/* * Copyright (c) 2013-2021, ARM Limited and Contributors. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ #include #include #include #include #include #include #include #include #include #include .globl runtime_exceptions .globl sync_exception_sp_el0 .globl irq_sp_el0 .globl fiq_sp_el0 .globl serror_sp_el0 .globl sync_exception_sp_elx .globl irq_sp_elx .globl fiq_sp_elx .globl serror_sp_elx .globl sync_exception_aarch64 .globl irq_aarch64 .globl fiq_aarch64 .globl serror_aarch64 .globl sync_exception_aarch32 .globl irq_aarch32 .globl fiq_aarch32 .globl serror_aarch32 /* * Macro that prepares entry to EL3 upon taking an exception. * * With RAS_EXTENSION, this macro synchronizes pending errors with an ESB * instruction. When an error is thus synchronized, the handling is * delegated to platform EA handler. * * Without RAS_EXTENSION, this macro synchronizes pending errors using * a DSB, unmasks Asynchronous External Aborts and saves X30 before * setting the flag CTX_IS_IN_EL3. */ .macro check_and_unmask_ea #if RAS_EXTENSION /* Synchronize pending External Aborts */ esb /* Unmask the SError interrupt */ msr daifclr, #DAIF_ABT_BIT /* * Explicitly save x30 so as to free up a register and to enable * branching */ str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] /* Check for SErrors synchronized by the ESB instruction */ mrs x30, DISR_EL1 tbz x30, #DISR_A_BIT, 1f /* * Save general purpose and ARMv8.3-PAuth registers (if enabled). * If Secure Cycle Counter is not disabled in MDCR_EL3 when * ARMv8.5-PMU is implemented, save PMCR_EL0 and disable Cycle Counter. */ bl save_gp_pmcr_pauth_regs bl handle_lower_el_ea_esb /* Restore general purpose, PMCR_EL0 and ARMv8.3-PAuth registers */ bl restore_gp_pmcr_pauth_regs 1: #else /* * For SoCs which do not implement RAS, use DSB as a barrier to * synchronize pending external aborts. */ dsb sy /* Unmask the SError interrupt */ msr daifclr, #DAIF_ABT_BIT /* Use ISB for the above unmask operation to take effect immediately */ isb /* * Refer Note 1. No need to restore X30 as both handle_sync_exception * and handle_interrupt_exception macro which follow this macro modify * X30 anyway. */ str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] mov x30, #1 str x30, [sp, #CTX_EL3STATE_OFFSET + CTX_IS_IN_EL3] dmb sy #endif .endm #if !RAS_EXTENSION /* * Note 1: The explicit DSB at the entry of various exception vectors * for handling exceptions from lower ELs can inadvertently trigger an * SError exception in EL3 due to pending asynchronous aborts in lower * ELs. This will end up being handled by serror_sp_elx which will * ultimately panic and die. * The way to workaround is to update a flag to indicate if the exception * truly came from EL3. This flag is allocated in the cpu_context * structure and located at offset "CTX_EL3STATE_OFFSET + CTX_IS_IN_EL3" * This is not a bullet proof solution to the problem at hand because * we assume the instructions following "isb" that help to update the * flag execute without causing further exceptions. */ /* --------------------------------------------------------------------- * This macro handles Asynchronous External Aborts. * --------------------------------------------------------------------- */ .macro handle_async_ea /* * Use a barrier to synchronize pending external aborts. */ dsb sy /* Unmask the SError interrupt */ msr daifclr, #DAIF_ABT_BIT /* Use ISB for the above unmask operation to take effect immediately */ isb /* Refer Note 1 */ str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] mov x30, #1 str x30, [sp, #CTX_EL3STATE_OFFSET + CTX_IS_IN_EL3] dmb sy b handle_lower_el_async_ea .endm /* * This macro checks if the exception was taken due to SError in EL3 or * because of pending asynchronous external aborts from lower EL that got * triggered due to explicit synchronization in EL3. Refer Note 1. */ .macro check_if_serror_from_EL3 /* Assumes SP_EL3 on entry */ str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] ldr x30, [sp, #CTX_EL3STATE_OFFSET + CTX_IS_IN_EL3] cbnz x30, exp_from_EL3 /* Handle asynchronous external abort from lower EL */ b handle_lower_el_async_ea exp_from_EL3: /* Jump to plat_handle_el3_ea which does not return */ .endm #endif /* --------------------------------------------------------------------- * This macro handles Synchronous exceptions. * Only SMC exceptions are supported. * --------------------------------------------------------------------- */ .macro handle_sync_exception #if ENABLE_RUNTIME_INSTRUMENTATION /* * Read the timestamp value and store it in per-cpu data. The value * will be extracted from per-cpu data by the C level SMC handler and * saved to the PMF timestamp region. */ mrs x30, cntpct_el0 str x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X29] mrs x29, tpidr_el3 str x30, [x29, #CPU_DATA_PMF_TS0_OFFSET] ldr x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X29] #endif mrs x30, esr_el3 ubfx x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH /* Handle SMC exceptions separately from other synchronous exceptions */ cmp x30, #EC_AARCH32_SMC b.eq smc_handler32 cmp x30, #EC_AARCH64_SMC b.eq smc_handler64 /* Synchronous exceptions other than the above are assumed to be EA */ ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] b enter_lower_el_sync_ea .endm /* --------------------------------------------------------------------- * This macro handles FIQ or IRQ interrupts i.e. EL3, S-EL1 and NS * interrupts. * --------------------------------------------------------------------- */ .macro handle_interrupt_exception label /* * Save general purpose and ARMv8.3-PAuth registers (if enabled). * If Secure Cycle Counter is not disabled in MDCR_EL3 when * ARMv8.5-PMU is implemented, save PMCR_EL0 and disable Cycle Counter. */ bl save_gp_pmcr_pauth_regs #if ENABLE_PAUTH /* Load and program APIAKey firmware key */ bl pauth_load_bl31_apiakey #endif /* Save the EL3 system registers needed to return from this exception */ mrs x0, spsr_el3 mrs x1, elr_el3 stp x0, x1, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3] /* Switch to the runtime stack i.e. SP_EL0 */ ldr x2, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP] mov x20, sp msr spsel, #MODE_SP_EL0 mov sp, x2 /* * Find out whether this is a valid interrupt type. * If the interrupt controller reports a spurious interrupt then return * to where we came from. */ bl plat_ic_get_pending_interrupt_type cmp x0, #INTR_TYPE_INVAL b.eq interrupt_exit_\label /* * Get the registered handler for this interrupt type. * A NULL return value could be 'cause of the following conditions: * * a. An interrupt of a type was routed correctly but a handler for its * type was not registered. * * b. An interrupt of a type was not routed correctly so a handler for * its type was not registered. * * c. An interrupt of a type was routed correctly to EL3, but was * deasserted before its pending state could be read. Another * interrupt of a different type pended at the same time and its * type was reported as pending instead. However, a handler for this * type was not registered. * * a. and b. can only happen due to a programming error. The * occurrence of c. could be beyond the control of Trusted Firmware. * It makes sense to return from this exception instead of reporting an * error. */ bl get_interrupt_type_handler cbz x0, interrupt_exit_\label mov x21, x0 mov x0, #INTR_ID_UNAVAILABLE /* Set the current security state in the 'flags' parameter */ mrs x2, scr_el3 ubfx x1, x2, #0, #1 /* Restore the reference to the 'handle' i.e. SP_EL3 */ mov x2, x20 /* x3 will point to a cookie (not used now) */ mov x3, xzr /* Call the interrupt type handler */ blr x21 interrupt_exit_\label: /* Return from exception, possibly in a different security state */ b el3_exit .endm vector_base runtime_exceptions /* --------------------------------------------------------------------- * Current EL with SP_EL0 : 0x0 - 0x200 * --------------------------------------------------------------------- */ vector_entry sync_exception_sp_el0 #ifdef MONITOR_TRAPS stp x29, x30, [sp, #-16]! mrs x30, esr_el3 ubfx x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH /* Check for BRK */ cmp x30, #EC_BRK b.eq brk_handler ldp x29, x30, [sp], #16 #endif /* MONITOR_TRAPS */ /* We don't expect any synchronous exceptions from