[PATCH -next v17 02/20] riscv: Extending cpufeature.c to detect V-extension

Andy Chiu
2023-03-27T16:50:04Z

From: Guo Ren <ren_guo@c-sky.com>

Add V-extension into riscv_isa_ext_keys array and detect it with isa
string parsing.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Suggested-by: Vineet Gupta <vineetg@rivosinc.com>
Co-developed-by: Andy Chiu <andy.chiu@sifive.com>
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
arch/riscv/include/asm/hwcap.h | 1 +
arch/riscv/include/asm/vector.h | 26 ++++++++++++++++++++++++++
arch/riscv/include/uapi/asm/hwcap.h | 1 +
arch/riscv/kernel/cpufeature.c | 11 +++++++++++
4 files changed, 39 insertions(+)
create mode 100644 arch/riscv/include/asm/vector.h

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index bbde5aafa957..7df8db320934 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -22,6 +22,7 @@
#define RISCV_ISA_EXT_m ('m' - 'a')
#define RISCV_ISA_EXT_s ('s' - 'a')
#define RISCV_ISA_EXT_u ('u' - 'a')
+#define RISCV_ISA_EXT_v ('v' - 'a')

/*
* These macros represent the logical IDs of each multi-letter RISC-V ISA
diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h
new file mode 100644
index 000000000000..427a3b51df72
--- /dev/null
+++ b/arch/riscv/include/asm/vector.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2020 SiFive
+ */
+
+#ifndef __ASM_RISCV_VECTOR_H
+#define __ASM_RISCV_VECTOR_H
+
+#include <linux/types.h>
+
+#ifdef CONFIG_RISCV_ISA_V
+
+#include <asm/hwcap.h>
+
+static __always_inline bool has_vector(void)
+{
+ return riscv_has_extension_likely(RISCV_ISA_EXT_v);
+}
+
+#else /* ! CONFIG_RISCV_ISA_V */
+
+static __always_inline bool has_vector(void) { return false; }
+
+#endif /* CONFIG_RISCV_ISA_V */
+
+#endif /* ! __ASM_RISCV_VECTOR_H */
diff --git a/arch/riscv/include/uapi/asm/hwcap.h b/arch/riscv/include/uapi/asm/hwcap.h
index 46dc3f5ee99f..c52bb7bbbabe 100644
--- a/arch/riscv/include/uapi/asm/hwcap.h
+++ b/arch/riscv/include/uapi/asm/hwcap.h
@@ -21,5 +21,6 @@
#define COMPAT_HWCAP_ISA_F (1 << ('F' - 'A'))
#define COMPAT_HWCAP_ISA_D (1 << ('D' - 'A'))
#define COMPAT_HWCAP_ISA_C (1 << ('C' - 'A'))
+#define COMPAT_HWCAP_ISA_V (1 << ('V' - 'A'))

#endif /* _UAPI_ASM_RISCV_HWCAP_H */
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 00d7cd2c9043..923ca75f2192 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -103,6 +103,7 @@ void __init riscv_fill_hwcap(void)
isa2hwcap['f' - 'a'] = COMPAT_HWCAP_ISA_F;
isa2hwcap['d' - 'a'] = COMPAT_HWCAP_ISA_D;
isa2hwcap['c' - 'a'] = COMPAT_HWCAP_ISA_C;
+ isa2hwcap['v' - 'a'] = COMPAT_HWCAP_ISA_V;

elf_hwcap = 0;

@@ -261,6 +262,16 @@ void __init riscv_fill_hwcap(void)
elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
}

+ if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
+ /*
+ * ISA string in device tree might have 'v' flag, but
+ * CONFIG_RISCV_ISA_V is disabled in kernel.
+ * Clear V flag in elf_hwcap if CONFIG_RISCV_ISA_V is disabled.
+ */
+ if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
+ elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
+ }
+
memset(print_str, 0, sizeof(print_str));
for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
if (riscv_isa[0] & BIT_MASK(i))
--
2.17.1