On Mon, Jul 2, 2018 at 11:55 AM, Christoph von Recklinghausen <crecklin@xxxxxxxxxx> wrote: > On 07/02/2018 02:43 PM, Kees Cook wrote: >> On Sat, Jun 30, 2018 at 1:43 PM, Christoph von Recklinghausen >> <crecklin@xxxxxxxxxx> wrote: >>> The last issue I'm chasing is build failures on ARCH=m68k. The error is >>> atomic_read and friends needed by the jump label code not being found. >>> The config has CONFIG_BROKEN_ON_SMP=y, so the jump label calls I added >>> will only be made #ifndef CONFIG_BROKEN_ON_SMP. Do you think that's >>> worth a mention in the blurb that's added to >>> Documentation/admin-guide/kernel-parameters.txt? >> Uhm, that's weird -- I think the configs on m68k need fixing then? I >> don't want to have to sprinkle that ifdef in generic code. >> >> How are other users of static keys and jump labels dealing with m68k weirdness? >> > There's also CONFIG_JUMP_LABEL which is defined in x86_64 but not > defined in the m68k configs. I'll use that instead. In hindsight I > should have spotted that but didn't. I think what I mean is that jump labels should always work. There shouldn't be a need to #ifdef the common usercopy code. i.e. include/linux/jump_label.h should work on all architectures already. I see HAVE_JUMP_LABEL tests there, for example: #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) # define HAVE_JUMP_LABEL #endif Other core code uses static keys without this; what is the failing combination? -Kees -- Kees Cook Pixel Security
