static enum stack_type
analyze_stack(int cpu, struct task_struct *task, unsigned long *stack,
unsigned long **stack_end, unsigned long *irq_stack,
unsigned *used, char **id)
{
unsigned long addr;
addr = ((unsigned long)stack & (~(THREAD_SIZE - 1)));
if ((unsigned long)task_stack_page(task) == addr)
return STACK_IS_NORMAL;
*stack_end = in_exception_stack(cpu, (unsigned long)stack,
used, id);
if (*stack_end)
return STACK_IS_EXCEPTION;
if (!irq_stack)
return STACK_IS_NORMAL;
*stack_end = irq_stack;
irq_stack = irq_stack - irq_stack_size;
if (in_irq_stack(stack, irq_stack, *stack_end))
return STACK_IS_IRQ;
return STACK_IS_UNKNOWN;
}
int get_stack_info(unsigned long *stack, struct task_struct *task,
struct stack_info *info, unsigned long *visit_mask)
{
if (!stack)
goto unknown;
task = task ? : current;
if (in_task_stack(stack, task, info))
goto recursion_check;
if (task != current)
goto unknown;
if (in_exception_stack(stack, info))
goto recursion_check;
if (in_irq_stack(stack, info))
goto recursion_check;
if (in_sysenter_stack(stack, info))
goto recursion_check;
goto unknown;
recursion_check:
/*
* Make sure we don't iterate through any given stack more than once.
* If it comes up a second time then there's something wrong going on:
* just break out and report an unknown stack type.
*/
if (visit_mask) {
if (*visit_mask & (1UL << info->type)) {
printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
goto unknown;
}
*visit_mask |= 1UL << info->type;
}
return 0;
unknown:
info->type = STACK_TYPE_UNKNOWN;
return -EINVAL;
}
/*
* We are returning from the irq stack and go to the previous one.
* If the previous stack is also in the irq stack, then bp in the first
* frame of the irq stack points to the previous, interrupted one.
* Otherwise we have another level of indirection: We first save
* the bp of the previous stack, then we switch the stack to the irq one
* and save a new bp that links to the previous one.
* (See save_args())
*/
static inline unsigned long
fixup_bp_irq_link(unsigned long bp, unsigned long *stack,
unsigned long *irq_stack, unsigned long *irq_stack_end)
{
#ifdef CONFIG_FRAME_POINTER
struct stack_frame *frame = (struct stack_frame *)bp;
unsigned long next;
if (!in_irq_stack(stack, irq_stack, irq_stack_end)) {
if (!probe_kernel_address(&frame->next_frame, next))
return next;
else
WARN_ONCE(1, "Perf: bad frame pointer = %p in "
"callchain\n", &frame->next_frame);
}
#endif
return bp;
}
void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack,
const struct stacktrace_ops *ops, void *data)
{
const unsigned cpu = get_cpu();
unsigned long *irq_stack_end =
(unsigned long *)per_cpu(irq_stack_ptr, cpu);
unsigned used = 0;
struct thread_info *tinfo;
int graph = 0;
unsigned long bp;
if (!task)
task = current;
if (!stack) {
unsigned long dummy;
stack = &dummy;
if (task && task != current)
stack = (unsigned long *)task->thread.sp;
}
bp = stack_frame(task, regs);
/*
* Print function call entries in all stacks, starting at the
* current stack address. If the stacks consist of nested
* exceptions
*/
tinfo = task_thread_info(task);
for (;;) {
char *id;
unsigned long *estack_end;
estack_end = in_exception_stack(cpu, (unsigned long)stack,
&used, &id);
if (estack_end) {
if (ops->stack(data, id) < 0)
break;
bp = ops->walk_stack(tinfo, stack, bp, ops,
data, estack_end, &graph);
ops->stack(data, "<EOE>");
/*
* We link to the next stack via the
* second-to-last pointer (index -2 to end) in the
* exception stack:
*/
stack = (unsigned long *) estack_end[-2];
continue;
}
if (irq_stack_end) {
unsigned long *irq_stack;
irq_stack = irq_stack_end -
(IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);
if (in_irq_stack(stack, irq_stack, irq_stack_end)) {
if (ops->stack(data, "IRQ") < 0)
break;
bp = ops->walk_stack(tinfo, stack, bp,
ops, data, irq_stack_end, &graph);
/*
* We link to the next stack (which would be
* the process stack normally) the last
* pointer (index -1 to end) in the IRQ stack:
*/
stack = (unsigned long *) (irq_stack_end[-1]);
bp = fixup_bp_irq_link(bp, stack, irq_stack,
irq_stack_end);
irq_stack_end = NULL;
ops->stack(data, "EOI");
continue;
}
}
break;
}
/*
* This handles the process stack:
*/
bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
put_cpu();
}
