1/* 2 * Copyright (c) 2013-2024, Arm Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7#include <platform_def.h> 8 9#include <arch.h> 10#include <asm_macros.S> 11#include <bl31/ea_handle.h> 12#include <bl31/interrupt_mgmt.h> 13#include <bl31/sync_handle.h> 14#include <common/runtime_svc.h> 15#include <context.h> 16#include <cpu_macros.S> 17#include <el3_common_macros.S> 18#include <lib/el3_runtime/cpu_data.h> 19#include <lib/smccc.h> 20 21 .globl runtime_exceptions 22 23 .globl sync_exception_sp_el0 24 .globl irq_sp_el0 25 .globl fiq_sp_el0 26 .globl serror_sp_el0 27 28 .globl sync_exception_sp_elx 29 .globl irq_sp_elx 30 .globl fiq_sp_elx 31 .globl serror_sp_elx 32 33 .globl sync_exception_aarch64 34 .globl irq_aarch64 35 .globl fiq_aarch64 36 .globl serror_aarch64 37 38 .globl sync_exception_aarch32 39 .globl irq_aarch32 40 .globl fiq_aarch32 41 .globl serror_aarch32 42 43 /* 44 * Save LR and make x30 available as most of the routines in vector entry 45 * need a free register 46 */ 47 .macro save_x30 48 str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] 49 .endm 50 51 .macro restore_x30 52 ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] 53 .endm 54 55 /* 56 * Macro that synchronizes errors (EA) and checks for pending SError. 57 * On detecting a pending SError it either reflects it back to lower 58 * EL (KFH) or handles it in EL3 (FFH) based on EA routing model. 59 */ 60 .macro sync_and_handle_pending_serror 61 synchronize_errors 62 mrs x30, ISR_EL1 63 tbz x30, #ISR_A_SHIFT, 2f 64#if FFH_SUPPORT 65 mrs x30, scr_el3 66 tst x30, #SCR_EA_BIT 67 b.eq 1f 68 bl handle_pending_async_ea 69 b 2f 70#endif 711: 72 /* This function never returns, but need LR for decision making */ 73 bl reflect_pending_async_ea_to_lower_el 742: 75 .endm 76 77 /* --------------------------------------------------------------------- 78 * This macro handles Synchronous exceptions. 79 * Only SMC exceptions are supported. 80 * --------------------------------------------------------------------- 81 */ 82 .macro handle_sync_exception 83#if ENABLE_RUNTIME_INSTRUMENTATION 84 /* 85 * Read the timestamp value and store it in per-cpu data. The value 86 * will be extracted from per-cpu data by the C level SMC handler and 87 * saved to the PMF timestamp region. 88 */ 89 mrs x30, cntpct_el0 90 str x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X29] 91 mrs x29, tpidr_el3 92 str x30, [x29, #CPU_DATA_PMF_TS0_OFFSET] 93 ldr x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X29] 94#endif 95 96 mrs x30, esr_el3 97 ubfx x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH 98 99 /* Handle SMC exceptions separately from other synchronous exceptions */ 100 cmp x30, #EC_AARCH32_SMC 101 b.eq smc_handler32 102 103 cmp x30, #EC_AARCH64_SMC 104 b.eq sync_handler64 105 106 cmp x30, #EC_AARCH64_SYS 107 b.eq sync_handler64 108 109 cmp x30, #EC_IMP_DEF_EL3 110 b.eq imp_def_el3_handler 111 112 /* If FFH Support then try to handle lower EL EA exceptions. */ 113#if FFH_SUPPORT 114 mrs x30, scr_el3 115 tst x30, #SCR_EA_BIT 116 b.eq 1f 117 b handle_lower_el_sync_ea 118#endif 1191: 120 /* Synchronous exceptions other than the above are unhandled */ 121 b report_unhandled_exception 122 .endm 123 124vector_base runtime_exceptions 125 126 /* --------------------------------------------------------------------- 127 * Current EL with SP_EL0 : 0x0 - 0x200 128 * --------------------------------------------------------------------- 129 */ 130vector_entry sync_exception_sp_el0 131#ifdef MONITOR_TRAPS 132 stp x29, x30, [sp, #-16]! 