1 /*
2 * Main exception handling logic.
3 *
4 * Copyright 2004-2010 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2 or later
7 */
8
9 #include <linux/bug.h>
10 #include <linux/uaccess.h>
11 #include <linux/module.h>
12 #include <asm/traps.h>
13 #include <asm/cplb.h>
14 #include <asm/blackfin.h>
15 #include <asm/irq_handler.h>
16 #include <linux/irq.h>
17 #include <asm/trace.h>
18 #include <asm/fixed_code.h>
19 #include <asm/pseudo_instructions.h>
20 #include <asm/pda.h>
21
22 #ifdef CONFIG_KGDB
23 # include <linux/kgdb.h>
24
25 # define CHK_DEBUGGER_TRAP() \
26 do { \
27 kgdb_handle_exception(trapnr, sig, info.si_code, fp); \
28 } while (0)
29 # define CHK_DEBUGGER_TRAP_MAYBE() \
30 do { \
31 if (kgdb_connected) \
32 CHK_DEBUGGER_TRAP(); \
33 } while (0)
34 #else
35 # define CHK_DEBUGGER_TRAP() do { } while (0)
36 # define CHK_DEBUGGER_TRAP_MAYBE() do { } while (0)
37 #endif
38
39
40 #ifdef CONFIG_DEBUG_VERBOSE
41 #define verbose_printk(fmt, arg...) \
42 printk(fmt, ##arg)
43 #else
44 #define verbose_printk(fmt, arg...) \
45 ({ if (0) printk(fmt, ##arg); 0; })
46 #endif
47
48 #if defined(CONFIG_DEBUG_MMRS) || defined(CONFIG_DEBUG_MMRS_MODULE)
49 u32 last_seqstat;
50 #ifdef CONFIG_DEBUG_MMRS_MODULE
51 EXPORT_SYMBOL(last_seqstat);
52 #endif
53 #endif
54
55 /* Initiate the event table handler */
trap_init(void)56 void __init trap_init(void)
57 {
58 CSYNC();
59 bfin_write_EVT3(trap);
60 CSYNC();
61 }
62
kernel_mode_regs(struct pt_regs * regs)63 static int kernel_mode_regs(struct pt_regs *regs)
64 {
65 return regs->ipend & 0xffc0;
66 }
67
trap_c(struct pt_regs * fp)68 asmlinkage notrace void trap_c(struct pt_regs *fp)
69 {
70 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
71 int j;
72 #endif
73 #ifdef CONFIG_BFIN_PSEUDODBG_INSNS
74 int opcode;
75 #endif
76 unsigned int cpu = raw_smp_processor_id();
77 const char *strerror = NULL;
78 int sig = 0;
79 siginfo_t info;
80 unsigned long trapnr = fp->seqstat & SEQSTAT_EXCAUSE;
81
82 trace_buffer_save(j);
83 #if defined(CONFIG_DEBUG_MMRS) || defined(CONFIG_DEBUG_MMRS_MODULE)
84 last_seqstat = (u32)fp->seqstat;
85 #endif
86
87 /* Important - be very careful dereferncing pointers - will lead to
88 * double faults if the stack has become corrupt
89 */
90
91 /* trap_c() will be called for exceptions. During exceptions
92 * processing, the pc value should be set with retx value.
