xref: /linux/arch/m68k/kernel/traps.c (revision 68550cbc6129159b7a6434796b721e8b66ee12f6)
1 /*
2  *  linux/arch/m68k/kernel/traps.c
3  *
4  *  Copyright (C) 1993, 1994 by Hamish Macdonald
5  *
6  *  68040 fixes by Michael Rausch
7  *  68040 fixes by Martin Apel
8  *  68040 fixes and writeback by Richard Zidlicky
9  *  68060 fixes by Roman Hodek
10  *  68060 fixes by Jesper Skov
11  *
12  * This file is subject to the terms and conditions of the GNU General Public
13  * License.  See the file COPYING in the main directory of this archive
14  * for more details.
15  */
16 
17 /*
18  * Sets up all exception vectors
19  */
20 
21 #include <linux/sched.h>
22 #include <linux/sched/debug.h>
23 #include <linux/signal.h>
24 #include <linux/kernel.h>
25 #include <linux/mm.h>
26 #include <linux/module.h>
27 #include <linux/user.h>
28 #include <linux/string.h>
29 #include <linux/linkage.h>
30 #include <linux/init.h>
31 #include <linux/ptrace.h>
32 #include <linux/kallsyms.h>
33 
34 #include <asm/setup.h>
35 #include <asm/fpu.h>
36 #include <linux/uaccess.h>
37 #include <asm/traps.h>
38 #include <asm/machdep.h>
39 #include <asm/siginfo.h>
40 #include <asm/tlbflush.h>
41 
42 static const char *vec_names[] = {
43 	[VEC_RESETSP]	= "RESET SP",
44 	[VEC_RESETPC]	= "RESET PC",
45 	[VEC_BUSERR]	= "BUS ERROR",
46 	[VEC_ADDRERR]	= "ADDRESS ERROR",
47 	[VEC_ILLEGAL]	= "ILLEGAL INSTRUCTION",
48 	[VEC_ZERODIV]	= "ZERO DIVIDE",
49 	[VEC_CHK]	= "CHK",
50 	[VEC_TRAP]	= "TRAPcc",
51 	[VEC_PRIV]	= "PRIVILEGE VIOLATION",
52 	[VEC_TRACE]	= "TRACE",
53 	[VEC_LINE10]	= "LINE 1010",
54 	[VEC_LINE11]	= "LINE 1111",
55 	[VEC_RESV12]	= "UNASSIGNED RESERVED 12",
56 	[VEC_COPROC]	= "COPROCESSOR PROTOCOL VIOLATION",
57 	[VEC_FORMAT]	= "FORMAT ERROR",
58 	[VEC_UNINT]	= "UNINITIALIZED INTERRUPT",
59 	[VEC_RESV16]	= "UNASSIGNED RESERVED 16",
60 	[VEC_RESV17]	= "UNASSIGNED RESERVED 17",
61 	[VEC_RESV18]	= "UNASSIGNED RESERVED 18",
62 	[VEC_RESV19]	= "UNASSIGNED RESERVED 19",
63 	[VEC_RESV20]	= "UNASSIGNED RESERVED 20",
64 	[VEC_RESV21]	= "UNASSIGNED RESERVED 21",
65 	[VEC_RESV22]	= "UNASSIGNED RESERVED 22",
66 	[VEC_RESV23]	= "UNASSIGNED RESERVED 23",
67 	[VEC_SPUR]	= "SPURIOUS INTERRUPT",
68 	[VEC_INT1]	= "LEVEL 1 INT",
69 	[VEC_INT2]	= "LEVEL 2 INT",
70 	[VEC_INT3]	= "LEVEL 3 INT",
71 	[VEC_INT4]	= "LEVEL 4 INT",
72 	[VEC_INT5]	= "LEVEL 5 INT",
73 	[VEC_INT6]	= "LEVEL 6 INT",
74 	[VEC_INT7]	= "LEVEL 7 INT",
75 	[VEC_SYS]	= "SYSCALL",
76 	[VEC_TRAP1]	= "TRAP #1",
77 	[VEC_TRAP2]	= "TRAP #2",
78 	[VEC_TRAP3]	= "TRAP #3",
79 	[VEC_TRAP4]	= "TRAP #4",
80 	[VEC_TRAP5]	= "TRAP #5",
81 	[VEC_TRAP6]	= "TRAP #6",
82 	[VEC_TRAP7]	= "TRAP #7",
83 	[VEC_TRAP8]	= "TRAP #8",
84 	[VEC_TRAP9]	= "TRAP #9",
85 	[VEC_TRAP10]	= "TRAP #10",
86 	[VEC_TRAP11]	= "TRAP #11",
87 	[VEC_TRAP12]	= "TRAP #12",
88 	[VEC_TRAP13]	= "TRAP #13",
89 	[VEC_TRAP14]	= "TRAP #14",
90 	[VEC_TRAP15]	= "TRAP #15",
91 	[VEC_FPBRUC]	= "FPCP BSUN",
92 	[VEC_FPIR]	= "FPCP INEXACT",
93 	[VEC_FPDIVZ]	= "FPCP DIV BY 0",
94 	[VEC_FPUNDER]	= "FPCP UNDERFLOW",
95 	[VEC_FPOE]	= "FPCP OPERAND ERROR",
96 	[VEC_FPOVER]	= "FPCP OVERFLOW",
97 	[VEC_FPNAN]	= "FPCP SNAN",
98 	[VEC_FPUNSUP]	= "FPCP UNSUPPORTED OPERATION",
99 	[VEC_MMUCFG]	= "MMU CONFIGURATION ERROR",
100 	[VEC_MMUILL]	= "MMU ILLEGAL OPERATION ERROR",
101 	[VEC_MMUACC]	= "MMU ACCESS LEVEL VIOLATION ERROR",
102 	[VEC_RESV59]	= "UNASSIGNED RESERVED 59",
103 	[VEC_UNIMPEA]	= "UNASSIGNED RESERVED 60",
104 	[VEC_UNIMPII]	= "UNASSIGNED RESERVED 61",
105 	[VEC_RESV62]	= "UNASSIGNED RESERVED 62",
106 	[VEC_RESV63]	= "UNASSIGNED RESERVED 63",
107 };
108 
109 static const char *space_names[] = {
110 	[0]		= "Space 0",
111 	[USER_DATA]	= "User Data",
112 	[USER_PROGRAM]	= "User Program",
113 #ifndef CONFIG_SUN3
114 	[3]		= "Space 3",
115 #else
116 	[FC_CONTROL]	= "Control",
117 #endif
118 	[4]		= "Space 4",
119 	[SUPER_DATA]	= "Super Data",
120 	[SUPER_PROGRAM]	= "Super Program",
121 	[CPU_SPACE]	= "CPU"
122 };
123 
124 void die_if_kernel(char *,struct pt_regs *,int);
125 asmlinkage int do_page_fault(struct pt_regs *regs, unsigned long address,
126                              unsigned long error_code);
127 int send_fault_sig(struct pt_regs *regs);
