| 1 | /* |
| 2 | * arch/ubicom32/kernel/traps.c |
| 3 | * Ubicom32 architecture trap handling support. |
| 4 | * |
| 5 | * (C) Copyright 2009, Ubicom, Inc. |
| 6 | * |
| 7 | * This file is part of the Ubicom32 Linux Kernel Port. |
| 8 | * |
| 9 | * The Ubicom32 Linux Kernel Port is free software: you can redistribute |
| 10 | * it and/or modify it under the terms of the GNU General Public License |
| 11 | * as published by the Free Software Foundation, either version 2 of the |
| 12 | * License, or (at your option) any later version. |
| 13 | * |
| 14 | * The Ubicom32 Linux Kernel Port is distributed in the hope that it |
| 15 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied |
| 16 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See |
| 17 | * the GNU General Public License for more details. |
| 18 | * |
| 19 | * You should have received a copy of the GNU General Public License |
| 20 | * along with the Ubicom32 Linux Kernel Port. If not, |
| 21 | * see <http://www.gnu.org/licenses/>. |
| 22 | * |
| 23 | * Ubicom32 implementation derived from (with many thanks): |
| 24 | * arch/m68knommu |
| 25 | * arch/blackfin |
| 26 | * arch/parisc |
| 27 | */ |
| 28 | |
| 29 | /* |
| 30 | * Sets up all exception vectors |
| 31 | */ |
| 32 | #include <linux/sched.h> |
| 33 | #include <linux/signal.h> |
| 34 | #include <linux/kernel.h> |
| 35 | #include <linux/mm.h> |
| 36 | #include <linux/module.h> |
| 37 | #include <linux/types.h> |
| 38 | #include <linux/a.out.h> |
| 39 | #include <linux/user.h> |
| 40 | #include <linux/string.h> |
| 41 | #include <linux/linkage.h> |
| 42 | #include <linux/init.h> |
| 43 | #include <linux/ptrace.h> |
| 44 | #include <linux/kallsyms.h> |
| 45 | #include <linux/compiler.h> |
| 46 | #include <linux/stacktrace.h> |
| 47 | #include <linux/personality.h> |
| 48 | |
| 49 | #include <asm/uaccess.h> |
| 50 | #include <asm/stacktrace.h> |
| 51 | #include <asm/devtree.h> |
| 52 | #include <asm/setup.h> |
| 53 | #include <asm/fpu.h> |
| 54 | #include <asm/system.h> |
| 55 | #include <asm/traps.h> |
| 56 | #include <asm/pgtable.h> |
| 57 | #include <asm/processor.h> |
| 58 | #include <asm/machdep.h> |
| 59 | #include <asm/siginfo.h> |
| 60 | #include <asm/ip5000.h> |
| 61 | #include <asm/thread.h> |
| 62 | |
| 63 | #define TRAP_MAX_STACK_DEPTH 20 |
| 64 | |
| 65 | /* |
| 66 | * These symbols are filled in by the linker. |
| 67 | */ |
| 68 | extern unsigned long _stext; |
| 69 | extern unsigned long _etext; |
| 70 | |
| 71 | extern unsigned long __ocm_text_run_begin; |
| 72 | extern unsigned long __data_begin; |
| 73 | |
| 74 | extern void show_vmas(struct task_struct *task); |
| 75 | |
| 76 | const char *trap_cause_strings[] = { |
| 77 | /*0*/ "inst address decode error", |
| 78 | /*1*/ "inst sync error", |
| 79 | /*2*/ "inst illegal", |
| 80 | /*3*/ "src1 address decode error", |
| 81 | /*4*/ "dst address decode error", |
| 82 | /*5*/ "src1 alignment error", |
| 83 | /*6*/ "dst alignment error", |
| 84 | /*7*/ "src1 sync error", |
| 85 | /*8*/ "dst sync error", |
| 86 | /*9*/ "DCAPT error", |
| 87 | /*10*/ "inst range error", |
| 88 | /*11*/ "src1 range error", |
| 89 | /*12*/ "dst range error", |
| 90 | }; |
| 91 | |
| 92 | /* |
| 93 | * The device tree trap node definition. |
| 94 | */ |
| 95 | struct trapnode { |
| 96 | struct devtree_node dn; |
