xref: /openbmc/linux/arch/m68k/kernel/signal.c (revision 6dfcd296)
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/extable.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 #include <asm/cacheflush.h>
54 
55 #ifdef CONFIG_MMU
56 
57 /*
58  * Handle the slight differences in classic 68k and ColdFire trap frames.
59  */
60 #ifdef CONFIG_COLDFIRE
61 #define	FORMAT		4
62 #define	FMT4SIZE	0
63 #else
64 #define	FORMAT		0
65 #define	FMT4SIZE	sizeof(((struct frame *)0)->un.fmt4)
66 #endif
67 
68 static const int frame_size_change[16] = {
69   [1]	= -1, /* sizeof(((struct frame *)0)->un.fmt1), */
70   [2]	= sizeof(((struct frame *)0)->un.fmt2),
71   [3]	= sizeof(((struct frame *)0)->un.fmt3),
72   [4]	= FMT4SIZE,
73   [5]	= -1, /* sizeof(((struct frame *)0)->un.fmt5), */
74   [6]	= -1, /* sizeof(((struct frame *)0)->un.fmt6), */
75   [7]	= sizeof(((struct frame *)0)->un.fmt7),
76   [8]	= -1, /* sizeof(((struct frame *)0)->un.fmt8), */
77   [9]	= sizeof(((struct frame *)0)->un.fmt9),
78   [10]	= sizeof(((struct frame *)0)->un.fmta),
79   [11]	= sizeof(((struct frame *)0)->un.fmtb),
80   [12]	= -1, /* sizeof(((struct frame *)0)->un.fmtc), */
81   [13]	= -1, /* sizeof(((struct frame *)0)->un.fmtd), */
82   [14]	= -1, /* sizeof(((struct frame *)0)->un.fmte), */
83   [15]	= -1, /* sizeof(((struct frame *)0)->un.fmtf), */
84 };
85 
86 static inline int frame_extra_sizes(int f)
87 {
88 	return frame_size_change[f];
89 }
90 
91 int handle_kernel_fault(struct pt_regs *regs)
92 {
93 	const struct exception_table_entry *fixup;
94 	struct pt_regs *tregs;
95 
96 	/* Are we prepared to handle this kernel fault? */
97 	fixup = search_exception_tables(regs->pc);
98 	if (!fixup)
99 		return 0;
100 
101 	/* Create a new four word stack frame, discarding the old one. */
102 	regs->stkadj = frame_extra_sizes(regs->format);
103 	tregs =	(struct pt_regs *)((long)regs + regs->stkadj);
104 	tregs->vector = regs->vector;
105 	tregs->format = FORMAT;
106 	tregs->pc = fixup->fixup;
107 	tregs->sr = regs->sr;
108 
109 	return 1;
110 }
111 
112 void ptrace_signal_deliver(void)
113 {
114 	struct pt_regs *regs = signal_pt_regs();
115 	if (regs->orig_d0 < 0)
116 		return;
117 	switch (regs->d0) {
118 	case -ERESTARTNOHAND:
119 	case -ERESTARTSYS:
120 	case -ERESTARTNOINTR:
121 		regs->d0 = regs->orig_d0;
122 		regs->orig_d0 = -1;
123 		regs->pc -= 2;
124 		break;
125 	}
126 }
127 
128 static inline void push_cache (unsigned long vaddr)
129 {
130 	/*
131 	 * Using the old cache_push_v() was really a big waste.
132 	 *
133 	 * What we are trying to do is to flush 8 bytes to ram.
134 	 * Flushing 2 cache lines of 16 bytes is much cheaper than
135 	 * flushing 1 or 2 pages, as previously done in
136 	 * cache_push_v().
137 	 *                                                     Jes
138 	 */
139 	if (CPU_IS_040) {
140 		unsigned long temp;
141 
142 		__asm__ __volatile__ (".chip 68040\n\t"
143 				      "nop\n\t"
144 				      "ptestr (%1)\n\t"
145 				      "movec %%mmusr,%0\n\t"
146 				      ".chip 68k"
147 				      : "=r" (temp)
148 				      : "a" (vaddr));
149 
150 		temp &= PAGE_MASK;
151 		temp |= vaddr & ~PAGE_MASK;
152 
153 		__asm__ __volatile__ (".chip 68040\n\t"
154 				      "nop\n\t"
155 				      "cpushl %%bc,(%0)\n\t"
156 				      ".chip 68k"
157 				      : : "a" (temp));
158 	}
159 	else if (CPU_IS_060) {
160 		unsigned long temp;
161 		__asm__ __volatile__ (".chip 68060\n\t"
162 				      "plpar (%0)\n\t"
163 				      ".chip 68k"
164 				      : "=a" (temp)
165 				      : "0" (vaddr));
166 		__asm__ __volatile__ (".chip 68060\n\t"
167 				      "cpushl %%bc,(%0)\n\t"
168 				      ".chip 68k"
169 				      : : "a" (temp));
170 	} else if (!CPU_IS_COLDFIRE) {
171 		/*
172 		 * 68030/68020 have no writeback cache;
173 		 * still need to clear icache.
174 		 * Note that vaddr is guaranteed to be long word aligned.
