1 files changed, 133 insertions, 0 deletions
diff --git a/arch/s390/include/asm/checksum.h b/arch/s390/include/asm/checksum.h
new file mode 100644
index 000000000..69837eec2
--- /dev/null
+++ b/arch/s390/include/asm/checksum.h
@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *    S390 fast network checksum routines
+ *
+ *  S390 version
+ *    Copyright IBM Corp. 1999
+ *    Author(s): Ulrich Hild        (first version)
+ *               Martin Schwidefsky (heavily optimized CKSM version)
+ *               D.J. Barrow        (third attempt) 
+ */
+
+#ifndef _S390_CHECKSUM_H
+#define _S390_CHECKSUM_H
+
+#include <linux/kasan-checks.h>
+#include <linux/in6.h>
+
+/*
+ * Computes the checksum of a memory block at buff, length len,
+ * and adds in "sum" (32-bit).
+ *
+ * Returns a 32-bit number suitable for feeding into itself
+ * or csum_tcpudp_magic.
+ *
+ * This function must be called with even lengths, except
+ * for the last fragment, which may be odd.
+ *
+ * It's best to have buff aligned on a 32-bit boundary.
+ */
+static inline __wsum csum_partial(const void *buff, int len, __wsum sum)
+{
+	union register_pair rp = {
+		.even = (unsigned long) buff,
+		.odd = (unsigned long) len,
+	};
+
+	kasan_check_read(buff, len);
+	asm volatile(
+		"0:	cksm	%[sum],%[rp]\n"
+		"	jo	0b\n"
+		: [sum] "+&d" (sum), [rp] "+&d" (rp.pair) : : "cc", "memory");
+	return sum;
+}
+
+/*
+ * Fold a partial checksum without adding pseudo headers.
+ */
+static inline __sum16 csum_fold(__wsum sum)
+{
+	u32 csum = (__force u32) sum;
+
+	csum += (csum >> 16) | (csum << 16);
+	csum >>= 16;
+	return (__force __sum16) ~csum;
+}
+
+/*
+ * This is a version of ip_compute_csum() optimized for IP headers,
+ * which always checksums on 4 octet boundaries.
+ */
+static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
+{
+	__u64 csum = 0;
+	__u32 *ptr = (u32 *)iph;
+
+	csum += *ptr++;
+	csum += *ptr++;
+	csum += *ptr++;
+	csum += *ptr++;
+	ihl -= 4;
+	while (ihl--)
+		csum += *ptr++;
+	csum += (csum >> 32) | (csum << 32);
+	return csum_fold((__force __wsum)(csum >> 32));
+}
+
+/*
+ * Computes the checksum of the TCP/UDP pseudo-header.
+ * Returns a 32-bit checksum.
+ */
+static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
+					__u8 proto, __wsum sum)
+{
+	__u64 csum = (__force __u64)sum;
+
+	csum += (__force __u32)saddr;
+	csum += (__force __u32)daddr;
+	csum += len;
+	csum += proto;
+	csum += (csum >> 32) | (csum << 32);
+	return (__force __wsum)(csum >> 32);
+}
+
+/*
+ * Computes the checksum of the TCP/UDP pseudo-header.
+ * Returns a 16-bit checksum, already complemented.
+ */
+static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
+					__u8 proto, __wsum sum)
+{
+	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
+}
+
+/*
+ * Used for miscellaneous IP-like checksums, mainly icmp.
+ */
+static inline __sum16 ip_compute_csum(const void *buff, int len)
+{
+	return csum_fold(csum_partial(buff, len, 0));
+}
+
+#define _HAVE_ARCH_IPV6_CSUM
+static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
+				      const struct in6_addr *daddr,
+				      __u32 len, __u8 proto, __wsum csum)
+{
+	__u64 sum = (__force __u64)csum;
+
+	sum += (__force __u32)saddr->s6_addr32[0];
+	sum += (__force __u32)saddr->s6_addr32[1];
+	sum += (__force __u32)saddr->s6_addr32[2];
+	sum += (__force __u32)saddr->s6_addr32[3];
+	sum += (__force __u32)daddr->s6_addr32[0];
+	sum += (__force __u32)daddr->s6_addr32[1];
+	sum += (__force __u32)daddr->s6_addr32[2];
+	sum += (__force __u32)daddr->s6_addr32[3];
+	sum += len;
+	sum += proto;
+	sum += (sum >> 32) | (sum << 32);
+	return csum_fold((__force __wsum)(sum >> 32));
+}
+
+#endif /* _S390_CHECKSUM_H */