1/*
2 * Copyright (c) 2015-2022, Arm Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7#ifndef EL3_COMMON_MACROS_S
8#define EL3_COMMON_MACROS_S
9
10#include <arch.h>
11#include <asm_macros.S>
12#include <assert_macros.S>
13#include <context.h>
14#include <lib/xlat_tables/xlat_tables_defs.h>
15
16	/*
17	 * Helper macro to initialise EL3 registers we care about.
18	 */
19	.macro el3_arch_init_common
20	/* ---------------------------------------------------------------------
21	 * SCTLR_EL3 has already been initialised - read current value before
22	 * modifying.
23	 *
24	 * SCTLR_EL3.I: Enable the instruction cache.
25	 *
26	 * SCTLR_EL3.SA: Enable Stack Alignment check. A SP alignment fault
27	 *  exception is generated if a load or store instruction executed at
28	 *  EL3 uses the SP as the base address and the SP is not aligned to a
29	 *  16-byte boundary.
30	 *
31	 * SCTLR_EL3.A: Enable Alignment fault checking. All instructions that
32	 *  load or store one or more registers have an alignment check that the
33	 *  address being accessed is aligned to the size of the data element(s)
34	 *  being accessed.
35	 * ---------------------------------------------------------------------
36	 */
37	mov	x1, #(SCTLR_I_BIT | SCTLR_A_BIT | SCTLR_SA_BIT)
38	mrs	x0, sctlr_el3
39	orr	x0, x0, x1
40	msr	sctlr_el3, x0
41	isb
42
43#ifdef IMAGE_BL31
44	/* ---------------------------------------------------------------------
45	 * Initialise the per-cpu cache pointer to the CPU.
46	 * This is done early to enable crash reporting to have access to crash
47	 * stack. Since crash reporting depends on cpu_data to report the
48	 * unhandled exception, not doing so can lead to recursive exceptions
49	 * due to a NULL TPIDR_EL3.
50	 * ---------------------------------------------------------------------
51	 */
52	bl	init_cpu_data_ptr
53#endif /* IMAGE_BL31 */
54
55	/* ---------------------------------------------------------------------
56	 * Initialise SCR_EL3, setting all fields rather than relying on hw.
57	 * All fields are architecturally UNKNOWN on reset. The following fields
58	 * do not change during the TF lifetime. The remaining fields are set to
59	 * zero here but are updated ahead of transitioning to a lower EL in the
60	 * function cm_init_context_common().
61	 *
62	 * SCR_EL3.TWE: Set to zero so that execution of WFE instructions at
63	 *  EL2, EL1 and EL0 are not trapped to EL3.
64	 *
65	 * SCR_EL3.TWI: Set to zero so that execution of WFI instructions at
66	 *  EL2, EL1 and EL0 are not trapped to EL3.
67	 *
68	 * SCR_EL3.SIF: Set to one to disable instruction fetches from
69	 *  Non-secure memory.
70	 *
71	 * SCR_EL3.SMD: Set to zero to enable SMC calls at EL1 and above, from
72	 *  both Security states and both Execution states.
73	 *
74	 * SCR_EL3.EA: Set to one to route External Aborts and SError Interrupts
75	 *  to EL3 when executing at any EL.
76	 *
77	 * SCR_EL3.{API,APK}: For Armv8.3 pointer authentication feature,
78	 * disable traps to EL3 when accessing key registers or using pointer
79	 * authentication instructions from lower ELs.
80	 * ---------------------------------------------------------------------
81	 */
82	mov_imm	x0, ((SCR_RESET_VAL | SCR_EA_BIT | SCR_SIF_BIT) \
83			& ~(SCR_TWE_BIT | SCR_TWI_BIT | SCR_SMD_BIT))
84#if CTX_INCLUDE_PAUTH_REGS
85	/*
86	 * If the pointer authentication registers are saved during world
87	 * switches, enable pointer authentication everywhere, as it is safe to
88	 * do so.
89	 */
90	orr	x0, x0, #(SCR_API_BIT | SCR_APK_BIT)
91#endif
92#if ENABLE_RME
93	/*
94	 * TODO: Settting the EEL2 bit to allow EL3 access to secure only registers
95	 * in context management. This will need to be refactored.
96	 */
97	orr	x0, x0, #SCR_EEL2_BIT
98#endif
99	msr	scr_el3, x0
100
101	/* ---------------------------------------------------------------------
102	 * Initialise MDCR_EL3, setting all fields rather than relying on hw.