93 * With this change we can cleanup some code in signal.c- TODO
94 */
95 fp->orig_pc = fp->retx;
96 /* printk("exception: 0x%x, ipend=%x, reti=%x, retx=%x\n",
97 trapnr, fp->ipend, fp->pc, fp->retx); */
98
99 /* send the appropriate signal to the user program */
100 switch (trapnr) {
101
102 /* This table works in conjunction with the one in ./mach-common/entry.S
103 * Some exceptions are handled there (in assembly, in exception space)
104 * Some are handled here, (in C, in interrupt space)
105 * Some, like CPLB, are handled in both, where the normal path is
106 * handled in assembly/exception space, and the error path is handled
107 * here
108 */
109
110 /* 0x00 - Linux Syscall, getting here is an error */
111 /* 0x01 - userspace gdb breakpoint, handled here */
112 case VEC_EXCPT01:
113 info.si_code = TRAP_ILLTRAP;
114 sig = SIGTRAP;
115 CHK_DEBUGGER_TRAP_MAYBE();
116 /* Check if this is a breakpoint in kernel space */
117 if (kernel_mode_regs(fp))
118 goto traps_done;
119 else
120 break;
121 /* 0x03 - User Defined, userspace stack overflow */
122 case VEC_EXCPT03:
123 info.si_code = SEGV_STACKFLOW;
124 sig = SIGSEGV;
125 strerror = KERN_NOTICE EXC_0x03(KERN_NOTICE);
126 CHK_DEBUGGER_TRAP_MAYBE();
127 break;
128 /* 0x02 - KGDB initial connection and break signal trap */
129 case VEC_EXCPT02:
130 #ifdef CONFIG_KGDB
131 info.si_code = TRAP_ILLTRAP;
132 sig = SIGTRAP;
133 CHK_DEBUGGER_TRAP();
134 goto traps_done;
135 #endif
136 /* 0x04 - User Defined */
137 /* 0x05 - User Defined */
138 /* 0x06 - User Defined */
139 /* 0x07 - User Defined */
140 /* 0x08 - User Defined */
141 /* 0x09 - User Defined */
142 /* 0x0A - User Defined */
143 /* 0x0B - User Defined */
144 /* 0x0C - User Defined */
145 /* 0x0D - User Defined */
146 /* 0x0E - User Defined */
147 /* 0x0F - User Defined */
148 /* If we got here, it is most likely that someone was trying to use a
149 * custom exception handler, and it is not actually installed properly
150 */
151 case VEC_EXCPT04 ... VEC_EXCPT15:
152 info.si_code = ILL_ILLPARAOP;
153 sig = SIGILL;
154 strerror = KERN_NOTICE EXC_0x04(KERN_NOTICE);
155 CHK_DEBUGGER_TRAP_MAYBE();
156 break;
157 /* 0x10 HW Single step, handled here */
158 case VEC_STEP:
159 info.si_code = TRAP_STEP;
160 sig = SIGTRAP;
161 CHK_DEBUGGER_TRAP_MAYBE();
162 /* Check if this is a single step in kernel space */
163 if (kernel_mode_regs(fp))
164 goto traps_done;
165 else
166 break;
167 /* 0x11 - Trace Buffer Full, handled here */
168 case VEC_OVFLOW:
169 info.si_code = TRAP_TRACEFLOW;
170 sig = SIGTRAP;
171 strerror = KERN_NOTICE EXC_0x11(KERN_NOTICE);
172 CHK_DEBUGGER_TRAP_MAYBE();
173 break;
174 /* 0x12 - Reserved, Caught by default */
175 /* 0x13 - Reserved, Caught by default */
176 /* 0x14 - Reserved, Caught by default */
177 /* 0x15 - Reserved, Caught by default */
178 /* 0x16 - Reserved, Caught by default */
179 /* 0x17 - Reserved, Caught by default */
180 /* 0x18 - Reserved, Caught by default */
181 /* 0x19 - Reserved, Caught by default */
182 /* 0x1A - Reserved, Caught by default */
183 /* 0x1B - Reserved, Caught by default */
184 /* 0x1C - Reserved, Caught by default */
185 /* 0x1D - Reserved, Caught by default */
186 /* 0x1E - Reserved, Caught by default */
187 /* 0x1F - Reserved, Caught by default */
188 /* 0x20 - Reserved, Caught by default */
189 /* 0x21 - Undefined Instruction, handled here */
190 case VEC_UNDEF_I:
191 #ifdef CONFIG_BUG
192 if (kernel_mode_regs(fp)) {
193 switch (report_bug(fp->pc, fp)) {
194 case BUG_TRAP_TYPE_NONE:
195 break;
196 case BUG_TRAP_TYPE_WARN:
197 dump_bfin_trace_buffer();
198 fp->pc += 2;
199 goto traps_done;
200 case BUG_TRAP_TYPE_BUG:
201 /* call to panic() will dump trace, and it is
202 * off at this point, so it won't be clobbered
203 */
204 panic("BUG()");
205 }
206 }
207 #endif
208 #ifdef CONFIG_BFIN_PSEUDODBG_INSNS
209 /*
210 * Support for the fake instructions, if the instruction fails,
211 * then just execute a illegal opcode failure (like normal).