128 
129 asmlinkage void trap_c(struct frame *fp);
130 
131 #if defined (CONFIG_M68060)
132 static inline void access_error060 (struct frame *fp)
133 {
134 	unsigned long fslw = fp->un.fmt4.pc; /* is really FSLW for access error */
135 
136 	pr_debug("fslw=%#lx, fa=%#lx\n", fslw, fp->un.fmt4.effaddr);
137 
138 	if (fslw & MMU060_BPE) {
139 		/* branch prediction error -> clear branch cache */
140 		__asm__ __volatile__ ("movec %/cacr,%/d0\n\t"
141 				      "orl   #0x00400000,%/d0\n\t"
142 				      "movec %/d0,%/cacr"
143 				      : : : "d0" );
144 		/* return if there's no other error */
145 		if (!(fslw & MMU060_ERR_BITS) && !(fslw & MMU060_SEE))
146 			return;
147 	}
148 
149 	if (fslw & (MMU060_DESC_ERR | MMU060_WP | MMU060_SP)) {
150 		unsigned long errorcode;
151 		unsigned long addr = fp->un.fmt4.effaddr;
152 
153 		if (fslw & MMU060_MA)
154 			addr = (addr + PAGE_SIZE - 1) & PAGE_MASK;
155 
156 		errorcode = 1;
157 		if (fslw & MMU060_DESC_ERR) {
158 			__flush_tlb040_one(addr);
159 			errorcode = 0;
160 		}
161 		if (fslw & MMU060_W)
162 			errorcode |= 2;
163 		pr_debug("errorcode = %ld\n", errorcode);
164 		do_page_fault(&fp->ptregs, addr, errorcode);
165 	} else if (fslw & (MMU060_SEE)){
166 		/* Software Emulation Error.
167 		 * fault during mem_read/mem_write in ifpsp060/os.S
168 		 */
169 		send_fault_sig(&fp->ptregs);
170 	} else if (!(fslw & (MMU060_RE|MMU060_WE)) ||
171 		   send_fault_sig(&fp->ptregs) > 0) {
172 		pr_err("pc=%#lx, fa=%#lx\n", fp->ptregs.pc,
173 		       fp->un.fmt4.effaddr);
174 		pr_err("68060 access error, fslw=%lx\n", fslw);
175 		trap_c( fp );
176 	}
177 }
178 #endif /* CONFIG_M68060 */
179 
180 #if defined (CONFIG_M68040)
181 static inline unsigned long probe040(int iswrite, unsigned long addr, int wbs)
182 {
183 	unsigned long mmusr;
184 
185 	set_fc(wbs);
186 
187 	if (iswrite)
188 		asm volatile (".chip 68040; ptestw (%0); .chip 68k" : : "a" (addr));
189 	else
190 		asm volatile (".chip 68040; ptestr (%0); .chip 68k" : : "a" (addr));
191 
192 	asm volatile (".chip 68040; movec %%mmusr,%0; .chip 68k" : "=r" (mmusr));
193 
194 	set_fc(USER_DATA);
195 
196 	return mmusr;
197 }
198 
199 static inline int do_040writeback1(unsigned short wbs, unsigned long wba,
200 				   unsigned long wbd)
201 {
202 	int res = 0;
203 
204 	set_fc(wbs);
205 
206 	switch (wbs & WBSIZ_040) {
207 	case BA_SIZE_BYTE:
208 		res = put_user(wbd & 0xff, (char __user *)wba);
209 		break;
210 	case BA_SIZE_WORD:
211 		res = put_user(wbd & 0xffff, (short __user *)wba);
212 		break;
213 	case BA_SIZE_LONG:
214 		res = put_user(wbd, (int __user *)wba);
215 		break;
216 	}
217 
218 	set_fc(USER_DATA);
219 
220 	pr_debug("do_040writeback1, res=%d\n", res);
221 
222 	return res;
223 }
224 
225 /* after an exception in a writeback the stack frame corresponding
226  * to that exception is discarded, set a few bits in the old frame
227  * to simulate what it should look like
228  */
229 static inline void fix_xframe040(struct frame *fp, unsigned long wba, unsigned short wbs)
230 {
231 	fp->un.fmt7.faddr = wba;
232 	fp->un.fmt7.ssw = wbs & 0xff;
233 	if (wba != current->thread.faddr)
234 	    fp->un.fmt7.ssw |= MA_040;
235 }
236 
237 static inline void do_040writebacks(struct frame *fp)
238 {
239 	int res = 0;
240 #if 0
241 	if (fp->un.fmt7.wb1s & WBV_040)
242 		pr_err("access_error040: cannot handle 1st writeback. oops.\n");
243 #endif
244 
245 	if ((fp->un.fmt7.wb2s & WBV_040) &&
246 	    !(fp->un.fmt7.wb2s & WBTT_040)) {
247 		res = do_040writeback1(fp->un.fmt7.wb2s, fp->un.fmt7.wb2a,
248 				       fp->un.fmt7.wb2d);
249 		if (res)
250 			fix_xframe040(fp, fp->un.fmt7.wb2a, fp->un.fmt7.wb2s);
251 		else
252 			fp->un.fmt7.wb2s = 0;
253 	}
254 
255 	/* do the 2nd wb only if the first one was successful (except for a kernel wb) */
256 	if (fp->un.fmt7.wb3s & WBV_040 && (!res || fp->un.fmt7.wb3s & 4)) {
257 		res = do_040writeback1(fp->un.fmt7.wb3s, fp->un.fmt7.wb3a,
258 				       fp->un.fmt7.wb3d);
259 		if (res)
260 		    {
261 			fix_xframe040(fp, fp->un.fmt7.wb3a, fp->un.fmt7.wb3s);
262 
263 			fp->un.fmt7.wb2s = fp->un.fmt7.wb3s;
264 			fp->un.fmt7.wb3s &= (~WBV_040);
