1 files changed, 0 insertions, 176 deletions
diff --git a/target/linux/generic/backport-5.4/041-v5.5-arm64-Implement-optimised-checksum-routine.patch b/target/linux/generic/backport-5.4/041-v5.5-arm64-Implement-optimised-checksum-routine.patch
deleted file mode 100644
index 00ec7d0207..0000000000
--- a/target/linux/generic/backport-5.4/041-v5.5-arm64-Implement-optimised-checksum-routine.patch
+++ /dev/null
@@ -1,176 +0,0 @@
-From: Robin Murphy <robin.murphy@arm.com>
-Date: Wed, 15 Jan 2020 16:42:39 +0000
-Subject: [PATCH] arm64: Implement optimised checksum routine
-
-Apparently there exist certain workloads which rely heavily on software
-checksumming, for which the generic do_csum() implementation becomes a
-significant bottleneck. Therefore let's give arm64 its own optimised
-version - for ease of maintenance this foregoes assembly or intrisics,
-and is thus not actually arm64-specific, but does rely heavily on C
-idioms that translate well to the A64 ISA and the typical load/store
-capabilities of most ARMv8 CPU cores.
-
-The resulting increase in checksum throughput scales nicely with buffer
-size, tending towards 4x for a small in-order core (Cortex-A53), and up
-to 6x or more for an aggressive big core (Ampere eMAG).
-
-Reported-by: Lingyan Huang <huanglingyan2@huawei.com>
-Tested-by: Lingyan Huang <huanglingyan2@huawei.com>
-Signed-off-by: Robin Murphy <robin.murphy@arm.com>
-Signed-off-by: Will Deacon <will@kernel.org>
----
- create mode 100644 arch/arm64/lib/csum.c
-
---- a/arch/arm64/include/asm/checksum.h
-+++ b/arch/arm64/include/asm/checksum.h
-@@ -36,6 +36,9 @@ static inline __sum16 ip_fast_csum(const
- }
- #define ip_fast_csum ip_fast_csum
- 
-+extern unsigned int do_csum(const unsigned char *buff, int len);
-+#define do_csum do_csum
-+
- #include <asm-generic/checksum.h>
- 
- #endif	/* __ASM_CHECKSUM_H */
---- a/arch/arm64/lib/Makefile
-+++ b/arch/arm64/lib/Makefile
-@@ -1,9 +1,9 @@
- # SPDX-License-Identifier: GPL-2.0
- lib-y		:= 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	\
--		   strchr.o strrchr.o tishift.o
-+		   clear_page.o csum.o memchr.o memcpy.o memmove.o	\
-+		   memset.o memcmp.o strcmp.o strncmp.o strlen.o	\
-+		   strnlen.o strchr.o strrchr.o tishift.o
- 
- ifeq ($(CONFIG_KERNEL_MODE_NEON), y)
- obj-$(CONFIG_XOR_BLOCKS)	+= xor-neon.o
---- /dev/null
-+++ b/arch/arm64/lib/csum.c
-@@ -0,0 +1,123 @@
-+// SPDX-License-Identifier: GPL-2.0-only
-+// Copyright (C) 2019-2020 Arm Ltd.
-+
-+#include <linux/compiler.h>
-+#include <linux/kasan-checks.h>
-+#include <linux/kernel.h>
-+
-+#include <net/checksum.h>
-+
-+/* Looks dumb, but generates nice-ish code */
-+static u64 accumulate(u64 sum, u64 data)
-+{
-+	__uint128_t tmp = (__uint128_t)sum + data;
-+	return tmp + (tmp >> 64);
-+}
-+
-+unsigned int do_csum(const unsigned char *buff, int len)
-+{
-+	unsigned int offset, shift, sum;
-+	const u64 *ptr;
-+	u64 data, sum64 = 0;
-+
-+	offset = (unsigned long)buff & 7;
-+	/*
-+	 * This is to all intents and purposes safe, since rounding down cannot
-+	 * result in a different page or cache line being accessed, and @buff
-+	 * should absolutely not be pointing to anything read-sensitive. We do,
-+	 * however, have to be careful not to piss off KASAN, which means using
-+	 * unchecked reads to accommodate the head and tail, for which we'll
-+	 * compensate with an explicit check up-front.
