[mirror_ubuntu-bionic-kernel.git] / arch / m68k / kernel / entry_mm.S

/* -*- mode: asm -*-
 *
 *  linux/arch/m68k/kernel/entry.S
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 * 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
 *
 * 68060 fixes by Jesper Skov
 *
 */

/*
 * entry.S  contains the system-call and fault low-level handling routines.
 * This also contains the timer-interrupt handler, as well as all interrupts
 * and faults that can result in a task-switch.
 *
 * NOTE: This code handles signal-recognition, which happens every time
 * after a timer-interrupt and after each system call.
 *
 */

/*
 * 12/03/96 Jes: Currently we only support m68k single-cpu systems, so
 *               all pointers that used to be 'current' are now entry
 *               number 0 in the 'current_set' list.
 *
 *  6/05/00 RZ:	 addedd writeback completion after return from sighandler
 *		 for 68040
 */

#include <linux/linkage.h>
#include <asm/entry.h>
#include <asm/errno.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/traps.h>
#include <asm/unistd.h>

#include <asm/asm-offsets.h>

.globl system_call, buserr, trap, resume
.globl sys_call_table
.globl sys_fork, sys_clone, sys_vfork
.globl ret_from_interrupt, bad_interrupt
.globl auto_irqhandler_fixup
.globl user_irqvec_fixup, user_irqhandler_fixup

.text
ENTRY(buserr)
	SAVE_ALL_INT
	GET_CURRENT(%d0)
	movel	%sp,%sp@-		| stack frame pointer argument
	bsrl	buserr_c
	addql	#4,%sp
	jra	.Lret_from_exception

ENTRY(trap)
	SAVE_ALL_INT
	GET_CURRENT(%d0)
	movel	%sp,%sp@-		| stack frame pointer argument
	bsrl	trap_c
	addql	#4,%sp
	jra	.Lret_from_exception

	| After a fork we jump here directly from resume,
	| so that %d1 contains the previous task
	| schedule_tail now used regardless of CONFIG_SMP
ENTRY(ret_from_fork)
	movel	%d1,%sp@-
	jsr	schedule_tail
	addql	#4,%sp
	jra	.Lret_from_exception

do_trace_entry:
	movel	#-ENOSYS,%sp@(PT_OFF_D0)| needed for strace
	subql	#4,%sp
	SAVE_SWITCH_STACK
	jbsr	syscall_trace
	RESTORE_SWITCH_STACK
	addql	#4,%sp
	movel	%sp@(PT_OFF_ORIG_D0),%d0
	cmpl	#NR_syscalls,%d0
	jcs	syscall
badsys:
	movel	#-ENOSYS,%sp@(PT_OFF_D0)
	jra	ret_from_syscall

do_trace_exit:
	subql	#4,%sp
	SAVE_SWITCH_STACK
	jbsr	syscall_trace
	RESTORE_SWITCH_STACK
	addql	#4,%sp
	jra	.Lret_from_exception

ENTRY(ret_from_signal)
	tstb	%curptr@(TASK_INFO+TINFO_FLAGS+2)
	jge	1f
	jbsr	syscall_trace
1:	RESTORE_SWITCH_STACK
	addql	#4,%sp
/* on 68040 complete pending writebacks if any */
#ifdef CONFIG_M68040
	bfextu	%sp@(PT_OFF_FORMATVEC){#0,#4},%d0
	subql	#7,%d0				| bus error frame ?
	jbne	1f
	movel	%sp,%sp@-
	jbsr	berr_040cleanup
	addql	#4,%sp
1:
#endif
	jra	.Lret_from_exception

