On Mon, Feb 25, 2019 at 10:11:24AM -0600, Josh Poimboeuf wrote: > On Mon, Feb 25, 2019 at 01:43:34PM +0100, Peter Zijlstra wrote:
> > -#define STACK_FRAME_NON_STANDARD(func) \ > > - static void __used __section(.discard.func_stack_frame_non_standard) \ > > - *__func_stack_frame_non_standard_##func = func > > +#define STACK_FRAME_NON_STANDARD(func) > > \ > > + asm (".pushsection .discard.nonstd_frame_strtab, \"S\", @3\n\t" \ > > + "999: .ascii \"" #func "\"\n\t" \ > > + " .byte 0\n\t" \ > > + ".popsection\n\t" \ > > + ".pushsection .discard.nonstd_frame\n\t" \ > > + ".long 999b - .\n\t" \ > > + ".popsection\n\t") > > + > > I don't think this will work in the case where GCC does an IPA > optimization and renames the function (e.g., renames func to > func.isra.1234), right? That might be a deal breaker... Or; as has been found by 0day; the whole function gets inlined and the symbol no longer exists at all. That's curable with a noinline, but all things considered, I think we should go back to the old horrible scheme. Andy?