Merge tag 'arc-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
[sfrench/cifs-2.6.git] / arch / blackfin / kernel / traps.c
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 #include <asm/asm-offsets.h>
22
23 #ifdef CONFIG_KGDB
24 # include <linux/kgdb.h>
25
26 # define CHK_DEBUGGER_TRAP() \
27         do { \
28                 kgdb_handle_exception(trapnr, sig, info.si_code, fp); \
29         } while (0)
30 # define CHK_DEBUGGER_TRAP_MAYBE() \
31         do { \
32                 if (kgdb_connected) \
33                         CHK_DEBUGGER_TRAP(); \
34         } while (0)
35 #else
36 # define CHK_DEBUGGER_TRAP() do { } while (0)
37 # define CHK_DEBUGGER_TRAP_MAYBE() do { } while (0)
38 #endif
39
40
41 #ifdef CONFIG_DEBUG_VERBOSE
42 #define verbose_printk(fmt, arg...) \
43         printk(fmt, ##arg)
44 #else
45 #define verbose_printk(fmt, arg...) \
46         ({ if (0) printk(fmt, ##arg); 0; })
47 #endif
48
49 #if defined(CONFIG_DEBUG_MMRS) || defined(CONFIG_DEBUG_MMRS_MODULE)
50 u32 last_seqstat;
51 #ifdef CONFIG_DEBUG_MMRS_MODULE
52 EXPORT_SYMBOL(last_seqstat);
53 #endif
54 #endif
55
56 /* Initiate the event table handler */
57 void __init trap_init(void)
58 {
59         CSYNC();
60         bfin_write_EVT3(trap);
61         CSYNC();
62 }
63
64 static int kernel_mode_regs(struct pt_regs *regs)
65 {
66         return regs->ipend & 0xffc0;
67 }
68
69 asmlinkage notrace void trap_c(struct pt_regs *fp)
70 {
71 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
72         int j;
73 #endif
74 #ifdef CONFIG_BFIN_PSEUDODBG_INSNS
75         int opcode;
76 #endif
77         unsigned int cpu = raw_smp_processor_id();
78         const char *strerror = NULL;
79         int sig = 0;
80         siginfo_t info;
81         unsigned long trapnr = fp->seqstat & SEQSTAT_EXCAUSE;
82
83         trace_buffer_save(j);
84 #if defined(CONFIG_DEBUG_MMRS) || defined(CONFIG_DEBUG_MMRS_MODULE)
85         last_seqstat = (u32)fp->seqstat;
86 #endif
87
88         /* Important - be very careful dereferncing pointers - will lead to
89          * double faults if the stack has become corrupt
90          */
91
92         /* trap_c() will be called for exceptions. During exceptions
93          * processing, the pc value should be set with retx value.
94          * With this change we can cleanup some code in signal.c- TODO
95          */
96         fp->orig_pc = fp->retx;
97         /* printk("exception: 0x%x, ipend=%x, reti=%x, retx=%x\n",
98                 trapnr, fp->ipend, fp->pc, fp->retx); */
99
100         /* send the appropriate signal to the user program */
101         switch (trapnr) {
102
103         /* This table works in conjunction with the one in ./mach-common/entry.S
104          * Some exceptions are handled there (in assembly, in exception space)
105          * Some are handled here, (in C, in interrupt space)
106          * Some, like CPLB, are handled in both, where the normal path is
107          * handled in assembly/exception space, and the error path is handled
108          * here
109          */
110
111         /* 0x00 - Linux Syscall, getting here is an error */
112         /* 0x01 - userspace gdb breakpoint, handled here */
113         case VEC_EXCPT01:
114                 info.si_code = TRAP_ILLTRAP;
115                 sig = SIGTRAP;
116                 CHK_DEBUGGER_TRAP_MAYBE();
117                 /* Check if this is a breakpoint in kernel space */
118                 if (kernel_mode_regs(fp))
119                         goto traps_done;
120                 else
121                         break;
122         /* 0x03 - User Defined, userspace stack overflow */
123         case VEC_EXCPT03:
124                 info.si_code = SEGV_STACKFLOW;
125                 sig = SIGSEGV;
126                 strerror = KERN_NOTICE EXC_0x03(KERN_NOTICE);
127                 CHK_DEBUGGER_TRAP_MAYBE();
128                 break;
