On Sat, Oct 06, 2018 at 09:39:05AM -0400, Steven Rostedt wrote: > On Sat, 6 Oct 2018 14:12:11 +0200 > Peter Zijlstra <pet...@infradead.org> wrote: > > > On Fri, Oct 05, 2018 at 09:51:11PM -0400, Steven Rostedt wrote: > > > +#define arch_dynfunc_trampoline(name, def) \ > > > + asm volatile ( \ > > > + ".globl dynfunc_" #name "; \n\t" \ > > > + "dynfunc_" #name ": \n\t" \ > > > + "jmp " #def " \n\t" \ > > > + ".balign 8 \n \t" \ > > > + : : : "memory" ) > > > > Bah, what is it with you people and trampolines. Why can't we, just like > > jump_label, patch the call directly? > > > > The whole call+jmp thing is silly, don't do that. It just wrecks I$ and > > is slower for no real reason afaict. > > My first attempt was to do just that. But to add a label at the > call site required handling all the parameters too. See my branch: > ftrace/jump_function-v1 for how ugly it got (and it didn't work).
Can't we hijack the relocation records for these functions before they get thrown out in the (final) link pass or something?