ENTRY(system_call)
	SAVE_ALL_SYS

	GET_CURRENT(%d1)
	| save top of frame
	movel	%sp,%curptr@(TASK_THREAD+THREAD_ESP0)

	| syscall trace?
	tstb	%curptr@(TASK_INFO+TINFO_FLAGS+2)
	jmi	do_trace_entry
	cmpl	#NR_syscalls,%d0
	jcc	badsys
syscall:
	jbsr	@(sys_call_table,%d0:l:4)@(0)
	movel	%d0,%sp@(PT_OFF_D0)	| save the return value
ret_from_syscall:
	|oriw	#0x0700,%sr
	movew	%curptr@(TASK_INFO+TINFO_FLAGS+2),%d0
	jne	syscall_exit_work
1:	RESTORE_ALL

syscall_exit_work:
	btst	#5,%sp@(PT_OFF_SR)	| check if returning to kernel
	bnes	1b			| if so, skip resched, signals
	lslw	#1,%d0
	jcs	do_trace_exit
	jmi	do_delayed_trace
	lslw	#8,%d0
	jmi	do_signal_return
	pea	resume_userspace
	jra	schedule


ENTRY(ret_from_exception)
.Lret_from_exception:
	btst	#5,%sp@(PT_OFF_SR)	| check if returning to kernel
	bnes	1f			| if so, skip resched, signals
	| 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

resume_userspace:
	moveb	%curptr@(TASK_INFO+TINFO_FLAGS+3),%d0
	jne	exit_work
1:	RESTORE_ALL

exit_work:
	| save top of frame
	movel	%sp,%curptr@(TASK_THREAD+THREAD_ESP0)
	lslb	#1,%d0
	jmi	do_signal_return
	pea	resume_userspace
	jra	schedule


do_signal_return:
	|andw	#ALLOWINT,%sr
	subql	#4,%sp			| dummy return address
	SAVE_SWITCH_STACK
	pea	%sp@(SWITCH_STACK_SIZE)
	bsrl	do_signal
	addql	#4,%sp
	RESTORE_SWITCH_STACK
	addql	#4,%sp
	jbra	resume_userspace

do_delayed_trace:
	bclr	#7,%sp@(PT_OFF_SR)	| clear trace bit in SR
	pea	1			| send SIGTRAP
	movel	%curptr,%sp@-
	pea	LSIGTRAP
	jbsr	send_sig
	addql	#8,%sp
	addql	#4,%sp
	jbra	resume_userspace


/* This is the main interrupt handler for autovector interrupts */

ENTRY(auto_inthandler)
	SAVE_ALL_INT
	GET_CURRENT(%d0)
	addqb	#1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
					|  put exception # in d0
	bfextu	%sp@(PT_OFF_FORMATVEC){#4,#10},%d0
	subw	#VEC_SPUR,%d0

	movel	%sp,%sp@-
	movel	%d0,%sp@-		|  put vector # on stack
auto_irqhandler_fixup = . + 2
	jsr	__m68k_handle_int	|  process the IRQ
	addql	#8,%sp			|  pop parameters off stack

ret_from_interrupt:
	subqb	#1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
	jeq	ret_from_last_interrupt
2:	RESTORE_ALL

	ALIGN
ret_from_last_interrupt:
	moveq	#(~ALLOWINT>>8)&0xff,%d0
	andb	%sp@(PT_OFF_SR),%d0
	jne	2b

	/* check if we need to do software interrupts */
	tstl	irq_stat+CPUSTAT_SOFTIRQ_PENDING
	jeq	.Lret_from_exception
	pea	ret_from_exception
	jra	do_softirq

/* Handler for user defined interrupt vectors */

ENTRY(user_inthandler)
	SAVE_ALL_INT
	GET_CURRENT(%d0)
	addqb	#1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
					|  put exception # in d0
	bfextu	%sp@(PT_OFF_FORMATVEC){#4,#10},%d0
user_irqvec_fixup = . + 2
	subw	#VEC_USER,%d0

	movel	%sp,%sp@-
	movel	%d0,%sp@-		|  put vector # on stack
user_irqhandler_fixup = . + 2
	jsr	__m68k_handle_int	|  process the IRQ
	addql	#8,%sp			|  pop parameters off stack

	subqb	#1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
	jeq	ret_from_last_interrupt
	RESTORE_ALL

