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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> |
5a0015d6 CZ |
33 | |
34 | #include <asm/ptrace.h> | |
35 | #include <asm/timex.h> | |
36 | #include <asm/uaccess.h> | |
37 | #include <asm/pgtable.h> | |
38 | #include <asm/processor.h> | |
39 | ||
40 | #ifdef CONFIG_KGDB | |
41 | extern int gdb_enter; | |
42 | extern int return_from_debug_flag; | |
43 | #endif | |
44 | ||
45 | /* | |
46 | * Machine specific interrupt handlers | |
47 | */ | |
48 | ||
49 | extern void kernel_exception(void); | |
50 | extern void user_exception(void); | |
51 | ||
52 | extern void fast_syscall_kernel(void); | |
53 | extern void fast_syscall_user(void); | |
54 | extern void fast_alloca(void); | |
55 | extern void fast_unaligned(void); | |
56 | extern void fast_second_level_miss(void); | |
57 | extern void fast_store_prohibited(void); | |
58 | extern void fast_coprocessor(void); | |
59 | ||
60 | extern void do_illegal_instruction (struct pt_regs*); | |
61 | extern void do_interrupt (struct pt_regs*); | |
62 | extern void do_unaligned_user (struct pt_regs*); | |
63 | extern void do_multihit (struct pt_regs*, unsigned long); | |
64 | extern void do_page_fault (struct pt_regs*, unsigned long); | |
65 | extern void do_debug (struct pt_regs*); | |
66 | extern void system_call (struct pt_regs*); | |
67 | ||
68 | /* | |
69 | * The vector table must be preceded by a save area (which | |
70 | * implies it must be in RAM, unless one places RAM immediately | |
71 | * before a ROM and puts the vector at the start of the ROM (!)) | |
72 | */ | |
73 | ||
74 | #define KRNL 0x01 | |
75 | #define USER 0x02 | |
76 | ||
77 | #define COPROCESSOR(x) \ | |
78 | { XCHAL_EXCCAUSE_COPROCESSOR ## x ## _DISABLED, USER, fast_coprocessor } | |
79 | ||
80 | typedef struct { | |
81 | int cause; | |
82 | int fast; | |
83 | void* handler; | |
84 | } dispatch_init_table_t; | |
85 | ||
86 | dispatch_init_table_t __init dispatch_init_table[] = { | |
87 | ||
88 | { XCHAL_EXCCAUSE_ILLEGAL_INSTRUCTION, 0, do_illegal_instruction}, | |
89 | { XCHAL_EXCCAUSE_SYSTEM_CALL, KRNL, fast_syscall_kernel }, | |
90 | { XCHAL_EXCCAUSE_SYSTEM_CALL, USER, fast_syscall_user }, | |
91 | { XCHAL_EXCCAUSE_SYSTEM_CALL, 0, system_call }, | |
92 | /* XCHAL_EXCCAUSE_INSTRUCTION_FETCH unhandled */ | |
93 | /* XCHAL_EXCCAUSE_LOAD_STORE_ERROR unhandled*/ | |
94 | { XCHAL_EXCCAUSE_LEVEL1_INTERRUPT, 0, do_interrupt }, | |
95 | { XCHAL_EXCCAUSE_ALLOCA, USER|KRNL, fast_alloca }, | |
96 | /* XCHAL_EXCCAUSE_INTEGER_DIVIDE_BY_ZERO unhandled */ | |
97 | /* XCHAL_EXCCAUSE_PRIVILEGED unhandled */ | |
98 | #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION | |
99 | #ifdef CONFIG_UNALIGNED_USER | |
100 | { XCHAL_EXCCAUSE_UNALIGNED, USER, fast_unaligned }, | |
101 | #else | |
102 | { XCHAL_EXCCAUSE_UNALIGNED, 0, do_unaligned_user }, | |
103 | #endif | |
