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1#ifdef CONFIG_MMU
2#include "entry_mm.S"
3#else
4#include "entry_no.S"
5#endif
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/errno.h>
38#include <asm/setup.h>
39#include <asm/segment.h>
40#include <asm/traps.h>
41#include <asm/unistd.h>
42#include <asm/asm-offsets.h>
43#include <asm/entry.h>
44
45.globl system_call, buserr, trap, resume
46.globl sys_call_table
47.globl __sys_fork, __sys_clone, __sys_vfork
48.globl bad_interrupt
49.globl auto_irqhandler_fixup
50.globl user_irqvec_fixup
51
52.text
53ENTRY(__sys_fork)
54 SAVE_SWITCH_STACK
55 jbsr sys_fork
56 lea %sp@(24),%sp
57 rts
58
59ENTRY(__sys_clone)
60 SAVE_SWITCH_STACK
61 pea %sp@(SWITCH_STACK_SIZE)
62 jbsr m68k_clone
63 lea %sp@(28),%sp
64 rts
65
66ENTRY(__sys_vfork)
67 SAVE_SWITCH_STACK
68 jbsr sys_vfork
69 lea %sp@(24),%sp
70 rts
71
72ENTRY(sys_sigreturn)
73 SAVE_SWITCH_STACK
74 jbsr do_sigreturn
75 RESTORE_SWITCH_STACK
76 rts
77
78ENTRY(sys_rt_sigreturn)
79 SAVE_SWITCH_STACK
80 jbsr do_rt_sigreturn
81 RESTORE_SWITCH_STACK
82 rts
83
84ENTRY(buserr)
85 SAVE_ALL_INT
86 GET_CURRENT(%d0)
87 movel %sp,%sp@- | stack frame pointer argument
88 jbsr buserr_c
89 addql #4,%sp
90 jra ret_from_exception
91
92ENTRY(trap)
93 SAVE_ALL_INT
94 GET_CURRENT(%d0)
95 movel %sp,%sp@- | stack frame pointer argument
96 jbsr trap_c
97 addql #4,%sp
98 jra ret_from_exception
99
100 | After a fork we jump here directly from resume,
101 | so that %d1 contains the previous task
102 | schedule_tail now used regardless of CONFIG_SMP
103ENTRY(ret_from_fork)
104 movel %d1,%sp@-
105 jsr schedule_tail
106 addql #4,%sp
107 jra ret_from_exception
108
109ENTRY(ret_from_kernel_thread)
110 | a3 contains the kernel thread payload, d7 - its argument
111 movel %d1,%sp@-
112 jsr schedule_tail
113 movel %d7,(%sp)
114 jsr %a3@
115 addql #4,%sp
116 jra ret_from_exception
117
118#if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)
119
120#ifdef TRAP_DBG_INTERRUPT
121
122.globl dbginterrupt
123ENTRY(dbginterrupt)
124 SAVE_ALL_INT
125 GET_CURRENT(%d0)
126 movel %sp,%sp@- /* stack frame pointer argument */
127 jsr dbginterrupt_c
128 addql #4,%sp
129 jra ret_from_exception
130#endif
131
132ENTRY(reschedule)
133 /* save top of frame */
134 pea %sp@
135 jbsr set_esp0
136 addql #4,%sp
137 pea ret_from_exception
138 jmp schedule
139
140ENTRY(ret_from_user_signal)
141 moveq #__NR_sigreturn,%d0
142 trap #0
143
144ENTRY(ret_from_user_rt_signal)
145 movel #__NR_rt_sigreturn,%d0
146 trap #0
147
148#else
149
150do_trace_entry:
151 movel #-ENOSYS,%sp@(PT_OFF_D0)| needed for strace
152 subql #4,%sp
153 SAVE_SWITCH_STACK
154 jbsr syscall_trace
155 RESTORE_SWITCH_STACK
156 addql #4,%sp
157 movel %sp@(PT_OFF_ORIG_D0),%d0
158 cmpl #NR_syscalls,%d0
159 jcs syscall
160badsys:
161 movel #-ENOSYS,%sp@(PT_OFF_D0)
162 jra ret_from_syscall
163
164do_trace_exit:
165 subql #4,%sp
166 SAVE_SWITCH_STACK
167 jbsr syscall_trace
168 RESTORE_SWITCH_STACK
169 addql #4,%sp
170 jra .Lret_from_exception
171
172ENTRY(ret_from_signal)
173 movel %curptr@(TASK_STACK),%a1
174 tstb %a1@(TINFO_FLAGS+2)
175 jge 1f
176 jbsr syscall_trace
1771: RESTORE_SWITCH_STACK
178 addql #4,%sp
179/* on 68040 complete pending writebacks if any */
180#ifdef CONFIG_M68040
181 bfextu %sp@(PT_OFF_FORMATVEC){#0,#4},%d0
182 subql #7,%d0 | bus error frame ?
