1/* 2 * Copyright (c) 2013-2025, Arm Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7#include <arch.h> 8#include <asm_macros.S> 9#include <assert_macros.S> 10#include <context.h> 11#include <el3_common_macros.S> 12#include <platform_def.h> 13 14#if CTX_INCLUDE_FPREGS 15 .global fpregs_context_save 16 .global fpregs_context_restore 17#endif /* CTX_INCLUDE_FPREGS */ 18 19#if CTX_INCLUDE_SVE_REGS 20 .global sve_context_save 21 .global sve_context_restore 22#endif /* CTX_INCLUDE_SVE_REGS */ 23 24#if ERRATA_SPECULATIVE_AT 25 .global save_and_update_ptw_el1_sys_regs 26#endif /* ERRATA_SPECULATIVE_AT */ 27 28 .global prepare_el3_entry 29 .global restore_gp_pmcr_pauth_regs 30 .global el3_exit 31 32/* Following macros will be used if any of CTX_INCLUDE_FPREGS or CTX_INCLUDE_SVE_REGS is enabled */ 33#if CTX_INCLUDE_FPREGS || CTX_INCLUDE_SVE_REGS 34.macro fpregs_state_save base:req hold:req 35 mrs \hold, fpsr 36 str \hold, [\base, #CTX_SIMD_FPSR] 37 38 mrs \hold, fpcr 39 str \hold, [\base, #CTX_SIMD_FPCR] 40 41#if CTX_INCLUDE_AARCH32_REGS && CTX_INCLUDE_FPREGS 42 mrs \hold, fpexc32_el2 43 str \hold, [\base, #CTX_SIMD_FPEXC32] 44#endif 45.endm 46 47.macro fpregs_state_restore base:req hold:req 48 ldr \hold, [\base, #CTX_SIMD_FPSR] 49 msr fpsr, \hold 50 51 ldr \hold, [\base, #CTX_SIMD_FPCR] 52 msr fpcr, \hold 53 54#if CTX_INCLUDE_AARCH32_REGS && CTX_INCLUDE_FPREGS 55 ldr \hold, [\base, #CTX_SIMD_FPEXC32] 56 msr fpexc32_el2, \hold 57#endif 58.endm 59 60#endif /* CTX_INCLUDE_FPREGS || CTX_INCLUDE_SVE_REGS */ 61 62/* ------------------------------------------------------------------ 63 * The following function follows the aapcs_64 strictly to use 64 * x9-x17 (temporary caller-saved registers according to AArch64 PCS) 65 * to save floating point register context. It assumes that 'x0' is 66 * pointing to a 'fp_regs' structure where the register context will 67 * be saved. 68 * 69 * Access to VFP registers will trap if CPTR_EL3.TFP is set. 70 * However currently we don't use VFP registers nor set traps in 71 * Trusted Firmware, and assume it's cleared. 72 * 73 * TODO: Revisit when VFP is used in secure world 74 * ------------------------------------------------------------------ 75 */ 76#if CTX_INCLUDE_FPREGS 77func fpregs_context_save 78.arch_extension fp 79 /* Temporarily enable floating point */ 80 81 /* Save x0 and pass its original value to fpregs_state_save */ 82 mov x1, x0 83 84 stp q0, q1, [x0], #32 85 stp q2, q3, [x0], #32 86 stp q4, q5, [x0], #32 87 stp q6, q7, [x0], #32 88 stp q8, q9, [x0], #32 89 stp q10, q11, [x0], #32 90 stp q12, q13, [x0], #32 91 stp q14, q15, [x0], #32 92 stp q16, q17, [x0], #32 93 stp q18, q19, [x0], #32 94 stp q20, q21, [x0], #32 95 stp q22, q23, [x0], #32 96 stp q24, q25, [x0], #32 97 stp q26, q27, [x0], #32 98 stp q28, q29, [x0], #32 99 stp q30, q31, [x0], #32 100 101 fpregs_state_save x1, x9 102 103.arch_extension nofp 104 ret 105endfunc fpregs_context_save 106 107/* ------------------------------------------------------------------ 108 * The following function follows the aapcs_64 strictly to use x9-x17 109 * (temporary caller-saved registers according to AArch64 PCS) to 110 * restore floating point register context. It assumes that 'x0' is 111 * pointing to a 'fp_regs' structure from where the register context 112 * will be restored. 