| 97 | unsigned int intthread; |
| 98 | }; |
| 99 | |
| 100 | static struct trapnode *tn;; |
| 101 | |
| 102 | /* |
| 103 | * trap_interrupt_handler() |
| 104 | * Software Interrupt to ensure that a trap is serviced. |
| 105 | */ |
| 106 | static irqreturn_t trap_interrupt_handler(int irq, void *dummy) |
| 107 | { |
| 108 | /* Do Nothing */ |
| 109 | return IRQ_HANDLED; |
| 110 | } |
| 111 | |
| 112 | /* |
| 113 | * Data used by setup_irq for the timer. |
| 114 | */ |
| 115 | static struct irqaction trap_irq = { |
| 116 | .name = "trap", |
| 117 | .flags = IRQF_DISABLED, |
| 118 | .handler = trap_interrupt_handler, |
| 119 | }; |
| 120 | |
| 121 | /* |
| 122 | * trap_cause_to_str() |
| 123 | * Convert a trap_cause into a series of printk |
| 124 | */ |
| 125 | static void trap_cause_to_str(long status) |
| 126 | { |
| 127 | int bit; |
| 128 | |
| 129 | if ((status & ((1 << TRAP_CAUSE_TOTAL) - 1)) == 0) { |
| 130 | printk(KERN_NOTICE "decode: UNKNOWN CAUSES\n"); |
| 131 | return; |
| 132 | } |
| 133 | |
| 134 | for (bit = 0; bit < TRAP_CAUSE_TOTAL; bit++) { |
| 135 | if (status & (1 << bit)) { |
| 136 | printk(KERN_NOTICE "\tdecode: %08x %s\n", |
| 137 | 1 << bit, trap_cause_strings[bit]); |
| 138 | } |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | /* |
| 143 | * trap_print_information() |
| 144 | * Print the cause of the trap and additional info. |
| 145 | */ |
| 146 | static void trap_print_information(const char *str, struct pt_regs *regs) |
| 147 | { |
| 148 | printk(KERN_WARNING "\n"); |
| 149 | |
| 150 | if (current) { |
| 151 | printk(KERN_WARNING "Process %s (pid: %d)\n", |
| 152 | current->comm, current->pid); |
| 153 | } |
| 154 | |
| 155 | if (current && current->mm) { |
| 156 | printk(KERN_NOTICE "text = 0x%p-0x%p data = 0x%p-0x%p\n" |
| 157 | KERN_NOTICE "bss = 0x%p-0x%p user-stack = 0x%p\n" |
| 158 | KERN_NOTICE "\n", |
| 159 | (void *)current->mm->start_code, |
| 160 | (void *)current->mm->end_code, |
| 161 | (void *)current->mm->start_data, |
| 162 | (void *)current->mm->end_data, |
| 163 | (void *)current->mm->end_data, |
| 164 | (void *)current->mm->brk, |
| 165 | (void *)current->mm->start_stack); |
| 166 | } |
| 167 | |
| 168 | printk(KERN_WARNING "%s: Causes: 0x%08x\n", str, |
| 169 | (unsigned int)regs->trap_cause); |
| 170 | trap_cause_to_str(regs->trap_cause); |
| 171 | show_regs(regs); |
| 172 | show_stack(NULL, (unsigned long *)regs->an[7]); |
| 173 | printk(KERN_NOTICE "--- End Trap --- \n"); |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * dump_stack() |
| 178 | * Dump the stack of the current task. |
| 179 | */ |
| 180 | void dump_stack(void) |
| 181 | { |
| 182 | show_stack(NULL, NULL); |
| 183 | } |
| 184 | EXPORT_SYMBOL(dump_stack); |
| 185 | |
| 186 | /* |
| 187 | * show_stack() |
| 188 | * Print out information from the current stack. |
| 189 | */ |
| 190 | void show_stack(struct task_struct *task, unsigned long *sp) |
| 191 | { |
| 192 | /* |
| 193 | * Allocate just enough entries on the stack. |
| 194 | */ |
| 195 | unsigned int calls[TRAP_MAX_STACK_DEPTH]; |
| 196 | unsigned long code_start; |
| 197 | unsigned long code_end; |
| 198 | unsigned long ocm_code_start = (unsigned long)&__ocm_text_run_begin; |
| 199 | unsigned long ocm_code_end = (unsigned long)&__data_begin; |