265 			fp->un.fmt7.wb2a = fp->un.fmt7.wb3a;
266 			fp->un.fmt7.wb2d = fp->un.fmt7.wb3d;
267 		    }
268 		else
269 			fp->un.fmt7.wb3s = 0;
270 	}
271 
272 	if (res)
273 		send_fault_sig(&fp->ptregs);
274 }
275 
276 /*
277  * called from sigreturn(), must ensure userspace code didn't
278  * manipulate exception frame to circumvent protection, then complete
279  * pending writebacks
280  * we just clear TM2 to turn it into a userspace access
281  */
282 asmlinkage void berr_040cleanup(struct frame *fp)
283 {
284 	fp->un.fmt7.wb2s &= ~4;
285 	fp->un.fmt7.wb3s &= ~4;
286 
287 	do_040writebacks(fp);
288 }
289 
290 static inline void access_error040(struct frame *fp)
291 {
292 	unsigned short ssw = fp->un.fmt7.ssw;
293 	unsigned long mmusr;
294 
295 	pr_debug("ssw=%#x, fa=%#lx\n", ssw, fp->un.fmt7.faddr);
296 	pr_debug("wb1s=%#x, wb2s=%#x, wb3s=%#x\n", fp->un.fmt7.wb1s,
297 		fp->un.fmt7.wb2s, fp->un.fmt7.wb3s);
298 	pr_debug("wb2a=%lx, wb3a=%lx, wb2d=%lx, wb3d=%lx\n",
299 		fp->un.fmt7.wb2a, fp->un.fmt7.wb3a,
300 		fp->un.fmt7.wb2d, fp->un.fmt7.wb3d);
301 
302 	if (ssw & ATC_040) {
303 		unsigned long addr = fp->un.fmt7.faddr;
304 		unsigned long errorcode;
305 
306 		/*
307 		 * The MMU status has to be determined AFTER the address
308 		 * has been corrected if there was a misaligned access (MA).
309 		 */
310 		if (ssw & MA_040)
311 			addr = (addr + 7) & -8;
312 
313 		/* MMU error, get the MMUSR info for this access */
314 		mmusr = probe040(!(ssw & RW_040), addr, ssw);
315 		pr_debug("mmusr = %lx\n", mmusr);
316 		errorcode = 1;
317 		if (!(mmusr & MMU_R_040)) {
318 			/* clear the invalid atc entry */
319 			__flush_tlb040_one(addr);
320 			errorcode = 0;
321 		}
322 
323 		/* despite what documentation seems to say, RMW
324 		 * accesses have always both the LK and RW bits set */
325 		if (!(ssw & RW_040) || (ssw & LK_040))
326 			errorcode |= 2;
327 
328 		if (do_page_fault(&fp->ptregs, addr, errorcode)) {
329 			pr_debug("do_page_fault() !=0\n");
330 			if (user_mode(&fp->ptregs)){
331 				/* delay writebacks after signal delivery */
332 				pr_debug(".. was usermode - return\n");
333 				return;
334 			}
335 			/* disable writeback into user space from kernel
336 			 * (if do_page_fault didn't fix the mapping,
337                          * the writeback won't do good)
338 			 */
339 disable_wb:
340 			pr_debug(".. disabling wb2\n");
341 			if (fp->un.fmt7.wb2a == fp->un.fmt7.faddr)
342 				fp->un.fmt7.wb2s &= ~WBV_040;
343 			if (fp->un.fmt7.wb3a == fp->un.fmt7.faddr)
344 				fp->un.fmt7.wb3s &= ~WBV_040;
345 		}
346 	} else {
347 		/* In case of a bus error we either kill the process or expect
348 		 * the kernel to catch the fault, which then is also responsible
349 		 * for cleaning up the mess.
350 		 */
351 		current->thread.signo = SIGBUS;
352 		current->thread.faddr = fp->un.fmt7.faddr;
353 		if (send_fault_sig(&fp->ptregs) >= 0)
354 			pr_err("68040 bus error (ssw=%x, faddr=%lx)\n", ssw,
355 			       fp->un.fmt7.faddr);
356 		goto disable_wb;
357 	}
358 
359 	do_040writebacks(fp);
360 }
361 #endif /* CONFIG_M68040 */
362 
363 #if defined(CONFIG_SUN3)
364 #include <asm/sun3mmu.h>
365 
366 extern int mmu_emu_handle_fault (unsigned long, int, int);
367 
368 /* sun3 version of bus_error030 */
369 
370 static inline void bus_error030 (struct frame *fp)
371 {
372 	unsigned char buserr_type = sun3_get_buserr ();
373 	unsigned long addr, errorcode;
374 	unsigned short ssw = fp->un.fmtb.ssw;
375 	extern unsigned long _sun3_map_test_start, _sun3_map_test_end;
376 
377 	if (ssw & (FC | FB))
378 		pr_debug("Instruction fault at %#010lx\n",
379 			ssw & FC ?
380 			fp->ptregs.format == 0xa ? fp->ptregs.pc + 2 : fp->un.fmtb.baddr - 2
381 			:
382 			fp->ptregs.format == 0xa ? fp->ptregs.pc + 4 : fp->un.fmtb.baddr);
383 	if (ssw & DF)
384 		pr_debug("Data %s fault at %#010lx in %s (pc=%#lx)\n",
385 			ssw & RW ? "read" : "write",
386 			fp->un.fmtb.daddr,
387 			space_names[ssw & DFC], fp->ptregs.pc);
388 
389 	/*
390 	 * Check if this page should be demand-mapped. This needs to go before
391 	 * the testing for a bad kernel-space access (demand-mapping applies
392 	 * to kernel accesses too).
