Messages in this thread Patch in this message | | | From | huhai <> | Subject | [PATCH v2] arm64/lib: add accelerated do_csum for arm64 | Date | Fri, 4 Jan 2019 11:39:49 +0800 |
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do_csum() in lib/checksum.c is too slow in ARM64, and we can use assembly and algorithm to accelerate it.
V2: Fix compile warning reported by kbuild test robot <lkp@intel.com>
Signed-off-by: huhai <huhai@kylinos.cn> --- arch/arm64/include/asm/checksum.h | 3 + arch/arm64/lib/Makefile | 2 +- arch/arm64/lib/checksum.c | 145 ++++++++++++++++++++++++++++++ 3 files changed, 149 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/lib/checksum.c
diff --git a/arch/arm64/include/asm/checksum.h b/arch/arm64/include/asm/checksum.h index 0b6f5a7d4027..0d7b80fb300e 100644 --- a/arch/arm64/include/asm/checksum.h +++ b/arch/arm64/include/asm/checksum.h @@ -26,6 +26,9 @@ static inline __sum16 csum_fold(__wsum csum) } #define csum_fold csum_fold +#define do_csum do_csum +unsigned int do_csum(const unsigned char *buff, unsigned int len); + static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) { __uint128_t tmp; diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile index 69ff9887f724..4134730a121b 100644 --- a/arch/arm64/lib/Makefile +++ b/arch/arm64/lib/Makefile @@ -1,5 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 -lib-y := clear_user.o delay.o copy_from_user.o \ +lib-y := checksum.o clear_user.o delay.o copy_from_user.o \ copy_to_user.o copy_in_user.o copy_page.o \ clear_page.o memchr.o memcpy.o memmove.o memset.o \ memcmp.o strcmp.o strncmp.o strlen.o strnlen.o \ diff --git a/arch/arm64/lib/checksum.c b/arch/arm64/lib/checksum.c new file mode 100644 index 000000000000..5df8c6f9a8ac --- /dev/null +++ b/arch/arm64/lib/checksum.c @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Authors: huhai <huhai@kylinos.cn> + * Copyright (C) 2019,Tianjin KYLIN Information Technology Co., Ltd. + * + * This file contains network checksum routines that are better done + * in an architecture-specific manner due to speed. + * + * Acknowledgements: + * This file is based on arch/x86/lib/csum-partial_64.c and + * arch/alpha/lib/checksum.c, which was written by Thomas Gleixner + * and Rick Gorton respectively. + */ + +#include <linux/compiler.h> +#include <linux/module.h> +#include <asm/checksum.h> + +static inline unsigned short from64to16(unsigned long x) +{ + /* + * Using extract instructions is a bit more efficient + * than the original shift/bitmask version. + */ + union { + unsigned long ul; + unsigned int ui[2]; + unsigned short us[4]; + } in_v, tmp_v, out_v; + + in_v.ul = x; + tmp_v.ul = (unsigned long) in_v.ui[0] + (unsigned long) in_v.ui[1]; + + /* + * Since the bits of tmp_v.sh[3] are going to always be zero, + * we don't have to bother to add that in. + */ + out_v.ul = (unsigned long) tmp_v.us[0] + (unsigned long) tmp_v.us[1] + + (unsigned long) tmp_v.us[2]; + + /* Similarly, out_v.us[2] is always zero for the final add. */ + return out_v.us[0] + out_v.us[1]; +} + +/* + * Do a 64-bit checksum on an arbitrary memory area. + * Returns a 16bit checksum. + */ +unsigned int do_csum(const unsigned char *buff, unsigned len) +{ + unsigned odd, count; + unsigned long result = 0; + + if (unlikely(len == 0)) + return result; + odd = 1 & (unsigned long) buff; + if (odd) { + result = *buff << 8; + len--; + buff++; + } + count = len >> 1; /* nr of 16-bit words.. */ + if (count) { + if (2 & (unsigned long) buff) { + result += *(unsigned short *)buff; + count--; + len -= 2; + buff += 2; + } + count >>= 1; /* nr of 32-bit words.. */ + if (count) { + unsigned long zero = 0; + unsigned count64; + + if (4 & (unsigned long) buff) { + result += *(unsigned int *) buff; + count--; + len -= 4; + buff += 4; + } + count >>= 1; /* nr of 64-bit words.. */ + + /* main loop using 64byte blocks */ + count64 = count >> 3; + while (count64) { + __asm__ __volatile__( + "ldr x3, [%x1, #0]\n" + "adds %x0, %x0, x3\n" + "ldr x3, [%x1, #8]\n" + "adcs %x0, %x0, x3\n" + "ldr x3, [%x1, #16]\n" + "adcs %x0, %x0, x3\n" + "ldr x3, [%x1, #24]\n" + "adcs %x0, %x0, x3\n" + "ldr x3, [%x1, #32]\n" + "adcs %x0, %x0, x3\n" + "ldr x3, [%x1, #40]\n" + "adcs %x0, %x0, x3\n" + "ldr x3, [%x1, #48]\n" + "adcs %x0, %x0, x3\n" + "ldr x3, [%x1, #56]\n" + "adcs %x0, %x0, x3\n" + "adcs %x0, %x0, %x2\n" + : "=r" (result) + : "r" (buff), "r" (zero), "0" (result) + : "cc", "memory", "x3"); + + buff += 64; + count64--; + } + + /* last up to 7 8byte blocks */ + count %= 8; + + while (count) { + __asm__ __volatile__( + "adds %x0, %x0, %x1\n" + "adcs %x0, %x0, %x2\n" + : "=r" (result) + : "r" (*(unsigned long *)buff), "r" (zero), "0" (result) + : "cc", "memory"); + --count; + buff += 8; + } + result = (result & 0xffffffff) + (result >> 32); + + if (len & 4) { + result += *(unsigned int *) buff; + buff += 4; + } + } + if (len & 2) { + result += *(unsigned short *) buff; + buff += 2; + } + } + if (len & 1) + result += *buff; + + result = from64to16(result); + if (odd) + result = ((result >> 8) & 0xff) | ((result & 0xff) << 8); + + return result; +} -- 2.17.0
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