/* Handler for uninitialized and spurious interrupts */

ENTRY(bad_inthandler)
	SAVE_ALL_INT
	GET_CURRENT(%d0)
	addqb	#1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)

	movel	%sp,%sp@-
	jsr	handle_badint
	addql	#4,%sp

	subqb	#1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
	jeq	ret_from_last_interrupt
	RESTORE_ALL


ENTRY(sys_fork)
	SAVE_SWITCH_STACK
	pea	%sp@(SWITCH_STACK_SIZE)
	jbsr	m68k_fork
	addql	#4,%sp
	RESTORE_SWITCH_STACK
	rts

ENTRY(sys_clone)
	SAVE_SWITCH_STACK
	pea	%sp@(SWITCH_STACK_SIZE)
	jbsr	m68k_clone
	addql	#4,%sp
	RESTORE_SWITCH_STACK
	rts

ENTRY(sys_vfork)
	SAVE_SWITCH_STACK
	pea	%sp@(SWITCH_STACK_SIZE)
	jbsr	m68k_vfork
	addql	#4,%sp
	RESTORE_SWITCH_STACK
	rts

ENTRY(sys_sigreturn)
	SAVE_SWITCH_STACK
	jbsr	do_sigreturn
	RESTORE_SWITCH_STACK
	rts

ENTRY(sys_rt_sigreturn)
	SAVE_SWITCH_STACK
	jbsr	do_rt_sigreturn
	RESTORE_SWITCH_STACK
	rts

resume:
	/*
	 * 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.
	 */

	/* save sr */
	movew	%sr,%a0@(TASK_THREAD+THREAD_SR)

	/* save fs (sfc,%dfc) (may be pointing to kernel memory) */
	movec	%sfc,%d0
	movew	%d0,%a0@(TASK_THREAD+THREAD_FS)

	/* save usp */
	/* it is better to use a movel here instead of a movew 8*) */
	movec	%usp,%d0
	movel	%d0,%a0@(TASK_THREAD+THREAD_USP)

	/* save non-scratch registers on stack */
	SAVE_SWITCH_STACK

	/* save current kernel stack pointer */
	movel	%sp,%a0@(TASK_THREAD+THREAD_KSP)

	/* save floating point context */
#ifndef CONFIG_M68KFPU_EMU_ONLY
#ifdef CONFIG_M68KFPU_EMU
	tstl	m68k_fputype
	jeq	3f
#endif
	fsave	%a0@(TASK_THREAD+THREAD_FPSTATE)

#if defined(CONFIG_M68060)
#if !defined(CPU_M68060_ONLY)
	btst	#3,m68k_cputype+3
	beqs	1f
#endif
	/* The 060 FPU keeps status in bits 15-8 of the first longword */
	tstb	%a0@(TASK_THREAD+THREAD_FPSTATE+2)
	jeq	3f
#if !defined(CPU_M68060_ONLY)
	jra	2f
#endif
#endif /* CONFIG_M68060 */
#if !defined(CPU_M68060_ONLY)
1:	tstb	%a0@(TASK_THREAD+THREAD_FPSTATE)
	jeq	3f
#endif
2:	fmovemx	%fp0-%fp7,%a0@(TASK_THREAD+THREAD_FPREG)
	fmoveml	%fpcr/%fpsr/%fpiar,%a0@(TASK_THREAD+THREAD_FPCNTL)
3:
#endif	/* CONFIG_M68KFPU_EMU_ONLY */
	/* Return previous task in %d1 */
	movel	%curptr,%d1

