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5a0015d6 CZ |
1 | /* |
2 | * arch/xtensa/kernel/traps.c | |
3 | * | |
4 | * Exception handling. | |
5 | * | |
6 | * Derived from code with the following copyrights: | |
7 | * Copyright (C) 1994 - 1999 by Ralf Baechle | |
8 | * Modified for R3000 by Paul M. Antoine, 1995, 1996 | |
9 | * Complete output from die() by Ulf Carlsson, 1998 | |
10 | * Copyright (C) 1999 Silicon Graphics, Inc. | |
11 | * | |
12 | * Essentially rewritten for the Xtensa architecture port. | |
13 | * | |
14 | * Copyright (C) 2001 - 2005 Tensilica Inc. | |
15 | * | |
16 | * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com> | |
17 | * Chris Zankel <chris@zankel.net> | |
18 | * Marc Gauthier<marc@tensilica.com, marc@alumni.uwaterloo.ca> | |
19 | * Kevin Chea | |
20 | * | |
21 | * This file is subject to the terms and conditions of the GNU General Public | |
22 | * License. See the file "COPYING" in the main directory of this archive | |
23 | * for more details. | |
24 | */ | |
25 | ||
26 | #include <linux/kernel.h> | |
27 | #include <linux/sched.h> | |
28 | #include <linux/init.h> | |
29 | #include <linux/module.h> | |
30 | #include <linux/stringify.h> | |
31 | #include <linux/kallsyms.h> | |
5c888d53 | 32 | #include <linux/delay.h> |
5a891ed5 | 33 | #include <linux/hardirq.h> |
5a0015d6 CZ |
34 | |
35 | #include <asm/ptrace.h> | |
36 | #include <asm/timex.h> | |
37 | #include <asm/uaccess.h> | |
38 | #include <asm/pgtable.h> | |
39 | #include <asm/processor.h> | |
40 | ||
41 | #ifdef CONFIG_KGDB | |
42 | extern int gdb_enter; | |
43 | extern int return_from_debug_flag; | |
44 | #endif | |
45 | ||
46 | /* | |
47 | * Machine specific interrupt handlers | |
48 | */ | |
49 | ||
50 | extern void kernel_exception(void); | |
51 | extern void user_exception(void); | |
52 | ||
53 | extern void fast_syscall_kernel(void); | |
54 | extern void fast_syscall_user(void); | |
55 | extern void fast_alloca(void); | |
56 | extern void fast_unaligned(void); | |
57 | extern void fast_second_level_miss(void); | |
58 | extern void fast_store_prohibited(void); | |
59 | extern void fast_coprocessor(void); | |
60 | ||
61 | extern void do_illegal_instruction (struct pt_regs*); | |
62 | extern void do_interrupt (struct pt_regs*); | |
63 | extern void do_unaligned_user (struct pt_regs*); | |
64 | extern void do_multihit (struct pt_regs*, unsigned long); | |
65 | extern void do_page_fault (struct pt_regs*, unsigned long); | |
66 | extern void do_debug (struct pt_regs*); | |
67 | extern void system_call (struct pt_regs*); | |
68 | ||
69 | /* | |
70 | * The vector table must be preceded by a save area (which | |
71 | * implies it must be in RAM, unless one places RAM immediately | |
72 | * before a ROM and puts the vector at the start of the ROM (!)) | |
73 | */ | |
74 | ||
75 | #define KRNL 0x01 | |
