> From: Wang, Yalin
> Subject: [RFC V6 2/3] add CONFIG_HAVE_ARCH_BITREVERSE to support rbit
> instruction
>
> This patch add bitrev.h file to support rbit instruction, so that we can do
> bitrev operation by hardware.
> Signed-off-by: Yalin Wang <yalin.wang@xxxxxxxxxxxxxx>
> ---
> arch/arm/Kconfig | 1 +
> arch/arm/include/asm/bitrev.h | 21 +++++++++++++++++++++
> 2 files changed, 22 insertions(+)
> create mode 100644 arch/arm/include/asm/bitrev.h
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 89c4b5c..be92b3b
> 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -28,6 +28,7 @@ config ARM
> select HANDLE_DOMAIN_IRQ
> select HARDIRQS_SW_RESEND
> select HAVE_ARCH_AUDITSYSCALL if (AEABI && !OABI_COMPAT)
> + select HAVE_ARCH_BITREVERSE if (CPU_V7M || CPU_V7)
> select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
> select HAVE_ARCH_KGDB
> select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT) diff --git
> a/arch/arm/include/asm/bitrev.h b/arch/arm/include/asm/bitrev.h new file
> mode 100644 index 0000000..e9b2571
> --- /dev/null
> +++ b/arch/arm/include/asm/bitrev.h
> @@ -0,0 +1,21 @@
> +#ifndef __ASM_ARM_BITREV_H
> +#define __ASM_ARM_BITREV_H
> +
> +static __always_inline __attribute_const__ u32 __arch_bitrev32(u32 x) {
> + __asm__ ("rbit %0, %1" : "=r" (x) : "r" (x));
> + return x;
> +}
> +
> +static __always_inline __attribute_const__ u16 __arch_bitrev16(u16 x) {
> + return __arch_bitrev32((u32)x) >> 16;
> +}
> +
> +static __always_inline __attribute_const__ u8 __arch_bitrev8(u8 x) {
> + return __arch_bitrev32((u32)x) >> 24;
> +}
> +
> +#endif
> +
> --
> 2.1.1
Wrong title, please ignore this one ,
I have resend another [RFC V6 2/3] .
Thanks
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