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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * linux/arch/arm/kernel/entry-v7m.S
4 *
5 * Copyright (C) 2008 ARM Ltd.
6 *
7 * Low-level vector interface routines for the ARMv7-M architecture
8 */
9#include <asm/memory.h>
10#include <asm/glue.h>
11#include <asm/thread_notify.h>
12#include <asm/v7m.h>
13
14#include "entry-header.S"
15
16#ifdef CONFIG_TRACE_IRQFLAGS
17#error "CONFIG_TRACE_IRQFLAGS not supported on the current ARMv7M implementation"
18#endif
19
20__invalid_entry:
21 v7m_exception_entry
22#ifdef CONFIG_PRINTK
23 adr r0, strerr
24 mrs r1, ipsr
25 mov r2, lr
26 bl printk
27#endif
28 mov r0, sp
29 bl show_regs
301: b 1b
31ENDPROC(__invalid_entry)
32
33strerr: .asciz "\nUnhandled exception: IPSR = %08lx LR = %08lx\n"
34
35 .align 2
36__irq_entry:
37 v7m_exception_entry
38
39 @
40 @ Invoke the IRQ handler
41 @
42 mrs r0, ipsr
43 ldr r1, =V7M_xPSR_EXCEPTIONNO
44 and r0, r1
45 sub r0, #16
46 mov r1, sp
47 stmdb sp!, {lr}
48 @ routine called with r0 = irq number, r1 = struct pt_regs *
49 bl nvic_handle_irq
50
51 pop {lr}
52 @
53 @ Check for any pending work if returning to user
54 @
55 ldr r1, =BASEADDR_V7M_SCB
56 ldr r0, [r1, V7M_SCB_ICSR]
57 tst r0, V7M_SCB_ICSR_RETTOBASE
58 beq 2f
59
60 get_thread_info tsk
61 ldr r2, [tsk, #TI_FLAGS]
62 tst r2, #_TIF_WORK_MASK
63 beq 2f @ no work pending
64 mov r0, #V7M_SCB_ICSR_PENDSVSET
65 str r0, [r1, V7M_SCB_ICSR] @ raise PendSV
66
672:
68 @ registers r0-r3 and r12 are automatically restored on exception
69 @ return. r4-r7 were not clobbered in v7m_exception_entry so for
70 @ correctness they don't need to be restored. So only r8-r11 must be
71 @ restored here. The easiest way to do so is to restore r0-r7, too.
72 ldmia sp!, {r0-r11}
73 add sp, #PT_REGS_SIZE-S_IP
74 cpsie i
75 bx lr
76ENDPROC(__irq_entry)
77
78__pendsv_entry:
79 v7m_exception_entry
80
81 ldr r1, =BASEADDR_V7M_SCB
82 mov r0, #V7M_SCB_ICSR_PENDSVCLR
83 str r0, [r1, V7M_SCB_ICSR] @ clear PendSV
84
85 @ execute the pending work, including reschedule
86 get_thread_info tsk
87 mov why, #0
88 b ret_to_user_from_irq
89ENDPROC(__pendsv_entry)
90
91/*
92 * Register switch for ARMv7-M processors.
93 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
94 * previous and next are guaranteed not to be the same.
95 */
96ENTRY(__switch_to)
97 .fnstart
98 .cantunwind
99 add ip, r1, #TI_CPU_SAVE
100 stmia ip!, {r4 - r11} @ Store most regs on stack
101 str sp, [ip], #4
102 str lr, [ip], #4
103 mov r5, r0
104 add r4, r2, #TI_CPU_SAVE
105 ldr r0, =thread_notify_head
106 mov r1, #THREAD_NOTIFY_SWITCH
107 bl atomic_notifier_call_chain
108 mov ip, r4
109 mov r0, r5
110 ldmia ip!, {r4 - r11} @ Load all regs saved previously
111 ldr sp, [ip]
112 ldr pc, [ip, #4]!