133 134 mrs x30, esr_el3 135 ubfx x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH 136 137 /* Check for BRK */ 138 cmp x30, #EC_BRK 139 b.eq brk_handler 140 141 ldp x29, x30, [sp], #16 142#endif /* MONITOR_TRAPS */ 143 144 /* We don't expect any synchronous exceptions from EL3 */ 145 b report_unhandled_exception 146end_vector_entry sync_exception_sp_el0 147 148vector_entry irq_sp_el0 149 /* 150 * EL3 code is non-reentrant. Any asynchronous exception is a serious 151 * error. Loop infinitely. 152 */ 153 b report_unhandled_interrupt 154end_vector_entry irq_sp_el0 155 156 157vector_entry fiq_sp_el0 158 b report_unhandled_interrupt 159end_vector_entry fiq_sp_el0 160 161 162vector_entry serror_sp_el0 163 no_ret plat_handle_el3_ea 164end_vector_entry serror_sp_el0 165 166 /* --------------------------------------------------------------------- 167 * Current EL with SP_ELx: 0x200 - 0x400 168 * --------------------------------------------------------------------- 169 */ 170vector_entry sync_exception_sp_elx 171 /* 172 * This exception will trigger if anything went wrong during a previous 173 * exception entry or exit or while handling an earlier unexpected 174 * synchronous exception. There is a high probability that SP_EL3 is 175 * corrupted. 176 */ 177 b report_unhandled_exception 178end_vector_entry sync_exception_sp_elx 179 180vector_entry irq_sp_elx 181 b report_unhandled_interrupt 182end_vector_entry irq_sp_elx 183 184vector_entry fiq_sp_elx 185 b report_unhandled_interrupt 186end_vector_entry fiq_sp_elx 187 188vector_entry serror_sp_elx 189#if FFH_SUPPORT 190 /* 191 * This will trigger if the exception was taken due to SError in EL3 or 192 * because of pending asynchronous external aborts from lower EL that got 193 * triggered due to implicit/explicit synchronization in EL3 (SCR_EL3.EA=1) 194 * during EL3 entry. For the former case we continue with "plat_handle_el3_ea". 195 * The later case will occur when PSTATE.A bit is cleared in 196 * "handle_pending_async_ea". This means we are doing a nested 197 * exception in EL3. Call the handler for async EA which will eret back to 198 * original el3 handler if it is nested exception. Also, unmask EA so that we 199 * catch any further EA arise when handling this nested exception at EL3. 200 */ 201 save_x30 202 ldr x30, [sp, #CTX_EL3STATE_OFFSET + CTX_NESTED_EA_FLAG] 203 cbz x30, 1f 204 /* 205 * This is nested exception handling, clear the flag to avoid taking this 206 * path for further exceptions caused by EA handling 207 */ 208 str xzr, [sp, #CTX_EL3STATE_OFFSET + CTX_NESTED_EA_FLAG] 209 unmask_async_ea 210 b handle_lower_el_async_ea 2111: 212 restore_x30 213#endif 214 no_ret plat_handle_el3_ea 215 216end_vector_entry serror_sp_elx 217 218 /* --------------------------------------------------------------------- 219 * Lower EL using AArch64 : 0x400 - 0x600 220 * --------------------------------------------------------------------- 221 */ 222vector_entry sync_exception_aarch64 223 /* 224 * This exception vector will be the entry point for SMCs and traps 225 * that are unhandled at lower ELs most commonly. SP_EL3 should point 226 * to a valid cpu context where the general purpose and system register 227 * state can be saved. 