On Wed, 18 Nov 2020 19:31:50 +0100 Florian Weimer <fw@xxxxxxxxxxxxx> wrote: > * Segher Boessenkool: > > > On Wed, Nov 18, 2020 at 12:17:30PM -0500, Steven Rostedt wrote: > >> I could change the stub from (void) to () if that would be better. > > > > Don't? In a function definition they mean exactly the same thing (and > > the kernel uses (void) everywhere else, which many people find clearer). > > And I think () functions expected a caller-provided parameter save > area on powerpc64le, while (void) functions do not. It does not > matter for an empty function, but GCC prefers to use the parameter > save area instead of setting up a stack frame if it is present. So > you get stack corruption if you call a () function as a (void) > function. (The other way round is fine.) I wonder if we should define on all architectures a void void_stub(void), in assembly, that just does a return, an not worry about gcc messing up the creation of the stub function. On x86_64: GLOBAL(void_stub) retq And so on. -- Steve