	/* switch to new task (a1 contains new task) */
	movel	%a1,%curptr

	/* restore floating point context */
#ifndef CONFIG_M68KFPU_EMU_ONLY
#ifdef CONFIG_M68KFPU_EMU
	tstl	m68k_fputype
	jeq	4f
#endif
#if defined(CONFIG_M68060)
#if !defined(CPU_M68060_ONLY)
	btst	#3,m68k_cputype+3
	beqs	1f
#endif
	/* The 060 FPU keeps status in bits 15-8 of the first longword */
	tstb	%a1@(TASK_THREAD+THREAD_FPSTATE+2)
	jeq	3f
#if !defined(CPU_M68060_ONLY)
	jra	2f
#endif
#endif /* CONFIG_M68060 */
#if !defined(CPU_M68060_ONLY)
1:	tstb	%a1@(TASK_THREAD+THREAD_FPSTATE)
	jeq	3f
#endif
2:	fmovemx	%a1@(TASK_THREAD+THREAD_FPREG),%fp0-%fp7
	fmoveml	%a1@(TASK_THREAD+THREAD_FPCNTL),%fpcr/%fpsr/%fpiar
3:	frestore %a1@(TASK_THREAD+THREAD_FPSTATE)
4:
#endif	/* CONFIG_M68KFPU_EMU_ONLY */

	/* restore the kernel stack pointer */
	movel	%a1@(TASK_THREAD+THREAD_KSP),%sp

	/* restore non-scratch registers */
	RESTORE_SWITCH_STACK

	/* restore user stack pointer */
	movel	%a1@(TASK_THREAD+THREAD_USP),%a0
	movel	%a0,%usp

	/* restore fs (sfc,%dfc) */
	movew	%a1@(TASK_THREAD+THREAD_FS),%a0
	movec	%a0,%sfc
	movec	%a0,%dfc