228 */ 229 save_x30 230 apply_at_speculative_wa 231 sync_and_handle_pending_serror 232 handle_sync_exception 233end_vector_entry sync_exception_aarch64 234 235vector_entry irq_aarch64 236 save_x30 237 apply_at_speculative_wa 238 sync_and_handle_pending_serror 239 b handle_interrupt_exception 240end_vector_entry irq_aarch64 241 242vector_entry fiq_aarch64 243 save_x30 244 apply_at_speculative_wa 245 sync_and_handle_pending_serror 246 b handle_interrupt_exception 247end_vector_entry fiq_aarch64 248 249 /* 250 * Need to synchronize any outstanding SError since we can get a burst of errors. 251 * So reuse the sync mechanism to catch any further errors which are pending. 252 */ 253vector_entry serror_aarch64 254#if FFH_SUPPORT 255 save_x30 256 apply_at_speculative_wa 257 sync_and_handle_pending_serror 258 b handle_lower_el_async_ea 259#else 260 b report_unhandled_exception 261#endif 262end_vector_entry serror_aarch64 263 264 /* --------------------------------------------------------------------- 265 * Lower EL using AArch32 : 0x600 - 0x800 266 * --------------------------------------------------------------------- 267 */ 268vector_entry sync_exception_aarch32 269 /* 270 * This exception vector will be the entry point for SMCs and traps 271 * that are unhandled at lower ELs most commonly. SP_EL3 should point 272 * to a valid cpu context where the general purpose and system register 273 * state can be saved. 274 */ 275 save_x30 276 apply_at_speculative_wa 277 sync_and_handle_pending_serror 278 handle_sync_exception 279end_vector_entry sync_exception_aarch32 280 281vector_entry irq_aarch32 282 save_x30 283 apply_at_speculative_wa 284 sync_and_handle_pending_serror 285 b handle_interrupt_exception 286end_vector_entry irq_aarch32 287 288vector_entry fiq_aarch32 289 save_x30 290 apply_at_speculative_wa 291 sync_and_handle_pending_serror 292 b handle_interrupt_exception 293end_vector_entry fiq_aarch32 294 295 /* 296 * Need to synchronize any outstanding SError since we can get a burst of errors. 297 * So reuse the sync mechanism to catch any further errors which are pending. 298 */ 299vector_entry serror_aarch32 300#if FFH_SUPPORT 301 save_x30 302 apply_at_speculative_wa 303 sync_and_handle_pending_serror 304 b handle_lower_el_async_ea 305#else 306 b report_unhandled_exception 307#endif 308end_vector_entry serror_aarch32 309 310#ifdef MONITOR_TRAPS 311 .section .rodata.brk_string, "aS" 312brk_location: 313 .asciz "Error at instruction 0x" 314brk_message: 315 .asciz "Unexpected BRK instruction with value 0x" 316#endif /* MONITOR_TRAPS */ 317 318 /* --------------------------------------------------------------------- 319 * The following code handles secure monitor calls. 320 * Depending upon the execution state from where the SMC has been 321 * invoked, it frees some general purpose registers to perform the 322 * remaining tasks. They involve finding the runtime service handler 323 * that is the target of the SMC & switching to runtime stacks (SP_EL0) 324 * before calling the handler. 325 * 326 * Note that x30 has been explicitly saved and can be used here 327 * --------------------------------------------------------------------- 328 */ 329func sync_exception_handler 330smc_handler32: 331 /* Check whether aarch32 issued an SMC64 */ 332 tbnz x0, #FUNCID_CC_SHIFT, smc_prohibited 333 334sync_handler64: 335 /* NOTE: The code below must preserve x0-x4 */ 336 337 /* 338 * Save general purpose and ARMv8.3-PAuth registers (if enabled). 339 * Also save PMCR_EL0 and set the PSTATE to a known state. 340 */ 341 bl prepare_el3_entry 342 343#if ENABLE_PAUTH 344 /* Load and program APIAKey firmware key */ 345 bl pauth_load_bl31_apiakey 346#endif 347 348 /* 349 * Populate the parameters for the SMC handler. 