aboutsummaryrefslogtreecommitdiff
path: root/arch/m68knommu/platform/68360/entry.S
blob: 8ff48adf24abec4dbec33f1e8c395ff96ceaed1b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
/*
 *  linux/arch/m68knommu/platform/68360/entry.S
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2001 SED Systems, a Division of Calian Ltd.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file README.legal in the main directory of this archive
 * for more details.
 *
 * Linux/m68k support by Hamish Macdonald
 * M68360 Port by SED Systems, and Lineo.
 */

#include <linux/config.h>
#include <linux/sys.h>
#include <linux/linkage.h>
#include <asm/thread_info.h>
#include <asm/unistd.h>
#include <asm/errno.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/traps.h>
#include <asm/asm-offsets.h>
#include <asm/entry.h>

.text

.globl system_call
.globl resume
.globl ret_from_exception
.globl ret_from_signal
.globl sys_call_table
.globl ret_from_interrupt
.globl bad_interrupt
.globl inthandler

badsys:
	movel	#-ENOSYS,%sp@(PT_D0)
	jra	ret_from_exception

do_trace:
	movel	#-ENOSYS,%sp@(PT_D0)	/* needed for strace*/
	subql	#4,%sp
	SAVE_SWITCH_STACK
	jbsr	syscall_trace
	RESTORE_SWITCH_STACK
	addql	#4,%sp
	movel	%sp@(PT_ORIG_D0),%d1
	movel	#-ENOSYS,%d0
	cmpl	#NR_syscalls,%d1
	jcc	1f
	lsl	#2,%d1
	lea	sys_call_table, %a0
	jbsr	%a0@(%d1)

1:	movel	%d0,%sp@(PT_D0)		/* save the return value */
	subql	#4,%sp			/* dummy return address */
	SAVE_SWITCH_STACK
	jbsr	syscall_trace

ret_from_signal:
	RESTORE_SWITCH_STACK
	addql	#4,%sp
	jra	ret_from_exception

ENTRY(system_call)
	SAVE_ALL

	/* save top of frame*/
	pea	%sp@
	jbsr	set_esp0
	addql	#4,%sp

	btst	#PF_TRACESYS_BIT,%a2@(TASK_FLAGS+PF_TRACESYS_OFF)
	jne	do_trace
	cmpl	#NR_syscalls,%d0
	jcc	badsys
	lsl	#2,%d0
	lea	sys_call_table,%a0
	movel	%a0@(%d0), %a0
	jbsr	%a0@
	movel	%d0,%sp@(PT_D0)		/* save the return value*/

ret_from_exception:
	btst	#5,%sp@(PT_SR)		/* check if returning to kernel*/
	jeq	Luser_return		/* if so, skip resched, signals*/

Lkernel_return:
	RESTORE_ALL

Luser_return:
	/* only allow interrupts when we are really the last one on the*/
	/* kernel stack, otherwise stack overflow can occur during*/
	/* heavy interrupt load*/
	andw	#ALLOWINT,%sr

	movel	%sp,%d1			/* get thread_info pointer */
	andl	#-THREAD_SIZE,%d1
	movel	%d1,%a2
	move	%a2@(TI_FLAGS),%d1	/* thread_info->flags */
	andl	#_TIF_WORK_MASK,%d1
	jne	Lwork_to_do
	RESTORE_ALL

Lwork_to_do:
	movel	%a2@(TI_FLAGS),%d1	/* thread_info->flags */
	btst	#TIF_NEED_RESCHED,%d1
	jne	reschedule

Lsignal_return:
	subql	#4,%sp			/* dummy return address*/
	SAVE_SWITCH_STACK
	pea	%sp@(SWITCH_STACK_SIZE)
	clrl	%sp@-
	bsrw	do_signal
	addql	#8,%sp
	RESTORE_SWITCH_STACK
	addql	#4,%sp
Lreturn:
	RESTORE_ALL

/*
 * This is the main interrupt handler, responsible for calling process_int()
 */
inthandler:
	SAVE_ALL
	addql	#1,local_irq_count	/*  put exception # in d0*/
	movew	%sp@(PT_VECTOR), %d0
	and.l	#0x3ff, %d0
	lsr.l   #0x02,  %d0

	movel	%sp,%sp@-
	movel	%d0,%sp@- 		/*  put vector # on stack*/
	jbsr	process_int		/*  process the IRQ*/
3:     	addql	#8,%sp			/*  pop parameters off stack*/
	bra	ret_from_interrupt

ret_from_interrupt:
	subql	#1,local_irq_count
	jeq	1f
2:
	RESTORE_ALL
1:
	moveb	%sp@(PT_SR), %d0
	and	#7, %d0
	jhi	2b
	/* check if we need to do software interrupts */

	movel	irq_stat+CPUSTAT_SOFTIRQ_PENDING,%d0
	jeq	ret_from_exception

	pea	ret_from_exception
	jra	do_softirq


/*
 * Handler for uninitialized and spurious interrupts.
 */
bad_interrupt:
	addql	#1,num_spurious
	rte

/*
 * Beware - when entering resume, prev (the current task) is
 * in a0, next (the new task) is in a1,so don't change these
 * registers until their contents are no longer needed.
 */
ENTRY(resume)
	movel	%a0,%d1				/* save prev thread in d1 */
	movew	%sr,%a0@(TASK_THREAD+THREAD_SR)	/* save sr */
	movel	%usp,%a2			/* save usp */
	movel	%a2,%a0@(TASK_THREAD+THREAD_USP)

	SAVE_SWITCH_STACK
	movel	%sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack */
	movel	%a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
	RESTORE_SWITCH_STACK

	movel	%a1@(TASK_THREAD+THREAD_USP),%a0 /* restore user stack */
	movel	%a0,%usp
	movew	%a1@(TASK_THREAD+THREAD_SR),%sr	/* restore thread status reg */
	rts