summaryrefslogtreecommitdiff
path: root/arch/um
diff options
context:
space:
mode:
authorDavid Gow <davidgow@google.com>2022-09-21 14:48:55 +0800
committerRichard Weinberger <richard@nod.at>2022-09-21 09:11:42 +0200
commitbd71558d585ac61cfd799db7f25e78dca404dd7a (patch)
treeaaedd4203aa026706bdab22038d0d6d35f56a78a /arch/um
parent2975e4a282964dd14831e4612ac1b6b10745e5ba (diff)
arch: um: Mark the stack non-executable to fix a binutils warning
Since binutils 2.39, ld will print a warning if any stack section is executable, which is the default for stack sections on files without a .note.GNU-stack section. This was fixed for x86 in commit ffcf9c5700e4 ("x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments"), but remained broken for UML, resulting in several warnings: /usr/bin/ld: warning: arch/x86/um/vdso/vdso.o: missing .note.GNU-stack section implies executable stack /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker /usr/bin/ld: warning: .tmp_vmlinux.kallsyms1 has a LOAD segment with RWX permissions /usr/bin/ld: warning: .tmp_vmlinux.kallsyms1.o: missing .note.GNU-stack section implies executable stack /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker /usr/bin/ld: warning: .tmp_vmlinux.kallsyms2 has a LOAD segment with RWX permissions /usr/bin/ld: warning: .tmp_vmlinux.kallsyms2.o: missing .note.GNU-stack section implies executable stack /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker /usr/bin/ld: warning: vmlinux has a LOAD segment with RWX permissions Link both the VDSO and vmlinux with -z noexecstack, fixing the warnings about .note.GNU-stack sections. In addition, pass --no-warn-rwx-segments to dodge the remaining warnings about LOAD segments with RWX permissions in the kallsyms objects. (Note that this flag is apparently not available on lld, so hide it behind a test for BFD, which is what the x86 patch does.) Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ffcf9c5700e49c0aee42dcba9a12ba21338e8136 Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=ba951afb99912da01a6e8434126b8fac7aa75107 Signed-off-by: David Gow <davidgow@google.com> Reviewed-by: Lukas Straub <lukasstraub2@web.de> Tested-by: Lukas Straub <lukasstraub2@web.de> Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/Makefile8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/um/Makefile b/arch/um/Makefile
index f2fe63bfd819..f1d4d67157be 100644
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -132,10 +132,18 @@ export LDS_ELF_FORMAT := $(ELF_FORMAT)
# The wrappers will select whether using "malloc" or the kernel allocator.
LINK_WRAPS = -Wl,--wrap,malloc -Wl,--wrap,free -Wl,--wrap,calloc
+# Avoid binutils 2.39+ warnings by marking the stack non-executable and
+# ignorning warnings for the kallsyms sections.
+LDFLAGS_EXECSTACK = -z noexecstack
+ifeq ($(CONFIG_LD_IS_BFD),y)
+LDFLAGS_EXECSTACK += $(call ld-option,--no-warn-rwx-segments)
+endif
+
LD_FLAGS_CMDLINE = $(foreach opt,$(KBUILD_LDFLAGS),-Wl,$(opt))
# Used by link-vmlinux.sh which has special support for um link
export CFLAGS_vmlinux := $(LINK-y) $(LINK_WRAPS) $(LD_FLAGS_CMDLINE)
+export LDFLAGS_vmlinux := $(LDFLAGS_EXECSTACK)
# When cleaning we don't include .config, so we don't include
# TT or skas makefiles and don't clean skas_ptregs.h.