arch/xtensa/kernel/traps.c

   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>
  32 #include <linux/delay.h>
  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 { 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 static dispatch_init_table_t __initdata dispatch_init_table[] = {
  87
  88 { EXCCAUSE_ILLEGAL_INSTRUCTION, 0,         do_illegal_instruction},
  89 { EXCCAUSE_SYSTEM_CALL,         KRNL,      fast_syscall_kernel },
  90 { EXCCAUSE_SYSTEM_CALL,         USER,      fast_syscall_user },
  91 { EXCCAUSE_SYSTEM_CALL,         0,         system_call },
  92 /* EXCCAUSE_INSTRUCTION_FETCH unhandled */
  93 /* EXCCAUSE_LOAD_STORE_ERROR unhandled*/
  94 { EXCCAUSE_LEVEL1_INTERRUPT,    0,         do_interrupt },
  95 { EXCCAUSE_ALLOCA,              USER|KRNL, fast_alloca },
  96 /* EXCCAUSE_INTEGER_DIVIDE_BY_ZERO unhandled */
  97 /* EXCCAUSE_PRIVILEGED unhandled */
  98 #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION
  99 #ifdef CONFIG_UNALIGNED_USER
 100 { EXCCAUSE_UNALIGNED,           USER,      fast_unaligned },
 101 #else
 102 { EXCCAUSE_UNALIGNED,           0,         do_unaligned_user },
 103 #endif
 104 { EXCCAUSE_UNALIGNED,           KRNL,      fast_unaligned },
 105 #endif
 106 { EXCCAUSE_ITLB_MISS,           0,         do_page_fault },
 107 { EXCCAUSE_ITLB_MISS,           USER|KRNL, fast_second_level_miss},
 108 { EXCCAUSE_ITLB_MULTIHIT,               0,         do_multihit },
 109 { EXCCAUSE_ITLB_PRIVILEGE,      0,         do_page_fault },
 110 /* EXCCAUSE_SIZE_RESTRICTION unhandled */
 111 { EXCCAUSE_FETCH_CACHE_ATTRIBUTE,       0,         do_page_fault },
 112 { EXCCAUSE_DTLB_MISS,           USER|KRNL, fast_second_level_miss},
 113 { EXCCAUSE_DTLB_MISS,           0,         do_page_fault },
 114 { EXCCAUSE_DTLB_MULTIHIT,               0,         do_multihit },
 115 { EXCCAUSE_DTLB_PRIVILEGE,      0,         do_page_fault },
 116 /* EXCCAUSE_DTLB_SIZE_RESTRICTION unhandled */
 117 { EXCCAUSE_STORE_CACHE_ATTRIBUTE,       USER|KRNL, fast_store_prohibited },
 118 { EXCCAUSE_STORE_CACHE_ATTRIBUTE,       0,         do_page_fault },
 119 { EXCCAUSE_LOAD_CACHE_ATTRIBUTE,        0,         do_page_fault },
 120 /* XCCHAL_EXCCAUSE_FLOATING_POINT unhandled */
 121 <<<<<<< HEAD:arch/xtensa/kernel/traps.c
 122 #if (XCHAL_CP_MASK & 1)
 123 =======
 124 #if XTENSA_HAVE_COPROCESSOR(0)
 125 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/xtensa/kernel/traps.c
 126 COPROCESSOR(0),
 127 #endif
 128 <<<<<<< HEAD:arch/xtensa/kernel/traps.c
 129 #if (XCHAL_CP_MASK & 2)
 130 =======
 131 #if XTENSA_HAVE_COPROCESSOR(1)
 132 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/xtensa/kernel/traps.c
 133 COPROCESSOR(1),
 134 #endif
 135 <<<<<<< HEAD:arch/xtensa/kernel/traps.c
 136 #if (XCHAL_CP_MASK & 4)
 137 =======
 138 #if XTENSA_HAVE_COPROCESSOR(2)
 139 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/xtensa/kernel/traps.c
 140 COPROCESSOR(2),
 141 #endif
 142 <<<<<<< HEAD:arch/xtensa/kernel/traps.c
 143 #if (XCHAL_CP_MASK & 8)
 144 =======
 145 #if XTENSA_HAVE_COPROCESSOR(3)
 146 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/xtensa/kernel/traps.c
 147 COPROCESSOR(3),
 148 #endif
 149 <<<<<<< HEAD:arch/xtensa/kernel/traps.c
 150 #if (XCHAL_CP_MASK & 16)
 151 =======
 152 #if XTENSA_HAVE_COPROCESSOR(4)
 153 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/xtensa/kernel/traps.c
 154 COPROCESSOR(4),
 155 #endif
 156 <<<<<<< HEAD:arch/xtensa/kernel/traps.c
 157 #if (XCHAL_CP_MASK & 32)
 158 =======
 159 #if XTENSA_HAVE_COPROCESSOR(5)
 160 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/xtensa/kernel/traps.c