393 	 */
394 
395 	if ((ssw & DF)
396 	    && (buserr_type & (SUN3_BUSERR_PROTERR | SUN3_BUSERR_INVALID))) {
397 		if (mmu_emu_handle_fault (fp->un.fmtb.daddr, ssw & RW, 0))
398 			return;
399 	}
400 
401 	/* Check for kernel-space pagefault (BAD). */
402 	if (fp->ptregs.sr & PS_S) {
403 		/* kernel fault must be a data fault to user space */
404 		if (! ((ssw & DF) && ((ssw & DFC) == USER_DATA))) {
405 		     // try checking the kernel mappings before surrender
406 		     if (mmu_emu_handle_fault (fp->un.fmtb.daddr, ssw & RW, 1))
407 			  return;
408 			/* instruction fault or kernel data fault! */
409 			if (ssw & (FC | FB))
410 				pr_err("Instruction fault at %#010lx\n",
411 					fp->ptregs.pc);
412 			if (ssw & DF) {
413 				/* was this fault incurred testing bus mappings? */
414 				if((fp->ptregs.pc >= (unsigned long)&_sun3_map_test_start) &&
415 				   (fp->ptregs.pc <= (unsigned long)&_sun3_map_test_end)) {
416 					send_fault_sig(&fp->ptregs);
417 					return;
418 				}
419 
420 				pr_err("Data %s fault at %#010lx in %s (pc=%#lx)\n",
421 					ssw & RW ? "read" : "write",
422 					fp->un.fmtb.daddr,
423 					space_names[ssw & DFC], fp->ptregs.pc);
424 			}
425 			pr_err("BAD KERNEL BUSERR\n");
426 
427 			die_if_kernel("Oops", &fp->ptregs,0);
428 			force_sig(SIGKILL);
429 			return;
430 		}
431 	} else {
432 		/* user fault */
433 		if (!(ssw & (FC | FB)) && !(ssw & DF))
434 			/* not an instruction fault or data fault! BAD */
435 			panic ("USER BUSERR w/o instruction or data fault");
436 	}
437 
438 
439 	/* First handle the data fault, if any.  */
440 	if (ssw & DF) {
441 		addr = fp->un.fmtb.daddr;
442 
443 // errorcode bit 0:	0 -> no page		1 -> protection fault
444 // errorcode bit 1:	0 -> read fault		1 -> write fault
445 
446 // (buserr_type & SUN3_BUSERR_PROTERR)	-> protection fault
447 // (buserr_type & SUN3_BUSERR_INVALID)	-> invalid page fault
448 
449 		if (buserr_type & SUN3_BUSERR_PROTERR)
450 			errorcode = 0x01;
451 		else if (buserr_type & SUN3_BUSERR_INVALID)
452 			errorcode = 0x00;
453 		else {
454 			pr_debug("*** unexpected busfault type=%#04x\n",
455 				 buserr_type);
456 			pr_debug("invalid %s access at %#lx from pc %#lx\n",
457 				 !(ssw & RW) ? "write" : "read", addr,
458 				 fp->ptregs.pc);
459 			die_if_kernel ("Oops", &fp->ptregs, buserr_type);
460 			force_sig (SIGBUS);
461 			return;
462 		}
463 
464 //todo: wtf is RM bit? --m
465 		if (!(ssw & RW) || ssw & RM)
466 			errorcode |= 0x02;
467 
468 		/* Handle page fault. */
469 		do_page_fault (&fp->ptregs, addr, errorcode);
470 
471 		/* Retry the data fault now. */
472 		return;
473 	}
474 
475 	/* Now handle the instruction fault. */
476 
477 	/* Get the fault address. */
478 	if (fp->ptregs.format == 0xA)
479 		addr = fp->ptregs.pc + 4;
480 	else
481 		addr = fp->un.fmtb.baddr;
482 	if (ssw & FC)
483 		addr -= 2;
484 
485 	if (buserr_type & SUN3_BUSERR_INVALID) {
486 		if (!mmu_emu_handle_fault(addr, 1, 0))
487 			do_page_fault (&fp->ptregs, addr, 0);
488        } else {
489 		pr_debug("protection fault on insn access (segv).\n");
490 		force_sig (SIGSEGV);
491        }
492 }
493 #else
494 #if defined(CPU_M68020_OR_M68030)
495 static inline void bus_error030 (struct frame *fp)
496 {
497 	volatile unsigned short temp;
498 	unsigned short mmusr;
499 	unsigned long addr, errorcode;
500 	unsigned short ssw = fp->un.fmtb.ssw;
501 #ifdef DEBUG
502 	unsigned long desc;
503 #endif
504 
505 	pr_debug("pid = %x  ", current->pid);
506 	pr_debug("SSW=%#06x  ", ssw);
507 
508 	if (ssw & (FC | FB))
509 		pr_debug("Instruction fault at %#010lx\n",
510 			ssw & FC ?