76 | #define USER 0x02 | |
77 | ||
78 | #define COPROCESSOR(x) \ | |
173d6681 | 79 | { EXCCAUSE_COPROCESSOR ## x ## _DISABLED, USER, fast_coprocessor } |
5a0015d6 CZ |
80 | |
81 | typedef struct { | |
82 | int cause; | |
83 | int fast; | |
84 | void* handler; | |
85 | } dispatch_init_table_t; | |
86 | ||
b91dc336 | 87 | static dispatch_init_table_t __initdata dispatch_init_table[] = { |
5a0015d6 | 88 | |
173d6681 CZ |
89 | { EXCCAUSE_ILLEGAL_INSTRUCTION, 0, do_illegal_instruction}, |
90 | { EXCCAUSE_SYSTEM_CALL, KRNL, fast_syscall_kernel }, | |
91 | { EXCCAUSE_SYSTEM_CALL, USER, fast_syscall_user }, | |
92 | { EXCCAUSE_SYSTEM_CALL, 0, system_call }, | |
93 | /* EXCCAUSE_INSTRUCTION_FETCH unhandled */ | |
94 | /* EXCCAUSE_LOAD_STORE_ERROR unhandled*/ | |
95 | { EXCCAUSE_LEVEL1_INTERRUPT, 0, do_interrupt }, | |
96 | { EXCCAUSE_ALLOCA, USER|KRNL, fast_alloca }, | |
97 | /* EXCCAUSE_INTEGER_DIVIDE_BY_ZERO unhandled */ | |
98 | /* EXCCAUSE_PRIVILEGED unhandled */ | |
5a0015d6 CZ |
99 | #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION |
100 | #ifdef CONFIG_UNALIGNED_USER | |
173d6681 | 101 | { EXCCAUSE_UNALIGNED, USER, fast_unaligned }, |
5a0015d6 | 102 | #else |
173d6681 | 103 | { EXCCAUSE_UNALIGNED, 0, do_unaligned_user }, |
5a0015d6 | 104 | #endif |
173d6681 | 105 | { EXCCAUSE_UNALIGNED, KRNL, fast_unaligned }, |
5a0015d6 | 106 | #endif |
e5083a63 | 107 | #ifdef CONFIG_MMU |
173d6681 CZ |
108 | { EXCCAUSE_ITLB_MISS, 0, do_page_fault }, |
109 | { EXCCAUSE_ITLB_MISS, USER|KRNL, fast_second_level_miss}, | |
110 | { EXCCAUSE_ITLB_MULTIHIT, 0, do_multihit }, | |
111 | { EXCCAUSE_ITLB_PRIVILEGE, 0, do_page_fault }, | |
112 | /* EXCCAUSE_SIZE_RESTRICTION unhandled */ | |
113 | { EXCCAUSE_FETCH_CACHE_ATTRIBUTE, 0, do_page_fault }, | |
114 | { EXCCAUSE_DTLB_MISS, USER|KRNL, fast_second_level_miss}, | |
115 | { EXCCAUSE_DTLB_MISS, 0, do_page_fault }, | |
116 | { EXCCAUSE_DTLB_MULTIHIT, 0, do_multihit }, | |
117 | { EXCCAUSE_DTLB_PRIVILEGE, 0, do_page_fault }, | |
118 | /* EXCCAUSE_DTLB_SIZE_RESTRICTION unhandled */ | |
119 | { EXCCAUSE_STORE_CACHE_ATTRIBUTE, USER|KRNL, fast_store_prohibited }, | |
120 | { EXCCAUSE_STORE_CACHE_ATTRIBUTE, 0, do_page_fault }, | |
121 | { EXCCAUSE_LOAD_CACHE_ATTRIBUTE, 0, do_page_fault }, | |
e5083a63 | 122 | #endif /* CONFIG_MMU */ |
5a0015d6 | 123 | /* XCCHAL_EXCCAUSE_FLOATING_POINT unhandled */ |
c658eac6 | 124 | #if XTENSA_HAVE_COPROCESSOR(0) |
5a0015d6 CZ |
125 | COPROCESSOR(0), |
126 | #endif | |
c658eac6 | 127 | #if XTENSA_HAVE_COPROCESSOR(1) |
5a0015d6 CZ |
128 | COPROCESSOR(1), |
129 | #endif | |
c658eac6 | 130 | #if XTENSA_HAVE_COPROCESSOR(2) |
5a0015d6 CZ |
131 | COPROCESSOR(2), |
132 | #endif | |
c658eac6 | 133 | #if XTENSA_HAVE_COPROCESSOR(3) |
5a0015d6 CZ |
134 | COPROCESSOR(3), |
135 | #endif | |
c658eac6 | 136 | #if XTENSA_HAVE_COPROCESSOR(4) |
5a0015d6 CZ |
137 | COPROCESSOR(4), |
