diff --git a/bl31/aarch64/ea_delegate.S b/bl31/aarch64/ea_delegate.S new file mode 100644 index 0000000..dce1f5a --- /dev/null +++ b/bl31/aarch64/ea_delegate.S @@ -0,0 +1,163 @@ +/* + * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + + +#include +#include +#include + + + .globl handle_lower_el_ea_esb + .globl enter_lower_el_sync_ea + .globl enter_lower_el_async_ea + + +/* + * Function to delegate External Aborts synchronized by ESB instruction at EL3 + * vector entry. This function assumes GP registers x0-x29 have been saved, and + * are available for use. It delegates the handling of the EA to platform + * handler, and returns only upon successfully handling the EA; otherwise + * panics. On return from this function, the original exception handler is + * expected to resume. + */ +func handle_lower_el_ea_esb + mov x0, #ERROR_EA_ESB + mrs x1, DISR_EL1 + b ea_proceed +endfunc handle_lower_el_ea_esb + + +/* + * This function forms the tail end of Synchronous Exception entry from lower + * EL, and expects to handle only Synchronous External Aborts from lower EL. If + * any other kind of exception is detected, then this function reports unhandled + * exception. + * + * Since it's part of exception vector, this function doesn't expect any GP + * registers to have been saved. It delegates the handling of the EA to platform + * handler, and upon successfully handling the EA, exits EL3; otherwise panics. + */ +func enter_lower_el_sync_ea + /* + * Explicitly save x30 so as to free up a register and to enable + * branching. + */ + str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] + + mrs x30, esr_el3 + ubfx x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH + + /* Check for I/D aborts from lower EL */ + cmp x30, #EC_IABORT_LOWER_EL + b.eq 1f + + cmp x30, #EC_DABORT_LOWER_EL + b.ne 2f + +1: + /* Test for EA bit in the instruction syndrome */ + mrs x30, esr_el3 + tbz x30, #ESR_ISS_EABORT_EA_BIT, 2f + + /* Save GP registers */ + bl save_gp_registers + + /* Setup exception class and syndrome arguments for platform handler */ + mov x0, #ERROR_EA_SYNC + mrs x1, esr_el3 + adr x30, el3_exit + b ea_proceed + +2: + /* Synchronous exceptions other than the above are assumed to be EA */ + ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] + no_ret report_unhandled_exception +endfunc enter_lower_el_sync_ea + + +/* + * This function handles SErrors from lower ELs. + * + * Since it's part of exception vector, this function doesn't expect any GP + * registers to have been saved. It delegates the handling of the EA to platform + * handler, and upon successfully handling the EA, exits EL3; otherwise panics. + */ +func enter_lower_el_async_ea + /* + * Explicitly save x30 so as to free up a register and to enable + * branching + */ + str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] + + /* Save GP registers */ + bl save_gp_registers + + /* Setup exception class and syndrome arguments for platform handler */ + mov x0, #ERROR_EA_ASYNC + mrs x1, esr_el3 + adr x30, el3_exit + b ea_proceed +endfunc enter_lower_el_async_ea + + +/* + * Delegate External Abort handling to platform's EA handler. This function + * assumes that all GP registers have been saved by the caller. + * + * x0: EA reason + * x1: EA syndrome + */ +func ea_proceed + /* Save EL3 state */ + mrs x2, spsr_el3 + mrs x3, elr_el3 + stp x2, x3, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3] + + /* + * Save ESR as handling might involve lower ELs, and returning back to + * EL3 from there would trample the original ESR. + */ + mrs x4, scr_el3 + mrs x5, esr_el3 + stp x4, x5, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3] + + /* + * Setup rest of arguments, and call platform External Abort handler. + * + * x0: EA reason (already in place) + * x1: Exception syndrome (already in place). + * x2: Cookie (unused for now). + * x3: Context pointer. + * x4: Flags (security state from SCR for now). + */ + mov x2, xzr + mov x3, sp + ubfx x4, x4, #0, #1 + + /* Switch to runtime stack */ + ldr x5, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP] + msr spsel, #0 + mov sp, x5 + + mov x29, x30 + bl plat_ea_handler + mov x30, x29 + + /* Make SP point to context */ + msr spsel, #1 + + /* Restore EL3 state */ + ldp x1, x2, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3] + msr