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/init.h>
  11 #include <linux/kallsyms.h>
  12 #include <linux/module.h>
  13 #include <linux/notifier.h>
  14 #include <linux/sched.h>
  15 #include <linux/uaccess.h>
  16
  17 #include <asm/addrspace.h>
  18 #include <asm/mmu_context.h>
  19 #include <asm/ocd.h>
  20 #include <asm/sysreg.h>
  21 #include <asm/traps.h>
  22
  23 ATOMIC_NOTIFIER_HEAD(avr32_die_chain);
  24
  25 int register_die_notifier(struct notifier_block *nb)
  26 {
  27         return atomic_notifier_chain_register(&avr32_die_chain, nb);
  28 }
  29 EXPORT_SYMBOL(register_die_notifier);
  30
  31 int unregister_die_notifier(struct notifier_block *nb)
  32 {
  33         return atomic_notifier_chain_unregister(&avr32_die_chain, nb);
  34 }
  35 EXPORT_SYMBOL(unregister_die_notifier);
  36
  37 static DEFINE_SPINLOCK(die_lock);
  38
  39 void NORET_TYPE die(const char *str, struct pt_regs *regs, long err)
  40 {
  41         static int die_counter;
  42
  43         console_verbose();
  44         spin_lock_irq(&die_lock);
  45         bust_spinlocks(1);
  46
  47         printk(KERN_ALERT "Oops: %s, sig: %ld [#%d]\n" KERN_EMERG,
  48                str, err, ++die_counter);
  49 #ifdef CONFIG_PREEMPT
  50         printk("PREEMPT ");
  51 #endif
  52 #ifdef CONFIG_FRAME_POINTER
  53         printk("FRAME_POINTER ");
  54 #endif
  55         if (current_cpu_data.features & AVR32_FEATURE_OCD) {
  56                 unsigned long did = __mfdr(DBGREG_DID);
  57                 printk("chip: 0x%03lx:0x%04lx rev %lu\n",
  58                        (did >> 1) & 0x7ff,
  59                        (did >> 12) & 0x7fff,
  60                        (did >> 28) & 0xf);
  61         } else {
  62                 printk("cpu: arch %u r%u / core %u r%u\n",
  63                        current_cpu_data.arch_type,
  64                        current_cpu_data.arch_revision,
  65                        current_cpu_data.cpu_type,
  66                        current_cpu_data.cpu_revision);
  67         }
  68
  69         print_modules();
  70         show_regs_log_lvl(regs, KERN_EMERG);
  71         show_stack_log_lvl(current, regs->sp, regs, KERN_EMERG);
  72         bust_spinlocks(0);
  73         spin_unlock_irq(&die_lock);
  74
  75         if (in_interrupt())
  76                 panic("Fatal exception in interrupt");
  77
  78         if (panic_on_oops)
  79                 panic("Fatal exception");
  80
  81         do_exit(err);
  82 }
  83
  84 void _exception(long signr, struct pt_regs *regs, int code,
  85                 unsigned long addr)
  86 {
  87         siginfo_t info;
  88
  89         if (!user_mode(regs))
  90                 die("Unhandled exception in kernel mode", regs, signr);
  91
  92         memset(&info, 0, sizeof(info));
  93         info.si_signo = signr;
  94         info.si_code = code;
  95         info.si_addr = (void __user *)addr;
  96         force_sig_info(signr, &info, current);
  97
  98         /*
  99          * Init gets no signals that it doesn't have a handler for.
 100          * That's all very well, but if it has caused a synchronous
 101          * exception and we ignore the resulting signal, it will just
 102          * generate the same exception over and over again and we get
 103          * nowhere.  Better to kill it and let the kernel panic.
