[Question] How to save_stack_trace_tsk_reliable() on mips?

[Jinyang He <hejinyang@loongson.cn>]

Hi, all,

Excuse me. Here is a question mail. How to get a reliable stack
of tasks on mips?

First, why save_stack_trace_tsk() to get stack is unreliable? Is it
because the asm code does not obey with gcc's stack rules, or others?

Secondly, can we use some methods to make the task stack reliable? For
example, use the fp register, can this method work? But it seems make
no sense for asm code unless each asm code do some fp work.

I found that the powerpc implemented save_stack_trace_tsk_reliable(),
and the x86 and s390 implemented the arch_stack_walk_reliable(). x86
implemented it through ORC unwind. For powerpc, it may implement it
through its ABI (I guess, I'm not familiar with them). Do we have a
chance to implement it in some way?

Finally, I found that some emails related to ORC unwind on ARM from the
livepatch mail list. It is difficult for me to understand. Is anyone
interested in ORC unwind on MIPS and have researched it?

Any comment is welcome. :-)

Thanks!