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/traps.h>
19#include <asm/asm-offsets.h>
20#include <asm/entry.h>
21
22.text
23
24.globl system_call
25.globl resume
26.globl ret_from_exception
27.globl sys_call_table
28.globl bad_interrupt
29.globl inthandler1
30.globl inthandler2
31.globl inthandler3
32.globl inthandler4
33.globl inthandler5
34.globl inthandler6
35.globl inthandler7
36
37badsys:
38	movel	#-ENOSYS,%sp@(PT_OFF_D0)
39	jra	ret_from_exception
40
41do_trace:
42	movel	#-ENOSYS,%sp@(PT_OFF_D0) /* needed for strace*/
43	subql	#4,%sp
44	SAVE_SWITCH_STACK
45	jbsr	syscall_trace_enter
46	RESTORE_SWITCH_STACK
47	addql	#4,%sp
48	movel	%sp@(PT_OFF_ORIG_D0),%d1
49	movel	#-ENOSYS,%d0
50	cmpl	#NR_syscalls,%d1
51	jcc	1f
52	lsl	#2,%d1
53	lea	sys_call_table, %a0
54	jbsr	%a0@(%d1)
55
561:	movel	%d0,%sp@(PT_OFF_D0)	/* save the return value */
57	subql	#4,%sp			/* dummy return address */
58	SAVE_SWITCH_STACK
59	jbsr	syscall_trace_leave
60	RESTORE_SWITCH_STACK
61	addql	#4,%sp
62	jra	ret_from_exception
63
64ENTRY(system_call)
65	SAVE_ALL_SYS
66
67	/* save top of frame*/
68	pea	%sp@
69	jbsr	set_esp0
70	addql	#4,%sp
71
72	movel	%sp@(PT_OFF_ORIG_D0),%d0
73
74	movel	%sp,%d1			/* get thread_info pointer */
75	andl	#-THREAD_SIZE,%d1
76	movel	%d1,%a2
77	btst	#(TIF_SYSCALL_TRACE%8),%a2@(TINFO_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
78	jne	do_trace
79	cmpl	#NR_syscalls,%d0
80	jcc	badsys
81	lsl	#2,%d0
82	lea	sys_call_table,%a0
83	movel	%a0@(%d0), %a0
84	jbsr	%a0@
85	movel	%d0,%sp@(PT_OFF_D0)	/* save the return value*/
86
87ret_from_exception:
88	btst	#5,%sp@(PT_OFF_SR)	/* check if returning to kernel*/
89	jeq	Luser_return		/* if so, skip resched, signals*/
90
91Lkernel_return:
92	RESTORE_ALL
93
94Luser_return:
95	/* only allow interrupts when we are really the last one on the*/
96	/* kernel stack, otherwise stack overflow can occur during*/
97	/* heavy interrupt load*/
98	andw	#ALLOWINT,%sr
99
100	movel	%sp,%d1			/* get thread_info pointer */
101	andl	#-THREAD_SIZE,%d1
102	movel	%d1,%a2
1031:
104	move	%a2@(TINFO_FLAGS),%d1	/* thread_info->flags */
105	jne	Lwork_to_do
106	RESTORE_ALL
107
108Lwork_to_do:
109	movel	%a2@(TINFO_FLAGS),%d1	/* thread_info->flags */
110	btst	#TIF_NEED_RESCHED,%d1
111	jne	reschedule
112
113Lsignal_return:
114	subql	#4,%sp			/* dummy return address*/
115	SAVE_SWITCH_STACK
116	pea	%sp@(SWITCH_STACK_SIZE)
117	bsrw	do_notify_resume
118	addql	#4,%sp
119	RESTORE_SWITCH_STACK
120	addql	#4,%sp
121	jra	1b
122
123/*
124 * This is the main interrupt handler, responsible for calling process_int()
125 */
126inthandler1:
127	SAVE_ALL_INT
128	movew	%sp@(PT_OFF_FORMATVEC), %d0
129	and	#0x3ff, %d0
130
131	movel	%sp,%sp@-
132	movel	#65,%sp@- 		/*  put vector # on stack*/
133	jbsr	process_int		/*  process the IRQ*/
1343:     	addql	#8,%sp			/*  pop parameters off stack*/
135	bra	ret_from_exception
136
137inthandler2:
138	SAVE_ALL_INT
139	movew	%sp@(PT_OFF_FORMATVEC), %d0
