On Tue, 2020-06-09 at 13:42 -0700, Kees Cook wrote: > On Tue, Jun 09, 2020 at 01:14:04PM -0700, Kristen Carlson Accardi > wrote: > > On Thu, 2020-05-21 at 14:33 -0700, Kees Cook wrote: > > > Oh! And I am reminded suddenly about CONFIG_FG_KASLR needing to > > > interact > > > correctly with CONFIG_LD_DEAD_CODE_DATA_ELIMINATION in that we do > > > NOT > > > want the sections to be collapsed at link time: > > > > sorry - I'm a little confused and was wondering if you could > > clarify > > something. Does this mean you expect CONFIG_FG_KASLR=y and > > CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y to be a valid config? I am > > not > > Yes, I don't see a reason they can't be used together. > > > familiar with the option, but it seems like you are saying that it > > requires sections to be collapsed, in which case both of these > > options > > as yes would not be allowed? Should I actively prevent this in the > > Kconfig? > > No, I'm saying that CONFIG_LD_DEAD_CODE_DATA_ELIMINATION does _not_ > actually require that the sections be collapsed, but the Makefile > currently does this just to keep the resulting ELF "tidy". We want > that disabled (for the .text parts) in the case of CONFIG_FG_KASLR. > The > dead code elimination step, is, IIUC, done at link time before the > output sections are written. > Ah ok, that makes sense. Thanks.