175 		 */
176 		unsigned long temp;
177 		asm volatile ("movec %%cacr,%0" : "=r" (temp));
178 		temp += 4;
179 		asm volatile ("movec %0,%%caar\n\t"
180 			      "movec %1,%%cacr"
181 			      : : "r" (vaddr), "r" (temp));
182 		asm volatile ("movec %0,%%caar\n\t"
183 			      "movec %1,%%cacr"
184 			      : : "r" (vaddr + 4), "r" (temp));
185 	} else {
186 		/* CPU_IS_COLDFIRE */
187 #if defined(CONFIG_CACHE_COPYBACK)
188 		flush_cf_dcache(0, DCACHE_MAX_ADDR);
189 #endif
190 		/* Invalidate instruction cache for the pushed bytes */
191 		clear_cf_icache(vaddr, vaddr + 8);
192 	}
193 }
194 
195 static inline void adjustformat(struct pt_regs *regs)
196 {
197 }
198 
199 static inline void save_a5_state(struct sigcontext *sc, struct pt_regs *regs)
200 {
201 }
202 
203 #else /* CONFIG_MMU */
204 
205 void ret_from_user_signal(void);
206 void ret_from_user_rt_signal(void);
207 
208 static inline int frame_extra_sizes(int f)
209 {
210 	/* No frame size adjustments required on non-MMU CPUs */
211 	return 0;
212 }
213 
214 static inline void adjustformat(struct pt_regs *regs)
215 {
216 	/*
217 	 * set format byte to make stack appear modulo 4, which it will
218 	 * be when doing the rte
219 	 */
220 	regs->format = 0x4;
221 }
222 
223 static inline void save_a5_state(struct sigcontext *sc, struct pt_regs *regs)
224 {
225 	sc->sc_a5 = ((struct switch_stack *)regs - 1)->a5;
226 }
227 
228 static inline void push_cache(unsigned long vaddr)
229 {
230 }
231 
232 #endif /* CONFIG_MMU */
233 
234 /*
235  * Do a signal return; undo the signal stack.
236  *
237  * Keep the return code on the stack quadword aligned!
238  * That makes the cache flush below easier.
239  */
240 
241 struct sigframe
242 {
243 	char __user *pretcode;
244 	int sig;
245 	int code;
246 	struct sigcontext __user *psc;
247 	char retcode[8];
248 	unsigned long extramask[_NSIG_WORDS-1];
249 	struct sigcontext sc;
250 };
251 
252 struct rt_sigframe
253 {
254 	char __user *pretcode;
255 	int sig;
256 	struct siginfo __user *pinfo;
257 	void __user *puc;
258 	char retcode[8];
259 	struct siginfo info;
260 	struct ucontext uc;
261 };
262 
263 #define FPCONTEXT_SIZE	216
264 #define uc_fpstate	uc_filler[0]
265 #define uc_formatvec	uc_filler[FPCONTEXT_SIZE/4]
266 #define uc_extra	uc_filler[FPCONTEXT_SIZE/4+1]
267 
268 #ifdef CONFIG_FPU
269 
270 static unsigned char fpu_version;	/* version number of fpu, set by setup_frame */
271 
272 static inline int restore_fpu_state(struct sigcontext *sc)
273 {
274 	int err = 1;
275 
276 	if (FPU_IS_EMU) {
277 	    /* restore registers */
278 	    memcpy(current->thread.fpcntl, sc->sc_fpcntl, 12);
279 	    memcpy(current->thread.fp, sc->sc_fpregs, 24);
280 	    return 0;
281 	}
282 
283 	if (CPU_IS_060 ? sc->sc_fpstate[2] : sc->sc_fpstate[0]) {
284 	    /* Verify the frame format.  */
285 	    if (!(CPU_IS_060 || CPU_IS_COLDFIRE) &&
286 		 (sc->sc_fpstate[0] != fpu_version))
287 		goto out;
288 	    if (CPU_IS_020_OR_030) {
289 		if (m68k_fputype & FPU_68881 &&
290 		    !(sc->sc_fpstate[1] == 0x18 || sc->sc_fpstate[1] == 0xb4))
291 		    goto out;
292 		if (m68k_fputype & FPU_68882 &&
293 		    !(sc->sc_fpstate[1] == 0x38 || sc->sc_fpstate[1] == 0xd4))
294 		    goto out;
295 	    } else if (CPU_IS_040) {
296 		if (!(sc->sc_fpstate[1] == 0x00 ||
297                       sc->sc_fpstate[1] == 0x28 ||
298                       sc->sc_fpstate[1] == 0x60))
299 		    goto out;
300 	    } else if (CPU_IS_060) {
301 		if (!(sc->sc_fpstate[3] == 0x00 ||
302                       sc->sc_fpstate[3] == 0x60 ||
303 		      sc->sc_fpstate[3] == 0xe0))
304 		    goto out;
305 	    } else if (CPU_IS_COLDFIRE) {
306 		if (!(sc->sc_fpstate[0] == 0x00 ||
307 		      sc->sc_fpstate[0] == 0x05 ||
308 		      sc->sc_fpstate[0] == 0xe5))
309 		    goto out;
310 	    } else
311 		goto out;
312 
313 	    if (CPU_IS_COLDFIRE) {
