[PATCH RFC] arm/arm64:add CONFIG_HAVE_ARCH_BITREVERSE to support rbit
From: Wang, Yalin <hidden>
Date: 2014-10-24 05:10:40
Also in:
linux-mm, lkml
Subsystem:
arm port, arm64 port (aarch64 architecture), bitops api, library code, the rest · Maintainers:
Russell King, Catalin Marinas, Will Deacon, Yury Norov, Andrew Morton, Linus Torvalds
this change add CONFIG_HAVE_ARCH_BITREVERSE config option, so that we can use arm/arm64 rbit instruction to do bitrev operation by hardware. Signed-off-by: Yalin Wang <redacted> --- arch/arm/Kconfig | 1 + arch/arm/include/asm/bitrev.h | 21 +++++++++++++++++++++ arch/arm64/Kconfig | 1 + arch/arm64/include/asm/bitrev.h | 21 +++++++++++++++++++++ include/linux/bitrev.h | 9 +++++++++ lib/Kconfig | 8 ++++++++ lib/bitrev.c | 2 ++ 7 files changed, 63 insertions(+) create mode 100644 arch/arm/include/asm/bitrev.h create mode 100644 arch/arm64/include/asm/bitrev.h
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 89c4b5c..426cbcc 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig@@ -16,6 +16,7 @@ config ARM select DCACHE_WORD_ACCESS if HAVE_EFFICIENT_UNALIGNED_ACCESS select GENERIC_ALLOCATOR select GENERIC_ATOMIC64 if (CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI) + select HAVE_ARCH_BITREVERSE if (CPU_V7M || CPU_V7) select GENERIC_CLOCKEVENTS_BROADCAST if SMP select GENERIC_IDLE_POLL_SETUP select GENERIC_IRQ_PROBE
diff --git a/arch/arm/include/asm/bitrev.h b/arch/arm/include/asm/bitrev.h
new file mode 100644
index 0000000..0df5866
--- /dev/null
+++ b/arch/arm/include/asm/bitrev.h@@ -0,0 +1,21 @@ +#ifndef __ASM_ARM_BITREV_H +#define __ASM_ARM_BITREV_H + +static inline __attribute_const__ u32 __arch_bitrev32(u32 x) +{ + __asm__ ("rbit %0, %1" : "=r" (x) : "r" (x)); + return x; +} + +static inline __attribute_const__ u16 __arch_bitrev16(u16 x) +{ + return __arch_bitrev32((u32)x) >> 16; +} + +static inline __attribute_const__ u8 __arch_bitrev8(u8 x) +{ + return __arch_bitrev32((u32)x) >> 24; +} + +#endif +
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index ac9afde..a2566d7 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig@@ -35,6 +35,7 @@ config ARM64 select HARDIRQS_SW_RESEND select HAVE_ARCH_AUDITSYSCALL select HAVE_ARCH_JUMP_LABEL + select HAVE_ARCH_BITREVERSE select HAVE_ARCH_KGDB select HAVE_ARCH_TRACEHOOK select HAVE_BPF_JIT
diff --git a/arch/arm64/include/asm/bitrev.h b/arch/arm64/include/asm/bitrev.h
new file mode 100644
index 0000000..5d24c11
--- /dev/null
+++ b/arch/arm64/include/asm/bitrev.h@@ -0,0 +1,21 @@ +#ifndef __ASM_ARM_BITREV_H +#define __ASM_ARM_BITREV_H + +static inline __attribute_const__ u32 __arch_bitrev32(u32 x) +{ + __asm__ ("rbit %w0, %w1" : "=r" (x) : "r" (x)); + return x; +} + +static inline __attribute_const__ u16 __arch_bitrev16(u16 x) +{ + return __arch_bitrev32((u32)x) >> 16; +} + +static inline __attribute_const__ u8 __arch_bitrev8(u8 x) +{ + return __arch_bitrev32((u32)x) >> 24; +} + +#endif +
diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
index 7ffe03f..ef5b2bb 100644
--- a/include/linux/bitrev.h
+++ b/include/linux/bitrev.h@@ -3,6 +3,14 @@ #include <linux/types.h> +#ifdef CONFIG_HAVE_ARCH_BITREVERSE +#include <asm/bitrev.h> + +#define bitrev32 __arch_bitrev32 +#define bitrev16 __arch_bitrev16 +#define bitrev8 __arch_bitrev8 + +#else extern u8 const byte_rev_table[256]; static inline u8 bitrev8(u8 byte)
@@ -13,4 +21,5 @@ static inline u8 bitrev8(u8 byte) extern u16 bitrev16(u16 in); extern u32 bitrev32(u32 in); +#endif /* CONFIG_HAVE_ARCH_BITREVERSE */ #endif /* _LINUX_BITREV_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index 54cf309..e0e0453 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig@@ -13,6 +13,14 @@ config RAID6_PQ config BITREVERSE tristate +config HAVE_ARCH_BITREVERSE + boolean + default n + help + This option provides an config for the architecture which have instruction + can do bitreverse operation, we use the hardware instruction if the architecture + have this capability. + config RATIONAL boolean
diff --git a/lib/bitrev.c b/lib/bitrev.c
index 3956203..93d637a 100644
--- a/lib/bitrev.c
+++ b/lib/bitrev.c@@ -1,3 +1,4 @@ +#ifndef CONFIG_HAVE_ARCH_BITREVERSE #include <linux/types.h> #include <linux/module.h> #include <linux/bitrev.h>
@@ -57,3 +58,4 @@ u32 bitrev32(u32 x) return (bitrev16(x & 0xffff) << 16) | bitrev16(x >> 16); } EXPORT_SYMBOL(bitrev32); +#endif /* CONFIG_HAVE_ARCH_BITREVERSE */
--
2.1.1