350 * We already have x0-x4 in place. x5 will point to a cookie (not used 351 * now). x6 will point to the context structure (SP_EL3) and x7 will 352 * contain flags we need to pass to the handler. 353 */ 354 mov x5, xzr 355 mov x6, sp 356 357 /* 358 * Restore the saved C runtime stack value which will become the new 359 * SP_EL0 i.e. EL3 runtime stack. It was saved in the 'cpu_context' 360 * structure prior to the last ERET from EL3. 361 */ 362 ldr x12, [x6, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP] 363 364 /* Switch to SP_EL0 */ 365 msr spsel, #MODE_SP_EL0 366 367 /* 368 * Save the SPSR_EL3 and ELR_EL3 in case there is a world 369 * switch during SMC handling. 370 * TODO: Revisit if all system registers can be saved later. 371 */ 372 mrs x16, spsr_el3 373 mrs x17, elr_el3 374 stp x16, x17, [x6, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3] 375 376 /* Load SCR_EL3 */ 377 mrs x18, scr_el3 378 379 /* check for system register traps */ 380 mrs x16, esr_el3 381 ubfx x17, x16, #ESR_EC_SHIFT, #ESR_EC_LENGTH 382 cmp x17, #EC_AARCH64_SYS 383 b.eq sysreg_handler64 384 385 /* Clear flag register */ 386 mov x7, xzr 387 388#if ENABLE_RME 389 /* Copy SCR_EL3.NSE bit to the flag to indicate caller's security */ 390 ubfx x7, x18, #SCR_NSE_SHIFT, #1 391 392 /* 393 * Shift copied SCR_EL3.NSE bit by 5 to create space for 394 * SCR_EL3.NS bit. Bit 5 of the flag corresponds to 395 * the SCR_EL3.NSE bit. 396 */ 397 lsl x7, x7, #5 398#endif /* ENABLE_RME */ 399 400 /* Copy SCR_EL3.NS bit to the flag to indicate caller's security */ 401 bfi x7, x18, #0, #1 402 403 mov sp, x12 404 405 /* 406 * Per SMCCC documentation, bits [23:17] must be zero for Fast 407 * SMCs. Other values are reserved for future use. Ensure that 408 * these bits are zeroes, if not report as unknown SMC. 409 */ 410 tbz x0, #FUNCID_TYPE_SHIFT, 2f /* Skip check if its a Yield Call*/ 411 tst x0, #(FUNCID_FC_RESERVED_MASK << FUNCID_FC_RESERVED_SHIFT) 412 b.ne smc_unknown 413 414 /* 415 * Per SMCCCv1.3 a caller can set the SVE hint bit in the SMC FID 416 * passed through x0. Copy the SVE hint bit to flags and mask the 417 * bit in smc_fid passed to the standard service dispatcher. 418 * A service/dispatcher can retrieve the SVE hint bit state from 419 * flags using the appropriate helper. 420 */ 4212: 422 and x16, x0, #(FUNCID_SVE_HINT_MASK << FUNCID_SVE_HINT_SHIFT) 423 orr x7, x7, x16 424 bic x0, x0, #(FUNCID_SVE_HINT_MASK << FUNCID_SVE_HINT_SHIFT) 425 426 /* Get the unique owning entity number */ 427 ubfx x16, x0, #FUNCID_OEN_SHIFT, #FUNCID_OEN_WIDTH 428 ubfx x15, x0, #FUNCID_TYPE_SHIFT, #FUNCID_TYPE_WIDTH 429 orr x16, x16, x15, lsl #FUNCID_OEN_WIDTH 430 431 /* Load descriptor index from array of indices */ 432 adrp x14, rt_svc_descs_indices 433 add x14, x14, :lo12:rt_svc_descs_indices 434 ldrb w15, [x14, x16] 435 436 /* Any index greater than 127 is invalid. Check bit 7. */ 437 tbnz w15, 7, smc_unknown 438 439 /* 440 * Get the descriptor using the index 441 * x11 = (base + off), w15 = index 442 * 443 * handler = (base + off) + (index << log2(size)) 444 */ 445 adr_l x11, (__RT_SVC_DESCS_START__ + RT_SVC_DESC_HANDLE) 446 lsl w10, w15, #RT_SVC_SIZE_LOG2 447 ldr x15, [x11, w10, uxtw] 448 449 /* 450 * Call the Secure Monitor Call handler and then drop directly into 451 * el3_exit() which will program any remaining architectural state 452 * prior to issuing the ERET to the desired lower EL. 453 */ 454#if DEBUG 455 cbz x15, rt_svc_fw_critical_error 456#endif 457 blr x15 458 459 