314 		__asm__ volatile ("fmovemd %0,%%fp0-%%fp1\n\t"
315 				  "fmovel %1,%%fpcr\n\t"
316 				  "fmovel %2,%%fpsr\n\t"
317 				  "fmovel %3,%%fpiar"
318 				  : /* no outputs */
319 				  : "m" (sc->sc_fpregs[0]),
320 				    "m" (sc->sc_fpcntl[0]),
321 				    "m" (sc->sc_fpcntl[1]),
322 				    "m" (sc->sc_fpcntl[2]));
323 	    } else {
324 		__asm__ volatile (".chip 68k/68881\n\t"
325 				  "fmovemx %0,%%fp0-%%fp1\n\t"
326 				  "fmoveml %1,%%fpcr/%%fpsr/%%fpiar\n\t"
327 				  ".chip 68k"
328 				  : /* no outputs */
329 				  : "m" (*sc->sc_fpregs),
330 				    "m" (*sc->sc_fpcntl));
331 	    }
332 	}
333 
334 	if (CPU_IS_COLDFIRE) {
335 		__asm__ volatile ("frestore %0" : : "m" (*sc->sc_fpstate));
336 	} else {
337 		__asm__ volatile (".chip 68k/68881\n\t"
338 				  "frestore %0\n\t"
339 				  ".chip 68k"
340 				  : : "m" (*sc->sc_fpstate));
341 	}
342 	err = 0;
343 
344 out:
345 	return err;
346 }
347 
348 static inline int rt_restore_fpu_state(struct ucontext __user *uc)
349 {
350 	unsigned char fpstate[FPCONTEXT_SIZE];
351 	int context_size = CPU_IS_060 ? 8 : (CPU_IS_COLDFIRE ? 12 : 0);
352 	fpregset_t fpregs;
353 	int err = 1;
354 
355 	if (FPU_IS_EMU) {
356 		/* restore fpu control register */
357 		if (__copy_from_user(current->thread.fpcntl,
358 				uc->uc_mcontext.fpregs.f_fpcntl, 12))
359 			goto out;
360 		/* restore all other fpu register */
361 		if (__copy_from_user(current->thread.fp,
362 				uc->uc_mcontext.fpregs.f_fpregs, 96))
363 			goto out;
364 		return 0;
365 	}
366 
367 	if (__get_user(*(long *)fpstate, (long __user *)&uc->uc_fpstate))
368 		goto out;
369 	if (CPU_IS_060 ? fpstate[2] : fpstate[0]) {
370 		if (!(CPU_IS_060 || CPU_IS_COLDFIRE))
371 			context_size = fpstate[1];
372 		/* Verify the frame format.  */
373 		if (!(CPU_IS_060 || CPU_IS_COLDFIRE) &&
374 		     (fpstate[0] != fpu_version))
375 			goto out;
376 		if (CPU_IS_020_OR_030) {
377 			if (m68k_fputype & FPU_68881 &&
378 			    !(context_size == 0x18 || context_size == 0xb4))
379 				goto out;
380 			if (m68k_fputype & FPU_68882 &&
381 			    !(context_size == 0x38 || context_size == 0xd4))
382 				goto out;
383 		} else if (CPU_IS_040) {
384 			if (!(context_size == 0x00 ||
385 			      context_size == 0x28 ||
386 			      context_size == 0x60))
387 				goto out;
388 		} else if (CPU_IS_060) {
389 			if (!(fpstate[3] == 0x00 ||
390 			      fpstate[3] == 0x60 ||
391 			      fpstate[3] == 0xe0))
392 				goto out;
393 		} else if (CPU_IS_COLDFIRE) {
394 			if (!(fpstate[3] == 0x00 ||
395 			      fpstate[3] == 0x05 ||
396 			      fpstate[3] == 0xe5))
397 				goto out;
398 		} else
399 			goto out;
400 		if (__copy_from_user(&fpregs, &uc->uc_mcontext.fpregs,
401 				     sizeof(fpregs)))
402 			goto out;
403 
404 		if (CPU_IS_COLDFIRE) {
405 			__asm__ volatile ("fmovemd %0,%%fp0-%%fp7\n\t"
406 					  "fmovel %1,%%fpcr\n\t"
407 					  "fmovel %2,%%fpsr\n\t"
408 					  "fmovel %3,%%fpiar"
409 					  : /* no outputs */
410 					  : "m" (fpregs.f_fpregs[0]),
411 					    "m" (fpregs.f_fpcntl[0]),
412 					    "m" (fpregs.f_fpcntl[1]),
413 					    "m" (fpregs.f_fpcntl[2]));
414 		} else {
415 			__asm__ volatile (".chip 68k/68881\n\t"
416 					  "fmovemx %0,%%fp0-%%fp7\n\t"
417 					  "fmoveml %1,%%fpcr/%%fpsr/%%fpiar\n\t"
418 					  ".chip 68k"
419 					  : /* no outputs */
420 					  : "m" (*fpregs.f_fpregs),
421 					    "m" (*fpregs.f_fpcntl));
422 		}
423 	}
424 	if (context_size &&
425 	    __copy_from_user(fpstate + 4, (long __user *)&uc->uc_fpstate + 1,
426 			     context_size))
427 		goto out;
428 
429 	if (CPU_IS_COLDFIRE) {
430 		__asm__ volatile ("frestore %0" : : "m" (*fpstate));
431 	} else {
432 		__asm__ volatile (".chip 68k/68881\n\t"
433 				  "frestore %0\n\t"
434 				  ".chip 68k"
435 				  : : "m" (*fpstate));
436 	}
437 	err = 0;
438 
439 out:
440 	return err;
441 }
442 
443 /*
444  * Set up a signal frame.