212 * Don't support these instructions inside the kernel
213 */
214 if (!kernel_mode_regs(fp) && get_instruction(&opcode, (unsigned short *)fp->pc)) {
215 if (execute_pseudodbg_assert(fp, opcode))
216 goto traps_done;
217 if (execute_pseudodbg(fp, opcode))
218 goto traps_done;
219 }
220 #endif
221 info.si_code = ILL_ILLOPC;
222 sig = SIGILL;
223 strerror = KERN_NOTICE EXC_0x21(KERN_NOTICE);
224 CHK_DEBUGGER_TRAP_MAYBE();
225 break;
226 /* 0x22 - Illegal Instruction Combination, handled here */
227 case VEC_ILGAL_I:
228 info.si_code = ILL_ILLPARAOP;
229 sig = SIGILL;
230 strerror = KERN_NOTICE EXC_0x22(KERN_NOTICE);
231 CHK_DEBUGGER_TRAP_MAYBE();
232 break;
233 /* 0x23 - Data CPLB protection violation, handled here */
234 case VEC_CPLB_VL:
235 info.si_code = ILL_CPLB_VI;
236 sig = SIGSEGV;
237 strerror = KERN_NOTICE EXC_0x23(KERN_NOTICE);
238 CHK_DEBUGGER_TRAP_MAYBE();
239 break;
240 /* 0x24 - Data access misaligned, handled here */
241 case VEC_MISALI_D:
242 info.si_code = BUS_ADRALN;
243 sig = SIGBUS;
244 strerror = KERN_NOTICE EXC_0x24(KERN_NOTICE);
245 CHK_DEBUGGER_TRAP_MAYBE();
246 break;
247 /* 0x25 - Unrecoverable Event, handled here */
248 case VEC_UNCOV:
249 info.si_code = ILL_ILLEXCPT;
250 sig = SIGILL;
251 strerror = KERN_NOTICE EXC_0x25(KERN_NOTICE);
252 CHK_DEBUGGER_TRAP_MAYBE();
253 break;
254 /* 0x26 - Data CPLB Miss, normal case is handled in _cplb_hdr,
255 error case is handled here */
256 case VEC_CPLB_M:
257 info.si_code = BUS_ADRALN;
258 sig = SIGBUS;
259 strerror = KERN_NOTICE EXC_0x26(KERN_NOTICE);
260 break;
261 /* 0x27 - Data CPLB Multiple Hits - Linux Trap Zero, handled here */
262 case VEC_CPLB_MHIT:
263 info.si_code = ILL_CPLB_MULHIT;
264 sig = SIGSEGV;
265 #ifdef CONFIG_DEBUG_HUNT_FOR_ZERO
266 if (cpu_pda[cpu].dcplb_fault_addr < FIXED_CODE_START)
267 strerror = KERN_NOTICE "NULL pointer access\n";
268 else
269 #endif
270 strerror = KERN_NOTICE EXC_0x27(KERN_NOTICE);
271 CHK_DEBUGGER_TRAP_MAYBE();
272 break;
273 /* 0x28 - Emulation Watchpoint, handled here */
274 case VEC_WATCH:
275 info.si_code = TRAP_WATCHPT;
276 sig = SIGTRAP;
277 pr_debug(EXC_0x28(KERN_DEBUG));
278 CHK_DEBUGGER_TRAP_MAYBE();
279 /* Check if this is a watchpoint in kernel space */
280 if (kernel_mode_regs(fp))
281 goto traps_done;
282 else
283 break;
284 #ifdef CONFIG_BF535
285 /* 0x29 - Instruction fetch access error (535 only) */
286 case VEC_ISTRU_VL: /* ADSP-BF535 only (MH) */
287 info.si_code = BUS_OPFETCH;
288 sig = SIGBUS;
289 strerror = KERN_NOTICE "BF535: VEC_ISTRU_VL\n";
290 CHK_DEBUGGER_TRAP_MAYBE();
291 break;
292 #else
293 /* 0x29 - Reserved, Caught by default */
294 #endif
295 /* 0x2A - Instruction fetch misaligned, handled here */
