linux/arch/avr32/kernel/traps.c
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   1/*
   2 * Copyright (C) 2004-2006 Atmel Corporation
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 */
   8
   9#include <linux/bug.h>
  10#include <linux/init.h>
  11#include <linux/kallsyms.h>
  12#include <linux/kdebug.h>
  13#include <linux/module.h>
  14#include <linux/notifier.h>
  15#include <linux/sched.h>
  16#include <linux/uaccess.h>
  17
  18#include <asm/addrspace.h>
  19#include <asm/mmu_context.h>
  20#include <asm/ocd.h>
  21#include <asm/sysreg.h>
  22#include <asm/traps.h>
  23
  24static DEFINE_SPINLOCK(die_lock);
  25
  26void NORET_TYPE die(const char *str, struct pt_regs *regs, long err)
  27{
  28        static int die_counter;
  29
  30        console_verbose();
  31        spin_lock_irq(&die_lock);
  32        bust_spinlocks(1);
  33
  34        printk(KERN_ALERT "Oops: %s, sig: %ld [#%d]\n" KERN_EMERG,
  35               str, err, ++die_counter);
  36#ifdef CONFIG_PREEMPT
  37        printk("PREEMPT ");
  38#endif
  39#ifdef CONFIG_FRAME_POINTER
  40        printk("FRAME_POINTER ");
  41#endif
  42        if (current_cpu_data.features & AVR32_FEATURE_OCD) {
  43                unsigned long did = ocd_read(DID);
  44                printk("chip: 0x%03lx:0x%04lx rev %lu\n",
  45                       (did >> 1) & 0x7ff,
  46                       (did >> 12) & 0x7fff,
  47                       (did >> 28) & 0xf);
  48        } else {
  49                printk("cpu: arch %u r%u / core %u r%u\n",
  50                       current_cpu_data.arch_type,
  51                       current_cpu_data.arch_revision,
  52                       current_cpu_data.cpu_type,
  53                       current_cpu_data.cpu_revision);
  54        }
  55
  56        print_modules();
  57        show_regs_log_lvl(regs, KERN_EMERG);
  58        show_stack_log_lvl(current, regs->sp, regs, KERN_EMERG);
  59        bust_spinlocks(0);
  60        add_taint(TAINT_DIE);
  61        spin_unlock_irq(&die_lock);
  62
  63        if (in_interrupt())
  64                panic("Fatal exception in interrupt");
  65
  66        if (panic_on_oops)
  67                panic("Fatal exception");
  68
  69        do_exit(err);
  70}
  71
  72void _exception(long signr, struct pt_regs *regs, int code,
  73                unsigned long addr)
  74{
  75        siginfo_t info;
  76
  77        if (!user_mode(regs))
  78                die("Unhandled exception in kernel mode", regs, signr);
  79
  80        memset(&info, 0, sizeof(info));
  81        info.si_signo = signr;
  82        info.si_code = code;
  83        info.si_addr = (void __user *)addr;
  84        force_sig_info(signr, &info, current);
  85
  86        /*
  87         * Init gets no signals that it doesn't have a handler for.
  88         * That's all very well, but if it has caused a synchronous
  89         * exception and we ignore the resulting signal, it will just
  90         * generate the same exception over and over again and we get
  91         * nowhere.  Better to kill it and let the kernel panic.