113 * 114 * Access to VFP registers will trap if CPTR_EL3.TFP is set. 115 * However currently we don't use VFP registers nor set traps in 116 * Trusted Firmware, and assume it's cleared. 117 * 118 * TODO: Revisit when VFP is used in secure world 119 * ------------------------------------------------------------------ 120 */ 121func fpregs_context_restore 122.arch_extension fp 123 /* Temporarily enable floating point */ 124 125 /* Save x0 and pass its original value to fpregs_state_restore */ 126 mov x1, x0 127 128 ldp q0, q1, [x0], #32 129 ldp q2, q3, [x0], #32 130 ldp q4, q5, [x0], #32 131 ldp q6, q7, [x0], #32 132 ldp q8, q9, [x0], #32 133 ldp q10, q11, [x0], #32 134 ldp q12, q13, [x0], #32 135 ldp q14, q15, [x0], #32 136 ldp q16, q17, [x0], #32 137 ldp q18, q19, [x0], #32 138 ldp q20, q21, [x0], #32 139 ldp q22, q23, [x0], #32 140 ldp q24, q25, [x0], #32 141 ldp q26, q27, [x0], #32 142 ldp q28, q29, [x0], #32 143 ldp q30, q31, [x0], #32 144 145 fpregs_state_restore x1, x9 146 147.arch_extension nofp 148 ret 149endfunc fpregs_context_restore 150#endif /* CTX_INCLUDE_FPREGS */ 151 152#if CTX_INCLUDE_SVE_REGS 153/* 154 * Helper macros for SVE predicates save/restore operations. 155 */ 156.macro sve_predicate_op op:req reg:req 157 \op p0, [\reg, #0, MUL VL] 158 \op p1, [\reg, #1, MUL VL] 159 \op p2, [\reg, #2, MUL VL] 160 \op p3, [\reg, #3, MUL VL] 161 \op p4, [\reg, #4, MUL VL] 162 \op p5, [\reg, #5, MUL VL] 163 \op p6, [\reg, #6, MUL VL] 164 \op p7, [\reg, #7, MUL VL] 165 \op p8, [\reg, #8, MUL VL] 166 \op p9, [\reg, #9, MUL VL] 167 \op p10, [\reg, #10, MUL VL] 168 \op p11, [\reg, #11, MUL VL] 169 \op p12, [\reg, #12, MUL VL] 170 \op p13, [\reg, #13, MUL VL] 171 \op p14, [\reg, #14, MUL VL] 172 \op p15, [\reg, #15, MUL VL] 173.endm 174 175.macro sve_vectors_op op:req reg:req 176 \op z0, [\reg, #0, MUL VL] 177 \op z1, [\reg, #1, MUL VL] 178 \op z2, [\reg, #2, MUL VL] 179 \op z3, [\reg, #3, MUL VL] 180 \op z4, [\reg, #4, MUL VL] 181 \op z5, [\reg, #5, MUL VL] 182 \op z6, [\reg, #6, MUL VL] 183 \op z7, [\reg, #7, MUL VL] 184 \op z8, [\reg, #8, MUL VL] 185 \op z9, [\reg, #9, MUL VL] 186 \op z10, [\reg, #10, MUL VL] 187 \op z11, [\reg, #11, MUL VL] 188 \op z12, [\reg, #12, MUL VL] 189 \op z13, [\reg, #13, MUL VL] 190 \op z14, [\reg, #14, MUL VL] 191 \op z15, [\reg, #15, MUL VL] 192 \op z16, [\reg, #16, MUL VL] 193 \op z17, [\reg, #17, MUL VL] 194 \op z18, [\reg, #18, MUL VL] 195 \op z19, [\reg, #19, MUL VL] 196 \op z20, [\reg, #20, MUL VL] 197 \op z21, [\reg, #21, MUL VL] 198 \op z22, [\reg, #22, MUL VL] 199 \op z23, [\reg, #23, MUL VL] 200 \op z24, [\reg, #24, MUL VL] 201 \op z25, [\reg, #25, MUL VL] 202 \op z26, [\reg, #26, MUL VL] 203 \op z27, [\reg, #27, MUL VL] 204 \op z28, [\reg, #28, MUL VL] 205 \op z29, [\reg, #29, MUL VL] 206 \op z30, [\reg, #30, MUL VL] 207 \op z31, [\reg, #31, MUL VL] 208.endm 209 210/* ------------------------------------------------------------------ 211 * The following function follows the aapcs_64 strictly to use x9-x17 212 * (temporary caller-saved registers according to AArch64 PCS) to 213 * restore SVE register context. It assumes that 'x0' is 214 * pointing to a 'sve_regs_t' structure to which the register context 215 * will be saved. 