@@ -51,6 +51,10 @@ ifdef CONFIG_X86_NEED_RELOCS
LDFLAGS_vmlinux := --emit-relocs --discard-none
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 += --orphan-handling=warn
+
#
# Prevent GCC from generating any FP code by mistake.
#
@@ -138,11 +138,15 @@
# define _ASM_EXTABLE_FAULT(from, to) \
_ASM_EXTABLE_HANDLE(from, to, ex_handler_fault)
-# define _ASM_NOKPROBE(entry) \
+# ifdef CONFIG_KPROBES
+# define _ASM_NOKPROBE(entry) \
.pushsection "_kprobe_blacklist","aw" ; \
_ASM_ALIGN ; \
_ASM_PTR (entry); \
.popsection
+# else
+# define _ASM_NOKPROBE(entry)
+# endif
#else
# define _EXPAND_EXTABLE_HANDLE(x) #x
@@ -413,6 +413,12 @@ SECTIONS
ELF_DETAILS
DISCARDS
+ /DISCARD/ : {
+ *(.rela.*) *(.rela_*)
+ *(.rel.*) *(.rel_*)
+ *(.got) *(.got.*)
+ *(.igot.*) *(.iplt)
+ }
}
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 named in the linker script. Discards the unused rela, plt, and got sections that are not needed in the final vmlinux, stop emitting kprobe sections without kprobes, and enable orphan section warnings. Signed-off-by: Kees Cook <keescook@chromium.org> --- arch/x86/Makefile | 4 ++++ arch/x86/include/asm/asm.h | 6 +++++- arch/x86/kernel/vmlinux.lds.S | 6 ++++++ 3 files changed, 15 insertions(+), 1 deletion(-)