arch/cris/kernel/traps.c

   1 /*
   2  *  linux/arch/cris/traps.c
   3  *
   4  *  Here we handle the break vectors not used by the system call
   5  *  mechanism, as well as some general stack/register dumping
   6  *  things.
   7  *
   8  *  Copyright (C) 2000-2007 Axis Communications AB
   9  *
  10  *  Authors:   Bjorn Wesen
  11  *             Hans-Peter Nilsson
  12  *
  13  */
  14
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17
  18 #include <asm/pgtable.h>
  19 #include <asm/uaccess.h>
  20
  21 extern void arch_enable_nmi(void);
  22 extern void stop_watchdog(void);
  23 extern void reset_watchdog(void);
  24 extern void show_registers(struct pt_regs *regs);
  25
  26 #ifdef CONFIG_DEBUG_BUGVERBOSE
  27 extern void handle_BUG(struct pt_regs *regs);
  28 #else
  29 #define handle_BUG(regs)
  30 #endif
  31
  32 static int kstack_depth_to_print = 24;
  33
  34 void (*nmi_handler)(struct pt_regs *);
  35
  36 void
  37 show_trace(unsigned long *stack)
  38 {
  39         unsigned long addr, module_start, module_end;
  40         extern char _stext, _etext;
  41         int i;
  42
  43         printk("\nCall Trace: ");
  44
  45         i = 1;
  46         module_start = VMALLOC_START;
  47         module_end = VMALLOC_END;
  48
  49         while (((long)stack & (THREAD_SIZE-1)) != 0) {
  50                 if (__get_user(addr, stack)) {
  51                         /* This message matches "failing address" marked
  52                            s390 in ksymoops, so lines containing it will
  53                            not be filtered out by ksymoops.  */
  54                         printk("Failing address 0x%lx\n", (unsigned long)stack);
  55                         break;
  56                 }
  57                 stack++;
  58
  59                 /*
  60                  * If the address is either in the text segment of the
  61                  * kernel, or in the region which contains vmalloc'ed
  62                  * memory, it *may* be the address of a calling
  63                  * routine; if so, print it so that someone tracing
  64                  * down the cause of the crash will be able to figure
  65                  * out the call path that was taken.
  66                  */
  67                 if (((addr >= (unsigned long)&_stext) &&
  68                      (addr <= (unsigned long)&_etext)) ||
  69                     ((addr >= module_start) && (addr <= module_end))) {
  70                         if (i && ((i % 8) == 0))
  71                                 printk("\n       ");
  72                         printk("[<%08lx>] ", addr);
  73                         i++;
  74                 }
  75         }
  76 }
  77
  78 /*
  79  * These constants are for searching for possible module text
  80  * segments. MODULE_RANGE is a guess of how much space is likely
  81  * to be vmalloced.
  82  */
  83
  84 #define MODULE_RANGE (8*1024*1024)
  85
  86 /*
  87  * The output (format, strings and order) is adjusted to be usable with
  88  * ksymoops-2.4.1 with some necessary CRIS-specific patches.  Please don't
  89  * change it unless you're serious about adjusting ksymoops and syncing
  90  * with the ksymoops maintainer.
  91  */
  92
  93 void
  94 show_stack(struct task_struct *task, unsigned long *sp)
  95 {
  96         unsigned long *stack, addr;
  97         int i;
  98
  99         /*
 100          * debugging aid: "show_stack(NULL);" prints a
 101          * back trace.
 102          */
 103
 104         if (sp == NULL) {
 105                 if (task)
 106                         sp = (unsigned long*)task->thread.ksp;
 107                 else
 108                         sp = (unsigned long*)rdsp();
 109         }
 110
 111         stack = sp;
 112
 113         printk("\nStack from %08lx:\n       ", (unsigned long)stack);
 114         for (i = 0; i < kstack_depth_to_print; i++) {
 115                 if (((long)stack & (THREAD_SIZE-1)) == 0)
 116                         break;
 117                 if (i && ((i % 8) == 0))
 118                         printk("\n       ");
 119                 if (__get_user(addr, stack)) {
 120                         /* This message matches "failing address" marked
 121                            s390 in ksymoops, so lines containing it will
 122                            not be filtered out by ksymoops.  */
 123                         printk("Failing address 0x%lx\n", (unsigned long)stack);
 124                         break;
 125                 }
 126                 stack++;
 127                 printk("%08lx ", addr);
 128         }
 129         show_trace(sp);
 130 }
 131
 132 #if 0
 133 /* displays a short stack trace */
 134
 135 int
 136 show_stack(void)
 137 {
 138         unsigned long *sp = (unsigned long *)rdusp();
 139         int i;
 140
 141         printk("Stack dump [0x%08lx]:\n", (unsigned long)sp);
 142         for (i = 0; i < 16; i++)
 143                 printk("sp + %d: 0x%08lx\n", i*4, sp[i]);
 144         return 0;
 145 }
 146 #endif
 147
 148 void
 149 dump_stack(void)
 150 {
 151         show_stack(NULL, NULL);
 152 }
 153 EXPORT_SYMBOL(dump_stack);
 154
 155 void
 156 set_nmi_handler(void (*handler)(struct pt_regs *))
 157 {
 158         nmi_handler = handler;
 159         arch_enable_nmi();
 160 }
 161
 162 #ifdef CONFIG_DEBUG_NMI_OOPS
 163 void
 164 oops_nmi_handler(struct pt_regs *regs)
 165 {
 166         stop_watchdog();
 167         oops_in_progress = 1;
 168         printk("NMI!\n");
 169         show_registers(regs);
 170         oops_in_progress = 0;
 171 }
 172
 173 static int __init
 174 oops_nmi_register(void)
 175 {
 176         set_nmi_handler(oops_nmi_handler);
 177         return 0;
 178 }
 179
 180 __initcall(oops_nmi_register);
 181
 182 #endif
 183
 184 /*
 185  * This gets called from entry.S when the watchdog has bitten. Show something
 186  * similar to an Oops dump, and if the kernel is configured to be a nice
 187  * doggy, then halt instead of reboot.
 188  */
 189 void
 190 watchdog_bite_hook(struct pt_regs *regs)
 191 {
 192 #ifdef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
 193         local_irq_disable();
 194         stop_watchdog();
 195         show_registers(regs);
 196
 197         while (1)
 198                 ; /* Do nothing. */
 199 #else
 200         show_registers(regs);
 201 #endif
 202 }
 203
 204 /* This is normally the Oops function. */
 205 void
 206 die_if_kernel(const char *str, struct pt_regs *regs, long err)
 207 {
 208         if (user_mode(regs))
 209                 return;
 210
 211 #ifdef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
 212         /*
 213          * This printout might take too long and could trigger
 214          * the watchdog normally. If NICE_DOGGY is set, simply
 215          * stop the watchdog during the printout.
 216          */
 217         stop_watchdog();
 218 #endif
 219
 220         handle_BUG(regs);
 221
 222         printk("%s: %04lx\n", str, err & 0xffff);
 223
 224         show_registers(regs);
 225
 226         oops_in_progress = 0;
 227
 228 #ifdef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
 229         reset_watchdog();
 230 #endif
 231         do_exit(SIGSEGV);
 232 }
 233
 234 void __init
 235 trap_init(void)
 236 {
 237         /* Nothing needs to be done */
 238 }