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/*
* Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of ARM nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <arch.h>
#include <asm_macros.S>
#include <context.h>
#include <cpu_data.h>
#include <interrupt_mgmt.h>
#include <platform_def.h>
#include <runtime_svc.h>
.globl runtime_exceptions
/* ---------------------------------------------------------------------
* This macro handles Synchronous exceptions.
* Only SMC exceptions are supported.
* ---------------------------------------------------------------------
*/
.macro handle_sync_exception
/* Enable the SError interrupt */
msr daifclr, #DAIF_ABT_BIT
str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
#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
/* Other kinds of synchronous exceptions are not handled */
no_ret report_unhandled_exception
.endm
/* ---------------------------------------------------------------------
* This macro handles FIQ or IRQ interrupts i.e. EL3, S-EL1 and NS
* interrupts.
* ---------------------------------------------------------------------
*/
.macro handle_interrupt_exception label
/* Enable the SError interrupt */
msr daifclr, #DAIF_ABT_BIT
str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
bl save_gp_registers
/* 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, #0
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
.macro save_x18_to_x29_sp_el0
stp x18, x19, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
stp x20, x21, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X20]
stp x22, x23, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X22]
stp x24, x25, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X24]
stp x26, x27, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X26]
stp x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28]
mrs x18, sp_el0
str x18, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_SP_EL0]
.endm
vector_base runtime_exceptions
/* ---------------------------------------------------------------------
* Current EL with SP_EL0 : 0x0 - 0x200
* ---------------------------------------------------------------------
*/
vector_entry sync_exception_sp_el0
/* We don't expect any synchronous exceptions from EL3 */
no_ret report_unhandled_exception
check_vector_size sync_exception_sp_el0
vector_entry irq_sp_el0
/*
* EL3 code is non-reentrant. Any asynchronous exception is a serious
* error. Loop infinitely.
*/
no_ret report_unhandled_interrupt
check_vector_size irq_sp_el0
vector_entry fiq_sp_el0
no_ret report_unhandled_interrupt
check_vector_size fiq_sp_el0
vector_entry serror_sp_el0
no_ret report_unhandled_exception
check_vector_size 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.
*/
no_ret report_unhandled_exception
check_vector_size sync_exception_sp_elx
vector_entry irq_sp_elx
no_ret report_unhandled_interrupt
check_vector_size irq_sp_elx
vector_entry fiq_sp_elx
no_ret report_unhandled_interrupt
check_vector_size fiq_sp_elx
vector_entry serror_sp_elx
no_ret report_unhandled_exception
check_vector_size 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.
*/
handle_sync_exception
check_vector_size sync_exception_aarch64
vector_entry irq_aarch64
handle_interrupt_exception irq_aarch64
check_vector_size irq_aarch64
vector_entry fiq_aarch64
handle_interrupt_exception fiq_aarch64
check_vector_size fiq_aarch64
vector_entry serror_aarch64
/*
* SError exceptions from lower ELs are not currently supported.
* Report their occurrence.
*/
no_ret report_unhandled_exception
check_vector_size 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.
*/
handle_sync_exception
check_vector_size sync_exception_aarch32
vector_entry irq_aarch32
handle_interrupt_exception irq_aarch32
check_vector_size irq_aarch32
vector_entry fiq_aarch32
handle_interrupt_exception fiq_aarch32
check_vector_size fiq_aarch32
vector_entry serror_aarch32
/*
* SError exceptions from lower ELs are not currently supported.
* Report their occurrence.
*/
no_ret report_unhandled_exception
check_vector_size serror_aarch32
/* ---------------------------------------------------------------------
* 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
/*
* Since we're are coming from aarch32, x8-x18 need to be saved as per
* SMC32 calling convention. If a lower EL in aarch64 is making an
* SMC32 call then it must have saved x8-x17 already therein.
*/
stp x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
stp x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
stp x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
stp x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
stp x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
/* x4-x7, x18, sp_el0 are saved below */
smc_handler64:
/*
* 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 Hence save x5-x7.
*
* Note: x4 only needs to be preserved for AArch32 callers but we do it
* for AArch64 callers as well for convenience
*/
stp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
stp x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
/* Save rest of the gpregs and sp_el0*/
save_x18_to_x29_sp_el0
mov x5, xzr
mov x6, sp
/* 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
adr x11, (__RT_SVC_DESCS_START__ + RT_SVC_DESC_HANDLE)
/* Load descriptor index from array of indices */
adr x14, rt_svc_descs_indices
ldrb w15, [x14, x16]
/*
* 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]
/*
* Any index greater than 127 is invalid. Check bit 7 for
* a valid index
*/
tbnz w15, 7, smc_unknown
/* Switch to SP_EL0 */
msr spsel, #0
/*
* Get the descriptor using the index
* x11 = (base + off), x15 = index
*
* handler = (base + off) + (index << log2(size))
*/
lsl w10, w15, #RT_SVC_SIZE_LOG2
ldr x15, [x11, w10, uxtw]
/*
* 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]
/* Copy SCR_EL3.NS bit to the flag to indicate caller's security */
bfi x7, x18, #0, #1
mov sp, x12
/*
* 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:
/*
* Here we restore x4-x18 regardless of where we came from. AArch32
* callers will find the registers contents unchanged, but AArch64
* callers will find the registers modified (with stale earlier NS
* content). Either way, we aren't leaking any secure information
* through them.
*/
mov w0, #SMC_UNK
b restore_gp_registers_callee_eret
smc_prohibited:
ldr x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
mov w0, #SMC_UNK
eret
rt_svc_fw_critical_error:
/* Switch to SP_ELx */
msr spsel, #1
no_ret report_unhandled_exception
endfunc smc_handler