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