138 | #endif | |
c658eac6 | 139 | #if XTENSA_HAVE_COPROCESSOR(5) |
5a0015d6 CZ |
140 | COPROCESSOR(5), |
141 | #endif | |
c658eac6 | 142 | #if XTENSA_HAVE_COPROCESSOR(6) |
5a0015d6 CZ |
143 | COPROCESSOR(6), |
144 | #endif | |
c658eac6 | 145 | #if XTENSA_HAVE_COPROCESSOR(7) |
5a0015d6 CZ |
146 | COPROCESSOR(7), |
147 | #endif | |
148 | { EXCCAUSE_MAPPED_DEBUG, 0, do_debug }, | |
149 | { -1, -1, 0 } | |
150 | ||
151 | }; | |
152 | ||
153 | /* The exception table <exc_table> serves two functions: | |
154 | * 1. it contains three dispatch tables (fast_user, fast_kernel, default-c) | |
155 | * 2. it is a temporary memory buffer for the exception handlers. | |
156 | */ | |
157 | ||
158 | unsigned long exc_table[EXC_TABLE_SIZE/4]; | |
159 | ||
160 | void die(const char*, struct pt_regs*, long); | |
161 | ||
162 | static inline void | |
163 | __die_if_kernel(const char *str, struct pt_regs *regs, long err) | |
164 | { | |
165 | if (!user_mode(regs)) | |
166 | die(str, regs, err); | |
167 | } | |
168 | ||
169 | /* | |
170 | * Unhandled Exceptions. Kill user task or panic if in kernel space. | |
171 | */ | |
172 | ||
173 | void do_unhandled(struct pt_regs *regs, unsigned long exccause) | |
174 | { | |
175 | __die_if_kernel("Caught unhandled exception - should not happen", | |
176 | regs, SIGKILL); | |
177 | ||
178 | /* If in user mode, send SIGILL signal to current process */ | |
179 | printk("Caught unhandled exception in '%s' " | |
180 | "(pid = %d, pc = %#010lx) - should not happen\n" | |
181 | "\tEXCCAUSE is %ld\n", | |
19c5870c | 182 | current->comm, task_pid_nr(current), regs->pc, exccause); |
5a0015d6 CZ |
183 | force_sig(SIGILL, current); |
184 | } | |
185 | ||
186 | /* | |
187 | * Multi-hit exception. This if fatal! | |
188 | */ | |
189 | ||
190 | void do_multihit(struct pt_regs *regs, unsigned long exccause) | |
191 | { | |
192 | die("Caught multihit exception", regs, SIGKILL); | |
193 | } | |
194 | ||
195 | /* | |
196 | * Level-1 interrupt. | |
197 | * We currently have no priority encoding. | |
198 | */ | |
199 | ||
200 | unsigned long ignored_level1_interrupts; | |
201 | extern void do_IRQ(int, struct pt_regs *); | |
202 | ||
203 | void do_interrupt (struct pt_regs *regs) | |
204 | { | |
205 | unsigned long intread = get_sr (INTREAD); | |
206 | unsigned long intenable = get_sr (INTENABLE); | |
207 | int i, mask; | |
208 | ||
209 | /* Handle all interrupts (no priorities). | |
210 | * (Clear the interrupt before processing, in case it's | |
211 | * edge-triggered or software-generated) | |
212 | */ | |
213 | ||
214 | for (i=0, mask = 1; i < XCHAL_NUM_INTERRUPTS; i++, mask <<= 1) { | |
215 | if (mask & (intread & intenable)) { | |
216 | set_sr (mask, INTCLEAR); | |
217 | do_IRQ (i,regs); | |
218 | } | |
219 | } | |
220 | } | |
221 | ||
222 | /* | |
223 | * Illegal instruction. Fatal if in kernel space. | |
