entry.S

  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