xref: /openbmc/linux/arch/m68k/kernel/signal.c (revision 97da55fc)
1 /*
2  *  linux/arch/m68k/kernel/signal.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  *
6  * This file is subject to the terms and conditions of the GNU General Public
7  * License.  See the file COPYING in the main directory of this archive
8  * for more details.
9  */
10 
11 /*
12  * Linux/m68k support by Hamish Macdonald
13  *
14  * 68060 fixes by Jesper Skov
15  *
16  * 1997-12-01  Modified for POSIX.1b signals by Andreas Schwab
17  *
18  * mathemu support by Roman Zippel
19  *  (Note: fpstate in the signal context is completely ignored for the emulator
20  *         and the internal floating point format is put on stack)
21  */
22 
23 /*
24  * ++roman (07/09/96): implemented signal stacks (specially for tosemu on
25  * Atari :-) Current limitation: Only one sigstack can be active at one time.
26  * If a second signal with SA_ONSTACK set arrives while working on a sigstack,
27  * SA_ONSTACK is ignored. This behaviour avoids lots of trouble with nested
28  * signal handlers!
29  */
30 
31 #include <linux/sched.h>
32 #include <linux/mm.h>
33 #include <linux/kernel.h>
34 #include <linux/signal.h>
35 #include <linux/syscalls.h>
36 #include <linux/errno.h>
37 #include <linux/wait.h>
38 #include <linux/ptrace.h>
39 #include <linux/unistd.h>
40 #include <linux/stddef.h>
41 #include <linux/highuid.h>
42 #include <linux/personality.h>
43 #include <linux/tty.h>
44 #include <linux/binfmts.h>
45 #include <linux/module.h>
46 #include <linux/tracehook.h>
47 
48 #include <asm/setup.h>
49 #include <asm/uaccess.h>
50 #include <asm/pgtable.h>
51 #include <asm/traps.h>
52 #include <asm/ucontext.h>
53 
54 #ifdef CONFIG_MMU
55 
56 /*
57  * Handle the slight differences in classic 68k and ColdFire trap frames.
58  */
59 #ifdef CONFIG_COLDFIRE
60 #define	FORMAT		4
61 #define	FMT4SIZE	0
62 #else
63 #define	FORMAT		0
64 #define	FMT4SIZE	sizeof(((struct frame *)0)->un.fmt4)
65 #endif
66 
67 static const int frame_size_change[16] = {
68   [1]	= -1, /* sizeof(((struct frame *)0)->un.fmt1), */
69   [2]	= sizeof(((struct frame *)0)->un.fmt2),
70   [3]	= sizeof(((struct frame *)0)->un.fmt3),
71   [4]	= FMT4SIZE,
72   [5]	= -1, /* sizeof(((struct frame *)0)->un.fmt5), */
73   [6]	= -1, /* sizeof(((struct frame *)0)->un.fmt6), */
74   [7]	= sizeof(((struct frame *)0)->un.fmt7),
75   [8]	= -1, /* sizeof(((struct frame *)0)->un.fmt8), */
76   [9]	= sizeof(((struct frame *)0)->un.fmt9),
77   [10]	= sizeof(((struct frame *)0)->un.fmta),
78   [11]	= sizeof(((struct frame *)0)->un.fmtb),
79   [12]	= -1, /* sizeof(((struct frame *)0)->un.fmtc), */
80   [13]	= -1, /* sizeof(((struct frame *)0)->un.fmtd), */
81   [14]	= -1, /* sizeof(((struct frame *)0)->un.fmte), */
82   [15]	= -1, /* sizeof(((struct frame *)0)->un.fmtf), */
83 };
84 
85 static inline int frame_extra_sizes(int f)
86 {
87 	return frame_size_change[f];
88 }
89 
90 int handle_kernel_fault(struct pt_regs *regs)
91 {
92 	const struct exception_table_entry *fixup;
93 	struct pt_regs *tregs;
94 
95 	/* Are we prepared to handle this kernel fault? */
96 	fixup = search_exception_tables(regs->pc);
97 	if (!fixup)
98 		return 0;
99 
100 	/* Create a new four word stack frame, discarding the old one. */
101 	regs->stkadj = frame_extra_sizes(regs->format);
102 	tregs =	(struct pt_regs *)((long)regs + regs->stkadj);
103 	tregs->vector = regs->vector;
104 	tregs->format = FORMAT;
105 	tregs->pc = fixup->fixup;
106 	tregs->sr = regs->sr;
107 
108 	return 1;
109 }
110 
111 void ptrace_signal_deliver(void)
112 {
113 	struct pt_regs *regs = signal_pt_regs();
114 	if (regs->orig_d0 < 0)
115 		return;
116 	switch (regs->d0) {
117 	case -ERESTARTNOHAND:
118 	case -ERESTARTSYS:
119 	case -ERESTARTNOINTR:
120 		regs->d0 = regs->orig_d0;
121 		regs->orig_d0 = -1;
122 		regs->pc -= 2;
123 		break;
124 	}
125 }
126 
127 static inline void push_cache (unsigned long vaddr)
128 {
129 	/*
130 	 * Using the old cache_push_v() was really a big waste.
131 	 *
132 	 * What we are trying to do is to flush 8 bytes to ram.
133 	 * Flushing 2 cache lines of 16 bytes is much cheaper than
134 	 * flushing 1 or 2 pages, as previously done in
135 	 * cache_push_v().
