On Wed, Jan 08, 2020 at 11:23:03AM +0100, Ard Biesheuvel wrote: > Eliminate all GOT entries in the decompressor binary, by forcing hidden > visibility for all symbol references, which informs the compiler that > such references will be resolved at link time without the need for > allocating GOT entries. > > To ensure that no GOT entries will creep back in, add an assertion to > the decompressor linker script that will fire if the .got section has > a non-zero size. > > Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > --- > arch/x86/boot/compressed/Makefile | 1 + > arch/x86/boot/compressed/hidden.h | 19 +++++++++++++++++++ > arch/x86/boot/compressed/vmlinux.lds.S | 1 + > 3 files changed, 21 insertions(+) > > diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile > index 56aa5fa0a66b..361df91b2288 100644 > --- a/arch/x86/boot/compressed/Makefile > +++ b/arch/x86/boot/compressed/Makefile > @@ -39,6 +39,7 @@ KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) > KBUILD_CFLAGS += $(call cc-disable-warning, gnu) > KBUILD_CFLAGS += -Wno-pointer-sign > KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) > +KBUILD_CFLAGS += -include hidden.h > This should be added to drivers/firmware/efi/libstub as well in case future code changes bring in global references there?