445  */
446 static inline void save_fpu_state(struct sigcontext *sc, struct pt_regs *regs)
447 {
448 	if (FPU_IS_EMU) {
449 		/* save registers */
450 		memcpy(sc->sc_fpcntl, current->thread.fpcntl, 12);
451 		memcpy(sc->sc_fpregs, current->thread.fp, 24);
452 		return;
453 	}
454 
455 	if (CPU_IS_COLDFIRE) {
456 		__asm__ volatile ("fsave %0"
457 				  : : "m" (*sc->sc_fpstate) : "memory");
458 	} else {
459 		__asm__ volatile (".chip 68k/68881\n\t"
460 				  "fsave %0\n\t"
461 				  ".chip 68k"
462 				  : : "m" (*sc->sc_fpstate) : "memory");
463 	}
464 
465 	if (CPU_IS_060 ? sc->sc_fpstate[2] : sc->sc_fpstate[0]) {
466 		fpu_version = sc->sc_fpstate[0];
467 		if (CPU_IS_020_OR_030 &&
468 		    regs->vector >= (VEC_FPBRUC * 4) &&
469 		    regs->vector <= (VEC_FPNAN * 4)) {
470 			/* Clear pending exception in 68882 idle frame */
471 			if (*(unsigned short *) sc->sc_fpstate == 0x1f38)
472 				sc->sc_fpstate[0x38] |= 1 << 3;
473 		}
474 
475 		if (CPU_IS_COLDFIRE) {
476 			__asm__ volatile ("fmovemd %%fp0-%%fp1,%0\n\t"
477 					  "fmovel %%fpcr,%1\n\t"
478 					  "fmovel %%fpsr,%2\n\t"
479 					  "fmovel %%fpiar,%3"
480 					  : "=m" (sc->sc_fpregs[0]),
481 					    "=m" (sc->sc_fpcntl[0]),
482 					    "=m" (sc->sc_fpcntl[1]),
483 					    "=m" (sc->sc_fpcntl[2])
484 					  : /* no inputs */
485 					  : "memory");
486 		} else {
487 			__asm__ volatile (".chip 68k/68881\n\t"
488 					  "fmovemx %%fp0-%%fp1,%0\n\t"
489 					  "fmoveml %%fpcr/%%fpsr/%%fpiar,%1\n\t"
490 					  ".chip 68k"
491 					  : "=m" (*sc->sc_fpregs),
492 					    "=m" (*sc->sc_fpcntl)
493 					  : /* no inputs */
494 					  : "memory");
495 		}
496 	}
497 }
498 
499 static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs *regs)
500 {
501 	unsigned char fpstate[FPCONTEXT_SIZE];
502 	int context_size = CPU_IS_060 ? 8 : (CPU_IS_COLDFIRE ? 12 : 0);
503 	int err = 0;
504 
505 	if (FPU_IS_EMU) {
506 		/* save fpu control register */
507 		err |= copy_to_user(uc->uc_mcontext.fpregs.f_fpcntl,
508 				current->thread.fpcntl, 12);
509 		/* save all other fpu register */
510 		err |= copy_to_user(uc->uc_mcontext.fpregs.f_fpregs,
511 				current->thread.fp, 96);
512 		return err;
513 	}
514 
515 	if (CPU_IS_COLDFIRE) {
516 		__asm__ volatile ("fsave %0" : : "m" (*fpstate) : "memory");
517 	} else {
518 		__asm__ volatile (".chip 68k/68881\n\t"
519 				  "fsave %0\n\t"
520 				  ".chip 68k"
521 				  : : "m" (*fpstate) : "memory");
522 	}
523 
524 	err |= __put_user(*(long *)fpstate, (long __user *)&uc->uc_fpstate);
525 	if (CPU_IS_060 ? fpstate[2] : fpstate[0]) {
526 		fpregset_t fpregs;
527 		if (!(CPU_IS_060 || CPU_IS_COLDFIRE))
528 			context_size = fpstate[1];
529 		fpu_version = fpstate[0];
530 		if (CPU_IS_020_OR_030 &&
531 		    regs->vector >= (VEC_FPBRUC * 4) &&
532 		    regs->vector <= (VEC_FPNAN * 4)) {
533 			/* Clear pending exception in 68882 idle frame */
534 			if (*(unsigned short *) fpstate == 0x1f38)
535 				fpstate[0x38] |= 1 << 3;
536 		}
537 		if (CPU_IS_COLDFIRE) {
538 			__asm__ volatile ("fmovemd %%fp0-%%fp7,%0\n\t"
539 					  "fmovel %%fpcr,%1\n\t"
540 					  "fmovel %%fpsr,%2\n\t"
541 					  "fmovel %%fpiar,%3"
542 					  : "=m" (fpregs.f_fpregs[0]),
543 					    "=m" (fpregs.f_fpcntl[0]),
544 					    "=m" (fpregs.f_fpcntl[1]),
545 					    "=m" (fpregs.f_fpcntl[2])
546 					  : /* no inputs */
547 					  : "memory");
548 		} else {
549 			__asm__ volatile (".chip 68k/68881\n\t"
550 					  "fmovemx %%fp0-%%fp7,%0\n\t"
551 					  "fmoveml %%fpcr/%%fpsr/%%fpiar,%1\n\t"
552 					  ".chip 68k"
553 					  : "=m" (*fpregs.f_fpregs),
554 					    "=m" (*fpregs.f_fpcntl)
555 					  : /* no inputs */
556 					  : "memory");
557 		}
558 		err |= copy_to_user(&uc->uc_mcontext.fpregs, &fpregs,
559 				    sizeof(fpregs));
560 	}
561 	if (context_size)
562 		err |= copy_to_user((long __user *)&uc->uc_fpstate + 1, fpstate + 4,
563 				    context_size);
564 	return err;
565 }
566 
567 #else /* CONFIG_FPU */
568 
569 /*
570  * For the case with no FPU configured these all do nothing.