129         /* 0x02 - KGDB initial connection and break signal trap */
130         case VEC_EXCPT02:
131 #ifdef CONFIG_KGDB
132                 info.si_code = TRAP_ILLTRAP;
133                 sig = SIGTRAP;
134                 CHK_DEBUGGER_TRAP();
135                 goto traps_done;
136 #endif
137         /* 0x04 - User Defined */
138         /* 0x05 - User Defined */
139         /* 0x06 - User Defined */
140         /* 0x07 - User Defined */
141         /* 0x08 - User Defined */
142         /* 0x09 - User Defined */
143         /* 0x0A - User Defined */
144         /* 0x0B - User Defined */
145         /* 0x0C - User Defined */
146         /* 0x0D - User Defined */
147         /* 0x0E - User Defined */
148         /* 0x0F - User Defined */
149         /* If we got here, it is most likely that someone was trying to use a
150          * custom exception handler, and it is not actually installed properly
151          */
152         case VEC_EXCPT04 ... VEC_EXCPT15:
153                 info.si_code = ILL_ILLPARAOP;
154                 sig = SIGILL;
155                 strerror = KERN_NOTICE EXC_0x04(KERN_NOTICE);
156                 CHK_DEBUGGER_TRAP_MAYBE();
157                 break;
158         /* 0x10 HW Single step, handled here */
159         case VEC_STEP:
160                 info.si_code = TRAP_STEP;
161                 sig = SIGTRAP;
162                 CHK_DEBUGGER_TRAP_MAYBE();
163                 /* Check if this is a single step in kernel space */
164                 if (kernel_mode_regs(fp))
165                         goto traps_done;
166                 else
167                         break;
168         /* 0x11 - Trace Buffer Full, handled here */
169         case VEC_OVFLOW:
170                 info.si_code = TRAP_TRACEFLOW;
171                 sig = SIGTRAP;
172                 strerror = KERN_NOTICE EXC_0x11(KERN_NOTICE);
173                 CHK_DEBUGGER_TRAP_MAYBE();
174                 break;
175         /* 0x12 - Reserved, Caught by default */
176         /* 0x13 - Reserved, Caught by default */
177         /* 0x14 - Reserved, Caught by default */
178         /* 0x15 - Reserved, Caught by default */
179         /* 0x16 - Reserved, Caught by default */
180         /* 0x17 - Reserved, Caught by default */
181         /* 0x18 - Reserved, Caught by default */
182         /* 0x19 - Reserved, Caught by default */
183         /* 0x1A - Reserved, Caught by default */
184         /* 0x1B - Reserved, Caught by default */
185         /* 0x1C - Reserved, Caught by default */
186         /* 0x1D - Reserved, Caught by default */
187         /* 0x1E - Reserved, Caught by default */
188         /* 0x1F - Reserved, Caught by default */
189         /* 0x20 - Reserved, Caught by default */
190         /* 0x21 - Undefined Instruction, handled here */
191         case VEC_UNDEF_I:
192 #ifdef CONFIG_BUG
193                 if (kernel_mode_regs(fp)) {
194                         switch (report_bug(fp->pc, fp)) {
195                         case BUG_TRAP_TYPE_NONE:
196                                 break;
197                         case BUG_TRAP_TYPE_WARN:
198                                 dump_bfin_trace_buffer();
199                                 fp->pc += 2;
200                                 goto traps_done;
201                         case BUG_TRAP_TYPE_BUG:
202                                 /* call to panic() will dump trace, and it is
203                                  * off at this point, so it won't be clobbered
204                                  */
205                                 panic("BUG()");
206                         }
207                 }
208 #endif
209 #ifdef CONFIG_BFIN_PSEUDODBG_INSNS
210                 /*
211                  * Support for the fake instructions, if the instruction fails,
212                  * then just execute a illegal opcode failure (like normal).