136 	 *                                                     Jes
137 	 */
138 	if (CPU_IS_040) {
139 		unsigned long temp;
140 
141 		__asm__ __volatile__ (".chip 68040\n\t"
142 				      "nop\n\t"
143 				      "ptestr (%1)\n\t"
144 				      "movec %%mmusr,%0\n\t"
145 				      ".chip 68k"
146 				      : "=r" (temp)
147 				      : "a" (vaddr));
148 
149 		temp &= PAGE_MASK;
150 		temp |= vaddr & ~PAGE_MASK;
151 
152 		__asm__ __volatile__ (".chip 68040\n\t"
153 				      "nop\n\t"
154 				      "cpushl %%bc,(%0)\n\t"
155 				      ".chip 68k"
156 				      : : "a" (temp));
157 	}
158 	else if (CPU_IS_060) {
159 		unsigned long temp;
160 		__asm__ __volatile__ (".chip 68060\n\t"
161 				      "plpar (%0)\n\t"
162 				      ".chip 68k"
163 				      : "=a" (temp)
164 				      : "0" (vaddr));
165 		__asm__ __volatile__ (".chip 68060\n\t"
166 				      "cpushl %%bc,(%0)\n\t"
167 				      ".chip 68k"
168 				      : : "a" (temp));
169 	} else if (!CPU_IS_COLDFIRE) {
170 		/*
171 		 * 68030/68020 have no writeback cache;
172 		 * still need to clear icache.
173 		 * Note that vaddr is guaranteed to be long word aligned.
174 		 */
175 		unsigned long temp;
176 		asm volatile ("movec %%cacr,%0" : "=r" (temp));
177 		temp += 4;
178 		asm volatile ("movec %0,%%caar\n\t"
179 			      "movec %1,%%cacr"
180 			      : : "r" (vaddr), "r" (temp));
181 		asm volatile ("movec %0,%%caar\n\t"
182 			      "movec %1,%%cacr"
183 			      : : "r" (vaddr + 4), "r" (temp));
184 	}
185 }
186 
187 static inline void adjustformat(struct pt_regs *regs)
188 {
189 }
190 
191 static inline void save_a5_state(struct sigcontext *sc, struct pt_regs *regs)
192 {
193 }
194 
195 #else /* CONFIG_MMU */
196 
197 void ret_from_user_signal(void);
198 void ret_from_user_rt_signal(void);
199 
200 static inline int frame_extra_sizes(int f)
201 {
202 	/* No frame size adjustments required on non-MMU CPUs */
203 	return 0;
204 }
205 
206 static inline void adjustformat(struct pt_regs *regs)
207 {
208 	((struct switch_stack *)regs - 1)->a5 = current->mm->start_data;
209 	/*
210 	 * set format byte to make stack appear modulo 4, which it will
211 	 * be when doing the rte
212 	 */
213 	regs->format = 0x4;
214 }
215 
216 static inline void save_a5_state(struct sigcontext *sc, struct pt_regs *regs)
217 {
218 	sc->sc_a5 = ((struct switch_stack *)regs - 1)->a5;
219 }
220 
221 static inline void push_cache(unsigned long vaddr)
222 {
223 }
224 
225 #endif /* CONFIG_MMU */
226 
227 /*
228  * Do a signal return; undo the signal stack.
229  *
230  * Keep the return code on the stack quadword aligned!
231  * That makes the cache flush below easier.
232  */
233 
234 struct sigframe
235 {
236 	char __user *pretcode;
237 	int sig;
238 	int code;
239 	struct sigcontext __user *psc;
240 	char retcode[8];
241 	unsigned long extramask[_NSIG_WORDS-1];
242 	struct sigcontext sc;
243 };
244 
245 struct rt_sigframe
246 {
247 	char __user *pretcode;
248 	int sig;
249 	struct siginfo __user *pinfo;
250 	void __user *puc;
251 	char retcode[8];
252 	struct siginfo info;
253 	struct ucontext uc;
254 };
255 
256 #define FPCONTEXT_SIZE	216
257 #define uc_fpstate	uc_filler[0]
258 #define uc_formatvec	uc_filler[FPCONTEXT_SIZE/4]
259 #define uc_extra	uc_filler[FPCONTEXT_SIZE/4+1]
260 
261 #ifdef CONFIG_FPU
262 
263 static unsigned char fpu_version;	/* version number of fpu, set by setup_frame */
264 
265 static inline int restore_fpu_state(struct sigcontext *sc)
266 {
267 	int err = 1;
268 
269 	if (FPU_IS_EMU) {
270 	    /* restore registers */
271 	    memcpy(current->thread.fpcntl, sc->sc_fpcntl, 12);
272 	    memcpy(current->thread.fp, sc->sc_fpregs, 24);
273 	    return 0;
274 	}
275 
276 	if (CPU_IS_060 ? sc->sc_fpstate[2] : sc->sc_fpstate[0]) {
277 	    /* Verify the frame format.  */
278 	    if (!(CPU_IS_060 || CPU_IS_COLDFIRE) &&
279 		 (sc->sc_fpstate[0] != fpu_version))
280 		goto out;
281 	    if (CPU_IS_020_OR_030) {
282 		if (m68k_fputype & FPU_68881 &&
283 		    !(sc->sc_fpstate[1] == 0x18 || sc->sc_fpstate[1] == 0xb4))
284 		    goto out;
285 		if (m68k_fputype & FPU_68882 &&
286 		    !(sc->sc_fpstate[1] == 0x38 || sc->sc_fpstate[1] == 0xd4))
287 		    goto out;
288 	    } else if (CPU_IS_040) {
289 		if (!(sc->sc_fpstate[1] == 0x00 ||
290                       sc->sc_fpstate[1] == 0x28 ||
291                       sc->sc_fpstate[1] == 0x60))