  92         */
  93        if (is_global_init(current)) {
  94                __sighandler_t handler;
  95
  96                spin_lock_irq(&current->sighand->siglock);
  97                handler = current->sighand->action[signr-1].sa.sa_handler;
  98                spin_unlock_irq(&current->sighand->siglock);
  99                if (handler == SIG_DFL) {
 100                        /* init has generated a synchronous exception
 101                           and it doesn't have a handler for the signal */
 102                        printk(KERN_CRIT "init has generated signal %ld "
 103                               "but has no handler for it\n", signr);
 104                        do_exit(signr);
 105                }
 106        }
 107}
 108
 109asmlinkage void do_nmi(unsigned long ecr, struct pt_regs *regs)
 110{
 111        int ret;
 112
 113        nmi_enter();
 114
 115        ret = notify_die(DIE_NMI, "NMI", regs, 0, ecr, SIGINT);
 116        switch (ret) {
 117        case NOTIFY_OK:
 118        case NOTIFY_STOP:
 119                break;
 120        case NOTIFY_BAD:
 121                die("Fatal Non-Maskable Interrupt", regs, SIGINT);
 122        default:
 123                printk(KERN_ALERT "Got NMI, but nobody cared. Disabling...\n");
 124                nmi_disable();
 125                break;
 126        }
 127        nmi_exit();
 128}
 129
 130asmlinkage void do_critical_exception(unsigned long ecr, struct pt_regs *regs)
 131{
 132        die("Critical exception", regs, SIGKILL);
 133}
 134
 135asmlinkage void do_address_exception(unsigned long ecr, struct pt_regs *regs)
 136{
 137        _exception(SIGBUS, regs, BUS_ADRALN, regs->pc);
 138}
 139
 140/* This way of handling undefined instructions is stolen from ARM */
 141static LIST_HEAD(undef_hook);
 142static DEFINE_SPINLOCK(undef_lock);
 143
 144void register_undef_hook(struct undef_hook *hook)
 145{
 146        spin_lock_irq(&undef_lock);
 147        list_add(&hook->node, &undef_hook);
 148        spin_unlock_irq(&undef_lock);
 149}
 150
 151void unregister_undef_hook(struct undef_hook *hook)
 152{
 153        spin_lock_irq(&undef_lock);
 154        list_del(&hook->node);
 155        spin_unlock_irq(&undef_lock);
 156}
 157
 158static int do_cop_absent(u32 insn)
 159{
 160        int cop_nr;
 161        u32 cpucr;
 162
 163        if ((insn & 0xfdf00000) == 0xf1900000)
 164                /* LDC0 */
 165                cop_nr = 0;
 166        else
 167                cop_nr = (insn >> 13) & 0x7;
 168
 169        /* Try enabling the coprocessor */
 170        cpucr = sysreg_read(CPUCR);
 171        cpucr |= (1 << (24 + cop_nr));
 172        sysreg_write(CPUCR, cpucr);
 173
 174        cpucr = sysreg_read(CPUCR);
 175        if (!(cpucr & (1 << (24 + cop_nr))))
 176                return -ENODEV;
 177
 178        return 0;
 179}
 180
 181#ifdef CONFIG_BUG
 182int is_valid_bugaddr(unsigned long pc)
 183{
 184        unsigned short opcode;
 185
 186        if (pc < PAGE_OFFSET)
 187                return 0;
 188        if (probe_kernel_address((u16 *)pc, opcode))
 189                return 0;
 190
 191        return opcode == AVR32_BUG_OPCODE;
 192}
 193#endif
 194
 195asmlinkage void do_illegal_opcode(unsigned long ecr, struct pt_regs *regs)
 196{
 197        u32 insn;
 198        struct undef_hook *hook;
 199        void __user *pc;
 200        long code;
 201
 202#ifdef CONFIG_BUG
 203        if (!user_mode(regs) && (ecr == ECR_ILLEGAL_OPCODE)) {
 204                enum bug_trap_type type;
 205
 206                type = report_bug(regs->pc, regs);
 207                switch (type) {
 208                case BUG_TRAP_TYPE_NONE:
 209                        break;
 210                case BUG_TRAP_TYPE_WARN:
 211                        regs->pc += 2;
 212                        return;
 213                case BUG_TRAP_TYPE_BUG:
 214                        die("Kernel BUG", regs, SIGKILL);
 215                }
 216        }
 217#endif
 218
 219        local_irq_enable();
 220
 221        if (user_mode(regs)) {
 222                pc = (void __user *)instruction_pointer(regs);
 223                if (get_user(insn, (u32 __user *)pc))
 224                        goto invalid_area;
 225
 226                if (ecr == ECR_COPROC_ABSENT && !do_cop_absent(insn))
 227                        return;
 228
 229                spin_lock_irq(&undef_lock);
 230                list_for_each_entry(hook, &undef_hook, node) {
 231                        if ((insn & hook->insn_mask) == hook->insn_val) {
 232                                if (hook->fn(regs, insn) == 0) {
 233                                        spin_unlock_irq(&undef_lock);
 234                                        return;
 235                                }
 236                        }
 237                }
 238                spin_unlock_irq(&undef_lock);
 239        }
 240
 241        switch (ecr) {
 242        case ECR_PRIVILEGE_VIOLATION:
 243                code = ILL_PRVOPC;
 244                break;
 245        case ECR_COPROC_ABSENT:
 246                code = ILL_COPROC;
 247                break;
 248        default:
 249                code = ILL_ILLOPC;
 250                break;
 251        }
 252
 253        _exception(SIGILL, regs, code, regs->pc);
 254        return;
 255
 256invalid_area:
 257        _exception(SIGSEGV, regs, SEGV_MAPERR, regs->pc);
 258}
 259
 260asmlinkage void do_fpe(unsigned long ecr, struct pt_regs *regs)
 261{
 262        /* We have no FPU yet */
 263        _exception(SIGILL, regs, ILL_COPROC, regs->pc);
 264}
 265
 266
 267void __init trap_init(void)
 268{
 269
 270}
 271