[PATCH 5.4 17/37] ARM: 8918/2: only build return_address() if needed

From: Greg Kroah-Hartman
Date: Fri Sep 10 2021 - 08:35:58 EST


From: Ben Dooks <ben-linux@xxxxxxxxx>

commit fb033c95c94ca1ee3d16e04ebdb85d65fb55fff8 upstream.

The system currently warns if the config conditions for
building return_address in arch/arm/kernel/return_address.c
are not met, leaving just an EXPORT_SYMBOL_GPL(return_address)
of a function defined to be 'static linline'.
This is a result of aeea3592a13b ("ARM: 8158/1: LLVMLinux: use static inline in ARM ftrace.h").

Since we're not going to build anything other than an exported
symbol for something that is already being defined to be an
inline-able return of NULL, just avoid building the code to
remove the following warning:

Fixes: aeea3592a13b ("ARM: 8158/1: LLVMLinux: use static inline in ARM ftrace.h")
Signed-off-by: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/kernel/Makefile | 6 +++++-
arch/arm/kernel/return_address.c | 4 ----
2 files changed, 5 insertions(+), 5 deletions(-)

--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -17,10 +17,14 @@ CFLAGS_REMOVE_return_address.o = -pg
# Object file lists.

obj-y := elf.o entry-common.o irq.o opcodes.o \
- process.o ptrace.o reboot.o return_address.o \
+ process.o ptrace.o reboot.o \
setup.o signal.o sigreturn_codes.o \
stacktrace.o sys_arm.o time.o traps.o

+ifneq ($(CONFIG_ARM_UNWIND),y)
+obj-$(CONFIG_FRAME_POINTER) += return_address.o
+endif
+
obj-$(CONFIG_ATAGS) += atags_parse.o
obj-$(CONFIG_ATAGS_PROC) += atags_proc.o
obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += atags_compat.o
--- a/arch/arm/kernel/return_address.c
+++ b/arch/arm/kernel/return_address.c
@@ -7,8 +7,6 @@
*/
#include <linux/export.h>
#include <linux/ftrace.h>
-
-#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
#include <linux/sched.h>

#include <asm/stacktrace.h>
@@ -53,6 +51,4 @@ void *return_address(unsigned int level)
return NULL;
}

-#endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */
-
EXPORT_SYMBOL_GPL(return_address);