linux/arch/nds32/kernel/traps.c
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   1// SPDX-License-Identifier: GPL-2.0
   2// Copyright (C) 2005-2017 Andes Technology Corporation
   3
   4#include <linux/module.h>
   5#include <linux/personality.h>
   6#include <linux/kallsyms.h>
   7#include <linux/hardirq.h>
   8#include <linux/kdebug.h>
   9#include <linux/sched/task_stack.h>
  10#include <linux/uaccess.h>
  11
  12#include <asm/proc-fns.h>
  13#include <asm/unistd.h>
  14
  15#include <linux/ptrace.h>
  16#include <nds32_intrinsic.h>
  17
  18extern void show_pte(struct mm_struct *mm, unsigned long addr);
  19
  20/*
  21 * Dump out the contents of some memory nicely...
  22 */
  23void dump_mem(const char *lvl, unsigned long bottom, unsigned long top)
  24{
  25        unsigned long first;
  26        mm_segment_t fs;
  27        int i;
  28
  29        /*
  30         * We need to switch to kernel mode so that we can use __get_user
  31         * to safely read from kernel space.  Note that we now dump the
  32         * code first, just in case the backtrace kills us.
  33         */
  34        fs = get_fs();
  35        set_fs(KERNEL_DS);
  36
  37        pr_emerg("%s(0x%08lx to 0x%08lx)\n", lvl, bottom, top);
  38
  39        for (first = bottom & ~31; first < top; first += 32) {
  40                unsigned long p;
  41                char str[sizeof(" 12345678") * 8 + 1];
  42
  43                memset(str, ' ', sizeof(str));
  44                str[sizeof(str) - 1] = '\0';
  45
  46                for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
  47                        if (p >= bottom && p < top) {
  48                                unsigned long val;
  49                                if (__get_user(val, (unsigned long *)p) == 0)
  50                                        sprintf(str + i * 9, " %08lx", val);
  51                                else
  52                                        sprintf(str + i * 9, " ????????");
  53                        }
  54                }
  55                pr_emerg("%s%04lx:%s\n", lvl, first & 0xffff, str);
  56        }
  57
  58        set_fs(fs);
  59}
  60
  61EXPORT_SYMBOL(dump_mem);
  62
  63static void dump_instr(struct pt_regs *regs)
  64{
  65        unsigned long addr = instruction_pointer(regs);
  66        mm_segment_t fs;
  67        char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
  68        int i;
  69
  70        return;
  71        /*
  72         * We need to switch to kernel mode so that we can use __get_user
  73         * to safely read from kernel space.  Note that we now dump the
  74         * code first, just in case the backtrace kills us.
  75         */
  76        fs = get_fs();
  77        set_fs(KERNEL_DS);
  78
  79        pr_emerg("Code: ");
  80        for (i = -4; i < 1; i++) {
  81                unsigned int val, bad;
  82
  83                bad = __get_user(val, &((u32 *) addr)[i]);
  84
  85                if (!bad) {
  86                        p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
  87                } else {
  88                        p += sprintf(p, "bad PC value");
  89                        break;
  90                }
  91        }
  92        pr_emerg("Code: %s\n", str);
  93
  94        set_fs(fs);
  95}
  96
  97#ifdef CONFIG_FUNCTION_GRAPH_TRACER
  98#include <linux/ftrace.h>
  99static void
 100get_real_ret_addr(unsigned long *addr, struct task_struct *tsk, int *graph)
 101{
 102        if (*addr == (unsigned long)return_to_handler) {
 103                int index = tsk->curr_ret_stack;
 104
 105                if (tsk->ret_stack && index >= *graph) {
 106                        index -= *graph;
 107                        *addr = tsk->ret_stack[index].ret;