511 			fp->ptregs.format == 0xa ? fp->ptregs.pc + 2 : fp->un.fmtb.baddr - 2
512 			:
513 			fp->ptregs.format == 0xa ? fp->ptregs.pc + 4 : fp->un.fmtb.baddr);
514 	if (ssw & DF)
515 		pr_debug("Data %s fault at %#010lx in %s (pc=%#lx)\n",
516 			ssw & RW ? "read" : "write",
517 			fp->un.fmtb.daddr,
518 			space_names[ssw & DFC], fp->ptregs.pc);
519 
520 	/* ++andreas: If a data fault and an instruction fault happen
521 	   at the same time map in both pages.  */
522 
523 	/* First handle the data fault, if any.  */
524 	if (ssw & DF) {
525 		addr = fp->un.fmtb.daddr;
526 
527 #ifdef DEBUG
528 		asm volatile ("ptestr %3,%2@,#7,%0\n\t"
529 			      "pmove %%psr,%1"
530 			      : "=a&" (desc), "=m" (temp)
531 			      : "a" (addr), "d" (ssw));
532 		pr_debug("mmusr is %#x for addr %#lx in task %p\n",
533 			 temp, addr, current);
534 		pr_debug("descriptor address is 0x%p, contents %#lx\n",
535 			 __va(desc), *(unsigned long *)__va(desc));
536 #else
537 		asm volatile ("ptestr %2,%1@,#7\n\t"
538 			      "pmove %%psr,%0"
539 			      : "=m" (temp) : "a" (addr), "d" (ssw));
540 #endif
541 		mmusr = temp;
542 		errorcode = (mmusr & MMU_I) ? 0 : 1;
543 		if (!(ssw & RW) || (ssw & RM))
544 			errorcode |= 2;
545 
546 		if (mmusr & (MMU_I | MMU_WP)) {
547 			if (ssw & 4) {
548 				pr_err("Data %s fault at %#010lx in %s (pc=%#lx)\n",
549 				       ssw & RW ? "read" : "write",
550 				       fp->un.fmtb.daddr,
551 				       space_names[ssw & DFC], fp->ptregs.pc);
552 				goto buserr;
553 			}
554 			/* Don't try to do anything further if an exception was
555 			   handled. */
556 			if (do_page_fault (&fp->ptregs, addr, errorcode) < 0)
557 				return;
558 		} else if (!(mmusr & MMU_I)) {
559 			/* probably a 020 cas fault */
560 			if (!(ssw & RM) && send_fault_sig(&fp->ptregs) > 0)
561 				pr_err("unexpected bus error (%#x,%#x)\n", ssw,
562 				       mmusr);
563 		} else if (mmusr & (MMU_B|MMU_L|MMU_S)) {
564 			pr_err("invalid %s access at %#lx from pc %#lx\n",
565 			       !(ssw & RW) ? "write" : "read", addr,
566 			       fp->ptregs.pc);
567 			die_if_kernel("Oops",&fp->ptregs,mmusr);
568 			force_sig(SIGSEGV);
569 			return;
570 		} else {
571 #if 0
572 			static volatile long tlong;
573 #endif
574 
575 			pr_err("weird %s access at %#lx from pc %#lx (ssw is %#x)\n",
576 			       !(ssw & RW) ? "write" : "read", addr,
577 			       fp->ptregs.pc, ssw);
578 			asm volatile ("ptestr #1,%1@,#0\n\t"
579 				      "pmove %%psr,%0"
580 				      : "=m" (temp)
581 				      : "a" (addr));
582 			mmusr = temp;
583 
584 			pr_err("level 0 mmusr is %#x\n", mmusr);
585 #if 0
586 			asm volatile ("pmove %%tt0,%0"
587 				      : "=m" (tlong));
588 			pr_debug("tt0 is %#lx, ", tlong);
589 			asm volatile ("pmove %%tt1,%0"
590 				      : "=m" (tlong));
591 			pr_debug("tt1 is %#lx\n", tlong);
592 #endif
593 			pr_debug("Unknown SIGSEGV - 1\n");
594 			die_if_kernel("Oops",&fp->ptregs,mmusr);
595 			force_sig(SIGSEGV);
596 			return;
597 		}
598 
599 		/* setup an ATC entry for the access about to be retried */
600 		if (!(ssw & RW) || (ssw & RM))
601 			asm volatile ("ploadw %1,%0@" : /* no outputs */
602 				      : "a" (addr), "d" (ssw));
603 		else
604 			asm volatile ("ploadr %1,%0@" : /* no outputs */
605 				      : "a" (addr), "d" (ssw));
606 	}
607 
608 	/* Now handle the instruction fault. */
609 
610 	if (!(ssw & (FC|FB)))
611 		return;
612 
613 	if (fp->ptregs.sr & PS_S) {
614 		pr_err("Instruction fault at %#010lx\n", fp->ptregs.pc);
615 	buserr:
616 		pr_err("BAD KERNEL BUSERR\n");
617 		die_if_kernel("Oops",&fp->ptregs,0);
618 		force_sig(SIGKILL);
619 		return;
620 	}
621 
622 	/* get the fault address */
623 	if (fp->ptregs.format == 10)
624 		addr = fp->ptregs.pc + 4;
625 	else
626 		addr = fp->un.fmtb.baddr;
627 	if (ssw & FC)
628 		addr -= 2;
629 
630 	if ((ssw & DF) && ((addr ^ fp->un.fmtb.daddr) & PAGE_MASK) == 0)
631 		/* Insn fault on same page as data fault.  But we
632 		   should still create the ATC entry.  */
633 		goto create_atc_entry;
634 
635 #ifdef DEBUG
636 	asm volatile ("ptestr #1,%2@,#7,%0\n\t"
637 		      "pmove %%psr,%1"
638 		      : "=a&" (desc), "=m" (temp)
639 		      : "a" (addr));
640 	pr_debug("mmusr is %#x for addr %#lx in task %p\n",
641 		temp, addr, current);
642 	pr_debug("descriptor address is 0x%p, contents %#lx\n",
643 		__va(desc), *(unsigned long *)__va(desc));
644 #else
645 	asm volatile ("ptestr #1,%1@,#7\n\t"
646 		      "pmove %%psr,%0"
647 		      : "=m" (temp) : "a" (addr));
648 #endif
649 	mmusr = temp;
650 	if (mmusr & MMU_I)
651 		do_page_fault (&fp->ptregs, addr, 0);
652 	else if (mmusr & (MMU_B|MMU_L|MMU_S)) {
653 		pr_err("invalid insn access at %#lx from pc %#lx\n",
654 			addr, fp->ptregs.pc);
655 		pr_debug("Unknown SIGSEGV - 2\n");
656 		die_if_kernel("Oops",&fp->ptregs,mmusr);
657 		force_sig(SIGSEGV);
658 		return;
659 	}
660 
661 create_atc_entry:
662 	/* setup an ATC entry for the access about to be retried */
663 	asm volatile ("ploadr #2,%0@" : /* no outputs */
664 		      : "a" (addr));
665 }
666 #endif /* CPU_M68020_OR_M68030 */
667 #endif /* !CONFIG_SUN3 */
668 
669 #if defined(CONFIG_COLDFIRE) && defined(CONFIG_MMU)
670 #include <asm/mcfmmu.h>
671 
672 /*
673  *	The following table converts the FS encoding of a ColdFire
674  *	exception stack frame into the error_code value needed by
675  *	do_fault.
