summaryrefslogtreecommitdiffstats
path: root/arch/arm/kernel/entry-v7m.S
blob: de8a60363c8597769d0d3b5d8bbe28208c724bdd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
/* 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/memory.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