1/*
2 *  entry.S  -- interrupt and exception processing for ColdFire
3 *
4 *  Copyright (C) 1999-2007, Greg Ungerer (gerg@snapgear.com)
5 *  Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
6 *                      Kenneth Albanowski <kjahds@kjahds.com>,
7 *  Copyright (C) 2000  Lineo Inc. (www.lineo.com)
8 *  Copyright (C) 2004-2006  Macq Electronique SA. (www.macqel.com)
9 *
10 * Based on:
11 *
12 *  linux/arch/m68k/kernel/entry.S
13 *
14 *  Copyright (C) 1991, 1992  Linus Torvalds
15 *
16 * This file is subject to the terms and conditions of the GNU General Public
17 * License.  See the file README.legal in the main directory of this archive
18 * for more details.
19 *
20 * Linux/m68k support by Hamish Macdonald
21 *
22 * 68060 fixes by Jesper Skov
23 * ColdFire support by Greg Ungerer (gerg@snapgear.com)
24 * 5307 fixes by David W. Miller
25 * linux 2.4 support David McCullough <davidm@snapgear.com>
26 * Bug, speed and maintainability fixes by Philippe De Muyter <phdm@macqel.be>
27 */
28
29#include <linux/linkage.h>
30#include <asm/unistd.h>
31#include <asm/thread_info.h>
32#include <asm/errno.h>
33#include <asm/setup.h>
34#include <asm/segment.h>
35#include <asm/asm-offsets.h>
36#include <asm/entry.h>
37
38#ifdef CONFIG_COLDFIRE_SW_A7
39/*
40 *	Define software copies of the supervisor and user stack pointers.
41 */
42.bss
43sw_ksp:
44.long	0
45sw_usp:
46.long	0
47#endif /* CONFIG_COLDFIRE_SW_A7 */
48
49.text
50
51.globl system_call
52.globl resume
53.globl ret_from_exception
54.globl ret_from_signal
55.globl sys_call_table
56.globl inthandler
57
58enosys:
59	mov.l	#sys_ni_syscall,%d3
60	bra	1f
61
62ENTRY(system_call)
63	SAVE_ALL_SYS
64	move	#0x2000,%sr		/* enable intrs again */
65	GET_CURRENT(%d2)
66
67	cmpl	#NR_syscalls,%d0
68	jcc	enosys
69	lea	sys_call_table,%a0
70	lsll	#2,%d0			/* movel %a0@(%d0:l:4),%d3 */
71	movel	%a0@(%d0),%d3
72	jeq	enosys
73
741:
75	movel	%sp,%d2			/* get thread_info pointer */
76	andl	#-THREAD_SIZE,%d2	/* at start of kernel stack */
77	movel	%d2,%a0
78	movel	%a0@,%a1		/* save top of frame */
79	movel	%sp,%a1@(TASK_THREAD+THREAD_ESP0)
80	btst	#(TIF_SYSCALL_TRACE%8),%a0@(TINFO_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
81	bnes	1f
82
83	movel	%d3,%a0
84	jbsr	%a0@
85	movel	%d0,%sp@(PT_OFF_D0)	/* save the return value */
86	jra	ret_from_exception
871:
88	movel	#-ENOSYS,%d2		/* strace needs -ENOSYS in PT_OFF_D0 */
89	movel	%d2,PT_OFF_D0(%sp)	/* on syscall entry */
90	subql	#4,%sp
91	SAVE_SWITCH_STACK
92	jbsr	syscall_trace_enter
93	RESTORE_SWITCH_STACK
94	addql	#4,%sp
95	movel	%d3,%a0
96	jbsr	%a0@
97	movel	%d0,%sp@(PT_OFF_D0)		/* save the return value */
98	subql	#4,%sp			/* dummy return address */
99	SAVE_SWITCH_STACK
100	jbsr	syscall_trace_leave
101
102ret_from_signal:
103	RESTORE_SWITCH_STACK
104	addql	#4,%sp
105
106ret_from_exception:
107	move	#0x2700,%sr		/* disable intrs */
108	btst	#5,%sp@(PT_OFF_SR)	/* check if returning to kernel */
