504 lines
14 KiB
ArmAsm
504 lines
14 KiB
ArmAsm
/*
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* Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <platform_def.h>
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#include <arch.h>
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#include <asm_macros.S>
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#include <bl31/ea_handle.h>
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#include <bl31/interrupt_mgmt.h>
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#include <common/runtime_svc.h>
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#include <context.h>
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#include <lib/el3_runtime/cpu_data.h>
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#include <lib/smccc.h>
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.globl runtime_exceptions
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.globl sync_exception_sp_el0
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.globl irq_sp_el0
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.globl fiq_sp_el0
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.globl serror_sp_el0
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.globl sync_exception_sp_elx
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.globl irq_sp_elx
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.globl fiq_sp_elx
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.globl serror_sp_elx
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.globl sync_exception_aarch64
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.globl irq_aarch64
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.globl fiq_aarch64
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.globl serror_aarch64
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.globl sync_exception_aarch32
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.globl irq_aarch32
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.globl fiq_aarch32
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.globl serror_aarch32
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/*
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* Macro that prepares entry to EL3 upon taking an exception.
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*
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* With RAS_EXTENSION, this macro synchronizes pending errors with an ESB
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* instruction. When an error is thus synchronized, the handling is
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* delegated to platform EA handler.
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*
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* Without RAS_EXTENSION, this macro just saves x30, and unmasks
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* Asynchronous External Aborts.
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*/
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.macro check_and_unmask_ea
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#if RAS_EXTENSION
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/* Synchronize pending External Aborts */
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esb
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/* Unmask the SError interrupt */
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msr daifclr, #DAIF_ABT_BIT
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/*
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* Explicitly save x30 so as to free up a register and to enable
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* branching
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*/
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str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
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/* Check for SErrors synchronized by the ESB instruction */
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mrs x30, DISR_EL1
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tbz x30, #DISR_A_BIT, 1f
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/*
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* Save general purpose and ARMv8.3-PAuth registers (if enabled).
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* If Secure Cycle Counter is not disabled in MDCR_EL3 when
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* ARMv8.5-PMU is implemented, save PMCR_EL0 and disable Cycle Counter.
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*/
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bl save_gp_pmcr_pauth_regs
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bl handle_lower_el_ea_esb
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/* Restore general purpose, PMCR_EL0 and ARMv8.3-PAuth registers */
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bl restore_gp_pmcr_pauth_regs
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1:
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#else
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/* Unmask the SError interrupt */
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msr daifclr, #DAIF_ABT_BIT
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str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
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#endif
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.endm
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/* ---------------------------------------------------------------------
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* This macro handles Synchronous exceptions.
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* Only SMC exceptions are supported.
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* ---------------------------------------------------------------------
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*/
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.macro handle_sync_exception
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#if ENABLE_RUNTIME_INSTRUMENTATION
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/*
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* Read the timestamp value and store it in per-cpu data. The value
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* will be extracted from per-cpu data by the C level SMC handler and
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* saved to the PMF timestamp region.
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*/
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mrs x30, cntpct_el0
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str x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X29]
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mrs x29, tpidr_el3
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str x30, [x29, #CPU_DATA_PMF_TS0_OFFSET]
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ldr x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X29]
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#endif
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mrs x30, esr_el3
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ubfx x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH
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/* Handle SMC exceptions separately from other synchronous exceptions */
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cmp x30, #EC_AARCH32_SMC
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b.eq smc_handler32
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cmp x30, #EC_AARCH64_SMC
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b.eq smc_handler64
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/* Synchronous exceptions other than the above are assumed to be EA */
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ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
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b enter_lower_el_sync_ea
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.endm
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/* ---------------------------------------------------------------------
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* This macro handles FIQ or IRQ interrupts i.e. EL3, S-EL1 and NS
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* interrupts.
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* ---------------------------------------------------------------------
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*/
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.macro handle_interrupt_exception label
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/*
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* Save general purpose and ARMv8.3-PAuth registers (if enabled).
