Hi Will,
	Thanks for review.
On 12/13/2013 11:41 PM, Will Deacon wrote:

Hi Jiang Liu,

Thanks for the updated patches! I still have some small comments, but I
don't think they will cause you much work. See inline.

On Tue, Dec 10, 2013 at 04:03:52PM +0000, Jiang Liu wrote:

quoted

Optimize jump label implementation for ARM64 by dynamically patching
kernel text.

Signed-off-by: Jiang Liu <redacted>

...

quoted

+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef _ASM_ARM64_JUMP_LABEL_H
+#define _ASM_ARM64_JUMP_LABEL_H

Just use __ASM_JUMP_LABEL_H to keep consistent with out other headers.

Sure, will make this change.

quoted

+#include <linux/types.h>
+
+#ifdef __KERNEL__
+
+#define JUMP_LABEL_NOP_SIZE 4

This is the same as AARCH64_INSN_SIZE; just use the latter.

Yes, it's the same as AARCH64_INSN_SIZE but JUMP_LABEL_NOP_SIZE is
needed by the jump label core. So I directly define JUMP_LABEL_NOP_SIZE
as 4 instead of AARCH64_INSN_SIZE to avoid pulling asm/insn.h into
asm/jump_label.h.

Thanks!
Gerry

quoted

+
+static __always_inline bool arch_static_branch(struct static_key *key)
+{
+	asm goto("1: nop\n\t"
+		 ".pushsection __jump_table,  \"aw\"\n\t"
+		 ".align 3\n\t"
+		 ".quad 1b, %l[l_yes], %c0\n\t"
+		 ".popsection\n\t"
+		 :  :  "i"(key) :  : l_yes);
+
+	return false;
+l_yes:
+	return true;
+}
+
+#endif /* __KERNEL__ */
+
+typedef u64 jump_label_t;
+
+struct jump_entry {
+	jump_label_t code;
+	jump_label_t target;
+	jump_label_t key;
+};
+
+#endif	/* _ASM_ARM64_JUMP_LABEL_H */

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index cd95a25..e155d56 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile

@@ -18,6 +18,7 @@ arm64-obj-$(CONFIG_SMP)			+= smp.o smp_spin_table.o
 arm64-obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o
 arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)+= hw_breakpoint.o
 arm64-obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
+arm64-obj-$(CONFIG_JUMP_LABEL)		+= jump_label.o
 
 obj-y					+= $(arm64-obj-y) vdso/
 obj-m					+= $(arm64-obj-m)

diff --git a/arch/arm64/kernel/jump_label.c b/arch/arm64/kernel/jump_label.c
new file mode 100644
index 0000000..b13ef62
--- /dev/null
+++ b/arch/arm64/kernel/jump_label.c

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2013 Huawei Ltd.
+ * Author: Jiang Liu <liuj97@gmail.com>
+ *
+ * Based on arch/arm/kernel/jump_label.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/kernel.h>
+#include <linux/jump_label.h>
+#include <asm/jump_label.h>
+#include <asm/insn.h>
+
+#ifdef HAVE_JUMP_LABEL

Slightly worrying... this should be CONFIG_HAVE_JUMP_LABEL, right? How did
you manage to test this code?

Will