140	and	#0x3ff, %d0
141
142	movel	%sp,%sp@-
143	movel	#66,%sp@- 		/*  put vector # on stack*/
144	jbsr	process_int		/*  process the IRQ*/
1453:     	addql	#8,%sp			/*  pop parameters off stack*/
146	bra	ret_from_exception
147
148inthandler3:
149	SAVE_ALL_INT
150	movew	%sp@(PT_OFF_FORMATVEC), %d0
151	and	#0x3ff, %d0
152
153	movel	%sp,%sp@-
154	movel	#67,%sp@- 		/*  put vector # on stack*/
155	jbsr	process_int		/*  process the IRQ*/
1563:     	addql	#8,%sp			/*  pop parameters off stack*/
157	bra	ret_from_exception
158
159inthandler4:
160	SAVE_ALL_INT
161	movew	%sp@(PT_OFF_FORMATVEC), %d0
162	and	#0x3ff, %d0
163
164	movel	%sp,%sp@-
165	movel	#68,%sp@- 		/*  put vector # on stack*/
166	jbsr	process_int		/*  process the IRQ*/
1673:     	addql	#8,%sp			/*  pop parameters off stack*/
168	bra	ret_from_exception
169
170inthandler5:
171	SAVE_ALL_INT
172	movew	%sp@(PT_OFF_FORMATVEC), %d0
173	and	#0x3ff, %d0
174
175	movel	%sp,%sp@-
176	movel	#69,%sp@- 		/*  put vector # on stack*/
177	jbsr	process_int		/*  process the IRQ*/
1783:     	addql	#8,%sp			/*  pop parameters off stack*/
179	bra	ret_from_exception
180
181inthandler6:
182	SAVE_ALL_INT
183	movew	%sp@(PT_OFF_FORMATVEC), %d0
184	and	#0x3ff, %d0
185
186	movel	%sp,%sp@-
187	movel	#70,%sp@- 		/*  put vector # on stack*/
188	jbsr	process_int		/*  process the IRQ*/
1893:     	addql	#8,%sp			/*  pop parameters off stack*/
190	bra	ret_from_exception
191
192inthandler7:
193	SAVE_ALL_INT
194	movew	%sp@(PT_OFF_FORMATVEC), %d0
195	and	#0x3ff, %d0
196
197	movel	%sp,%sp@-
198	movel	#71,%sp@- 		/*  put vector # on stack*/
199	jbsr	process_int		/*  process the IRQ*/
2003:     	addql	#8,%sp			/*  pop parameters off stack*/
201	bra	ret_from_exception
202
203inthandler:
204	SAVE_ALL_INT
205	movew	%sp@(PT_OFF_FORMATVEC), %d0
206	and	#0x3ff, %d0
207
208	movel	%sp,%sp@-
209	movel	%d0,%sp@- 		/*  put vector # on stack*/
210	jbsr	process_int		/*  process the IRQ*/
2113:     	addql	#8,%sp			/*  pop parameters off stack*/
212	bra	ret_from_exception
213
214/*
215 * Handler for uninitialized and spurious interrupts.
216 */
217ENTRY(bad_interrupt)
218	addql	#1,irq_err_count
219	rte
220
221/*
222 * Beware - when entering resume, prev (the current task) is
223 * in a0, next (the new task) is in a1, so don't change these
224 * registers until their contents are no longer needed.
225 */
226ENTRY(resume)
227	movel	%a0,%d1				/* save prev thread in d1 */
228	movew	%sr,%a0@(TASK_THREAD+THREAD_SR)	/* save sr */
229	SAVE_SWITCH_STACK
230	movel	%sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack */
231	movel	%usp,%a3			/* save usp */
232	movel	%a3,%a0@(TASK_THREAD+THREAD_USP)
233
234	movel	%a1@(TASK_THREAD+THREAD_USP),%a3 /* restore user stack */
235	movel	%a3,%usp
236	movel	%a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
237	RESTORE_SWITCH_STACK
238	movew	%a1@(TASK_THREAD+THREAD_SR),%sr	/* restore thread status reg */
239	rts
240
241