292 		    goto out;
293 	    } else if (CPU_IS_060) {
294 		if (!(sc->sc_fpstate[3] == 0x00 ||
295                       sc->sc_fpstate[3] == 0x60 ||
296 		      sc->sc_fpstate[3] == 0xe0))
297 		    goto out;
298 	    } else if (CPU_IS_COLDFIRE) {
299 		if (!(sc->sc_fpstate[0] == 0x00 ||
300 		      sc->sc_fpstate[0] == 0x05 ||
301 		      sc->sc_fpstate[0] == 0xe5))
302 		    goto out;
303 	    } else
304 		goto out;
305 
306 	    if (CPU_IS_COLDFIRE) {
307 		__asm__ volatile ("fmovemd %0,%%fp0-%%fp1\n\t"
308 				  "fmovel %1,%%fpcr\n\t"
309 				  "fmovel %2,%%fpsr\n\t"
310 				  "fmovel %3,%%fpiar"
311 				  : /* no outputs */
312 				  : "m" (sc->sc_fpregs[0]),
313 				    "m" (sc->sc_fpcntl[0]),
314 				    "m" (sc->sc_fpcntl[1]),
315 				    "m" (sc->sc_fpcntl[2]));
316 	    } else {
317 		__asm__ volatile (".chip 68k/68881\n\t"
318 				  "fmovemx %0,%%fp0-%%fp1\n\t"
319 				  "fmoveml %1,%%fpcr/%%fpsr/%%fpiar\n\t"
320 				  ".chip 68k"
321 				  : /* no outputs */
322 				  : "m" (*sc->sc_fpregs),
323 				    "m" (*sc->sc_fpcntl));
324 	    }
325 	}
326 
327 	if (CPU_IS_COLDFIRE) {
328 		__asm__ volatile ("frestore %0" : : "m" (*sc->sc_fpstate));
329 	} else {
330 		__asm__ volatile (".chip 68k/68881\n\t"
331 				  "frestore %0\n\t"
332 				  ".chip 68k"
333 				  : : "m" (*sc->sc_fpstate));
334 	}
335 	err = 0;
336 
337 out:
338 	return err;
339 }
340 
341 static inline int rt_restore_fpu_state(struct ucontext __user *uc)
342 {
343 	unsigned char fpstate[FPCONTEXT_SIZE];
344 	int context_size = CPU_IS_060 ? 8 : (CPU_IS_COLDFIRE ? 12 : 0);
345 	fpregset_t fpregs;
346 	int err = 1;
347 
348 	if (FPU_IS_EMU) {
349 		/* restore fpu control register */
350 		if (__copy_from_user(current->thread.fpcntl,
351 				uc->uc_mcontext.fpregs.f_fpcntl, 12))
352 			goto out;
353 		/* restore all other fpu register */
354 		if (__copy_from_user(current->thread.fp,
355 				uc->uc_mcontext.fpregs.f_fpregs, 96))
356 			goto out;
357 		return 0;
358 	}
359 
360 	if (__get_user(*(long *)fpstate, (long __user *)&uc->uc_fpstate))
361 		goto out;
362 	if (CPU_IS_060 ? fpstate[2] : fpstate[0]) {
363 		if (!(CPU_IS_060 || CPU_IS_COLDFIRE))
364 			context_size = fpstate[1];
365 		/* Verify the frame format.  */
366 		if (!(CPU_IS_060 || CPU_IS_COLDFIRE) &&
367 		     (fpstate[0] != fpu_version))
368 			goto out;
369 		if (CPU_IS_020_OR_030) {
370 			if (m68k_fputype & FPU_68881 &&
371 			    !(context_size == 0x18 || context_size == 0xb4))
372 				goto out;
373 			if (m68k_fputype & FPU_68882 &&
374 			    !(context_size == 0x38 || context_size == 0xd4))
375 				goto out;
376 		} else if (CPU_IS_040) {
377 			if (!(context_size == 0x00 ||
378 			      context_size == 0x28 ||
379 			      context_size == 0x60))
380 				goto out;
381 		} else if (CPU_IS_060) {
382 			if (!(fpstate[3] == 0x00 ||
383 			      fpstate[3] == 0x60 ||
384 			      fpstate[3] == 0xe0))
385 				goto out;
386 		} else if (CPU_IS_COLDFIRE) {
387 			if (!(fpstate[3] == 0x00 ||
388 			      fpstate[3] == 0x05 ||
389 			      fpstate[3] == 0xe5))
390 				goto out;
391 		} else
392 			goto out;
393 		if (__copy_from_user(&fpregs, &uc->uc_mcontext.fpregs,
394 				     sizeof(fpregs)))
395 			goto out;
396 
397 		if (CPU_IS_COLDFIRE) {
398 			__asm__ volatile ("fmovemd %0,%%fp0-%%fp7\n\t"
399 					  "fmovel %1,%%fpcr\n\t"
400 					  "fmovel %2,%%fpsr\n\t"
401 					  "fmovel %3,%%fpiar"
402 					  : /* no outputs */
403 					  : "m" (fpregs.f_fpregs[0]),
404 					    "m" (fpregs.f_fpcntl[0]),
405 					    "m" (fpregs.f_fpcntl[1]),
406 					    "m" (fpregs.f_fpcntl[2]));
407 		} else {
408 			__asm__ volatile (".chip 68k/68881\n\t"
409 					  "fmovemx %0,%%fp0-%%fp7\n\t"
410 					  "fmoveml %1,%%fpcr/%%fpsr/%%fpiar\n\t"
411 					  ".chip 68k"
412 					  : /* no outputs */
413 					  : "m" (*fpregs.f_fpregs),
414 					    "m" (*fpregs.f_fpcntl));
415 		}
416 	}
417 	if (context_size &&
418 	    __copy_from_user(fpstate + 4, (long __user *)&uc->uc_fpstate + 1,
419 			     context_size))
420 		goto out;
421 
422 	if (CPU_IS_COLDFIRE) {
423 		__asm__ volatile ("frestore %0" : : "m" (*fpstate));
424 	} else {
425 		__asm__ volatile (".chip 68k/68881\n\t"
426 				  "frestore %0\n\t"
427 				  ".chip 68k"
428 				  : : "m" (*fpstate));
429 	}
430 	err = 0;
431 
432 out:
433 	return err;
434 }
435 
436 /*
437  * Set up a signal frame.
