[PATCH v2 2/2] riscv: Disable misaligned access probe when CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS

Elliot Berman quic_eberman at quicinc.com
Thu Feb 1 20:31:10 PST 2024


Hi Charlie,

On Thu, Feb 01, 2024 at 03:30:46PM -0800, Charlie Jenkins wrote:
> When CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is selected, the cpus can be
> set to have fast misaligned access without needing to probe.
> 
> Signed-off-by: Charlie Jenkins <charlie at rivosinc.com>
> ---
>  arch/riscv/Kconfig                               |   1 +
>  arch/riscv/include/asm/cpufeature.h              |   7 +
>  arch/riscv/include/asm/misaligned_access_speed.h |  29 +++
>  arch/riscv/kernel/Makefile                       |   3 +
>  arch/riscv/kernel/cpufeature.c                   | 255 ----------------------
>  arch/riscv/kernel/misaligned_access_speed.c      | 265 +++++++++++++++++++++++
>  arch/riscv/kernel/sys_hwprobe.c                  |   4 +
>  7 files changed, 309 insertions(+), 255 deletions(-)
> 
> diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
> index f71910718053..8be7f17da9ab 100644
> --- a/arch/riscv/kernel/Makefile
> +++ b/arch/riscv/kernel/Makefile
> @@ -62,6 +62,9 @@ obj-y	+= tests/
>  obj-$(CONFIG_MMU) += vdso.o vdso/
>  
>  obj-$(CONFIG_RISCV_MISALIGNED)	+= traps_misaligned.o
> +ifneq ($(RISCV_EFFICIENT_UNALIGNED_ACCESS), y)

Should this be CONFIG_RISCV_EFFICIENT_UNALIGNED_ACCESS ?

> +obj-y	+= misaligned_access_speed.o
> +endif
>  obj-$(CONFIG_FPU)		+= fpu.o
>  obj-$(CONFIG_RISCV_ISA_V)	+= vector.o
>  obj-$(CONFIG_RISCV_ISA_V)	+= kernel_mode_vector.o



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