213                  * Don't support these instructions inside the kernel
214                  */
215                 if (!kernel_mode_regs(fp) && get_instruction(&opcode, (unsigned short *)fp->pc)) {
216                         if (execute_pseudodbg_assert(fp, opcode))
217                                 goto traps_done;
218                         if (execute_pseudodbg(fp, opcode))
219                                 goto traps_done;
220                 }
221 #endif
222                 info.si_code = ILL_ILLOPC;
223                 sig = SIGILL;
224                 strerror = KERN_NOTICE EXC_0x21(KERN_NOTICE);
225                 CHK_DEBUGGER_TRAP_MAYBE();
226                 break;
227         /* 0x22 - Illegal Instruction Combination, handled here */
228         case VEC_ILGAL_I:
229                 info.si_code = ILL_ILLPARAOP;
230                 sig = SIGILL;
231                 strerror = KERN_NOTICE EXC_0x22(KERN_NOTICE);
232                 CHK_DEBUGGER_TRAP_MAYBE();
233                 break;
234         /* 0x23 - Data CPLB protection violation, handled here */
235         case VEC_CPLB_VL:
236                 info.si_code = ILL_CPLB_VI;
237                 sig = SIGSEGV;
238                 strerror = KERN_NOTICE EXC_0x23(KERN_NOTICE);
239                 CHK_DEBUGGER_TRAP_MAYBE();
240                 break;
241         /* 0x24 - Data access misaligned, handled here */
242         case VEC_MISALI_D:
243                 info.si_code = BUS_ADRALN;
244                 sig = SIGBUS;
245                 strerror = KERN_NOTICE EXC_0x24(KERN_NOTICE);
246                 CHK_DEBUGGER_TRAP_MAYBE();
247                 break;
248         /* 0x25 - Unrecoverable Event, handled here */
249         case VEC_UNCOV:
250                 info.si_code = ILL_ILLEXCPT;
251                 sig = SIGILL;
252                 strerror = KERN_NOTICE EXC_0x25(KERN_NOTICE);
253                 CHK_DEBUGGER_TRAP_MAYBE();
254                 break;
255         /* 0x26 - Data CPLB Miss, normal case is handled in _cplb_hdr,
256                 error case is handled here */
257         case VEC_CPLB_M:
258                 info.si_code = BUS_ADRALN;
259                 sig = SIGBUS;
260                 strerror = KERN_NOTICE EXC_0x26(KERN_NOTICE);
261                 break;
262         /* 0x27 - Data CPLB Multiple Hits - Linux Trap Zero, handled here */
263         case VEC_CPLB_MHIT:
264                 info.si_code = ILL_CPLB_MULHIT;
265                 sig = SIGSEGV;
266 #ifdef CONFIG_DEBUG_HUNT_FOR_ZERO
267                 if (cpu_pda[cpu].dcplb_fault_addr < FIXED_CODE_START)
268                         strerror = KERN_NOTICE "NULL pointer access\n";
269                 else
270 #endif
271                         strerror = KERN_NOTICE EXC_0x27(KERN_NOTICE);
272                 CHK_DEBUGGER_TRAP_MAYBE();
273                 break;
274         /* 0x28 - Emulation Watchpoint, handled here */
275         case VEC_WATCH:
276                 info.si_code = TRAP_WATCHPT;
277                 sig = SIGTRAP;
278                 pr_debug(EXC_0x28(KERN_DEBUG));
279                 CHK_DEBUGGER_TRAP_MAYBE();
280                 /* Check if this is a watchpoint in kernel space */
281                 if (kernel_mode_regs(fp))
282                         goto traps_done;
283                 else
284                         break;
285 #ifdef CONFIG_BF535
286         /* 0x29 - Instruction fetch access error (535 only) */
287         case VEC_ISTRU_VL:      /* ADSP-BF535 only (MH) */
288                 info.si_code = BUS_OPFETCH;
289                 sig = SIGBUS;
290                 strerror = KERN_NOTICE "BF535: VEC_ISTRU_VL\n";
291                 CHK_DEBUGGER_TRAP_MAYBE();
292                 break;
293 #else
294         /* 0x29 - Reserved, Caught by default */
295 #endif