224 | */ | |
225 | ||
226 | void | |
227 | do_illegal_instruction(struct pt_regs *regs) | |
228 | { | |
229 | __die_if_kernel("Illegal instruction in kernel", regs, SIGKILL); | |
230 | ||
231 | /* If in user mode, send SIGILL signal to current process. */ | |
232 | ||
233 | printk("Illegal Instruction in '%s' (pid = %d, pc = %#010lx)\n", | |
19c5870c | 234 | current->comm, task_pid_nr(current), regs->pc); |
5a0015d6 CZ |
235 | force_sig(SIGILL, current); |
236 | } | |
237 | ||
238 | ||
239 | /* | |
240 | * Handle unaligned memory accesses from user space. Kill task. | |
241 | * | |
242 | * If CONFIG_UNALIGNED_USER is not set, we don't allow unaligned memory | |
243 | * accesses causes from user space. | |
244 | */ | |
245 | ||
246 | #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION | |
247 | #ifndef CONFIG_UNALIGNED_USER | |
248 | void | |
249 | do_unaligned_user (struct pt_regs *regs) | |
250 | { | |
251 | siginfo_t info; | |
252 | ||
253 | __die_if_kernel("Unhandled unaligned exception in kernel", | |
254 | regs, SIGKILL); | |
255 | ||
256 | current->thread.bad_vaddr = regs->excvaddr; | |
257 | current->thread.error_code = -3; | |
258 | printk("Unaligned memory access to %08lx in '%s' " | |
259 | "(pid = %d, pc = %#010lx)\n", | |
19c5870c | 260 | regs->excvaddr, current->comm, task_pid_nr(current), regs->pc); |
5a0015d6 CZ |
261 | info.si_signo = SIGBUS; |
262 | info.si_errno = 0; | |
263 | info.si_code = BUS_ADRALN; | |
264 | info.si_addr = (void *) regs->excvaddr; | |
265 | force_sig_info(SIGSEGV, &info, current); | |
266 | ||
267 | } | |
268 | #endif | |
269 | #endif | |
270 | ||
271 | void | |
272 | do_debug(struct pt_regs *regs) | |
273 | { | |
274 | #ifdef CONFIG_KGDB | |
275 | /* If remote debugging is configured AND enabled, we give control to | |
276 | * kgdb. Otherwise, we fall through, perhaps giving control to the | |
277 | * native debugger. | |
278 | */ | |
279 | ||
280 | if (gdb_enter) { | |
281 | extern void gdb_handle_exception(struct pt_regs *); | |
282 | gdb_handle_exception(regs); | |
283 | return_from_debug_flag = 1; | |
284 | return; | |
285 | } | |
286 | #endif | |
287 | ||
288 | __die_if_kernel("Breakpoint in kernel", regs, SIGKILL); | |
289 | ||
290 | /* If in user mode, send SIGTRAP signal to current process */ | |
291 | ||
292 | force_sig(SIGTRAP, current); | |
293 | } | |
294 | ||
295 | ||
296 | /* | |
297 | * Initialize dispatch tables. | |
298 | * | |
299 | * The exception vectors are stored compressed the __init section in the | |
300 | * dispatch_init_table. This function initializes the following three tables | |
301 | * from that compressed table: | |
302 | * - fast user first dispatch table for user exceptions | |
303 | * - fast kernel first dispatch table for kernel exceptions | |
304 | * - default C-handler C-handler called by the default fast handler. | |