-+	 */
-+	kasan_check_read(buff, len);
-+	ptr = (u64 *)(buff - offset);
-+	len = len + offset - 8;
-+
-+	/*
-+	 * Head: zero out any excess leading bytes. Shifting back by the same
-+	 * amount should be at least as fast as any other way of handling the
-+	 * odd/even alignment, and means we can ignore it until the very end.
-+	 */
-+	shift = offset * 8;
-+	data = READ_ONCE_NOCHECK(*ptr++);
-+#ifdef __LITTLE_ENDIAN
-+	data = (data >> shift) << shift;
-+#else
-+	data = (data << shift) >> shift;
-+#endif
-+
-+	/*
-+	 * Body: straightforward aligned loads from here on (the paired loads
-+	 * underlying the quadword type still only need dword alignment). The
-+	 * main loop strictly excludes the tail, so the second loop will always
-+	 * run at least once.
-+	 */
-+	while (unlikely(len > 64)) {
-+		__uint128_t tmp1, tmp2, tmp3, tmp4;
-+
-+		tmp1 = READ_ONCE_NOCHECK(*(__uint128_t *)ptr);
-+		tmp2 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 2));
-+		tmp3 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 4));
-+		tmp4 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 6));
-+
-+		len -= 64;
-+		ptr += 8;
-+
-+		/* This is the "don't dump the carry flag into a GPR" idiom */
-+		tmp1 += (tmp1 >> 64) | (tmp1 << 64);
-+		tmp2 += (tmp2 >> 64) | (tmp2 << 64);
-+		tmp3 += (tmp3 >> 64) | (tmp3 << 64);
-+		tmp4 += (tmp4 >> 64) | (tmp4 << 64);
-+		tmp1 = ((tmp1 >> 64) << 64) | (tmp2 >> 64);
-+		tmp1 += (tmp1 >> 64) | (tmp1 << 64);
-+		tmp3 = ((tmp3 >> 64) << 64) | (tmp4 >> 64);
-+		tmp3 += (tmp3 >> 64) | (tmp3 << 64);
-+		tmp1 = ((tmp1 >> 64) << 64) | (tmp3 >> 64);
-+		tmp1 += (tmp1 >> 64) | (tmp1 << 64);
-+		tmp1 = ((tmp1 >> 64) << 64) | sum64;
-+		tmp1 += (tmp1 >> 64) | (tmp1 << 64);
-+		sum64 = tmp1 >> 64;
-+	}
-+	while (len > 8) {
-+		__uint128_t tmp;
-+
-+		sum64 = accumulate(sum64, data);
-+		tmp = READ_ONCE_NOCHECK(*(__uint128_t *)ptr);
-+
-+		len -= 16;
-+		ptr += 2;
-+
-+#ifdef __LITTLE_ENDIAN
-+		data = tmp >> 64;
-+		sum64 = accumulate(sum64, tmp);
-+#else
-+		data = tmp;
-+		sum64 = accumulate(sum64, tmp >> 64);
-+#endif
-+	}
-+	if (len > 0) {
-+		sum64 = accumulate(sum64, data);
-+		data = READ_ONCE_NOCHECK(*ptr);
-+		len -= 8;
-+	}
-+	/*
-+	 * Tail: zero any over-read bytes similarly to the head, again
-+	 * preserving odd/even alignment.
-+	 */
-+	shift = len * -8;
-+#ifdef __LITTLE_ENDIAN
-+	data = (data << shift) >> shift;
-+#else
-+	data = (data >> shift) << shift;
-+#endif
-+	sum64 = accumulate(sum64, data);
-+
-+	/* Finally, folding */
-+	sum64 += (sum64 >> 32) | (sum64 << 32);
-+	sum = sum64 >> 32;
-+	sum += (sum >> 16) | (sum << 16);
-+	if (offset & 1)
-+		return (u16)swab32(sum);
-+
-+	return sum >> 16;
-+}