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[linux/fpc-iii.git] / arch / xtensa / kernel / traps.c
blob9d2f45f010ef7e9448e3837e873b617f0a493b23
1 /*
2 * arch/xtensa/kernel/traps.c
4 * Exception handling.
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.
12 * Essentially rewritten for the Xtensa architecture port.
14 * Copyright (C) 2001 - 2013 Tensilica Inc.
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
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.
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>
32 #include <linux/delay.h>
33 #include <linux/hardirq.h>
35 #include <asm/stacktrace.h>
36 #include <asm/ptrace.h>
37 #include <asm/timex.h>
38 #include <asm/uaccess.h>
39 #include <asm/pgtable.h>
40 #include <asm/processor.h>
41 #include <asm/traps.h>
43 #ifdef CONFIG_KGDB
44 extern int gdb_enter;
45 extern int return_from_debug_flag;
46 #endif
49 * Machine specific interrupt handlers
52 extern void kernel_exception(void);
53 extern void user_exception(void);
55 extern void fast_syscall_kernel(void);
56 extern void fast_syscall_user(void);
57 extern void fast_alloca(void);
58 extern void fast_unaligned(void);
59 extern void fast_second_level_miss(void);
60 extern void fast_store_prohibited(void);
61 extern void fast_coprocessor(void);
63 extern void do_illegal_instruction (struct pt_regs*);
64 extern void do_interrupt (struct pt_regs*);
65 extern void do_unaligned_user (struct pt_regs*);
66 extern void do_multihit (struct pt_regs*, unsigned long);
67 extern void do_page_fault (struct pt_regs*, unsigned long);
68 extern void do_debug (struct pt_regs*);
69 extern void system_call (struct pt_regs*);
72 * The vector table must be preceded by a save area (which
73 * implies it must be in RAM, unless one places RAM immediately
74 * before a ROM and puts the vector at the start of the ROM (!))
77 #define KRNL 0x01
78 #define USER 0x02
80 #define COPROCESSOR(x) \
81 { EXCCAUSE_COPROCESSOR ## x ## _DISABLED, USER, fast_coprocessor }
83 typedef struct {
84 int cause;
85 int fast;
86 void* handler;
87 } dispatch_init_table_t;
89 static dispatch_init_table_t __initdata dispatch_init_table[] = {
91 { EXCCAUSE_ILLEGAL_INSTRUCTION, 0, do_illegal_instruction},
92 { EXCCAUSE_SYSTEM_CALL, KRNL, fast_syscall_kernel },
93 { EXCCAUSE_SYSTEM_CALL, USER, fast_syscall_user },
94 { EXCCAUSE_SYSTEM_CALL, 0, system_call },
95 /* EXCCAUSE_INSTRUCTION_FETCH unhandled */
96 /* EXCCAUSE_LOAD_STORE_ERROR unhandled*/
97 { EXCCAUSE_LEVEL1_INTERRUPT, 0, do_interrupt },
98 { EXCCAUSE_ALLOCA, USER|KRNL, fast_alloca },
99 /* EXCCAUSE_INTEGER_DIVIDE_BY_ZERO unhandled */
100 /* EXCCAUSE_PRIVILEGED unhandled */
101 #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION
102 #ifdef CONFIG_XTENSA_UNALIGNED_USER
103 { EXCCAUSE_UNALIGNED, USER, fast_unaligned },
104 #endif
105 { EXCCAUSE_UNALIGNED, 0, do_unaligned_user },
106 { EXCCAUSE_UNALIGNED, KRNL, fast_unaligned },
107 #endif
108 #ifdef CONFIG_MMU
109 { EXCCAUSE_ITLB_MISS, 0, do_page_fault },
110 { EXCCAUSE_ITLB_MISS, USER|KRNL, fast_second_level_miss},
111 { EXCCAUSE_ITLB_MULTIHIT, 0, do_multihit },
112 { EXCCAUSE_ITLB_PRIVILEGE, 0, do_page_fault },
113 /* EXCCAUSE_SIZE_RESTRICTION unhandled */