183 jbne 1f
184 movel %sp,%sp@-
185 jbsr berr_040cleanup
186 addql #4,%sp
1871:
188#endif
189 jra .Lret_from_exception
190
191ENTRY(system_call)
192 SAVE_ALL_SYS
193
194 GET_CURRENT(%d1)
195 movel %d1,%a1
196
197 | save top of frame
198 movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
199
200 | syscall trace?
201 tstb %a1@(TINFO_FLAGS+2)
202 jmi do_trace_entry
203 cmpl #NR_syscalls,%d0
204 jcc badsys
205syscall:
206 jbsr @(sys_call_table,%d0:l:4)@(0)
207 movel %d0,%sp@(PT_OFF_D0) | save the return value
208ret_from_syscall:
209 |oriw #0x0700,%sr
210 movel %curptr@(TASK_STACK),%a1
211 movew %a1@(TINFO_FLAGS+2),%d0
212 jne syscall_exit_work
2131: RESTORE_ALL
214
215syscall_exit_work:
216 btst #5,%sp@(PT_OFF_SR) | check if returning to kernel
217 bnes 1b | if so, skip resched, signals
218 lslw #1,%d0
219 jcs do_trace_exit
220 jmi do_delayed_trace
221 lslw #8,%d0
222 jne do_signal_return
223 pea resume_userspace
224 jra schedule
225
226
227ENTRY(ret_from_exception)
228.Lret_from_exception:
229 btst #5,%sp@(PT_OFF_SR) | check if returning to kernel
230 bnes 1f | if so, skip resched, signals
231 | only allow interrupts when we are really the last one on the
232 | kernel stack, otherwise stack overflow can occur during
233 | heavy interrupt load
234 andw #ALLOWINT,%sr
235
236resume_userspace:
237 movel %curptr@(TASK_STACK),%a1
238 moveb %a1@(TINFO_FLAGS+3),%d0
239 jne exit_work
2401: RESTORE_ALL
241
242exit_work:
243 | save top of frame
244 movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
245 lslb #1,%d0
246 jne do_signal_return
247 pea resume_userspace
248 jra schedule
249
250
251do_signal_return:
252 |andw #ALLOWINT,%sr
253 subql #4,%sp | dummy return address
254 SAVE_SWITCH_STACK
255 pea %sp@(SWITCH_STACK_SIZE)
256 bsrl do_notify_resume
257 addql #4,%sp
258 RESTORE_SWITCH_STACK
259 addql #4,%sp
260 jbra resume_userspace
261
262do_delayed_trace:
263 bclr #7,%sp@(PT_OFF_SR) | clear trace bit in SR
264 pea 1 | send SIGTRAP
265 movel %curptr,%sp@-
266 pea LSIGTRAP
267 jbsr send_sig
268 addql #8,%sp
269 addql #4,%sp
270 jbra resume_userspace
271
272
273/* This is the main interrupt handler for autovector interrupts */
274
275ENTRY(auto_inthandler)
276 SAVE_ALL_INT
277 GET_CURRENT(%d0)
278 | put exception # in d0
279 bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
280 subw #VEC_SPUR,%d0
281
282 movel %sp,%sp@-
283 movel %d0,%sp@- | put vector # on stack
284auto_irqhandler_fixup = . + 2
285 jsr do_IRQ | process the IRQ
286 addql #8,%sp | pop parameters off stack
287 jra ret_from_exception
288
289/* Handler for user defined interrupt vectors */
290
291ENTRY(user_inthandler)
292 SAVE_ALL_INT
293 GET_CURRENT(%d0)
294 | put exception # in d0
295 bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
296user_irqvec_fixup = . + 2
297 subw #VEC_USER,%d0
298
299 movel %sp,%sp@-
300 movel %d0,%sp@- | put vector # on stack
301 jsr do_IRQ | process the IRQ
302 addql #8,%sp | pop parameters off stack
303 jra ret_from_exception
304
305/* Handler for uninitialized and spurious interrupts */
306
307ENTRY(bad_inthandler)
308 SAVE_ALL_INT
309 GET_CURRENT(%d0)
310
311 movel %sp,%sp@-
312 jsr handle_badint
313 addql #4,%sp
314 jra ret_from_exception
315
316resume:
317 /*
318 * Beware - when entering resume, prev (the current task) is
319 * in a0, next (the new task) is in a1,so don't change these
320 * registers until their contents are no longer needed.
