linux/arch
Nick Desaulniers ffcf9c5700 x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments
Users of GNU ld (BFD) from binutils 2.39+ will observe multiple
instances of a new warning when linking kernels in the form:

  ld: warning: arch/x86/boot/pmjump.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
  ld: warning: arch/x86/boot/compressed/vmlinux has a LOAD segment with RWX permissions

Generally, we would like to avoid the stack being executable.  Because
there could be a need for the stack to be executable, assembler sources
have to opt-in to this security feature via explicit creation of the
.note.GNU-stack feature (which compilers create by default) or command
line flag --noexecstack.  Or we can simply tell the linker the
production of such sections is irrelevant and to link the stack as
--noexecstack.

LLVM's LLD linker defaults to -z noexecstack, so this flag isn't
strictly necessary when linking with LLD, only BFD, but it doesn't hurt
to be explicit here for all linkers IMO.  --no-warn-rwx-segments is
currently BFD specific and only available in the current latest release,
so it's wrapped in an ld-option check.

While the kernel makes extensive usage of ELF sections, it doesn't use
permissions from ELF segments.

Link: https://lore.kernel.org/linux-block/3af4127a-f453-4cf7-f133-a181cce06f73@kernel.dk/
Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=ba951afb99912da01a6e8434126b8fac7aa75107
Link: https://github.com/llvm/llvm-project/issues/57009
Reported-and-tested-by: Jens Axboe <axboe@kernel.dk>
Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-08-10 18:30:09 -07:00
..
alpha Bitmap patches for v6.0-rc1 2022-08-07 17:52:35 -07:00
arc Kbuild updates for v5.20 2022-08-10 10:40:41 -07:00
arm Pin control bulk changes for v6.0: 2022-08-10 11:01:44 -07:00
arm64 mm: hugetlb_vmemmap: delete hugetlb_optimize_vmemmap_enabled() 2022-08-08 18:06:42 -07:00
csky Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
hexagon Bitmap patches for v6.0-rc1 2022-08-07 17:52:35 -07:00
ia64 Bitmap patches for v6.0-rc1 2022-08-07 17:52:35 -07:00
loongarch - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
m68k Fixes include: 2022-08-09 09:39:25 -07:00
microblaze - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
mips TTY / Serial driver changes for 6.0-rc1 2022-08-08 11:31:40 -07:00
nios2 nios2: drop definition of PGD_ORDER 2022-07-17 17:14:43 -07:00
openrisc Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
parisc Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
powerpc cxl for 6.0 2022-08-10 11:07:26 -07:00
riscv Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
s390 Bitmap patches for v6.0-rc1 2022-08-07 17:52:35 -07:00
sh Bitmap patches for v6.0-rc1 2022-08-07 17:52:35 -07:00
sparc Bitmap patches for v6.0-rc1 2022-08-07 17:52:35 -07:00
um - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
x86 x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments 2022-08-10 18:30:09 -07:00
xtensa - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
.gitignore
Kconfig asm-generic: updates for 6.0 2022-08-05 10:07:23 -07:00