676 */
677 static const unsigned char fs_err_code[] = {
678 	0,  /* 0000 */
679 	0,  /* 0001 */
680 	0,  /* 0010 */
681 	0,  /* 0011 */
682 	1,  /* 0100 */
683 	0,  /* 0101 */
684 	0,  /* 0110 */
685 	0,  /* 0111 */
686 	2,  /* 1000 */
687 	3,  /* 1001 */
688 	2,  /* 1010 */
689 	0,  /* 1011 */
690 	1,  /* 1100 */
691 	1,  /* 1101 */
692 	0,  /* 1110 */
693 	0   /* 1111 */
694 };
695 
696 static inline void access_errorcf(unsigned int fs, struct frame *fp)
697 {
698 	unsigned long mmusr, addr;
699 	unsigned int err_code;
700 	int need_page_fault;
701 
702 	mmusr = mmu_read(MMUSR);
703 	addr = mmu_read(MMUAR);
704 
705 	/*
706 	 * error_code:
707 	 *	bit 0 == 0 means no page found, 1 means protection fault
708 	 *	bit 1 == 0 means read, 1 means write
709 	 */
710 	switch (fs) {
711 	case  5:  /* 0101 TLB opword X miss */
712 		need_page_fault = cf_tlb_miss(&fp->ptregs, 0, 0, 0);
713 		addr = fp->ptregs.pc;
714 		break;
715 	case  6:  /* 0110 TLB extension word X miss */
716 		need_page_fault = cf_tlb_miss(&fp->ptregs, 0, 0, 1);
717 		addr = fp->ptregs.pc + sizeof(long);
718 		break;
719 	case 10:  /* 1010 TLB W miss */
720 		need_page_fault = cf_tlb_miss(&fp->ptregs, 1, 1, 0);
721 		break;
722 	case 14: /* 1110 TLB R miss */
723 		need_page_fault = cf_tlb_miss(&fp->ptregs, 0, 1, 0);
724 		break;
725 	default:
726 		/* 0000 Normal  */
727 		/* 0001 Reserved */
728 		/* 0010 Interrupt during debug service routine */
729 		/* 0011 Reserved */
730 		/* 0100 X Protection */
731 		/* 0111 IFP in emulator mode */
732 		/* 1000 W Protection*/
733 		/* 1001 Write error*/
734 		/* 1011 Reserved*/
735 		/* 1100 R Protection*/
736 		/* 1101 R Protection*/
737 		/* 1111 OEP in emulator mode*/
738 		need_page_fault = 1;
739 		break;
740 	}
741 
742 	if (need_page_fault) {
743 		err_code = fs_err_code[fs];
744 		if ((fs == 13) && (mmusr & MMUSR_WF)) /* rd-mod-wr access */
745 			err_code |= 2; /* bit1 - write, bit0 - protection */
746 		do_page_fault(&fp->ptregs, addr, err_code);
747 	}
748 }
749 #endif /* CONFIG_COLDFIRE CONFIG_MMU */
750 
751 asmlinkage void buserr_c(struct frame *fp)
752 {
753 	/* Only set esp0 if coming from user mode */
754 	if (user_mode(&fp->ptregs))
755 		current->thread.esp0 = (unsigned long) fp;
756 
757 	pr_debug("*** Bus Error *** Format is %x\n", fp->ptregs.format);
758 
759 #if defined(CONFIG_COLDFIRE) && defined(CONFIG_MMU)
760 	if (CPU_IS_COLDFIRE) {
761 		unsigned int fs;
762 		fs = (fp->ptregs.vector & 0x3) |
763 			((fp->ptregs.vector & 0xc00) >> 8);
764 		switch (fs) {
765 		case 0x5:
766 		case 0x6:
767 		case 0x7:
768 		case 0x9:
769 		case 0xa:
770 		case 0xd:
771 		case 0xe:
772 		case 0xf:
773 			access_errorcf(fs, fp);
774 			return;
775 		default:
776 			break;
777 		}
778 	}
779 #endif /* CONFIG_COLDFIRE && CONFIG_MMU */
780 
781 	switch (fp->ptregs.format) {
782 #if defined (CONFIG_M68060)
783 	case 4:				/* 68060 access error */
784 	  access_error060 (fp);
785 	  break;
786 #endif
787 #if defined (CONFIG_M68040)
788 	case 0x7:			/* 68040 access error */
789 	  access_error040 (fp);
790 	  break;
791 #endif
792 #if defined (CPU_M68020_OR_M68030)
793 	case 0xa:
794 	case 0xb:
795 	  bus_error030 (fp);
796 	  break;
797 #endif
798 	default:
799 	  die_if_kernel("bad frame format",&fp->ptregs,0);
800 	  pr_debug("Unknown SIGSEGV - 4\n");
801 	  force_sig(SIGSEGV);
802 	}
803 }
804 
805 
806 static int kstack_depth_to_print = 48;
807 
808 static void show_trace(unsigned long *stack, const char *loglvl)
809 {
810 	unsigned long *endstack;
811 	unsigned long addr;
812 	int i;
813 
814 	printk("%sCall Trace:", loglvl);
815 	addr = (unsigned long)stack + THREAD_SIZE - 1;
816 	endstack = (unsigned long *)(addr & -THREAD_SIZE);
817 	i = 0;
818 	while (stack + 1 <= endstack) {
819 		addr = *stack++;
820 		/*
821 		 * If the address is either in the text segment of the
822 		 * kernel, or in the region which contains vmalloc'ed
823 		 * memory, it *may* be the address of a calling
824 		 * routine; if so, print it so that someone tracing
825 		 * down the cause of the crash will be able to figure
826 		 * out the call path that was taken.