296         /* 0x2A - Instruction fetch misaligned, handled here */
297         case VEC_MISALI_I:
298                 info.si_code = BUS_ADRALN;
299                 sig = SIGBUS;
300                 strerror = KERN_NOTICE EXC_0x2A(KERN_NOTICE);
301                 CHK_DEBUGGER_TRAP_MAYBE();
302                 break;
303         /* 0x2B - Instruction CPLB protection violation, handled here */
304         case VEC_CPLB_I_VL:
305                 info.si_code = ILL_CPLB_VI;
306                 sig = SIGBUS;
307                 strerror = KERN_NOTICE EXC_0x2B(KERN_NOTICE);
308                 CHK_DEBUGGER_TRAP_MAYBE();
309                 break;
310         /* 0x2C - Instruction CPLB miss, handled in _cplb_hdr */
311         case VEC_CPLB_I_M:
312                 info.si_code = ILL_CPLB_MISS;
313                 sig = SIGBUS;
314                 strerror = KERN_NOTICE EXC_0x2C(KERN_NOTICE);
315                 break;
316         /* 0x2D - Instruction CPLB Multiple Hits, handled here */
317         case VEC_CPLB_I_MHIT:
318                 info.si_code = ILL_CPLB_MULHIT;
319                 sig = SIGSEGV;
320 #ifdef CONFIG_DEBUG_HUNT_FOR_ZERO
321                 if (cpu_pda[cpu].icplb_fault_addr < FIXED_CODE_START)
322                         strerror = KERN_NOTICE "Jump to NULL address\n";
323                 else
324 #endif
325                         strerror = KERN_NOTICE EXC_0x2D(KERN_NOTICE);
326                 CHK_DEBUGGER_TRAP_MAYBE();
327                 break;
328         /* 0x2E - Illegal use of Supervisor Resource, handled here */
329         case VEC_ILL_RES:
330                 info.si_code = ILL_PRVOPC;
331                 sig = SIGILL;
332                 strerror = KERN_NOTICE EXC_0x2E(KERN_NOTICE);
333                 CHK_DEBUGGER_TRAP_MAYBE();
334                 break;
335         /* 0x2F - Reserved, Caught by default */
336         /* 0x30 - Reserved, Caught by default */
337         /* 0x31 - Reserved, Caught by default */
338         /* 0x32 - Reserved, Caught by default */
339         /* 0x33 - Reserved, Caught by default */
340         /* 0x34 - Reserved, Caught by default */
341         /* 0x35 - Reserved, Caught by default */
342         /* 0x36 - Reserved, Caught by default */
343         /* 0x37 - Reserved, Caught by default */
344         /* 0x38 - Reserved, Caught by default */
345         /* 0x39 - Reserved, Caught by default */
346         /* 0x3A - Reserved, Caught by default */
347         /* 0x3B - Reserved, Caught by default */
348         /* 0x3C - Reserved, Caught by default */
349         /* 0x3D - Reserved, Caught by default */
350         /* 0x3E - Reserved, Caught by default */
351         /* 0x3F - Reserved, Caught by default */
352         case VEC_HWERR:
353                 info.si_code = BUS_ADRALN;
354                 sig = SIGBUS;
355                 switch (fp->seqstat & SEQSTAT_HWERRCAUSE) {
356                 /* System MMR Error */
357                 case (SEQSTAT_HWERRCAUSE_SYSTEM_MMR):
358                         info.si_code = BUS_ADRALN;
359                         sig = SIGBUS;
360                         strerror = KERN_NOTICE HWC_x2(KERN_NOTICE);
361                         break;
362                 /* External Memory Addressing Error */
363                 case (SEQSTAT_HWERRCAUSE_EXTERN_ADDR):
364                         if (ANOMALY_05000310) {
365                                 static unsigned long anomaly_rets;
366
367                                 if ((fp->pc >= (L1_CODE_START + L1_CODE_LENGTH - 512)) &&
368                                     (fp->pc < (L1_CODE_START + L1_CODE_LENGTH))) {
369                                         /*
370                                          * A false hardware error will happen while fetching at
371                                          * the L1 instruction SRAM boundary.  Ignore it.
