[PATCH 3.16 09/86] jump_label: Allow jump labels to be used in assembly

Ben Hutchings
2019-05-16T16:03:48Z

From: Anton Blanchard <anton@samba.org>

commit c0ccf6f99e3a43b87980c9df7da48427885206d0 upstream.

To use jump labels in assembly we need the HAVE_JUMP_LABEL
define, so we select a fallback version if the toolchain does
not support them.

Modify linux/jump_label.h so it can be included by assembly
files. We also need to add -DCC_HAVE_ASM_GOTO to KBUILD_AFLAGS.

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: benh@kernel.crashing.org
Cc: catalin.marinas@arm.com
Cc: davem@davemloft.net
Cc: heiko.carstens@de.ibm.com
Cc: jbaron@akamai.com
Cc: linux@arm.linux.org.uk
Cc: linuxppc-dev@lists.ozlabs.org
Cc: liuj97@gmail.com
Cc: mgorman@suse.de
Cc: mmarek@suse.cz
Cc: mpe@ellerman.id.au
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: rostedt@goodmis.org
Cc: schwidefsky@de.ibm.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1428551492-21977-2-git-send-email-anton@samba.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
Makefile | 1 +
include/linux/jump_label.h | 21 +++++++++++++++++----
2 files changed, 18 insertions(+), 4 deletions(-)

--- a/Makefile
+++ b/Makefile
@@ -761,6 +761,7 @@ KBUILD_ARFLAGS := $(call ar-option,D)
# check for 'asm goto'
ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC)), y)
KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
+ KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
endif

include $(srctree)/scripts/Makefile.extrawarn
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -45,6 +45,12 @@
* same as using STATIC_KEY_INIT_FALSE.
*/

+#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+# define HAVE_JUMP_LABEL
+#endif
+
+#ifndef __ASSEMBLY__
+
#include <linux/types.h>
#include <linux/compiler.h>
#include <linux/bug.h>
@@ -55,7 +61,7 @@ extern bool static_key_initialized;
"%s used before call to jump_label_init", \
__func__)

-#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+#ifdef HAVE_JUMP_LABEL

struct static_key {
atomic_t enabled;
@@ -66,13 +72,18 @@ struct static_key {
#endif
};

-# include <asm/jump_label.h>
-# define HAVE_JUMP_LABEL
#else
struct static_key {
atomic_t enabled;
};
-#endif /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */
+#endif /* HAVE_JUMP_LABEL */
+#endif /* __ASSEMBLY__ */
+
+#ifdef HAVE_JUMP_LABEL
+#include <asm/jump_label.h>
+#endif
+
+#ifndef __ASSEMBLY__

enum jump_label_type {
JUMP_LABEL_DISABLE = 0,
@@ -223,3 +234,5 @@ static inline void static_key_disable(st
}

#endif /* _LINUX_JUMP_LABEL_H */
+
+#endif /* __ASSEMBLY__ */