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/extable.h>
  15 #include <linux/module.h>       /* print_modules */
  16 #include <linux/notifier.h>
  17 #include <linux/sched.h>
  18 #include <linux/uaccess.h>
  19
  20 #include <asm/addrspace.h>
  21 #include <asm/mmu_context.h>
  22 #include <asm/ocd.h>
  23 #include <asm/sysreg.h>
  24 #include <asm/traps.h>
  25
  26 static DEFINE_SPINLOCK(die_lock);
  27
  28 void die(const char *str, struct pt_regs *regs, long err)
  29 {
  30         static int die_counter;
  31
  32         console_verbose();
  33         spin_lock_irq(&die_lock);
  34         bust_spinlocks(1);
  35
  36         printk(KERN_ALERT "Oops: %s, sig: %ld [#%d]\n",
  37                str, err, ++die_counter);
  38
  39         printk(KERN_EMERG);
  40
  41 #ifdef CONFIG_PREEMPT
  42         printk(KERN_CONT "PREEMPT ");
  43 #endif
  44 #ifdef CONFIG_FRAME_POINTER
  45         printk(KERN_CONT "FRAME_POINTER ");
  46 #endif
  47         if (current_cpu_data.features & AVR32_FEATURE_OCD) {
  48                 unsigned long did = ocd_read(DID);
  49                 printk(KERN_CONT "chip: 0x%03lx:0x%04lx rev %lu\n",
  50                        (did >> 1) & 0x7ff,
  51                        (did >> 12) & 0x7fff,
  52                        (did >> 28) & 0xf);
  53         } else {
  54                 printk(KERN_CONT "cpu: arch %u r%u / core %u r%u\n",
  55                        current_cpu_data.arch_type,
  56                        current_cpu_data.arch_revision,
  57                        current_cpu_data.cpu_type,
  58                        current_cpu_data.cpu_revision);
  59         }
  60
  61         print_modules();
  62         show_regs_log_lvl(regs, KERN_EMERG);
  63         show_stack_log_lvl(current, regs->sp, regs, KERN_EMERG);
  64         bust_spinlocks(0);
  65         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
  66         spin_unlock_irq(&die_lock);
  67
  68         if (in_interrupt())
  69                 panic("Fatal exception in interrupt");
  70
  71         if (panic_on_oops)
  72                 panic("Fatal exception");
  73
  74         do_exit(err);
  75 }
  76
  77 void _exception(long signr, struct pt_regs *regs, int code,
  78                 unsigned long addr)
  79 {
  80         siginfo_t info;
  81
  82         if (!user_mode(regs)) {
  83                 const struct exception_table_entry *fixup;
  84
  85                 /* Are we prepared to handle this kernel fault? */
  86                 fixup = search_exception_tables(regs->pc);
  87                 if (fixup) {
  88                         regs->pc = fixup->fixup;
  89                         return;
  90                 }
  91                 die("Unhandled exception in kernel mode", regs, signr);
  92         }
  93
  94         memset(&info, 0, sizeof(info));
  95         info.si_signo = signr;
  96         info.si_code = code;
  97         info.si_addr = (void __user *)addr;
  98         force_sig_info(signr, &info, current);
  99 }
 100
 101 asmlinkage void do_nmi(unsigned long ecr, struct pt_regs *regs)
 102 {
 103         int ret;
 104
 105         nmi_enter();
 106
 107         ret = notify_die(DIE_NMI, "NMI", regs, 0, ecr, SIGINT);
 108         switch (ret) {
 109         case NOTIFY_OK:
 110         case NOTIFY_STOP:
 111                 break;
 112         case NOTIFY_BAD:
 113                 die("Fatal Non-Maskable Interrupt", regs, SIGINT);
 114         default:
 115                 printk(KERN_ALERT "Got NMI, but nobody cared. Disabling...\n");
 116                 nmi_disable();
 117                 break;
 118         }
 119         nmi_exit();
 120 }
 121
 122 asmlinkage void do_critical_exception(unsigned long ecr, struct pt_regs *regs)
 123 {
 124         die("Critical exception", regs, SIGKILL);
 125 }
 126
 127 asmlinkage void do_address_exception(unsigned long ecr, struct pt_regs *regs)
 128 {
 129         _exception(SIGBUS, regs, BUS_ADRALN, regs->pc);
 130 }
 131
