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

Subsystems: kernel build + files below scripts/ (unless maintained elsewhere), static branch/call, the rest

STALE4270d

5 messages, 3 authors, 2015-01-07 · open the first message on its own page

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

From: Anton Blanchard <hidden>
Date: 2015-01-06 10:20:35

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 <redacted>
---
 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

[PATCH 2/2] powerpc: Include linux/jump_label.h to get HAVE_JUMP_LABEL define

From: Anton Blanchard <hidden>
Date: 2015-01-06 10:20:50

Commit 1bc9e47aa8e4 ("powerpc/jump_label: Use HAVE_JUMP_LABEL")
converted uses of CONFIG_JUMP_LABEL to HAVE_JUMP_LABEL in
some assembly files.

HAVE_JUMP_LABEL is defined in linux/jump_label.h, so we need to
include this or we always get the non jump label fallback code.

Fixes: 1bc9e47aa8e4 ("powerpc/jump_label: Use HAVE_JUMP_LABEL")
Signed-off-by: Anton Blanchard <redacted>
---
 arch/powerpc/platforms/pseries/hvCall.S | 2 +-
 arch/powerpc/platforms/pseries/lpar.c   | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/hvCall.S b/arch/powerpc/platforms/pseries/hvCall.S
index ccd53f9..74b5b8e 100644
--- a/arch/powerpc/platforms/pseries/hvCall.S
+++ b/arch/powerpc/platforms/pseries/hvCall.S

@@ -7,12 +7,12 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */
+#include <linux/jump_label.h>
 #include <asm/hvcall.h>
 #include <asm/processor.h>
 #include <asm/ppc_asm.h>
 #include <asm/asm-offsets.h>
 #include <asm/ptrace.h>
-#include <asm/jump_label.h>
 
 	.section	".text"

diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 469751d..14ac1ad 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c

@@ -27,6 +27,7 @@
 #include <linux/console.h>
 #include <linux/export.h>
 #include <linux/static_key.h>
+#include <linux/jump_label.h>
 #include <asm/processor.h>
 #include <asm/mmu.h>
 #include <asm/page.h>

-- 
2.1.0

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

From: Jason Baron <jbaron@akamai.com>
Date: 2015-01-06 15:46:57

On 01/06/2015 05:20 AM, Anton Blanchard wrote:

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 <redacted>

(adding Steven)

Acked-by: Jason Baron <jbaron@akamai.com>

The jump label stuff often gets picked up by Steve, but I guess this
could go through the powerpc tree as well...

Thanks,

-Jason

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

From: Steven Rostedt <rostedt@goodmis.org>
Date: 2015-01-06 17:48:41

On Tue, Jan 06, 2015 at 09:20:27PM +1100, Anton Blanchard wrote:

quoted hunk

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 <redacted>
---
 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

Have you tested this on other archs? Because just looking at x86, it doesn't
seem that asm/jump_label.h can handle being called in assembly.

-- Steve

quoted hunk

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

From: Anton Blanchard <hidden>
Date: 2015-01-07 10:34:35

Hi Steve,

Have you tested this on other archs? Because just looking at x86, it
doesn't seem that asm/jump_label.h can handle being called in
assembly.

Since no one is including linux/jump_label.h in assembly yet, nothing
should break. We could however add __ASSEMBLY__ protection to all the
asm/jump_label.h files. Patches on the way.

Anton

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