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/kdebug.h>
  13 #include <linux/module.h>
  14 #include <linux/notifier.h>
  15 #include <linux/sched.h>
  16 #include <linux/uaccess.h>
  17
  18 #include <asm/addrspace.h>
  19 #include <asm/mmu_context.h>
  20 #include <asm/ocd.h>
  21 #include <asm/sysreg.h>
  22 #include <asm/traps.h>
  23
  24 static DEFINE_SPINLOCK(die_lock);
  25
  26 void NORET_TYPE die(const char *str, struct pt_regs *regs, long err)
  27 {
  28         static int die_counter;
  29
  30         console_verbose();
  31         spin_lock_irq(&die_lock);
  32         bust_spinlocks(1);
  33
  34         printk(KERN_ALERT "Oops: %s, sig: %ld [#%d]\n" KERN_EMERG,
  35                str, err, ++die_counter);
  36 #ifdef CONFIG_PREEMPT
  37         printk("PREEMPT ");
  38 #endif
  39 #ifdef CONFIG_FRAME_POINTER
  40         printk("FRAME_POINTER ");
  41 #endif
  42         if (current_cpu_data.features & AVR32_FEATURE_OCD) {
  43                 unsigned long did = ocd_read(DID);
  44                 printk("chip: 0x%03lx:0x%04lx rev %lu\n",
  45                        (did >> 1) & 0x7ff,
  46                        (did >> 12) & 0x7fff,
  47                        (did >> 28) & 0xf);
  48         } else {
  49                 printk("cpu: arch %u r%u / core %u r%u\n",
  50                        current_cpu_data.arch_type,
  51                        current_cpu_data.arch_revision,
  52                        current_cpu_data.cpu_type,
  53                        current_cpu_data.cpu_revision);
  54         }
  55
  56         print_modules();
  57         show_regs_log_lvl(regs, KERN_EMERG);
  58         show_stack_log_lvl(current, regs->sp, regs, KERN_EMERG);
  59         bust_spinlocks(0);
  60         add_taint(TAINT_DIE);
  61         spin_unlock_irq(&die_lock);
  62
  63         if (in_interrupt())
  64                 panic("Fatal exception in interrupt");
  65
  66         if (panic_on_oops)
  67                 panic("Fatal exception");
  68
  69         do_exit(err);
  70 }
  71
  72 void _exception(long signr, struct pt_regs *regs, int code,
  73                 unsigned long addr)
  74 {
  75         siginfo_t info;
  76
  77         if (!user_mode(regs))
  78                 die("Unhandled exception in kernel mode", regs, signr);
  79
  80         memset(&info, 0, sizeof(info));
  81         info.si_signo = signr;
  82         info.si_code = code;
  83         info.si_addr = (void __user *)addr;
  84         force_sig_info(signr, &info, current);
  85
  86         /*
  87          * Init gets no signals that it doesn't have a handler for.
  88          * That's all very well, but if it has caused a synchronous
  89          * exception and we ignore the resulting signal, it will just
  90          * generate the same exception over and over again and we get
  91          * nowhere.  Better to kill it and let the kernel panic.
  92          */
  93         if (is_global_init(current)) {
  94                 __sighandler_t handler;
  95
  96                 spin_lock_irq(&current->sighand->siglock);
  97                 handler = current->sighand->action[signr-1].sa.sa_handler;
  98                 spin_unlock_irq(&current->sighand->siglock);
  99                 if (handler == SIG_DFL) {
 100                         /* init has generated a synchronous exception
 101                            and it doesn't have a handler for the signal */
 102                         printk(KERN_CRIT "init has generated signal %ld "
 103                                "but has no handler for it\n", signr);
 104                         do_exit(signr);
 105                 }
 106         }
 107 }
 108
 109 asmlinkage void do_nmi(unsigned long ecr, struct pt_regs *regs)
 110 {
 111         int ret;
 112
 113         nmi_enter();
 114
 115         ret = notify_die(DIE_NMI, "NMI", regs, 0, ecr, SIGINT);
 116         switch (ret) {
 117         case NOTIFY_OK:
 118         case NOTIFY_STOP:
 119                 return;
 120         case NOTIFY_BAD:
 121                 die("Fatal Non-Maskable Interrupt", regs, SIGINT);
 122         default:
 123                 break;
 124         }
 125
 126         printk(KERN_ALERT "Got NMI, but nobody cared. Disabling...\n");
 127         nmi_disable();
 128 }
 129
