arch/blackfin/kernel/dumpstack.c

   1 /* Provide basic stack dumping functions
   2  *
   3  * Copyright 2004-2009 Analog Devices Inc.
   4  *
   5  * Licensed under the GPL-2 or later
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/thread_info.h>
  10 #include <linux/mm.h>
  11 #include <linux/uaccess.h>
  12 #include <linux/module.h>
  13 #include <asm/trace.h>
  14
  15 /*
  16  * Checks to see if the address pointed to is either a
  17  * 16-bit CALL instruction, or a 32-bit CALL instruction
  18  */
  19 static bool is_bfin_call(unsigned short *addr)
  20 {
  21         unsigned int opcode;
  22
  23         if (!get_instruction(&opcode, addr))
  24                 return false;
  25
  26         if ((opcode >= 0x0060 && opcode <= 0x0067) ||
  27             (opcode >= 0x0070 && opcode <= 0x0077) ||
  28             (opcode >= 0xE3000000 && opcode <= 0xE3FFFFFF))
  29                 return true;
  30
  31         return false;
  32
  33 }
  34
  35 void show_stack(struct task_struct *task, unsigned long *stack)
  36 {
  37 #ifdef CONFIG_PRINTK
  38         unsigned int *addr, *endstack, *fp = 0, *frame;
  39         unsigned short *ins_addr;
  40         char buf[150];
  41         unsigned int i, j, ret_addr, frame_no = 0;
  42
  43         /*
  44          * If we have been passed a specific stack, use that one otherwise
  45          *    if we have been passed a task structure, use that, otherwise
  46          *    use the stack of where the variable "stack" exists
  47          */
  48
  49         if (stack == NULL) {
  50                 if (task) {
  51                         /* We know this is a kernel stack, so this is the start/end */
  52                         stack = (unsigned long *)task->thread.ksp;
  53                         endstack = (unsigned int *)(((unsigned int)(stack) & ~(THREAD_SIZE - 1)) + THREAD_SIZE);
  54                 } else {
  55                         /* print out the existing stack info */
  56                         stack = (unsigned long *)&stack;
  57                         endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
  58                 }
  59         } else
  60                 endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
  61
  62         printk(KERN_NOTICE "Stack info:\n");
  63         decode_address(buf, (unsigned int)stack);
  64         printk(KERN_NOTICE " SP: [0x%p] %s\n", stack, buf);
  65
  66         if (!access_ok(VERIFY_READ, stack, (unsigned int)endstack - (unsigned int)stack)) {
  67                 printk(KERN_NOTICE "Invalid stack pointer\n");
  68                 return;
  69         }
  70
  71         /* First thing is to look for a frame pointer */
  72         for (addr = (unsigned int *)((unsigned int)stack & ~0xF); addr < endstack; addr++) {
  73                 if (*addr & 0x1)
  74                         continue;
  75                 ins_addr = (unsigned short *)*addr;
  76                 ins_addr--;
  77                 if (is_bfin_call(ins_addr))
  78                         fp = addr - 1;
  79
  80                 if (fp) {
  81                         /* Let's check to see if it is a frame pointer */
  82                         while (fp >= (addr - 1) && fp < endstack
  83                                && fp && ((unsigned int) fp & 0x3) == 0)
  84                                 fp = (unsigned int *)*fp;
  85                         if (fp == 0 || fp == endstack) {
  86                                 fp = addr - 1;
  87                                 break;
  88                         }
  89                         fp = 0;
  90                 }
  91         }
  92         if (fp) {
  93                 frame = fp;
  94                 printk(KERN_NOTICE " FP: (0x%p)\n", fp);
  95         } else
  96                 frame = 0;
  97
  98         /*
  99          * Now that we think we know where things are, we
 100          * walk the stack again, this time printing things out
 101          * incase there is no frame pointer, we still look for
 102          * valid return addresses
 103          */
 104
 105         /* First time print out data, next time, print out symbols */
 106         for (j = 0; j <= 1; j++) {
 107                 if (j)
 108                         printk(KERN_NOTICE "Return addresses in stack:\n");
 109                 else
 110                         printk(KERN_NOTICE " Memory from 0x%08lx to %p", ((long unsigned int)stack & ~0xF), endstack);
 111
 112                 fp = frame;
 113                 frame_no = 0;
 114
 115                 for (addr = (unsigned int *)((unsigned int)stack & ~0xF), i = 0;
 116                      addr < endstack; addr++, i++) {
 117
 118                         ret_addr = 0;
 119                         if (!j && i % 8 == 0)
 120                                 printk(KERN_NOTICE "%p:", addr);
 121
 122                         /* if it is an odd address, or zero, just skip it */
 123                         if (*addr & 0x1 || !*addr)
 124                                 goto print;
 125
 126                         ins_addr = (unsigned short *)*addr;
 127
 128                         /* Go back one instruction, and see if it is a CALL */
 129                         ins_addr--;
 130                         ret_addr = is_bfin_call(ins_addr);
 131  print:
 132                         if (!j && stack == (unsigned long *)addr)
 133                                 printk("[%08x]", *addr);
 134                         else if (ret_addr)
 135                                 if (j) {
 136                                         decode_address(buf, (unsigned int)*addr);
 137                                         if (frame == addr) {
 138                                                 printk(KERN_NOTICE "   frame %2i : %s\n", frame_no, buf);
 139                                                 continue;
 140                                         }
 141                                         printk(KERN_NOTICE "    address : %s\n", buf);
 142                                 } else
 143                                         printk("<%08x>", *addr);
 144                         else if (fp == addr) {
 145                                 if (j)
 146                                         frame = addr+1;
 147                                 else
 148                                         printk("(%08x)", *addr);
 149
 150                                 fp = (unsigned int *)*addr;
 151                                 frame_no++;
 152
 153                         } else if (!j)
 154                                 printk(" %08x ", *addr);
 155                 }
 156                 if (!j)
 157                         printk("\n");
 158         }
 159 #endif
 160 }
 161 EXPORT_SYMBOL(show_stack);
 162
 163 void dump_stack(void)
 164 {
 165         unsigned long stack;
 166 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
 167         int tflags;
 168 #endif
 169         trace_buffer_save(tflags);
 170         dump_bfin_trace_buffer();
 171         show_stack(current, &stack);
 172         trace_buffer_restore(tflags);
 173 }
 174 EXPORT_SYMBOL(dump_stack);