File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/arm64/include/asm/lse.h b/arch/arm64/include/asm/lse.h
new file mode 100644
index 0000000..3de42d6
--- /dev/null
+++ b/arch/arm64/include/asm/lse.h
@@ -0,0 +1,53 @@
+#ifndef __ASM_LSE_H
+#define __ASM_LSE_H
+
+#if defined(CONFIG_AS_LSE) && defined(CONFIG_ARM64_LSE_ATOMICS)
+
+#include <linux/stringify.h>
+#include <asm/alternative.h>
+#include <asm/cpufeature.h>
+
+#ifdef __ASSEMBLER__
+
+.arch_extension lse
+
+.macro alt_lse, llsc, lse
+ alternative_insn "\llsc", "\lse", ARM64_HAS_LSE_ATOMICS
+.endm
+
+#else /* __ASSEMBLER__ */
+
+__asm__(".arch_extension lse");
+
+/* Move the ll/sc atomics out-of-line */
+#define __LL_SC_INLINE
+#define __LL_SC_PREFIX(x) __ll_sc_##x
+#define __LL_SC_EXPORT(x) EXPORT_SYMBOL(__LL_SC_PREFIX(x))
+
+/* Macro for constructing calls to out-of-line ll/sc atomics */
+#define __LL_SC_CALL(op) "bl\t" __stringify(__LL_SC_PREFIX(op)) "\n"
+
+/* In-line patching at runtime */
+#define ARM64_LSE_ATOMIC_INSN(llsc, lse) \
+ ALTERNATIVE(llsc, lse, ARM64_HAS_LSE_ATOMICS)
+
+#endif /* __ASSEMBLER__ */
+#else /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
+
+#ifdef __ASSEMBLER__
+
+.macro alt_lse, llsc, lse
+ \llsc
+.endm
+
+#else /* __ASSEMBLER__ */
+
+#define __LL_SC_INLINE static inline
+#define __LL_SC_PREFIX(x) x
+#define __LL_SC_EXPORT(x)
+
+#define ARM64_LSE_ATOMIC_INSN(llsc, lse) llsc
+
+#endif /* __ASSEMBLER__ */
+#endif /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
+#endif /* __ASM_LSE_H */