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* If Secure Cycle Counter is not disabled in MDCR_EL3 when
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* ARMv8.5-PMU is implemented, save PMCR_EL0 and disable Cycle Counter.
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*/
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bl save_gp_pmcr_pauth_regs
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#if ENABLE_PAUTH
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/* Load and program APIAKey firmware key */
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bl pauth_load_bl31_apiakey
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#endif
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/* Save the EL3 system registers needed to return from this exception */
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mrs x0, spsr_el3
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mrs x1, elr_el3
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stp x0, x1, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
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/* Switch to the runtime stack i.e. SP_EL0 */
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ldr x2, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
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mov x20, sp
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msr spsel, #MODE_SP_EL0
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mov sp, x2
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/*
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* Find out whether this is a valid interrupt type.
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* If the interrupt controller reports a spurious interrupt then return
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* to where we came from.
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*/
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bl plat_ic_get_pending_interrupt_type
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cmp x0, #INTR_TYPE_INVAL
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b.eq interrupt_exit_\label
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/*
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* Get the registered handler for this interrupt type.
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* A NULL return value could be 'cause of the following conditions:
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*
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* a. An interrupt of a type was routed correctly but a handler for its
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* type was not registered.
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*
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* b. An interrupt of a type was not routed correctly so a handler for
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* its type was not registered.
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*
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* c. An interrupt of a type was routed correctly to EL3, but was
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* deasserted before its pending state could be read. Another
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* interrupt of a different type pended at the same time and its
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* type was reported as pending instead. However, a handler for this
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* type was not registered.
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*
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* a. and b. can only happen due to a programming error. The
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* occurrence of c. could be beyond the control of Trusted Firmware.
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* It makes sense to return from this exception instead of reporting an
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* error.
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*/
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bl get_interrupt_type_handler
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cbz x0, interrupt_exit_\label
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mov x21, x0
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mov x0, #INTR_ID_UNAVAILABLE
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/* Set the current security state in the 'flags' parameter */
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mrs x2, scr_el3
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ubfx x1, x2, #0, #1
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/* Restore the reference to the 'handle' i.e. SP_EL3 */
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mov x2, x20
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/* x3 will point to a cookie (not used now) */
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mov x3, xzr
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/* Call the interrupt type handler */
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blr x21
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interrupt_exit_\label:
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/* Return from exception, possibly in a different security state */
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b el3_exit
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.endm
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vector_base runtime_exceptions
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/* ---------------------------------------------------------------------
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* Current EL with SP_EL0 : 0x0 - 0x200
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* ---------------------------------------------------------------------
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*/
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vector_entry sync_exception_sp_el0
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#ifdef MONITOR_TRAPS
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stp x29, x30, [sp, #-16]!
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mrs x30, esr_el3
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ubfx x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH
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/* Check for BRK */
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cmp x30, #EC_BRK
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b.eq brk_handler
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ldp x29, x30, [sp], #16
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#endif /* MONITOR_TRAPS */
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/* We don't expect any synchronous exceptions from EL3 */
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b report_unhandled_exception
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end_vector_entry sync_exception_sp_el0
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vector_entry irq_sp_el0
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/*
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* EL3 code is non-reentrant. Any asynchronous exception is a serious
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* error. Loop infinitely.
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*/
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b report_unhandled_interrupt
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end_vector_entry irq_sp_el0
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vector_entry fiq_sp_el0
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b report_unhandled_interrupt
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end_vector_entry fiq_sp_el0
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vector_entry serror_sp_el0
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no_ret plat_handle_el3_ea
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end_vector_entry serror_sp_el0
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/* ---------------------------------------------------------------------
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* Current EL with SP_ELx: 0x200 - 0x400
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* ---------------------------------------------------------------------
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*/
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vector_entry sync_exception_sp_elx
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/*
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* This exception will trigger if anything went wrong during a previous
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* exception entry or exit or while handling an earlier unexpected
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* synchronous exception. There is a high probability that SP_EL3 is
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* corrupted.
