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-rw-r--r--arch/s390/include/asm/checksum.h166
1 files changed, 166 insertions, 0 deletions
diff --git a/arch/s390/include/asm/checksum.h b/arch/s390/include/asm/checksum.h
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+#ifndef _S390_CHECKSUM_H
+#define _S390_CHECKSUM_H
+
+/*
+ * include/asm-s390/checksum.h
+ * S390 fast network checksum routines
+ * see also arch/S390/lib/checksum.c
+ *
+ * S390 version
+ * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ * Author(s): Ulrich Hild (first version)
+ * Martin Schwidefsky (heavily optimized CKSM version)
+ * D.J. Barrow (third attempt)
+ */
+
+#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. If we catch an exception
+ * then zero the rest of the buffer.
+ */
+static inline __wsum
+csum_partial_copy_from_user(const void __user *src, void *dst,
+ int len, __wsum sum,
+ int *err_ptr)
+{
+ int missing;
+
+ missing = copy_from_user(dst, src, len);
+ if (missing) {
+ memset(dst + len - missing, 0, missing);
+ *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)
+{
+#ifndef __s390x__
+ register_pair rp;
+
+ asm volatile(
+ " slr %N1,%N1\n" /* %0 = H L */
+ " lr %1,%0\n" /* %0 = H L, %1 = H L 0 0 */
+ " srdl %1,16\n" /* %0 = H L, %1 = 0 H L 0 */
+ " alr %1,%N1\n" /* %0 = H L, %1 = L H L 0 */
+ " alr %0,%1\n" /* %0 = H+L+C L+H */
+ " srl %0,16\n" /* %0 = H+L+C */
+ : "+&d" (sum), "=d" (rp) : : "cc");
+#else /* __s390x__ */
+ asm volatile(
+ " sr 3,3\n" /* %0 = H*65536 + L */
+ " lr 2,%0\n" /* %0 = H L, 2/3 = H L / 0 0 */
+ " srdl 2,16\n" /* %0 = H L, 2/3 = 0 H / L 0 */
+ " alr 2,3\n" /* %0 = H L, 2/3 = L H / L 0 */
+ " alr %0,2\n" /* %0 = H+L+C L+H */
+ " srl %0,16\n" /* %0 = H+L+C */
+ : "+&d" (sum) : : "cc", "2", "3");
+#endif /* __s390x__ */
+ return (__force __sum16) ~sum;
+}
+
+/*
+ * 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 */
+
+