113 .fnend
114ENDPROC(__switch_to)
115
116 .data
117#if CONFIG_CPU_V7M_NUM_IRQ <= 112
118 .align 9
119#else
120 .align 10
121#endif
122
123/*
124 * Vector table (Natural alignment need to be ensured)
125 */
126ENTRY(vector_table)
127 .long 0 @ 0 - Reset stack pointer
128 .long __invalid_entry @ 1 - Reset
129 .long __invalid_entry @ 2 - NMI
130 .long __invalid_entry @ 3 - HardFault
131 .long __invalid_entry @ 4 - MemManage
132 .long __invalid_entry @ 5 - BusFault
133 .long __invalid_entry @ 6 - UsageFault
134 .long __invalid_entry @ 7 - Reserved
135 .long __invalid_entry @ 8 - Reserved
136 .long __invalid_entry @ 9 - Reserved
137 .long __invalid_entry @ 10 - Reserved
138 .long vector_swi @ 11 - SVCall
139 .long __invalid_entry @ 12 - Debug Monitor
140 .long __invalid_entry @ 13 - Reserved
141 .long __pendsv_entry @ 14 - PendSV
142 .long __invalid_entry @ 15 - SysTick
143 .rept CONFIG_CPU_V7M_NUM_IRQ
144 .long __irq_entry @ External Interrupts
145 .endr
146 .align 2
147 .globl exc_ret
148exc_ret:
149 .space 4
1/*
2 * linux/arch/arm/kernel/entry-v7m.S
3 *
4 * Copyright (C) 2008 ARM Ltd.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Low-level vector interface routines for the ARMv7-M architecture
11 */
12#include <asm/memory.h>
13#include <asm/glue.h>
14#include <asm/thread_notify.h>
15#include <asm/v7m.h>
16
17#include "entry-header.S"
18
19#ifdef CONFIG_TRACE_IRQFLAGS
20#error "CONFIG_TRACE_IRQFLAGS not supported on the current ARMv7M implementation"
21#endif
22
23__invalid_entry:
24 v7m_exception_entry
25#ifdef CONFIG_PRINTK
26 adr r0, strerr
27 mrs r1, ipsr
28 mov r2, lr
29 bl printk
30#endif
31 mov r0, sp
32 bl show_regs
331: b 1b
34ENDPROC(__invalid_entry)
35
36strerr: .asciz "\nUnhandled exception: IPSR = %08lx LR = %08lx\n"
37
38 .align 2
39__irq_entry:
40 v7m_exception_entry
41
42 @
43 @ Invoke the IRQ handler
44 @
45 mrs r0, ipsr
46 ldr r1, =V7M_xPSR_EXCEPTIONNO
47 and r0, r1
48 sub r0, #16
49 mov r1, sp
50 stmdb sp!, {lr}
51 @ routine called with r0 = irq number, r1 = struct pt_regs *
52 bl nvic_handle_irq
53
54 pop {lr}
55 @
56 @ Check for any pending work if returning to user
57 @
58 ldr r1, =BASEADDR_V7M_SCB
59 ldr r0, [r1, V7M_SCB_ICSR]
60 tst r0, V7M_SCB_ICSR_RETTOBASE
61 beq 2f
62
63 get_thread_info tsk
64 ldr r2, [tsk, #TI_FLAGS]
65 tst r2, #_TIF_WORK_MASK
66 beq 2f @ no work pending
67 mov r0, #V7M_SCB_ICSR_PENDSVSET
68 str r0, [r1, V7M_SCB_ICSR] @ raise PendSV
69
702:
71 @ registers r0-r3 and r12 are automatically restored on exception
72 @ return. r4-r7 were not clobbered in v7m_exception_entry so for
73 @ correctness they don't need to be restored. So only r8-r11 must be
74 @ restored here. The easiest way to do so is to restore r0-r7, too.
75 ldmia sp!, {r0-r11}
76 add sp, #PT_REGS_SIZE-S_IP
77 cpsie i
78 bx lr
79ENDPROC(__irq_entry)
80
81__pendsv_entry:
82 v7m_exception_entry
83
84 ldr r1, =BASEADDR_V7M_SCB
85 mov r0, #V7M_SCB_ICSR_PENDSVCLR
86 str r0, [r1, V7M_SCB_ICSR] @ clear PendSV
87
88 @ execute the pending work, including reschedule
89 get_thread_info tsk
90 mov why, #0
91 b ret_to_user_from_irq
92ENDPROC(__pendsv_entry)
93
94/*
95 * Register switch for ARMv7-M processors.
96 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
97 * previous and next are guaranteed not to be the same.
98 */
99ENTRY(__switch_to)
100 .fnstart
101 .cantunwind
102 add ip, r1, #TI_CPU_SAVE
103 stmia ip!, {r4 - r11} @ Store most regs on stack
104 str sp, [ip], #4
105 str lr, [ip], #4
106 mov r5, r0
107 add r4, r2, #TI_CPU_SAVE
108 ldr r0, =thread_notify_head
109 mov r1, #THREAD_NOTIFY_SWITCH
110 bl atomic_notifier_call_chain
111 mov ip, r4
112 mov r0, r5
113 ldmia ip!, {r4 - r11} @ Load all regs saved previously
114 ldr sp, [ip]
115 ldr pc, [ip, #4]!
116 .fnend
117ENDPROC(__switch_to)
118
119 .data
120#if CONFIG_CPU_V7M_NUM_IRQ <= 112
121 .align 9
122#else
123 .align 10
124#endif
125
126/*
127 * Vector table (Natural alignment need to be ensured)
128 */
129ENTRY(vector_table)
130 .long 0 @ 0 - Reset stack pointer
131 .long __invalid_entry @ 1 - Reset
132 .long __invalid_entry @ 2 - NMI
133 .long __invalid_entry @ 3 - HardFault
134 .long __invalid_entry @ 4 - MemManage
135 .long __invalid_entry @ 5 - BusFault
136 .long __invalid_entry @ 6 - UsageFault
137 .long __invalid_entry @ 7 - Reserved
138 .long __invalid_entry @ 8 - Reserved
139 .long __invalid_entry @ 9 - Reserved
140 .long __invalid_entry @ 10 - Reserved
141 .long vector_swi @ 11 - SVCall
142 .long __invalid_entry @ 12 - Debug Monitor
143 .long __invalid_entry @ 13 - Reserved
144 .long __pendsv_entry @ 14 - PendSV
145 .long __invalid_entry @ 15 - SysTick
146 .rept CONFIG_CPU_V7M_NUM_IRQ
147 .long __irq_entry @ External Interrupts
148 .endr