103	 * Some fields are architecturally UNKNOWN on reset.
104	 *
105	 * MDCR_EL3.SDD: Set to one to disable AArch64 Secure self-hosted debug.
106	 *  Debug exceptions, other than Breakpoint Instruction exceptions, are
107	 *  disabled from all ELs in Secure state.
108	 *
109	 * MDCR_EL3.SPD32: Set to 0b10 to disable AArch32 Secure self-hosted
110	 *  privileged debug from S-EL1.
111	 *
112	 * MDCR_EL3.TDOSA: Set to zero so that EL2 and EL2 System register
113	 *  access to the powerdown debug registers do not trap to EL3.
114	 *
115	 * MDCR_EL3.TDA: Set to zero to allow EL0, EL1 and EL2 access to the
116	 *  debug registers, other than those registers that are controlled by
117	 *  MDCR_EL3.TDOSA.
118	 *
119	 * MDCR_EL3.TPM: Set to zero so that EL0, EL1, and EL2 System register
120	 *  accesses to all Performance Monitors registers do not trap to EL3.
121	 *
122	 * MDCR_EL3.SCCD: Set to one so that cycle counting by PMCCNTR_EL0 is
123	 *  prohibited in Secure state. This bit is RES0 in versions of the
124	 *  architecture with FEAT_PMUv3p5 not implemented, setting it to 1
125	 *  doesn't have any effect on them.
126	 *
127	 * MDCR_EL3.MCCD: Set to one so that cycle counting by PMCCNTR_EL0 is
128	 *  prohibited in EL3. This bit is RES0 in versions of the
129	 *  architecture with FEAT_PMUv3p7 not implemented, setting it to 1
130	 *  doesn't have any effect on them.
131	 *
132	 * MDCR_EL3.SPME: Set to zero so that event counting by the programmable
133	 *  counters PMEVCNTR<n>_EL0 is prohibited in Secure state. If ARMv8.2
134	 *  Debug is not implemented this bit does not have any effect on the
135	 *  counters unless there is support for the implementation defined
136	 *  authentication interface ExternalSecureNoninvasiveDebugEnabled().
137	 *
138	 * MDCR_EL3.NSTB, MDCR_EL3.NSTBE: Set to zero so that Trace Buffer
139	 *  owning security state is Secure state. If FEAT_TRBE is implemented,
140	 *  accesses to Trace Buffer control registers at EL2 and EL1 in any
141	 *  security state generates trap exceptions to EL3.
142	 *  If FEAT_TRBE is not implemented, these bits are RES0.
143	 *
144	 * MDCR_EL3.TTRF: Set to one so that access to trace filter control
145	 *  registers in non-monitor mode generate EL3 trap exception,
146	 *  unless the access generates a higher priority exception when trace
147	 *  filter control(FEAT_TRF) is implemented.
148	 *  When FEAT_TRF is not implemented, this bit is RES0.
149	 * ---------------------------------------------------------------------
150	 */
151	mov_imm	x0, ((MDCR_EL3_RESET_VAL | MDCR_SDD_BIT | \
152		      MDCR_SPD32(MDCR_SPD32_DISABLE) | MDCR_SCCD_BIT | \
153		      MDCR_MCCD_BIT) & ~(MDCR_SPME_BIT | MDCR_TDOSA_BIT | \
154		      MDCR_TDA_BIT | MDCR_TPM_BIT | MDCR_NSTB(MDCR_NSTB_EL1) | \
155		      MDCR_NSTBE | MDCR_TTRF_BIT))
156
157	mrs	x1, id_aa64dfr0_el1
158	ubfx	x1, x1, #ID_AA64DFR0_TRACEFILT_SHIFT, #ID_AA64DFR0_TRACEFILT_LENGTH
159	cbz	x1, 1f
160	orr	x0, x0, #MDCR_TTRF_BIT
1611:
162	msr	mdcr_el3, x0
163
164	/* ---------------------------------------------------------------------
165	 * Initialise PMCR_EL0 setting all fields rather than relying
166	 * on hw. Some fields are architecturally UNKNOWN on reset.
167	 *
168	 * PMCR_EL0.LP: Set to one so that event counter overflow, that
169	 *  is recorded in PMOVSCLR_EL0[0-30], occurs on the increment
170	 *  that changes PMEVCNTR<n>_EL0[63] from 1 to 0, when ARMv8.5-PMU
171	 *  is implemented. This bit is RES0 in versions of the architecture
172	 *  earlier than ARMv8.5, setting it to 1 doesn't have any effect
173	 *  on them.
