[PATCH -next v19 23/24] riscv: Enable Vector code to be built

[Andy Chiu]

From: Guo Ren <guoren at linux.alibaba.com>

This patch adds a config which enables vector feature from the kernel
space.

Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
Co-developed-by: Greentime Hu <greentime.hu at sifive.com>
Signed-off-by: Greentime Hu <greentime.hu at sifive.com>
Suggested-by: Vineet Gupta <vineetg at rivosinc.com>
Suggested-by: Atish Patra <atishp at atishpatra.org>
Co-developed-by: Andy Chiu <andy.chiu at sifive.com>
Signed-off-by: Andy Chiu <andy.chiu at sifive.com>
---
Changelog V19:
 - Add RISCV_V_DISABLE to set compile-time default.

 arch/riscv/Kconfig  | 31 +++++++++++++++++++++++++++++++
 arch/riscv/Makefile |  6 +++++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 1019b519d590..fa256f2e23c1 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -466,6 +466,37 @@ config RISCV_ISA_SVPBMT
 
 	   If you don't know what to do here, say Y.
 
+config TOOLCHAIN_HAS_V
+	bool
+	default y
+	depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64iv)
+	depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32iv)
+	depends on LLD_VERSION >= 140000 || LD_VERSION >= 23800
+	depends on AS_HAS_OPTION_ARCH
+
+config RISCV_ISA_V
+	bool "VECTOR extension support"
+	depends on TOOLCHAIN_HAS_V
+	depends on FPU
+	select DYNAMIC_SIGFRAME
+	default y
+	help
+	  Say N here if you want to disable all vector related procedure
+	  in the kernel.
+
+	  If you don't know what to do here, say Y.
+
+config RISCV_V_DISABLE
+	bool "Disable userspace Vector by default"
+	depends on RISCV_ISA_V
+	default n
+	help
+	  Say Y here if you want to disable default enablement state of Vector
+	  in u-mode. This way userspace has to make explicit prctl() call to
+	  enable Vector, or enable it via sysctl interface.
+
+	  If you don't know what to do here, say N.
+
 config TOOLCHAIN_HAS_ZBB
 	bool
 	default y
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 0fb256bf8270..6ec6d52a4180 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -60,6 +60,7 @@ riscv-march-$(CONFIG_ARCH_RV32I)	:= rv32ima
 riscv-march-$(CONFIG_ARCH_RV64I)	:= rv64ima
 riscv-march-$(CONFIG_FPU)		:= $(riscv-march-y)fd
 riscv-march-$(CONFIG_RISCV_ISA_C)	:= $(riscv-march-y)c
+riscv-march-$(CONFIG_RISCV_ISA_V)	:= $(riscv-march-y)v
 
 ifdef CONFIG_TOOLCHAIN_NEEDS_OLD_ISA_SPEC
 KBUILD_CFLAGS += -Wa,-misa-spec=2.2
@@ -71,7 +72,10 @@ endif
 # Check if the toolchain supports Zihintpause extension
 riscv-march-$(CONFIG_TOOLCHAIN_HAS_ZIHINTPAUSE) := $(riscv-march-y)_zihintpause
 
-KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
+# Remove F,D,V from isa string for all. Keep extensions between "fd" and "v" by
+# matching non-v and non-multi-letter extensions out with the filter ([^v_]*)
+KBUILD_CFLAGS += -march=$(shell echo $(riscv-march-y) | sed -E 's/(rv32ima|rv64ima)fd([^v_]*)v?/\1\2/')
+
 KBUILD_AFLAGS += -march=$(riscv-march-y)
 
 KBUILD_CFLAGS += -mno-save-restore
-- 
2.17.1