321 */
322
323 /* save sr */
324 movew %sr,%a0@(TASK_THREAD+THREAD_SR)
325
326 /* save fs (sfc,%dfc) (may be pointing to kernel memory) */
327 movec %sfc,%d0
328 movew %d0,%a0@(TASK_THREAD+THREAD_FS)
329
330 /* save usp */
331 /* it is better to use a movel here instead of a movew 8*) */
332 movec %usp,%d0
333 movel %d0,%a0@(TASK_THREAD+THREAD_USP)
334
335 /* save non-scratch registers on stack */
336 SAVE_SWITCH_STACK
337
338 /* save current kernel stack pointer */
339 movel %sp,%a0@(TASK_THREAD+THREAD_KSP)
340
341 /* save floating point context */
342#ifndef CONFIG_M68KFPU_EMU_ONLY
343#ifdef CONFIG_M68KFPU_EMU
344 tstl m68k_fputype
345 jeq 3f
346#endif
347 fsave %a0@(TASK_THREAD+THREAD_FPSTATE)
348
349#if defined(CONFIG_M68060)
350#if !defined(CPU_M68060_ONLY)
351 btst #3,m68k_cputype+3
352 beqs 1f
353#endif
354 /* The 060 FPU keeps status in bits 15-8 of the first longword */
355 tstb %a0@(TASK_THREAD+THREAD_FPSTATE+2)
356 jeq 3f
357#if !defined(CPU_M68060_ONLY)
358 jra 2f
359#endif
360#endif /* CONFIG_M68060 */
361#if !defined(CPU_M68060_ONLY)
3621: tstb %a0@(TASK_THREAD+THREAD_FPSTATE)
363 jeq 3f
364#endif
3652: fmovemx %fp0-%fp7,%a0@(TASK_THREAD+THREAD_FPREG)
366 fmoveml %fpcr/%fpsr/%fpiar,%a0@(TASK_THREAD+THREAD_FPCNTL)
3673:
368#endif /* CONFIG_M68KFPU_EMU_ONLY */
369 /* Return previous task in %d1 */
370 movel %curptr,%d1
371
372 /* switch to new task (a1 contains new task) */
373 movel %a1,%curptr
374
375 /* restore floating point context */
376#ifndef CONFIG_M68KFPU_EMU_ONLY
377#ifdef CONFIG_M68KFPU_EMU
378 tstl m68k_fputype
379 jeq 4f
380#endif
381#if defined(CONFIG_M68060)
382#if !defined(CPU_M68060_ONLY)
383 btst #3,m68k_cputype+3
384 beqs 1f
385#endif
386 /* The 060 FPU keeps status in bits 15-8 of the first longword */
387 tstb %a1@(TASK_THREAD+THREAD_FPSTATE+2)
388 jeq 3f
389#if !defined(CPU_M68060_ONLY)
390 jra 2f
391#endif
392#endif /* CONFIG_M68060 */
393#if !defined(CPU_M68060_ONLY)
3941: tstb %a1@(TASK_THREAD+THREAD_FPSTATE)
395 jeq 3f
396#endif
3972: fmovemx %a1@(TASK_THREAD+THREAD_FPREG),%fp0-%fp7
398 fmoveml %a1@(TASK_THREAD+THREAD_FPCNTL),%fpcr/%fpsr/%fpiar
3993: frestore %a1@(TASK_THREAD+THREAD_FPSTATE)
4004:
401#endif /* CONFIG_M68KFPU_EMU_ONLY */
402
403 /* restore the kernel stack pointer */
404 movel %a1@(TASK_THREAD+THREAD_KSP),%sp
405
406 /* restore non-scratch registers */
407 RESTORE_SWITCH_STACK
408
409 /* restore user stack pointer */
410 movel %a1@(TASK_THREAD+THREAD_USP),%a0
411 movel %a0,%usp
412
413 /* restore fs (sfc,%dfc) */
414 movew %a1@(TASK_THREAD+THREAD_FS),%a0
415 movec %a0,%sfc
416 movec %a0,%dfc
417
418 /* restore status register */
419 movew %a1@(TASK_THREAD+THREAD_SR),%sr
420
421 rts
422
423#endif /* CONFIG_MMU && !CONFIG_COLDFIRE */