[tip: core/build] arm64/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:     b3e5d80d0c48c0cc7bce56473672f4e6e1210910
Gitweb:        https://git.kernel.org/tip/b3e5d80d0c48c0cc7bce56473672f4e6e1210910
Author:        Kees Cook <keescook@xxxxxxxxxxxx>
AuthorDate:    Tue, 01 Sep 2020 19:53:43 -07:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Thu, 03 Sep 2020 10:28:35 +02:00

arm64/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.

With all sections now handled, enable orphan section warnings.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Will Deacon <will@xxxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200902025347.2504702-2-keescook@xxxxxxxxxxxx
---
 arch/arm64/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 6de7f55..081144f 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -29,6 +29,10 @@ LDFLAGS_vmlinux	+= --fix-cortex-a53-843419
   endif
 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 += $(call ld-option, --orphan-handling=warn)
+
 ifeq ($(CONFIG_ARM64_USE_LSE_ATOMICS), y)
   ifneq ($(CONFIG_ARM64_LSE_ATOMICS), y)
 $(warning LSE atomics not supported by binutils)