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 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, LOCKDEP_NOW_UNRELIABLE);
  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 asmlinkage void do_nmi(unsigned long ecr, struct pt_regs *regs)
 101 {
 102         int ret;
 103
 104         nmi_enter();
 105
 106         ret = notify_die(DIE_NMI, "NMI", regs, 0, ecr, SIGINT);
 107         switch (ret) {
 108         case NOTIFY_OK:
 109         case NOTIFY_STOP:
 110                 break;
 111         case NOTIFY_BAD:
 112                 die("Fatal Non-Maskable Interrupt", regs, SIGINT);
 113         default:
 114                 printk(KERN_ALERT "Got NMI, but nobody cared. Disabling...\n");
 115                 nmi_disable();
 116                 break;
 117         }
 118         nmi_exit();
 119 }
 120
 121 asmlinkage void do_critical_exception(unsigned long ecr, struct pt_regs *regs)
 122 {
 123         die("Critical exception", regs, SIGKILL);
 124 }
 125
 126 asmlinkage void do_address_exception(unsigned long ecr, struct pt_regs *regs)
 127 {
 128         _exception(SIGBUS, regs, BUS_ADRALN, regs->pc);
 129 }
 130
 131 /* This way of handling undefined instructions is stolen from ARM */
 132 static LIST_HEAD(undef_hook);
 133 static DEFINE_SPINLOCK(undef_lock);
 134
 135 void register_undef_hook(struct undef_hook *hook)
 136 {
 137         spin_lock_irq(&undef_lock);
 138         list_add(&hook->node, &undef_hook);
 139         spin_unlock_irq(&undef_lock);
 140 }
 141
 142 void unregister_undef_hook(struct undef_hook *hook)
 143 {
 144         spin_lock_irq(&undef_lock);
 145         list_del(&hook->node);
 146         spin_unlock_irq(&undef_lock);
 147 }
 148
 149 static int do_cop_absent(u32 insn)
 150 {
 151         int cop_nr;
 152         u32 cpucr;
 153
 154         if ((insn & 0xfdf00000) == 0xf1900000)
 155                 /* LDC0 */
 156                 cop_nr = 0;
 157         else
 158                 cop_nr = (insn >> 13) & 0x7;
 159
 160         /* Try enabling the coprocessor */
 161         cpucr = sysreg_read(CPUCR);
 162         cpucr |= (1 << (24 + cop_nr));
 163         sysreg_write(CPUCR, cpucr);
 164
 165         cpucr = sysreg_read(CPUCR);
 166         if (!(cpucr & (1 << (24 + cop_nr))))
 167                 return -ENODEV;
 168
 169         return 0;
 170 }
 171
 172 #ifdef CONFIG_BUG
 173 int is_valid_bugaddr(unsigned long pc)
 174 {
 175         unsigned short opcode;
 176
 177         if (pc < PAGE_OFFSET)
 178                 return 0;
 179         if (probe_kernel_address((u16 *)pc, opcode))
 180                 return 0;
 181
 182         return opcode == AVR32_BUG_OPCODE;
 183 }
 184 #endif
 185
 186 asmlinkage void do_illegal_opcode(unsigned long ecr, struct pt_regs *regs)
 187 {
 188         u32 insn;
 189         struct undef_hook *hook;
 190         void __user *pc;
 191         long code;
 192
 193 #ifdef CONFIG_BUG
 194         if (!user_mode(regs) && (ecr == ECR_ILLEGAL_OPCODE)) {
 195                 enum bug_trap_type type;
 196
 197                 type = report_bug(regs->pc, regs);
 198                 switch (type) {
 199                 case BUG_TRAP_TYPE_NONE:
 200                         break;
 201                 case BUG_TRAP_TYPE_WARN:
 202                         regs->pc += 2;
 203                         return;
 204                 case BUG_TRAP_TYPE_BUG:
 205                         die("Kernel BUG", regs, SIGKILL);
 206                 }
 207         }
 208 #endif
 209
 210         local_irq_enable();
 211
 212         if (user_mode(regs)) {
 213                 pc = (void __user *)instruction_pointer(regs);
 214                 if (get_user(insn, (u32 __user *)pc))
 215                         goto invalid_area;
 216
 217                 if (ecr == ECR_COPROC_ABSENT && !do_cop_absent(insn))
 218                         return;
 219
 220                 spin_lock_irq(&undef_lock);
 221                 list_for_each_entry(hook, &undef_hook, node) {
 222                         if ((insn & hook->insn_mask) == hook->insn_val) {
 223                                 if (hook->fn(regs, insn) == 0) {
 224                                         spin_unlock_irq(&undef_lock);
 225                                         return;
 226                                 }
 227                         }
 228                 }
 229                 spin_unlock_irq(&undef_lock);
 230         }
 231
 232         switch (ecr) {
 233         case ECR_PRIVILEGE_VIOLATION:
 234                 code = ILL_PRVOPC;
 235                 break;
 236         case ECR_COPROC_ABSENT:
 237                 code = ILL_COPROC;
 238                 break;
 239         default:
 240                 code = ILL_ILLOPC;
 241                 break;
 242         }
 243
 244         _exception(SIGILL, regs, code, regs->pc);
 245         return;
 246
 247 invalid_area:
 248         _exception(SIGSEGV, regs, SEGV_MAPERR, regs->pc);
 249 }
 250
 251 asmlinkage void do_fpe(unsigned long ecr, struct pt_regs *regs)
 252 {
 253         /* We have no FPU yet */
 254         _exception(SIGILL, regs, ILL_COPROC, regs->pc);
 255 }
 256
 257
 258 void __init trap_init(void)
 259 {
 260
 261 }