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1 /*
2 * entry.S -- non-mmu 68000 interrupt and exception entry points
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file README.legal in the main directory of this archive
8 * for more details.
9 *
10 * Linux/m68k support by Hamish Macdonald
11 */
12
13 #include <linux/linkage.h>
14 #include <asm/thread_info.h>
15 #include <asm/unistd.h>
16 #include <asm/errno.h>
17 #include <asm/setup.h>
18 #include <asm/segment.h>
19 #include <asm/traps.h>
20 #include <asm/asm-offsets.h>
21 #include <asm/entry.h>
22
23 .text
24
25 .globl system_call
26 .globl resume
27 .globl ret_from_exception
28 .globl ret_from_signal
29 .globl sys_call_table
30 .globl bad_interrupt
31 .globl inthandler1
32 .globl inthandler2
33 .globl inthandler3
34 .globl inthandler4
35 .globl inthandler5
36 .globl inthandler6
37 .globl inthandler7
38
39 badsys:
40 movel #-ENOSYS,%sp@(PT_OFF_D0)
41 jra ret_from_exception
42
43 do_trace:
44 movel #-ENOSYS,%sp@(PT_OFF_D0) /* needed for strace*/
45 subql #4,%sp
46 SAVE_SWITCH_STACK
47 jbsr syscall_trace_enter
48 RESTORE_SWITCH_STACK
49 addql #4,%sp
50 movel %sp@(PT_OFF_ORIG_D0),%d1
51 movel #-ENOSYS,%d0
52 cmpl #NR_syscalls,%d1
53 jcc 1f
54 lsl #2,%d1
55 lea sys_call_table, %a0
56 jbsr %a0@(%d1)
57
58 1: movel %d0,%sp@(PT_OFF_D0) /* save the return value */
59 subql #4,%sp /* dummy return address */
60 SAVE_SWITCH_STACK
61 jbsr syscall_trace_leave
62
63 ret_from_signal:
64 RESTORE_SWITCH_STACK
65 addql #4,%sp
66 jra ret_from_exception
67
68 ENTRY(system_call)
69 SAVE_ALL_SYS
70
71 /* save top of frame*/
72 pea %sp@
73 jbsr set_esp0
74 addql #4,%sp
75
76 movel %sp@(PT_OFF_ORIG_D0),%d0
77
78 movel %sp,%d1 /* get thread_info pointer */
79 andl #-THREAD_SIZE,%d1
80 movel %d1,%a2
81 btst #(TIF_SYSCALL_TRACE%8),%a2@(TINFO_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
82 jne do_trace
83 cmpl #NR_syscalls,%d0
84 jcc badsys
85 lsl #2,%d0
86 lea sys_call_table,%a0
87 movel %a0@(%d0), %a0
88 jbsr %a0@
89 movel %d0,%sp@(PT_OFF_D0) /* save the return value*/
90
91 ret_from_exception:
92 btst #5,%sp@(PT_OFF_SR) /* check if returning to kernel*/
93 jeq Luser_return /* if so, skip resched, signals*/
94
95 Lkernel_return:
96 RESTORE_ALL
97
98 Luser_return:
99 /* only allow interrupts when we are really the last one on the*/
100 /* kernel stack, otherwise stack overflow can occur during*/
101 /* heavy interrupt load*/
102 andw #ALLOWINT,%sr
103
104 movel %sp,%d1 /* get thread_info pointer */
105 andl #-THREAD_SIZE,%d1
106 movel %d1,%a2
107 1:
108 move %a2@(TINFO_FLAGS),%d1 /* thread_info->flags */
109 jne Lwork_to_do
110 RESTORE_ALL
111
112 Lwork_to_do:
113 movel %a2@(TINFO_FLAGS),%d1 /* thread_info->flags */
114 btst #TIF_NEED_RESCHED,%d1
115 jne reschedule
116
117 Lsignal_return:
118 subql #4,%sp /* dummy return address*/
119 SAVE_SWITCH_STACK
120 pea %sp@(SWITCH_STACK_SIZE)
121 bsrw do_notify_resume
122 addql #4,%sp
123 RESTORE_SWITCH_STACK
124 addql #4,%sp
125 jra 1b
126
127 /*
128 * This is the main interrupt handler, responsible for calling process_int()
129 */
130 inthandler1:
131 SAVE_ALL_INT
