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",
  36                str, err, ++die_counter);
  37
  38         printk(KERN_EMERG);
  39
  40 #ifdef CONFIG_PREEMPT
  41         printk(KERN_CONT "PREEMPT ");
  42 #endif
  43 #ifdef CONFIG_FRAME_POINTER
  44         printk(KERN_CONT "FRAME_POINTER ");
  45 #endif
  46         if (current_cpu_data.features & AVR32_FEATURE_OCD) {
  47                 unsigned long did = ocd_read(DID);
  48                 printk(KERN_CONT "chip: 0x%03lx:0x%04lx rev %lu\n",
  49                        (did >> 1) & 0x7ff,
  50                        (did >> 12) & 0x7fff,
  51                        (did >> 28) & 0xf);
  52         } else {
  53                 printk(KERN_CONT "cpu: arch %u r%u / core %u r%u\n",
  54                        current_cpu_data.arch_type,
  55                        current_cpu_data.arch_revision,
  56                        current_cpu_data.cpu_type,
  57                        current_cpu_data.cpu_revision);
  58         }
  59
  60         print_modules();
  61         show_regs_log_lvl(regs, KERN_EMERG);
  62         show_stack_log_lvl(current, regs->sp, regs, KERN_EMERG);
  63         bust_spinlocks(0);
  64         add_taint(TAINT_DIE);
  65         spin_unlock_irq(&die_lock);
  66
  67         if (in_interrupt())
  68                 panic("Fatal exception in interrupt");
  69
  70         if (panic_on_oops)
  71                 panic("Fatal exception");
  72
  73         do_exit(err);
  74 }
  75
  76 void _exception(long signr, struct pt_regs *regs, int code,
  77                 unsigned long addr)
  78 {
  79         siginfo_t info;
  80
  81         if (!user_mode(regs)) {
  82                 const struct exception_table_entry *fixup;
  83
  84                 /* Are we prepared to handle this kernel fault? */
  85                 fixup = search_exception_tables(regs->pc);
  86                 if (fixup) {
  87                         regs->pc = fixup->fixup;
  88                         return;
  89                 }
  90                 die("Unhandled exception in kernel mode", regs, signr);
  91         }
  92
  93         memset(&info, 0, sizeof(info));
  94         info.si_signo = signr;
  95         info.si_code = code;
  96         info.si_addr = (void __user *)addr;
  97         force_sig_info(signr, &info, current);
  98
  99         /*
 100          * Init gets no signals that it doesn't have a handler for.
 101          * That's all very well, but if it has caused a synchronous
 102          * exception and we ignore the resulting signal, it will just
 103          * generate the same exception over and over again and we get
 104          * nowhere.  Better to kill it and let the kernel panic.
 105          */
 106         if (is_global_init(current)) {
 107                 __sighandler_t handler;
 108
 109                 spin_lock_irq(&current->sighand->siglock);
 110                 handler = current->sighand->action[signr-1].sa.sa_handler;
 111                 spin_unlock_irq(&current->sighand->siglock);
 112                 if (handler == SIG_DFL) {
 113                         /* init has generated a synchronous exception
 114                            and it doesn't have a handler for the signal */
 115                         printk(KERN_CRIT "init has generated signal %ld "
 116                                "but has no handler for it\n", signr);
 117                         do_exit(signr);
 118                 }
 119         }
 120 }
 121
 122 asmlinkage void do_nmi(unsigned long ecr, struct pt_regs *regs)
 123 {
 124         int ret;
 125
 126         nmi_enter();
 127
 128         ret = notify_die(DIE_NMI, "NMI", regs, 0, ecr, SIGINT);
 129         switch (ret) {
 130         case NOTIFY_OK:
 131         case NOTIFY_STOP:
 132                 break;
 133         case NOTIFY_BAD:
 134                 die("Fatal Non-Maskable Interrupt", regs, SIGINT);
 135         default:
 136                 printk(KERN_ALERT "Got NMI, but nobody cared. Disabling...\n");
 137                 nmi_disable();
 138                 break;
 139         }
 140         nmi_exit();
 141 }
 142
 143 asmlinkage void do_critical_exception(unsigned long ecr, struct pt_regs *regs)
 144 {