827 		 */
828 		if (__kernel_text_address(addr)) {
829 #ifndef CONFIG_KALLSYMS
830 			if (i % 5 == 0)
831 				pr_cont("\n       ");
832 #endif
833 			pr_cont(" [<%08lx>] %pS\n", addr, (void *)addr);
834 			i++;
835 		}
836 	}
837 	pr_cont("\n");
838 }
839 
840 void show_registers(struct pt_regs *regs)
841 {
842 	struct frame *fp = (struct frame *)regs;
843 	u16 c, *cp;
844 	unsigned long addr;
845 	int i;
846 
847 	print_modules();
848 	pr_info("PC: [<%08lx>] %pS\n", regs->pc, (void *)regs->pc);
849 	pr_info("SR: %04x  SP: %p  a2: %08lx\n", regs->sr, regs, regs->a2);
850 	pr_info("d0: %08lx    d1: %08lx    d2: %08lx    d3: %08lx\n",
851 	       regs->d0, regs->d1, regs->d2, regs->d3);
852 	pr_info("d4: %08lx    d5: %08lx    a0: %08lx    a1: %08lx\n",
853 	       regs->d4, regs->d5, regs->a0, regs->a1);
854 
855 	pr_info("Process %s (pid: %d, task=%p)\n",
856 		current->comm, task_pid_nr(current), current);
857 	addr = (unsigned long)&fp->un;
858 	pr_info("Frame format=%X ", regs->format);
859 	switch (regs->format) {
860 	case 0x2:
861 		pr_cont("instr addr=%08lx\n", fp->un.fmt2.iaddr);
862 		addr += sizeof(fp->un.fmt2);
863 		break;
864 	case 0x3:
865 		pr_cont("eff addr=%08lx\n", fp->un.fmt3.effaddr);
866 		addr += sizeof(fp->un.fmt3);
867 		break;
868 	case 0x4:
869 		if (CPU_IS_060)
870 			pr_cont("fault addr=%08lx fslw=%08lx\n",
871 				fp->un.fmt4.effaddr, fp->un.fmt4.pc);
872 		else
873 			pr_cont("eff addr=%08lx pc=%08lx\n",
874 				fp->un.fmt4.effaddr, fp->un.fmt4.pc);
875 		addr += sizeof(fp->un.fmt4);
876 		break;
877 	case 0x7:
878 		pr_cont("eff addr=%08lx ssw=%04x faddr=%08lx\n",
879 			fp->un.fmt7.effaddr, fp->un.fmt7.ssw, fp->un.fmt7.faddr);
880 		pr_info("wb 1 stat/addr/data: %04x %08lx %08lx\n",
881 			fp->un.fmt7.wb1s, fp->un.fmt7.wb1a, fp->un.fmt7.wb1dpd0);
882 		pr_info("wb 2 stat/addr/data: %04x %08lx %08lx\n",
883 			fp->un.fmt7.wb2s, fp->un.fmt7.wb2a, fp->un.fmt7.wb2d);
884 		pr_info("wb 3 stat/addr/data: %04x %08lx %08lx\n",
885 			fp->un.fmt7.wb3s, fp->un.fmt7.wb3a, fp->un.fmt7.wb3d);
886 		pr_info("push data: %08lx %08lx %08lx %08lx\n",
887 			fp->un.fmt7.wb1dpd0, fp->un.fmt7.pd1, fp->un.fmt7.pd2,
888 			fp->un.fmt7.pd3);
889 		addr += sizeof(fp->un.fmt7);
890 		break;
891 	case 0x9:
892 		pr_cont("instr addr=%08lx\n", fp->un.fmt9.iaddr);
893 		addr += sizeof(fp->un.fmt9);
894 		break;
895 	case 0xa:
896 		pr_cont("ssw=%04x isc=%04x isb=%04x daddr=%08lx dobuf=%08lx\n",
897 			fp->un.fmta.ssw, fp->un.fmta.isc, fp->un.fmta.isb,
898 			fp->un.fmta.daddr, fp->un.fmta.dobuf);
899 		addr += sizeof(fp->un.fmta);
900 		break;
901 	case 0xb:
902 		pr_cont("ssw=%04x isc=%04x isb=%04x daddr=%08lx dobuf=%08lx\n",
903 			fp->un.fmtb.ssw, fp->un.fmtb.isc, fp->un.fmtb.isb,
904 			fp->un.fmtb.daddr, fp->un.fmtb.dobuf);
905 		pr_info("baddr=%08lx dibuf=%08lx ver=%x\n",
906 			fp->un.fmtb.baddr, fp->un.fmtb.dibuf, fp->un.fmtb.ver);
907 		addr += sizeof(fp->un.fmtb);
908 		break;
909 	default:
910 		pr_cont("\n");
911 	}
912 	show_stack(NULL, (unsigned long *)addr, KERN_INFO);
913 
914 	pr_info("Code:");
915 	cp = (u16 *)regs->pc;
916 	for (i = -8; i < 16; i++) {
917 		if (get_kernel_nofault(c, cp + i) && i >= 0) {
918 			pr_cont(" Bad PC value.");
919 			break;
920 		}
921 		if (i)
922 			pr_cont(" %04x", c);
923 		else
924 			pr_cont(" <%04x>", c);
925 	}
926 	pr_cont("\n");
927 }
928 
929 void show_stack(struct task_struct *task, unsigned long *stack,
930 		const char *loglvl)
931 {
932 	unsigned long *p;
933 	unsigned long *endstack;
934 	int i;
935 
936 	if (!stack) {
937 		if (task)
938 			stack = (unsigned long *)task->thread.esp0;
939 		else
940 			stack = (unsigned long *)&stack;
941 	}
942 	endstack = (unsigned long *)(((unsigned long)stack + THREAD_SIZE - 1) & -THREAD_SIZE);
943 
944 	printk("%sStack from %08lx:", loglvl, (unsigned long)stack);
945 	p = stack;
946 	for (i = 0; i < kstack_depth_to_print; i++) {
947 		if (p + 1 > endstack)
948 			break;
949 		if (i % 8 == 0)
950 			pr_cont("\n       ");
951 		pr_cont(" %08lx", *p++);
952 	}
953 	pr_cont("\n");
954 	show_trace(stack, loglvl);
955 }
956 
957 /*
958  * The vector number returned in the frame pointer may also contain
959  * the "fs" (Fault Status) bits on ColdFire. These are in the bottom
960  * 2 bits, and upper 2 bits. So we need to mask out the real vector
961  * number before using it in comparisons. You don't need to do this on
962  * real 68k parts, but it won't hurt either.
963  */
964 
965 void bad_super_trap (struct frame *fp)
966 {
967 	int vector = (fp->ptregs.vector >> 2) & 0xff;
968 
969 	console_verbose();
970 	if (vector < ARRAY_SIZE(vec_names))
971 		pr_err("*** %s ***   FORMAT=%X\n",
972 			vec_names[vector],
973 			fp->ptregs.format);
974 	else
975 		pr_err("*** Exception %d ***   FORMAT=%X\n",
976 			vector, fp->ptregs.format);
977 	if (vector == VEC_ADDRERR && CPU_IS_020_OR_030) {
978 		unsigned short ssw = fp->un.fmtb.ssw;
979 
980 		pr_err("SSW=%#06x  ", ssw);
981 
982 		if (ssw & RC)
983 			pr_err("Pipe stage C instruction fault at %#010lx\n",
984 				(fp->ptregs.format) == 0xA ?
