git: ecbbe831445a - main - netinet: Deduplicate most in_cksum() implementations

From: Mark Johnston <markj_at_FreeBSD.org>
Date: Wed, 24 Nov 2021 18:39:36 UTC
The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=ecbbe831445a4b94279e5932828d60076e4ca444

commit ecbbe831445a4b94279e5932828d60076e4ca444
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2021-11-24 18:19:44 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2021-11-24 18:31:16 +0000

    netinet: Deduplicate most in_cksum() implementations
    
    in_cksum() and related routines are implemented separately for each
    platform, but only i386 and arm have optimized versions.  Other
    platforms' copies of in_cksum.c are identical except for style
    differences and support for big-endian CPUs.
    
    Deduplicate the implementations for the rest of the platforms.  This
    will make it easier to implement in_cksum() for unmapped mbufs.  On arm
    and i386, define HAVE_MD_IN_CKSUM to mean that the MI implementation is
    not to be compiled.
    
    No functional change intended.
    
    Reviewed by:    kp, glebius
    MFC after:      1 week
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D33095
---
 sys/amd64/amd64/in_cksum.c                       | 243 ----------------------
 sys/arm/arm/{in_cksum.c => in_cksum_machdep.c}   |   0
 sys/arm/include/in_cksum.h                       |   3 +
 sys/arm64/arm64/in_cksum.c                       | 241 ---------------------
 sys/conf/files                                   |   1 +
 sys/conf/files.amd64                             |   1 -
 sys/conf/files.arm                               |   2 +-
 sys/conf/files.arm64                             |   1 -
 sys/conf/files.i386                              |   2 +-
 sys/conf/files.mips                              |   1 -
 sys/conf/files.powerpc                           |   1 -
 sys/conf/files.riscv                             |   1 -
 sys/i386/i386/{in_cksum.c => in_cksum_machdep.c} |   0
 sys/i386/include/in_cksum.h                      |   3 +
 sys/{mips/mips => netinet}/in_cksum.c            |   7 +
 sys/powerpc/powerpc/in_cksum.c                   | 253 -----------------------
 sys/riscv/riscv/in_cksum.c                       | 243 ----------------------
 17 files changed, 16 insertions(+), 987 deletions(-)

diff --git a/sys/amd64/amd64/in_cksum.c b/sys/amd64/amd64/in_cksum.c
deleted file mode 100644
index 30e90f043cc3..000000000000
--- a/sys/amd64/amd64/in_cksum.c
+++ /dev/null
@@ -1,243 +0,0 @@
-/* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */
-
-/*-
- * SPDX-License-Identifier: BSD-4-Clause
- *
- * Copyright (c) 1988, 1992, 1993
- *	The Regents of the University of California.  All rights reserved.
- * Copyright (c) 1996
- *	Matt Thomas <matt@3am-software.com>
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *	This product includes software developed by the University of
- *	California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- *	@(#)in_cksum.c	8.1 (Berkeley) 6/10/93
- */
-
-#include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
-__FBSDID("$FreeBSD$");
-
-#include <sys/param.h>
-#include <sys/mbuf.h>
-#include <sys/systm.h>
-#include <netinet/in_systm.h>
-#include <netinet/in.h>
-#include <netinet/ip.h>
-#include <machine/in_cksum.h>
-
-/*
- * Checksum routine for Internet Protocol family headers
- *    (Portable Alpha version).
- *
- * This routine is very heavily used in the network
- * code and should be modified for each CPU to be as fast as possible.