 145         die("Critical exception", regs, SIGKILL);
 146 }
 147
 148 asmlinkage void do_address_exception(unsigned long ecr, struct pt_regs *regs)
 149 {
 150         _exception(SIGBUS, regs, BUS_ADRALN, regs->pc);
 151 }
 152
 153 /* This way of handling undefined instructions is stolen from ARM */
 154 static LIST_HEAD(undef_hook);
 155 static DEFINE_SPINLOCK(undef_lock);
 156
 157 void register_undef_hook(struct undef_hook *hook)
 158 {
 159         spin_lock_irq(&undef_lock);
 160         list_add(&hook->node, &undef_hook);
 161         spin_unlock_irq(&undef_lock);
 162 }
 163
 164 void unregister_undef_hook(struct undef_hook *hook)
 165 {
 166         spin_lock_irq(&undef_lock);
 167         list_del(&hook->node);
 168         spin_unlock_irq(&undef_lock);
 169 }
 170
 171 static int do_cop_absent(u32 insn)
 172 {
 173         int cop_nr;
 174         u32 cpucr;
 175
 176         if ((insn & 0xfdf00000) == 0xf1900000)
 177                 /* LDC0 */
 178                 cop_nr = 0;
 179         else
 180                 cop_nr = (insn >> 13) & 0x7;
 181
 182         /* Try enabling the coprocessor */
 183         cpucr = sysreg_read(CPUCR);
 184         cpucr |= (1 << (24 + cop_nr));
 185         sysreg_write(CPUCR, cpucr);
 186
 187         cpucr = sysreg_read(CPUCR);
 188         if (!(cpucr & (1 << (24 + cop_nr))))
 189                 return -ENODEV;
 190
 191         return 0;
 192 }
 193
 194 #ifdef CONFIG_BUG
 195 int is_valid_bugaddr(unsigned long pc)
 196 {
 197         unsigned short opcode;
 198
 199         if (pc < PAGE_OFFSET)
 200                 return 0;
 201         if (probe_kernel_address((u16 *)pc, opcode))
 202                 return 0;
 203
 204         return opcode == AVR32_BUG_OPCODE;
 205 }
 206 #endif
 207
 208 asmlinkage void do_illegal_opcode(unsigned long ecr, struct pt_regs *regs)
 209 {
 210         u32 insn;
 211         struct undef_hook *hook;
 212         void __user *pc;
 213         long code;
 214
 215 #ifdef CONFIG_BUG
 216         if (!user_mode(regs) && (ecr == ECR_ILLEGAL_OPCODE)) {
 217                 enum bug_trap_type type;
 218
 219                 type = report_bug(regs->pc, regs);
 220                 switch (type) {
 221                 case BUG_TRAP_TYPE_NONE:
 222                         break;
 223                 case BUG_TRAP_TYPE_WARN:
 224                         regs->pc += 2;
 225                         return;
 226                 case BUG_TRAP_TYPE_BUG:
 227                         die("Kernel BUG", regs, SIGKILL);
 228                 }
 229         }
 230 #endif
 231
 232         local_irq_enable();
 233
 234         if (user_mode(regs)) {
 235                 pc = (void __user *)instruction_pointer(regs);
 236                 if (get_user(insn, (u32 __user *)pc))
 237                         goto invalid_area;
 238
 239                 if (ecr == ECR_COPROC_ABSENT && !do_cop_absent(insn))
 240                         return;
 241
 242                 spin_lock_irq(&undef_lock);
 243                 list_for_each_entry(hook, &undef_hook, node) {
 244                         if ((insn & hook->insn_mask) == hook->insn_val) {
 245                                 if (hook->fn(regs, insn) == 0) {
 246                                         spin_unlock_irq(&undef_lock);
 247                                         return;
 248                                 }
 249                         }
 250                 }
 251                 spin_unlock_irq(&undef_lock);
 252         }
 253
 254         switch (ecr) {
 255         case ECR_PRIVILEGE_VIOLATION:
 256                 code = ILL_PRVOPC;
 257                 break;
 258         case ECR_COPROC_ABSENT:
 259                 code = ILL_COPROC;
 260                 break;
 261         default:
 262                 code = ILL_ILLOPC;
 263                 break;
 264         }
 265
 266         _exception(SIGILL, regs, code, regs->pc);
 267         return;
 268
 269 invalid_area:
 270         _exception(SIGSEGV, regs, SEGV_MAPERR, regs->pc);
 271 }
 272
 273 asmlinkage void do_fpe(unsigned long ecr, struct pt_regs *regs)
 274 {
 275         /* We have no FPU yet */
 276         _exception(SIGILL, regs, ILL_COPROC, regs->pc);
 277 }
 278
 279
 280 void __init trap_init(void)
 281 {
 282
 283 }