Messages in this thread | | | Date | Thu, 21 Apr 2022 08:37:58 -0400 | From | Steven Rostedt <> | Subject | Re: [RFC PATCH -next v2 0/4] arm64/ftrace: support dynamic trampoline |
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On Thu, 21 Apr 2022 09:13:01 +0800 "Wangshaobo (bobo)" <bobo.shaobowang@huawei.com> wrote:
> Not yet, Steve, ftrace_location() looks has no help to find a right > rec->ip in our case, > > ftrace_location() can find a right rec->ip when input ip is in the range > between > > sym+0 and sym+$end, but our question is how to identify rec->ip from > __mcount_loc,
Are you saying that the "ftrace location" is not between sym+0 and sym+$end?
> > this changed the patchable entry before bti to after in gcc: > > [1] https://reviews.llvm.org/D73680 > > gcc tells the place of first nop of the 5 NOPs when using > -fpatchable-function-entry=5,3, > > but not tells the first nop after bti, so we don't know how to adjust > our rec->ip for ftrace.
OK, so I do not understand how the compiler is injecting bti with mcount calls, so I'll just walk away for now ;-)
-- Steve
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