On Wed, Jun 24, 2020 at 02:48:55PM +0100, Dave Martin wrote: > On Wed, Jun 24, 2020 at 12:26:47PM +0100, Will Deacon wrote: > > On Wed, Jun 24, 2020 at 12:46:32PM +0200, Ard Biesheuvel wrote: > > > On Wed, 24 Jun 2020 at 12:44, Will Deacon <will@xxxxxxxxxx> wrote: > > > > For the kernel Image, how do we remove these sections? The objcopy flags > > > > in arch/arm64/boot/Makefile look both insufficient and out of date. My > > > > vmlinux ends up with both a ".notes" and a ".init.note.gnu.property" > > > > segment. > > > > > > The latter is the fault of the libstub make rules, that prepend .init > > > to all section names. > > > > Hmm. I tried adding -mbranch-protection=none to arm64 cflags for the stub, > > but I still see this note in vmlinux. It looks like it comes in via the > > stub copy of lib-ctype.o, but I don't know why that would force the > > note. The cflags look ok to me [1] and I confirmed that the note is > > being generated by the compiler. > > > > > I'm not sure if there is a point to having PAC and/or BTI in the EFI > > > stub, given that it runs under the control of the firmware, with its > > > memory mappings and PAC configuration etc. > > > > Agreed, I just can't figure out how to get rid of the note. > > Because this section is generated by the linker itself I think you might > have to send it to /DISCARD/ in the link, or strip it explicitly after > linking. Right, but why is the linker generating that section in the first place? I'm compiling with -mbranch-protection=none and all the other objects linked into the stub do not have the section. I wonder if it's because lib/ctype.c doesn't have any executable code... Will
