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authorNathan Chancellor <natechancellor@gmail.com>2020-11-19 23:46:56 +0300
committerMasahiro Yamada <masahiroy@kernel.org>2020-12-01 16:45:36 +0300
commit59612b24f78a0b61fe078ec9dff2e48e9cec52c0 (patch)
tree27ef4914a69c9bc3cd88fab6d3a6f6c10d5d91d0 /Makefile
parentb8a9092330da2030496ff357272f342eb970d51b (diff)
downloadlinux-59612b24f78a0b61fe078ec9dff2e48e9cec52c0.tar.xz
kbuild: Hoist '--orphan-handling' into Kconfig
Currently, '--orphan-handling=warn' is spread out across four different architectures in their respective Makefiles, which makes it a little unruly to deal with in case it needs to be disabled for a specific linker version (in this case, ld.lld 10.0.1). To make it easier to control this, hoist this warning into Kconfig and the main Makefile so that disabling it is simpler, as the warning will only be enabled in a couple places (main Makefile and a couple of compressed boot folders that blow away LDFLAGS_vmlinx) and making it conditional is easier due to Kconfig syntax. One small additional benefit of this is saving a call to ld-option on incremental builds because we will have already evaluated it for CONFIG_LD_ORPHAN_WARN. To keep the list of supported architectures the same, introduce CONFIG_ARCH_WANT_LD_ORPHAN_WARN, which an architecture can select to gain this automatically after all of the sections are specified and size asserted. A special thanks to Kees Cook for the help text on this config. Link: https://github.com/ClangBuiltLinux/linux/issues/1187 Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile6
1 files changed, 6 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index ae1592c1f5d6..8327725e5d76 100644
--- a/Makefile
+++ b/Makefile
@@ -986,6 +986,12 @@ ifeq ($(CONFIG_RELR),y)
LDFLAGS_vmlinux += --pack-dyn-relocs=relr
endif
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+ifdef CONFIG_LD_ORPHAN_WARN
+LDFLAGS_vmlinux += --orphan-handling=warn
+endif
+
# Align the bit size of userspace programs with the kernel
KBUILD_USERCFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
KBUILD_USERLDFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))