	/* restore status register */
	movew	%a1@(TASK_THREAD+THREAD_SR),%sr

	rts
Commit	Line	Data
66d857b0 GU	1	/* -- mode: asm --
	2	*
	3	* linux/arch/m68k/kernel/entry.S
	4	*
	5	* Copyright (C) 1991, 1992 Linus Torvalds
	6	*
	7	* This file is subject to the terms and conditions of the GNU General Public
	8	* License. See the file README.legal in the main directory of this archive
	9	* for more details.
	10	*
	11	* Linux/m68k support by Hamish Macdonald
	12	*
	13	* 68060 fixes by Jesper Skov
	14	*
	15	*/
	16
	17	/*
	18	* entry.S contains the system-call and fault low-level handling routines.
	19	* This also contains the timer-interrupt handler, as well as all interrupts
	20	* and faults that can result in a task-switch.
	21	*
	22	* NOTE: This code handles signal-recognition, which happens every time
	23	* after a timer-interrupt and after each system call.
	24	*
	25	*/
	26
	27	/*
	28	* 12/03/96 Jes: Currently we only support m68k single-cpu systems, so
	29	* all pointers that used to be 'current' are now entry
	30	* number 0 in the 'current_set' list.
	31	*
	32	* 6/05/00 RZ: addedd writeback completion after return from sighandler
	33	* for 68040
	34	*/
	35
	36	#include <linux/linkage.h>
	37	#include <asm/entry.h>
	38	#include <asm/errno.h>
	39	#include <asm/setup.h>
	40	#include <asm/segment.h>
	41	#include <asm/traps.h>
	42	#include <asm/unistd.h>
	43
	44	#include <asm/asm-offsets.h>
	45
	46	.globl system_call, buserr, trap, resume
	47	.globl sys_call_table
	48	.globl sys_fork, sys_clone, sys_vfork
	49	.globl ret_from_interrupt, bad_interrupt
	50	.globl auto_irqhandler_fixup
	51	.globl user_irqvec_fixup, user_irqhandler_fixup
	52
	53	.text
	54	ENTRY(buserr)
	55	SAVE_ALL_INT
	56	GET_CURRENT(%d0)
	57	movel %sp,%sp@- \| stack frame pointer argument
	58	bsrl buserr_c
	59	addql #4,%sp
	60	jra .Lret_from_exception
	61
	62	ENTRY(trap)
	63	SAVE_ALL_INT
	64	GET_CURRENT(%d0)
65	movel %sp,%sp@- \| stack frame pointer argument
66	bsrl trap_c
67	addql #4,%sp
68	jra .Lret_from_exception
69
70	\| After a fork we jump here directly from resume,
71	\| so that %d1 contains the previous task
72	\| schedule_tail now used regardless of CONFIG_SMP
73	ENTRY(ret_from_fork)
74	movel %d1,%sp@-
75	jsr schedule_tail
76	addql #4,%sp
77	jra .Lret_from_exception
78
79	do_trace_entry:
80	movel #-ENOSYS,%sp@(PT_OFF_D0)\| needed for strace
81	subql #4,%sp
82	SAVE_SWITCH_STACK
83	jbsr syscall_trace
84	RESTORE_SWITCH_STACK
85	addql #4,%sp
86	movel %sp@(PT_OFF_ORIG_D0),%d0
87	cmpl #NR_syscalls,%d0
88	jcs syscall
89	badsys:
90	movel #-ENOSYS,%sp@(PT_OFF_D0)
91	jra ret_from_syscall
92
93	do_trace_exit:
94	subql #4,%sp
95	SAVE_SWITCH_STACK
96	jbsr syscall_trace
97	RESTORE_SWITCH_STACK
98	addql #4,%sp
99	jra .Lret_from_exception
100
101	ENTRY(ret_from_signal)
102	tstb %curptr@(TASK_INFO+TINFO_FLAGS+2)
103	jge 1f
104	jbsr syscall_trace
105	1: RESTORE_SWITCH_STACK
106	addql #4,%sp
107	/* on 68040 complete pending writebacks if any */
108	#ifdef CONFIG_M68040
109	bfextu %sp@(PT_OFF_FORMATVEC){#0,#4},%d0
110	subql #7,%d0 \| bus error frame ?
111	jbne 1f
112	movel %sp,%sp@-
113	jbsr berr_040cleanup
114	addql #4,%sp
115	1:
116	#endif
117	jra .Lret_from_exception
118
119	ENTRY(system_call)
120	SAVE_ALL_SYS
121
122	GET_CURRENT(%d1)
123	\| save top of frame
124	movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
125
126	\| syscall trace?
127	tstb %curptr@(TASK_INFO+TINFO_FLAGS+2)
128	jmi do_trace_entry
129	cmpl #NR_syscalls,%d0
130	jcc badsys
131	syscall:
132	jbsr @(sys_call_table,%d0:l:4)@(0)
133	movel %d0,%sp@(PT_OFF_D0) \| save the return value