985 				fp->ptregs.pc + 2 : fp->un.fmtb.baddr - 2);
986 		if (ssw & RB)
987 			pr_err("Pipe stage B instruction fault at %#010lx\n",
988 				(fp->ptregs.format) == 0xA ?
989 				fp->ptregs.pc + 4 : fp->un.fmtb.baddr);
990 		if (ssw & DF)
991 			pr_err("Data %s fault at %#010lx in %s (pc=%#lx)\n",
992 				ssw & RW ? "read" : "write",
993 				fp->un.fmtb.daddr, space_names[ssw & DFC],
994 				fp->ptregs.pc);
995 	}
996 	pr_err("Current process id is %d\n", task_pid_nr(current));
997 	die_if_kernel("BAD KERNEL TRAP", &fp->ptregs, 0);
998 }
999 
1000 asmlinkage void trap_c(struct frame *fp)
1001 {
1002 	int sig, si_code;
1003 	void __user *addr;
1004 	int vector = (fp->ptregs.vector >> 2) & 0xff;
1005 
1006 	if (fp->ptregs.sr & PS_S) {
1007 		if (vector == VEC_TRACE) {
1008 			/* traced a trapping instruction on a 68020/30,
1009 			 * real exception will be executed afterwards.
1010 			 */
1011 			return;
1012 		}
1013 #ifdef CONFIG_MMU
1014 		if (fixup_exception(&fp->ptregs))
1015 			return;
1016 #endif
1017 		bad_super_trap(fp);
1018 		return;
1019 	}
1020 
1021 	/* send the appropriate signal to the user program */
1022 	switch (vector) {
1023 	    case VEC_ADDRERR:
1024 		si_code = BUS_ADRALN;
1025 		sig = SIGBUS;
1026 		break;
1027 	    case VEC_ILLEGAL:
1028 	    case VEC_LINE10:
1029 	    case VEC_LINE11:
1030 		si_code = ILL_ILLOPC;
1031 		sig = SIGILL;
1032 		break;
1033 	    case VEC_PRIV:
1034 		si_code = ILL_PRVOPC;
1035 		sig = SIGILL;
1036 		break;
1037 	    case VEC_COPROC:
1038 		si_code = ILL_COPROC;
1039 		sig = SIGILL;
1040 		break;
1041 	    case VEC_TRAP1:
1042 	    case VEC_TRAP2:
1043 	    case VEC_TRAP3:
1044 	    case VEC_TRAP4:
1045 	    case VEC_TRAP5:
1046 	    case VEC_TRAP6:
1047 	    case VEC_TRAP7:
1048 	    case VEC_TRAP8:
1049 	    case VEC_TRAP9:
1050 	    case VEC_TRAP10:
1051 	    case VEC_TRAP11:
1052 	    case VEC_TRAP12:
1053 	    case VEC_TRAP13:
1054 	    case VEC_TRAP14:
1055 		si_code = ILL_ILLTRP;
1056 		sig = SIGILL;
1057 		break;
1058 	    case VEC_FPBRUC:
1059 	    case VEC_FPOE:
1060 	    case VEC_FPNAN:
1061 		si_code = FPE_FLTINV;
1062 		sig = SIGFPE;
1063 		break;
1064 	    case VEC_FPIR:
1065 		si_code = FPE_FLTRES;
1066 		sig = SIGFPE;
1067 		break;
1068 	    case VEC_FPDIVZ:
1069 		si_code = FPE_FLTDIV;
1070 		sig = SIGFPE;
1071 		break;
1072 	    case VEC_FPUNDER:
1073 		si_code = FPE_FLTUND;
1074 		sig = SIGFPE;
1075 		break;
1076 	    case VEC_FPOVER:
1077 		si_code = FPE_FLTOVF;
1078 		sig = SIGFPE;
1079 		break;
1080 	    case VEC_ZERODIV:
1081 		si_code = FPE_INTDIV;
1082 		sig = SIGFPE;
1083 		break;
1084 	    case VEC_CHK:
1085 	    case VEC_TRAP:
1086 		si_code = FPE_INTOVF;
1087 		sig = SIGFPE;
1088 		break;
1089 	    case VEC_TRACE:		/* ptrace single step */
1090 		si_code = TRAP_TRACE;
1091 		sig = SIGTRAP;
1092 		break;
1093 	    case VEC_TRAP15:		/* breakpoint */
1094 		si_code = TRAP_BRKPT;
1095 		sig = SIGTRAP;
1096 		break;
1097 	    default:
1098 		si_code = ILL_ILLOPC;
1099 		sig = SIGILL;
1100 		break;
1101 	}
1102 	switch (fp->ptregs.format) {
1103 	    default:
1104 		addr = (void __user *) fp->ptregs.pc;
1105 		break;
1106 	    case 2:
1107 		addr = (void __user *) fp->un.fmt2.iaddr;
1108 		break;
1109 	    case 7:
1110 		addr = (void __user *) fp->un.fmt7.effaddr;
1111 		break;
1112 	    case 9:
1113 		addr = (void __user *) fp->un.fmt9.iaddr;
1114 		break;
1115 	    case 10:
1116 		addr = (void __user *) fp->un.fmta.daddr;
1117 		break;
1118 	    case 11:
1119 		addr = (void __user*) fp->un.fmtb.daddr;
1120 		break;
1121 	}
1122 	force_sig_fault(sig, si_code, addr);
1123 }
1124 
1125 void die_if_kernel (char *str, struct pt_regs *fp, int nr)
1126 {
1127 	if (!(fp->sr & PS_S))
1128 		return;
1129 
1130 	console_verbose();
1131 	pr_crit("%s: %08x\n", str, nr);
1132 	show_registers(fp);
1133 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
1134 	do_exit(SIGSEGV);
1135 }
1136 
1137 asmlinkage void set_esp0(unsigned long ssp)
1138 {
1139 	current->thread.esp0 = ssp;
1140 }
1141 
1142 /*
1143  * This function is called if an error occur while accessing
1144  * user-space from the fpsp040 code.
1145  */
1146 asmlinkage void fpsp040_die(void)
1147 {
1148 	force_exit_sig(SIGSEGV);
1149 }
1150 
1151 #ifdef CONFIG_M68KFPU_EMU
1152 asmlinkage void fpemu_signal(int signal, int code, void *addr)
1153 {
1154 	force_sig_fault(signal, code, addr);
1155 }
1156 #endif
1157