114 { EXCCAUSE_FETCH_CACHE_ATTRIBUTE, 0, do_page_fault },
115 { EXCCAUSE_DTLB_MISS, USER|KRNL, fast_second_level_miss},
116 { EXCCAUSE_DTLB_MISS, 0, do_page_fault },
117 { EXCCAUSE_DTLB_MULTIHIT, 0, do_multihit },
118 { EXCCAUSE_DTLB_PRIVILEGE, 0, do_page_fault },
119 /* EXCCAUSE_DTLB_SIZE_RESTRICTION unhandled */
120 { EXCCAUSE_STORE_CACHE_ATTRIBUTE, USER|KRNL, fast_store_prohibited },
121 { EXCCAUSE_STORE_CACHE_ATTRIBUTE, 0, do_page_fault },
122 { EXCCAUSE_LOAD_CACHE_ATTRIBUTE, 0, do_page_fault },
123 #endif /* CONFIG_MMU */
124 /* XCCHAL_EXCCAUSE_FLOATING_POINT unhandled */
125 #if XTENSA_HAVE_COPROCESSOR(0)
126 COPROCESSOR(0),
127 #endif
128 #if XTENSA_HAVE_COPROCESSOR(1)
129 COPROCESSOR(1),
130 #endif
131 #if XTENSA_HAVE_COPROCESSOR(2)
132 COPROCESSOR(2),
133 #endif
134 #if XTENSA_HAVE_COPROCESSOR(3)
135 COPROCESSOR(3),
136 #endif
137 #if XTENSA_HAVE_COPROCESSOR(4)
138 COPROCESSOR(4),
139 #endif
140 #if XTENSA_HAVE_COPROCESSOR(5)
141 COPROCESSOR(5),
142 #endif
143 #if XTENSA_HAVE_COPROCESSOR(6)
144 COPROCESSOR(6),
145 #endif
146 #if XTENSA_HAVE_COPROCESSOR(7)
147 COPROCESSOR(7),
148 #endif
149 { EXCCAUSE_MAPPED_DEBUG, 0, do_debug },
150 { -1, -1, 0 }
154 /* The exception table <exc_table> serves two functions:
155 * 1. it contains three dispatch tables (fast_user, fast_kernel, default-c)
156 * 2. it is a temporary memory buffer for the exception handlers.
159 DEFINE_PER_CPU(unsigned long, exc_table[EXC_TABLE_SIZE/4]);
161 void die(const char*, struct pt_regs*, long);
163 static inline void
164 __die_if_kernel(const char *str, struct pt_regs *regs, long err)
166 if (!user_mode(regs))
167 die(str, regs, err);
171 * Unhandled Exceptions. Kill user task or panic if in kernel space.
174 void do_unhandled(struct pt_regs *regs, unsigned long exccause)
176 __die_if_kernel("Caught unhandled exception - should not happen",
177 regs, SIGKILL);
179 /* If in user mode, send SIGILL signal to current process */
180 printk("Caught unhandled exception in '%s' "
181 "(pid = %d, pc = %#010lx) - should not happen\n"
182 "\tEXCCAUSE is %ld\n",
183 current->comm, task_pid_nr(current), regs->pc, exccause);
184 force_sig(SIGILL, current);
188 * Multi-hit exception. This if fatal!
191 void do_multihit(struct pt_regs *regs, unsigned long exccause)
193 die("Caught multihit exception", regs, SIGKILL);
197 * IRQ handler.
200 extern void do_IRQ(int, struct pt_regs *);
202 void do_interrupt(struct pt_regs *regs)
204 static const unsigned int_level_mask[] = {
206 XCHAL_INTLEVEL1_MASK,
207 XCHAL_INTLEVEL2_MASK,
208 XCHAL_INTLEVEL3_MASK,
209 XCHAL_INTLEVEL4_MASK,
210 XCHAL_INTLEVEL5_MASK,
211 XCHAL_INTLEVEL6_MASK,
212 XCHAL_INTLEVEL7_MASK,
214 struct pt_regs *old_regs = set_irq_regs(regs);
216 irq_enter();
218 for (;;) {
219 unsigned intread = get_sr(interrupt);
220 unsigned intenable = get_sr(intenable);
221 unsigned int_at_level = intread & intenable;
222 unsigned level;
224 for (level = LOCKLEVEL; level > 0; --level) {
225 if (int_at_level & int_level_mask[level]) {
226 int_at_level &= int_level_mask[level];
227 break;
231 if (level == 0)
232 break;
234 do_IRQ(__ffs(int_at_level), regs);
237 irq_exit();
238 set_irq_regs(old_regs);
242 * Illegal instruction. Fatal if in kernel space.