| 200 | unsigned long stack_end = (unsigned long)(current->stack + THREAD_SIZE - 8); |
| 201 | unsigned long stack = (unsigned long)sp; |
| 202 | int kernel_stack = 1; |
| 203 | |
| 204 | processor_dram(&code_start, &code_end); |
| 205 | |
| 206 | /* |
| 207 | * Which task are we talking about. |
| 208 | */ |
| 209 | if (!task) { |
| 210 | task = current; |
| 211 | } |
| 212 | |
| 213 | /* |
| 214 | * Find the stack for the task if one was not specified. Otherwise |
| 215 | * use the specified stack. |
| 216 | */ |
| 217 | if (!stack) { |
| 218 | if (task != current) { |
| 219 | stack = task->thread.sp; |
| 220 | stack_end = (unsigned long)task->stack + THREAD_SIZE - 8; |
| 221 | } else { |
| 222 | asm volatile ( |
| 223 | "move.4 %0, SP \n\t" |
| 224 | : "=r" (stack) |
| 225 | ); |
| 226 | } |
| 227 | } |
| 228 | |
| 229 | printk(KERN_NOTICE "Starting backtrace: PID %d '%s'\n", |
| 230 | task->pid, task->comm); |
| 231 | |
| 232 | /* |
| 233 | * We do 2 passes the first pass is Kernel stack is the second |
| 234 | * User stack. |
| 235 | */ |
| 236 | while (kernel_stack) { |
| 237 | unsigned long *handle; |
| 238 | unsigned int i, idx = 0; |
| 239 | struct pt_regs *pt = task_pt_regs(task); |
| 240 | |
| 241 | /* |
| 242 | * If the task is in user mode, reset the start |
| 243 | * and end values for text. |
| 244 | */ |
| 245 | if (__user_mode(stack)) { |
| 246 | if (!(task->personality & FDPIC_FUNCPTRS)) { |
| 247 | printk(KERN_NOTICE " User Stack:\n"); |
| 248 | code_start = task->mm->start_code; |
| 249 | code_end = task->mm->end_code; |
| 250 | } else { |
| 251 | printk(KERN_NOTICE " User Stack (fdpic):\n"); |
| 252 | show_vmas(task); |
| 253 | } |
| 254 | stack_end = task->mm->start_stack; |
| 255 | ocm_code_end = ocm_code_start = 0; |
| 256 | kernel_stack = 0; |
| 257 | } else { |
| 258 | printk(KERN_NOTICE " Kernel Stack:\n"); |
| 259 | } |
| 260 | |
| 261 | /* |
| 262 | * Collect the stack back trace information. |
| 263 | */ |
| 264 | printk(" code[0x%lx-0x%lx]", code_start, code_end); |
| 265 | if (ocm_code_start) { |
| 266 | printk(" ocm_code[0x%lx-0x%lx]", |
| 267 | ocm_code_start, ocm_code_end); |
| 268 | } |
| 269 | printk("\n stack[0x%lx-0x%lx]\n", stack, stack_end); |
| 270 | |
| 271 | handle = (unsigned long*)stack; |
| 272 | while (idx < TRAP_MAX_STACK_DEPTH) { |
| 273 | calls[idx] = stacktrace_iterate(&handle, |
| 274 | code_start, code_end, |
| 275 | ocm_code_start, ocm_code_end, |
| 276 | (unsigned long)stack, stack_end); |
| 277 | if (calls[idx] == 0) { |
| 278 | break; |
| 279 | } |
| 280 | idx++; |
| 281 | } |
| 282 | |
| 283 | /* |
| 284 | * Now print out the data. |
| 285 | */ |
| 286 | printk(KERN_NOTICE " CALL && CALLI on stack:"); |
| 287 | for (i = 0; i < idx; i++) { |
| 288 | printk("%s0x%x, ", (i & 0x3) == 0 ? "\n " : "", |
| 289 | calls[i]); |
| 290 | } |
| 291 | printk(idx == TRAP_MAX_STACK_DEPTH ? "...\n" : "\n"); |
| 292 | |
| 293 | /* |
| 294 | * If we are doing user stack we are done |
| 295 | */ |
| 296 | if (!kernel_stack) { |
| 297 | break; |
| 298 | } |
| 299 | |
| 300 | /* |
| 301 | * Does this kernel stack have a mm (i.e. is it user) |
| 302 | */ |
| 303 | if (!task->mm) { |
| 304 | printk("No mm for userspace stack.\n"); |
| 305 | break; |
| 306 | } |
| 307 | /* |
| 308 | * Get the user-mode stack (if any) |
| 309 | */ |
| 310 | stack = pt->an[7]; |
