SPSR_EL3 members of 'cpu_context'
1201  * pertaining to the given security state
1202  ******************************************************************************/
1203 void cm_set_elr_spsr_el3(uint32_t security_state,
1204 			uintptr_t entrypoint, uint32_t spsr)
1205 {
1206 	cpu_context_t *ctx;
1207 	el3_state_t *state;
1208 
1209 	ctx = cm_get_context(security_state);
1210 	assert(ctx != NULL);
1211 
1212 	/* Populate EL3 state so that ERET jumps to the correct entry */
1213 	state = get_el3state_ctx(ctx);
1214 	write_ctx_reg(state, CTX_ELR_EL3, entrypoint);
1215 	write_ctx_reg(state, CTX_SPSR_EL3, spsr);
1216 }
1217 
1218 /*******************************************************************************
1219  * This function updates a single bit in the SCR_EL3 member of the 'cpu_context'
1220  * pertaining to the given security state using the value and bit position
1221  * specified in the parameters. It preserves all other bits.
1222  ******************************************************************************/
1223 void cm_write_scr_el3_bit(uint32_t security_state,
1224 			  uint32_t bit_pos,
1225 			  uint32_t value)
1226 {
1227 	cpu_context_t *ctx;
1228 	el3_state_t *state;
1229 	u_register_t scr_el3;
1230 
1231 	ctx = cm_get_context(security_state);
1232 	assert(ctx != NULL);
1233 
1234 	/* Ensure that the bit position is a valid one */
1235 	assert(((1UL << bit_pos) & SCR_VALID_BIT_MASK) != 0U);
1236 
1237 	/* Ensure that the 'value' is only a bit wide */
1238 	assert(value <= 1U);
1239 
1240 	/*
1241 	 * Get the SCR_EL3 value from the cpu context, clear the desired bit
1242 	 * and set it to its new value.
1243 	 */
1244 	state = get_el3state_ctx(ctx);
1245 	scr_el3 = read_ctx_reg(state, CTX_SCR_EL3);
1246 	scr_el3 &= ~(1UL << bit_pos);
1247 	scr_el3 |= (u_register_t)value << bit_pos;
1248 	write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
1249 }
1250 
1251 /*******************************************************************************
1252  * This function retrieves SCR_EL3 member of 'cpu_context' pertaining to the
1253  * given security state.
1254  ******************************************************************************/
1255 u_register_t cm_get_scr_el3(uint32_t security_state)
1256 {
1257 	cpu_context_t *ctx;
1258 	el3_state_t *state;
1259 
1260 	ctx = cm_get_context(security_state);
1261 	assert(ctx != NULL);
1262 
1263 	/* Populate EL3 state so that ERET jumps to the correct entry */
1264 	state = get_el3state_ctx(ctx);
1265 	return read_ctx_reg(state, CTX_SCR_EL3);
1266 }
1267 
1268 /*******************************************************************************
1269  * This function is used to program the context that's used for exception
1270  * return. This initializes the SP_EL3 to a pointer to a 'cpu_context' set for
1271  * the required security state
1272  ******************************************************************************/
1273 void cm_set_next_eret_context(uint32_t security_state)
1274 {
1275 	cpu_context_t *ctx;
1276 
1277 	ctx = cm_get_context(security_state);
1278 	assert(ctx != NULL);
1279 
1280 	cm_set_next_context(ctx);
1281 }
1282