b el3_exit 460 461sysreg_handler64: 462 mov x0, x16 /* ESR_EL3, containing syndrome information */ 463 mov x1, x6 /* lower EL's context */ 464 mov x19, x6 /* save context pointer for after the call */ 465 mov sp, x12 /* EL3 runtime stack, as loaded above */ 466 467 /* int handle_sysreg_trap(uint64_t esr_el3, cpu_context_t *ctx); */ 468 bl handle_sysreg_trap 469 /* 470 * returns: 471 * -1: unhandled trap, UNDEF injection into lower EL 472 * 0: handled trap, return to the trapping instruction (repeating it) 473 * 1: handled trap, return to the next instruction 474 */ 475 476 tst w0, w0 477 b.mi 2f /* negative: undefined exception injection */ 478 479 b.eq 1f /* zero: do not change ELR_EL3 */ 480 /* positive: advance the PC to continue after the instruction */ 481 ldr x1, [x19, #CTX_EL3STATE_OFFSET + CTX_ELR_EL3] 482 add x1, x1, #4 483 str x1, [x19, #CTX_EL3STATE_OFFSET + CTX_ELR_EL3] 4841: 485 b el3_exit 4862: 487 /* 488 * UNDEF injection to lower EL, the support is only provided for lower 489 * EL in AArch64 mode, for AArch32 mode it will do elx_panic as before. 490 */ 491 mrs x0, spsr_el3 492 tst x0, #(SPSR_M_MASK << SPSR_M_SHIFT) 493 b.ne elx_panic 494 /* Pass context pointer as an argument to inject_undef64 */ 495 mov x0, x19 496 bl inject_undef64 497 b el3_exit 498 499smc_unknown: 500 /* 501 * Unknown SMC call. Populate return value with SMC_UNK and call 502 * el3_exit() which will restore the remaining architectural state 503 * i.e., SYS, GP and PAuth registers(if any) prior to issuing the ERET 504 * to the desired lower EL. 505 */ 506 mov x0, #SMC_UNK 507 str x0, [x6, #CTX_GPREGS_OFFSET + CTX_GPREG_X0] 508 b el3_exit 509 510smc_prohibited: 511 restore_ptw_el1_sys_regs 512 ldp x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28] 513 ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] 514 mov x0, #SMC_UNK 515 exception_return 516 517#if DEBUG 518rt_svc_fw_critical_error: 519 /* Switch to SP_ELx */ 520 msr spsel, #MODE_SP_ELX 521 no_ret report_unhandled_exception 522#endif 523endfunc sync_exception_handler 524 525 /* --------------------------------------------------------------------- 526 * This function handles FIQ or IRQ interrupts i.e. EL3, S-EL1 and NS 527 * interrupts. 528 * 529 * Note that x30 has been explicitly saved and can be used here 530 * --------------------------------------------------------------------- 531 */ 532func handle_interrupt_exception 533 /* 534 * Save general purpose and ARMv8.3-PAuth registers (if enabled). 535 * Also save PMCR_EL0 and set the PSTATE to a known state. 536 */ 537 bl prepare_el3_entry 538 539#if ENABLE_PAUTH 540 /* Load and program APIAKey firmware key */ 541 bl pauth_load_bl31_apiakey 542#endif 543 544 /* Save the EL3 system registers needed to return from this exception */ 545 mrs x0, spsr_el3 546 mrs x1, elr_el3 547 stp x0, x1, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3] 548 549 /* Switch to the runtime stack i.e. SP_EL0 */ 550 ldr x2, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP] 551 mov x20, sp 552 msr spsel, #MODE_SP_EL0 553 mov sp, x2 554 555 /* 556 * Find out whether this is a valid interrupt type. 557 * If the interrupt controller reports a spurious interrupt then return 558 * to where we came from. 559 */ 560 bl plat_ic_get_pending_interrupt_type 561 cmp x0, #INTR_TYPE_INVAL 562 b.eq interrupt_exit 563 564 /* 565 * Get the registered handler for this interrupt type. 566 * A NULL return value could be 'cause of the following conditions: 567 * 568 * a. An interrupt of a type was routed correctly but a handler for its 569 * type was not registered. 