EL3 */ b report_unhandled_exception end_vector_entry sync_exception_sp_el0 vector_entry irq_sp_el0 /* * EL3 code is non-reentrant. Any asynchronous exception is a serious * error. Loop infinitely. */ b report_unhandled_interrupt end_vector_entry irq_sp_el0 vector_entry fiq_sp_el0 b report_unhandled_interrupt end_vector_entry fiq_sp_el0 vector_entry serror_sp_el0 no_ret plat_handle_el3_ea end_vector_entry serror_sp_el0 /* --------------------------------------------------------------------- * Current EL with SP_ELx: 0x200 - 0x400 * --------------------------------------------------------------------- */ vector_entry sync_exception_sp_elx /* * This exception will trigger if anything went wrong during a previous * exception entry or exit or while handling an earlier unexpected * synchronous exception. There is a high probability that SP_EL3 is * corrupted. */ b report_unhandled_exception end_vector_entry sync_exception_sp_elx vector_entry irq_sp_elx b report_unhandled_interrupt end_vector_entry irq_sp_elx vector_entry fiq_sp_elx b report_unhandled_interrupt end_vector_entry fiq_sp_elx vector_entry serror_sp_elx #if !RAS_EXTENSION check_if_serror_from_EL3 #endif no_ret plat_handle_el3_ea end_vector_entry serror_sp_elx /* --------------------------------------------------------------------- * Lower EL using AArch64 : 0x400 - 0x600 * --------------------------------------------------------------------- */ vector_entry sync_exception_aarch64 /* * This exception vector will be the entry point for SMCs and traps * that are unhandled at lower ELs most commonly. SP_EL3 should point * to a valid cpu context where the general purpose and system register * state can be saved. */ apply_at_speculative_wa check_and_unmask_ea handle_sync_exception end_vector_entry sync_exception_aarch64 vector_entry irq_aarch64 apply_at_speculative_wa check_and_unmask_ea handle_interrupt_exception irq_aarch64 end_vector_entry irq_aarch64 vector_entry fiq_aarch64 apply_at_speculative_wa check_and_unmask_ea handle_interrupt_exception fiq_aarch64 end_vector_entry fiq_aarch64 vector_entry serror_aarch64 apply_at_speculative_wa #if RAS_EXTENSION msr daifclr, #DAIF_ABT_BIT b enter_lower_el_async_ea #else handle_async_ea #endif end_vector_entry serror_aarch64 /* --------------------------------------------------------------------- * Lower EL using AArch32 : 0x600 - 0x800 * --------------------------------------------------------------------- */ vector_entry sync_exception_aarch32 /* * This exception vector will be the entry point for SMCs and traps * that are unhandled at lower ELs most commonly. SP_EL3 should point * to a valid cpu context where the general purpose and system register * state can be saved. */ apply_at_speculative_wa check_and_unmask_ea handle_sync_exception end_vector_entry sync_exception_aarch32 vector_entry irq_aarch32 apply_at_speculative_wa check_and_unmask_ea handle_interrupt_exception irq_aarch32 end_vector_entry irq_aarch32 vector_entry fiq_aarch32 apply_at_speculative_wa check_and_unmask_ea handle_interrupt_exception fiq_aarch32 end_vector_entry fiq_aarch32 vector_entry serror_aarch32 apply_at_speculative_wa #if RAS_EXTENSION msr daifclr, #DAIF_ABT_BIT b enter_lower_el_async_ea #else handle_async_ea #endif end_vector_entry serror_aarch32 #ifdef MONITOR_TRAPS .section .rodata.brk_string, "aS" brk_location: .asciz "Error at instruction 0x" brk_message: .asciz "Unexpected BRK instruction with value 0x" #endif /* MONITOR_TRAPS */ /* --------------------------------------------------------------------- * The following code handles secure monitor calls. * Depending upon the execution state from where the SMC has been * invoked, it frees some general purpose registers to perform the * remaining tasks. They involve finding the runtime service handler * that is the target of the SMC & switching to runtime stacks (SP_EL0) * before calling the handler. * * Note that x30 has been explicitly saved and can be used here * --------------------------------------------------------------------- */ func smc_handler smc_handler32: /* Check whether aarch32 issued an SMC64 */ tbnz x0, #FUNCID_CC_SHIFT, smc_prohibited