571  */
572 static inline int restore_fpu_state(struct sigcontext *sc)
573 {
574 	return 0;
575 }
576 
577 static inline int rt_restore_fpu_state(struct ucontext __user *uc)
578 {
579 	return 0;
580 }
581 
582 static inline void save_fpu_state(struct sigcontext *sc, struct pt_regs *regs)
583 {
584 }
585 
586 static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs *regs)
587 {
588 	return 0;
589 }
590 
591 #endif /* CONFIG_FPU */
592 
593 static int mangle_kernel_stack(struct pt_regs *regs, int formatvec,
594 			       void __user *fp)
595 {
596 	int fsize = frame_extra_sizes(formatvec >> 12);
597 	if (fsize < 0) {
598 		/*
599 		 * user process trying to return with weird frame format
600 		 */
601 #ifdef DEBUG
602 		printk("user process returning with weird frame format\n");
603 #endif
604 		return 1;
605 	}
606 	if (!fsize) {
607 		regs->format = formatvec >> 12;
608 		regs->vector = formatvec & 0xfff;
609 	} else {
610 		struct switch_stack *sw = (struct switch_stack *)regs - 1;
611 		unsigned long buf[fsize / 2]; /* yes, twice as much */
612 
613 		/* that'll make sure that expansion won't crap over data */
614 		if (copy_from_user(buf + fsize / 4, fp, fsize))
615 			return 1;
616 
617 		/* point of no return */
618 		regs->format = formatvec >> 12;
619 		regs->vector = formatvec & 0xfff;
620 #define frame_offset (sizeof(struct pt_regs)+sizeof(struct switch_stack))
621 		__asm__ __volatile__ (
622 #ifdef CONFIG_COLDFIRE
623 			 "   movel %0,%/sp\n\t"
624 			 "   bra ret_from_signal\n"
625 #else
626 			 "   movel %0,%/a0\n\t"
627 			 "   subl %1,%/a0\n\t"     /* make room on stack */
628 			 "   movel %/a0,%/sp\n\t"  /* set stack pointer */
629 			 /* move switch_stack and pt_regs */
630 			 "1: movel %0@+,%/a0@+\n\t"
631 			 "   dbra %2,1b\n\t"
632 			 "   lea %/sp@(%c3),%/a0\n\t" /* add offset of fmt */
633 			 "   lsrl  #2,%1\n\t"
634 			 "   subql #1,%1\n\t"
635 			 /* copy to the gap we'd made */
636 			 "2: movel %4@+,%/a0@+\n\t"
637 			 "   dbra %1,2b\n\t"
638 			 "   bral ret_from_signal\n"
639 #endif
640 			 : /* no outputs, it doesn't ever return */
641 			 : "a" (sw), "d" (fsize), "d" (frame_offset/4-1),
642 			   "n" (frame_offset), "a" (buf + fsize/4)
643 			 : "a0");
644 #undef frame_offset
645 	}
646 	return 0;
647 }
648 
649 static inline int
650 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __user *fp)
651 {
652 	int formatvec;
653 	struct sigcontext context;
654 	int err = 0;
655 
656 	/* Always make any pending restarted system calls return -EINTR */
657 	current->restart_block.fn = do_no_restart_syscall;
658 
659 	/* get previous context */
660 	if (copy_from_user(&context, usc, sizeof(context)))
661 		goto badframe;
662 
663 	/* restore passed registers */
664 	regs->d0 = context.sc_d0;
665 	regs->d1 = context.sc_d1;
666 	regs->a0 = context.sc_a0;
667 	regs->a1 = context.sc_a1;
668 	regs->sr = (regs->sr & 0xff00) | (context.sc_sr & 0xff);
669 	regs->pc = context.sc_pc;
670 	regs->orig_d0 = -1;		/* disable syscall checks */
671 	wrusp(context.sc_usp);
672 	formatvec = context.sc_formatvec;
673 
674 	err = restore_fpu_state(&context);
675 
676 	if (err || mangle_kernel_stack(regs, formatvec, fp))
677 		goto badframe;
678 
679 	return 0;
680 
681 badframe:
682 	return 1;
683 }
684 
685 static inline int
686 rt_restore_ucontext(struct pt_regs *regs, struct switch_stack *sw,
687 		    struct ucontext __user *uc)
688 {
689 	int temp;
690 	greg_t __user *gregs = uc->uc_mcontext.gregs;
691 	unsigned long usp;
692 	int err;
693 
694 	/* Always make any pending restarted system calls return -EINTR */
695 	current->restart_block.fn = do_no_restart_syscall;
696 
697 	err = __get_user(temp, &uc->uc_mcontext.version);
698 	if (temp != MCONTEXT_VERSION)
699 		goto badframe;
700 	/* restore passed registers */
701 	err |= __get_user(regs->d0, &gregs[0]);
702 	err |= __get_user(regs->d1, &gregs[1]);
703 	err |= __get_user(regs->d2, &gregs[2]);
704 	err |= __get_user(regs->d3, &gregs[3]);
705 	err |= __get_user(regs->d4, &gregs[4]);
706 	err |= __get_user(regs->d5, &gregs[5]);
707 	err |= __get_user(sw->d6, &gregs[6]);
708 	err |= __get_user(sw->d7, &gregs[7]);
709 	err |= __get_user(regs->a0, &gregs[8]);
710 	err |= __get_user(regs->a1, &gregs[9]);
