Re: arch/arm/probes/kprobes/core.c:409:30: error: .fnstart must precede .save or .vsave directives

From: Nick Desaulniers
Date: Mon Sep 26 2022 - 14:21:37 EST


On Mon, Sep 26, 2022 at 11:02 AM Russell King (Oracle)
<linux@xxxxxxxxxxxxxxx> wrote:
>
> On Mon, Sep 26, 2022 at 10:42:45AM -0700, Nick Desaulniers wrote:
> > > On Mon, Sep 26, 2022 at 08:44:05AM -0700, Nathan Chancellor wrote:
> > > > Thank you for the testing and report! I brought this up on GitHub on
> > > > Friday as I noticed this as well:
> > > >
> > > > https://github.com/ClangBuiltLinux/linux/issues/1718
> >
> > Thanks for the reports. I'll take a look at filing additional bug
> > reports against clang, then moving the definition of
> > __kretprobe_trampoline to out of line assembler.
>
> Are you saying that .save should be accepted without a .fnstart?

No. It's just a bug in clang's inline assembler. But it does make
sense to just move it to out of line assembler anyways; having it be
inline provides little to no benefit.

Should I be using UNWIND from arch/arm/include/asm/unwind.h on these
.fnstart/.save/.pad/.fnend directives?
--
Thanks,
~Nick Desaulniers