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Subject[PATCH] riscv: avoid enabling vectorized code generation
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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@google.com>
---
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
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