134	ret_from_syscall:
135	\|oriw #0x0700,%sr
136	movew %curptr@(TASK_INFO+TINFO_FLAGS+2),%d0
137	jne syscall_exit_work
138	1: RESTORE_ALL
139
140	syscall_exit_work:
141	btst #5,%sp@(PT_OFF_SR) \| check if returning to kernel
142	bnes 1b \| if so, skip resched, signals
143	lslw #1,%d0
144	jcs do_trace_exit
145	jmi do_delayed_trace
146	lslw #8,%d0
147	jmi do_signal_return
148	pea resume_userspace
149	jra schedule
150
151
152	ENTRY(ret_from_exception)
153	.Lret_from_exception:
154	btst #5,%sp@(PT_OFF_SR) \| check if returning to kernel
155	bnes 1f \| if so, skip resched, signals
156	\| only allow interrupts when we are really the last one on the
157	\| kernel stack, otherwise stack overflow can occur during
158	\| heavy interrupt load
159	andw #ALLOWINT,%sr
160
161	resume_userspace:
162	moveb %curptr@(TASK_INFO+TINFO_FLAGS+3),%d0
163	jne exit_work
164	1: RESTORE_ALL
165
166	exit_work:
167	\| save top of frame
168	movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
169	lslb #1,%d0
170	jmi do_signal_return
171	pea resume_userspace
172	jra schedule
173
174
175	do_signal_return:
176	\|andw #ALLOWINT,%sr
177	subql #4,%sp \| dummy return address
178	SAVE_SWITCH_STACK
179	pea %sp@(SWITCH_STACK_SIZE)
180	bsrl do_signal
181	addql #4,%sp
182	RESTORE_SWITCH_STACK
183	addql #4,%sp
184	jbra resume_userspace
185
186	do_delayed_trace:
187	bclr #7,%sp@(PT_OFF_SR) \| clear trace bit in SR
188	pea 1 \| send SIGTRAP
189	movel %curptr,%sp@-
190	pea LSIGTRAP
191	jbsr send_sig
192	addql #8,%sp
193	addql #4,%sp
194	jbra resume_userspace
195
196
197	/* This is the main interrupt handler for autovector interrupts */
198
199	ENTRY(auto_inthandler)
200	SAVE_ALL_INT
201	GET_CURRENT(%d0)
202	addqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
203	\| put exception # in d0
204	bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
205	subw #VEC_SPUR,%d0
206
207	movel %sp,%sp@-
208	movel %d0,%sp@- \| put vector # on stack
209	auto_irqhandler_fixup = . + 2
210	jsr __m68k_handle_int \| process the IRQ
211	addql #8,%sp \| pop parameters off stack
212
213	ret_from_interrupt:
214	subqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
215	jeq ret_from_last_interrupt
216	2: RESTORE_ALL
217
218	ALIGN
219	ret_from_last_interrupt:
220	moveq #(~ALLOWINT>>8)&0xff,%d0
221	andb %sp@(PT_OFF_SR),%d0
222	jne 2b
223
224	/* check if we need to do software interrupts */
225	tstl irq_stat+CPUSTAT_SOFTIRQ_PENDING
226	jeq .Lret_from_exception
227	pea ret_from_exception
228	jra do_softirq
229
230	/* Handler for user defined interrupt vectors */
231
232	ENTRY(user_inthandler)
233	SAVE_ALL_INT
234	GET_CURRENT(%d0)
235	addqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
236	\| put exception # in d0
237	bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
238	user_irqvec_fixup = . + 2
239	subw #VEC_USER,%d0
240
241	movel %sp,%sp@-
242	movel %d0,%sp@- \| put vector # on stack
243	user_irqhandler_fixup = . + 2
244	jsr __m68k_handle_int \| process the IRQ
245	addql #8,%sp \| pop parameters off stack
246
247	subqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
248	jeq ret_from_last_interrupt
249	RESTORE_ALL
250
251	/* Handler for uninitialized and spurious interrupts */
252
253	ENTRY(bad_inthandler)
254	SAVE_ALL_INT
255	GET_CURRENT(%d0)
256	addqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
257
258	movel %sp,%sp@-
259	jsr handle_badint
260	addql #4,%sp
261
262	subqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1)
263	jeq ret_from_last_interrupt
264	RESTORE_ALL
265
266
267	ENTRY(sys_fork)
268	SAVE_SWITCH_STACK