438  */
439 static inline void save_fpu_state(struct sigcontext *sc, struct pt_regs *regs)
440 {
441 	if (FPU_IS_EMU) {
442 		/* save registers */
443 		memcpy(sc->sc_fpcntl, current->thread.fpcntl, 12);
444 		memcpy(sc->sc_fpregs, current->thread.fp, 24);
445 		return;
446 	}
447 
448 	if (CPU_IS_COLDFIRE) {
449 		__asm__ volatile ("fsave %0"
450 				  : : "m" (*sc->sc_fpstate) : "memory");
451 	} else {
452 		__asm__ volatile (".chip 68k/68881\n\t"
453 				  "fsave %0\n\t"
454 				  ".chip 68k"
455 				  : : "m" (*sc->sc_fpstate) : "memory");
456 	}
457 
458 	if (CPU_IS_060 ? sc->sc_fpstate[2] : sc->sc_fpstate[0]) {
459 		fpu_version = sc->sc_fpstate[0];
460 		if (CPU_IS_020_OR_030 &&
461 		    regs->vector >= (VEC_FPBRUC * 4) &&
462 		    regs->vector <= (VEC_FPNAN * 4)) {
463 			/* Clear pending exception in 68882 idle frame */
464 			if (*(unsigned short *) sc->sc_fpstate == 0x1f38)
465 				sc->sc_fpstate[0x38] |= 1 << 3;
466 		}
467 
468 		if (CPU_IS_COLDFIRE) {
469 			__asm__ volatile ("fmovemd %%fp0-%%fp1,%0\n\t"
470 					  "fmovel %%fpcr,%1\n\t"
471 					  "fmovel %%fpsr,%2\n\t"
472 					  "fmovel %%fpiar,%3"
473 					  : "=m" (sc->sc_fpregs[0]),
474 					    "=m" (sc->sc_fpcntl[0]),
475 					    "=m" (sc->sc_fpcntl[1]),
476 					    "=m" (sc->sc_fpcntl[2])
477 					  : /* no inputs */
478 					  : "memory");
479 		} else {
480 			__asm__ volatile (".chip 68k/68881\n\t"
481 					  "fmovemx %%fp0-%%fp1,%0\n\t"
482 					  "fmoveml %%fpcr/%%fpsr/%%fpiar,%1\n\t"
483 					  ".chip 68k"
484 					  : "=m" (*sc->sc_fpregs),
485 					    "=m" (*sc->sc_fpcntl)
486 					  : /* no inputs */
487 					  : "memory");
488 		}
489 	}
490 }
491 
492 static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs *regs)
493 {
494 	unsigned char fpstate[FPCONTEXT_SIZE];
495 	int context_size = CPU_IS_060 ? 8 : (CPU_IS_COLDFIRE ? 12 : 0);
496 	int err = 0;
497 
498 	if (FPU_IS_EMU) {
499 		/* save fpu control register */
500 		err |= copy_to_user(uc->uc_mcontext.fpregs.f_fpcntl,
501 				current->thread.fpcntl, 12);
502 		/* save all other fpu register */
503 		err |= copy_to_user(uc->uc_mcontext.fpregs.f_fpregs,
504 				current->thread.fp, 96);
505 		return err;
506 	}
507 
508 	if (CPU_IS_COLDFIRE) {
509 		__asm__ volatile ("fsave %0" : : "m" (*fpstate) : "memory");
510 	} else {
511 		__asm__ volatile (".chip 68k/68881\n\t"
512 				  "fsave %0\n\t"
513 				  ".chip 68k"
514 				  : : "m" (*fpstate) : "memory");
515 	}
516 
517 	err |= __put_user(*(long *)fpstate, (long __user *)&uc->uc_fpstate);
518 	if (CPU_IS_060 ? fpstate[2] : fpstate[0]) {
519 		fpregset_t fpregs;
520 		if (!(CPU_IS_060 || CPU_IS_COLDFIRE))
521 			context_size = fpstate[1];
522 		fpu_version = fpstate[0];
523 		if (CPU_IS_020_OR_030 &&
524 		    regs->vector >= (VEC_FPBRUC * 4) &&
525 		    regs->vector <= (VEC_FPNAN * 4)) {
526 			/* Clear pending exception in 68882 idle frame */
527 			if (*(unsigned short *) fpstate == 0x1f38)
528 				fpstate[0x38] |= 1 << 3;
529 		}
530 		if (CPU_IS_COLDFIRE) {
531 			__asm__ volatile ("fmovemd %%fp0-%%fp7,%0\n\t"
532 					  "fmovel %%fpcr,%1\n\t"
533 					  "fmovel %%fpsr,%2\n\t"
534 					  "fmovel %%fpiar,%3"
535 					  : "=m" (fpregs.f_fpregs[0]),
536 					    "=m" (fpregs.f_fpcntl[0]),
537 					    "=m" (fpregs.f_fpcntl[1]),
538 					    "=m" (fpregs.f_fpcntl[2])
539 					  : /* no inputs */
540 					  : "memory");
541 		} else {
542 			__asm__ volatile (".chip 68k/68881\n\t"
543 					  "fmovemx %%fp0-%%fp7,%0\n\t"
544 					  "fmoveml %%fpcr/%%fpsr/%%fpiar,%1\n\t"
545 					  ".chip 68k"
546 					  : "=m" (*fpregs.f_fpregs),
547 					    "=m" (*fpregs.f_fpcntl)
548 					  : /* no inputs */
549 					  : "memory");
550 		}
551 		err |= copy_to_user(&uc->uc_mcontext.fpregs, &fpregs,
552 				    sizeof(fpregs));
553 	}
554 	if (context_size)
555 		err |= copy_to_user((long __user *)&uc->uc_fpstate + 1, fpstate + 4,
556 				    context_size);
557 	return err;
558 }
559 
560 #else /* CONFIG_FPU */
561 
562 /*
563  * For the case with no FPU configured these all do nothing.