711 	err |= __get_user(regs->a2, &gregs[10]);
712 	err |= __get_user(sw->a3, &gregs[11]);
713 	err |= __get_user(sw->a4, &gregs[12]);
714 	err |= __get_user(sw->a5, &gregs[13]);
715 	err |= __get_user(sw->a6, &gregs[14]);
716 	err |= __get_user(usp, &gregs[15]);
717 	wrusp(usp);
718 	err |= __get_user(regs->pc, &gregs[16]);
719 	err |= __get_user(temp, &gregs[17]);
720 	regs->sr = (regs->sr & 0xff00) | (temp & 0xff);
721 	regs->orig_d0 = -1;		/* disable syscall checks */
722 	err |= __get_user(temp, &uc->uc_formatvec);
723 
724 	err |= rt_restore_fpu_state(uc);
725 	err |= restore_altstack(&uc->uc_stack);
726 
727 	if (err)
728 		goto badframe;
729 
730 	if (mangle_kernel_stack(regs, temp, &uc->uc_extra))
731 		goto badframe;
732 
733 	return 0;
734 
735 badframe:
736 	return 1;
737 }
738 
739 asmlinkage int do_sigreturn(struct pt_regs *regs, struct switch_stack *sw)
740 {
741 	unsigned long usp = rdusp();
742 	struct sigframe __user *frame = (struct sigframe __user *)(usp - 4);
743 	sigset_t set;
744 
745 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
746 		goto badframe;
747 	if (__get_user(set.sig[0], &frame->sc.sc_mask) ||
748 	    (_NSIG_WORDS > 1 &&
749 	     __copy_from_user(&set.sig[1], &frame->extramask,
750 			      sizeof(frame->extramask))))
751 		goto badframe;
752 
753 	set_current_blocked(&set);
754 
755 	if (restore_sigcontext(regs, &frame->sc, frame + 1))
756 		goto badframe;
757 	return regs->d0;
758 
759 badframe:
760 	force_sig(SIGSEGV, current);
761 	return 0;
762 }
763 
764 asmlinkage int do_rt_sigreturn(struct pt_regs *regs, struct switch_stack *sw)
765 {
766 	unsigned long usp = rdusp();
767 	struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(usp - 4);
768 	sigset_t set;
769 
770 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
771 		goto badframe;
772 	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
773 		goto badframe;
774 
775 	set_current_blocked(&set);
776 
777 	if (rt_restore_ucontext(regs, sw, &frame->uc))
778 		goto badframe;
779 	return regs->d0;
780 
781 badframe:
782 	force_sig(SIGSEGV, current);
783 	return 0;
784 }
785 
786 static void setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
787 			     unsigned long mask)
788 {
789 	sc->sc_mask = mask;
790 	sc->sc_usp = rdusp();
791 	sc->sc_d0 = regs->d0;
792 	sc->sc_d1 = regs->d1;
793 	sc->sc_a0 = regs->a0;
794 	sc->sc_a1 = regs->a1;
795 	sc->sc_sr = regs->sr;
796 	sc->sc_pc = regs->pc;
797 	sc->sc_formatvec = regs->format << 12 | regs->vector;
798 	save_a5_state(sc, regs);
799 	save_fpu_state(sc, regs);
800 }
801 
802 static inline int rt_setup_ucontext(struct ucontext __user *uc, struct pt_regs *regs)
803 {
804 	struct switch_stack *sw = (struct switch_stack *)regs - 1;
805 	greg_t __user *gregs = uc->uc_mcontext.gregs;
806 	int err = 0;
807 
808 	err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
809 	err |= __put_user(regs->d0, &gregs[0]);
810 	err |= __put_user(regs->d1, &gregs[1]);
811 	err |= __put_user(regs->d2, &gregs[2]);
812 	err |= __put_user(regs->d3, &gregs[3]);
813 	err |= __put_user(regs->d4, &gregs[4]);
814 	err |= __put_user(regs->d5, &gregs[5]);
815 	err |= __put_user(sw->d6, &gregs[6]);
816 	err |= __put_user(sw->d7, &gregs[7]);
817 	err |= __put_user(regs->a0, &gregs[8]);
818 	err |= __put_user(regs->a1, &gregs[9]);
819 	err |= __put_user(regs->a2, &gregs[10]);
820 	err |= __put_user(sw->a3, &gregs[11]);
821 	err |= __put_user(sw->a4, &gregs[12]);
822 	err |= __put_user(sw->a5, &gregs[13]);
823 	err |= __put_user(sw->a6, &gregs[14]);
824 	err |= __put_user(rdusp(), &gregs[15]);
825 	err |= __put_user(regs->pc, &gregs[16]);
826 	err |= __put_user(regs->sr, &gregs[17]);
827 	err |= __put_user((regs->format << 12) | regs->vector, &uc->uc_formatvec);
828 	err |= rt_save_fpu_state(uc, regs);
829 	return err;
830 }
831 
832 static inline void __user *
833 get_sigframe(struct ksignal *ksig, size_t frame_size)
834 {
835 	unsigned long usp = sigsp(rdusp(), ksig);
836 
837 	return (void __user *)((usp - frame_size) & -8UL);
838 }
839 
840 static int setup_frame(struct ksignal *ksig, sigset_t *set,
841 			struct pt_regs *regs)
842 {
843 	struct sigframe __user *frame;
844 	int fsize = frame_extra_sizes(regs->format);
845 	struct sigcontext context;
