linux/arch/openrisc/kernel/traps.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * OpenRISC traps.c
   4 *
   5 * Linux architectural port borrowing liberally from similar works of
   6 * others.  All original copyrights apply as per the original source
   7 * declaration.
   8 *
   9 * Modifications for the OpenRISC architecture:
  10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  12 *
  13 *  Here we handle the break vectors not used by the system call
  14 *  mechanism, as well as some general stack/register dumping
  15 *  things.
  16 */
  17
  18#include <linux/init.h>
  19#include <linux/sched.h>
  20#include <linux/sched/debug.h>
  21#include <linux/sched/task_stack.h>
  22#include <linux/kernel.h>
  23#include <linux/extable.h>
  24#include <linux/kmod.h>
  25#include <linux/string.h>
  26#include <linux/errno.h>
  27#include <linux/ptrace.h>
  28#include <linux/timer.h>
  29#include <linux/mm.h>
  30#include <linux/kallsyms.h>
  31#include <linux/uaccess.h>
  32
  33#include <asm/io.h>
  34#include <asm/pgtable.h>
  35#include <asm/unwinder.h>
  36#include <asm/sections.h>
  37
  38int kstack_depth_to_print = 0x180;
  39int lwa_flag;
  40unsigned long __user *lwa_addr;
  41
  42void print_trace(void *data, unsigned long addr, int reliable)
  43{
  44        pr_emerg("[<%p>] %s%pS\n", (void *) addr, reliable ? "" : "? ",
  45               (void *) addr);
  46}
  47
  48/* displays a short stack trace */
  49void show_stack(struct task_struct *task, unsigned long *esp)
  50{
  51        if (esp == NULL)
  52                esp = (unsigned long *)&esp;
  53
  54        pr_emerg("Call trace:\n");
  55        unwind_stack(NULL, esp, print_trace);
  56}
  57
  58void show_trace_task(struct task_struct *tsk)
  59{
  60        /*
  61         * TODO: SysRq-T trace dump...
  62         */
  63}
  64
  65void show_registers(struct pt_regs *regs)
  66{
  67        int i;
  68        int in_kernel = 1;
  69        unsigned long esp;
  70
  71        esp = (unsigned long)(regs->sp);
  72        if (user_mode(regs))
  73                in_kernel = 0;
  74
  75        printk("CPU #: %d\n"
  76               "   PC: %08lx    SR: %08lx    SP: %08lx\n",
  77               smp_processor_id(), regs->pc, regs->sr, regs->sp);
  78        printk("GPR00: %08lx GPR01: %08lx GPR02: %08lx GPR03: %08lx\n",
  79               0L, regs->gpr[1], regs->gpr[2], regs->gpr[3]);
  80        printk("GPR04: %08lx GPR05: %08lx GPR06: %08lx GPR07: %08lx\n",
  81               regs->gpr[4], regs->gpr[5], regs->gpr[6], regs->gpr[7]);
  82        printk("GPR08: %08lx GPR09: %08lx GPR10: %08lx GPR11: %08lx\n",
  83               regs->gpr[8], regs->gpr[9], regs->gpr[10], regs->gpr[11]);
  84        printk("GPR12: %08lx GPR13: %08lx GPR14: %08lx GPR15: %08lx\n",
  85               regs->gpr[12], regs->gpr[13], regs->gpr[14], regs->gpr[15]);
  86        printk("GPR16: %08lx GPR17: %08lx GPR18: %08lx GPR19: %08lx\n",
  87               regs->gpr[16], regs->gpr[17], regs->gpr[18], regs->gpr[19]);
  88        printk("GPR20: %08lx GPR21: %08lx GPR22: %08lx GPR23: %08lx\n",
  89               regs->gpr[20], regs->gpr[21], regs->gpr[22], regs->gpr[23]);
  90        printk("GPR24: %08lx GPR25: %08lx GPR26: %08lx GPR27: %08lx\n",
  91               regs->gpr[24], regs->gpr[25], regs->gpr[26], regs->gpr[27]);
  92        printk("GPR28: %08lx GPR29: %08lx GPR30: %08lx GPR31: %08lx\n",
  93               regs->gpr[28], regs->gpr[29], regs->gpr[30], regs->gpr[31]);
  94        printk("  RES: %08lx oGPR11: %08lx\n",
  95               regs->gpr[11], regs->orig_gpr11);
  96
  97        printk("Process %s (pid: %d, stackpage=%08lx)\n",
  98               current->comm, current->pid, (unsigned long)current);
  99        /*
 100         * When in-kernel, we also print out the stack and code at the
 101         * time of the fault..