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*/
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b report_unhandled_exception
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end_vector_entry sync_exception_sp_elx
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vector_entry irq_sp_elx
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b report_unhandled_interrupt
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end_vector_entry irq_sp_elx
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vector_entry fiq_sp_elx
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b report_unhandled_interrupt
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end_vector_entry fiq_sp_elx
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vector_entry serror_sp_elx
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no_ret plat_handle_el3_ea
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end_vector_entry serror_sp_elx
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/* ---------------------------------------------------------------------
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* Lower EL using AArch64 : 0x400 - 0x600
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* ---------------------------------------------------------------------
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*/
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vector_entry sync_exception_aarch64
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/*
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* This exception vector will be the entry point for SMCs and traps
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* that are unhandled at lower ELs most commonly. SP_EL3 should point
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* to a valid cpu context where the general purpose and system register
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* state can be saved.
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*/
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check_and_unmask_ea
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handle_sync_exception
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end_vector_entry sync_exception_aarch64
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vector_entry irq_aarch64
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check_and_unmask_ea
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handle_interrupt_exception irq_aarch64
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end_vector_entry irq_aarch64
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vector_entry fiq_aarch64
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check_and_unmask_ea
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handle_interrupt_exception fiq_aarch64
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end_vector_entry fiq_aarch64
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vector_entry serror_aarch64
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msr daifclr, #DAIF_ABT_BIT
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b enter_lower_el_async_ea
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end_vector_entry serror_aarch64
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/* ---------------------------------------------------------------------
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* Lower EL using AArch32 : 0x600 - 0x800
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* ---------------------------------------------------------------------
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*/
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vector_entry sync_exception_aarch32
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/*
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* This exception vector will be the entry point for SMCs and traps
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* that are unhandled at lower ELs most commonly. SP_EL3 should point
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* to a valid cpu context where the general purpose and system register
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* state can be saved.
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*/
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check_and_unmask_ea
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handle_sync_exception
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end_vector_entry sync_exception_aarch32
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vector_entry irq_aarch32
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check_and_unmask_ea
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handle_interrupt_exception irq_aarch32
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end_vector_entry irq_aarch32
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vector_entry fiq_aarch32
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check_and_unmask_ea
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handle_interrupt_exception fiq_aarch32
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end_vector_entry fiq_aarch32
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vector_entry serror_aarch32
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msr daifclr, #DAIF_ABT_BIT
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b enter_lower_el_async_ea
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end_vector_entry serror_aarch32
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#ifdef MONITOR_TRAPS
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.section .rodata.brk_string, "aS"
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brk_location:
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.asciz "Error at instruction 0x"
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brk_message:
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.asciz "Unexpected BRK instruction with value 0x"
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#endif /* MONITOR_TRAPS */
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/* ---------------------------------------------------------------------
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* The following code handles secure monitor calls.
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* Depending upon the execution state from where the SMC has been
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* invoked, it frees some general purpose registers to perform the
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* remaining tasks. They involve finding the runtime service handler
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* that is the target of the SMC & switching to runtime stacks (SP_EL0)
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* before calling the handler.
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*
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* Note that x30 has been explicitly saved and can be used here
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* ---------------------------------------------------------------------
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*/
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func smc_handler
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smc_handler32:
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/* Check whether aarch32 issued an SMC64 */
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tbnz x0, #FUNCID_CC_SHIFT, smc_prohibited
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smc_handler64:
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/* NOTE: The code below must preserve x0-x4 */
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/*
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* Save general purpose and ARMv8.3-PAuth registers (if enabled).
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* If Secure Cycle Counter is not disabled in MDCR_EL3 when
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* ARMv8.5-PMU is implemented, save PMCR_EL0 and disable Cycle Counter.
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*/
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bl save_gp_pmcr_pauth_regs
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#if ENABLE_PAUTH
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/* Load and program APIAKey firmware key */
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bl pauth_load_bl31_apiakey
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#endif
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/*
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* Populate the parameters for the SMC handler.
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* We already have x0-x4 in place. x5 will point to a cookie (not used
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* now). x6 will point to the context structure (SP_EL3) and x7 will
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* contain flags we need to pass to the handler.
