1/* SPDX-License-Identifier: GPL-2.0-or-later
2 *
3 * entry.S -- non-mmu 68000 interrupt and exception entry points
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 *
7 * Linux/m68k support by Hamish Macdonald
8 */
9
10#include <linux/linkage.h>
11#include <asm/thread_info.h>
12#include <asm/unistd.h>
13#include <asm/errno.h>
14#include <asm/setup.h>
15#include <asm/traps.h>
16#include <asm/asm-offsets.h>
17#include <asm/entry.h>
18
19.text
20
21.globl system_call
22.globl resume
23.globl ret_from_exception
24.globl sys_call_table
25.globl bad_interrupt
26.globl inthandler1
27.globl inthandler2
28.globl inthandler3
29.globl inthandler4
30.globl inthandler5
31.globl inthandler6
32.globl inthandler7
33
34badsys:
35 movel #-ENOSYS,%sp@(PT_OFF_D0)
36 jra ret_from_exception
37
38do_trace:
39 movel #-ENOSYS,%sp@(PT_OFF_D0) /* needed for strace*/
40 subql #4,%sp
41 SAVE_SWITCH_STACK
42 jbsr syscall_trace_enter
43 RESTORE_SWITCH_STACK
44 addql #4,%sp
45 addql #1,%d0
46 jeq ret_from_exception
47 movel %sp@(PT_OFF_ORIG_D0),%d1
48 movel #-ENOSYS,%d0
49 cmpl #NR_syscalls,%d1
50 jcc 1f
51 lsl #2,%d1
52 lea sys_call_table, %a0
53 jbsr %a0@(%d1)
54
551: movel %d0,%sp@(PT_OFF_D0) /* save the return value */
56 subql #4,%sp /* dummy return address */
57 SAVE_SWITCH_STACK
58 jbsr syscall_trace_leave
59 RESTORE_SWITCH_STACK
60 addql #4,%sp
61 jra ret_from_exception
62
63ENTRY(system_call)
64 SAVE_ALL_SYS
65
66 /* save top of frame*/
67 pea %sp@
68 jbsr set_esp0
69 addql #4,%sp
70
71 movel %sp@(PT_OFF_ORIG_D0),%d0
72
73 movel %sp,%d1 /* get thread_info pointer */
74 andl #-THREAD_SIZE,%d1
75 movel %d1,%a2
76 btst #(TIF_SYSCALL_TRACE%8),%a2@(TINFO_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
77 jne do_trace
78 cmpl #NR_syscalls,%d0
79 jcc badsys
80 lsl #2,%d0
81 lea sys_call_table,%a0
82 movel %a0@(%d0), %a0
83 jbsr %a0@
84 movel %d0,%sp@(PT_OFF_D0) /* save the return value*/
85
86ret_from_exception:
87 btst #5,%sp@(PT_OFF_SR) /* check if returning to kernel*/
88 jeq Luser_return /* if so, skip resched, signals*/
89
90Lkernel_return:
91 RESTORE_ALL
92
93Luser_return:
94 /* only allow interrupts when we are really the last one on the*/
95 /* kernel stack, otherwise stack overflow can occur during*/
96 /* heavy interrupt load*/
97 andw #ALLOWINT,%sr
98
99 movel %sp,%d1 /* get thread_info pointer */
100 andl #-THREAD_SIZE,%d1
101 movel %d1,%a2
1021:
103 move %a2@(TINFO_FLAGS),%d1 /* thread_info->flags */
104 jne Lwork_to_do
105 RESTORE_ALL
106
107Lwork_to_do:
108 movel %a2@(TINFO_FLAGS),%d1 /* thread_info->flags */
109 btst #TIF_NEED_RESCHED,%d1
110 jne reschedule
111
112Lsignal_return:
113 subql #4,%sp /* dummy return address*/
114 SAVE_SWITCH_STACK
115 pea %sp@(SWITCH_STACK_SIZE)
116 bsrw do_notify_resume
117 addql #4,%sp
118 RESTORE_SWITCH_STACK
119 addql #4,%sp
120 jra 1b
121
122/*
123 * This is the main interrupt handler, responsible for calling process_int()
124 */
125inthandler1:
126 SAVE_ALL_INT
127 movew %sp@(PT_OFF_FORMATVEC), %d0
128 and #0x3ff, %d0
129
130 movel %sp,%sp@-
131 movel #65,%sp@- /* put vector # on stack*/