245 void
246 do_illegal_instruction(struct pt_regs *regs)
248 __die_if_kernel("Illegal instruction in kernel", regs, SIGKILL);
250 /* If in user mode, send SIGILL signal to current process. */
252 printk("Illegal Instruction in '%s' (pid = %d, pc = %#010lx)\n",
253 current->comm, task_pid_nr(current), regs->pc);
254 force_sig(SIGILL, current);
259 * Handle unaligned memory accesses from user space. Kill task.
261 * If CONFIG_UNALIGNED_USER is not set, we don't allow unaligned memory
262 * accesses causes from user space.
265 #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION
266 void
267 do_unaligned_user (struct pt_regs *regs)
269 siginfo_t info;
271 __die_if_kernel("Unhandled unaligned exception in kernel",
272 regs, SIGKILL);
274 current->thread.bad_vaddr = regs->excvaddr;
275 current->thread.error_code = -3;
276 printk("Unaligned memory access to %08lx in '%s' "
277 "(pid = %d, pc = %#010lx)\n",
278 regs->excvaddr, current->comm, task_pid_nr(current), regs->pc);
279 info.si_signo = SIGBUS;
280 info.si_errno = 0;
281 info.si_code = BUS_ADRALN;
282 info.si_addr = (void *) regs->excvaddr;
283 force_sig_info(SIGSEGV, &info, current);
286 #endif
288 void
289 do_debug(struct pt_regs *regs)
291 #ifdef CONFIG_KGDB
292 /* If remote debugging is configured AND enabled, we give control to
293 * kgdb. Otherwise, we fall through, perhaps giving control to the
294 * native debugger.
297 if (gdb_enter) {
298 extern void gdb_handle_exception(struct pt_regs *);
299 gdb_handle_exception(regs);
300 return_from_debug_flag = 1;
301 return;
303 #endif
305 __die_if_kernel("Breakpoint in kernel", regs, SIGKILL);
307 /* If in user mode, send SIGTRAP signal to current process */
309 force_sig(SIGTRAP, current);
313 static void set_handler(int idx, void *handler)
315 unsigned int cpu;
317 for_each_possible_cpu(cpu)
318 per_cpu(exc_table, cpu)[idx] = (unsigned long)handler;
321 /* Set exception C handler - for temporary use when probing exceptions */
323 void * __init trap_set_handler(int cause, void *handler)
325 void *previous = (void *)per_cpu(exc_table, 0)[
326 EXC_TABLE_DEFAULT / 4 + cause];
327 set_handler(EXC_TABLE_DEFAULT / 4 + cause, handler);
328 return previous;
332 static void trap_init_excsave(void)
334 unsigned long excsave1 = (unsigned long)this_cpu_ptr(exc_table);
335 __asm__ __volatile__("wsr %0, excsave1\n" : : "a" (excsave1));
339 * Initialize dispatch tables.
341 * The exception vectors are stored compressed the __init section in the
342 * dispatch_init_table. This function initializes the following three tables
343 * from that compressed table:
344 * - fast user first dispatch table for user exceptions
345 * - fast kernel first dispatch table for kernel exceptions
346 * - default C-handler C-handler called by the default fast handler.
348 * See vectors.S for more details.
