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 <linux/sched/debug.h>
  14
  15 #include <asm/trace.h>
  16
  17 /*
  18  * Checks to see if the address pointed to is either a
  19  * 16-bit CALL instruction, or a 32-bit CALL instruction
  20  */
  21 static bool is_bfin_call(unsigned short *addr)
  22 {
  23         unsigned int opcode;
  24
  25         if (!get_instruction(&opcode, addr))
  26                 return false;
  27
  28         if ((opcode >= 0x0060 && opcode <= 0x0067) ||
  29             (opcode >= 0x0070 && opcode <= 0x0077) ||
  30             (opcode >= 0xE3000000 && opcode <= 0xE3FFFFFF))
  31                 return true;
  32
  33         return false;
  34
  35 }
  36
  37 void show_stack(struct task_struct *task, unsigned long *stack)
  38 {
  39 #ifdef CONFIG_PRINTK
  40         unsigned int *addr, *endstack, *fp = 0, *frame;
  41         unsigned short *ins_addr;
  42         char buf[150];
  43         unsigned int i, j, ret_addr, frame_no = 0;
  44
  45         /*
  46          * If we have been passed a specific stack, use that one otherwise
  47          *    if we have been passed a task structure, use that, otherwise
  48          *    use the stack of where the variable "stack" exists
  49          */
  50
  51         if (stack == NULL) {
  52                 if (task) {
  53                         /* We know this is a kernel stack, so this is the start/end */
  54                         stack = (unsigned long *)task->thread.ksp;
  55                         endstack = (unsigned int *)(((unsigned int)(stack) & ~(THREAD_SIZE - 1)) + THREAD_SIZE);
  56                 } else {
  57                         /* print out the existing stack info */
  58                         stack = (unsigned long *)&stack;
  59                         endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
  60                 }
  61         } else
  62                 endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
  63
  64         printk(KERN_NOTICE "Stack info:\n");
  65         decode_address(buf, (unsigned int)stack);
  66         printk(KERN_NOTICE " SP: [0x%p] %s\n", stack, buf);
  67
  68         if (!access_ok(VERIFY_READ, stack, (unsigned int)endstack - (unsigned int)stack)) {
  69                 printk(KERN_NOTICE "Invalid stack pointer\n");
  70                 return;
  71         }
  72
  73         /* First thing is to look for a frame pointer */
  74         for (addr = (unsigned int *)((unsigned int)stack & ~0xF); addr < endstack; addr++) {
  75                 if (*addr & 0x1)
  76                         continue;
  77                 ins_addr = (unsigned short *)*addr;
  78                 ins_addr--;
  79                 if (is_bfin_call(ins_addr))
  80                         fp = addr - 1;
  81
  82                 if (fp) {
  83                         /* Let's check to see if it is a frame pointer */
  84                         while (fp >= (addr - 1) && fp < endstack
  85                                && fp && ((unsigned int) fp & 0x3) == 0)
  86                                 fp = (unsigned int *)*fp;
  87                         if (fp == 0 || fp == endstack) {
  88                                 fp = addr - 1;
  89                                 break;
  90                         }
  91                         fp = 0;
  92                 }
  93         }
  94         if (fp) {
  95                 frame = fp;
  96                 printk(KERN_NOTICE " FP: (0x%p)\n", fp);
  97         } else
  98                 frame = 0;
  99
 100         /*
 101          * Now that we think we know where things are, we
 102          * walk the stack again, this time printing things out
 103          * incase there is no frame pointer, we still look for
 104          * valid return addresses
 105          */
 106
 107         /* First time print out data, next time, print out symbols */
 108         for (j = 0; j <= 1; j++) {
 109                 if (j)
 110                         printk(KERN_NOTICE "Return addresses in stack:\n");
 111                 else
 112                         printk(KERN_NOTICE " Memory from 0x%08lx to %p", ((long unsigned int)stack & ~0xF), endstack);
 113
 114                 fp = frame;
 115                 frame_no = 0;
 116
 117                 for (addr = (unsigned int *)((unsigned int)stack & ~0xF), i = 0;
 118                      addr < endstack; addr++, i++) {
 119
 120                         ret_addr = 0;
 121                         if (!j && i % 8 == 0)
 122                                 printk(KERN_NOTICE "%p:", addr);
 123
 124                         /* if it is an odd address, or zero, just skip it */
 125                         if (*addr & 0x1 || !*addr)
 126                                 goto print;
 127
 128                         ins_addr = (unsigned short *)*addr;
 129
 130                         /* Go back one instruction, and see if it is a CALL */
 131                         ins_addr--;
 132                         ret_addr = is_bfin_call(ins_addr);
 133  print:
 134                         if (!j && stack == (unsigned long *)addr)
 135                                 printk("[%08x]", *addr);
 136                         else if (ret_addr)
 137                                 if (j) {
 138                                         decode_address(buf, (unsigned int)*addr);
 139                                         if (frame == addr) {
 140                                                 printk(KERN_NOTICE "   frame %2i : %s\n", frame_no, buf);
 141                                                 continue;
 142                                         }
 143                                         printk(KERN_NOTICE "    address : %s\n", buf);
 144                                 } else
 145                                         printk("<%08x>", *addr);
 146                         else if (fp == addr) {
 147                                 if (j)
 148                                         frame = addr+1;
 149                                 else
 150                                         printk("(%08x)", *addr);
 151
 152                                 fp = (unsigned int *)*addr;
 153                                 frame_no++;
 154
 155                         } else if (!j)
 156                                 printk(" %08x ", *addr);
 157                 }
 158                 if (!j)
 159                         printk("\n");
 160         }
 161 #endif
 162 }
 163 EXPORT_SYMBOL(show_stack);
 164
 165 void dump_stack(void)
 166 {
 167         unsigned long stack;
 168 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
 169         int tflags;
 170 #endif
 171         trace_buffer_save(tflags);
 172         dump_bfin_trace_buffer();
 173         dump_stack_print_info(KERN_DEFAULT);
 174         show_stack(current, &stack);
 175         trace_buffer_restore(tflags);
 176 }
 177 EXPORT_SYMBOL(dump_stack);