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/* Provide basic stack dumping functions
*
* Copyright 2004-2009 Analog Devices Inc.
*
* Licensed under the GPL-2 or later
*/
#include <linux/kernel.h>
#include <linux/thread_info.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <asm/trace.h>
/*
* Checks to see if the address pointed to is either a
* 16-bit CALL instruction, or a 32-bit CALL instruction
*/
static bool is_bfin_call(unsigned short *addr)
{
unsigned short opcode = 0, *ins_addr;
ins_addr = (unsigned short *)addr;
if (!get_instruction(&opcode, ins_addr))
return false;
if ((opcode >= 0x0060 && opcode <= 0x0067) ||
(opcode >= 0x0070 && opcode <= 0x0077))
return true;
ins_addr--;
if (!get_instruction(&opcode, ins_addr))
return false;
if (opcode >= 0xE300 && opcode <= 0xE3FF)
return true;
return false;
}
void show_stack(struct task_struct *task, unsigned long *stack)
{
#ifdef CONFIG_PRINTK
unsigned int *addr, *endstack, *fp = 0, *frame;
unsigned short *ins_addr;
char buf[150];
unsigned int i, j, ret_addr, frame_no = 0;
/*
* If we have been passed a specific stack, use that one otherwise
* if we have been passed a task structure, use that, otherwise
* use the stack of where the variable "stack" exists
*/
if (stack == NULL) {
if (task) {
/* We know this is a kernel stack, so this is the start/end */
stack = (unsigned long *)task->thread.ksp;
endstack = (unsigned int *)(((unsigned int)(stack) & ~(THREAD_SIZE - 1)) + THREAD_SIZE);
} else {
/* print out the existing stack info */
stack = (unsigned long *)&stack;
endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
}
} else
endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
printk(KERN_NOTICE "Stack info:\n");
decode_address(buf, (unsigned int)stack);
printk(KERN_NOTICE " SP: [0x%p] %s\n", stack, buf);
if (!access_ok(VERIFY_READ, stack, (unsigned int)endstack - (unsigned int)stack)) {
printk(KERN_NOTICE "Invalid stack pointer\n");
return;
}
/* First thing is to look for a frame pointer */
for (addr = (unsigned int *)((unsigned int)stack & ~0xF); addr < endstack; addr++) {
if (*addr & 0x1)
continue;
ins_addr = (unsigned short *)*addr;
ins_addr--;
if (is_bfin_call(ins_addr))
fp = addr - 1;
if (fp) {
/* Let's check to see if it is a frame pointer */
while (fp >= (addr - 1) && fp < endstack
&& fp && ((unsigned int) fp & 0x3) == 0)
fp = (unsigned int *)*fp;
if (fp == 0 || fp == endstack) {
fp = addr - 1;
break;
}
fp = 0;
}
}
if (fp) {
frame = fp;
printk(KERN_NOTICE " FP: (0x%p)\n", fp);
} else
frame = 0;
/*
* Now that we think we know where things are, we
* walk the stack again, this time printing things out
* incase there is no frame pointer, we still look for
* valid return addresses
*/
/* First time print out data, next time, print out symbols */
for (j = 0; j <= 1; j++) {
if (j)
printk(KERN_NOTICE "Return addresses in stack:\n");
else
printk(KERN_NOTICE " Memory from 0x%08lx to %p", ((long unsigned int)stack & ~0xF), endstack);
fp = frame;
frame_no = 0;
for (addr = (unsigned int *)((unsigned int)stack & ~0xF), i = 0;
addr < endstack; addr++, i++) {
ret_addr = 0;
if (!j && i % 8 == 0)
printk(KERN_NOTICE "%p:", addr);
/* if it is an odd address, or zero, just skip it */
if (*addr & 0x1 || !*addr)
goto print;
ins_addr = (unsigned short *)*addr;
/* Go back one instruction, and see if it is a CALL */
ins_addr--;
ret_addr = is_bfin_call(ins_addr);
print:
if (!j && stack == (unsigned long *)addr)
printk("[%08x]", *addr);
else if (ret_addr)
if (j) {
decode_address(buf, (unsigned int)*addr);
if (frame == addr) {
printk(KERN_NOTICE " frame %2i : %s\n", frame_no, buf);
continue;
}
printk(KERN_NOTICE " address : %s\n", buf);
} else
printk("<%08x>", *addr);
else if (fp == addr) {
if (j)
frame = addr+1;
else
printk("(%08x)", *addr);
fp = (unsigned int *)*addr;
frame_no++;
} else if (!j)
printk(" %08x ", *addr);
}
if (!j)
printk("\n");
}
#endif
}
EXPORT_SYMBOL(show_stack);
void dump_stack(void)
{
unsigned long stack;
#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
int tflags;
#endif
trace_buffer_save(tflags);
dump_bfin_trace_buffer();
show_stack(current, &stack);
trace_buffer_restore(tflags);
}
EXPORT_SYMBOL(dump_stack);
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