freebsd-nq/sys/arm64/arm64/exception.S
Andrew Turner 90257a2b6c Skip restoring more registers when returning from an exception taken in
the kernel. These registers are all callee saved, and as such will be
restored before returning to the exception handler.

Userland still needs these registers to be restored as they may be changed
by the kernel and we don't currently track these places.
2015-12-14 10:06:01 +00:00

222 lines
5.3 KiB
ArmAsm

/*-
* Copyright (c) 2014 Andrew Turner
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <machine/asm.h>
__FBSDID("$FreeBSD$");
#include "assym.s"
.text
.macro save_registers el
.if \el == 1
mov x18, sp
sub sp, sp, #128
.endif
sub sp, sp, #(TF_SIZE + 16)
stp x29, x30, [sp, #(TF_SIZE)]
stp x28, x29, [sp, #(TF_X + 28 * 8)]
stp x26, x27, [sp, #(TF_X + 26 * 8)]
stp x24, x25, [sp, #(TF_X + 24 * 8)]
stp x22, x23, [sp, #(TF_X + 22 * 8)]
stp x20, x21, [sp, #(TF_X + 20 * 8)]
stp x18, x19, [sp, #(TF_X + 18 * 8)]
stp x16, x17, [sp, #(TF_X + 16 * 8)]
stp x14, x15, [sp, #(TF_X + 14 * 8)]
stp x12, x13, [sp, #(TF_X + 12 * 8)]
stp x10, x11, [sp, #(TF_X + 10 * 8)]
stp x8, x9, [sp, #(TF_X + 8 * 8)]
stp x6, x7, [sp, #(TF_X + 6 * 8)]
stp x4, x5, [sp, #(TF_X + 4 * 8)]
stp x2, x3, [sp, #(TF_X + 2 * 8)]
stp x0, x1, [sp, #(TF_X + 0 * 8)]
mrs x10, elr_el1
mrs x11, spsr_el1
.if \el == 0
mrs x18, sp_el0
.endif
stp x10, x11, [sp, #(TF_ELR)]
stp x18, lr, [sp, #(TF_SP)]
mrs x18, tpidr_el1
add x29, sp, #(TF_SIZE)
.endm
.macro restore_registers el
.if \el == 1
msr daifset, #2
/*
* Disable interrupts, x18 may change in the interrupt exception
* handler. For EL0 exceptions, do_ast already did this.
*/
.endif
ldp x18, lr, [sp, #(TF_SP)]
ldp x10, x11, [sp, #(TF_ELR)]
.if \el == 0
msr sp_el0, x18
.endif
msr spsr_el1, x11
msr elr_el1, x10
ldp x0, x1, [sp, #(TF_X + 0 * 8)]
ldp x2, x3, [sp, #(TF_X + 2 * 8)]
ldp x4, x5, [sp, #(TF_X + 4 * 8)]
ldp x6, x7, [sp, #(TF_X + 6 * 8)]
ldp x8, x9, [sp, #(TF_X + 8 * 8)]
ldp x10, x11, [sp, #(TF_X + 10 * 8)]
ldp x12, x13, [sp, #(TF_X + 12 * 8)]
ldp x14, x15, [sp, #(TF_X + 14 * 8)]
ldp x16, x17, [sp, #(TF_X + 16 * 8)]
.if \el == 0
/*
* We only restore the callee saved registers when returning to
* userland as they may have been updated by a system call or signal.
*/
ldp x18, x19, [sp, #(TF_X + 18 * 8)]
ldp x20, x21, [sp, #(TF_X + 20 * 8)]
ldp x22, x23, [sp, #(TF_X + 22 * 8)]
ldp x24, x25, [sp, #(TF_X + 24 * 8)]
ldp x26, x27, [sp, #(TF_X + 26 * 8)]
ldp x28, x29, [sp, #(TF_X + 28 * 8)]
.else
ldr x29, [sp, #(TF_X + 29 * 8)]
.endif
.if \el == 0
add sp, sp, #(TF_SIZE + 16)
.else
mov sp, x18
mrs x18, tpidr_el1
.endif
.endm
.macro do_ast
/* Disable interrupts */
mrs x19, daif
1:
msr daifset, #2
/* Read the current thread flags */
ldr x1, [x18, #PC_CURTHREAD] /* Load curthread */
ldr x2, [x1, #TD_FLAGS]
/* Check if we have either bits set */
mov x3, #((TDF_ASTPENDING|TDF_NEEDRESCHED) >> 8)
lsl x3, x3, #8
and x2, x2, x3
cbz x2, 2f
/* Restore interrupts */
msr daif, x19
/* handle the ast */
mov x0, sp
bl _C_LABEL(ast)
/* Re-check for new ast scheduled */
b 1b
2:
.endm
ENTRY(handle_el1h_sync)
save_registers 1
mov x0, sp
bl do_el1h_sync
restore_registers 1
eret
END(handle_el1h_sync)
ENTRY(handle_el1h_irq)
save_registers 1
mov x0, sp
bl arm_cpu_intr
restore_registers 1
eret
END(handle_el1h_irq)
ENTRY(handle_el1h_error)
brk 0xf13
END(handle_el1h_error)
ENTRY(handle_el0_sync)
save_registers 0
mov x0, sp
bl do_el0_sync
do_ast
restore_registers 0
eret
END(handle_el0_sync)
ENTRY(handle_el0_irq)
save_registers 0
mov x0, sp
bl arm_cpu_intr
do_ast
restore_registers 0
eret
END(handle_el0_irq)
ENTRY(handle_el0_error)
save_registers 0
mov x0, sp
bl do_el0_error
brk 0xf23
1: b 1b
END(handle_el0_error)
.macro vempty
.align 7
brk 0xfff
1: b 1b
.endm
.macro vector name
.align 7
b handle_\name
.endm
.align 11
.globl exception_vectors
exception_vectors:
vempty /* Synchronous EL1t */
vempty /* IRQ EL1t */
vempty /* FIQ EL1t */
vempty /* Error EL1t */
vector el1h_sync /* Synchronous EL1h */
vector el1h_irq /* IRQ EL1h */
vempty /* FIQ EL1h */
vector el1h_error /* Error EL1h */
vector el0_sync /* Synchronous 64-bit EL0 */
vector el0_irq /* IRQ 64-bit EL0 */
vempty /* FIQ 64-bit EL0 */
vector el0_error /* Error 64-bit EL0 */
vempty /* Synchronous 32-bit EL0 */
vempty /* IRQ 32-bit EL0 */
vempty /* FIQ 32-bit EL0 */
vempty /* Error 32-bit EL0 */