 108                        (*graph)++;
 109                }
 110        }
 111}
 112#else
 113static inline void
 114get_real_ret_addr(unsigned long *addr, struct task_struct *tsk, int *graph)
 115{
 116}
 117#endif
 118
 119#define LOOP_TIMES (100)
 120static void __dump(struct task_struct *tsk, unsigned long *base_reg)
 121{
 122        unsigned long ret_addr;
 123        int cnt = LOOP_TIMES, graph = 0;
 124        pr_emerg("Call Trace:\n");
 125        if (!IS_ENABLED(CONFIG_FRAME_POINTER)) {
 126                while (!kstack_end(base_reg)) {
 127                        ret_addr = *base_reg++;
 128                        if (__kernel_text_address(ret_addr)) {
 129                                get_real_ret_addr(&ret_addr, tsk, &graph);
 130                                print_ip_sym(ret_addr);
 131                        }
 132                        if (--cnt < 0)
 133                                break;
 134                }
 135        } else {
 136                while (!kstack_end((void *)base_reg) &&
 137                       !((unsigned long)base_reg & 0x3) &&
 138                       ((unsigned long)base_reg >= TASK_SIZE)) {
 139                        unsigned long next_fp;
 140#if !defined(NDS32_ABI_2)
 141                        ret_addr = base_reg[0];
 142                        next_fp = base_reg[1];
 143#else
 144                        ret_addr = base_reg[-1];
 145                        next_fp = base_reg[FP_OFFSET];
 146#endif
 147                        if (__kernel_text_address(ret_addr)) {
 148                                get_real_ret_addr(&ret_addr, tsk, &graph);
 149                                print_ip_sym(ret_addr);
 150                        }
 151                        if (--cnt < 0)
 152                                break;
 153                        base_reg = (unsigned long *)next_fp;
 154                }
 155        }
 156        pr_emerg("\n");
 157}
 158
 159void show_stack(struct task_struct *tsk, unsigned long *sp)
 160{
 161        unsigned long *base_reg;
 162
 163        if (!tsk)
 164                tsk = current;
 165        if (!IS_ENABLED(CONFIG_FRAME_POINTER)) {
 166                if (tsk != current)
 167                        base_reg = (unsigned long *)(tsk->thread.cpu_context.sp);
 168                else
 169                        __asm__ __volatile__("\tori\t%0, $sp, #0\n":"=r"(base_reg));
 170        } else {
 171                if (tsk != current)
 172                        base_reg = (unsigned long *)(tsk->thread.cpu_context.fp);
 173                else
 174                        __asm__ __volatile__("\tori\t%0, $fp, #0\n":"=r"(base_reg));
 175        }
 176        __dump(tsk, base_reg);
 177        barrier();
 178}
 179
 180DEFINE_SPINLOCK(die_lock);
 181
 182/*
 183 * This function is protected against re-entrancy.
 184 */
 185void die(const char *str, struct pt_regs *regs, int err)
 186{
 187        struct task_struct *tsk = current;
 188        static int die_counter;
 189
 190        console_verbose();
 191        spin_lock_irq(&die_lock);
 192        bust_spinlocks(1);
 193
 194        pr_emerg("Internal error: %s: %x [#%d]\n", str, err, ++die_counter);
 195        print_modules();
 196        pr_emerg("CPU: %i\n", smp_processor_id());
 197        show_regs(regs);
 198        pr_emerg("Process %s (pid: %d, stack limit = 0x%p)\n",
 199                 tsk->comm, tsk->pid, task_thread_info(tsk) + 1);
 200
 201        if (!user_mode(regs) || in_interrupt()) {
 202                dump_mem("Stack: ", regs->sp,
 203                         THREAD_SIZE + (unsigned long)task_thread_info(tsk));
 204                dump_instr(regs);
 205                dump_stack();
 206        }
 207