 161 COPROCESSOR(5),
 162 #endif
 163 <<<<<<< HEAD:arch/xtensa/kernel/traps.c
 164 #if (XCHAL_CP_MASK & 64)
 165 =======
 166 #if XTENSA_HAVE_COPROCESSOR(6)
 167 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/xtensa/kernel/traps.c
 168 COPROCESSOR(6),
 169 #endif
 170 <<<<<<< HEAD:arch/xtensa/kernel/traps.c
 171 #if (XCHAL_CP_MASK & 128)
 172 =======
 173 #if XTENSA_HAVE_COPROCESSOR(7)
 174 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/xtensa/kernel/traps.c
 175 COPROCESSOR(7),
 176 #endif
 177 { EXCCAUSE_MAPPED_DEBUG,                0,              do_debug },
 178 { -1, -1, 0 }
 179
 180 };
 181
 182 /* The exception table <exc_table> serves two functions:
 183  * 1. it contains three dispatch tables (fast_user, fast_kernel, default-c)
 184  * 2. it is a temporary memory buffer for the exception handlers.
 185  */
 186
 187 unsigned long exc_table[EXC_TABLE_SIZE/4];
 188
 189 void die(const char*, struct pt_regs*, long);
 190
 191 static inline void
 192 __die_if_kernel(const char *str, struct pt_regs *regs, long err)
 193 {
 194         if (!user_mode(regs))
 195                 die(str, regs, err);
 196 }
 197
 198 /*
 199  * Unhandled Exceptions. Kill user task or panic if in kernel space.
 200  */
 201
 202 void do_unhandled(struct pt_regs *regs, unsigned long exccause)
 203 {
 204         __die_if_kernel("Caught unhandled exception - should not happen",
 205                         regs, SIGKILL);
 206
 207         /* If in user mode, send SIGILL signal to current process */
 208         printk("Caught unhandled exception in '%s' "
 209                "(pid = %d, pc = %#010lx) - should not happen\n"
 210                "\tEXCCAUSE is %ld\n",
 211                current->comm, task_pid_nr(current), regs->pc, exccause);
 212         force_sig(SIGILL, current);
 213 }
 214
 215 /*
 216  * Multi-hit exception. This if fatal!
 217  */
 218
 219 void do_multihit(struct pt_regs *regs, unsigned long exccause)
 220 {
 221         die("Caught multihit exception", regs, SIGKILL);
 222 }
 223
 224 /*
 225  * Level-1 interrupt.
 226  * We currently have no priority encoding.
 227  */
 228
 229 unsigned long ignored_level1_interrupts;
 230 extern void do_IRQ(int, struct pt_regs *);
 231
 232 void do_interrupt (struct pt_regs *regs)
 233 {
 234         unsigned long intread = get_sr (INTREAD);
 235         unsigned long intenable = get_sr (INTENABLE);
 236         int i, mask;
 237
 238         /* Handle all interrupts (no priorities).
 239          * (Clear the interrupt before processing, in case it's
 240          *  edge-triggered or software-generated)
 241          */
 242
 243         for (i=0, mask = 1; i < XCHAL_NUM_INTERRUPTS; i++, mask <<= 1) {
 244                 if (mask & (intread & intenable)) {
 245                         set_sr (mask, INTCLEAR);
 246                         do_IRQ (i,regs);
 247                 }
 248         }
 249 }
 250
 251 /*
 252  * Illegal instruction. Fatal if in kernel space.
 253  */
 254
 255 void
 256 do_illegal_instruction(struct pt_regs *regs)
 257 {
 258         __die_if_kernel("Illegal instruction in kernel", regs, SIGKILL);
 259
 260         /* If in user mode, send SIGILL signal to current process. */
 261
 262         printk("Illegal Instruction in '%s' (pid = %d, pc = %#010lx)\n",
 263             current->comm, task_pid_nr(current), regs->pc);
 264         force_sig(SIGILL, current);
 265 }
 266
 267
 268 /*
 269  * Handle unaligned memory accesses from user space. Kill task.
 270  *
 271  * If CONFIG_UNALIGNED_USER is not set, we don't allow unaligned memory
 272  * accesses causes from user space.
