1 files changed, 70 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/alternative.h b/arch/riscv/include/asm/alternative.h
new file mode 100644
index 000000000000..3c2b59b25017
--- /dev/null
+++ b/arch/riscv/include/asm/alternative.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2021 Sifive.
+ */
+
+#ifndef __ASM_ALTERNATIVE_H
+#define __ASM_ALTERNATIVE_H
+
+#include <asm/alternative-macros.h>
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_RISCV_ALTERNATIVE
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/stddef.h>
+#include <asm/hwcap.h>
+
+#define PATCH_ID_CPUFEATURE_ID(p)		lower_16_bits(p)
+#define PATCH_ID_CPUFEATURE_VALUE(p)		upper_16_bits(p)
+
+#define RISCV_ALTERNATIVES_BOOT		0 /* alternatives applied during regular boot */
+#define RISCV_ALTERNATIVES_MODULE	1 /* alternatives applied during module-init */
+#define RISCV_ALTERNATIVES_EARLY_BOOT	2 /* alternatives applied before mmu start */
+
+/* add the relative offset to the address of the offset to get the absolute address */
+#define __ALT_PTR(a, f)			((void *)&(a)->f + (a)->f)
+#define ALT_OLD_PTR(a)			__ALT_PTR(a, old_offset)
+#define ALT_ALT_PTR(a)			__ALT_PTR(a, alt_offset)
+
+void __init apply_boot_alternatives(void);
+void __init apply_early_boot_alternatives(void);
+void apply_module_alternatives(void *start, size_t length);
+
+void riscv_alternative_fix_offsets(void *alt_ptr, unsigned int len,
+				   int patch_offset);
+
+struct alt_entry {
+	s32 old_offset;		/* offset relative to original instruction or data  */
+	s32 alt_offset;		/* offset relative to replacement instruction or data */
+	u16 vendor_id;		/* CPU vendor ID */
+	u16 alt_len;		/* The replacement size */
+	u32 patch_id;		/* The patch ID (erratum ID or cpufeature ID) */
+};
+
+void andes_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+			     unsigned long archid, unsigned long impid,
+			     unsigned int stage);
+void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+			      unsigned long archid, unsigned long impid,
+			      unsigned int stage);
+void thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+			     unsigned long archid, unsigned long impid,
+			     unsigned int stage);
+
+void riscv_cpufeature_patch_func(struct alt_entry *begin, struct alt_entry *end,
+				 unsigned int stage);
+
+#else /* CONFIG_RISCV_ALTERNATIVE */
+
+static inline void apply_boot_alternatives(void) { }
+static inline void apply_early_boot_alternatives(void) { }
+static inline void apply_module_alternatives(void *start, size_t length) { }
+
+#endif /* CONFIG_RISCV_ALTERNATIVE */
+
+#endif
+#endif