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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* linux/arch/arm/kernel/entry-v7m.S
*
* Copyright (C) 2008 ARM Ltd.
*
* Low-level vector interface routines for the ARMv7-M architecture
*/
#include <asm/page.h>
#include <asm/glue.h>
#include <asm/thread_notify.h>
#include <asm/v7m.h>
#include "entry-header.S"
#ifdef CONFIG_TRACE_IRQFLAGS
#error "CONFIG_TRACE_IRQFLAGS not supported on the current ARMv7M implementation"
#endif
__invalid_entry:
v7m_exception_entry
#ifdef CONFIG_PRINTK
adr r0, strerr
mrs r1, ipsr
mov r2, lr
bl _printk
#endif
mov r0, sp
bl show_regs
1: b 1b
ENDPROC(__invalid_entry)
strerr: .asciz "\nUnhandled exception: IPSR = %08lx LR = %08lx\n"
.align 2
__irq_entry:
v7m_exception_entry
@
@ Invoke the IRQ handler
@
mov r0, sp
ldr_this_cpu sp, irq_stack_ptr, r1, r2
@
@ If we took the interrupt while running in the kernel, we may already
@ be using the IRQ stack, so revert to the original value in that case.
@
subs r2, sp, r0 @ SP above bottom of IRQ stack?
rsbscs r2, r2, #THREAD_SIZE @ ... and below the top?
movcs sp, r0
push {r0, lr} @ preserve LR and original SP
@ routine called with r0 = struct pt_regs *
bl generic_handle_arch_irq
pop {r0, lr}
mov sp, r0
@
@ Check for any pending work if returning to user
@
ldr r1, =BASEADDR_V7M_SCB
ldr r0, [r1, V7M_SCB_ICSR]
tst r0, V7M_SCB_ICSR_RETTOBASE
beq 2f
get_thread_info tsk
ldr r2, [tsk, #TI_FLAGS]
movs r2, r2, lsl #16
beq 2f @ no work pending
mov r0, #V7M_SCB_ICSR_PENDSVSET
str r0, [r1, V7M_SCB_ICSR] @ raise PendSV
2:
@ registers r0-r3 and r12 are automatically restored on exception
@ return. r4-r7 were not clobbered in v7m_exception_entry so for
@ correctness they don't need to be restored. So only r8-r11 must be
@ restored here. The easiest way to do so is to restore r0-r7, too.
ldmia sp!, {r0-r11}
add sp, #PT_REGS_SIZE-S_IP
cpsie i
bx lr
ENDPROC(__irq_entry)
__pendsv_entry:
v7m_exception_entry
ldr r1, =BASEADDR_V7M_SCB
mov r0, #V7M_SCB_ICSR_PENDSVCLR
str r0, [r1, V7M_SCB_ICSR] @ clear PendSV
@ execute the pending work, including reschedule
get_thread_info tsk
mov why, #0
b ret_to_user_from_irq
ENDPROC(__pendsv_entry)
/*
* Register switch for ARMv7-M processors.
* r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
* previous and next are guaranteed not to be the same.
*/
ENTRY(__switch_to)
.fnstart
.cantunwind
add ip, r1, #TI_CPU_SAVE
stmia ip!, {r4 - r11} @ Store most regs on stack
str sp, [ip], #4
str lr, [ip], #4
mov r5, r0
mov r6, r2 @ Preserve 'next'
add r4, r2, #TI_CPU_SAVE
ldr r0, =thread_notify_head
mov r1, #THREAD_NOTIFY_SWITCH
bl atomic_notifier_call_chain
mov r0, r5
mov r1, r6
ldmia r4, {r4 - r12, lr} @ Load all regs saved previously
set_current r1, r2
mov sp, ip
bx lr
.fnend
ENDPROC(__switch_to)
.data
#if CONFIG_CPU_V7M_NUM_IRQ <= 112
.align 9
#else
.align 10
#endif
/*
* Vector table (Natural alignment need to be ensured)
*/
ENTRY(vector_table)
.long 0 @ 0 - Reset stack pointer
.long __invalid_entry @ 1 - Reset
.long __invalid_entry @ 2 - NMI
.long __invalid_entry @ 3 - HardFault
.long __invalid_entry @ 4 - MemManage
.long __invalid_entry @ 5 - BusFault
.long __invalid_entry @ 6 - UsageFault
.long __invalid_entry @ 7 - Reserved
.long __invalid_entry @ 8 - Reserved
.long __invalid_entry @ 9 - Reserved
.long __invalid_entry @ 10 - Reserved
.long vector_swi @ 11 - SVCall
.long __invalid_entry @ 12 - Debug Monitor
.long __invalid_entry @ 13 - Reserved
.long __pendsv_entry @ 14 - PendSV
.long __invalid_entry @ 15 - SysTick
.rept CONFIG_CPU_V7M_NUM_IRQ
.long __irq_entry @ External Interrupts
.endr
.align 2
.globl exc_ret
exc_ret:
.space 4
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