 130 asmlinkage void do_critical_exception(unsigned long ecr, struct pt_regs *regs)
 131 {
 132         die("Critical exception", regs, SIGKILL);
 133 }
 134
 135 asmlinkage void do_address_exception(unsigned long ecr, struct pt_regs *regs)
 136 {
 137         _exception(SIGBUS, regs, BUS_ADRALN, regs->pc);
 138 }
 139
 140 /* This way of handling undefined instructions is stolen from ARM */
 141 static LIST_HEAD(undef_hook);
 142 static DEFINE_SPINLOCK(undef_lock);
 143
 144 void register_undef_hook(struct undef_hook *hook)
 145 {
 146         spin_lock_irq(&undef_lock);
 147         list_add(&hook->node, &undef_hook);
 148         spin_unlock_irq(&undef_lock);
 149 }
 150
 151 void unregister_undef_hook(struct undef_hook *hook)
 152 {
 153         spin_lock_irq(&undef_lock);
 154         list_del(&hook->node);
 155         spin_unlock_irq(&undef_lock);
 156 }
 157
 158 static int do_cop_absent(u32 insn)
 159 {
 160         int cop_nr;
 161         u32 cpucr;
 162
 163         if ((insn & 0xfdf00000) == 0xf1900000)
 164                 /* LDC0 */
 165                 cop_nr = 0;
 166         else
 167                 cop_nr = (insn >> 13) & 0x7;
 168
 169         /* Try enabling the coprocessor */
 170         cpucr = sysreg_read(CPUCR);
 171         cpucr |= (1 << (24 + cop_nr));
 172         sysreg_write(CPUCR, cpucr);
 173
 174         cpucr = sysreg_read(CPUCR);
 175         if (!(cpucr & (1 << (24 + cop_nr))))
 176                 return -ENODEV;
 177
 178         return 0;
 179 }
 180
 181 #ifdef CONFIG_BUG
 182 int is_valid_bugaddr(unsigned long pc)
 183 {
 184         unsigned short opcode;
 185
 186         if (pc < PAGE_OFFSET)
 187                 return 0;
 188         if (probe_kernel_address((u16 *)pc, opcode))
 189                 return 0;
 190
 191         return opcode == AVR32_BUG_OPCODE;
 192 }
 193 #endif
 194
 195 asmlinkage void do_illegal_opcode(unsigned long ecr, struct pt_regs *regs)
 196 {
 197         u32 insn;
 198         struct undef_hook *hook;
 199         void __user *pc;
 200         long code;
 201
 202 #ifdef CONFIG_BUG
 203         if (!user_mode(regs) && (ecr == ECR_ILLEGAL_OPCODE)) {
 204                 enum bug_trap_type type;
 205
 206                 type = report_bug(regs->pc, regs);
 207                 switch (type) {
 208                 case BUG_TRAP_TYPE_NONE:
 209                         break;
 210                 case BUG_TRAP_TYPE_WARN:
 211                         regs->pc += 2;
 212                         return;
 213                 case BUG_TRAP_TYPE_BUG:
 214                         die("Kernel BUG", regs, SIGKILL);
 215                 }
 216         }
 217 #endif
 218
 219         local_irq_enable();
 220
 221         if (user_mode(regs)) {
 222                 pc = (void __user *)instruction_pointer(regs);
 223                 if (get_user(insn, (u32 __user *)pc))
 224                         goto invalid_area;
 225
 226                 if (ecr == ECR_COPROC_ABSENT && !do_cop_absent(insn))
 227                         return;
 228
 229                 spin_lock_irq(&undef_lock);
 230                 list_for_each_entry(hook, &undef_hook, node) {
 231                         if ((insn & hook->insn_mask) == hook->insn_val) {
 232                                 if (hook->fn(regs, insn) == 0) {
 233                                         spin_unlock_irq(&undef_lock);
 234                                         return;
 235                                 }
 236                         }
 237                 }
 238                 spin_unlock_irq(&undef_lock);
 239         }
 240
 241         switch (ecr) {
 242         case ECR_PRIVILEGE_VIOLATION:
 243                 code = ILL_PRVOPC;
 244                 break;
 245         case ECR_COPROC_ABSENT:
 246                 code = ILL_COPROC;
 247                 break;
 248         default:
 249                 code = ILL_ILLOPC;
 250                 break;
 251         }
 252
 253         _exception(SIGILL, regs, code, regs->pc);
 254         return;
 255
 256 invalid_area:
 257         _exception(SIGSEGV, regs, SEGV_MAPERR, regs->pc);
 258 }
 259
 260 asmlinkage void do_fpe(unsigned long ecr, struct pt_regs *regs)
 261 {
 262         /* We have no FPU yet */
 263         _exception(SIGILL, regs, ILL_COPROC, regs->pc);
 264 }
 265
 266
 267 void __init trap_init(void)
 268 {
 269
 270 }