- */
-
-#define ADDCARRY(x)  (x > 65535 ? x -= 65535 : x)
-#define REDUCE32							  \
-    {									  \
-	q_util.q = sum;							  \
-	sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3];	  \
-    }
-#define REDUCE16							  \
-    {									  \
-	q_util.q = sum;							  \
-	l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
-	sum = l_util.s[0] + l_util.s[1];				  \
-	ADDCARRY(sum);							  \
-    }
-
-static const u_int32_t in_masks[] = {
-	/*0 bytes*/ /*1 byte*/	/*2 bytes*/ /*3 bytes*/
-	0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF,	/* offset 0 */
-	0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00,	/* offset 1 */
-	0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000,	/* offset 2 */
-	0x00000000, 0xFF000000, 0xFF000000, 0xFF000000,	/* offset 3 */
-};
-
-union l_util {
-	u_int16_t s[2];
-	u_int32_t l;
-};
-union q_util {
-	u_int16_t s[4];
-	u_int32_t l[2];
-	u_int64_t q;
-};
-
-static u_int64_t
-in_cksumdata(const void *buf, int len)
-{
-	const u_int32_t *lw = (const u_int32_t *) buf;
-	u_int64_t sum = 0;
-	u_int64_t prefilled;
-	int offset;
-	union q_util q_util;
-
-	if ((3 & (long) lw) == 0 && len == 20) {
-	     sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4];
-	     REDUCE32;
-	     return sum;
-	}
-
-	if ((offset = 3 & (long) lw) != 0) {
-		const u_int32_t *masks = in_masks + (offset << 2);
-		lw = (u_int32_t *) (((long) lw) - offset);
-		sum = *lw++ & masks[len >= 3 ? 3 : len];
-		len -= 4 - offset;
-		if (len <= 0) {
-			REDUCE32;
-			return sum;
-		}
-	}
-#if 0
-	/*
-	 * Force to cache line boundary.
-	 */
-	offset = 32 - (0x1f & (long) lw);
-	if (offset < 32 && len > offset) {
-		len -= offset;
-		if (4 & offset) {
-			sum += (u_int64_t) lw[0];
-			lw += 1;
-		}
-		if (8 & offset) {
-			sum += (u_int64_t) lw[0] + lw[1];
-			lw += 2;
-		}
-		if (16 & offset) {
-			sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
-			lw += 4;
-		}
-	}
-#endif
-	/*
-	 * access prefilling to start load of next cache line.
-	 * then add current cache line
-	 * save result of prefilling for loop iteration.
-	 */
-	prefilled = lw[0];
-	while ((len -= 32) >= 4) {
-		u_int64_t prefilling = lw[8];
-		sum += prefilled + lw[1] + lw[2] + lw[3]
-			+ lw[4] + lw[5] + lw[6] + lw[7];
-		lw += 8;
-		prefilled = prefilling;
-	}
-	if (len >= 0) {
-		sum += prefilled + lw[1] + lw[2] + lw[3]
-			+ lw[4] + lw[5] + lw[6] + lw[7];
-		lw += 8;
-	} else {
-		len += 32;
-	}
-	while ((len -= 16) >= 0) {
-		sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
-		lw += 4;
-	}
-	len += 16;
-	while ((len -= 4) >= 0) {
-		sum += (u_int64_t) *lw++;
-	}
-	len += 4;
-	if (len > 0)
-		sum += (u_int64_t) (in_masks[len] & *lw);
-	REDUCE32;
-	return sum;
-}
-
-u_short
-in_addword(u_short a, u_short b)
-{
-	u_int64_t sum = a + b;
-
-	ADDCARRY(sum);
-	return (sum);
-}
-
-u_short
-in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c)
-{
-	u_int64_t sum;
-	union q_util q_util;
-	union l_util l_util;
-		    
-	sum = (u_int64_t) a + b + c;
-	REDUCE16;
-	return (sum);
-}
-
-u_short
-in_cksum_skip(struct mbuf *m, int len, int skip)
-{
-	u_int64_t sum = 0;
-	int mlen = 0;
-	int clen = 0;
-	caddr_t addr;
-	union q_util q_util;
-	union l_util l_util;
-
-        len -= skip;
-        for (; skip && m; m = m->m_next) {
-                if (m->m_len > skip) {
-                        mlen = m->m_len - skip;
-			addr = mtod(m, caddr_t) + skip;
-                        goto skip_start;
-                } else {
-                        skip -= m->m_len;
-                }
-        }
-
-	for (; m && len; m = m->m_next) {
-		if (m->m_len == 0)
-			continue;
-		mlen = m->m_len;
-		addr = mtod(m, caddr_t);
-skip_start:
-		if (len < mlen)
-			mlen = len;
