From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/s390/include/asm/checksum.h | 140 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 140 insertions(+)
 create mode 100644 arch/s390/include/asm/checksum.h

(limited to 'arch/s390/include/asm/checksum.h')

diff --git a/arch/s390/include/asm/checksum.h b/arch/s390/include/asm/checksum.h
new file mode 100644
index 000000000..740364856
--- /dev/null
+++ b/arch/s390/include/asm/checksum.h
@@ -0,0 +1,140 @@
+/*
+ *    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 <asm/uaccess.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)
+{
+	register unsigned long reg2 asm("2") = (unsigned long) buff;
+	register unsigned long reg3 asm("3") = (unsigned long) len;
+
+	asm volatile(
+		"0:	cksm	%0,%1\n"	/* do checksum on longs */
+		"	jo	0b\n"
+		: "+d" (sum), "+d" (reg2), "+d" (reg3) : : "cc", "memory");
+	return sum;
+}
+
+/*
+ * the same as csum_partial_copy, but copies from user space.
+ *
+ * here even more important to align src and dst on a 32-bit (or even
+ * better 64-bit) boundary
+ *
+ * Copy from userspace and compute checksum.
+ */
+static inline __wsum
+csum_partial_copy_from_user(const void __user *src, void *dst,
+                                          int len, __wsum sum,
+                                          int *err_ptr)
+{
+	if (unlikely(copy_from_user(dst, src, len)))
+		*err_ptr = -EFAULT;
+	return csum_partial(dst, len, sum);
+}
+
+
+static inline __wsum
+csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum)
+{
+        memcpy(dst,src,len);
+	return csum_partial(dst, len, 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 checksum on 4 octet boundaries.
+ *
+ */
+static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
+{
+	return csum_fold(csum_partial(iph, ihl*4, 0));
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 32-bit checksum
+ */
+static inline __wsum
+csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
+                   unsigned short len, unsigned short proto,
+                   __wsum sum)
+{
+	__u32 csum = (__force __u32)sum;
+
+	csum += (__force __u32)saddr;
+	if (csum < (__force __u32)saddr)
+		csum++;
+
+	csum += (__force __u32)daddr;
+	if (csum < (__force __u32)daddr)
+		csum++;
+
+	csum += len + proto;
+	if (csum < len + proto)
+		csum++;
+
+	return (__force __wsum)csum;
+}
+
+/*
+ * 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,
+                  unsigned short len, unsigned short proto,
+                  __wsum sum)
+{
+	return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
+}
+
+/*
+ * this routine is used for miscellaneous IP-like checksums, mainly
+ * in icmp.c
+ */
+
+static inline __sum16 ip_compute_csum(const void *buff, int len)
+{
+	return csum_fold(csum_partial(buff, len, 0));
+}
+
+#endif /* _S390_CHECKSUM_H */
+
+
-- 
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