846 	int err = 0, sig = ksig->sig;
847 
848 	if (fsize < 0) {
849 #ifdef DEBUG
850 		printk ("setup_frame: Unknown frame format %#x\n",
851 			regs->format);
852 #endif
853 		return -EFAULT;
854 	}
855 
856 	frame = get_sigframe(ksig, sizeof(*frame) + fsize);
857 
858 	if (fsize)
859 		err |= copy_to_user (frame + 1, regs + 1, fsize);
860 
861 	err |= __put_user(sig, &frame->sig);
862 
863 	err |= __put_user(regs->vector, &frame->code);
864 	err |= __put_user(&frame->sc, &frame->psc);
865 
866 	if (_NSIG_WORDS > 1)
867 		err |= copy_to_user(frame->extramask, &set->sig[1],
868 				    sizeof(frame->extramask));
869 
870 	setup_sigcontext(&context, regs, set->sig[0]);
871 	err |= copy_to_user (&frame->sc, &context, sizeof(context));
872 
873 	/* Set up to return from userspace.  */
874 #ifdef CONFIG_MMU
875 	err |= __put_user(frame->retcode, &frame->pretcode);
876 	/* moveq #,d0; trap #0 */
877 	err |= __put_user(0x70004e40 + (__NR_sigreturn << 16),
878 			  (long __user *)(frame->retcode));
879 #else
880 	err |= __put_user((void *) ret_from_user_signal, &frame->pretcode);
881 #endif
882 
883 	if (err)
884 		return -EFAULT;
885 
886 	push_cache ((unsigned long) &frame->retcode);
887 
888 	/*
889 	 * Set up registers for signal handler.  All the state we are about
890 	 * to destroy is successfully copied to sigframe.
891 	 */
892 	wrusp ((unsigned long) frame);
893 	regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
894 	adjustformat(regs);
895 
896 	/*
897 	 * This is subtle; if we build more than one sigframe, all but the
898 	 * first one will see frame format 0 and have fsize == 0, so we won't
899 	 * screw stkadj.
900 	 */
901 	if (fsize)
902 		regs->stkadj = fsize;
903 
904 	/* Prepare to skip over the extra stuff in the exception frame.  */
905 	if (regs->stkadj) {
906 		struct pt_regs *tregs =
907 			(struct pt_regs *)((ulong)regs + regs->stkadj);
908 #ifdef DEBUG
909 		printk("Performing stackadjust=%04x\n", regs->stkadj);
910 #endif
911 		/* This must be copied with decreasing addresses to
912                    handle overlaps.  */
913 		tregs->vector = 0;
914 		tregs->format = 0;
915 		tregs->pc = regs->pc;
916 		tregs->sr = regs->sr;
917 	}
918 	return 0;
919 }
920 
921 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
922 			   struct pt_regs *regs)
923 {
924 	struct rt_sigframe __user *frame;
925 	int fsize = frame_extra_sizes(regs->format);
926 	int err = 0, sig = ksig->sig;
927 
928 	if (fsize < 0) {
929 #ifdef DEBUG
930 		printk ("setup_frame: Unknown frame format %#x\n",
931 			regs->format);
932 #endif
933 		return -EFAULT;
934 	}
935 
936 	frame = get_sigframe(ksig, sizeof(*frame));
937 
938 	if (fsize)
939 		err |= copy_to_user (&frame->uc.uc_extra, regs + 1, fsize);
940 
941 	err |= __put_user(sig, &frame->sig);
942 	err |= __put_user(&frame->info, &frame->pinfo);
943 	err |= __put_user(&frame->uc, &frame->puc);
944 	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
945 
946 	/* Create the ucontext.  */
947 	err |= __put_user(0, &frame->uc.uc_flags);
948 	err |= __put_user(NULL, &frame->uc.uc_link);
949 	err |= __save_altstack(&frame->uc.uc_stack, rdusp());
950 	err |= rt_setup_ucontext(&frame->uc, regs);
951 	err |= copy_to_user (&frame->uc.uc_sigmask, set, sizeof(*set));
952 
953 	/* Set up to return from userspace.  */
954 #ifdef CONFIG_MMU
955 	err |= __put_user(frame->retcode, &frame->pretcode);
956 #ifdef __mcoldfire__
957 	/* movel #__NR_rt_sigreturn,d0; trap #0 */
958 	err |= __put_user(0x203c0000, (long __user *)(frame->retcode + 0));
959 	err |= __put_user(0x00004e40 + (__NR_rt_sigreturn << 16),
960 			  (long __user *)(frame->retcode + 4));
961 #else
962 	/* moveq #,d0; notb d0; trap #0 */
963 	err |= __put_user(0x70004600 + ((__NR_rt_sigreturn ^ 0xff) << 16),
964 			  (long __user *)(frame->retcode + 0));
965 	err |= __put_user(0x4e40, (short __user *)(frame->retcode + 4));
966 #endif
967 #else
968 	err |= __put_user((void *) ret_from_user_rt_signal, &frame->pretcode);
969 #endif /* CONFIG_MMU */
970 
971 	if (err)
972 		return -EFAULT;
973 
974 	push_cache ((unsigned long) &frame->retcode);
975 
976 	/*
977 	 * Set up registers for signal handler.  All the state we are about
978 	 * to destroy is successfully copied to sigframe.