372                                          */
373                                         anomaly_rets = fp->rets;
374                                         goto traps_done;
375                                 } else if (fp->rets == anomaly_rets) {
376                                         /*
377                                          * While boundary code returns to a function, at the ret
378                                          * point, a new false hardware error might occur too based
379                                          * on tests.  Ignore it too.
380                                          */
381                                         goto traps_done;
382                                 } else if ((fp->rets >= (L1_CODE_START + L1_CODE_LENGTH - 512)) &&
383                                            (fp->rets < (L1_CODE_START + L1_CODE_LENGTH))) {
384                                         /*
385                                          * If boundary code calls a function, at the entry point,
386                                          * a new false hardware error maybe happen based on tests.
387                                          * Ignore it too.
388                                          */
389                                         goto traps_done;
390                                 } else
391                                         anomaly_rets = 0;
392                         }
393
394                         info.si_code = BUS_ADRERR;
395                         sig = SIGBUS;
396                         strerror = KERN_NOTICE HWC_x3(KERN_NOTICE);
397                         break;
398                 /* Performance Monitor Overflow */
399                 case (SEQSTAT_HWERRCAUSE_PERF_FLOW):
400                         strerror = KERN_NOTICE HWC_x12(KERN_NOTICE);
401                         break;
402                 /* RAISE 5 instruction */
403                 case (SEQSTAT_HWERRCAUSE_RAISE_5):
404                         printk(KERN_NOTICE HWC_x18(KERN_NOTICE));
405                         break;
406                 default:        /* Reserved */
407                         printk(KERN_NOTICE HWC_default(KERN_NOTICE));
408                         break;
409                 }
410                 CHK_DEBUGGER_TRAP_MAYBE();
411                 break;
412         /*
413          * We should be handling all known exception types above,
414          * if we get here we hit a reserved one, so panic
415          */
416         default:
417                 info.si_code = ILL_ILLPARAOP;
418                 sig = SIGILL;
419                 verbose_printk(KERN_EMERG "Caught Unhandled Exception, code = %08lx\n",
420                         (fp->seqstat & SEQSTAT_EXCAUSE));
421                 CHK_DEBUGGER_TRAP_MAYBE();
422                 break;
423         }
424
425         BUG_ON(sig == 0);
426
427         /* If the fault was caused by a kernel thread, or interrupt handler
428          * we will kernel panic, so the system reboots.
429          */
430         if (kernel_mode_regs(fp) || (current && !current->mm)) {
431                 console_verbose();
432                 oops_in_progress = 1;
433         }
434
435         if (sig != SIGTRAP) {
436                 if (strerror)
437                         verbose_printk(strerror);
438
439                 dump_bfin_process(fp);
440                 dump_bfin_mem(fp);
441                 show_regs(fp);
442
443                 /* Print out the trace buffer if it makes sense */
444 #ifndef CONFIG_DEBUG_BFIN_NO_KERN_HWTRACE
445                 if (trapnr == VEC_CPLB_I_M || trapnr == VEC_CPLB_M)
446                         verbose_printk(KERN_NOTICE "No trace since you do not have "
447                                "CONFIG_DEBUG_BFIN_NO_KERN_HWTRACE enabled\n\n");
448                 else
449 #endif
450                         dump_bfin_trace_buffer();
451
452                 if (oops_in_progress) {
453                         /* Dump the current kernel stack */
454                         verbose_printk(KERN_NOTICE "Kernel Stack\n");
455                         show_stack(current, NULL);
456                         print_modules();
457 #ifndef CONFIG_ACCESS_CHECK
458                         verbose_printk(KERN_EMERG "Please turn on "