296 case VEC_MISALI_I:
297 info.si_code = BUS_ADRALN;
298 sig = SIGBUS;
299 strerror = KERN_NOTICE EXC_0x2A(KERN_NOTICE);
300 CHK_DEBUGGER_TRAP_MAYBE();
301 break;
302 /* 0x2B - Instruction CPLB protection violation, handled here */
303 case VEC_CPLB_I_VL:
304 info.si_code = ILL_CPLB_VI;
305 sig = SIGBUS;
306 strerror = KERN_NOTICE EXC_0x2B(KERN_NOTICE);
307 CHK_DEBUGGER_TRAP_MAYBE();
308 break;
309 /* 0x2C - Instruction CPLB miss, handled in _cplb_hdr */
310 case VEC_CPLB_I_M:
311 info.si_code = ILL_CPLB_MISS;
312 sig = SIGBUS;
313 strerror = KERN_NOTICE EXC_0x2C(KERN_NOTICE);
314 break;
315 /* 0x2D - Instruction CPLB Multiple Hits, handled here */
316 case VEC_CPLB_I_MHIT:
317 info.si_code = ILL_CPLB_MULHIT;
318 sig = SIGSEGV;
319 #ifdef CONFIG_DEBUG_HUNT_FOR_ZERO
320 if (cpu_pda[cpu].icplb_fault_addr < FIXED_CODE_START)
321 strerror = KERN_NOTICE "Jump to NULL address\n";
322 else
323 #endif
324 strerror = KERN_NOTICE EXC_0x2D(KERN_NOTICE);
325 CHK_DEBUGGER_TRAP_MAYBE();
326 break;
327 /* 0x2E - Illegal use of Supervisor Resource, handled here */
328 case VEC_ILL_RES:
329 info.si_code = ILL_PRVOPC;
330 sig = SIGILL;
331 strerror = KERN_NOTICE EXC_0x2E(KERN_NOTICE);
332 CHK_DEBUGGER_TRAP_MAYBE();
333 break;
334 /* 0x2F - Reserved, Caught by default */
335 /* 0x30 - Reserved, Caught by default */
336 /* 0x31 - Reserved, Caught by default */
337 /* 0x32 - Reserved, Caught by default */
338 /* 0x33 - Reserved, Caught by default */
339 /* 0x34 - Reserved, Caught by default */
340 /* 0x35 - Reserved, Caught by default */
341 /* 0x36 - Reserved, Caught by default */
342 /* 0x37 - Reserved, Caught by default */
343 /* 0x38 - Reserved, Caught by default */
344 /* 0x39 - Reserved, Caught by default */
345 /* 0x3A - Reserved, Caught by default */
346 /* 0x3B - Reserved, Caught by default */
347 /* 0x3C - Reserved, Caught by default */
348 /* 0x3D - Reserved, Caught by default */
349 /* 0x3E - Reserved, Caught by default */
350 /* 0x3F - Reserved, Caught by default */
351 case VEC_HWERR:
352 info.si_code = BUS_ADRALN;
353 sig = SIGBUS;
354 switch (fp->seqstat & SEQSTAT_HWERRCAUSE) {
355 /* System MMR Error */
356 case (SEQSTAT_HWERRCAUSE_SYSTEM_MMR):
357 info.si_code = BUS_ADRALN;
358 sig = SIGBUS;
359 strerror = KERN_NOTICE HWC_x2(KERN_NOTICE);
360 break;
361 /* External Memory Addressing Error */
362 case (SEQSTAT_HWERRCAUSE_EXTERN_ADDR):
363 if (ANOMALY_05000310) {
364 static unsigned long anomaly_rets;
365
366 if ((fp->pc >= (L1_CODE_START + L1_CODE_LENGTH - 512)) &&
367 (fp->pc < (L1_CODE_START + L1_CODE_LENGTH))) {
368 /*
369 * A false hardware error will happen while fetching at
370 * the L1 instruction SRAM boundary. Ignore it.