 102         */
 103        if (in_kernel) {
 104
 105                printk("\nStack: ");
 106                show_stack(NULL, (unsigned long *)esp);
 107
 108                printk("\nCode: ");
 109                if (regs->pc < PAGE_OFFSET)
 110                        goto bad;
 111
 112                for (i = -24; i < 24; i++) {
 113                        unsigned char c;
 114                        if (__get_user(c, &((unsigned char *)regs->pc)[i])) {
 115bad:
 116                                printk(" Bad PC value.");
 117                                break;
 118                        }
 119
 120                        if (i == 0)
 121                                printk("(%02x) ", c);
 122                        else
 123                                printk("%02x ", c);
 124                }
 125        }
 126        printk("\n");
 127}
 128
 129void nommu_dump_state(struct pt_regs *regs,
 130                      unsigned long ea, unsigned long vector)
 131{
 132        int i;
 133        unsigned long addr, stack = regs->sp;
 134
 135        printk("\n\r[nommu_dump_state] :: ea %lx, vector %lx\n\r", ea, vector);
 136
 137        printk("CPU #: %d\n"
 138               "   PC: %08lx    SR: %08lx    SP: %08lx\n",
 139               0, regs->pc, regs->sr, regs->sp);
 140        printk("GPR00: %08lx GPR01: %08lx GPR02: %08lx GPR03: %08lx\n",
 141               0L, regs->gpr[1], regs->gpr[2], regs->gpr[3]);
 142        printk("GPR04: %08lx GPR05: %08lx GPR06: %08lx GPR07: %08lx\n",
 143               regs->gpr[4], regs->gpr[5], regs->gpr[6], regs->gpr[7]);
 144        printk("GPR08: %08lx GPR09: %08lx GPR10: %08lx GPR11: %08lx\n",
 145               regs->gpr[8], regs->gpr[9], regs->gpr[10], regs->gpr[11]);
 146        printk("GPR12: %08lx GPR13: %08lx GPR14: %08lx GPR15: %08lx\n",
 147               regs->gpr[12], regs->gpr[13], regs->gpr[14], regs->gpr[15]);
 148        printk("GPR16: %08lx GPR17: %08lx GPR18: %08lx GPR19: %08lx\n",
 149               regs->gpr[16], regs->gpr[17], regs->gpr[18], regs->gpr[19]);
 150        printk("GPR20: %08lx GPR21: %08lx GPR22: %08lx GPR23: %08lx\n",
 151               regs->gpr[20], regs->gpr[21], regs->gpr[22], regs->gpr[23]);
 152        printk("GPR24: %08lx GPR25: %08lx GPR26: %08lx GPR27: %08lx\n",
 153               regs->gpr[24], regs->gpr[25], regs->gpr[26], regs->gpr[27]);
 154        printk("GPR28: %08lx GPR29: %08lx GPR30: %08lx GPR31: %08lx\n",
 155               regs->gpr[28], regs->gpr[29], regs->gpr[30], regs->gpr[31]);
 156        printk("  RES: %08lx oGPR11: %08lx\n",
 157               regs->gpr[11], regs->orig_gpr11);
 158
 159        printk("Process %s (pid: %d, stackpage=%08lx)\n",
 160               ((struct task_struct *)(__pa(current)))->comm,
 161               ((struct task_struct *)(__pa(current)))->pid,
 162               (unsigned long)current);
 163
 164        printk("\nStack: ");
 165        printk("Stack dump [0x%08lx]:\n", (unsigned long)stack);
 166        for (i = 0; i < kstack_depth_to_print; i++) {
 167                if (((long)stack & (THREAD_SIZE - 1)) == 0)
 168                        break;
 169                stack++;
 170
 171                printk("%lx :: sp + %02d: 0x%08lx\n", stack, i * 4,
 172                       *((unsigned long *)(__pa(stack))));
 173        }
 174        printk("\n");
 175
 176        printk("Call Trace:   ");
 177        i = 1;
 178        while (((long)stack & (THREAD_SIZE - 1)) != 0) {
 179                addr = *((unsigned long *)__pa(stack));
 180                stack++;
 181
 182                if (kernel_text_address(addr)) {
 183                        if (i && ((i % 6) == 0))
 184                                printk("\n ");
 185                        printk(" [<%08lx>]", addr);
 186                        i++;
 187                }
 188        }
 189        printk("\n");
 190
 191        printk("\nCode: ");
 192
 193        for (i = -24; i < 24; i++) {
 194                unsigned char c;
 195                c = ((unsigned char *)(__pa(regs->pc)))[i];
 196
 197                if (i == 0)
 198                        printk("(%02x) ", c);
 199                else
 200                        printk("%02x ", c);
 201        }
 202        printk("\n");
 203}
 204
 205/* This is normally the 'Oops' routine */
 206void die(const char *str, struct pt_regs *regs, long err)
 207{
 208
