linux/arch/x86/boot/compressed
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
..
.gitignore
acpi.c x86/boot: Add an efi.h header for the decompressor 2022-04-17 21:15:49 +02:00
cmdline.c
cpuflags.c x86/sev-es: Check required CPU features for SEV-ES 2020-09-10 21:49:25 +02:00
early_serial_console.c x86/boot: Put globals that are accessed early into the .data section 2022-04-20 20:10:54 +02:00
efi.c x86/boot: Add an efi.h header for the decompressor 2022-04-17 21:15:49 +02:00
efi.h x86/boot: Add an efi.h header for the decompressor 2022-04-17 21:15:49 +02:00
efi_thunk_64.S - Get rid of all the .fixup sections because this generates 2022-01-12 16:31:19 -08:00
error.c
error.h
head_32.S x86: clean up symbol aliasing 2022-02-22 16:21:34 +00:00
head_64.S Intel Trust Domain Extensions 2022-05-23 17:51:12 -07:00
ident_map_64.c x86/compressed/64: Add identity mappings for setup_data entries 2022-07-06 11:23:39 +02:00
idt_64.c x86/sev: Check SEV-SNP features support 2022-04-06 13:10:23 +02:00
idt_handlers_64.S
kaslr.c x86/boot: Add an efi.h header for the decompressor 2022-04-17 21:15:49 +02:00
kernel_info.S
Makefile x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments 2022-08-10 18:30:09 -07:00
mem_encrypt.S x86/compressed/64: Detect/setup SEV/SME features earlier during boot 2022-04-06 13:02:21 +02:00
misc.c Intel Trust Domain Extensions 2022-05-23 17:51:12 -07:00
misc.h Intel Trust Domain Extensions 2022-05-23 17:51:12 -07:00
mkpiggy.c
pgtable.h x86/boot: Avoid #VE during boot for TDX platforms 2022-04-07 08:27:53 -07:00
pgtable_64.c x86/boot: Add an efi.h header for the decompressor 2022-04-17 21:15:49 +02:00
sev.c x86/sev: Use firmware-validated CPUID for SEV-SNP guests 2022-04-07 16:47:12 +02:00
string.c
tdcall.S x86/boot: Port I/O: Add decompression-time support for TDX 2022-04-07 08:27:52 -07:00
tdx.c x86/boot: Port I/O: Add decompression-time support for TDX 2022-04-07 08:27:52 -07:00
tdx.h x86/tdx: Detect TDX at early kernel decompression time 2022-04-07 08:27:51 -07:00
vmlinux.lds.S