1 files changed, 147 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
new file mode 100644
index 000000000000..347805446151
--- /dev/null
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -0,0 +1,147 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2022-2024 Rivos, Inc
+ */
+
+#ifndef _ASM_CPUFEATURE_H
+#define _ASM_CPUFEATURE_H
+
+#include <linux/bitmap.h>
+#include <linux/jump_label.h>
+#include <asm/hwcap.h>
+#include <asm/alternative-macros.h>
+#include <asm/errno.h>
+
+/*
+ * These are probed via a device_initcall(), via either the SBI or directly
+ * from the corresponding CSRs.
+ */
+struct riscv_cpuinfo {
+	unsigned long mvendorid;
+	unsigned long marchid;
+	unsigned long mimpid;
+};
+
+struct riscv_isainfo {
+	DECLARE_BITMAP(isa, RISCV_ISA_EXT_MAX);
+};
+
+DECLARE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo);
+
+/* Per-cpu ISA extensions. */
+extern struct riscv_isainfo hart_isa[NR_CPUS];
+
+void riscv_user_isa_enable(void);
+
+#if defined(CONFIG_RISCV_MISALIGNED)
+bool check_unaligned_access_emulated_all_cpus(void);
+void unaligned_emulation_finish(void);
+bool unaligned_ctl_available(void);
+DECLARE_PER_CPU(long, misaligned_access_speed);
+#else
+static inline bool unaligned_ctl_available(void)
+{
+	return false;
+}
+#endif
+
+#if defined(CONFIG_RISCV_PROBE_UNALIGNED_ACCESS)
+DECLARE_STATIC_KEY_FALSE(fast_unaligned_access_speed_key);
+
+static __always_inline bool has_fast_unaligned_accesses(void)
+{
+	return static_branch_likely(&fast_unaligned_access_speed_key);
+}
+#else
+static __always_inline bool has_fast_unaligned_accesses(void)
+{
+	if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
+		return true;
+	else
+		return false;
+}
+#endif
+
+unsigned long riscv_get_elf_hwcap(void);
+
+struct riscv_isa_ext_data {
+	const unsigned int id;
+	const char *name;
+	const char *property;
+	const unsigned int *subset_ext_ids;
+	const unsigned int subset_ext_size;
+};
+
+extern const struct riscv_isa_ext_data riscv_isa_ext[];
+extern const size_t riscv_isa_ext_count;
+extern bool riscv_isa_fallback;
+
+unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap);
+
+bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, unsigned int bit);
+#define riscv_isa_extension_available(isa_bitmap, ext)	\
+	__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_##ext)
+
+static __always_inline bool
+riscv_has_extension_likely(const unsigned long ext)
+{
+	compiletime_assert(ext < RISCV_ISA_EXT_MAX,
+			   "ext must be < RISCV_ISA_EXT_MAX");
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE)) {
+		asm goto(
+		ALTERNATIVE("j	%l[l_no]", "nop", 0, %[ext], 1)
+		:
+		: [ext] "i" (ext)
+		:
+		: l_no);
+	} else {
+		if (!__riscv_isa_extension_available(NULL, ext))
+			goto l_no;
+	}
+
+	return true;
+l_no:
+	return false;
+}
+
+static __always_inline bool
+riscv_has_extension_unlikely(const unsigned long ext)
+{
+	compiletime_assert(ext < RISCV_ISA_EXT_MAX,
+			   "ext must be < RISCV_ISA_EXT_MAX");
+
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE)) {
+		asm goto(
+		ALTERNATIVE("nop", "j	%l[l_yes]", 0, %[ext], 1)
+		:
+		: [ext] "i" (ext)
+		:
+		: l_yes);
+	} else {
+		if (__riscv_isa_extension_available(NULL, ext))
+			goto l_yes;
+	}
+
+	return false;
+l_yes:
+	return true;
+}
+
+static __always_inline bool riscv_cpu_has_extension_likely(int cpu, const unsigned long ext)
+{
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) && riscv_has_extension_likely(ext))
+		return true;
+
+	return __riscv_isa_extension_available(hart_isa[cpu].isa, ext);
+}
+
+static __always_inline bool riscv_cpu_has_extension_unlikely(int cpu, const unsigned long ext)
+{
+	if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) && riscv_has_extension_unlikely(ext))
+		return true;
+
+	return __riscv_isa_extension_available(hart_isa[cpu].isa, ext);
+}
+
+#endif