 208        bust_spinlocks(0);
 209        spin_unlock_irq(&die_lock);
 210        do_exit(SIGSEGV);
 211}
 212
 213EXPORT_SYMBOL(die);
 214
 215void die_if_kernel(const char *str, struct pt_regs *regs, int err)
 216{
 217        if (user_mode(regs))
 218                return;
 219
 220        die(str, regs, err);
 221}
 222
 223int bad_syscall(int n, struct pt_regs *regs)
 224{
 225        if (current->personality != PER_LINUX) {
 226                send_sig(SIGSEGV, current, 1);
 227                return regs->uregs[0];
 228        }
 229
 230        force_sig_fault(SIGILL, ILL_ILLTRP,
 231                        (void __user *)instruction_pointer(regs) - 4, current);
 232        die_if_kernel("Oops - bad syscall", regs, n);
 233        return regs->uregs[0];
 234}
 235
 236void __pte_error(const char *file, int line, unsigned long val)
 237{
 238        pr_emerg("%s:%d: bad pte %08lx.\n", file, line, val);
 239}
 240
 241void __pmd_error(const char *file, int line, unsigned long val)
 242{
 243        pr_emerg("%s:%d: bad pmd %08lx.\n", file, line, val);
 244}
 245
 246void __pgd_error(const char *file, int line, unsigned long val)
 247{
 248        pr_emerg("%s:%d: bad pgd %08lx.\n", file, line, val);
 249}
 250
 251extern char *exception_vector, *exception_vector_end;
 252void __init trap_init(void)
 253{
 254        return;
 255}
 256
 257void __init early_trap_init(void)
 258{
 259        unsigned long ivb = 0;
 260        unsigned long base = PAGE_OFFSET;
 261
 262        memcpy((unsigned long *)base, (unsigned long *)&exception_vector,
 263               ((unsigned long)&exception_vector_end -
 264                (unsigned long)&exception_vector));
 265        ivb = __nds32__mfsr(NDS32_SR_IVB);
 266        /* Check platform support. */
 267        if (((ivb & IVB_mskNIVIC) >> IVB_offNIVIC) < 2)
 268                panic
 269                    ("IVIC mode is not allowed on the platform with interrupt controller\n");
 270        __nds32__mtsr((ivb & ~IVB_mskESZ) | (IVB_valESZ16 << IVB_offESZ) |
 271                      IVB_BASE, NDS32_SR_IVB);
 272        __nds32__mtsr(INT_MASK_INITAIAL_VAL, NDS32_SR_INT_MASK);
 273
 274        /*
 275         * 0x800 = 128 vectors * 16byte.
 276         * It should be enough to flush a page.
 277         */
 278        cpu_cache_wbinval_page(base, true);
 279}
 280
 281void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
 282                  int error_code, int si_code)
 283{
 284        tsk->thread.trap_no = ENTRY_DEBUG_RELATED;
 285        tsk->thread.error_code = error_code;
 286
 287        force_sig_fault(SIGTRAP, si_code,
 288                        (void __user *)instruction_pointer(regs), tsk);
 289}
 290
 291void do_debug_trap(unsigned long entry, unsigned long addr,
 292                   unsigned long type, struct pt_regs *regs)
 293{
 294        if (notify_die(DIE_OOPS, "Oops", regs, addr, type, SIGTRAP)
 295            == NOTIFY_STOP)
 296                return;
 297
 298        if (user_mode(regs)) {
 299                /* trap_signal */
 300                send_sigtrap(current, regs, 0, TRAP_BRKPT);
 301        } else {
 302                /* kernel_trap */
 303                if (!fixup_exception(regs))
 304                        die("unexpected kernel_trap", regs, 0);
 305        }
 306}
 307
 308void unhandled_interruption(struct pt_regs *regs)
 309{
 310        pr_emerg("unhandled_interruption\n");
 311        show_regs(regs);
 312        if (!user_mode(regs))
 313                do_exit(SIGKILL);
 314        force_sig(SIGKILL, current);
 315}
 316
 317void unhandled_exceptions(unsigned long entry, unsigned long addr,
 318                          unsigned long type, struct pt_regs *regs)
 319{