371 */
372 anomaly_rets = fp->rets;
373 goto traps_done;
374 } else if (fp->rets == anomaly_rets) {
375 /*
376 * While boundary code returns to a function, at the ret
377 * point, a new false hardware error might occur too based
378 * on tests. Ignore it too.
379 */
380 goto traps_done;
381 } else if ((fp->rets >= (L1_CODE_START + L1_CODE_LENGTH - 512)) &&
382 (fp->rets < (L1_CODE_START + L1_CODE_LENGTH))) {
383 /*
384 * If boundary code calls a function, at the entry point,
385 * a new false hardware error maybe happen based on tests.
386 * Ignore it too.
387 */
388 goto traps_done;
389 } else
390 anomaly_rets = 0;
391 }
392
393 info.si_code = BUS_ADRERR;
394 sig = SIGBUS;
395 strerror = KERN_NOTICE HWC_x3(KERN_NOTICE);
396 break;
397 /* Performance Monitor Overflow */
398 case (SEQSTAT_HWERRCAUSE_PERF_FLOW):
399 strerror = KERN_NOTICE HWC_x12(KERN_NOTICE);
400 break;
401 /* RAISE 5 instruction */
402 case (SEQSTAT_HWERRCAUSE_RAISE_5):
403 printk(KERN_NOTICE HWC_x18(KERN_NOTICE));
404 break;
405 default: /* Reserved */
406 printk(KERN_NOTICE HWC_default(KERN_NOTICE));
407 break;
408 }
409 CHK_DEBUGGER_TRAP_MAYBE();
410 break;
411 /*
412 * We should be handling all known exception types above,
413 * if we get here we hit a reserved one, so panic
414 */
415 default:
416 info.si_code = ILL_ILLPARAOP;
417 sig = SIGILL;
418 verbose_printk(KERN_EMERG "Caught Unhandled Exception, code = %08lx\n",
419 (fp->seqstat & SEQSTAT_EXCAUSE));
420 CHK_DEBUGGER_TRAP_MAYBE();
421 break;
422 }
423
424 BUG_ON(sig == 0);
425
426 /* If the fault was caused by a kernel thread, or interrupt handler
427 * we will kernel panic, so the system reboots.
428 */
429 if (kernel_mode_regs(fp) || (current && !current->mm)) {
430 console_verbose();
431 oops_in_progress = 1;
432 }
433
434 if (sig != SIGTRAP) {
435 if (strerror)
436 verbose_printk(strerror);
437
438 dump_bfin_process(fp);
439 dump_bfin_mem(fp);
440 show_regs(fp);
441
442 /* Print out the trace buffer if it makes sense */
443 #ifndef CONFIG_DEBUG_BFIN_NO_KERN_HWTRACE
444 if (trapnr == VEC_CPLB_I_M || trapnr == VEC_CPLB_M)
445 verbose_printk(KERN_NOTICE "No trace since you do not have "
446 "CONFIG_DEBUG_BFIN_NO_KERN_HWTRACE enabled\n\n");
447 else
448 #endif
449 dump_bfin_trace_buffer();
450
451 if (oops_in_progress) {
452 /* Dump the current kernel stack */
453 verbose_printk(KERN_NOTICE "Kernel Stack\n");
454 show_stack(current, NULL);
455 print_modules();
456 #ifndef CONFIG_ACCESS_CHECK
457 verbose_printk(KERN_EMERG "Please turn on "
458 "CONFIG_ACCESS_CHECK\n");
459 #endif
460 panic("Kernel exception");
461 } else {
462 #ifdef CONFIG_DEBUG_VERBOSE
463 unsigned long *stack;
464 /* Dump the user space stack */
465 stack = (unsigned long *)rdusp();
466 verbose_printk(KERN_NOTICE "Userspace Stack\n");
467 show_stack(NULL, stack);
468 #endif
469 }
470 }
471
472 #ifdef CONFIG_IPIPE
473 if (!ipipe_trap_notify(fp->seqstat & 0x3f, fp))
474 #endif
475 {