459                                "CONFIG_ACCESS_CHECK\n");
460 #endif
461                         panic("Kernel exception");
462                 } else {
463 #ifdef CONFIG_DEBUG_VERBOSE
464                         unsigned long *stack;
465                         /* Dump the user space stack */
466                         stack = (unsigned long *)rdusp();
467                         verbose_printk(KERN_NOTICE "Userspace Stack\n");
468                         show_stack(NULL, stack);
469 #endif
470                 }
471         }
472
473 #ifdef CONFIG_IPIPE
474         if (!ipipe_trap_notify(fp->seqstat & 0x3f, fp))
475 #endif
476         {
477                 info.si_signo = sig;
478                 info.si_errno = 0;
479                 switch (trapnr) {
480                 case VEC_CPLB_VL:
481                 case VEC_MISALI_D:
482                 case VEC_CPLB_M:
483                 case VEC_CPLB_MHIT:
484                         info.si_addr = (void __user *)cpu_pda[cpu].dcplb_fault_addr;
485                         break;
486                 default:
487                         info.si_addr = (void __user *)fp->pc;
488                         break;
489                 }
490                 force_sig_info(sig, &info, current);
491         }
492
493         if ((ANOMALY_05000461 && trapnr == VEC_HWERR && !access_ok(VERIFY_READ, fp->pc, 8)) ||
494             (ANOMALY_05000281 && trapnr == VEC_HWERR) ||
495             (ANOMALY_05000189 && (trapnr == VEC_CPLB_I_VL || trapnr == VEC_CPLB_VL)))
496                 fp->pc = SAFE_USER_INSTRUCTION;
497
498  traps_done:
499         trace_buffer_restore(j);
500 }
501
502 asmlinkage void double_fault_c(struct pt_regs *fp)
503 {
504 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
505         int j;
506         trace_buffer_save(j);
507 #endif
508
509         console_verbose();
510         oops_in_progress = 1;
511 #ifdef CONFIG_DEBUG_VERBOSE
512         printk(KERN_EMERG "Double Fault\n");
513 #ifdef CONFIG_DEBUG_DOUBLEFAULT_PRINT
514         if (((long)fp->seqstat &  SEQSTAT_EXCAUSE) == VEC_UNCOV) {
515                 unsigned int cpu = raw_smp_processor_id();
516                 char buf[150];
517                 decode_address(buf, cpu_pda[cpu].retx_doublefault);
518                 printk(KERN_EMERG "While handling exception (EXCAUSE = 0x%x) at %s:\n",
519                         (unsigned int)cpu_pda[cpu].seqstat_doublefault & SEQSTAT_EXCAUSE, buf);
520                 decode_address(buf, cpu_pda[cpu].dcplb_doublefault_addr);
521                 printk(KERN_NOTICE "   DCPLB_FAULT_ADDR: %s\n", buf);
522                 decode_address(buf, cpu_pda[cpu].icplb_doublefault_addr);
523                 printk(KERN_NOTICE "   ICPLB_FAULT_ADDR: %s\n", buf);
524
525                 decode_address(buf, fp->retx);
526                 printk(KERN_NOTICE "The instruction at %s caused a double exception\n", buf);
527         } else
528 #endif
529         {
530                 dump_bfin_process(fp);
531                 dump_bfin_mem(fp);
532                 show_regs(fp);
533                 dump_bfin_trace_buffer();
534         }
535 #endif
536         panic("Double Fault - unrecoverable event");
537
538 }
539
540
541 void panic_cplb_error(int cplb_panic, struct pt_regs *fp)
542 {
543         switch (cplb_panic) {
544         case CPLB_NO_UNLOCKED:
545                 printk(KERN_EMERG "All CPLBs are locked\n");
546                 break;
547         case CPLB_PROT_VIOL:
548                 return;
549         case CPLB_NO_ADDR_MATCH:
550                 return;
551         case CPLB_UNKNOWN_ERR:
552                 printk(KERN_EMERG "Unknown CPLB Exception\n");
553                 break;
554         }
555
556         oops_in_progress = 1;
557
558         dump_bfin_process(fp);
559         dump_bfin_mem(fp);
560         show_regs(fp);
561         dump_stack();
562         panic("Unrecoverable event");
563 }
564
565 #ifdef CONFIG_BUG
566 int is_valid_bugaddr(unsigned long addr)
567 {
568         unsigned int opcode;
569
570         if (!get_instruction(&opcode, (unsigned short *)addr))
571                 return 0;
572
573         return opcode == BFIN_BUG_OPCODE;
574 }
575 #endif
576
577 /* stub this out */
578 #ifndef CONFIG_DEBUG_VERBOSE
579 void show_regs(struct pt_regs *fp)
580 {
581
582 }
583 #endif