564  */
565 static inline int restore_fpu_state(struct sigcontext *sc)
566 {
567 	return 0;
568 }
569 
570 static inline int rt_restore_fpu_state(struct ucontext __user *uc)
571 {
572 	return 0;
573 }
574 
575 static inline void save_fpu_state(struct sigcontext *sc, struct pt_regs *regs)
576 {
577 }
578 
579 static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs *regs)
580 {
581 	return 0;
582 }
583 
584 #endif /* CONFIG_FPU */
585 
586 static int mangle_kernel_stack(struct pt_regs *regs, int formatvec,
587 			       void __user *fp)
588 {
589 	int fsize = frame_extra_sizes(formatvec >> 12);
590 	if (fsize < 0) {
591 		/*
592 		 * user process trying to return with weird frame format
593 		 */
594 #ifdef DEBUG
595 		printk("user process returning with weird frame format\n");
596 #endif
597 		return 1;
598 	}
599 	if (!fsize) {
600 		regs->format = formatvec >> 12;
601 		regs->vector = formatvec & 0xfff;
602 	} else {
603 		struct switch_stack *sw = (struct switch_stack *)regs - 1;
604 		unsigned long buf[fsize / 2]; /* yes, twice as much */
605 
606 		/* that'll make sure that expansion won't crap over data */
607 		if (copy_from_user(buf + fsize / 4, fp, fsize))
608 			return 1;
609 
610 		/* point of no return */
611 		regs->format = formatvec >> 12;
612 		regs->vector = formatvec & 0xfff;
613 #define frame_offset (sizeof(struct pt_regs)+sizeof(struct switch_stack))
614 		__asm__ __volatile__ (
615 #ifdef CONFIG_COLDFIRE
616 			 "   movel %0,%/sp\n\t"
617 			 "   bra ret_from_signal\n"
618 #else
619 			 "   movel %0,%/a0\n\t"
620 			 "   subl %1,%/a0\n\t"     /* make room on stack */
621 			 "   movel %/a0,%/sp\n\t"  /* set stack pointer */
622 			 /* move switch_stack and pt_regs */
623 			 "1: movel %0@+,%/a0@+\n\t"
624 			 "   dbra %2,1b\n\t"
625 			 "   lea %/sp@(%c3),%/a0\n\t" /* add offset of fmt */
626 			 "   lsrl  #2,%1\n\t"
627 			 "   subql #1,%1\n\t"
628 			 /* copy to the gap we'd made */
629 			 "2: movel %4@+,%/a0@+\n\t"
630 			 "   dbra %1,2b\n\t"
631 			 "   bral ret_from_signal\n"
632 #endif
633 			 : /* no outputs, it doesn't ever return */
634 			 : "a" (sw), "d" (fsize), "d" (frame_offset/4-1),
635 			   "n" (frame_offset), "a" (buf + fsize/4)
636 			 : "a0");
637 #undef frame_offset
638 	}
639 	return 0;
640 }
641 
642 static inline int
643 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __user *fp)
644 {
645 	int formatvec;
646 	struct sigcontext context;
647 	int err = 0;
648 
649 	/* Always make any pending restarted system calls return -EINTR */
650 	current_thread_info()->restart_block.fn = do_no_restart_syscall;
651 
652 	/* get previous context */
653 	if (copy_from_user(&context, usc, sizeof(context)))
654 		goto badframe;
655 
656 	/* restore passed registers */
657 	regs->d0 = context.sc_d0;
658 	regs->d1 = context.sc_d1;
659 	regs->a0 = context.sc_a0;
660 	regs->a1 = context.sc_a1;
661 	regs->sr = (regs->sr & 0xff00) | (context.sc_sr & 0xff);
662 	regs->pc = context.sc_pc;
663 	regs->orig_d0 = -1;		/* disable syscall checks */
664 	wrusp(context.sc_usp);
665 	formatvec = context.sc_formatvec;
666 
667 	err = restore_fpu_state(&context);
668 
669 	if (err || mangle_kernel_stack(regs, formatvec, fp))
670 		goto badframe;
671 
672 	return 0;
673 
674 badframe:
675 	return 1;
676 }
677 
678 static inline int
679 rt_restore_ucontext(struct pt_regs *regs, struct switch_stack *sw,
680 		    struct ucontext __user *uc)
681 {
682 	int temp;
683 	greg_t __user *gregs = uc->uc_mcontext.gregs;
684 	unsigned long usp;
685 	int err;
686 
687 	/* Always make any pending restarted system calls return -EINTR */
688 	current_thread_info()->restart_block.fn = do_no_restart_syscall;
689 
690 	err = __get_user(temp, &uc->uc_mcontext.version);
691 	if (temp != MCONTEXT_VERSION)
692 		goto badframe;
693 	/* restore passed registers */
694 	err |= __get_user(regs->d0, &gregs[0]);
695 	err |= __get_user(regs->d1, &gregs[1]);
696 	err |= __get_user(regs->d2, &gregs[2]);
697 	err |= __get_user(regs->d3, &gregs[3]);
698 	err |= __get_user(regs->d4, &gregs[4]);
699 	err |= __get_user(regs->d5, &gregs[5]);
700 	err |= __get_user(sw->d6, &gregs[6]);
701 	err |= __get_user(sw->d7, &gregs[7]);
702 	err |= __get_user(regs->a0, &gregs[8]);
703 	err |= __get_user(regs->a1, &gregs[9]);
704 	err |= __get_user(regs->a2, &gregs[10]);
705 	err |= __get_user(sw->a3, &gregs[11]);
706 	err |= __get_user(sw->a4, &gregs[12]);
707 	err |= __get_user(sw->a5, &gregs[13]);
708 	err |= __get_user(sw->a6, &gregs[14]);
709 	err |= __get_user(usp, &gregs[15]);
710 	wrusp(usp);
711 	err |= __get_user(regs->pc, &gregs[16]);