 320        pr_emerg("Unhandled Exception: entry: %lx addr:%lx itype:%lx\n", entry,
 321                 addr, type);
 322        show_regs(regs);
 323        if (!user_mode(regs))
 324                do_exit(SIGKILL);
 325        force_sig(SIGKILL, current);
 326}
 327
 328extern int do_page_fault(unsigned long entry, unsigned long addr,
 329                         unsigned int error_code, struct pt_regs *regs);
 330
 331/*
 332 * 2:DEF dispatch for TLB MISC exception handler
 333*/
 334
 335void do_dispatch_tlb_misc(unsigned long entry, unsigned long addr,
 336                          unsigned long type, struct pt_regs *regs)
 337{
 338        type = type & (ITYPE_mskINST | ITYPE_mskETYPE);
 339        if ((type & ITYPE_mskETYPE) < 5) {
 340                /* Permission exceptions */
 341                do_page_fault(entry, addr, type, regs);
 342        } else
 343                unhandled_exceptions(entry, addr, type, regs);
 344}
 345
 346void do_revinsn(struct pt_regs *regs)
 347{
 348        pr_emerg("Reserved Instruction\n");
 349        show_regs(regs);
 350        if (!user_mode(regs))
 351                do_exit(SIGILL);
 352        force_sig(SIGILL, current);
 353}
 354
 355#ifdef CONFIG_ALIGNMENT_TRAP
 356extern int unalign_access_mode;
 357extern int do_unaligned_access(unsigned long addr, struct pt_regs *regs);
 358#endif
 359void do_dispatch_general(unsigned long entry, unsigned long addr,
 360                         unsigned long itype, struct pt_regs *regs,
 361                         unsigned long oipc)
 362{
 363        unsigned int swid = itype >> ITYPE_offSWID;
 364        unsigned long type = itype & (ITYPE_mskINST | ITYPE_mskETYPE);
 365        if (type == ETYPE_ALIGNMENT_CHECK) {
 366#ifdef CONFIG_ALIGNMENT_TRAP
 367                /* Alignment check */
 368                if (user_mode(regs) && unalign_access_mode) {
 369                        int ret;
 370                        ret = do_unaligned_access(addr, regs);
 371
 372                        if (ret == 0)
 373                                return;
 374
 375                        if (ret == -EFAULT)
 376                                pr_emerg
 377                                    ("Unhandled unaligned access exception\n");
 378                }
 379#endif
 380                do_page_fault(entry, addr, type, regs);
 381        } else if (type == ETYPE_RESERVED_INSTRUCTION) {
 382                /* Reserved instruction */
 383                do_revinsn(regs);
 384        } else if (type == ETYPE_TRAP && swid == SWID_RAISE_INTERRUPT_LEVEL) {
 385                /* trap, used on v3 EDM target debugging workaround */
 386                /*
 387                 * DIPC(OIPC) is passed as parameter before
 388                 * interrupt is enabled, so the DIPC will not be corrupted
 389                 * even though interrupts are coming in
 390                 */
 391                /*
 392                 * 1. update ipc
 393                 * 2. update pt_regs ipc with oipc
 394                 * 3. update pt_regs ipsw (clear DEX)
 395                 */
 396                __asm__ volatile ("mtsr %0, $IPC\n\t"::"r" (oipc));
 397                regs->ipc = oipc;
 398                if (regs->pipsw & PSW_mskDEX) {
 399                        pr_emerg
 400                            ("Nested Debug exception is possibly happened\n");
 401                        pr_emerg("ipc:%08x pipc:%08x\n",
 402                                 (unsigned int)regs->ipc,
 403                                 (unsigned int)regs->pipc);
 404                }
 405                do_debug_trap(entry, addr, itype, regs);
 406                regs->ipsw &= ~PSW_mskDEX;
 407        } else
 408                unhandled_exceptions(entry, addr, type, regs);
 409}
 410