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linux-next/arch/mips/kernel/stacktrace.c
Atsushi Nemoto 1924600cdb [MIPS] Make unwind_stack() can dig into interrupted context
If the PC was ret_from_irq or ret_from_exception, there will be no
more normal stackframe.  Instead of stopping the unwinding, use PC and
RA saved by an exception handler to continue unwinding into the
interrupted context.  This also simplifies the CONFIG_STACKTRACE code.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-10-01 23:16:59 +01:00

86 lines
1.9 KiB
C

/*
* 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 void 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;
if (raw_show_trace || !__kernel_text_address(pc)) {
unsigned long stack_page =
(unsigned long)task_stack_page(task);
if (stack_page && sp >= stack_page &&
sp <= stack_page + THREAD_SIZE - 32)
save_raw_context_stack(trace, sp);
return;
}
do {
if (trace->skip > 0)
trace->skip--;
else
trace->entries[trace->nr_entries++] = pc;
if (trace->nr_entries >= trace->max_entries)
break;
pc = unwind_stack(task, &sp, pc, &ra);
} while (pc);
#else
save_raw_context_stack(sp);
#endif
}
/*
* 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);
}
save_context_stack(trace, task, regs);
}