104 | { XCHAL_EXCCAUSE_UNALIGNED, KRNL, fast_unaligned }, | |
105 | #endif | |
106 | { XCHAL_EXCCAUSE_ITLB_MISS, 0, do_page_fault }, | |
107 | { XCHAL_EXCCAUSE_ITLB_MISS, USER|KRNL, fast_second_level_miss}, | |
108 | { XCHAL_EXCCAUSE_ITLB_MULTIHIT, 0, do_multihit }, | |
109 | { XCHAL_EXCCAUSE_ITLB_PRIVILEGE, 0, do_page_fault }, | |
110 | /* XCHAL_EXCCAUSE_SIZE_RESTRICTION unhandled */ | |
111 | { XCHAL_EXCCAUSE_FETCH_CACHE_ATTRIBUTE, 0, do_page_fault }, | |
112 | { XCHAL_EXCCAUSE_DTLB_MISS, USER|KRNL, fast_second_level_miss}, | |
113 | { XCHAL_EXCCAUSE_DTLB_MISS, 0, do_page_fault }, | |
114 | { XCHAL_EXCCAUSE_DTLB_MULTIHIT, 0, do_multihit }, | |
115 | { XCHAL_EXCCAUSE_DTLB_PRIVILEGE, 0, do_page_fault }, | |
116 | /* XCHAL_EXCCAUSE_DTLB_SIZE_RESTRICTION unhandled */ | |
117 | { XCHAL_EXCCAUSE_STORE_CACHE_ATTRIBUTE, USER|KRNL, fast_store_prohibited }, | |
118 | { XCHAL_EXCCAUSE_STORE_CACHE_ATTRIBUTE, 0, do_page_fault }, | |
119 | { XCHAL_EXCCAUSE_LOAD_CACHE_ATTRIBUTE, 0, do_page_fault }, | |
120 | /* XCCHAL_EXCCAUSE_FLOATING_POINT unhandled */ | |
121 | #if (XCHAL_CP_MASK & 1) | |
122 | COPROCESSOR(0), | |
123 | #endif | |
124 | #if (XCHAL_CP_MASK & 2) | |
125 | COPROCESSOR(1), | |
126 | #endif | |
127 | #if (XCHAL_CP_MASK & 4) | |
128 | COPROCESSOR(2), | |
129 | #endif | |
130 | #if (XCHAL_CP_MASK & 8) | |
131 | COPROCESSOR(3), | |
132 | #endif | |
133 | #if (XCHAL_CP_MASK & 16) | |
134 | COPROCESSOR(4), | |
135 | #endif | |
136 | #if (XCHAL_CP_MASK & 32) | |
137 | COPROCESSOR(5), | |
138 | #endif | |
139 | #if (XCHAL_CP_MASK & 64) | |
140 | COPROCESSOR(6), | |
141 | #endif | |
142 | #if (XCHAL_CP_MASK & 128) | |
143 | COPROCESSOR(7), | |
144 | #endif | |
145 | { EXCCAUSE_MAPPED_DEBUG, 0, do_debug }, | |
146 | { -1, -1, 0 } | |
147 | ||
148 | }; | |
149 | ||
150 | /* The exception table <exc_table> serves two functions: | |
151 | * 1. it contains three dispatch tables (fast_user, fast_kernel, default-c) | |
152 | * 2. it is a temporary memory buffer for the exception handlers. | |
153 | */ | |
154 | ||
155 | unsigned long exc_table[EXC_TABLE_SIZE/4]; | |
156 | ||
157 | void die(const char*, struct pt_regs*, long); | |
158 | ||
159 | static inline void | |
160 | __die_if_kernel(const char *str, struct pt_regs *regs, long err) | |
161 | { | |
162 | if (!user_mode(regs)) | |
163 | die(str, regs, err); | |
164 | } | |
165 | ||
166 | /* | |
167 | * Unhandled Exceptions. Kill user task or panic if in kernel space. | |
168 | */ | |
169 | ||
170 | void do_unhandled(struct pt_regs *regs, unsigned long exccause) | |
171 | { | |
172 | __die_if_kernel("Caught unhandled exception - should not happen", | |
173 | regs, SIGKILL); | |
174 | ||
175 | /* If in user mode, send SIGILL signal to current process */ | |
176 | printk("Caught unhandled exception in '%s' " | |
177 | "(pid = %d, pc = %#010lx) - should not happen\n" | |
178 | "\tEXCCAUSE is %ld\n", | |
179 | current->comm, current->pid, regs->pc, exccause); | |