-		if ((clen ^ (long) addr) & 1)
-		    sum += in_cksumdata(addr, mlen) << 8;
-		else
-		    sum += in_cksumdata(addr, mlen);
-
-		clen += mlen;
-		len -= mlen;
-	}
-	REDUCE16;
-	return (~sum & 0xffff);
-}
-
-u_int in_cksum_hdr(const struct ip *ip)
-{
-    u_int64_t sum = in_cksumdata(ip, sizeof(struct ip));
-    union q_util q_util;
-    union l_util l_util;
-    REDUCE16;
-    return (~sum & 0xffff);
-}
diff --git a/sys/arm/arm/in_cksum.c b/sys/arm/arm/in_cksum_machdep.c
similarity index 100%
rename from sys/arm/arm/in_cksum.c
rename to sys/arm/arm/in_cksum_machdep.c
diff --git a/sys/arm/include/in_cksum.h b/sys/arm/include/in_cksum.h
index a75433830d73..352d46f07e7b 100644
--- a/sys/arm/include/in_cksum.h
+++ b/sys/arm/include/in_cksum.h
@@ -40,6 +40,9 @@
 #include <sys/cdefs.h>
 
 #ifdef _KERNEL
+
+#define	HAVE_MD_IN_CKSUM
+
 u_short in_cksum(struct mbuf *m, int len);
 u_short in_addword(u_short sum, u_short b);
 u_short in_cksum_skip(struct mbuf *m, int len, int skip);
diff --git a/sys/arm64/arm64/in_cksum.c b/sys/arm64/arm64/in_cksum.c
deleted file mode 100644
index ae02e91d9203..000000000000
--- a/sys/arm64/arm64/in_cksum.c
+++ /dev/null
@@ -1,241 +0,0 @@
-/* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */
-
-/*-
- * Copyright (c) 1988, 1992, 1993
- *	The Regents of the University of California.  All rights reserved.
- * Copyright (c) 1996
- *	Matt Thomas <matt@3am-software.com>
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *	This product includes software developed by the University of
- *	California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- *	@(#)in_cksum.c	8.1 (Berkeley) 6/10/93
- */
-
-#include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
-__FBSDID("$FreeBSD$");
-
-#include <sys/param.h>
-#include <sys/mbuf.h>
-#include <sys/systm.h>
-#include <netinet/in_systm.h>
-#include <netinet/in.h>
-#include <netinet/ip.h>
-#include <machine/in_cksum.h>
-
-/*
- * Checksum routine for Internet Protocol family headers
- *    (Portable Alpha version).
- *
- * This routine is very heavily used in the network
- * code and should be modified for each CPU to be as fast as possible.
- */
-
-#define ADDCARRY(x)  (x > 65535 ? x -= 65535 : x)
-#define REDUCE32							  \
-    {									  \
-	q_util.q = sum;							  \
-	sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3];	  \
-    }
-#define REDUCE16							  \
-    {									  \
-	q_util.q = sum;							  \
-	l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
-	sum = l_util.s[0] + l_util.s[1];				  \
-	ADDCARRY(sum);							  \
-    }
-
-static const u_int32_t in_masks[] = {
-	/*0 bytes*/ /*1 byte*/	/*2 bytes*/ /*3 bytes*/
-	0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF,	/* offset 0 */
-	0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00,	/* offset 1 */
-	0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000,	/* offset 2 */
-	0x00000000, 0xFF000000, 0xFF000000, 0xFF000000,	/* offset 3 */
-};
-
-union l_util {
-	u_int16_t s[2];
-	u_int32_t l;
-};
-union q_util {
-	u_int16_t s[4];
-	u_int32_t l[2];
-	u_int64_t q;
-};
-
-static u_int64_t
-in_cksumdata(const void *buf, int len)
-{
-	const u_int32_t *lw = (const u_int32_t *) buf;
-	u_int64_t sum = 0;
-	u_int64_t prefilled;
-	int offset;
-	union q_util q_util;
-
-	if ((3 & (long) lw) == 0 && len == 20) {
-	     sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4];
-	     REDUCE32;
-	     return sum;
-	}
-
-	if ((offset = 3 & (long) lw) != 0) {
-		const u_int32_t *masks = in_masks + (offset << 2);
-		lw = (u_int32_t *) (((long) lw) - offset);
-		sum = *lw++ & masks[len >= 3 ? 3 : len];
-		len -= 4 - offset;
-		if (len <= 0) {
-			REDUCE32;
-			return sum;
-		}
-	}
-#if 0
-	/*
-	 * Force to cache line boundary.
