[tip: core/build] x86/asm: Avoid generating unused kprobe sections

[tip-bot2 for Kees Cook]

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

Commit-ID:     a850958c072404f75dd41782cb4ff34b8625b47d
Gitweb:        https://git.kernel.org/tip/a850958c072404f75dd41782cb4ff34b8625b47d
Author:        Kees Cook <keescook@xxxxxxxxxxxx>
AuthorDate:    Fri, 21 Aug 2020 12:43:03 -07:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 01 Sep 2020 10:03:18 +02:00

x86/asm: Avoid generating unused kprobe sections

When !CONFIG_KPROBES, do not generate kprobe sections. This makes
sure there are no unexpected sections encountered by the linker scripts.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200821194310.3089815-23-keescook@xxxxxxxxxxxx
---
 arch/x86/include/asm/asm.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index 5c15f95..4712206 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -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 /* ! __ASSEMBLY__ */
 # define _EXPAND_EXTABLE_HANDLE(x) #x