305 | * | |
306 | * See vectors.S for more details. | |
307 | */ | |
308 | ||
309 | #define set_handler(idx,handler) (exc_table[idx] = (unsigned long) (handler)) | |
310 | ||
b91dc336 | 311 | void __init trap_init(void) |
5a0015d6 CZ |
312 | { |
313 | int i; | |
314 | ||
315 | /* Setup default vectors. */ | |
316 | ||
317 | for(i = 0; i < 64; i++) { | |
318 | set_handler(EXC_TABLE_FAST_USER/4 + i, user_exception); | |
319 | set_handler(EXC_TABLE_FAST_KERNEL/4 + i, kernel_exception); | |
320 | set_handler(EXC_TABLE_DEFAULT/4 + i, do_unhandled); | |
321 | } | |
322 | ||
323 | /* Setup specific handlers. */ | |
324 | ||
325 | for(i = 0; dispatch_init_table[i].cause >= 0; i++) { | |
326 | ||
327 | int fast = dispatch_init_table[i].fast; | |
328 | int cause = dispatch_init_table[i].cause; | |
329 | void *handler = dispatch_init_table[i].handler; | |
330 | ||
331 | if (fast == 0) | |
332 | set_handler (EXC_TABLE_DEFAULT/4 + cause, handler); | |
333 | if (fast && fast & USER) | |
334 | set_handler (EXC_TABLE_FAST_USER/4 + cause, handler); | |
335 | if (fast && fast & KRNL) | |
336 | set_handler (EXC_TABLE_FAST_KERNEL/4 + cause, handler); | |
337 | } | |
338 | ||
339 | /* Initialize EXCSAVE_1 to hold the address of the exception table. */ | |
340 | ||
341 | i = (unsigned long)exc_table; | |
342 | __asm__ __volatile__("wsr %0, "__stringify(EXCSAVE_1)"\n" : : "a" (i)); | |
343 | } | |
344 | ||
345 | /* | |
346 | * This function dumps the current valid window frame and other base registers. | |
347 | */ | |
348 | ||
349 | void show_regs(struct pt_regs * regs) | |
350 | { | |
351 | int i, wmask; | |
352 | ||
353 | wmask = regs->wmask & ~1; | |
354 | ||
8d7e8240 | 355 | for (i = 0; i < 16; i++) { |
5a0015d6 CZ |
356 | if ((i % 8) == 0) |
357 | printk ("\n" KERN_INFO "a%02d: ", i); | |
358 | printk("%08lx ", regs->areg[i]); | |
359 | } | |
360 | printk("\n"); | |
361 | ||
362 | printk("pc: %08lx, ps: %08lx, depc: %08lx, excvaddr: %08lx\n", | |
363 | regs->pc, regs->ps, regs->depc, regs->excvaddr); | |
364 | printk("lbeg: %08lx, lend: %08lx lcount: %08lx, sar: %08lx\n", | |
365 | regs->lbeg, regs->lend, regs->lcount, regs->sar); | |
366 | if (user_mode(regs)) | |
367 | printk("wb: %08lx, ws: %08lx, wmask: %08lx, syscall: %ld\n", | |
368 | regs->windowbase, regs->windowstart, regs->wmask, | |
369 | regs->syscall); | |
370 | } | |
371 | ||
372 | void show_trace(struct task_struct *task, unsigned long *sp) | |
373 | { | |
374 | unsigned long a0, a1, pc; | |
375 | unsigned long sp_start, sp_end; | |
376 | ||
28a0ce7f JW |
377 | if (sp) |
378 | a1 = (unsigned long)sp; | |
379 | else | |
380 | a1 = task->thread.sp; | |
5a0015d6 CZ |
381 | |
382 | sp_start = a1 & ~(THREAD_SIZE-1); | |
383 | sp_end = sp_start + THREAD_SIZE; | |
384 | ||
385 | printk("Call Trace:"); | |
386 | #ifdef CONFIG_KALLSYMS | |
387 | printk("\n"); | |