570 * 571 * b. An interrupt of a type was not routed correctly so a handler for 572 * its type was not registered. 573 * 574 * c. An interrupt of a type was routed correctly to EL3, but was 575 * deasserted before its pending state could be read. Another 576 * interrupt of a different type pended at the same time and its 577 * type was reported as pending instead. However, a handler for this 578 * type was not registered. 579 * 580 * a. and b. can only happen due to a programming error. The 581 * occurrence of c. could be beyond the control of Trusted Firmware. 582 * It makes sense to return from this exception instead of reporting an 583 * error. 584 */ 585 bl get_interrupt_type_handler 586 cbz x0, interrupt_exit 587 mov x21, x0 588 589 mov x0, #INTR_ID_UNAVAILABLE 590 591 /* Set the current security state in the 'flags' parameter */ 592 mrs x2, scr_el3 593 ubfx x1, x2, #0, #1 594 595 /* Restore the reference to the 'handle' i.e. SP_EL3 */ 596 mov x2, x20 597 598 /* x3 will point to a cookie (not used now) */ 599 mov x3, xzr 600 601 /* Call the interrupt type handler */ 602 blr x21 603 604interrupt_exit: 605 /* Return from exception, possibly in a different security state */ 606 b el3_exit 607endfunc handle_interrupt_exception 608 609func imp_def_el3_handler 610 /* Save GP registers */ 611 stp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0] 612 stp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2] 613 stp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4] 614 615 /* Get the cpu_ops pointer */ 616 bl get_cpu_ops_ptr 617 618 /* Get the cpu_ops exception handler */ 619 ldr x0, [x0, #CPU_E_HANDLER_FUNC] 620 621 /* 622 * If the reserved function pointer is NULL, this CPU does not have an 623 * implementation defined exception handler function 624 */ 625 cbz x0, el3_handler_exit 626 mrs x1, esr_el3 627 ubfx x1, x1, #ESR_EC_SHIFT, #ESR_EC_LENGTH 628 blr x0 629el3_handler_exit: 630 ldp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0] 631 ldp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2] 632 ldp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4] 633 restore_x30 634 no_ret report_unhandled_exception 635endfunc imp_def_el3_handler 636 637/* 638 * Handler for async EA from lower EL synchronized at EL3 entry in KFH mode. 639 * 640 * This scenario may arise when there is an error (EA) in the system which is not 641 * yet signaled to PE while executing in lower EL. During entry into EL3, the errors 642 * are synchronized either implicitly or explicitly causing async EA to pend at EL3. 643 * 644 * On detecting the pending EA (via ISR_EL1.A) and if the EA routing model is 645 * KFH (SCR_EL3.EA = 1) this handler reflects ther error back to lower EL. 646 * 647 * This function assumes x30 has been saved. 648 */ 649func reflect_pending_async_ea_to_lower_el 650 /* 651 * As the original exception was not handled we need to ensure that we return 652 * back to the instruction which caused the exception. To acheive that, eret 653 * to "elr-4" (Label "subtract_elr_el3") for SMC or simply eret otherwise 654 * (Label "skip_smc_check"). 655 * 656 * LIMITATION: It could be that async EA is masked at the target exception level 657 * or the priority of async EA wrt to the EL3/secure interrupt is lower, which 658 * causes back and forth between lower EL and EL3. In case of back and forth between 659 * lower EL and EL3, we can track the loop count in "CTX_NESTED_EA_FLAG" and leverage 660 * previous ELR in "CTX_SAVED_ELR_EL3" to detect this cycle and further panic 661 * to indicate a problem here (Label "check_loop_ctr"). If we are in this cycle, loop 662 * counter retains its value but if we do a normal el3_exit this flag gets cleared. 