 273  */
 274
 275 #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION
 276 #ifndef CONFIG_UNALIGNED_USER
 277 void
 278 do_unaligned_user (struct pt_regs *regs)
 279 {
 280         siginfo_t info;
 281
 282         __die_if_kernel("Unhandled unaligned exception in kernel",
 283                         regs, SIGKILL);
 284
 285         current->thread.bad_vaddr = regs->excvaddr;
 286         current->thread.error_code = -3;
 287         printk("Unaligned memory access to %08lx in '%s' "
 288                "(pid = %d, pc = %#010lx)\n",
 289                regs->excvaddr, current->comm, task_pid_nr(current), regs->pc);
 290         info.si_signo = SIGBUS;
 291         info.si_errno = 0;
 292         info.si_code = BUS_ADRALN;
 293         info.si_addr = (void *) regs->excvaddr;
 294         force_sig_info(SIGSEGV, &info, current);
 295
 296 }
 297 #endif
 298 #endif
 299
 300 void
 301 do_debug(struct pt_regs *regs)
 302 {
 303 #ifdef CONFIG_KGDB
 304         /* If remote debugging is configured AND enabled, we give control to
 305          * kgdb.  Otherwise, we fall through, perhaps giving control to the
 306          * native debugger.
 307          */
 308
 309         if (gdb_enter) {
 310                 extern void gdb_handle_exception(struct pt_regs *);
 311                 gdb_handle_exception(regs);
 312                 return_from_debug_flag = 1;
 313                 return;
 314         }
 315 #endif
 316
 317         __die_if_kernel("Breakpoint in kernel", regs, SIGKILL);
 318
 319         /* If in user mode, send SIGTRAP signal to current process */
 320
 321         force_sig(SIGTRAP, current);
 322 }
 323
 324
 325 /*
 326  * Initialize dispatch tables.
 327  *
 328  * The exception vectors are stored compressed the __init section in the
 329  * dispatch_init_table. This function initializes the following three tables
 330  * from that compressed table:
 331  * - fast user          first dispatch table for user exceptions
 332  * - fast kernel        first dispatch table for kernel exceptions
 333  * - default C-handler  C-handler called by the default fast handler.
 334  *
 335  * See vectors.S for more details.
 336  */
 337
 338 #define set_handler(idx,handler) (exc_table[idx] = (unsigned long) (handler))
 339
 340 void __init trap_init(void)
 341 {
 342         int i;
 343
 344         /* Setup default vectors. */
 345
 346         for(i = 0; i < 64; i++) {
 347                 set_handler(EXC_TABLE_FAST_USER/4   + i, user_exception);
 348                 set_handler(EXC_TABLE_FAST_KERNEL/4 + i, kernel_exception);
 349                 set_handler(EXC_TABLE_DEFAULT/4 + i, do_unhandled);
 350         }
 351
 352         /* Setup specific handlers. */
 353
 354         for(i = 0; dispatch_init_table[i].cause >= 0; i++) {
 355
 356                 int fast = dispatch_init_table[i].fast;
 357                 int cause = dispatch_init_table[i].cause;
 358                 void *handler = dispatch_init_table[i].handler;
 359
 360                 if (fast == 0)
 361                         set_handler (EXC_TABLE_DEFAULT/4 + cause, handler);
 362                 if (fast && fast & USER)
 363                         set_handler (EXC_TABLE_FAST_USER/4 + cause, handler);
 364                 if (fast && fast & KRNL)
 365                         set_handler (EXC_TABLE_FAST_KERNEL/4 + cause, handler);
 366         }
 367
 368         /* Initialize EXCSAVE_1 to hold the address of the exception table. */
 369
 370         i = (unsigned long)exc_table;
 371         __asm__ __volatile__("wsr  %0, "__stringify(EXCSAVE_1)"\n" : : "a" (i));
 372 }
 373
 374 /*
 375  * This function dumps the current valid window frame and other base registers.