 209        console_verbose();
 210        printk("\n%s#: %04lx\n", str, err & 0xffff);
 211        show_registers(regs);
 212#ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
 213        printk("\n\nUNHANDLED_EXCEPTION: entering infinite loop\n");
 214
 215        /* shut down interrupts */
 216        local_irq_disable();
 217
 218        __asm__ __volatile__("l.nop   1");
 219        do {} while (1);
 220#endif
 221        do_exit(SIGSEGV);
 222}
 223
 224/* This is normally the 'Oops' routine */
 225void die_if_kernel(const char *str, struct pt_regs *regs, long err)
 226{
 227        if (user_mode(regs))
 228                return;
 229
 230        die(str, regs, err);
 231}
 232
 233void unhandled_exception(struct pt_regs *regs, int ea, int vector)
 234{
 235        printk("Unable to handle exception at EA =0x%x, vector 0x%x",
 236               ea, vector);
 237        die("Oops", regs, 9);
 238}
 239
 240void __init trap_init(void)
 241{
 242        /* Nothing needs to be done */
 243}
 244
 245asmlinkage void do_trap(struct pt_regs *regs, unsigned long address)
 246{
 247        force_sig_fault(SIGTRAP, TRAP_TRACE, (void __user *)address);
 248
 249        regs->pc += 4;
 250}
 251
 252asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address)
 253{
 254        if (user_mode(regs)) {
 255                /* Send a SIGBUS */
 256                force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)address);
 257        } else {
 258                printk("KERNEL: Unaligned Access 0x%.8lx\n", address);
 259                show_registers(regs);
 260                die("Die:", regs, address);
 261        }
 262
 263}
 264
 265asmlinkage void do_bus_fault(struct pt_regs *regs, unsigned long address)
 266{
 267        if (user_mode(regs)) {
 268                /* Send a SIGBUS */
 269                force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address);
 270        } else {                /* Kernel mode */
 271                printk("KERNEL: Bus error (SIGBUS) 0x%.8lx\n", address);
 272                show_registers(regs);
 273                die("Die:", regs, address);
 274        }
 275}
 276
 277static inline int in_delay_slot(struct pt_regs *regs)
 278{
 279#ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX
 280        /* No delay slot flag, do the old way */
 281        unsigned int op, insn;
 282
 283        insn = *((unsigned int *)regs->pc);
 284        op = insn >> 26;
 285        switch (op) {
 286        case 0x00: /* l.j */
 287        case 0x01: /* l.jal */
 288        case 0x03: /* l.bnf */
 289        case 0x04: /* l.bf */
 290        case 0x11: /* l.jr */
 291        case 0x12: /* l.jalr */
 292                return 1;
 293        default:
 294                return 0;
 295        }
 296#else
 297        return mfspr(SPR_SR) & SPR_SR_DSX;
 298#endif
 299}
 300
 301static inline void adjust_pc(struct pt_regs *regs, unsigned long address)
 302{
 303        int displacement;
 304        unsigned int rb, op, jmp;
 305
 306        if (unlikely(in_delay_slot(regs))) {
 307                /* In delay slot, instruction at pc is a branch, simulate it */
 308                jmp = *((unsigned int *)regs->pc);
 309
 310                displacement = sign_extend32(((jmp) & 0x3ffffff) << 2, 27);
 311                rb = (jmp & 0x0000ffff) >> 11;
 312                op = jmp >> 26;
 313
 314                switch (op) {
 315                case 0x00: /* l.j */
 316                        regs->pc += displacement;
 317                        return;
 318                case 0x01: /* l.jal */
 319                        regs->pc += displacement;
 320                        regs->gpr[9] = regs->pc + 8;
 321                        return;
 322                case 0x03: /* l.bnf */
 323                        if (regs->sr & SPR_SR_F)
 324                                regs->pc += 8;
 325                        else
 326                                regs->pc += displacement;
 327                        return;
 328                case 0x04: /* l.bf */
 329                        if (regs->sr & SPR_SR_F)
 330                                regs->pc += displacement;
 331                        else
 332                                regs->pc += 8;
 333                        return;
 334                case 0x11: /* l.jr */
 335                        regs->pc = regs->gpr[rb];