174	 *
175	 * PMCR_EL0.LC: Set to one so that cycle counter overflow, that
176	 *  is recorded in PMOVSCLR_EL0[31], occurs on the increment
177	 *  that changes PMCCNTR_EL0[63] from 1 to 0.
178	 *
179	 * PMCR_EL0.DP: Set to one so that the cycle counter,
180	 *  PMCCNTR_EL0 does not count when event counting is prohibited.
181	 *
182	 * PMCR_EL0.X: Set to zero to disable export of events.
183	 *
184	 * PMCR_EL0.D: Set to zero so that, when enabled, PMCCNTR_EL0
185	 *  counts on every clock cycle.
186	 * ---------------------------------------------------------------------
187	 */
188	mov_imm	x0, ((PMCR_EL0_RESET_VAL | PMCR_EL0_LP_BIT | \
189		      PMCR_EL0_LC_BIT | PMCR_EL0_DP_BIT) & \
190		    ~(PMCR_EL0_X_BIT | PMCR_EL0_D_BIT))
191
192	msr	pmcr_el0, x0
193
194	/* ---------------------------------------------------------------------
195	 * Enable External Aborts and SError Interrupts now that the exception
196	 * vectors have been setup.
197	 * ---------------------------------------------------------------------
198	 */
199	msr	daifclr, #DAIF_ABT_BIT
200
201	/* ---------------------------------------------------------------------
202	 * Initialise CPTR_EL3, setting all fields rather than relying on hw.
203	 * All fields are architecturally UNKNOWN on reset.
204	 *
205	 * CPTR_EL3.TCPAC: Set to zero so that any accesses to CPACR_EL1,
206	 *  CPTR_EL2, CPACR, or HCPTR do not trap to EL3.
207	 *
208	 * CPTR_EL3.TTA: Set to one so that accesses to the trace system
209	 *  registers trap to EL3 from all exception levels and security
210	 *  states when system register trace is implemented.
211	 *  When system register trace is not implemented, this bit is RES0 and
212	 *  hence set to zero.
213	 *
214	 * CPTR_EL3.TTA: Set to zero so that System register accesses to the
215	 *  trace registers do not trap to EL3.
216	 *
217	 * CPTR_EL3.TFP: Set to zero so that accesses to the V- or Z- registers
218	 *  by Advanced SIMD, floating-point or SVE instructions (if implemented)
219	 *  do not trap to EL3.
220	 *
221	 * CPTR_EL3.TAM: Set to one so that Activity Monitor access is
222	 *  trapped to EL3 by default.
223	 *
224	 * CPTR_EL3.EZ: Set to zero so that all SVE functionality is trapped
225	 *  to EL3 by default.
226	 *
227	 * CPTR_EL3.ESM: Set to zero so that all SME functionality is trapped
228	 *  to EL3 by default.
229	 */
230
231	mov_imm x0, (CPTR_EL3_RESET_VAL & ~(TCPAC_BIT | TTA_BIT | TFP_BIT))
232	mrs	x1, id_aa64dfr0_el1
233	ubfx	x1, x1, #ID_AA64DFR0_TRACEVER_SHIFT, #ID_AA64DFR0_TRACEVER_LENGTH
234	cbz	x1, 1f
235	orr	x0, x0, #TTA_BIT
2361:
237	msr	cptr_el3, x0
238
239	/*
240	 * If Data Independent Timing (DIT) functionality is implemented,
241	 * always enable DIT in EL3.
242	 * First assert that the FEAT_DIT build flag matches the feature id
243	 * register value for DIT.
244	 */
245#if ENABLE_FEAT_DIT
246#if ENABLE_ASSERTIONS
247	mrs	x0, id_aa64pfr0_el1
248	ubfx	x0, x0, #ID_AA64PFR0_DIT_SHIFT, #ID_AA64PFR0_DIT_LENGTH
249	cmp	x0, #ID_AA64PFR0_DIT_SUPPORTED
250	ASM_ASSERT(eq)
251#endif /* ENABLE_ASSERTIONS */
252	mov	x0, #DIT_BIT
253	msr	DIT, x0
254#endif
255	.endm
256
257/* -----------------------------------------------------------------------------
258 * This is the super set of actions that need to be performed during a cold boot
259 * or a warm boot in EL3. This code is shared by BL1 and BL31.