132 jbsr process_int /* process the IRQ*/
1333: addql #8,%sp /* pop parameters off stack*/
134 bra ret_from_exception
135
136inthandler2:
137 SAVE_ALL_INT
138 movew %sp@(PT_OFF_FORMATVEC), %d0
139 and #0x3ff, %d0
140
141 movel %sp,%sp@-
142 movel #66,%sp@- /* put vector # on stack*/
143 jbsr process_int /* process the IRQ*/
1443: addql #8,%sp /* pop parameters off stack*/
145 bra ret_from_exception
146
147inthandler3:
148 SAVE_ALL_INT
149 movew %sp@(PT_OFF_FORMATVEC), %d0
150 and #0x3ff, %d0
151
152 movel %sp,%sp@-
153 movel #67,%sp@- /* put vector # on stack*/
154 jbsr process_int /* process the IRQ*/
1553: addql #8,%sp /* pop parameters off stack*/
156 bra ret_from_exception
157
158inthandler4:
159 SAVE_ALL_INT
160 movew %sp@(PT_OFF_FORMATVEC), %d0
161 and #0x3ff, %d0
162
163 movel %sp,%sp@-
164 movel #68,%sp@- /* put vector # on stack*/
165 jbsr process_int /* process the IRQ*/
1663: addql #8,%sp /* pop parameters off stack*/
167 bra ret_from_exception
168
169inthandler5:
170 SAVE_ALL_INT
171 movew %sp@(PT_OFF_FORMATVEC), %d0
172 and #0x3ff, %d0
173
174 movel %sp,%sp@-
175 movel #69,%sp@- /* put vector # on stack*/
176 jbsr process_int /* process the IRQ*/
1773: addql #8,%sp /* pop parameters off stack*/
178 bra ret_from_exception
179
180inthandler6:
181 SAVE_ALL_INT
182 movew %sp@(PT_OFF_FORMATVEC), %d0
183 and #0x3ff, %d0
184
185 movel %sp,%sp@-
186 movel #70,%sp@- /* put vector # on stack*/
187 jbsr process_int /* process the IRQ*/
1883: addql #8,%sp /* pop parameters off stack*/
189 bra ret_from_exception
190
191inthandler7:
192 SAVE_ALL_INT
193 movew %sp@(PT_OFF_FORMATVEC), %d0
194 and #0x3ff, %d0
195
196 movel %sp,%sp@-
197 movel #71,%sp@- /* put vector # on stack*/
198 jbsr process_int /* process the IRQ*/
1993: addql #8,%sp /* pop parameters off stack*/
200 bra ret_from_exception
201
202inthandler:
203 SAVE_ALL_INT
204 movew %sp@(PT_OFF_FORMATVEC), %d0
205 and #0x3ff, %d0
206
207 movel %sp,%sp@-
208 movel %d0,%sp@- /* put vector # on stack*/
209 jbsr process_int /* process the IRQ*/
2103: addql #8,%sp /* pop parameters off stack*/
211 bra ret_from_exception
212
213/*
214 * Handler for uninitialized and spurious interrupts.
215 */
216ENTRY(bad_interrupt)
217 addql #1,irq_err_count
218 rte
219
220/*
221 * Beware - when entering resume, prev (the current task) is
222 * in a0, next (the new task) is in a1, so don't change these
223 * registers until their contents are no longer needed.
224 */
225ENTRY(resume)
226 movel %a0,%d1 /* save prev thread in d1 */
227 movew %sr,%a0@(TASK_THREAD+THREAD_SR) /* save sr */
228 SAVE_SWITCH_STACK
229 movel %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack */
230 movel %usp,%a3 /* save usp */
231 movel %a3,%a0@(TASK_THREAD+THREAD_USP)
232
233 movel %a1@(TASK_THREAD+THREAD_USP),%a3 /* restore user stack */
234 movel %a3,%usp
235 movel %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
236 RESTORE_SWITCH_STACK
237 movew %a1@(TASK_THREAD+THREAD_SR),%sr /* restore thread status reg */
238 rts
239
240

source code of linux/arch/m68k/68000/entry.S