712 	err |= __get_user(temp, &gregs[17]);
713 	regs->sr = (regs->sr & 0xff00) | (temp & 0xff);
714 	regs->orig_d0 = -1;		/* disable syscall checks */
715 	err |= __get_user(temp, &uc->uc_formatvec);
716 
717 	err |= rt_restore_fpu_state(uc);
718 	err |= restore_altstack(&uc->uc_stack);
719 
720 	if (err)
721 		goto badframe;
722 
723 	if (mangle_kernel_stack(regs, temp, &uc->uc_extra))
724 		goto badframe;
725 
726 	return 0;
727 
728 badframe:
729 	return 1;
730 }
731 
732 asmlinkage int do_sigreturn(unsigned long __unused)
733 {
734 	struct switch_stack *sw = (struct switch_stack *) &__unused;
735 	struct pt_regs *regs = (struct pt_regs *) (sw + 1);
736 	unsigned long usp = rdusp();
737 	struct sigframe __user *frame = (struct sigframe __user *)(usp - 4);
738 	sigset_t set;
739 
740 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
741 		goto badframe;
742 	if (__get_user(set.sig[0], &frame->sc.sc_mask) ||
743 	    (_NSIG_WORDS > 1 &&
744 	     __copy_from_user(&set.sig[1], &frame->extramask,
745 			      sizeof(frame->extramask))))
746 		goto badframe;
747 
748 	set_current_blocked(&set);
749 
750 	if (restore_sigcontext(regs, &frame->sc, frame + 1))
751 		goto badframe;
752 	return regs->d0;
753 
754 badframe:
755 	force_sig(SIGSEGV, current);
756 	return 0;
757 }
758 
759 asmlinkage int do_rt_sigreturn(unsigned long __unused)
760 {
761 	struct switch_stack *sw = (struct switch_stack *) &__unused;
762 	struct pt_regs *regs = (struct pt_regs *) (sw + 1);
763 	unsigned long usp = rdusp();
764 	struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(usp - 4);
765 	sigset_t set;
766 
767 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
768 		goto badframe;
769 	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
770 		goto badframe;
771 
772 	set_current_blocked(&set);
773 
774 	if (rt_restore_ucontext(regs, sw, &frame->uc))
775 		goto badframe;
776 	return regs->d0;
777 
778 badframe:
779 	force_sig(SIGSEGV, current);
780 	return 0;
781 }
782 
783 static void setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
784 			     unsigned long mask)
785 {
786 	sc->sc_mask = mask;
787 	sc->sc_usp = rdusp();
788 	sc->sc_d0 = regs->d0;
789 	sc->sc_d1 = regs->d1;
790 	sc->sc_a0 = regs->a0;
791 	sc->sc_a1 = regs->a1;
792 	sc->sc_sr = regs->sr;
793 	sc->sc_pc = regs->pc;
794 	sc->sc_formatvec = regs->format << 12 | regs->vector;
795 	save_a5_state(sc, regs);
796 	save_fpu_state(sc, regs);
797 }
798 
799 static inline int rt_setup_ucontext(struct ucontext __user *uc, struct pt_regs *regs)
800 {
801 	struct switch_stack *sw = (struct switch_stack *)regs - 1;
802 	greg_t __user *gregs = uc->uc_mcontext.gregs;
803 	int err = 0;
804 
805 	err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
806 	err |= __put_user(regs->d0, &gregs[0]);
807 	err |= __put_user(regs->d1, &gregs[1]);
808 	err |= __put_user(regs->d2, &gregs[2]);
809 	err |= __put_user(regs->d3, &gregs[3]);
810 	err |= __put_user(regs->d4, &gregs[4]);
811 	err |= __put_user(regs->d5, &gregs[5]);
812 	err |= __put_user(sw->d6, &gregs[6]);
813 	err |= __put_user(sw->d7, &gregs[7]);
814 	err |= __put_user(regs->a0, &gregs[8]);
815 	err |= __put_user(regs->a1, &gregs[9]);
816 	err |= __put_user(regs->a2, &gregs[10]);
817 	err |= __put_user(sw->a3, &gregs[11]);
818 	err |= __put_user(sw->a4, &gregs[12]);
819 	err |= __put_user(sw->a5, &gregs[13]);
820 	err |= __put_user(sw->a6, &gregs[14]);
821 	err |= __put_user(rdusp(), &gregs[15]);
822 	err |= __put_user(regs->pc, &gregs[16]);
823 	err |= __put_user(regs->sr, &gregs[17]);
824 	err |= __put_user((regs->format << 12) | regs->vector, &uc->uc_formatvec);
825 	err |= rt_save_fpu_state(uc, regs);
826 	return err;
827 }
828 
829 static inline void __user *
830 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
831 {
832 	unsigned long usp;
833 
834 	/* Default to using normal stack.  */
835 	usp = rdusp();
836 
837 	/* This is the X/Open sanctioned signal stack switching.  */
838 	if (ka->sa.sa_flags & SA_ONSTACK) {
839 		if (!sas_ss_flags(usp))
840 			usp = current->sas_ss_sp + current->sas_ss_size;
841 	}
842 	return (void __user *)((usp - frame_size) & -8UL);
843 }
844 
845 static int setup_frame (int sig, struct k_sigaction *ka,
846 			 sigset_t *set, struct pt_regs *regs)
847 {
848 	struct sigframe __user *frame;
849 	int fsize = frame_extra_sizes(regs->format);
850 	struct sigcontext context;
851 	int err = 0;
852 
853 	if (fsize < 0) {
854 #ifdef DEBUG
855 		printk ("setup_frame: Unknown frame format %#x\n",
856 			regs->format);
857 #endif
858 		goto give_sigsegv;