260 *
261 * This macro will always perform reset handling, architectural initialisations
262 * and stack setup. The rest of the actions are optional because they might not
263 * be needed, depending on the context in which this macro is called. This is
264 * why this macro is parameterised ; each parameter allows to enable/disable
265 * some actions.
266 *
267 *  _init_sctlr:
268 *	Whether the macro needs to initialise SCTLR_EL3, including configuring
269 *      the endianness of data accesses.
270 *
271 *  _warm_boot_mailbox:
272 *	Whether the macro needs to detect the type of boot (cold/warm). The
273 *	detection is based on the platform entrypoint address : if it is zero
274 *	then it is a cold boot, otherwise it is a warm boot. In the latter case,
275 *	this macro jumps on the platform entrypoint address.
276 *
277 *  _secondary_cold_boot:
278 *	Whether the macro needs to identify the CPU that is calling it: primary
279 *	CPU or secondary CPU. The primary CPU will be allowed to carry on with
280 *	the platform initialisations, while the secondaries will be put in a
281 *	platform-specific state in the meantime.
282 *
283 *	If the caller knows this macro will only be called by the primary CPU
284 *	then this parameter can be defined to 0 to skip this step.
285 *
286 * _init_memory:
287 *	Whether the macro needs to initialise the memory.
288 *
289 * _init_c_runtime:
290 *	Whether the macro needs to initialise the C runtime environment.
291 *
292 * _exception_vectors:
293 *	Address of the exception vectors to program in the VBAR_EL3 register.
294 *
295 * _pie_fixup_size:
296 *	Size of memory region to fixup Global Descriptor Table (GDT).
297 *
298 *	A non-zero value is expected when firmware needs GDT to be fixed-up.
299 *
300 * -----------------------------------------------------------------------------
301 */
302	.macro el3_entrypoint_common					\
303		_init_sctlr, _warm_boot_mailbox, _secondary_cold_boot,	\
304		_init_memory, _init_c_runtime, _exception_vectors,	\
305		_pie_fixup_size
306
307	.if \_init_sctlr
308		/* -------------------------------------------------------------
309		 * This is the initialisation of SCTLR_EL3 and so must ensure
310		 * that all fields are explicitly set rather than relying on hw.
311		 * Some fields reset to an IMPLEMENTATION DEFINED value and
312		 * others are architecturally UNKNOWN on reset.
313		 *
314		 * SCTLR.EE: Set the CPU endianness before doing anything that
315		 *  might involve memory reads or writes. Set to zero to select
316		 *  Little Endian.
317		 *
318		 * SCTLR_EL3.WXN: For the EL3 translation regime, this field can
319		 *  force all memory regions that are writeable to be treated as
320		 *  XN (Execute-never). Set to zero so that this control has no
321		 *  effect on memory access permissions.
322		 *
323		 * SCTLR_EL3.SA: Set to zero to disable Stack Alignment check.
324		 *
325		 * SCTLR_EL3.A: Set to zero to disable Alignment fault checking.
326		 *
327		 * SCTLR.DSSBS: Set to zero to disable speculation store bypass
328		 *  safe behaviour upon exception entry to EL3.
329		 * -------------------------------------------------------------
330		 */
331		mov_imm	x0, (SCTLR_RESET_VAL & ~(SCTLR_EE_BIT | SCTLR_WXN_BIT \
332				| SCTLR_SA_BIT | SCTLR_A_BIT | SCTLR_DSSBS_BIT))
333		msr	sctlr_el3, x0
334		isb
335	.endif /* _init_sctlr */
336
337#if DISABLE_MTPMU
338		bl	mtpmu_disable
339#endif
340
341	.if \_warm_boot_mailbox
342		/* -------------------------------------------------------------
343		 * This code will be executed for both warm and cold resets.
344		 * Now is the time to distinguish between the two.
345		 * Query the platform entrypoint address and if it is not zero
346		 * then it means it is a warm boot so jump to this address.
347		 * -------------------------------------------------------------
348		 */
349		bl	plat_get_my_entrypoint
350		cbz	x0, do_cold_boot
351		br	x0
352
353	do_cold_boot:
354	.endif /* _warm_boot_mailbox */
355
356	.if \_pie_fixup_size
357#if ENABLE_PIE
358		/*
359		 * ------------------------------------------------------------
360		 * If PIE is enabled fixup the Global descriptor Table only
361		 * once during primary core cold boot path.