180 | force_sig(SIGILL, current); | |
181 | } | |
182 | ||
183 | /* | |
184 | * Multi-hit exception. This if fatal! | |
185 | */ | |
186 | ||
187 | void do_multihit(struct pt_regs *regs, unsigned long exccause) | |
188 | { | |
189 | die("Caught multihit exception", regs, SIGKILL); | |
190 | } | |
191 | ||
192 | /* | |
193 | * Level-1 interrupt. | |
194 | * We currently have no priority encoding. | |
195 | */ | |
196 | ||
197 | unsigned long ignored_level1_interrupts; | |
198 | extern void do_IRQ(int, struct pt_regs *); | |
199 | ||
200 | void do_interrupt (struct pt_regs *regs) | |
201 | { | |
202 | unsigned long intread = get_sr (INTREAD); | |
203 | unsigned long intenable = get_sr (INTENABLE); | |
204 | int i, mask; | |
205 | ||
206 | /* Handle all interrupts (no priorities). | |
207 | * (Clear the interrupt before processing, in case it's | |
208 | * edge-triggered or software-generated) | |
209 | */ | |
210 | ||
211 | for (i=0, mask = 1; i < XCHAL_NUM_INTERRUPTS; i++, mask <<= 1) { | |
212 | if (mask & (intread & intenable)) { | |
213 | set_sr (mask, INTCLEAR); | |
214 | do_IRQ (i,regs); | |
215 | } | |
216 | } | |
217 | } | |
218 | ||
219 | /* | |
220 | * Illegal instruction. Fatal if in kernel space. | |
221 | */ | |
222 | ||
223 | void | |
224 | do_illegal_instruction(struct pt_regs *regs) | |
225 | { | |
226 | __die_if_kernel("Illegal instruction in kernel", regs, SIGKILL); | |
227 | ||
228 | /* If in user mode, send SIGILL signal to current process. */ | |
229 | ||
230 | printk("Illegal Instruction in '%s' (pid = %d, pc = %#010lx)\n", | |
231 | current->comm, current->pid, regs->pc); | |
232 | force_sig(SIGILL, current); | |
233 | } | |
234 | ||
235 | ||
236 | /* | |
237 | * Handle unaligned memory accesses from user space. Kill task. | |
238 | * | |
239 | * If CONFIG_UNALIGNED_USER is not set, we don't allow unaligned memory | |
240 | * accesses causes from user space. | |
241 | */ | |
242 | ||
243 | #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION | |
244 | #ifndef CONFIG_UNALIGNED_USER | |
245 | void | |
246 | do_unaligned_user (struct pt_regs *regs) | |
247 | { | |
248 | siginfo_t info; | |
249 | ||
250 | __die_if_kernel("Unhandled unaligned exception in kernel", | |
251 | regs, SIGKILL); | |
252 | ||
253 | current->thread.bad_vaddr = regs->excvaddr; | |
254 | current->thread.error_code = -3; | |
255 | printk("Unaligned memory access to %08lx in '%s' " | |
256 | "(pid = %d, pc = %#010lx)\n", | |
257 | regs->excvaddr, current->comm, current->pid, regs->pc); | |
258 | info.si_signo = SIGBUS; | |
259 | info.si_errno = 0; | |
260 | info.si_code = BUS_ADRALN; | |
261 | info.si_addr = (void *) regs->excvaddr; | |
262 | force_sig_info(SIGSEGV, &info, current); | |
263 | ||
264 | } | |
265 | #endif | |
266 | #endif | |
267 | ||
268 | void | |
269 | do_debug(struct pt_regs *regs) | |
270 | { | |
271 | #ifdef CONFIG_KGDB | |