388 | #endif | |
389 | spill_registers(); | |
390 | ||
391 | while (a1 > sp_start && a1 < sp_end) { | |
392 | sp = (unsigned long*)a1; | |
393 | ||
394 | a0 = *(sp - 4); | |
395 | a1 = *(sp - 3); | |
396 | ||
397 | if (a1 <= (unsigned long) sp) | |
398 | break; | |
399 | ||
400 | pc = MAKE_PC_FROM_RA(a0, a1); | |
401 | ||
402 | if (kernel_text_address(pc)) { | |
403 | printk(" [<%08lx>] ", pc); | |
404 | print_symbol("%s\n", pc); | |
405 | } | |
406 | } | |
407 | printk("\n"); | |
408 | } | |
409 | ||
410 | /* | |
411 | * This routine abuses get_user()/put_user() to reference pointers | |
412 | * with at least a bit of error checking ... | |
413 | */ | |
414 | ||
415 | static int kstack_depth_to_print = 24; | |
416 | ||
417 | void show_stack(struct task_struct *task, unsigned long *sp) | |
418 | { | |
419 | int i = 0; | |
420 | unsigned long *stack; | |
421 | ||
28a0ce7f JW |
422 | if (!sp) |
423 | sp = (unsigned long *)task->thread.sp; | |
5a0015d6 CZ |
424 | stack = sp; |
425 | ||
426 | printk("\nStack: "); | |
427 | ||
428 | for (i = 0; i < kstack_depth_to_print; i++) { | |
429 | if (kstack_end(sp)) | |
430 | break; | |
431 | if (i && ((i % 8) == 0)) | |
432 | printk("\n "); | |
433 | printk("%08lx ", *sp++); | |
434 | } | |
435 | printk("\n"); | |
436 | show_trace(task, stack); | |
437 | } | |
438 | ||
439 | void dump_stack(void) | |
440 | { | |
441 | show_stack(current, NULL); | |
442 | } | |
443 | ||
444 | EXPORT_SYMBOL(dump_stack); | |
445 | ||
446 | ||
447 | void show_code(unsigned int *pc) | |
448 | { | |
449 | long i; | |
450 | ||
451 | printk("\nCode:"); | |
452 | ||
453 | for(i = -3 ; i < 6 ; i++) { | |
454 | unsigned long insn; | |
455 | if (__get_user(insn, pc + i)) { | |
456 | printk(" (Bad address in pc)\n"); | |
457 | break; | |
458 | } | |
459 | printk("%c%08lx%c",(i?' ':'<'),insn,(i?' ':'>')); | |
460 | } | |
461 | } | |
462 | ||
34af946a | 463 | DEFINE_SPINLOCK(die_lock); |
5a0015d6 CZ |
464 | |
465 | void die(const char * str, struct pt_regs * regs, long err) | |
466 | { | |
467 | static int die_counter; | |
468 | int nl = 0; | |
469 | ||
470 | console_verbose(); | |
471 | spin_lock_irq(&die_lock); | |
472 | ||
473 | printk("%s: sig: %ld [#%d]\n", str, err, ++die_counter); | |
474 | #ifdef CONFIG_PREEMPT | |
475 | printk("PREEMPT "); | |
476 | nl = 1; | |
477 | #endif | |
478 | if (nl) | |
479 | printk("\n"); | |
480 | show_regs(regs); | |
481 | if (!user_mode(regs)) | |
482 | show_stack(NULL, (unsigned long*)regs->areg[1]); | |
483 | ||
bcdcd8e7 | 484 | add_taint(TAINT_DIE); |
5a0015d6 CZ |
485 | spin_unlock_irq(&die_lock); |
486 | ||
487 | if (in_interrupt()) | |
488 | panic("Fatal exception in interrupt"); | |
489 | ||
cea6a4ba | 490 | if (panic_on_oops) |
012c437d | 491 | panic("Fatal exception"); |
cea6a4ba | 492 | |
5a0015d6 CZ |
493 | do_exit(err); |
494 | } | |
495 | ||
496 |