| 311 | printk(KERN_NOTICE "Userspace stack at 0x%lx frame type %d\n", |
| 312 | stack, (int)pt->frame_type); |
| 313 | if (!__user_mode(stack)) { |
| 314 | break; |
| 315 | } |
| 316 | } |
| 317 | } |
| 318 | |
| 319 | /* |
| 320 | * die_if_kernel() |
| 321 | * Determine if we are in kernel mode and if so print stuff out and die. |
| 322 | */ |
| 323 | void die_if_kernel(char *str, struct pt_regs *regs, long trap_cause) |
| 324 | { |
| 325 | unsigned int s3value; |
| 326 | |
| 327 | if (user_mode(regs)) { |
| 328 | return; |
| 329 | } |
| 330 | |
| 331 | console_verbose(); |
| 332 | trap_print_information(str, regs); |
| 333 | |
| 334 | /* |
| 335 | * If the debugger is attached via the hardware mailbox protocol, |
| 336 | * go into an infinite loop and the debugger will figure things out. |
| 337 | */ |
| 338 | asm volatile ( |
| 339 | "move.4 %0, scratchpad3" |
| 340 | : "=r" (s3value) |
| 341 | ); |
| 342 | if (s3value) { |
| 343 | asm volatile("1: jmpt.t 1b"); |
| 344 | } |
| 345 | |
| 346 | /* |
| 347 | * Set the debug taint value. |
| 348 | */ |
| 349 | add_taint(TAINT_DIE); |
| 350 | do_exit(SIGSEGV); |
| 351 | } |
| 352 | |
| 353 | /* |
| 354 | * trap_handler() |
| 355 | * Handle traps. |
| 356 | * |
| 357 | * Traps are treated as interrupts and registered with the LDSR. When |
| 358 | * the LDSR takes the interrupt, it will determine if a trap has occurred |
| 359 | * and service the trap prior to servicing the interrupt. |
| 360 | * |
| 361 | * This function is directly called by the LDSR. |
| 362 | */ |
| 363 | void trap_handler(int irq, struct pt_regs *regs) |
| 364 | { |
| 365 | int sig = SIGSEGV; |
| 366 | siginfo_t info; |
| 367 | unsigned int trap_cause = regs->trap_cause; |
| 368 | |
| 369 | BUG_ON(!irqs_disabled()); |
| 370 | |
| 371 | /* |
| 372 | * test if in kernel and die. |
| 373 | */ |
| 374 | die_if_kernel("Kernel Trap", regs, trap_cause); |
| 375 | |
| 376 | /* |
| 377 | * User process problem, setup a signal for this process |
| 378 | */ |
| 379 | if ((trap_cause & (1 << TRAP_CAUSE_DST_RANGE_ERR)) || |
| 380 | (trap_cause & (1 << TRAP_CAUSE_SRC1_RANGE_ERR)) || |
| 381 | (trap_cause & (1 << TRAP_CAUSE_I_RANGE_ERR))) { |
| 382 | sig = SIGSEGV; |
| 383 | info.si_code = SEGV_MAPERR; |
| 384 | } else if ((trap_cause & (1 << TRAP_CAUSE_DST_MISALIGNED)) || |
| 385 | (trap_cause & (1 << TRAP_CAUSE_SRC1_MISALIGNED))) { |
| 386 | sig = SIGBUS; |
| 387 | info.si_code = BUS_ADRALN; |
| 388 | } else if ((trap_cause & (1 << TRAP_CAUSE_DST_DECODE_ERR)) || |
| 389 | (trap_cause & (1 << TRAP_CAUSE_SRC1_DECODE_ERR))) { |
| 390 | sig = SIGILL; |
| 391 | info.si_code = ILL_ILLOPN; |
| 392 | } else if ((trap_cause & (1 << TRAP_CAUSE_ILLEGAL_INST))) { |
| 393 | /* |
| 394 | * Check for software break point and if found signal trap |
| 395 | * not illegal instruction. |
| 396 | */ |
| 397 | unsigned long instruction; |
| 398 | if (between(regs->pc, KERNELSTART, memory_end) && |
| 399 | (regs->pc & 3) == 0 && |
| 400 | get_user(instruction, (unsigned long *)regs->pc) == 0) { |
| 401 | |
| 402 | /* |
| 403 | * This used to be 0xaabbccdd but it turns out |
| 404 | * that is now valid in ubicom32v4 isa so we |
| 405 | * have switched to 0xfabbccdd |
| 406 | */ |
| 407 | if ((instruction == 0xfabbccdd) || |
| 408 | (instruction == 0xaabbccdd)) { |