smc_handler64: /* NOTE: The code below must preserve x0-x4 */ /* * Save general purpose and ARMv8.3-PAuth registers (if enabled). * If Secure Cycle Counter is not disabled in MDCR_EL3 when * ARMv8.5-PMU is implemented, save PMCR_EL0 and disable Cycle Counter. */ bl save_gp_pmcr_pauth_regs #if ENABLE_PAUTH /* Load and program APIAKey firmware key */ bl pauth_load_bl31_apiakey #endif /* * Populate the parameters for the SMC handler. * We already have x0-x4 in place. x5 will point to a cookie (not used * now). x6 will point to the context structure (SP_EL3) and x7 will * contain flags we need to pass to the handler. */ mov x5, xzr mov x6, sp /* * Restore the saved C runtime stack value which will become the new * SP_EL0 i.e. EL3 runtime stack. It was saved in the 'cpu_context' * structure prior to the last ERET from EL3. */ ldr x12, [x6, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP] /* Switch to SP_EL0 */ msr spsel, #MODE_SP_EL0 /* * Save the SPSR_EL3, ELR_EL3, & SCR_EL3 in case there is a world * switch during SMC handling. * TODO: Revisit if all system registers can be saved later. */ mrs x16, spsr_el3 mrs x17, elr_el3 mrs x18, scr_el3 stp x16, x17, [x6, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3] str x18, [x6, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3] #if ENABLE_RME /* Copy SCR_EL3.NSE bit to the flag to indicate caller's security */ ubfx x7, x18, #SCR_NSE_SHIFT, 1 /* Shift copied SCR_EL3.NSE bit by 1 to create space for SCR_EL3.NS bit */ lsl x7, x7, #1 #endif /* ENABLE_RME */ /* Copy SCR_EL3.NS bit to the flag to indicate caller's security */ bfi x7, x18, #0, #1 mov sp, x12 /* Get the unique owning entity number */ ubfx x16, x0, #FUNCID_OEN_SHIFT, #FUNCID_OEN_WIDTH ubfx x15, x0, #FUNCID_TYPE_SHIFT, #FUNCID_TYPE_WIDTH orr x16, x16, x15, lsl #FUNCID_OEN_WIDTH /* Load descriptor index from array of indices */ adrp x14, rt_svc_descs_indices add x14, x14, :lo12:rt_svc_descs_indices ldrb w15, [x14, x16] /* Any index greater than 127 is invalid. Check bit 7. */ tbnz w15, 7, smc_unknown /* * Get the descriptor using the index * x11 = (base + off), w15 = index * * handler = (base + off) + (index << log2(size)) */ adr x11, (__RT_SVC_DESCS_START__ + RT_SVC_DESC_HANDLE) lsl w10, w15, #RT_SVC_SIZE_LOG2 ldr x15, [x11, w10, uxtw] /* * Call the Secure Monitor Call handler and then drop directly into * el3_exit() which will program any remaining architectural state * prior to issuing the ERET to the desired lower EL. */ #if DEBUG cbz x15, rt_svc_fw_critical_error #endif blr x15 b el3_exit smc_unknown: /* * Unknown SMC call. Populate return value with SMC_UNK and call * el3_exit() which will restore the remaining architectural state * i.e., SYS, GP and PAuth registers(if any) prior to issuing the ERET * to the desired lower EL. */ mov x0, #SMC_UNK str x0, [x6, #CTX_GPREGS_OFFSET + CTX_GPREG_X0] b el3_exit smc_prohibited: restore_ptw_el1_sys_regs ldp x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28] ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] mov x0, #SMC_UNK exception_return #if DEBUG rt_svc_fw_critical_error: /* Switch to SP_ELx */ msr spsel, #MODE_SP_ELX no_ret report_unhandled_exception #endif endfunc smc_handler /* --------------------------------------------------------------------- * The following code handles exceptions caused by BRK instructions. * Following a BRK instruction, the only real valid cause of action is * to print some information and panic, as the code that caused it is * likely in an inconsistent internal state. * * This is initially intended to be used in conjunction with * __builtin_trap. * --------------------------------------------------------------------- */ #ifdef MONITOR_TRAPS func brk_handler /* Extract the ISS */ mrs x10, esr_el3 ubfx x10, x10, #ESR_ISS_SHIFT, #ESR_ISS_LENGTH /* Ensure the console is initialized */ bl plat_crash_console_init adr x4, brk_location bl asm_print_str mrs x4, elr_el3 bl asm_print_hex bl asm_print_newline adr x4, brk_message bl asm_print_str mov x4, x10 mov x5, #28 bl asm_print_hex_bits bl asm_print_newline no_ret plat_panic_handler endfunc brk_handler #endif /* MONITOR_TRAPS */