663 * However, setting SCR_EL3.IESB = 1, should give priority to SError handling 664 * as per AArch64.TakeException pseudo code in Arm ARM. 665 * 666 * TODO: In future if EL3 gets a capability to inject a virtual SError to lower 667 * ELs, we can remove the el3_panic and handle the original exception first and 668 * inject SError to lower EL before ereting back. 669 */ 670 stp x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28] 671 ldr x29, [sp, #CTX_EL3STATE_OFFSET + CTX_SAVED_ELR_EL3] 672 mrs x28, elr_el3 673 cmp x29, x28 674 b.eq check_loop_ctr 675 str x28, [sp, #CTX_EL3STATE_OFFSET + CTX_SAVED_ELR_EL3] 676 /* Zero the loop counter */ 677 str xzr, [sp, #CTX_EL3STATE_OFFSET + CTX_NESTED_EA_FLAG] 678 b skip_loop_ctr 679check_loop_ctr: 680 ldr x29, [sp, #CTX_EL3STATE_OFFSET + CTX_NESTED_EA_FLAG] 681 add x29, x29, #1 682 str x29, [sp, #CTX_EL3STATE_OFFSET + CTX_NESTED_EA_FLAG] 683 cmp x29, #ASYNC_EA_REPLAY_COUNTER 684 b.ge el3_panic 685skip_loop_ctr: 686 /* 687 * Logic to distinguish if we came from SMC or any other exception. 688 * Use offsets in vector entry to get which exception we are handling. 689 * In each vector entry of size 0x200, address "0x0-0x80" is for sync 690 * exception and "0x80-0x200" is for async exceptions. 691 * Use vector base address (vbar_el3) and exception offset (LR) to 692 * calculate whether the address we came from is any of the following 693 * "0x0-0x80", "0x200-0x280", "0x400-0x480" or "0x600-0x680" 694 */ 695 mrs x29, vbar_el3 696 sub x30, x30, x29 697 and x30, x30, #0x1ff 698 cmp x30, #0x80 699 b.ge skip_smc_check 700 /* Its a synchronous exception, Now check if it is SMC or not? */ 701 mrs x30, esr_el3 702 ubfx x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH 703 cmp x30, #EC_AARCH32_SMC 704 b.eq subtract_elr_el3 705 cmp x30, #EC_AARCH64_SMC 706 b.eq subtract_elr_el3 707 b skip_smc_check 708subtract_elr_el3: 709 sub x28, x28, #4 710skip_smc_check: 711 msr elr_el3, x28 712 ldp x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28] 713 ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] 714 exception_return 715endfunc reflect_pending_async_ea_to_lower_el 716 717 /* --------------------------------------------------------------------- 718 * The following code handles exceptions caused by BRK instructions. 719 * Following a BRK instruction, the only real valid cause of action is 720 * to print some information and panic, as the code that caused it is 721 * likely in an inconsistent internal state. 722 * 723 * This is initially intended to be used in conjunction with 724 * __builtin_trap. 725 * --------------------------------------------------------------------- 726 */ 727#ifdef MONITOR_TRAPS 728func brk_handler 729 /* Extract the ISS */ 730 mrs x10, esr_el3 731 ubfx x10, x10, #ESR_ISS_SHIFT, #ESR_ISS_LENGTH 732 733 /* Ensure the console is initialized */ 734 bl plat_crash_console_init 735 736 adr x4, brk_location 737 bl asm_print_str 738 mrs x4, elr_el3 739 bl asm_print_hex 740 bl asm_print_newline 741 742 adr x4, brk_message 743 bl asm_print_str 744 mov x4, x10 745 mov x5, #28 746 bl asm_print_hex_bits 747 bl asm_print_newline 748 749 no_ret plat_panic_handler 750endfunc brk_handler 751#endif /* MONITOR_TRAPS */ 752