-	 */
-	offset = 32 - (0x1f & (long) lw);
-	if (offset < 32 && len > offset) {
-		len -= offset;
-		if (4 & offset) {
-			sum += (u_int64_t) lw[0];
-			lw += 1;
-		}
-		if (8 & offset) {
-			sum += (u_int64_t) lw[0] + lw[1];
-			lw += 2;
-		}
-		if (16 & offset) {
-			sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
-			lw += 4;
-		}
-	}
-#endif
-	/*
-	 * access prefilling to start load of next cache line.
-	 * then add current cache line
-	 * save result of prefilling for loop iteration.
-	 */
-	prefilled = lw[0];
-	while ((len -= 32) >= 4) {
-		u_int64_t prefilling = lw[8];
-		sum += prefilled + lw[1] + lw[2] + lw[3]
-			+ lw[4] + lw[5] + lw[6] + lw[7];
-		lw += 8;
-		prefilled = prefilling;
-	}
-	if (len >= 0) {
-		sum += prefilled + lw[1] + lw[2] + lw[3]
-			+ lw[4] + lw[5] + lw[6] + lw[7];
-		lw += 8;
-	} else {
-		len += 32;
-	}
-	while ((len -= 16) >= 0) {
-		sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
-		lw += 4;
-	}
-	len += 16;
-	while ((len -= 4) >= 0) {
-		sum += (u_int64_t) *lw++;
-	}
-	len += 4;
-	if (len > 0)
-		sum += (u_int64_t) (in_masks[len] & *lw);
-	REDUCE32;
-	return sum;
-}
-
-u_short
-in_addword(u_short a, u_short b)
-{
-	u_int64_t sum = a + b;
-
-	ADDCARRY(sum);
-	return (sum);
-}
-
-u_short
-in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c)
-{
-	u_int64_t sum;
-	union q_util q_util;
-	union l_util l_util;
-		    
-	sum = (u_int64_t) a + b + c;
-	REDUCE16;
-	return (sum);
-}
-
-u_short
-in_cksum_skip(struct mbuf *m, int len, int skip)
-{
-	u_int64_t sum = 0;
-	int mlen = 0;
-	int clen = 0;
-	caddr_t addr;
-	union q_util q_util;
-	union l_util l_util;
-
-        len -= skip;
-        for (; skip && m; m = m->m_next) {
-                if (m->m_len > skip) {
-                        mlen = m->m_len - skip;
-			addr = mtod(m, caddr_t) + skip;
-                        goto skip_start;
-                } else {
-                        skip -= m->m_len;
-                }
-        }
-
-	for (; m && len; m = m->m_next) {
-		if (m->m_len == 0)
-			continue;
-		mlen = m->m_len;
-		addr = mtod(m, caddr_t);
-skip_start:
-		if (len < mlen)
-			mlen = len;
-		if ((clen ^ (long) addr) & 1)
-		    sum += in_cksumdata(addr, mlen) << 8;
-		else
-		    sum += in_cksumdata(addr, mlen);
-
-		clen += mlen;
-		len -= mlen;
-	}
-	REDUCE16;
-	return (~sum & 0xffff);
-}
-
-u_int in_cksum_hdr(const struct ip *ip)
-{
-    u_int64_t sum = in_cksumdata(ip, sizeof(struct ip));
-    union q_util q_util;
-    union l_util l_util;
-    REDUCE16;
-    return (~sum & 0xffff);