351 void __init trap_init(void)
353 int i;
355 /* Setup default vectors. */
357 for(i = 0; i < 64; i++) {
358 set_handler(EXC_TABLE_FAST_USER/4 + i, user_exception);
359 set_handler(EXC_TABLE_FAST_KERNEL/4 + i, kernel_exception);
360 set_handler(EXC_TABLE_DEFAULT/4 + i, do_unhandled);
363 /* Setup specific handlers. */
365 for(i = 0; dispatch_init_table[i].cause >= 0; i++) {
367 int fast = dispatch_init_table[i].fast;
368 int cause = dispatch_init_table[i].cause;
369 void *handler = dispatch_init_table[i].handler;
371 if (fast == 0)
372 set_handler (EXC_TABLE_DEFAULT/4 + cause, handler);
373 if (fast && fast & USER)
374 set_handler (EXC_TABLE_FAST_USER/4 + cause, handler);
375 if (fast && fast & KRNL)
376 set_handler (EXC_TABLE_FAST_KERNEL/4 + cause, handler);
379 /* Initialize EXCSAVE_1 to hold the address of the exception table. */
380 trap_init_excsave();
383 #ifdef CONFIG_SMP
384 void secondary_trap_init(void)
386 trap_init_excsave();
388 #endif
391 * This function dumps the current valid window frame and other base registers.
394 void show_regs(struct pt_regs * regs)
396 int i, wmask;
398 show_regs_print_info(KERN_DEFAULT);
400 wmask = regs->wmask & ~1;
402 for (i = 0; i < 16; i++) {
403 if ((i % 8) == 0)
404 printk(KERN_INFO "a%02d:", i);
405 printk(KERN_CONT " %08lx", regs->areg[i]);
407 printk(KERN_CONT "\n");
409 printk("pc: %08lx, ps: %08lx, depc: %08lx, excvaddr: %08lx\n",
410 regs->pc, regs->ps, regs->depc, regs->excvaddr);
411 printk("lbeg: %08lx, lend: %08lx lcount: %08lx, sar: %08lx\n",
412 regs->lbeg, regs->lend, regs->lcount, regs->sar);
413 if (user_mode(regs))
414 printk("wb: %08lx, ws: %08lx, wmask: %08lx, syscall: %ld\n",
415 regs->windowbase, regs->windowstart, regs->wmask,
416 regs->syscall);
419 static int show_trace_cb(struct stackframe *frame, void *data)
421 if (kernel_text_address(frame->pc)) {
422 printk(" [<%08lx>] ", frame->pc);
423 print_symbol("%s\n", frame->pc);
425 return 0;
428 void show_trace(struct task_struct *task, unsigned long *sp)
430 if (!sp)
431 sp = stack_pointer(task);
433 printk("Call Trace:");
434 #ifdef CONFIG_KALLSYMS
435 printk("\n");
436 #endif
437 walk_stackframe(sp, show_trace_cb, NULL);
438 printk("\n");
442 * This routine abuses get_user()/put_user() to reference pointers
443 * with at least a bit of error checking ...
446 static int kstack_depth_to_print = 24;
448 void show_stack(struct task_struct *task, unsigned long *sp)
450 int i = 0;
451 unsigned long *stack;
453 if (!sp)
454 sp = stack_pointer(task);
455 stack = sp;
457 printk("\nStack: ");
459 for (i = 0; i < kstack_depth_to_print; i++) {
460 if (kstack_end(sp))
461 break;
462 if (i && ((i % 8) == 0))
463 printk("\n ");
464 printk("%08lx ", *sp++);
466 printk("\n");
467 show_trace(task, stack);
470 void show_code(unsigned int *pc)
472 long i;
474 printk("\nCode:");
476 for(i = -3 ; i < 6 ; i++) {
477 unsigned long insn;
478 if (__get_user(insn, pc + i)) {
479 printk(" (Bad address in pc)\n");
480 break;
482 printk("%c%08lx%c",(i?' ':'<'),insn,(i?' ':'>'));
486 DEFINE_SPINLOCK(die_lock);
488 void die(const char * str, struct pt_regs * regs, long err)
490 static int die_counter;
491 int nl = 0;
493 console_verbose();
494 spin_lock_irq(&die_lock);
496 printk("%s: sig: %ld [#%d]\n", str, err, ++die_counter);
497 #ifdef CONFIG_PREEMPT
498 printk("PREEMPT ");
499 nl = 1;
500 #endif
501 if (nl)
502 printk("\n");
503 show_regs(regs);
504 if (!user_mode(regs))
505 show_stack(NULL, (unsigned long*)regs->areg[1]);
507 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
508 spin_unlock_irq(&die_lock);
510 if (in_interrupt())
511 panic("Fatal exception in interrupt");
513 if (panic_on_oops)
514 panic("Fatal exception");
516 do_exit(err);