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
39badsys:
40	movel	#-ENOSYS,%sp@(PT_OFF_D0)
41	jra	ret_from_exception
42
43do_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
581:	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
63ret_from_signal:
64	RESTORE_SWITCH_STACK
65	addql	#4,%sp
66	jra	ret_from_exception
67
68ENTRY(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
91ret_from_exception:
92	btst	#5,%sp@(PT_OFF_SR)	/* check if returning to kernel*/
93	jeq	Luser_return		/* if so, skip resched, signals*/
94
95Lkernel_return:
96	RESTORE_ALL
97
98Luser_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
1071:
108	move	%a2@(TINFO_FLAGS),%d1	/* thread_info->flags */
109	jne	Lwork_to_do
110	RESTORE_ALL
111
112Lwork_to_do:
113	movel	%a2@(TINFO_FLAGS),%d1	/* thread_info->flags */
114	btst	#TIF_NEED_RESCHED,%d1
115	jne	reschedule
116
117Lsignal_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 */
130inthandler1:
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*/
1383:     	addql	#8,%sp			/*  pop parameters off stack*/
139	bra	ret_from_exception
140
141inthandler2:
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*/
1493:     	addql	#8,%sp			/*  pop parameters off stack*/
150	bra	ret_from_exception
151
152inthandler3:
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*/
1603:     	addql	#8,%sp			/*  pop parameters off stack*/
161	bra	ret_from_exception
162
163inthandler4:
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*/
1713:     	addql	#8,%sp			/*  pop parameters off stack*/
172	bra	ret_from_exception
173
174inthandler5:
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*/
1823:     	addql	#8,%sp			/*  pop parameters off stack*/
183	bra	ret_from_exception
184
185inthandler6:
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*/
1933:     	addql	#8,%sp			/*  pop parameters off stack*/
194	bra	ret_from_exception
195
196inthandler7:
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*/
2043:     	addql	#8,%sp			/*  pop parameters off stack*/
205	bra	ret_from_exception
206
207inthandler:
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*/
2153:     	addql	#8,%sp			/*  pop parameters off stack*/
216	bra	ret_from_exception
217
218/*
219 * Handler for uninitialized and spurious interrupts.
220 */
221ENTRY(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 */
230ENTRY(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
245