216 * ------------------------------------------------------------------ 217 */ 218func sve_context_save 219.arch_extension sve 220 /* Predicate registers */ 221 mov x13, #CTX_SIMD_PREDICATES 222 add x9, x0, x13 223 sve_predicate_op str, x9 224 225 /* Save FFR after predicates */ 226 mov x13, #CTX_SIMD_FFR 227 add x9, x0, x13 228 rdffr p0.b 229 str p0, [x9] 230 231 /* Save vector registers */ 232 mov x13, #CTX_SIMD_VECTORS 233 add x9, x0, x13 234 sve_vectors_op str, x9 235.arch_extension nosve 236 237 /* Save FPSR, FPCR and FPEXC32 */ 238 fpregs_state_save x0, x9 239 240 ret 241endfunc sve_context_save 242 243/* ------------------------------------------------------------------ 244 * The following function follows the aapcs_64 strictly to use x9-x17 245 * (temporary caller-saved registers according to AArch64 PCS) to 246 * restore SVE register context. It assumes that 'x0' is pointing to 247 * a 'sve_regs_t' structure from where the register context will be 248 * restored. 249 * ------------------------------------------------------------------ 250 */ 251func sve_context_restore 252.arch_extension sve 253 /* Restore FFR register before predicates */ 254 mov x13, #CTX_SIMD_FFR 255 add x9, x0, x13 256 ldr p0, [x9] 257 wrffr p0.b 258 259 /* Restore predicate registers */ 260 mov x13, #CTX_SIMD_PREDICATES 261 add x9, x0, x13 262 sve_predicate_op ldr, x9 263 264 /* Restore vector registers */ 265 mov x13, #CTX_SIMD_VECTORS 266 add x9, x0, x13 267 sve_vectors_op ldr, x9 268.arch_extension nosve 269 270 /* Restore FPSR, FPCR and FPEXC32 */ 271 fpregs_state_restore x0, x9 272 ret 273endfunc sve_context_restore 274#endif /* CTX_INCLUDE_SVE_REGS */ 275 276 /* 277 * Set SCR_EL3.EA bit to enable SErrors at EL3 278 */ 279 .macro enable_serror_at_el3 280 mrs x8, scr_el3 281 orr x8, x8, #SCR_EA_BIT 282 msr scr_el3, x8 283 .endm 284 285 /* 286 * Set the PSTATE bits not set when the exception was taken as 287 * described in the AArch64.TakeException() pseudocode function 288 * in ARM DDI 0487F.c page J1-7635 to a default value. 289 */ 290 .macro set_unset_pstate_bits 291 /* 292 * If Data Independent Timing (DIT) functionality is implemented, 293 * always enable DIT in EL3 294 */ 295#if ENABLE_FEAT_DIT 296#if ENABLE_FEAT_DIT >= 2 297 mrs x8, id_aa64pfr0_el1 298 and x8, x8, #(ID_AA64PFR0_DIT_MASK << ID_AA64PFR0_DIT_SHIFT) 299 cbz x8, 1f 300#endif 301 mov x8, #DIT_BIT 302 msr DIT, x8 3031: 304#endif /* ENABLE_FEAT_DIT */ 305 .endm /* set_unset_pstate_bits */ 306 307/*------------------------------------------------------------------------- 308 * This macro checks the ENABLE_FEAT_MPAM state, performs ID register 309 * check to see if the platform supports MPAM extension and restores MPAM3 310 * register value if it is FEAT_STATE_ENABLED/FEAT_STATE_CHECKED. 311 * 312 * This is particularly more complicated because we can't check 313 * if the platform supports MPAM by looking for status of a particular bit 314 * in the MDCR_EL3 or CPTR_EL3 register like other extensions. 