272 | /* If remote debugging is configured AND enabled, we give control to | |
273 | * kgdb. Otherwise, we fall through, perhaps giving control to the | |
274 | * native debugger. | |
275 | */ | |
276 | ||
277 | if (gdb_enter) { | |
278 | extern void gdb_handle_exception(struct pt_regs *); | |
279 | gdb_handle_exception(regs); | |
280 | return_from_debug_flag = 1; | |
281 | return; | |
282 | } | |
283 | #endif | |
284 | ||
285 | __die_if_kernel("Breakpoint in kernel", regs, SIGKILL); | |
286 | ||
287 | /* If in user mode, send SIGTRAP signal to current process */ | |
288 | ||
289 | force_sig(SIGTRAP, current); | |
290 | } | |
291 | ||
292 | ||
293 | /* | |
294 | * Initialize dispatch tables. | |
295 | * | |
296 | * The exception vectors are stored compressed the __init section in the | |
297 | * dispatch_init_table. This function initializes the following three tables | |
298 | * from that compressed table: | |
299 | * - fast user first dispatch table for user exceptions | |
300 | * - fast kernel first dispatch table for kernel exceptions | |
301 | * - default C-handler C-handler called by the default fast handler. | |
302 | * | |
303 | * See vectors.S for more details. | |
304 | */ | |
305 | ||
306 | #define set_handler(idx,handler) (exc_table[idx] = (unsigned long) (handler)) | |
307 | ||
308 | void trap_init(void) | |
309 | { | |
310 | int i; | |
311 | ||
312 | /* Setup default vectors. */ | |
313 | ||
314 | for(i = 0; i < 64; i++) { | |
315 | set_handler(EXC_TABLE_FAST_USER/4 + i, user_exception); | |
316 | set_handler(EXC_TABLE_FAST_KERNEL/4 + i, kernel_exception); | |
317 | set_handler(EXC_TABLE_DEFAULT/4 + i, do_unhandled); | |
318 | } | |
319 | ||
320 | /* Setup specific handlers. */ | |
321 | ||
322 | for(i = 0; dispatch_init_table[i].cause >= 0; i++) { | |
323 | ||
324 | int fast = dispatch_init_table[i].fast; | |
325 | int cause = dispatch_init_table[i].cause; | |
326 | void *handler = dispatch_init_table[i].handler; | |
327 | ||
328 | if (fast == 0) | |
329 | set_handler (EXC_TABLE_DEFAULT/4 + cause, handler); | |
330 | if (fast && fast & USER) | |
331 | set_handler (EXC_TABLE_FAST_USER/4 + cause, handler); | |
332 | if (fast && fast & KRNL) | |
333 | set_handler (EXC_TABLE_FAST_KERNEL/4 + cause, handler); | |
334 | } | |
335 | ||
336 | /* Initialize EXCSAVE_1 to hold the address of the exception table. */ | |
337 | ||
338 | i = (unsigned long)exc_table; | |
339 | __asm__ __volatile__("wsr %0, "__stringify(EXCSAVE_1)"\n" : : "a" (i)); | |
340 | } | |
341 | ||
342 | /* | |
343 | * This function dumps the current valid window frame and other base registers. | |
344 | */ | |
345 | ||
346 | void show_regs(struct pt_regs * regs) | |
347 | { | |
348 | int i, wmask; | |
349 | ||
350 | wmask = regs->wmask & ~1; | |
351 | ||
352 | for (i = 0; i < 32; i++) { | |
353 | if (wmask & (1 << (i / 4))) | |
354 | break; | |
355 | if ((i % 8) == 0) | |