 104          */
 105         if (is_init(current)) {
 106                 __sighandler_t handler;
 107
 108                 spin_lock_irq(&current->sighand->siglock);
 109                 handler = current->sighand->action[signr-1].sa.sa_handler;
 110                 spin_unlock_irq(&current->sighand->siglock);
 111                 if (handler == SIG_DFL) {
 112                         /* init has generated a synchronous exception
 113                            and it doesn't have a handler for the signal */
 114                         printk(KERN_CRIT "init has generated signal %ld "
 115                                "but has no handler for it\n", signr);
 116                         do_exit(signr);
 117                 }
 118         }
 119 }
 120
 121 asmlinkage void do_nmi(unsigned long ecr, struct pt_regs *regs)
 122 {
 123         printk(KERN_ALERT "Got Non-Maskable Interrupt, dumping regs\n");
 124         show_regs_log_lvl(regs, KERN_ALERT);
 125         show_stack_log_lvl(current, regs->sp, regs, KERN_ALERT);
 126 }
 127
 128 asmlinkage void do_critical_exception(unsigned long ecr, struct pt_regs *regs)
 129 {
 130         die("Critical exception", regs, SIGKILL);
 131 }
 132
 133 asmlinkage void do_address_exception(unsigned long ecr, struct pt_regs *regs)
 134 {
 135         _exception(SIGBUS, regs, BUS_ADRALN, regs->pc);
 136 }
 137
 138 /* This way of handling undefined instructions is stolen from ARM */
 139 static LIST_HEAD(undef_hook);
 140 static spinlock_t undef_lock = SPIN_LOCK_UNLOCKED;
 141
 142 void register_undef_hook(struct undef_hook *hook)
 143 {
 144         spin_lock_irq(&undef_lock);
 145         list_add(&hook->node, &undef_hook);
 146         spin_unlock_irq(&undef_lock);
 147 }
 148
 149 void unregister_undef_hook(struct undef_hook *hook)
 150 {
 151         spin_lock_irq(&undef_lock);
 152         list_del(&hook->node);
 153         spin_unlock_irq(&undef_lock);
 154 }
 155
 156 static int do_cop_absent(u32 insn)
 157 {
 158         int cop_nr;
 159         u32 cpucr;
 160
 161         if ((insn & 0xfdf00000) == 0xf1900000)
 162                 /* LDC0 */
 163                 cop_nr = 0;
 164         else
 165                 cop_nr = (insn >> 13) & 0x7;
 166
 167         /* Try enabling the coprocessor */
 168         cpucr = sysreg_read(CPUCR);
 169         cpucr |= (1 << (24 + cop_nr));
 170         sysreg_write(CPUCR, cpucr);
 171
 172         cpucr = sysreg_read(CPUCR);
 173         if (!(cpucr & (1 << (24 + cop_nr))))
 174                 return -ENODEV;
 175
 176         return 0;
 177 }
 178
 179 int is_valid_bugaddr(unsigned long pc)
 180 {
 181         unsigned short opcode;
 182
 183         if (pc < PAGE_OFFSET)
 184                 return 0;
 185         if (probe_kernel_address((u16 *)pc, opcode))
 186                 return 0;
 187
 188         return opcode == AVR32_BUG_OPCODE;
 189 }
 190
 191 asmlinkage void do_illegal_opcode(unsigned long ecr, struct pt_regs *regs)
 192 {
 193         u32 insn;
 194         struct undef_hook *hook;
 195         void __user *pc;
 196         long code;
 197
 198         if (!user_mode(regs) && (ecr == ECR_ILLEGAL_OPCODE)) {
 199                 enum bug_trap_type type;
 200
 201                 type = report_bug(regs->pc);
 202                 switch (type) {
 203                 case BUG_TRAP_TYPE_NONE:
 204                         break;
 205                 case BUG_TRAP_TYPE_WARN:
 206                         regs->pc += 2;
 207                         return;
 208                 case BUG_TRAP_TYPE_BUG:
 209                         die("Kernel BUG", regs, SIGKILL);
 210                 }
 211         }
 212
 213         local_irq_enable();
 214
 215         if (user_mode(regs)) {
 216                 pc = (void __user *)instruction_pointer(regs);
 217                 if (get_user(insn, (u32 __user *)pc))
 218                         goto invalid_area;
 219
 220                 if (ecr == ECR_COPROC_ABSENT && !do_cop_absent(insn))
 221                         return;
 222
 223                 spin_lock_irq(&undef_lock);
 224                 list_for_each_entry(hook, &undef_hook, node) {
 225                         if ((insn & hook->insn_mask) == hook->insn_val) {
 226                                 if (hook->fn(regs, insn) == 0) {
 227                                         spin_unlock_irq(&undef_lock);
 228                                         return;
 229                                 }
 230                         }
 231                 }
 232                 spin_unlock_irq(&undef_lock);
 233         }
 234
 235         switch (ecr) {
 236         case ECR_PRIVILEGE_VIOLATION:
 237                 code = ILL_PRVOPC;
 238                 break;
 239         case ECR_COPROC_ABSENT:
 240                 code = ILL_COPROC;
 241                 break;
 242         default:
 243                 code = ILL_ILLOPC;
 244                 break;
 245         }
 246
 247         _exception(SIGILL, regs, code, regs->pc);
 248         return;
 249
 250 invalid_area:
 251         _exception(SIGSEGV, regs, SEGV_MAPERR, regs->pc);
 252 }
 253
 254 asmlinkage void do_fpe(unsigned long ecr, struct pt_regs *regs)
 255 {
 256         /* We have no FPU yet */
 257         _exception(SIGILL, regs, ILL_COPROC, regs->pc);
 258 }
 259
 260
 261 void __init trap_init(void)
 262 {
 263
 264 }