859 	}
860 
861 	frame = get_sigframe(ka, regs, sizeof(*frame) + fsize);
862 
863 	if (fsize)
864 		err |= copy_to_user (frame + 1, regs + 1, fsize);
865 
866 	err |= __put_user((current_thread_info()->exec_domain
867 			   && current_thread_info()->exec_domain->signal_invmap
868 			   && sig < 32
869 			   ? current_thread_info()->exec_domain->signal_invmap[sig]
870 			   : sig),
871 			  &frame->sig);
872 
873 	err |= __put_user(regs->vector, &frame->code);
874 	err |= __put_user(&frame->sc, &frame->psc);
875 
876 	if (_NSIG_WORDS > 1)
877 		err |= copy_to_user(frame->extramask, &set->sig[1],
878 				    sizeof(frame->extramask));
879 
880 	setup_sigcontext(&context, regs, set->sig[0]);
881 	err |= copy_to_user (&frame->sc, &context, sizeof(context));
882 
883 	/* Set up to return from userspace.  */
884 #ifdef CONFIG_MMU
885 	err |= __put_user(frame->retcode, &frame->pretcode);
886 	/* moveq #,d0; trap #0 */
887 	err |= __put_user(0x70004e40 + (__NR_sigreturn << 16),
888 			  (long __user *)(frame->retcode));
889 #else
890 	err |= __put_user((void *) ret_from_user_signal, &frame->pretcode);
891 #endif
892 
893 	if (err)
894 		goto give_sigsegv;
895 
896 	push_cache ((unsigned long) &frame->retcode);
897 
898 	/*
899 	 * Set up registers for signal handler.  All the state we are about
900 	 * to destroy is successfully copied to sigframe.
901 	 */
902 	wrusp ((unsigned long) frame);
903 	regs->pc = (unsigned long) ka->sa.sa_handler;
904 	adjustformat(regs);
905 
906 	/*
907 	 * This is subtle; if we build more than one sigframe, all but the
908 	 * first one will see frame format 0 and have fsize == 0, so we won't
909 	 * screw stkadj.
910 	 */
911 	if (fsize)
912 		regs->stkadj = fsize;
913 
914 	/* Prepare to skip over the extra stuff in the exception frame.  */
915 	if (regs->stkadj) {
916 		struct pt_regs *tregs =
917 			(struct pt_regs *)((ulong)regs + regs->stkadj);
918 #ifdef DEBUG
919 		printk("Performing stackadjust=%04x\n", regs->stkadj);
920 #endif
921 		/* This must be copied with decreasing addresses to
922                    handle overlaps.  */
923 		tregs->vector = 0;
924 		tregs->format = 0;
925 		tregs->pc = regs->pc;
926 		tregs->sr = regs->sr;
927 	}
928 	return 0;
929 
930 give_sigsegv:
931 	force_sigsegv(sig, current);
932 	return err;
933 }
934 
935 static int setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
936 			    sigset_t *set, struct pt_regs *regs)
937 {
938 	struct rt_sigframe __user *frame;
939 	int fsize = frame_extra_sizes(regs->format);
940 	int err = 0;
941 
942 	if (fsize < 0) {
943 #ifdef DEBUG
944 		printk ("setup_frame: Unknown frame format %#x\n",
945 			regs->format);
946 #endif
947 		goto give_sigsegv;
948 	}
949 
950 	frame = get_sigframe(ka, regs, sizeof(*frame));
951 
952 	if (fsize)
953 		err |= copy_to_user (&frame->uc.uc_extra, regs + 1, fsize);
954 
955 	err |= __put_user((current_thread_info()->exec_domain
956 			   && current_thread_info()->exec_domain->signal_invmap
957 			   && sig < 32
958 			   ? current_thread_info()->exec_domain->signal_invmap[sig]
959 			   : sig),
960 			  &frame->sig);
961 	err |= __put_user(&frame->info, &frame->pinfo);
962 	err |= __put_user(&frame->uc, &frame->puc);
963 	err |= copy_siginfo_to_user(&frame->info, info);
964 
965 	/* Create the ucontext.  */
966 	err |= __put_user(0, &frame->uc.uc_flags);
967 	err |= __put_user(NULL, &frame->uc.uc_link);
968 	err |= __save_altstack(&frame->uc.uc_stack, rdusp());
969 	err |= rt_setup_ucontext(&frame->uc, regs);
970 	err |= copy_to_user (&frame->uc.uc_sigmask, set, sizeof(*set));
971 
972 	/* Set up to return from userspace.  */
973 #ifdef CONFIG_MMU
974 	err |= __put_user(frame->retcode, &frame->pretcode);
975 #ifdef __mcoldfire__
976 	/* movel #__NR_rt_sigreturn,d0; trap #0 */
977 	err |= __put_user(0x203c0000, (long __user *)(frame->retcode + 0));
978 	err |= __put_user(0x00004e40 + (__NR_rt_sigreturn << 16),
979 			  (long __user *)(frame->retcode + 4));
980 #else
981 	/* moveq #,d0; notb d0; trap #0 */
982 	err |= __put_user(0x70004600 + ((__NR_rt_sigreturn ^ 0xff) << 16),
983 			  (long __user *)(frame->retcode + 0));
984 	err |= __put_user(0x4e40, (short __user *)(frame->retcode + 4));
985 #endif
986 #else
987 	err |= __put_user((void *) ret_from_user_rt_signal, &frame->pretcode);
988 #endif /* CONFIG_MMU */
989 
990 	if (err)
991 		goto give_sigsegv;
992 
993 	push_cache ((unsigned long) &frame->retcode);
994 
995 	/*
996 	 * Set up registers for signal handler.  All the state we are about
997 	 * to destroy is successfully copied to sigframe.
