acrn-kernel/arch/x86
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
..
boot x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments 2022-08-10 18:30:09 -07:00
coco
configs
crypto SPDX changes for 6.0-rc1 2022-08-04 12:12:54 -07:00
entry x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments 2022-08-10 18:30:09 -07:00
events ARM: 2022-08-04 14:59:54 -07:00
hyperv ARM: 2022-08-04 14:59:54 -07:00
ia32
include More from the CPU vulnerability nightmares front: 2022-08-09 09:29:07 -07:00
kernel More from the CPU vulnerability nightmares front: 2022-08-09 09:29:07 -07:00
kvm More from the CPU vulnerability nightmares front: 2022-08-09 09:29:07 -07:00
lib
math-emu
mm mm/hugetlb: make pud_huge() and follow_huge_pud() aware of non-present pud entry 2022-08-08 18:06:43 -07:00
net
pci
platform Bitmap patches for v6.0-rc1 2022-08-07 17:52:35 -07:00
power
purgatory
ras
realmode
tools
um Misc fixes: 2022-08-06 17:45:37 -07:00
video
virt/vmx/tdx
xen
.gitignore
Kbuild
Kconfig - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
Kconfig.assembler
Kconfig.cpu
Kconfig.debug
Makefile
Makefile.um
Makefile_32.cpu