[PATCH 5/6] arm64/asm: introduce lsui.h

[Yeoreum Yun]

This patch introduces lsui.h header file for applying runtime patch
to use load/store unprevileged instructions when cpu supports
FEAT_LSUI otherwise uses method implemented via ll/sc way with
clearing PSTATE.PAN bit

Signed-off-by: Yeoreum Yun <yeoreum.yun at arm.com>
---
 arch/arm64/include/asm/lsui.h | 37 +++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 arch/arm64/include/asm/lsui.h

diff --git a/arch/arm64/include/asm/lsui.h b/arch/arm64/include/asm/lsui.h
new file mode 100644
index 000000000000..39bf232f3eb7
--- /dev/null
+++ b/arch/arm64/include/asm/lsui.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2025 Arm Ltd.
+ */
+#ifndef __ASM_LSUI_H
+#define __ASM_LSUI_H
+
+#define LL_SC_MAX_LOOPS	128 /* What's the largest number you can think of? */
+
+#include <asm/futex_ll_sc_u.h>
+
+#ifdef CONFIG_AS_HAS_LSUI
+
+#define __LSUI_PREAMBLE	".arch_extension lsui\n"
+
+#include <linux/compiler_types.h>
+#include <linux/export.h>
+#include <linux/stringify.h>
+#include <asm/alternative.h>
+#include <asm/alternative-macros.h>
+#include <asm/cpucaps.h>
+
+#include <asm/futex_lsui.h>
+
+#define __lsui_ll_sc_u_body(op, ...)					\
+({									\
+	alternative_has_cap_likely(ARM64_HAS_LSUI) ?		\
+		__lsui_##op(__VA_ARGS__) :				\
+		__ll_sc_u_##op(__VA_ARGS__);				\
+})
+
+#else	/* CONFIG_AS_HAS_LSUI */
+
+#define __lsui_ll_sc_u_body(op, ...)		__ll_sc_u_##op(__VA_ARGS__)
+
+#endif	/* CONFIG_AS_HAS_LSUI */
+#endif	/* __ASM_LSUI_H */
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}