kbuild: Disable CONFIG_LD_ORPHAN_WARN for ld.lld 10.0.1

ld.lld 10.0.1 spews a bunch of various warnings about .rela sections,
along with a few others. Newer versions of ld.lld do not have these
warnings. As a result, do not add '--orphan-handling=warn' to
LDFLAGS_vmlinux if ld.lld's version is not new enough.

Link: https://github.com/ClangBuiltLinux/linux/issues/1187
Link: https://github.com/ClangBuiltLinux/linux/issues/1193
Reported-by: Arvind Sankar <nivedita@alum.mit.edu>
Reported-by: kernelci.org bot <bot@kernelci.org>
Reported-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

diff --git a/MAINTAINERS b/MAINTAINERS
index a008b70..286ed8e 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4274,6 +4274,7 @@ B:        https://github.com/ClangBuiltLinux/linux/issues
 C:     irc://chat.freenode.net/clangbuiltlinux
 F:     Documentation/kbuild/llvm.rst
 F:     scripts/clang-tools/
+F:     scripts/lld-version.sh
 K:     \b(?i:clang|llvm)\b
 
 CLEANCACHE API

diff --git a/init/Kconfig b/init/Kconfig
index 92c58b4..b9037d6 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -47,6 +47,10 @@ config CLANG_VERSION
        int
        default $(shell,$(srctree)/scripts/clang-version.sh $(CC))
 
+config LLD_VERSION
+       int
+       default $(shell,$(srctree)/scripts/lld-version.sh $(LD))
+
 config CC_CAN_LINK
        bool
        default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag)) if 64BIT
@@ -1351,6 +1355,7 @@ config LD_DEAD_CODE_DATA_ELIMINATION
 config LD_ORPHAN_WARN
        def_bool y
        depends on ARCH_WANT_LD_ORPHAN_WARN
+       depends on !LD_IS_LLD || LLD_VERSION >= 110000
        depends on $(ld-option,--orphan-handling=warn)
 
 config SYSCTL

diff --git a/scripts/lld-version.sh b/scripts/lld-version.sh
new file mode 100755 (executable)
index 0000000..d70edb4
--- /dev/null
+++ b/scripts/lld-version.sh
@@ -0,0 +1,20 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Usage: $ ./scripts/lld-version.sh ld.lld
+#
+# Print the linker version of `ld.lld' in a 5 or 6-digit form
+# such as `100001' for ld.lld 10.0.1 etc.
+
+linker_string="$($* --version)"
+
+if ! ( echo $linker_string | grep -q LLD ); then
+       echo 0
+       exit 1
+fi
+
+VERSION=$(echo $linker_string | cut -d ' ' -f 2)
+MAJOR=$(echo $VERSION | cut -d . -f 1)
+MINOR=$(echo $VERSION | cut -d . -f 2)
+PATCHLEVEL=$(echo $VERSION | cut -d . -f 3)
+printf "%d%02d%02d\\n" $MAJOR $MINOR $PATCHLEVEL