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[MIPS] Make unwind_stack() can dig into interrupted context

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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>
This commit is contained in:
Atsushi Nemoto
2006-09-29 18:02:51 +09:00
committed by Ralf Baechle
parent 23126692e3
commit 1924600cdb
4 changed files with 39 additions and 34 deletions
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32
arch/mips/kernel/stacktrace.c
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@@ -31,23 +31,21 @@ static void save_raw_context_stack(struct stack_trace *trace,
}
}
static struct pt_regs * save_context_stack(struct stack_trace *trace,
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;
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)) {
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 NULL;
return;
}
do {
if (trace->skip > 0)
@@ -56,25 +54,11 @@ static struct pt_regs * save_context_stack(struct stack_trace *trace,
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;
pc = unwind_stack(task, &sp, pc, &ra);
} while (pc);
#else
save_raw_context_stack(sp);
#endif
return NULL;
}
/*
@@ -97,9 +81,5 @@ void save_stack_trace(struct stack_trace *trace, struct task_struct *task)
prepare_frametrace(regs);
}
while (1) {
regs = save_context_stack(trace, task, regs);
if (!regs || trace->nr_entries >= trace->max_entries)
break;
}
save_context_stack(trace, task, regs);
}