Re: [Xen-devel] [Patch][0/2]implement dump_execution_state() on ia64

[Akio Takebe <takebe_akio@jp.fujitsu.com>]

Hi,

>On 27/3/08 16:56, "Akio Takebe" <takebe_akio@jp.fujitsu.com> wrote:
>
>>> Can you carefully explain why the interface changes are required?
>>> 
>> IA64 needs unwind infomation to show the Calltrace.
>> To make the unwind infomation, we needs switch stack and pt_regs.
>> So if possible, I want to use pt_regs at geting a interrupt.
>> 
>> I make many interface change because debug-key use IPI.
>> But I just want to use pt_regs.
>
>There is already a function which does what you want (i.e., takes a
>cpu_user_regs pointer) -- it's called show_execution_state().
>
>On x86 we implement dump_execution_state() by forcing an exception (by
>executing an invalid opcode) and dumping the calltrace from within the
>exception handler. This works because the exception handler has a
>cpu_user_regs pointer and hence can call show_execution_state(). We use the
>same trick for handling BUG() and ASSERT(). The code concerned is in
>arch/x86/traps.c:do_invalid_op().
On x86, does "xm debug-key d" make system hang?
Or it just uses the exception handler, not hangup?

Best Regards,

Akio Takebe