476 info.si_signo = sig;
477 info.si_errno = 0;
478 switch (trapnr) {
479 case VEC_CPLB_VL:
480 case VEC_MISALI_D:
481 case VEC_CPLB_M:
482 case VEC_CPLB_MHIT:
483 info.si_addr = (void __user *)cpu_pda[cpu].dcplb_fault_addr;
484 break;
485 default:
486 info.si_addr = (void __user *)fp->pc;
487 break;
488 }
489 force_sig_info(sig, &info, current);
490 }
491
492 if ((ANOMALY_05000461 && trapnr == VEC_HWERR && !access_ok(VERIFY_READ, fp->pc, 8)) ||
493 (ANOMALY_05000281 && trapnr == VEC_HWERR) ||
494 (ANOMALY_05000189 && (trapnr == VEC_CPLB_I_VL || trapnr == VEC_CPLB_VL)))
495 fp->pc = SAFE_USER_INSTRUCTION;
496
497 traps_done:
498 trace_buffer_restore(j);
499 }
500
double_fault_c(struct pt_regs * fp)501 asmlinkage void double_fault_c(struct pt_regs *fp)
502 {
503 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
504 int j;
505 trace_buffer_save(j);
506 #endif
507
508 console_verbose();
509 oops_in_progress = 1;
510 #ifdef CONFIG_DEBUG_VERBOSE
511 printk(KERN_EMERG "Double Fault\n");
512 #ifdef CONFIG_DEBUG_DOUBLEFAULT_PRINT
513 if (((long)fp->seqstat & SEQSTAT_EXCAUSE) == VEC_UNCOV) {
514 unsigned int cpu = raw_smp_processor_id();
515 char buf[150];
516 decode_address(buf, cpu_pda[cpu].retx_doublefault);
517 printk(KERN_EMERG "While handling exception (EXCAUSE = 0x%x) at %s:\n",
518 (unsigned int)cpu_pda[cpu].seqstat_doublefault & SEQSTAT_EXCAUSE, buf);
519 decode_address(buf, cpu_pda[cpu].dcplb_doublefault_addr);
520 printk(KERN_NOTICE " DCPLB_FAULT_ADDR: %s\n", buf);
521 decode_address(buf, cpu_pda[cpu].icplb_doublefault_addr);
522 printk(KERN_NOTICE " ICPLB_FAULT_ADDR: %s\n", buf);
523
524 decode_address(buf, fp->retx);
525 printk(KERN_NOTICE "The instruction at %s caused a double exception\n", buf);
526 } else
527 #endif
528 {
529 dump_bfin_process(fp);
530 dump_bfin_mem(fp);
531 show_regs(fp);
532 dump_bfin_trace_buffer();
533 }
534 #endif
535 panic("Double Fault - unrecoverable event");
536
537 }
538
539
panic_cplb_error(int cplb_panic,struct pt_regs * fp)540 void panic_cplb_error(int cplb_panic, struct pt_regs *fp)
541 {
542 switch (cplb_panic) {
543 case CPLB_NO_UNLOCKED:
544 printk(KERN_EMERG "All CPLBs are locked\n");
545 break;
546 case CPLB_PROT_VIOL:
547 return;
548 case CPLB_NO_ADDR_MATCH:
549 return;
550 case CPLB_UNKNOWN_ERR:
551 printk(KERN_EMERG "Unknown CPLB Exception\n");
552 break;
553 }
554
555 oops_in_progress = 1;
556
557 dump_bfin_process(fp);
558 dump_bfin_mem(fp);
559 show_regs(fp);
560 dump_stack();
561 panic("Unrecoverable event");
562 }
563
564 #ifdef CONFIG_BUG
is_valid_bugaddr(unsigned long addr)565 int is_valid_bugaddr(unsigned long addr)
566 {
567 unsigned int opcode;
568
569 if (!get_instruction(&opcode, (unsigned short *)addr))
570 return 0;
571
572 return opcode == BFIN_BUG_OPCODE;
573 }
574 #endif
575
576 /* stub this out */
577 #ifndef CONFIG_DEBUG_VERBOSE
show_regs(struct pt_regs * fp)578 void show_regs(struct pt_regs *fp)
579 {
580
581 }
582 #endif
583