[PATCH 1/2] jump_label: Allow jump labels to be used in assembly

From: Anton Blanchard
Date: Tue Jan 06 2015 - 05:20:37 EST


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@xxxxxxxxx>
---
Makefile | 1 +
include/linux/jump_label.h | 21 +++++++++++++++++----
2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index ef748e1..7b83c3f 100644
--- a/Makefile
+++ b/Makefile
@@ -774,6 +774,7 @@ 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
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 98f923b6..f4de473 100644
--- 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,
@@ -203,3 +214,5 @@ static inline bool static_key_enabled(struct static_key *key)
}

#endif /* _LINUX_JUMP_LABEL_H */
+
+#endif /* __ASSEMBLY__ */
--
2.1.0

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