362		 *
363		 * Compile time base address, required for fixup, is calculated
364		 * using "pie_fixup" label present within first page.
365		 * ------------------------------------------------------------
366		 */
367	pie_fixup:
368		ldr	x0, =pie_fixup
369		and	x0, x0, #~(PAGE_SIZE_MASK)
370		mov_imm	x1, \_pie_fixup_size
371		add	x1, x1, x0
372		bl	fixup_gdt_reloc
373#endif /* ENABLE_PIE */
374	.endif /* _pie_fixup_size */
375
376	/* ---------------------------------------------------------------------
377	 * Set the exception vectors.
378	 * ---------------------------------------------------------------------
379	 */
380	adr	x0, \_exception_vectors
381	msr	vbar_el3, x0
382	isb
383
384#if !(defined(IMAGE_BL2) && ENABLE_RME)
385	/* ---------------------------------------------------------------------
386	 * It is a cold boot.
387	 * Perform any processor specific actions upon reset e.g. cache, TLB
388	 * invalidations etc.
389	 * ---------------------------------------------------------------------
390	 */
391	bl	reset_handler
392#endif
393
394	el3_arch_init_common
395
396	.if \_secondary_cold_boot
397		/* -------------------------------------------------------------
398		 * Check if this is a primary or secondary CPU cold boot.
399		 * The primary CPU will set up the platform while the
400		 * secondaries are placed in a platform-specific state until the
401		 * primary CPU performs the necessary actions to bring them out
402		 * of that state and allows entry into the OS.
403		 * -------------------------------------------------------------
404		 */
405		bl	plat_is_my_cpu_primary
406		cbnz	w0, do_primary_cold_boot
407
408		/* This is a cold boot on a secondary CPU */
409		bl	plat_secondary_cold_boot_setup
410		/* plat_secondary_cold_boot_setup() is not supposed to return */
411		bl	el3_panic
412
413	do_primary_cold_boot:
414	.endif /* _secondary_cold_boot */
415
416	/* ---------------------------------------------------------------------
417	 * Initialize memory now. Secondary CPU initialization won't get to this
418	 * point.
419	 * ---------------------------------------------------------------------
420	 */
421
422	.if \_init_memory
423		bl	platform_mem_init
424	.endif /* _init_memory */
425
426	/* ---------------------------------------------------------------------
427	 * Init C runtime environment:
428	 *   - Zero-initialise the NOBITS sections. There are 2 of them:
429	 *       - the .bss section;
430	 *       - the coherent memory section (if any).
431	 *   - Relocate the data section from ROM to RAM, if required.
432	 * ---------------------------------------------------------------------
433	 */
434	.if \_init_c_runtime
435#if defined(IMAGE_BL31) || (defined(IMAGE_BL2) && \
436	((BL2_AT_EL3 && BL2_INV_DCACHE) || ENABLE_RME))
437		/* -------------------------------------------------------------
438		 * Invalidate the RW memory used by the BL31 image. This
439		 * includes the data and NOBITS sections. This is done to
440		 * safeguard against possible corruption of this memory by
441		 * dirty cache lines in a system cache as a result of use by
442		 * an earlier boot loader stage. If PIE is enabled however,
443		 * RO sections including the GOT may be modified during
444                 * pie fixup. Therefore, to be on the safe side, invalidate
445		 * the entire image region if PIE is enabled.
