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authorJiang Liu <liuj97@gmail.com>2014-01-07 22:17:13 +0800
committerMark Brown <broonie@linaro.org>2014-05-20 13:02:05 +0100
commitd6e6ff5d209e801eea5e519596fa6de9b3145418 (patch)
treeafda3f1c53d09df5b171f036f7e7c386c54dbdde /arch/arm64/include/asm/jump_label.h
parent228d249ff91b4ed822a6e4f760c8b3e2de7c0668 (diff)
downloadlinux-linaro-stable-d6e6ff5d209e801eea5e519596fa6de9b3145418.tar.gz
arm64, jump label: optimize jump label implementationv3.10/topic/arm64-insn
Optimize jump label implementation for ARM64 by dynamically patching kernel text. Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> (cherry picked from commit 9732cafd9dc0206479be919baf0067239f0a63ca) Signed-off-by: Mark Brown <broonie@linaro.org> Conflicts: arch/arm64/kernel/Makefile
Diffstat (limited to 'arch/arm64/include/asm/jump_label.h')
-rw-r--r--arch/arm64/include/asm/jump_label.h52
1 files changed, 52 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/jump_label.h b/arch/arm64/include/asm/jump_label.h
new file mode 100644
index 000000000000..076a1c714049
--- /dev/null
+++ b/arch/arm64/include/asm/jump_label.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2013 Huawei Ltd.
+ * Author: Jiang Liu <liuj97@gmail.com>
+ *
+ * Based on arch/arm/include/asm/jump_label.h
+ *
+ * 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/>.
+ */
+#ifndef __ASM_JUMP_LABEL_H
+#define __ASM_JUMP_LABEL_H
+#include <linux/types.h>
+#include <asm/insn.h>
+
+#ifdef __KERNEL__
+
+#define JUMP_LABEL_NOP_SIZE AARCH64_INSN_SIZE
+
+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_JUMP_LABEL_H */