-}
diff --git a/sys/conf/files b/sys/conf/files
index f25508f1fded..8936cdaf5bd3 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -4333,6 +4333,7 @@ netinet/accf_http.c		optional accept_filter_http inet
 netinet/if_ether.c		optional inet ether
 netinet/igmp.c			optional inet
 netinet/in.c			optional inet
+netinet/in_cksum.c		optional inet | inet6
 netinet/in_debug.c		optional inet ddb
 netinet/in_kdtrace.c		optional inet | inet6
 netinet/ip_carp.c		optional inet carp | inet6 carp
diff --git a/sys/conf/files.amd64 b/sys/conf/files.amd64
index 6b51c1a5a55d..9a741906c868 100644
--- a/sys/conf/files.amd64
+++ b/sys/conf/files.amd64
@@ -62,7 +62,6 @@ amd64/amd64/exception.S		standard
 amd64/amd64/exec_machdep.c	standard
 amd64/amd64/fpu.c		standard
 amd64/amd64/gdb_machdep.c	optional	gdb
-amd64/amd64/in_cksum.c		optional	inet | inet6
 amd64/amd64/initcpu.c		standard
 amd64/amd64/io.c		optional	io
 amd64/amd64/locore.S		standard	no-obj
diff --git a/sys/conf/files.arm b/sys/conf/files.arm
index ce9c4933a024..4a5e9cc0bac9 100644
--- a/sys/conf/files.arm
+++ b/sys/conf/files.arm
@@ -35,8 +35,8 @@ arm/arm/gic.c			optional	gic
 arm/arm/gic_fdt.c		optional	gic fdt
 arm/arm/gic_if.m		optional	gic
 arm/arm/identcpu-v6.c		standard
-arm/arm/in_cksum.c		optional	inet | inet6
 arm/arm/in_cksum_arm.S		optional	inet | inet6
+arm/arm/in_cksum_machdep.c	optional	inet | inet6
 kern/subr_intr.c		standard
 arm/arm/locore.S		standard	no-obj
 arm/arm/hypervisor-stub.S	standard
diff --git a/sys/conf/files.arm64 b/sys/conf/files.arm64
index 2b7c8bc569c7..722a33da812d 100644
--- a/sys/conf/files.arm64
+++ b/sys/conf/files.arm64
@@ -56,7 +56,6 @@ arm64/arm64/gic_v3.c				standard
 arm64/arm64/gic_v3_acpi.c			optional acpi
 arm64/arm64/gic_v3_fdt.c			optional fdt
 arm64/arm64/identcpu.c				standard
-arm64/arm64/in_cksum.c				optional inet | inet6
 arm64/arm64/locore.S				standard no-obj
 arm64/arm64/machdep.c				standard
 arm64/arm64/machdep_boot.c			standard
diff --git a/sys/conf/files.i386 b/sys/conf/files.i386
index 0c681d6a84a0..bca5f04aeb1d 100644
--- a/sys/conf/files.i386
+++ b/sys/conf/files.i386
@@ -108,7 +108,7 @@ i386/i386/elf_machdep.c		standard
 i386/i386/exception.s		standard
 i386/i386/gdb_machdep.c		optional gdb
 i386/i386/geode.c		optional cpu_geode
-i386/i386/in_cksum.c		optional inet | inet6
+i386/i386/in_cksum_machdep.c	optional inet | inet6
 i386/i386/initcpu.c		standard
 i386/i386/io.c			optional io
 i386/i386/k6_mem.c		optional mem
diff --git a/sys/conf/files.mips b/sys/conf/files.mips