269	pea %sp@(SWITCH_STACK_SIZE)
270	jbsr m68k_fork
271	addql #4,%sp
272	RESTORE_SWITCH_STACK
273	rts
274
275	ENTRY(sys_clone)
276	SAVE_SWITCH_STACK
277	pea %sp@(SWITCH_STACK_SIZE)
278	jbsr m68k_clone
279	addql #4,%sp
280	RESTORE_SWITCH_STACK
281	rts
282
283	ENTRY(sys_vfork)
284	SAVE_SWITCH_STACK
285	pea %sp@(SWITCH_STACK_SIZE)
286	jbsr m68k_vfork
287	addql #4,%sp
288	RESTORE_SWITCH_STACK
289	rts
290
291	ENTRY(sys_sigreturn)
292	SAVE_SWITCH_STACK
293	jbsr do_sigreturn
294	RESTORE_SWITCH_STACK
295	rts
296
297	ENTRY(sys_rt_sigreturn)
298	SAVE_SWITCH_STACK
299	jbsr do_rt_sigreturn
300	RESTORE_SWITCH_STACK
301	rts
302
303	resume:
304	/*
305	* Beware - when entering resume, prev (the current task) is
306	* in a0, next (the new task) is in a1,so don't change these
307	* registers until their contents are no longer needed.
308	*/
309
310	/* save sr */
311	movew %sr,%a0@(TASK_THREAD+THREAD_SR)
312
313	/* save fs (sfc,%dfc) (may be pointing to kernel memory) */
314	movec %sfc,%d0
315	movew %d0,%a0@(TASK_THREAD+THREAD_FS)
316
317	/* save usp */
318	/* it is better to use a movel here instead of a movew 8) /
319	movec %usp,%d0
320	movel %d0,%a0@(TASK_THREAD+THREAD_USP)
321
322	/* save non-scratch registers on stack */
323	SAVE_SWITCH_STACK
324
325	/* save current kernel stack pointer */
326	movel %sp,%a0@(TASK_THREAD+THREAD_KSP)
327
328	/* save floating point context */
329	#ifndef CONFIG_M68KFPU_EMU_ONLY
330	#ifdef CONFIG_M68KFPU_EMU
331	tstl m68k_fputype
332	jeq 3f
333	#endif
334	fsave %a0@(TASK_THREAD+THREAD_FPSTATE)
335
336	#if defined(CONFIG_M68060)
337	#if !defined(CPU_M68060_ONLY)
338	btst #3,m68k_cputype+3
339	beqs 1f
340	#endif
341	/* The 060 FPU keeps status in bits 15-8 of the first longword */
342	tstb %a0@(TASK_THREAD+THREAD_FPSTATE+2)
343	jeq 3f
344	#if !defined(CPU_M68060_ONLY)
345	jra 2f
346	#endif
347	#endif /* CONFIG_M68060 */
348	#if !defined(CPU_M68060_ONLY)
349	1: tstb %a0@(TASK_THREAD+THREAD_FPSTATE)
350	jeq 3f
351	#endif
352	2: fmovemx %fp0-%fp7,%a0@(TASK_THREAD+THREAD_FPREG)
353	fmoveml %fpcr/%fpsr/%fpiar,%a0@(TASK_THREAD+THREAD_FPCNTL)
354	3:
355	#endif /* CONFIG_M68KFPU_EMU_ONLY */
356	/* Return previous task in %d1 */
357	movel %curptr,%d1
358
359	/* switch to new task (a1 contains new task) */
360	movel %a1,%curptr
361
362	/* restore floating point context */
363	#ifndef CONFIG_M68KFPU_EMU_ONLY
364	#ifdef CONFIG_M68KFPU_EMU
365	tstl m68k_fputype
366	jeq 4f
367	#endif
368	#if defined(CONFIG_M68060)
369	#if !defined(CPU_M68060_ONLY)
370	btst #3,m68k_cputype+3
371	beqs 1f
372	#endif
373	/* The 060 FPU keeps status in bits 15-8 of the first longword */
374	tstb %a1@(TASK_THREAD+THREAD_FPSTATE+2)
375	jeq 3f
376	#if !defined(CPU_M68060_ONLY)
377	jra 2f
378	#endif
379	#endif /* CONFIG_M68060 */
380	#if !defined(CPU_M68060_ONLY)
381	1: tstb %a1@(TASK_THREAD+THREAD_FPSTATE)
382	jeq 3f
383	#endif
384	2: fmovemx %a1@(TASK_THREAD+THREAD_FPREG),%fp0-%fp7
385	fmoveml %a1@(TASK_THREAD+THREAD_FPCNTL),%fpcr/%fpsr/%fpiar
386	3: frestore %a1@(TASK_THREAD+THREAD_FPSTATE)
387	4:
388	#endif /* CONFIG_M68KFPU_EMU_ONLY */
389
390	/* restore the kernel stack pointer */
391	movel %a1@(TASK_THREAD+THREAD_KSP),%sp
392
393	/* restore non-scratch registers */
394	RESTORE_SWITCH_STACK
395
396	/* restore user stack pointer */
397	movel %a1@(TASK_THREAD+THREAD_USP),%a0
398	movel %a0,%usp
399
400	/* restore fs (sfc,%dfc) */
401	movew %a1@(TASK_THREAD+THREAD_FS),%a0
402	movec %a0,%sfc
403	movec %a0,%dfc
404
405	/* restore status register */
406	movew %a1@(TASK_THREAD+THREAD_SR),%sr
407
408	rts
409