[PATCH] riscv: avoid enabling vectorized code generation

[Saleem Abdulrasool]

The compiler is free to generate vectorized operations for zero'ing
memory.  The kernel does not use the vector unit on RISCV, similar to
architectures such as x86 where we use `-mno-mmx` et al to prevent the
implicit vectorization.  Perform a similar check for
`-mno-implicit-float` to avoid this on RISC-V targets.

Signed-off-by: Saleem Abdulrasool <abdulras@xxxxxxxxxx>
---
 arch/riscv/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 0d13b597cb55..68433476a96e 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -89,6 +89,10 @@ KBUILD_AFLAGS_MODULE += $(call as-option,-Wa$(comma)-mno-relax)
 # architectures.  It's faster to have GCC emit only aligned accesses.
 KBUILD_CFLAGS += $(call cc-option,-mstrict-align)
 
+# Ensure that we do not vectorize the kernel code when the `v` extension is
+# enabled.  This mirrors the `-mno-mmx` et al on x86.
+KBUILD_CFLAGS += $(call cc-option,-mno-implicit-float)
+
 ifeq ($(CONFIG_STACKPROTECTOR_PER_TASK),y)
 prepare: stack_protector_prepare
 stack_protector_prepare: prepare0
-- 
2.39.0.314.g84b9a713c41-goog