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