index 6211c90f4e7e..777d4af57c06 100644
--- a/sys/conf/files.mips
+++ b/sys/conf/files.mips
@@ -20,7 +20,6 @@ mips/mips/exception.S			standard
 mips/mips/fp.S				standard
 mips/mips/freebsd32_machdep.c		optional	compat_freebsd32
 mips/mips/gdb_machdep.c			standard
-mips/mips/in_cksum.c			optional	inet
 mips/mips/libkern_machdep.c		standard
 mips/mips/locore.S			standard	no-obj
 mips/mips/machdep.c			standard
diff --git a/sys/conf/files.powerpc b/sys/conf/files.powerpc
index 5d10740ce41d..25fdfea388b9 100644
--- a/sys/conf/files.powerpc
+++ b/sys/conf/files.powerpc
@@ -254,7 +254,6 @@ powerpc/powerpc/elf64_machdep.c	optional	powerpc64 | powerpc64le
 powerpc/powerpc/exec_machdep.c	standard
 powerpc/powerpc/fpu.c		standard
 powerpc/powerpc/gdb_machdep.c	optional	gdb
-powerpc/powerpc/in_cksum.c	optional	inet | inet6
 powerpc/powerpc/interrupt.c	standard
 powerpc/powerpc/intr_machdep.c	standard
 powerpc/powerpc/iommu_if.m	standard
diff --git a/sys/conf/files.riscv b/sys/conf/files.riscv
index 72939b42d67d..e343b9b7f9b3 100644
--- a/sys/conf/files.riscv
+++ b/sys/conf/files.riscv
@@ -47,7 +47,6 @@ riscv/riscv/elf_machdep.c	standard
 riscv/riscv/exception.S		standard
 riscv/riscv/exec_machdep.c	standard
 riscv/riscv/intr_machdep.c	standard
-riscv/riscv/in_cksum.c		optional	inet | inet6
 riscv/riscv/identcpu.c		standard
 riscv/riscv/locore.S		standard	no-obj
 riscv/riscv/machdep.c		standard
diff --git a/sys/i386/i386/in_cksum.c b/sys/i386/i386/in_cksum_machdep.c
similarity index 100%
rename from sys/i386/i386/in_cksum.c
rename to sys/i386/i386/in_cksum_machdep.c
diff --git a/sys/i386/include/in_cksum.h b/sys/i386/include/in_cksum.h
index a8214e97cd9a..6b9c62942561 100644
--- a/sys/i386/include/in_cksum.h
+++ b/sys/i386/include/in_cksum.h
@@ -118,6 +118,9 @@ in_pseudo(u_int sum, u_int b, u_int c)
 #endif
 
 #ifdef _KERNEL
+
+#define	HAVE_MD_IN_CKSUM
+
 #if !defined(__GNUCLIKE_ASM)
 #if defined(IPVERSION) && (IPVERSION == 4)
 u_int in_cksum_hdr(const struct ip *ip);
diff --git a/sys/mips/mips/in_cksum.c b/sys/netinet/in_cksum.c
similarity index 98%
rename from sys/mips/mips/in_cksum.c
rename to sys/netinet/in_cksum.c
index 8f9a2d9de106..581950c8afa4 100644
--- a/sys/mips/mips/in_cksum.c
+++ b/sys/netinet/in_cksum.c
@@ -48,6 +48,11 @@ __FBSDID("$FreeBSD$");
 #include <netinet/ip.h>
 #include <machine/in_cksum.h>
 
+/*
+ * These implementations may be overridden on a per-platform basis.
+ */
+#ifndef HAVE_MD_IN_CKSUM
+
 /*
  * Checksum routine for Internet Protocol family headers
  *    (Portable Alpha version).