998 	 */
999 	wrusp ((unsigned long) frame);
1000 	regs->pc = (unsigned long) ka->sa.sa_handler;
1001 	adjustformat(regs);
1002 
1003 	/*
1004 	 * This is subtle; if we build more than one sigframe, all but the
1005 	 * first one will see frame format 0 and have fsize == 0, so we won't
1006 	 * screw stkadj.
1007 	 */
1008 	if (fsize)
1009 		regs->stkadj = fsize;
1010 
1011 	/* Prepare to skip over the extra stuff in the exception frame.  */
1012 	if (regs->stkadj) {
1013 		struct pt_regs *tregs =
1014 			(struct pt_regs *)((ulong)regs + regs->stkadj);
1015 #ifdef DEBUG
1016 		printk("Performing stackadjust=%04x\n", regs->stkadj);
1017 #endif
1018 		/* This must be copied with decreasing addresses to
1019                    handle overlaps.  */
1020 		tregs->vector = 0;
1021 		tregs->format = 0;
1022 		tregs->pc = regs->pc;
1023 		tregs->sr = regs->sr;
1024 	}
1025 	return 0;
1026 
1027 give_sigsegv:
1028 	force_sigsegv(sig, current);
1029 	return err;
1030 }
1031 
1032 static inline void
1033 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
1034 {
1035 	switch (regs->d0) {
1036 	case -ERESTARTNOHAND:
1037 		if (!has_handler)
1038 			goto do_restart;
1039 		regs->d0 = -EINTR;
1040 		break;
1041 
1042 	case -ERESTART_RESTARTBLOCK:
1043 		if (!has_handler) {
1044 			regs->d0 = __NR_restart_syscall;
1045 			regs->pc -= 2;
1046 			break;
1047 		}
1048 		regs->d0 = -EINTR;
1049 		break;
1050 
1051 	case -ERESTARTSYS:
1052 		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
1053 			regs->d0 = -EINTR;
1054 			break;
1055 		}
1056 	/* fallthrough */
1057 	case -ERESTARTNOINTR:
1058 	do_restart:
1059 		regs->d0 = regs->orig_d0;
1060 		regs->pc -= 2;
1061 		break;
1062 	}
1063 }
1064 
1065 /*
1066  * OK, we're invoking a handler
1067  */
1068 static void
1069 handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
1070 	      struct pt_regs *regs)
1071 {
1072 	sigset_t *oldset = sigmask_to_save();
1073 	int err;
1074 	/* are we from a system call? */
1075 	if (regs->orig_d0 >= 0)
1076 		/* If so, check system call restarting.. */
1077 		handle_restart(regs, ka, 1);
1078 
1079 	/* set up the stack frame */
1080 	if (ka->sa.sa_flags & SA_SIGINFO)
1081 		err = setup_rt_frame(sig, ka, info, oldset, regs);
1082 	else
1083 		err = setup_frame(sig, ka, oldset, regs);
1084 
1085 	if (err)
1086 		return;
1087 
1088 	signal_delivered(sig, info, ka, regs, 0);
1089 
1090 	if (test_thread_flag(TIF_DELAYED_TRACE)) {
1091 		regs->sr &= ~0x8000;
1092 		send_sig(SIGTRAP, current, 1);
1093 	}
1094 }
1095 
1096 /*
1097  * Note that 'init' is a special process: it doesn't get signals it doesn't
1098  * want to handle. Thus you cannot kill init even with a SIGKILL even by
1099  * mistake.
1100  */
1101 static void do_signal(struct pt_regs *regs)
1102 {
1103 	siginfo_t info;
1104 	struct k_sigaction ka;
1105 	int signr;
1106 
1107 	current->thread.esp0 = (unsigned long) regs;
1108 
1109 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
1110 	if (signr > 0) {
1111 		/* Whee!  Actually deliver the signal.  */
1112 		handle_signal(signr, &ka, &info, regs);
1113 		return;
1114 	}
1115 
1116 	/* Did we come from a system call? */
1117 	if (regs->orig_d0 >= 0)
1118 		/* Restart the system call - no handlers present */
1119 		handle_restart(regs, NULL, 0);
1120 
1121 	/* If there's no signal to deliver, we just restore the saved mask.  */
1122 	restore_saved_sigmask();
1123 }
1124 
1125 void do_notify_resume(struct pt_regs *regs)
1126 {
1127 	if (test_thread_flag(TIF_SIGPENDING))
1128 		do_signal(regs);
1129 
1130 	if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
1131 		tracehook_notify_resume(regs);
1132 }
1133