| 409 | sig = SIGTRAP; |
| 410 | info.si_code = TRAP_BRKPT; |
| 411 | goto send_signal; |
| 412 | } |
| 413 | } |
| 414 | sig = SIGILL; |
| 415 | info.si_code = ILL_ILLOPC; |
| 416 | } else if ((trap_cause & (1 << TRAP_CAUSE_I_DECODE_ERR))) { |
| 417 | sig = SIGILL; |
| 418 | info.si_code = ILL_ILLOPC; |
| 419 | } else if ((trap_cause & (1 << TRAP_CAUSE_DCAPT))) { |
| 420 | sig = SIGTRAP; |
| 421 | info.si_code = TRAP_TRACE; |
| 422 | } |
| 423 | |
| 424 | /* |
| 425 | * Print a trap information block to the console, do not |
| 426 | * print this above the case because we don't want it |
| 427 | * printed for software break points. |
| 428 | */ |
| 429 | trap_print_information("User Trap", regs); |
| 430 | |
| 431 | send_signal: |
| 432 | |
| 433 | force_sig_info(sig, &info, current); |
| 434 | |
| 435 | /* |
| 436 | * Interrupts are disabled, re-enable them now. |
| 437 | */ |
| 438 | if (!irqs_disabled()) { |
| 439 | printk(KERN_EMERG "interrupts enabled on exit, irq=%d, regs=%p", |
| 440 | irq, regs); |
| 441 | BUG(); |
| 442 | } |
| 443 | } |
| 444 | |
| 445 | /* |
| 446 | * trap_init_interrupt() |
| 447 | * We need a 2nd trap handling init that will occur after init_IRQ(). |
| 448 | */ |
| 449 | void __init trap_init_interrupt(void) |
| 450 | { |
| 451 | int err; |
| 452 | unsigned char tirq; |
| 453 | struct devtree_node *dn = (struct devtree_node *)tn; |
| 454 | |
| 455 | /* |
| 456 | * Now setup the Software IRQ so that if a trap occurs the LDSR |
| 457 | * is started. The irq is there just to "force" the LDSR to run. |
| 458 | */ |
| 459 | if (!tn) { |
| 460 | printk(KERN_WARNING "trap_init_interrupt skipped.\n"); |
| 461 | return; |
| 462 | } |
| 463 | |
| 464 | err = devtree_irq(dn, NULL, &tirq); |
| 465 | if (err) { |
| 466 | printk(KERN_WARNING "error obtaining trap irq value: %d\n", |
| 467 | err); |
| 468 | return; |
| 469 | } |
| 470 | |
| 471 | if (tirq == DEVTREE_IRQ_NONE) { |
| 472 | printk(KERN_WARNING "trap irq not available: %d\n", tirq); |
| 473 | return; |
| 474 | } |
| 475 | |
| 476 | err = setup_irq(tirq, &trap_irq); |
| 477 | if (err) { |
| 478 | printk(KERN_WARNING "trap irq setup failed: %d\n", err); |
| 479 | return; |
| 480 | } |
| 481 | |
| 482 | /* |
| 483 | * Let ultra know which thread is handling the traps and |
| 484 | * what the interrupt to use is. |
| 485 | */ |
| 486 | tn->intthread = ldsr_get_threadid(); |
| 487 | |
| 488 | /* |
| 489 | * Tell the LDSR about our IRQ so that it will unsuspend |
| 490 | * if one occurs while waiting for the per thread lock. |
| 491 | */ |
| 492 | ldsr_set_trap_irq(tirq); |
| 493 | } |
| 494 | |
| 495 | /* |
| 496 | * trap_init() |
| 497 | * init trap handling |
| 498 | * |
| 499 | * Trap handling is done through the ldsr. Every time an interrupt |
| 500 | * occurs, the LDSR looks for threads that are listed in the TRAP |
| 501 | * register and forces a call to the trap handler. |
| 502 | */ |
| 503 | void __init trap_init(void) |
| 504 | { |
| 505 | /* |
| 506 | * If we do not have a trap node in the device tree, we leave the fault |
| 507 | * handling to the underlying hardware. |
| 508 | */ |
| 509 | tn = (struct trapnode *)devtree_find_node("traps"); |
| 510 | if (!tn) { |
| 511 | printk(KERN_WARNING "traps are not handled by linux\n"); |
| 512 | return; |
| 513 | } |
| 514 | } |
| 515 | |