 132 /* This way of handling undefined instructions is stolen from ARM */
 133 static LIST_HEAD(undef_hook);
 134 static DEFINE_SPINLOCK(undef_lock);
 135
 136 void register_undef_hook(struct undef_hook *hook)
 137 {
 138         spin_lock_irq(&undef_lock);
 139         list_add(&hook->node, &undef_hook);
 140         spin_unlock_irq(&undef_lock);
 141 }
 142
 143 void unregister_undef_hook(struct undef_hook *hook)
 144 {
 145         spin_lock_irq(&undef_lock);
 146         list_del(&hook->node);
 147         spin_unlock_irq(&undef_lock);
 148 }
 149
 150 static int do_cop_absent(u32 insn)
 151 {
 152         int cop_nr;
 153         u32 cpucr;
 154
 155         if ((insn & 0xfdf00000) == 0xf1900000)
 156                 /* LDC0 */
 157                 cop_nr = 0;
 158         else
 159                 cop_nr = (insn >> 13) & 0x7;
 160
 161         /* Try enabling the coprocessor */
 162         cpucr = sysreg_read(CPUCR);
 163         cpucr |= (1 << (24 + cop_nr));
 164         sysreg_write(CPUCR, cpucr);
 165
 166         cpucr = sysreg_read(CPUCR);
 167         if (!(cpucr & (1 << (24 + cop_nr))))
 168                 return -ENODEV;
 169
 170         return 0;
 171 }
 172
 173 #ifdef CONFIG_BUG
 174 int is_valid_bugaddr(unsigned long pc)
 175 {
 176         unsigned short opcode;
 177
 178         if (pc < PAGE_OFFSET)
 179                 return 0;
 180         if (probe_kernel_address((u16 *)pc, opcode))
 181                 return 0;
 182
 183         return opcode == AVR32_BUG_OPCODE;
 184 }
 185 #endif
 186
 187 asmlinkage void do_illegal_opcode(unsigned long ecr, struct pt_regs *regs)
 188 {
 189         u32 insn;
 190         struct undef_hook *hook;
 191         void __user *pc;
 192         long code;
 193
 194 #ifdef CONFIG_BUG
 195         if (!user_mode(regs) && (ecr == ECR_ILLEGAL_OPCODE)) {
 196                 enum bug_trap_type type;
 197
 198                 type = report_bug(regs->pc, regs);
 199                 switch (type) {
 200                 case BUG_TRAP_TYPE_NONE:
 201                         break;
 202                 case BUG_TRAP_TYPE_WARN:
 203                         regs->pc += 2;
 204                         return;
 205                 case BUG_TRAP_TYPE_BUG:
 206                         die("Kernel BUG", regs, SIGKILL);
 207                 }
 208         }
 209 #endif
 210
 211         local_irq_enable();
 212
 213         if (user_mode(regs)) {
 214                 pc = (void __user *)instruction_pointer(regs);
 215                 if (get_user(insn, (u32 __user *)pc))
 216                         goto invalid_area;
 217
 218                 if (ecr == ECR_COPROC_ABSENT && !do_cop_absent(insn))
 219                         return;
 220
 221                 spin_lock_irq(&undef_lock);
 222                 list_for_each_entry(hook, &undef_hook, node) {
 223                         if ((insn & hook->insn_mask) == hook->insn_val) {
 224                                 if (hook->fn(regs, insn) == 0) {
 225                                         spin_unlock_irq(&undef_lock);
 226                                         return;
 227                                 }
 228                         }
 229                 }
 230                 spin_unlock_irq(&undef_lock);
 231         }
 232
 233         switch (ecr) {
 234         case ECR_PRIVILEGE_VIOLATION:
 235                 code = ILL_PRVOPC;
 236                 break;
 237         case ECR_COPROC_ABSENT:
 238                 code = ILL_COPROC;
 239                 break;
 240         default:
 241                 code = ILL_ILLOPC;
 242                 break;
 243         }
 244
 245         _exception(SIGILL, regs, code, regs->pc);
 246         return;
 247
 248 invalid_area:
 249         _exception(SIGSEGV, regs, SEGV_MAPERR, regs->pc);
 250 }
 251
 252 asmlinkage void do_fpe(unsigned long ecr, struct pt_regs *regs)
 253 {
 254         /* We have no FPU yet */
 255         _exception(SIGILL, regs, ILL_COPROC, regs->pc);
 256 }
 257
 258
 259 void __init trap_init(void)
 260 {
 261
 262 }