On Wed, Jul 19, 2017 at 03:50:14PM -0700, Kees Cook wrote: > >> > }) > >> > + > >> > +#define ASM_UNREACHABLE \ > >> > + "999: .pushsection .discard.unreachable\n\t" \ > >> > + ".long 999b - .\n\t" \ > >> > + ".popsection\n\t" > >> > >> Just so I understand, we'll get a single byte added for each exception > >> case, but it'll get discarded during final link? > > > > I think it's four bytes actually, but yeah, the section gets stripped at > > vmlinux link time. > > Right, yes. > > BTW, I think this needs compiler.h coverage instead of the #else in > compiler-gcc.h (since it's different from how annotate_unreachable is > used only in compiler-gcc.h. I'll adjust. Ah, right. Sounds good. > Also, in looking at CONFIG_STACK_VALIDATION, do you want it to just > warn and skip, or do you want to error out the build if validation > isn't available but it's in the .config? I think the current warn and skip behavior is fine. It's usually not a life-or-death matter, and if it is, you'll be checking the warnings anyway. -- Josh
