linux/arch/x86/boot
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
..
compressed x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments 2022-08-10 18:30:09 -07:00
tools x86/build: Declutter the build output 2020-08-20 08:17:40 +02:00
.gitignore x86/boot: Modernize genimage script; hdimage+EFI support 2021-05-10 12:27:50 +02:00
a20.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
apm.c x86/boot: Fix comment spelling 2020-03-17 20:52:52 +01:00
bioscall.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 83 2019-05-24 17:37:52 +02:00
bitops.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
boot.h - Add a "make x86_debug.config" target which enables a bunch of useful 2022-05-23 18:15:44 -07:00
cmdline.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
copy.S x86/asm: Do not annotate functions with GLOBAL 2019-10-18 11:25:58 +02:00
cpu.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
cpucheck.c x86/boot: Use MSR read/write helpers instead of inline assembly 2022-04-06 13:02:13 +02:00
cpuflags.c x86/tdx: Detect TDX at early kernel decompression time 2022-04-07 08:27:51 -07:00
cpuflags.h x86/tdx: Detect TDX at early kernel decompression time 2022-04-07 08:27:51 -07:00
ctype.h
early_serial_console.c x86: Clean up 'sizeof x' => 'sizeof(x)' 2018-10-29 07:13:28 +01:00
edd.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
genimage.sh x86/boot: Fix make hdimage with older versions of mtools 2021-09-29 11:06:47 +02:00
header.S efi: x86: Fix config name for setting the NX-compatibility flag in the PE header 2022-06-01 14:07:48 +02:00
install.sh kbuild: factor out the common installation code into scripts/install.sh 2022-05-11 21:45:53 +09:00
io.h x86/boot: Port I/O: Allow to hook up alternative helpers 2022-04-07 08:27:52 -07:00
main.c - Add a "make x86_debug.config" target which enables a bunch of useful 2022-05-23 18:15:44 -07:00
Makefile x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments 2022-08-10 18:30:09 -07:00
memory.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
mkcpustr.c x86/cpu: Print VMX flags in /proc/cpuinfo using VMX_FEATURES_* 2020-01-13 18:36:02 +01:00
msr.h x86/boot: Introduce helpers for MSR reads/writes 2022-04-06 12:59:17 +02:00
mtools.conf.in x86/boot: Fix make hdimage with older versions of mtools 2021-09-29 11:06:47 +02:00
pm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
pmjump.S x86/asm: Do not annotate functions with GLOBAL 2019-10-18 11:25:58 +02:00
printf.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
regs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 83 2019-05-24 17:37:52 +02:00
setup.ld x86/boot: Add .text.* to setup.ld 2020-08-14 12:52:35 +02:00
string.c x86/boot: Add kstrtoul() from lib/ 2020-05-04 15:19:07 +02:00
string.h x86/boot/string: Add missing function prototypes 2021-12-10 19:49:06 +01:00
tty.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
version.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
vesa.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 48 2019-05-24 17:27:13 +02:00
video-bios.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
video-mode.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
video-vesa.c sysfb: Enable boot time VESA graphic mode selection 2022-03-04 20:55:33 +01:00
video-vga.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
video.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
video.h treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00