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-rw-r--r--kernel/arch/arm64/include/asm/alternative-asm.h29
1 files changed, 29 insertions, 0 deletions
diff --git a/kernel/arch/arm64/include/asm/alternative-asm.h b/kernel/arch/arm64/include/asm/alternative-asm.h
new file mode 100644
index 000000000..919a67855
--- /dev/null
+++ b/kernel/arch/arm64/include/asm/alternative-asm.h
@@ -0,0 +1,29 @@
+#ifndef __ASM_ALTERNATIVE_ASM_H
+#define __ASM_ALTERNATIVE_ASM_H
+
+#ifdef __ASSEMBLY__
+
+.macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len
+ .word \orig_offset - .
+ .word \alt_offset - .
+ .hword \feature
+ .byte \orig_len
+ .byte \alt_len
+.endm
+
+.macro alternative_insn insn1 insn2 cap
+661: \insn1
+662: .pushsection .altinstructions, "a"
+ altinstruction_entry 661b, 663f, \cap, 662b-661b, 664f-663f
+ .popsection
+ .pushsection .altinstr_replacement, "ax"
+663: \insn2
+664: .popsection
+ .if ((664b-663b) != (662b-661b))
+ .error "Alternatives instruction length mismatch"
+ .endif
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_ALTERNATIVE_ASM_H */