spsr_el3, x1 + msr elr_el3, x2 + + /* Restore ESR_EL3 and SCR_EL3 */ + ldp x3, x4, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3] + msr scr_el3, x3 + msr esr_el3, x4 + + ret +endfunc ea_proceed diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S index 12f9f10..ff77597 100644 --- a/bl31/aarch64/runtime_exceptions.S +++ b/bl31/aarch64/runtime_exceptions.S @@ -66,9 +66,7 @@ /* Save GP registers and restore them afterwards */ bl save_gp_registers - mov x0, #ERROR_EA_ESB - mrs x1, DISR_EL1 - bl delegate_ea + bl handle_lower_el_ea_esb bl restore_gp_registers 1: @@ -80,27 +78,6 @@ #endif .endm - /* - * Handle External Abort by delegating to the platform's EA handler. - * Once the platform handler returns, the macro exits EL3 and returns to - * where the abort was taken from. - * - * This macro assumes that x30 is available for use. - * - * 'abort_type' is a constant passed to the platform handler, indicating - * the cause of the External Abort. - */ - .macro handle_ea abort_type - /* Save GP registers */ - bl save_gp_registers - - /* Setup exception class and syndrome arguments for platform handler */ - mov x0, \abort_type - mrs x1, esr_el3 - adr x30, el3_exit - b delegate_ea - .endm - /* --------------------------------------------------------------------- * This macro handles Synchronous exceptions. * Only SMC exceptions are supported. @@ -130,23 +107,9 @@ cmp x30, #EC_AARCH64_SMC b.eq smc_handler64 - /* Check for I/D aborts from lower EL */ - cmp x30, #EC_IABORT_LOWER_EL - b.eq 1f - - cmp x30, #EC_DABORT_LOWER_EL - b.ne 2f - -1: - /* Test for EA bit in the instruction syndrome */ - mrs x30, esr_el3 - tbz x30, #ESR_ISS_EABORT_EA_BIT, 2f - handle_ea #ERROR_EA_SYNC - -2: - /* Other kinds of synchronous exceptions are not handled */ + /* Synchronous exceptions other than the above are assumed to be EA */ ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR] - b report_unhandled_exception + b enter_lower_el_sync_ea .endm @@ -306,13 +269,7 @@ vector_entry serror_aarch64 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] - handle_ea #ERROR_EA_ASYNC + b enter_lower_el_async_ea end_vector_entry serror_aarch64 /* --------------------------------------------------------------------- @@ -342,13 +299,7 @@ vector_entry serror_aarch32 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] - handle_ea #ERROR_EA_ASYNC + b enter_lower_el_async_ea end_vector_entry serror_aarch32 @@ -525,62 +476,3 @@ msr spsel, #1 no_ret report_unhandled_exception endfunc smc_handler - -/* - * Delegate External Abort handling to platform's EA handler. This function - * assumes that all GP registers have been saved by the caller. - * - * x0: EA reason - * x1: EA syndrome - */ -func delegate_ea - /* Save EL3 state */ - mrs x2, spsr_el3 - mrs x3, elr_el3 - stp x2, x3, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3] - - /* - * Save ESR as handling might involve lower ELs, and returning back to - * EL3 from there would trample the original ESR. - */ - mrs x4, scr_el3 - mrs x5, esr_el3 - stp x4, x5, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3] - - /* - * Setup rest of arguments, and call platform External Abort handler. - * - * x0: EA reason (already in place) - * x1: Exception syndrome (already in place). - * x2: Cookie (unused for now). - * x3: Context pointer. - * x4: Flags (security state from SCR for now). - */ - mov x2, xzr - mov x3, sp - ubfx x4, x4, #0, #1 - - /* Switch to runtime stack */ - ldr x5, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP] - msr spsel, #0 - mov sp, x5 - - mov x29, x30 - bl plat_ea_handler - mov x30, x29 - - /* Make SP point to context */ - msr spsel, #1 - - /* Restore EL3 state */ - ldp x1, x2, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3] - msr spsr_el3, x1 - msr elr_el3, x2 - - /* Restore ESR_EL3 and SCR_EL3 */ - ldp x3, x4, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3] - msr scr_el3, x3 - msr esr_el3, x4 - - ret -endfunc delegate_ea diff --git a/bl31/bl31.mk b/bl31/bl31.mk index 307ddab..bff9653 100644 --- a/bl31/bl31.mk +++ b/bl31/bl31.mk @@ -19,6 +19,7 @@ bl31/interrupt_mgmt.c \ bl31/aarch64/bl31_entrypoint.S \ bl31/aarch64/crash_reporting.S \ + bl31/aarch64/ea_delegate.S \ bl31/aarch64/runtime_exceptions.S \ bl31/bl31_context_mgmt.c \ common/runtime_svc.c \