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/*
* arch/mips/kernel/stacktrace.c
*
* Stack trace management functions
*
* Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
*/
#include <linux/sched.h>
#include <linux/stacktrace.h>
#include <asm/stacktrace.h>
/*
* Save stack-backtrace addresses into a stack_trace buffer:
*/
static void save_raw_context_stack(struct stack_trace *trace,
unsigned long reg29)
{
unsigned long *sp = (unsigned long *)reg29;
unsigned long addr;
while (!kstack_end(sp)) {
addr = *sp++;
if (__kernel_text_address(addr)) {
if (trace->skip > 0)
trace->skip--;
else
trace->entries[trace->nr_entries++] = addr;
if (trace->nr_entries >= trace->max_entries)
break;
}
}
}
static struct pt_regs * save_context_stack(struct stack_trace *trace,
struct task_struct *task, struct pt_regs *regs)
{
unsigned long sp = regs->regs[29];
#ifdef CONFIG_KALLSYMS
unsigned long ra = regs->regs[31];
unsigned long pc = regs->cp0_epc;
unsigned long stack_page =
(unsigned long)task_stack_page(task);
extern void ret_from_irq(void);
extern void ret_from_exception(void);
if (raw_show_trace || !__kernel_text_address(pc)) {
if (stack_page && sp >= stack_page &&
sp <= stack_page + THREAD_SIZE - 32)
save_raw_context_stack(trace, sp);
return NULL;
}
do {
if (trace->skip > 0)
trace->skip--;
else
trace->entries[trace->nr_entries++] = pc;
if (trace->nr_entries >= trace->max_entries)
break;
/*
* If we reached the bottom of interrupt context,
* return saved pt_regs.
*/
if (pc == (unsigned long)ret_from_irq ||
pc == (unsigned long)ret_from_exception) {
if (stack_page && sp >= stack_page &&
sp <= stack_page + THREAD_SIZE - 32)
return (struct pt_regs *)sp;
break;
}
pc = unwind_stack(task, &sp, pc, ra);
ra = 0;
} while (pc);
#else
save_raw_context_stack(sp);
#endif
return NULL;
}
/*
* Save stack-backtrace addresses into a stack_trace buffer.
*/
void save_stack_trace(struct stack_trace *trace, struct task_struct *task)
{
struct pt_regs dummyregs;
struct pt_regs *regs = &dummyregs;
WARN_ON(trace->nr_entries || !trace->max_entries);
if (task && task != current) {
regs->regs[29] = task->thread.reg29;
regs->regs[31] = 0;
regs->cp0_epc = task->thread.reg31;
} else {
if (!task)
task = current;
prepare_frametrace(regs);
}
while (1) {
regs = save_context_stack(trace, task, regs);
if (!regs || trace->nr_entries >= trace->max_entries)
break;
}
}
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