132 movew %sp@(PT_OFF_FORMATVEC), %d0
133 and #0x3ff, %d0
134
135 movel %sp,%sp@-
136 movel #65,%sp@- /* put vector # on stack*/
137 jbsr process_int /* process the IRQ*/
138 3: addql #8,%sp /* pop parameters off stack*/
139 bra ret_from_exception
140
141 inthandler2:
142 SAVE_ALL_INT
143 movew %sp@(PT_OFF_FORMATVEC), %d0
144 and #0x3ff, %d0
145
146 movel %sp,%sp@-
147 movel #66,%sp@- /* put vector # on stack*/
148 jbsr process_int /* process the IRQ*/
149 3: addql #8,%sp /* pop parameters off stack*/
150 bra ret_from_exception
151
152 inthandler3:
153 SAVE_ALL_INT
154 movew %sp@(PT_OFF_FORMATVEC), %d0
155 and #0x3ff, %d0
156
157 movel %sp,%sp@-
158 movel #67,%sp@- /* put vector # on stack*/
159 jbsr process_int /* process the IRQ*/
160 3: addql #8,%sp /* pop parameters off stack*/
161 bra ret_from_exception
162
163 inthandler4:
164 SAVE_ALL_INT
165 movew %sp@(PT_OFF_FORMATVEC), %d0
166 and #0x3ff, %d0
167
168 movel %sp,%sp@-
169 movel #68,%sp@- /* put vector # on stack*/
170 jbsr process_int /* process the IRQ*/
171 3: addql #8,%sp /* pop parameters off stack*/
172 bra ret_from_exception
173
174 inthandler5:
175 SAVE_ALL_INT
176 movew %sp@(PT_OFF_FORMATVEC), %d0
177 and #0x3ff, %d0
178
179 movel %sp,%sp@-
180 movel #69,%sp@- /* put vector # on stack*/
181 jbsr process_int /* process the IRQ*/
182 3: addql #8,%sp /* pop parameters off stack*/
183 bra ret_from_exception
184
185 inthandler6:
186 SAVE_ALL_INT
187 movew %sp@(PT_OFF_FORMATVEC), %d0
188 and #0x3ff, %d0
189
190 movel %sp,%sp@-
191 movel #70,%sp@- /* put vector # on stack*/
192 jbsr process_int /* process the IRQ*/
193 3: addql #8,%sp /* pop parameters off stack*/
194 bra ret_from_exception
195
196 inthandler7:
197 SAVE_ALL_INT
198 movew %sp@(PT_OFF_FORMATVEC), %d0
199 and #0x3ff, %d0
200
201 movel %sp,%sp@-
202 movel #71,%sp@- /* put vector # on stack*/
203 jbsr process_int /* process the IRQ*/
204 3: addql #8,%sp /* pop parameters off stack*/
205 bra ret_from_exception
206
207 inthandler:
208 SAVE_ALL_INT
209 movew %sp@(PT_OFF_FORMATVEC), %d0
210 and #0x3ff, %d0
211
212 movel %sp,%sp@-
213 movel %d0,%sp@- /* put vector # on stack*/
214 jbsr process_int /* process the IRQ*/
215 3: addql #8,%sp /* pop parameters off stack*/
216 bra ret_from_exception
217
218 /*
219 * Handler for uninitialized and spurious interrupts.
220 */
221 ENTRY(bad_interrupt)
222 addql #1,irq_err_count
223 rte
224
225 /*
226 * Beware - when entering resume, prev (the current task) is
227 * in a0, next (the new task) is in a1, so don't change these
228 * registers until their contents are no longer needed.
229 */
230 ENTRY(resume)
231 movel %a0,%d1 /* save prev thread in d1 */
232 movew %sr,%a0@(TASK_THREAD+THREAD_SR) /* save sr */
233 SAVE_SWITCH_STACK
234 movel %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack */
235 movel %usp,%a3 /* save usp */
236 movel %a3,%a0@(TASK_THREAD+THREAD_USP)
237
238 movel %a1@(TASK_THREAD+THREAD_USP),%a3 /* restore user stack */
239 movel %a3,%usp
240 movel %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
241 RESTORE_SWITCH_STACK
242 movew %a1@(TASK_THREAD+THREAD_SR),%sr /* restore thread status reg */
243 rts
244