On 8/3/22 10:51 AM, Nick Desaulniers wrote: > On Wed, Aug 3, 2022 at 9:26 AM Linus Torvalds > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: >> >> On Wed, Aug 3, 2022 at 8:16 AM Jens Axboe <axboe@xxxxxxxxx> wrote: >>> >>> On the topic of warnings, on my new build box I get a lot of these: >>> >>> ld: warning: arch/x86/lib/putuser.o: missing .note.GNU-stack section implies executable stack >>> ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker >>> >>> which ends up polluting the output quite a bit. >>> >>> axboe@r7525 ~> ld --version >>> GNU ld (GNU Binutils for Debian) 2.38.90.20220713 >> >> Ok, I have binutils 2.37, so it may be new to 2.38. >> >> Some googling around seems to imply that we'd need to so something like this >> >> .section .note.GNU-stack,"",%progbits >> >> in all our *.S files. >> >> We do have some signs of that in our tooling, because apparently it >> has hit user-space, but I wonder what has triggered the need on the >> kernel side for you. >> >> I'd hate to add that pointless line to every asm file, but maybe we >> could so something like this >> >> #ifdef __ASSEMBLY_ >> #ifdef OUTPUT_PROGBITS >> .section .note.GNU-stack,"",%progbits >> #undef OUTPUT_PROGBITS >> #endif >> #endif >> >> and then change our 'AS' command line to do '-DOUTPUT_PROGBITS' in our >> makefiles. >> >> *Most* asm files should include <linux/linkage.h> just for all the >> macros that declare variables externally, so that might catch the bulk >> of it. >> >> Somebody who knows the rules better than I would be a good idea. > > $ as --help | grep exec > --execstack require executable stack for this object > --noexecstack don't require executable stack for this object > --statistics print various measured statistics from execution > > Does adding `--noexecstack` to KBUILD_ASFLAGS for these architectures > help, rather than modifying every assembler source? I can try whatever here, but a quick grep doesn't find anything for KBUILD_ASFLAGS or anything close to it. What am I missing? -- Jens Axboe
