riscv: Move cpufeature.h macros into their own header

asm/cmpxchg.h will soon need riscv_has_extension_unlikely() macros and
then needs to include asm/cpufeature.h which introduces a lot of header
circular dependencies.

So move the riscv_has_extension_XXX() macros into their own header which
prevents such circular dependencies by including a restricted number of
headers.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20241103145153.105097-2-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

1 files changed, 66 insertions, 0 deletions

diff --git a/arch/riscv/include/asm/cpufeature-macros.h b/arch/riscv/include/asm/cpufeature-macros.h
new file mode 100644
index 000000000000..a8103edbf51f
--- /dev/null
+++ b/arch/riscv/include/asm/cpufeature-macros.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2022-2024 Rivos, Inc
+ */
+
+#ifndef _ASM_CPUFEATURE_MACROS_H
+#define _ASM_CPUFEATURE_MACROS_H
+
+#include <asm/hwcap.h>
+#include <asm/alternative-macros.h>
+
+#define STANDARD_EXT		0
+
+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 vendor,
+							 const unsigned long ext)
+{
+	asm goto(ALTERNATIVE("j	%l[l_no]", "nop", %[vendor], %[ext], 1)
+	:
+	: [vendor] "i" (vendor), [ext] "i" (ext)
+	:
+	: l_no);
+
+	return true;
+l_no:
+	return false;
+}
+
+static __always_inline bool __riscv_has_extension_unlikely(const unsigned long vendor,
+							   const unsigned long ext)
+{
+	asm goto(ALTERNATIVE("nop", "j	%l[l_yes]", %[vendor], %[ext], 1)
+	:
+	: [vendor] "i" (vendor), [ext] "i" (ext)
+	:
+	: l_yes);
+
+	return false;
+l_yes:
+	return true;
+}
+
+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))
+		return __riscv_has_extension_unlikely(STANDARD_EXT, ext);
+
+	return __riscv_isa_extension_available(NULL, 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))
+		return __riscv_has_extension_likely(STANDARD_EXT, ext);
+
+	return __riscv_isa_extension_available(NULL, ext);
+}
+
+#endif /* _ASM_CPUFEATURE_MACROS_H */