linux/arch/microblaze/kernel/traps.c
Steven J. Magnani ce3266c047 microblaze: Add stack unwinder
Implement intelligent backtracing by searching for stack frame creation,
and emitting only return addresses. Use print_hex_dump() to display the
entire binary kernel stack.

Limitation: MMU kernels are not currently able to trace beyond a system trap
(interrupt, syscall, etc.). It is the intent of this patch to provide
infrastructure that can be extended to add this capability later.

Changes from V1:
* Removed checks in find_frame_creation() that prevented location of the frame
  creation instruction in heavily optimized code
* Various formatting/commenting/file location tweaks per review comments
* Dropped Kconfig option to enable STACKTRACE as something logically separate

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
2010-08-04 10:22:35 +02:00

87 lines
2.0 KiB
C

/*
* Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
* Copyright (C) 2007-2009 PetaLogix
* Copyright (C) 2006 Atmark Techno, Inc.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/kernel.h>
#include <linux/kallsyms.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/debug_locks.h>
#include <asm/exceptions.h>
#include <asm/system.h>
#include <asm/unwind.h>
void trap_init(void)
{
__enable_hw_exceptions();
}
static unsigned long kstack_depth_to_print; /* 0 == entire stack */
static int __init kstack_setup(char *s)
{
return !strict_strtoul(s, 0, &kstack_depth_to_print);
}
__setup("kstack=", kstack_setup);
void show_stack(struct task_struct *task, unsigned long *sp)
{
unsigned long words_to_show;
u32 fp = (u32) sp;
if (fp == 0) {
if (task) {
fp = ((struct thread_info *)
(task->stack))->cpu_context.r1;
} else {
/* Pick up caller of dump_stack() */
fp = (u32)&sp - 8;
}
}
words_to_show = (THREAD_SIZE - (fp & (THREAD_SIZE - 1))) >> 2;
if (kstack_depth_to_print && (words_to_show > kstack_depth_to_print))
words_to_show = kstack_depth_to_print;
pr_info("Kernel Stack:\n");
/*
* Make the first line an 'odd' size if necessary to get
* remaining lines to start at an address multiple of 0x10
*/
if (fp & 0xF) {
unsigned long line1_words = (0x10 - (fp & 0xF)) >> 2;
if (line1_words < words_to_show) {
print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 32,
4, (void *)fp, line1_words << 2, 0);
fp += line1_words << 2;
words_to_show -= line1_words;
}
}
print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 32, 4, (void *)fp,
words_to_show << 2, 0);
printk(KERN_INFO "\n\n");
pr_info("Call Trace:\n");
microblaze_unwind(task, NULL);
pr_info("\n");
if (!task)
task = current;
debug_show_held_locks(task);
}
void dump_stack(void)
{
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);