[tip: core/build] x86/build: Warn on orphan section placement

[tip-bot2 for Kees Cook]

The following commit has been merged into the core/build branch of tip:

Commit-ID:     83109d5d5fba7abf362f5a443c9f4c4ea10bbc8d
Gitweb:        https://git.kernel.org/tip/83109d5d5fba7abf362f5a443c9f4c4ea10bbc8d
Author:        Kees Cook <keescook@xxxxxxxxxxxx>
AuthorDate:    Tue, 01 Sep 2020 19:53:46 -07:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Thu, 03 Sep 2020 10:28:36 +02:00

x86/build: Warn on orphan section placement

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker script.

Now that all sections are explicitly handled, enable orphan section
warnings.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200902025347.2504702-5-keescook@xxxxxxxxxxxx
---
 arch/x86/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 4346ffb..154259f 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -209,6 +209,10 @@ ifdef CONFIG_X86_64
 LDFLAGS_vmlinux += -z max-page-size=0x200000
 endif
 
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
 archscripts: scripts_basic
 	$(Q)$(MAKE) $(build)=arch/x86/tools relocs