@@ -248,3 +253,5 @@ u_int in_cksum_hdr(const struct ip *ip)
 	REDUCE16;
 	return (~sum & 0xffff);
 }
+
+#endif /* !HAVE_MD_IN_CKSUM */
diff --git a/sys/powerpc/powerpc/in_cksum.c b/sys/powerpc/powerpc/in_cksum.c
deleted file mode 100644
index 906dc7e8d9a3..000000000000
--- a/sys/powerpc/powerpc/in_cksum.c
+++ /dev/null
@@ -1,253 +0,0 @@
-/* $FreeBSD$ */
-/* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */
-
-/*-
- * SPDX-License-Identifier: BSD-4-Clause
- *
- * Copyright (c) 1988, 1992, 1993
- *	The Regents of the University of California.  All rights reserved.
- * Copyright (c) 1996
- *	Matt Thomas <matt@3am-software.com>
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *	This product includes software developed by the University of
- *	California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- *	@(#)in_cksum.c	8.1 (Berkeley) 6/10/93
- */
-
-#include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
-
-#include <sys/endian.h>
-#include <sys/param.h>
-#include <sys/mbuf.h>
-#include <sys/systm.h>
-#include <netinet/in_systm.h>
-#include <netinet/in.h>
-#include <netinet/ip.h>
-#include <machine/in_cksum.h>
-
-/*
- * Checksum routine for Internet Protocol family headers
- *    (Portable Alpha version).
- *
- * This routine is very heavily used in the network
- * code and should be modified for each CPU to be as fast as possible.
- */
-
-#define ADDCARRY(x)  (x > 65535 ? x -= 65535 : x)
-#define REDUCE32							  \
-    {									  \
-	q_util.q = sum;							  \
-	sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3];	  \
-    }
-#define REDUCE16							  \
-    {									  \
-	q_util.q = sum;							  \
-	l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
-	sum = l_util.s[0] + l_util.s[1];				  \
-	ADDCARRY(sum);							  \
-    }
-
-static const u_int32_t in_masks[] = {
-#if _BYTE_ORDER == _LITTLE_ENDIAN
-	/*0 bytes*/ /*1 byte*/	/*2 bytes*/ /*3 bytes*/
-	0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF,	/* offset 0 */
-	0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00,	/* offset 1 */
-	0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000,	/* offset 2 */
-	0x00000000, 0xFF000000, 0xFF000000, 0xFF000000,	/* offset 3 */
-#else
-	/*0 bytes*/ /*1 byte*/	/*2 bytes*/ /*3 bytes*/
-	0x00000000, 0xFF000000, 0xFFFF0000, 0xFFFFFF00,	/* offset 0 */
-	0x00000000, 0x00FF0000, 0x00FFFF00, 0x00FFFFFF,	/* offset 1 */
-	0x00000000, 0x0000FF00, 0x0000FFFF, 0x0000FFFF,	/* offset 2 */
-	0x00000000, 0x000000FF, 0x000000FF, 0x000000FF,	/* offset 3 */
-#endif
-};
-
-union l_util {
-	u_int16_t s[2];
-	u_int32_t l;
-};
-union q_util {
-	u_int16_t s[4];
-	u_int32_t l[2];
-	u_int64_t q;
-};
-
-static u_int64_t
-in_cksumdata(const void *buf, int len)
-{
-	const u_int32_t *lw = (const u_int32_t *) buf;
-	u_int64_t sum = 0;
-	u_int64_t prefilled;
-	int offset;
-	union q_util q_util;
-
-	if ((3 & (long) lw) == 0 && len == 20) {
-	     sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4];
-	     REDUCE32;
-	     return sum;
-	}
-
-	if ((offset = 3 & (long) lw) != 0) {
-		const u_int32_t *masks = in_masks + (offset << 2);
-		lw = (u_int32_t *) (((long) lw) - offset);
-		sum = *lw++ & masks[len >= 3 ? 3 : len];
-		len -= 4 - offset;
-		if (len <= 0) {
-			REDUCE32;
-			return sum;
-		}
-	}
-#if 0
-	/*
-	 * Force to cache line boundary.
