Messages in this thread | | | Date | Fri, 19 Aug 2022 21:52:40 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH 1/9] LoongArch/ftrace: Add basic support |
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On Sat, 20 Aug 2022 09:38:21 +0800 Jinyang He <hejinyang@loongson.cn> wrote:
> I think we have implemented CONFIG_FTRACE_WITH_ARGS in dynamic ftrace > in the [Patch3/9].
Sorry, I must have missed it.
> But, for non dynamic ftrace, it is hardly to > implement it. Because the LoongArch compiler gcc treats mount as a
Don't bother implementing it for non-dynamic. I would just add a:
config HAVE_FTRACE_WITH_ARGS if DYNAMIC_FTRACE
and be done with it.
> really call, like 'call _mcount(__builtin_return_address(0))'. That > means, they decrease stack, save args to callee saved regs and may > do some optimization before calling mcount. It is difficult to find the > original args and apply changes from tracers.
Right, there's no point in implementing it for non dynamic. Like I said, non-dynamic is just a stepping stone for getting dynamic working. Once you have dynamic working, it's up to you to throw out the non-dynamic. It's not useful for anything other than porting to a new architecture or for academic purposes.
-- Steve
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