356 | printk ("\n" KERN_INFO "a%02d: ", i); | |
357 | printk("%08lx ", regs->areg[i]); | |
358 | } | |
359 | printk("\n"); | |
360 | ||
361 | printk("pc: %08lx, ps: %08lx, depc: %08lx, excvaddr: %08lx\n", | |
362 | regs->pc, regs->ps, regs->depc, regs->excvaddr); | |
363 | printk("lbeg: %08lx, lend: %08lx lcount: %08lx, sar: %08lx\n", | |
364 | regs->lbeg, regs->lend, regs->lcount, regs->sar); | |
365 | if (user_mode(regs)) | |
366 | printk("wb: %08lx, ws: %08lx, wmask: %08lx, syscall: %ld\n", | |
367 | regs->windowbase, regs->windowstart, regs->wmask, | |
368 | regs->syscall); | |
369 | } | |
370 | ||
371 | void show_trace(struct task_struct *task, unsigned long *sp) | |
372 | { | |
373 | unsigned long a0, a1, pc; | |
374 | unsigned long sp_start, sp_end; | |
375 | ||
376 | a1 = (unsigned long)sp; | |
377 | ||
378 | if (a1 == 0) | |
379 | __asm__ __volatile__ ("mov %0, a1\n" : "=a"(a1)); | |
380 | ||
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 | ||
422 | if (sp == 0) | |
423 | __asm__ __volatile__ ("mov %0, a1\n" : "=a"(sp)); | |
424 | ||
425 | stack = sp; | |
426 | ||
427 | printk("\nStack: "); | |
428 | ||
429 | for (i = 0; i < kstack_depth_to_print; i++) { | |
430 | if (kstack_end(sp)) | |
431 | break; | |
432 | if (i && ((i % 8) == 0)) | |
433 | printk("\n "); | |
434 | printk("%08lx ", *sp++); | |
435 | } | |
436 | printk("\n"); | |
437 | show_trace(task, stack); | |
438 | } | |
439 | ||
440 | void dump_stack(void) | |
441 | { | |
442 | show_stack(current, NULL); | |
443 | } | |
444 | ||
445 | EXPORT_SYMBOL(dump_stack); | |
446 | ||
447 | ||
448 | void show_code(unsigned int *pc) | |
449 | { | |
450 | long i; | |
451 | ||
452 | printk("\nCode:"); | |
453 | ||
454 | for(i = -3 ; i < 6 ; i++) { | |
455 | unsigned long insn; | |
456 | if (__get_user(insn, pc + i)) { | |
457 | printk(" (Bad address in pc)\n"); | |
458 | break; | |
459 | } | |
460 | printk("%c%08lx%c",(i?' ':'<'),insn,(i?' ':'>')); | |
461 | } | |
462 | } | |
463 | ||
34af946a | 464 | DEFINE_SPINLOCK(die_lock); |
5a0015d6 CZ |
465 | |
466 | void die(const char * str, struct pt_regs * regs, long err) | |
467 | { | |
468 | static int die_counter; | |
469 | int nl = 0; | |
470 | ||
471 | console_verbose(); | |
472 | spin_lock_irq(&die_lock); | |
473 | ||
474 | printk("%s: sig: %ld [#%d]\n", str, err, ++die_counter); | |
475 | #ifdef CONFIG_PREEMPT | |
476 | printk("PREEMPT "); | |
477 | nl = 1; | |
478 | #endif | |
479 | if (nl) | |
480 | printk("\n"); | |
481 | show_regs(regs); | |
482 | if (!user_mode(regs)) | |
483 | show_stack(NULL, (unsigned long*)regs->areg[1]); | |
484 | ||
485 | spin_unlock_irq(&die_lock); | |
486 | ||
487 | if (in_interrupt()) | |
488 | panic("Fatal exception in interrupt"); | |
489 | ||
cea6a4ba H |
490 | if (panic_on_oops) |
491 | panic("Fatal exception: panic_on_oops"); | |
492 | ||
5a0015d6 CZ |
493 | do_exit(err); |
494 | } | |
495 | ||
496 |