 376  */
 377
 378 void show_regs(struct pt_regs * regs)
 379 {
 380         int i, wmask;
 381
 382         wmask = regs->wmask & ~1;
 383
 384 <<<<<<< HEAD:arch/xtensa/kernel/traps.c
 385         for (i = 0; i < 32; i++) {
 386                 if (wmask & (1 << (i / 4)))
 387                         break;
 388 =======
 389         for (i = 0; i < 16; i++) {
 390 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/xtensa/kernel/traps.c
 391                 if ((i % 8) == 0)
 392                         printk ("\n" KERN_INFO "a%02d: ", i);
 393                 printk("%08lx ", regs->areg[i]);
 394         }
 395         printk("\n");
 396
 397         printk("pc: %08lx, ps: %08lx, depc: %08lx, excvaddr: %08lx\n",
 398                regs->pc, regs->ps, regs->depc, regs->excvaddr);
 399         printk("lbeg: %08lx, lend: %08lx lcount: %08lx, sar: %08lx\n",
 400                regs->lbeg, regs->lend, regs->lcount, regs->sar);
 401         if (user_mode(regs))
 402                 printk("wb: %08lx, ws: %08lx, wmask: %08lx, syscall: %ld\n",
 403                        regs->windowbase, regs->windowstart, regs->wmask,
 404                        regs->syscall);
 405 }
 406
 407 void show_trace(struct task_struct *task, unsigned long *sp)
 408 {
 409         unsigned long a0, a1, pc;
 410         unsigned long sp_start, sp_end;
 411
 412         a1 = (unsigned long)sp;
 413
 414         if (a1 == 0)
 415                 __asm__ __volatile__ ("mov %0, a1\n" : "=a"(a1));
 416
 417
 418         sp_start = a1 & ~(THREAD_SIZE-1);
 419         sp_end = sp_start + THREAD_SIZE;
 420
 421         printk("Call Trace:");
 422 #ifdef CONFIG_KALLSYMS
 423         printk("\n");
 424 #endif
 425         spill_registers();
 426
 427         while (a1 > sp_start && a1 < sp_end) {
 428                 sp = (unsigned long*)a1;
 429
 430                 a0 = *(sp - 4);
 431                 a1 = *(sp - 3);
 432
 433                 if (a1 <= (unsigned long) sp)
 434                         break;
 435
 436                 pc = MAKE_PC_FROM_RA(a0, a1);
 437
 438                 if (kernel_text_address(pc)) {
 439                         printk(" [<%08lx>] ", pc);
 440                         print_symbol("%s\n", pc);
 441                 }
 442         }
 443         printk("\n");
 444 }
 445
 446 /*
 447  * This routine abuses get_user()/put_user() to reference pointers
 448  * with at least a bit of error checking ...
 449  */
 450
 451 static int kstack_depth_to_print = 24;
 452
 453 void show_stack(struct task_struct *task, unsigned long *sp)
 454 {
 455         int i = 0;
 456         unsigned long *stack;
 457
 458         if (sp == 0)
 459                 __asm__ __volatile__ ("mov %0, a1\n" : "=a"(sp));
 460
 461         stack = sp;
 462
 463         printk("\nStack: ");
 464
 465         for (i = 0; i < kstack_depth_to_print; i++) {
 466                 if (kstack_end(sp))
 467                         break;
 468                 if (i && ((i % 8) == 0))
 469                         printk("\n       ");
 470                 printk("%08lx ", *sp++);
 471         }
 472         printk("\n");
 473         show_trace(task, stack);
 474 }
 475
 476 void dump_stack(void)
 477 {
 478         show_stack(current, NULL);
 479 }
 480
 481 EXPORT_SYMBOL(dump_stack);
 482
 483
 484 void show_code(unsigned int *pc)
 485 {
 486         long i;
 487
 488         printk("\nCode:");
 489
 490         for(i = -3 ; i < 6 ; i++) {
 491                 unsigned long insn;
 492                 if (__get_user(insn, pc + i)) {
 493                         printk(" (Bad address in pc)\n");
 494                         break;
 495                 }
 496                 printk("%c%08lx%c",(i?' ':'<'),insn,(i?' ':'>'));
 497         }
 498 }
 499
 500 DEFINE_SPINLOCK(die_lock);
 501
 502 void die(const char * str, struct pt_regs * regs, long err)
 503 {
 504         static int die_counter;
 505         int nl = 0;
 506
 507         console_verbose();
 508         spin_lock_irq(&die_lock);
 509
 510         printk("%s: sig: %ld [#%d]\n", str, err, ++die_counter);
 511 #ifdef CONFIG_PREEMPT
 512         printk("PREEMPT ");
 513         nl = 1;
 514 #endif
 515         if (nl)
 516                 printk("\n");
 517         show_regs(regs);
 518         if (!user_mode(regs))
 519                 show_stack(NULL, (unsigned long*)regs->areg[1]);
 520
 521         add_taint(TAINT_DIE);
 522         spin_unlock_irq(&die_lock);
 523
 524         if (in_interrupt())
 525                 panic("Fatal exception in interrupt");
 526
 527         if (panic_on_oops)
 528                 panic("Fatal exception");
 529
 530         do_exit(err);
 531 }
 532
 533