109	jeq	Luser_return		/* if so, skip resched, signals */
110
111#ifdef CONFIG_PREEMPT
112	movel	%sp,%d1			/* get thread_info pointer */
113	andl	#-THREAD_SIZE,%d1	/* at base of kernel stack */
114	movel	%d1,%a0
115	movel	%a0@(TINFO_FLAGS),%d1	/* get thread_info->flags */
116	andl	#(1<<TIF_NEED_RESCHED),%d1
117	jeq	Lkernel_return
118
119	movel	%a0@(TINFO_PREEMPT),%d1
120	cmpl	#0,%d1
121	jne	Lkernel_return
122
123	pea	Lkernel_return
124	jmp	preempt_schedule_irq	/* preempt the kernel */
125#endif
126
127Lkernel_return:
128	moveml	%sp@,%d1-%d5/%a0-%a2
129	lea	%sp@(32),%sp		/* space for 8 regs */
130	movel	%sp@+,%d0
131	addql	#4,%sp			/* orig d0 */
132	addl	%sp@+,%sp		/* stk adj */
133	rte
134
135Luser_return:
136	movel	%sp,%d1			/* get thread_info pointer */
137	andl	#-THREAD_SIZE,%d1	/* at base of kernel stack */
138	movel	%d1,%a0
139	moveb	%a0@(TINFO_FLAGS+3),%d1	/* thread_info->flags (low 8 bits) */
140	jne	Lwork_to_do		/* still work to do */
141
142Lreturn:
143	RESTORE_USER
144
145Lwork_to_do:
146	movel	%a0@(TINFO_FLAGS),%d1	/* get thread_info->flags */
147	move	#0x2000,%sr		/* enable intrs again */
148	btst	#TIF_NEED_RESCHED,%d1
149	jne	reschedule
150
151Lsignal_return:
152	subql	#4,%sp			/* dummy return address */
153	SAVE_SWITCH_STACK
154	pea	%sp@(SWITCH_STACK_SIZE)
155	jsr	do_notify_resume
156	addql	#4,%sp
157	RESTORE_SWITCH_STACK
158	addql	#4,%sp
159	jmp	Luser_return
160
161/*
162 * This is the generic interrupt handler (for all hardware interrupt
163 * sources). Calls up to high level code to do all the work.
164 */
165ENTRY(inthandler)
166	SAVE_ALL_INT
167	GET_CURRENT(%d2)
168
169	movew	%sp@(PT_OFF_FORMATVEC),%d0 /* put exception # in d0 */
170	andl	#0x03fc,%d0		/* mask out vector only */
171
172	movel	%sp,%sp@-		/* push regs arg */
173	lsrl	#2,%d0			/* calculate real vector # */
174	movel	%d0,%sp@-		/* push vector number */
175	jbsr	do_IRQ			/* call high level irq handler */
176	lea	%sp@(8),%sp		/* pop args off stack */
177
178	bra	ret_from_exception
179
180/*
181 * Beware - when entering resume, prev (the current task) is
182 * in a0, next (the new task) is in a1, so don't change these
183 * registers until their contents are no longer needed.
184 */
185ENTRY(resume)
186	movew	%sr,%d1				 /* save current status */
187	movew	%d1,%a0@(TASK_THREAD+THREAD_SR)
188	movel	%a0,%d1				 /* get prev thread in d1 */
189	SAVE_SWITCH_STACK
190	movel	%sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack pointer */
191	RDUSP					 /* movel %usp,%a3 */
192	movel	%a3,%a0@(TASK_THREAD+THREAD_USP) /* save thread user stack */
193#ifdef CONFIG_MMU
194	movel	%a1,%a2				 /* set new current */
195#endif
196	movel	%a1@(TASK_THREAD+THREAD_USP),%a3 /* restore thread user stack */
197	WRUSP					 /* movel %a3,%usp */
198	movel	%a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new kernel stack */
199	movew	%a1@(TASK_THREAD+THREAD_SR),%d7	 /* restore new status */
200	movew	%d7,%sr
201	RESTORE_SWITCH_STACK
202	rts
203
204