 336                        return;
 337                case 0x12: /* l.jalr */
 338                        regs->pc = regs->gpr[rb];
 339                        regs->gpr[9] = regs->pc + 8;
 340                        return;
 341                default:
 342                        break;
 343                }
 344        } else {
 345                regs->pc += 4;
 346        }
 347}
 348
 349static inline void simulate_lwa(struct pt_regs *regs, unsigned long address,
 350                                unsigned int insn)
 351{
 352        unsigned int ra, rd;
 353        unsigned long value;
 354        unsigned long orig_pc;
 355        long imm;
 356
 357        const struct exception_table_entry *entry;
 358
 359        orig_pc = regs->pc;
 360        adjust_pc(regs, address);
 361
 362        ra = (insn >> 16) & 0x1f;
 363        rd = (insn >> 21) & 0x1f;
 364        imm = (short)insn;
 365        lwa_addr = (unsigned long __user *)(regs->gpr[ra] + imm);
 366
 367        if ((unsigned long)lwa_addr & 0x3) {
 368                do_unaligned_access(regs, address);
 369                return;
 370        }
 371
 372        if (get_user(value, lwa_addr)) {
 373                if (user_mode(regs)) {
 374                        force_sig(SIGSEGV);
 375                        return;
 376                }
 377
 378                if ((entry = search_exception_tables(orig_pc))) {
 379                        regs->pc = entry->fixup;
 380                        return;
 381                }
 382
 383                /* kernel access in kernel space, load it directly */
 384                value = *((unsigned long *)lwa_addr);
 385        }
 386
 387        lwa_flag = 1;
 388        regs->gpr[rd] = value;
 389}
 390
 391static inline void simulate_swa(struct pt_regs *regs, unsigned long address,
 392                                unsigned int insn)
 393{
 394        unsigned long __user *vaddr;
 395        unsigned long orig_pc;
 396        unsigned int ra, rb;
 397        long imm;
 398
 399        const struct exception_table_entry *entry;
 400
 401        orig_pc = regs->pc;
 402        adjust_pc(regs, address);
 403
 404        ra = (insn >> 16) & 0x1f;
 405        rb = (insn >> 11) & 0x1f;
 406        imm = (short)(((insn & 0x2200000) >> 10) | (insn & 0x7ff));
 407        vaddr = (unsigned long __user *)(regs->gpr[ra] + imm);
 408
 409        if (!lwa_flag || vaddr != lwa_addr) {
 410                regs->sr &= ~SPR_SR_F;
 411                return;
 412        }
 413
 414        if ((unsigned long)vaddr & 0x3) {
 415                do_unaligned_access(regs, address);
 416                return;
 417        }
 418
 419        if (put_user(regs->gpr[rb], vaddr)) {
 420                if (user_mode(regs)) {
 421                        force_sig(SIGSEGV);
 422                        return;
 423                }
 424
 425                if ((entry = search_exception_tables(orig_pc))) {
 426                        regs->pc = entry->fixup;
 427                        return;
 428                }
 429
 430                /* kernel access in kernel space, store it directly */
 431                *((unsigned long *)vaddr) = regs->gpr[rb];
 432        }
 433
 434        lwa_flag = 0;
 435        regs->sr |= SPR_SR_F;
 436}
 437
 438#define INSN_LWA        0x1b
 439#define INSN_SWA        0x33
 440
 441asmlinkage void do_illegal_instruction(struct pt_regs *regs,
 442                                       unsigned long address)
 443{
 444        unsigned int op;
 445        unsigned int insn = *((unsigned int *)address);
 446
 447        op = insn >> 26;
 448
 449        switch (op) {
 450        case INSN_LWA:
 451                simulate_lwa(regs, address, insn);
 452                return;
 453
 454        case INSN_SWA:
 455                simulate_swa(regs, address, insn);
 456                return;
 457
 458        default:
 459                break;
 460        }
 461
 462        if (user_mode(regs)) {
 463                /* Send a SIGILL */
 464                force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)address);
 465        } else {                /* Kernel mode */
 466                printk("KERNEL: Illegal instruction (SIGILL) 0x%.8lx\n",
 467                       address);
 468                show_registers(regs);
 469                die("Die:", regs, address);
 470        }
 471}
 472