-	 */
-	offset = 32 - (0x1f & (long) lw);
-	if (offset < 32 && len > offset) {
-		len -= offset;
-		if (4 & offset) {
-			sum += (u_int64_t) lw[0];
-			lw += 1;
-		}
-		if (8 & offset) {
-			sum += (u_int64_t) lw[0] + lw[1];
-			lw += 2;
-		}
-		if (16 & offset) {
-			sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
-			lw += 4;
-		}
-	}
-#endif
-	/*
-	 * access prefilling to start load of next cache line.
-	 * then add current cache line
-	 * save result of prefilling for loop iteration.
-	 */
-	prefilled = lw[0];
-	while ((len -= 32) >= 4) {
-		u_int64_t prefilling = lw[8];
-		sum += prefilled + lw[1] + lw[2] + lw[3]
-			+ lw[4] + lw[5] + lw[6] + lw[7];
-		lw += 8;
-		prefilled = prefilling;
-	}
-	if (len >= 0) {
-		sum += prefilled + lw[1] + lw[2] + lw[3]
-			+ lw[4] + lw[5] + lw[6] + lw[7];
-		lw += 8;
-	} else {
-		len += 32;
-	}
-	while ((len -= 16) >= 0) {
-		sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
-		lw += 4;
-	}
-	len += 16;
-	while ((len -= 4) >= 0) {
-		sum += (u_int64_t) *lw++;
-	}
-	len += 4;
-	if (len > 0)
-		sum += (u_int64_t) (in_masks[len] & *lw);
-	REDUCE32;
-	return sum;
-}
-
-u_short
-in_addword(u_short a, u_short b)
-{
-	u_int64_t sum = a + b;
-
-	ADDCARRY(sum);
-	return (sum);
-}
-
-u_short
-in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c)
-{
-	u_int64_t sum;
-	union q_util q_util;
-	union l_util l_util;
-		    
-	sum = (u_int64_t) a + b + c;
-	REDUCE16;
-	return (sum);
-}
-
-u_short
-in_cksum_skip(struct mbuf *m, int len, int skip)
-{
-	u_int64_t sum = 0;
-	int mlen = 0;
-	int clen = 0;
-	caddr_t addr;
-	union q_util q_util;
-	union l_util l_util;
-
-        len -= skip;
-        for (; skip && m; m = m->m_next) {
-                if (m->m_len > skip) {
-                        mlen = m->m_len - skip;
-			addr = mtod(m, caddr_t) + skip;
-                        goto skip_start;
-                } else {
-                        skip -= m->m_len;
-                }
-        }
-
-	for (; m && len; m = m->m_next) {
-		if (m->m_len == 0)
-			continue;
-		mlen = m->m_len;
-		addr = mtod(m, caddr_t);
-skip_start:
-		if (len < mlen)
-			mlen = len;
-
-		if ((clen ^ (long) addr) & 1)
-		    sum += in_cksumdata(addr, mlen) << 8;
-		else
-		    sum += in_cksumdata(addr, mlen);
-
-		clen += mlen;
-		len -= mlen;
-	}
-	REDUCE16;
-	return (~sum & 0xffff);
-}
-
-u_int in_cksum_hdr(const struct ip *ip)
-{
-    u_int64_t sum = in_cksumdata(ip, sizeof(struct ip));
-    union q_util q_util;
-    union l_util l_util;
-    REDUCE16;
-    return (~sum & 0xffff);
-}
diff --git a/sys/riscv/riscv/in_cksum.c b/sys/riscv/riscv/in_cksum.c
deleted file mode 100644
index 30e90f043cc3..000000000000
--- a/sys/riscv/riscv/in_cksum.c
+++ /dev/null
@@ -1,243 +0,0 @@
-/* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */
-
-/*-
- * SPDX-License-Identifier: BSD-4-Clause
- *
- * Copyright (c) 1988, 1992, 1993
- *	The Regents of the University of California.  All rights reserved.
- * Copyright (c) 1996
- *	Matt Thomas <matt@3am-software.com>
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
*** 225 LINES SKIPPED ***