315 * ------------------------------------------------------------------------ 316 */ 317 318 .macro restore_mpam3_el3 319#if ENABLE_FEAT_MPAM 320#if ENABLE_FEAT_MPAM >= 2 321 mrs x8, id_aa64pfr0_el1 322 lsr x8, x8, #(ID_AA64PFR0_MPAM_SHIFT) 323 and x8, x8, #(ID_AA64PFR0_MPAM_MASK) 324 mrs x7, id_aa64pfr1_el1 325 lsr x7, x7, #(ID_AA64PFR1_MPAM_FRAC_SHIFT) 326 and x7, x7, #(ID_AA64PFR1_MPAM_FRAC_MASK) 327 orr x7, x7, x8 328 cbz x7, no_mpam 329#endif 330 /* ----------------------------------------------------------- 331 * Restore MPAM3_EL3 register as per context state 332 * Currently we only enable MPAM for NS world and trap to EL3 333 * for MPAM access in lower ELs of Secure and Realm world 334 * x9 holds address of the per_world context 335 * ----------------------------------------------------------- 336 */ 337 338 ldr x17, [x9, #CTX_MPAM3_EL3] 339 msr S3_6_C10_C5_0, x17 /* mpam3_el3 */ 340 341no_mpam: 342#endif 343 .endm /* restore_mpam3_el3 */ 344 345/* ------------------------------------------------------------------ 346 * The following macro is used to save all the general purpose 347 * registers and swap the FEAT_PAUTH keys with BL31's keys in 348 * cpu_data. It also checks if the Secure Cycle Counter (PMCCNTR_EL0) 349 * is disabled in EL3/Secure (ARMv8.5-PMU), wherein PMCCNTR_EL0 needs 350 * not to be saved/restored during world switch. 351 * 352 * Ideally we would only save and restore the callee saved registers 353 * when a world switch occurs but that type of implementation is more 354 * complex. So currently we will always save and restore these 355 * registers on entry and exit of EL3. 356 * clobbers: x18 357 * ------------------------------------------------------------------ 358 */ 359 .macro save_gp_pmcr_pauth_regs 360 stp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0] 361 stp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2] 362 stp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4] 363 stp x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6] 364 stp x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8] 365 stp x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10] 366 stp x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12] 367 stp x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14] 368 stp x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16] 369 stp x18, x19, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18] 370 stp x20, x21, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X20] 371 stp x22, x23, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X22] 372 stp x24, x25, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X24] 373 stp x26, x27, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X26] 374 stp x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28] 375 mrs x18, sp_el0 376 str x18, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_SP_EL0] 377 378 /* PMUv3 is presumed to be always present */ 379 mrs x9, pmcr_el0 380 str x9, [sp, #CTX_EL3STATE_OFFSET + CTX_PMCR_EL0] 381#if CTX_INCLUDE_PAUTH_REGS 382#if CTX_INCLUDE_PAUTH_REGS == 2 383 /* Skip if not present in hardware */ 384 is_feat_pauth_present_asm x9, x10 385 beq no_pauth_\@ 386#endif 387 /* ---------------------------------------------------------- 388 * Save the ARMv8.3-PAuth keys as they are not banked 389 * by exception level 390 * ---------------------------------------------------------- 391 */ 392 add x19, sp, #CTX_PAUTH_REGS_OFFSET 393 394 mrs x20, APIAKeyLo_EL1 /* x21:x20 = APIAKey */ 395 mrs x21, APIAKeyHi_EL1 396 mrs x22, APIBKeyLo_EL1 /* x23:x22 = APIBKey */ 397 mrs x23, APIBKeyHi_EL1 398 mrs x24, APDAKeyLo_EL1 /* x25:x24 = APDAKey */ 399 mrs x25, APDAKeyHi_EL1 400 mrs x26, APDBKeyLo_EL1 /* x27:x26 = APDBKey */ 401 mrs x27, APDBKeyHi_EL1 402 mrs x28, APGAKeyLo_EL1 /* x29:x28 = APGAKey */ 403 mrs x29, APGAKeyHi_EL1 404 405 stp x20, x21, [x19, #CTX_PACIAKEY_LO] 406 stp x22, x23, [x19, #CTX_PACIBKEY_LO] 407 stp x24, x25, [x19, #CTX_PACDAKEY_LO] 408 stp x26, x27, [x19, #CTX_PACDBKEY_LO] 409 stp x28, x29, [x19, #CTX_PACGAKEY_LO] 410#if ENABLE_PAUTH 411#if IMAGE_BL31 412 /* tpidr_el3 contains the address of the cpu_data structure */ 413 mrs x9, tpidr_el3 414 /* Load APIAKey from cpu_data */ 415 ldp x10, x11, [x9, #CPU_DATA_APIAKEY_OFFSET] 416#endif /* IMAGE_BL31 */ 417 418#if IMAGE_BL1 419 /* BL1 does not use cpu_data and has dedicated storage */ 420 adr_l x9, bl1_apiakey 421 ldp x10, x11, [x9] 422#endif /* IMAGE_BL1 */ 423 424 /* Program instruction key A */ 425 msr APIAKeyLo_EL1, x10 426 msr APIAKeyHi_EL1, x11 427no_pauth_\@: 428#endif /* ENABLE_PAUTH */ 429#endif /* CTX_INCLUDE_PAUTH_REGS */ 430 .endm /* save_gp_pmcr_pauth_regs */ 431 432/* ----------------------------------------------------------------- 433 * This function saves the context and sets the PSTATE to a known 434 * state, preparing entry to el3. 435 * Save all the general purpose and ARMv8.3-PAuth (if enabled) 436 * registers. 437 * Then set any of the PSTATE bits that are not set by hardware 438 * according to the Aarch64.TakeException pseudocode in the Arm 439 * Architecture Reference Manual to a default value for EL3. 440 * clobbers: x17 441 * ----------------------------------------------------------------- 442 */ 443func prepare_el3_entry 444 /* 445 * context is about to mutate, so make sure we don't affect any still 446 * in-flight profiling operations. We don't care that they actually 447 * finish, that can still be later. NOP if not present 448 */ 449#if ENABLE_SPE_FOR_NS 450 psb_csync 451#endif 452#if ENABLE_TRBE_FOR_NS 453 tsb_csync 454#endif 455 isb 456 save_gp_pmcr_pauth_regs 457 setup_el3_execution_context 458 ret 459endfunc prepare_el3_entry 460 461/* ------------------------------------------------------------------ 462 * This function restores ARMv8.3-PAuth (if enabled) and all general 463 * purpose registers except x30 from the CPU context. 464 * x30 register must be explicitly restored by the caller. 465 * ------------------------------------------------------------------ 466 */ 467func restore_gp_pmcr_pauth_regs 468#if CTX_INCLUDE_PAUTH_REGS 469#if CTX_INCLUDE_PAUTH_REGS == 2 470 /* Skip if not present in hardware */ 471 is_feat_pauth_present_asm x0, x1 472 beq no_pauth 473#endif 474 /* Restore the ARMv8.3 PAuth keys */ 475 add x10, sp, #CTX_PAUTH_REGS_OFFSET 476 477 ldp x0, x1, [x10, #CTX_PACIAKEY_LO] /* x1:x0 = APIAKey */ 478 ldp x2, x3, [x10, #CTX_PACIBKEY_LO] /* x3:x2 = APIBKey */ 479 ldp x4, x5, [x10, #CTX_PACDAKEY_LO] /* x5:x4 = APDAKey */ 480 ldp x6, x7, [x10, #CTX_PACDBKEY_LO] /* x7:x6 = APDBKey */ 481 ldp x8, x9, [x10, #CTX_PACGAKEY_LO] /* x9:x8 = APGAKey */ 482 483 msr APIAKeyLo_EL1, x0 484 msr APIAKeyHi_EL1, x1 485 msr APIBKeyLo_EL1, x2 486 msr APIBKeyHi_EL1, x3 487 msr APDAKeyLo_EL1, x4 488 msr APDAKeyHi_EL1, x5 489 msr APDBKeyLo_EL1, x6 490 msr APDBKeyHi_EL1, x7 491 msr APGAKeyLo_EL1, x8 492 msr APGAKeyHi_EL1, x9 493no_pauth: 494#endif /* CTX_INCLUDE_PAUTH_REGS */ 495 496 /* PMUv3 is presumed to be always present */ 497 ldr x0, [sp, #CTX_EL3STATE_OFFSET + CTX_PMCR_EL0] 498 msr pmcr_el0, x0 499 ldp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0] 500 ldp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2] 501 ldp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4] 502 ldp x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6] 503 ldp x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8] 504 ldp x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10] 505 ldp x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12] 506 ldp x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14] 507 ldp x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16] 508 ldp x18, x19, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18] 509 ldp x20, x21, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X20] 510 ldp x22, x23, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X22] 511 ldp x24, x25, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X24] 512 ldp x26, x27, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X26] 513 ldr x28, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_SP_EL0] 514 msr sp_el0, x28 515 ldp x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28] 516 ret 517endfunc restore_gp_pmcr_pauth_regs 518 519#if ERRATA_SPECULATIVE_AT 520/* -------------------------------------------------------------------- 521 * In case of ERRATA_SPECULATIVE_AT, save SCTLR_EL1 and TCR_EL1 522 * registers and update EL1 registers to disable stage1 and stage2 523 * page table walk. 524 * -------------------------------------------------------------------- 525 */ 526func save_and_update_ptw_el1_sys_regs 527 /* ---------------------------------------------------------- 528 * Save only sctlr_el1 and tcr_el1 registers 529 * ---------------------------------------------------------- 530 */ 531 mrs x29, sctlr_el1 532 str x29, [sp, #(CTX_ERRATA_SPEC_AT_OFFSET + CTX_ERRATA_SPEC_AT_SCTLR_EL1)] 533 mrs x29, tcr_el1 534 str x29, [sp, #(CTX_ERRATA_SPEC_AT_OFFSET + CTX_ERRATA_SPEC_AT_TCR_EL1)] 535 536 /* ------------------------------------------------------------ 537 * Must follow below order in order to disable page table 538 * walk for lower ELs (EL1 and EL0). First step ensures that 539 * page table walk is disabled for stage1 and second step 540 * ensures that page table walker should use TCR_EL1.EPDx 541 * bits to perform address translation. ISB ensures that CPU 542 * does these 2 steps in order. 543 * 544 * 1. Update TCR_EL1.EPDx bits to disable page table walk by 545 * stage1. 546 * 2. Enable MMU bit to avoid identity mapping via stage2 547 * and force TCR_EL1.EPDx to be used by the page table 548 * walker. 549 * ------------------------------------------------------------ 550 */ 551 orr x29, x29, #(TCR_EPD0_BIT) 552 orr x29, x29, #(TCR_EPD1_BIT) 553 msr tcr_el1, x29 554 isb 555 mrs x29, sctlr_el1 556 orr x29, x29, #SCTLR_M_BIT 557 msr sctlr_el1, x29 558 isb 559 ret 560endfunc save_and_update_ptw_el1_sys_regs 561 562#endif /* ERRATA_SPECULATIVE_AT */ 563 564/* ----------------------------------------------------------------- 565* The below macro returns the address of the per_world context for 566* the security state, retrieved through "get_security_state" macro. 567* The per_world context address is returned in the register argument. 