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*/
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mov x5, xzr
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mov x6, sp
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/*
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* Restore the saved C runtime stack value which will become the new
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* SP_EL0 i.e. EL3 runtime stack. It was saved in the 'cpu_context'
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* structure prior to the last ERET from EL3.
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*/
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ldr x12, [x6, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
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/* Switch to SP_EL0 */
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msr spsel, #MODE_SP_EL0
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/*
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* Save the SPSR_EL3, ELR_EL3, & SCR_EL3 in case there is a world
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* switch during SMC handling.
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* TODO: Revisit if all system registers can be saved later.
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*/
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mrs x16, spsr_el3
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mrs x17, elr_el3
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mrs x18, scr_el3
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stp x16, x17, [x6, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
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str x18, [x6, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
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/* Copy SCR_EL3.NS bit to the flag to indicate caller's security */
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bfi x7, x18, #0, #1
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mov sp, x12
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/* Get the unique owning entity number */
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ubfx x16, x0, #FUNCID_OEN_SHIFT, #FUNCID_OEN_WIDTH
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ubfx x15, x0, #FUNCID_TYPE_SHIFT, #FUNCID_TYPE_WIDTH
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orr x16, x16, x15, lsl #FUNCID_OEN_WIDTH
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/* Load descriptor index from array of indices */
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adr x14, rt_svc_descs_indices
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ldrb w15, [x14, x16]
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/* Any index greater than 127 is invalid. Check bit 7. */
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tbnz w15, 7, smc_unknown
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/*
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* Get the descriptor using the index
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* x11 = (base + off), w15 = index
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*
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* handler = (base + off) + (index << log2(size))
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*/
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adr x11, (__RT_SVC_DESCS_START__ + RT_SVC_DESC_HANDLE)
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lsl w10, w15, #RT_SVC_SIZE_LOG2
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ldr x15, [x11, w10, uxtw]
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/*
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* Call the Secure Monitor Call handler and then drop directly into
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* el3_exit() which will program any remaining architectural state
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* prior to issuing the ERET to the desired lower EL.
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*/
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#if DEBUG
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cbz x15, rt_svc_fw_critical_error
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#endif
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blr x15
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b el3_exit
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smc_unknown:
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/*
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* Unknown SMC call. Populate return value with SMC_UNK and call
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* el3_exit() which will restore the remaining architectural state
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* i.e., SYS, GP and PAuth registers(if any) prior to issuing the ERET
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* to the desired lower EL.
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*/
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mov x0, #SMC_UNK
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str x0, [x6, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
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b el3_exit
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smc_prohibited:
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ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
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mov x0, #SMC_UNK
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eret
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#if DEBUG
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rt_svc_fw_critical_error:
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/* Switch to SP_ELx */
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msr spsel, #MODE_SP_ELX
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no_ret report_unhandled_exception
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#endif
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endfunc smc_handler
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/* ---------------------------------------------------------------------
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* The following code handles exceptions caused by BRK instructions.
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* Following a BRK instruction, the only real valid cause of action is
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* to print some information and panic, as the code that caused it is
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* likely in an inconsistent internal state.
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*
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* This is initially intended to be used in conjunction with
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* __builtin_trap.
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* ---------------------------------------------------------------------
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*/
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#ifdef MONITOR_TRAPS
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func brk_handler
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/* Extract the ISS */
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mrs x10, esr_el3
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ubfx x10, x10, #ESR_ISS_SHIFT, #ESR_ISS_LENGTH
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/* Ensure the console is initialized */
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bl plat_crash_console_init
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adr x4, brk_location
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bl asm_print_str
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mrs x4, elr_el3
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bl asm_print_hex
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bl asm_print_newline
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adr x4, brk_message
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bl asm_print_str
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mov x4, x10
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mov x5, #28
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bl asm_print_hex_bits
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bl asm_print_newline
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no_ret plat_panic_handler
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endfunc brk_handler
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#endif /* MONITOR_TRAPS */
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