446		 * -------------------------------------------------------------
447		 */
448#if ENABLE_PIE
449#if SEPARATE_CODE_AND_RODATA
450		adrp	x0, __TEXT_START__
451		add	x0, x0, :lo12:__TEXT_START__
452#else
453		adrp	x0, __RO_START__
454		add	x0, x0, :lo12:__RO_START__
455#endif /* SEPARATE_CODE_AND_RODATA */
456#else
457		adrp	x0, __RW_START__
458		add	x0, x0, :lo12:__RW_START__
459#endif /* ENABLE_PIE */
460		adrp	x1, __RW_END__
461		add	x1, x1, :lo12:__RW_END__
462		sub	x1, x1, x0
463		bl	inv_dcache_range
464#if defined(IMAGE_BL31) && SEPARATE_NOBITS_REGION
465		adrp	x0, __NOBITS_START__
466		add	x0, x0, :lo12:__NOBITS_START__
467		adrp	x1, __NOBITS_END__
468		add	x1, x1, :lo12:__NOBITS_END__
469		sub	x1, x1, x0
470		bl	inv_dcache_range
471#endif
472#if defined(IMAGE_BL2) && SEPARATE_BL2_NOLOAD_REGION
473		adrp	x0, __BL2_NOLOAD_START__
474		add	x0, x0, :lo12:__BL2_NOLOAD_START__
475		adrp	x1, __BL2_NOLOAD_END__
476		add	x1, x1, :lo12:__BL2_NOLOAD_END__
477		sub	x1, x1, x0
478		bl	inv_dcache_range
479#endif
480#endif
481		adrp	x0, __BSS_START__
482		add	x0, x0, :lo12:__BSS_START__
483
484		adrp	x1, __BSS_END__
485		add	x1, x1, :lo12:__BSS_END__
486		sub	x1, x1, x0
487		bl	zeromem
488
489#if USE_COHERENT_MEM
490		adrp	x0, __COHERENT_RAM_START__
491		add	x0, x0, :lo12:__COHERENT_RAM_START__
492		adrp	x1, __COHERENT_RAM_END_UNALIGNED__
493		add	x1, x1, :lo12: __COHERENT_RAM_END_UNALIGNED__
494		sub	x1, x1, x0
495		bl	zeromem
496#endif
497
498#if defined(IMAGE_BL1) || (defined(IMAGE_BL2) && BL2_AT_EL3 && BL2_IN_XIP_MEM)
499		adrp	x0, __DATA_RAM_START__
500		add	x0, x0, :lo12:__DATA_RAM_START__
501		adrp	x1, __DATA_ROM_START__
502		add	x1, x1, :lo12:__DATA_ROM_START__
503		adrp	x2, __DATA_RAM_END__
504		add	x2, x2, :lo12:__DATA_RAM_END__
505		sub	x2, x2, x0
506		bl	memcpy16
507#endif
508	.endif /* _init_c_runtime */
509
510	/* ---------------------------------------------------------------------
511	 * Use SP_EL0 for the C runtime stack.
512	 * ---------------------------------------------------------------------
513	 */
514	msr	spsel, #0
515
516	/* ---------------------------------------------------------------------
517	 * Allocate a stack whose memory will be marked as Normal-IS-WBWA when
518	 * the MMU is enabled. There is no risk of reading stale stack memory
519	 * after enabling the MMU as only the primary CPU is running at the
520	 * moment.
521	 * ---------------------------------------------------------------------
522	 */
523	bl	plat_set_my_stack
524
525#if STACK_PROTECTOR_ENABLED
526	.if \_init_c_runtime
527	bl	update_stack_protector_canary
528	.endif /* _init_c_runtime */
529#endif
530	.endm
531
532	.macro	apply_at_speculative_wa
533#if ERRATA_SPECULATIVE_AT
534	/*
535	 * Explicitly save x30 so as to free up a register and to enable
536	 * branching and also, save x29 which will be used in the called
537	 * function
538	 */
539	stp	x29, x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X29]
540	bl	save_and_update_ptw_el1_sys_regs
541	ldp	x29, x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X29]
542#endif
543	.endm
544
545	.macro	restore_ptw_el1_sys_regs
546#if ERRATA_SPECULATIVE_AT
547	/* -----------------------------------------------------------
548	 * In case of ERRATA_SPECULATIVE_AT, must follow below order
549	 * to ensure that page table walk is not enabled until
550	 * restoration of all EL1 system registers. TCR_EL1 register
551	 * should be updated at the end which restores previous page
552	 * table walk setting of stage1 i.e.(TCR_EL1.EPDx) bits. ISB
553	 * ensures that CPU does below steps in order.
554	 *
555	 * 1. Ensure all other system registers are written before
556	 *    updating SCTLR_EL1 using ISB.
557	 * 2. Restore SCTLR_EL1 register.
558	 * 3. Ensure SCTLR_EL1 written successfully using ISB.
559	 * 4. Restore TCR_EL1 register.
560	 * -----------------------------------------------------------
561	 */
562	isb
563	ldp	x28, x29, [sp, #CTX_EL1_SYSREGS_OFFSET + CTX_SCTLR_EL1]
564	msr	sctlr_el1, x28
565	isb
566	msr	tcr_el1, x29
567#endif
568	.endm
569
570#endif /* EL3_COMMON_MACROS_S */
571