568* Clobbers: x9, x10 569* ------------------------------------------------------------------ 570*/ 571 572.macro get_per_world_context _reg:req 573 ldr x10, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3] 574 get_security_state x9, x10 575 mov_imm x10, (CTX_PERWORLD_EL3STATE_END - CTX_CPTR_EL3) 576 mul x9, x9, x10 577 adrp x10, per_world_context 578 add x10, x10, :lo12:per_world_context 579 add x9, x9, x10 580 mov \_reg, x9 581.endm 582 583/* ------------------------------------------------------------------ 584 * This routine assumes that the SP_EL3 is pointing to a valid 585 * context structure from where the gp regs and other special 586 * registers can be retrieved. 587 * ------------------------------------------------------------------ 588 */ 589func el3_exit 590#if ENABLE_ASSERTIONS 591 /* el3_exit assumes SP_EL0 on entry */ 592 mrs x17, spsel 593 cmp x17, #MODE_SP_EL0 594 ASM_ASSERT(eq) 595#endif /* ENABLE_ASSERTIONS */ 596 597 /* ---------------------------------------------------------- 598 * Save the current SP_EL0 i.e. the EL3 runtime stack which 599 * will be used for handling the next SMC. 600 * Then switch to SP_EL3. 601 * ---------------------------------------------------------- 602 */ 603 mov x17, sp 604 msr spsel, #MODE_SP_ELX 605 str x17, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP] 606 607 /* ---------------------------------------------------------- 608 * Restore CPTR_EL3. 609 * ---------------------------------------------------------- */ 610 611 /* The address of the per_world context is stored in x9 */ 612 get_per_world_context x9 613 614 ldp x19, x20, [x9, #CTX_CPTR_EL3] 615 msr cptr_el3, x19 616 617#if IMAGE_BL31 618 restore_mpam3_el3 619 620#endif /* IMAGE_BL31 */ 621 622#if IMAGE_BL31 && DYNAMIC_WORKAROUND_CVE_2018_3639 623 /* ---------------------------------------------------------- 624 * Restore mitigation state as it was on entry to EL3 625 * ---------------------------------------------------------- 626 */ 627 ldr x17, [sp, #CTX_CVE_2018_3639_OFFSET + CTX_CVE_2018_3639_DISABLE] 628 cbz x17, 1f 629 blr x17 6301: 631#endif /* IMAGE_BL31 && DYNAMIC_WORKAROUND_CVE_2018_3639 */ 632 633#if IMAGE_BL31 634 synchronize_errors 635#endif /* IMAGE_BL31 */ 636 637 /* -------------------------------------------------------------- 638 * Restore MDCR_EL3, SPSR_EL3, ELR_EL3 and SCR_EL3 prior to ERET 639 * -------------------------------------------------------------- 640 */ 641 ldp x16, x17, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3] 642 ldr x18, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3] 643 ldr x19, [sp, #CTX_EL3STATE_OFFSET + CTX_MDCR_EL3] 644 msr spsr_el3, x16 645 msr elr_el3, x17 646 msr scr_el3, x18 647 msr mdcr_el3, x19 648 649 restore_ptw_el1_sys_regs 650 651 /* ---------------------------------------------------------- 652 * Restore general purpose (including x30), PMCR_EL0 and 653 * ARMv8.3-PAuth registers. 654 * Exit EL3 via ERET to a lower exception level. 655 * ---------------------------------------------------------- 656 */ 657 bl restore_gp_pmcr_pauth_regs 658 ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] 659 660#ifdef IMAGE_BL31 661 /* Clear the EL3 flag as we are exiting el3 */ 662 str xzr, [sp, #CTX_EL3STATE_OFFSET + CTX_NESTED_EA_FLAG] 663#endif /* IMAGE_BL31 */ 664 665 exception_return 666 667endfunc el3_exit 668