979 	 */
980 	wrusp ((unsigned long) frame);
981 	regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
982 	adjustformat(regs);
983 
984 	/*
985 	 * This is subtle; if we build more than one sigframe, all but the
986 	 * first one will see frame format 0 and have fsize == 0, so we won't
987 	 * screw stkadj.
988 	 */
989 	if (fsize)
990 		regs->stkadj = fsize;
991 
992 	/* Prepare to skip over the extra stuff in the exception frame.  */
993 	if (regs->stkadj) {
994 		struct pt_regs *tregs =
995 			(struct pt_regs *)((ulong)regs + regs->stkadj);
996 #ifdef DEBUG
997 		printk("Performing stackadjust=%04x\n", regs->stkadj);
998 #endif
999 		/* This must be copied with decreasing addresses to
1000                    handle overlaps.  */
1001 		tregs->vector = 0;
1002 		tregs->format = 0;
1003 		tregs->pc = regs->pc;
1004 		tregs->sr = regs->sr;
1005 	}
1006 	return 0;
1007 }
1008 
1009 static inline void
1010 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
1011 {
1012 	switch (regs->d0) {
1013 	case -ERESTARTNOHAND:
1014 		if (!has_handler)
1015 			goto do_restart;
1016 		regs->d0 = -EINTR;
1017 		break;
1018 
1019 	case -ERESTART_RESTARTBLOCK:
1020 		if (!has_handler) {
1021 			regs->d0 = __NR_restart_syscall;
1022 			regs->pc -= 2;
1023 			break;
1024 		}
1025 		regs->d0 = -EINTR;
1026 		break;
1027 
1028 	case -ERESTARTSYS:
1029 		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
1030 			regs->d0 = -EINTR;
1031 			break;
1032 		}
1033 	/* fallthrough */
1034 	case -ERESTARTNOINTR:
1035 	do_restart:
1036 		regs->d0 = regs->orig_d0;
1037 		regs->pc -= 2;
1038 		break;
1039 	}
1040 }
1041 
1042 /*
1043  * OK, we're invoking a handler
1044  */
1045 static void
1046 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
1047 {
1048 	sigset_t *oldset = sigmask_to_save();
1049 	int err;
1050 	/* are we from a system call? */
1051 	if (regs->orig_d0 >= 0)
1052 		/* If so, check system call restarting.. */
1053 		handle_restart(regs, &ksig->ka, 1);
1054 
1055 	/* set up the stack frame */
1056 	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
1057 		err = setup_rt_frame(ksig, oldset, regs);
1058 	else
1059 		err = setup_frame(ksig, oldset, regs);
1060 
1061 	signal_setup_done(err, ksig, 0);
1062 
1063 	if (test_thread_flag(TIF_DELAYED_TRACE)) {
1064 		regs->sr &= ~0x8000;
1065 		send_sig(SIGTRAP, current, 1);
1066 	}
1067 }
1068 
1069 /*
1070  * Note that 'init' is a special process: it doesn't get signals it doesn't
1071  * want to handle. Thus you cannot kill init even with a SIGKILL even by
1072  * mistake.
1073  */
1074 static void do_signal(struct pt_regs *regs)
1075 {
1076 	struct ksignal ksig;
1077 
1078 	current->thread.esp0 = (unsigned long) regs;
1079 
1080 	if (get_signal(&ksig)) {
1081 		/* Whee!  Actually deliver the signal.  */
1082 		handle_signal(&ksig, regs);
1083 		return;
1084 	}
1085 
1086 	/* Did we come from a system call? */
1087 	if (regs->orig_d0 >= 0)
1088 		/* Restart the system call - no handlers present */
1089 		handle_restart(regs, NULL, 0);
1090 
1091 	/* If there's no signal to deliver, we just restore the saved mask.  */
1092 	restore_saved_sigmask();
1093 }
1094 
1095 void do_notify_resume(struct pt_regs *regs)
1096 {
1097 	if (test_thread_flag(TIF_SIGPENDING))
1098 		do_signal(regs);
1099 
1100 	if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
1101 		tracehook_notify_resume(regs);
1102 }
1103