arch/avr32/kernel/traps.c

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