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-rw-r--r--include/asm-s390/checksum.h264
1 files changed, 264 insertions, 0 deletions
diff --git a/include/asm-s390/checksum.h b/include/asm-s390/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 unsigned int
+csum_partial(const unsigned char * buff, int len, unsigned int sum)
+{
+ /*
+ * Experiments with ethernet and slip connections show that buf
+ * is aligned on either a 2-byte or 4-byte boundary.
+ */
+#ifndef __s390x__
+ register_pair rp;
+
+ rp.subreg.even = (unsigned long) buff;
+ rp.subreg.odd = (unsigned long) len;
+ __asm__ __volatile__ (
+ "0: cksm %0,%1\n" /* do checksum on longs */
+ " jo 0b\n"
+ : "+&d" (sum), "+&a" (rp) : : "cc", "memory" );
+#else /* __s390x__ */
+ __asm__ __volatile__ (
+ " lgr 2,%1\n" /* address in gpr 2 */
+ " lgfr 3,%2\n" /* length in gpr 3 */
+ "0: cksm %0,2\n" /* do checksum on longs */
+ " jo 0b\n"
+ : "+&d" (sum)
+ : "d" (buff), "d" (len)
+ : "cc", "memory", "2", "3" );
+#endif /* __s390x__ */
+ return sum;
+}
+
+/*
+ * csum_partial as an inline function
+ */
+static inline unsigned int
+csum_partial_inline(const unsigned char * buff, int len, unsigned int sum)
+{
+#ifndef __s390x__
+ register_pair rp;
+
+ rp.subreg.even = (unsigned long) buff;
+ rp.subreg.odd = (unsigned long) len;
+ __asm__ __volatile__ (
+ "0: cksm %0,%1\n" /* do checksum on longs */
+ " jo 0b\n"
+ : "+&d" (sum), "+&a" (rp) : : "cc", "memory" );
+#else /* __s390x__ */
+ __asm__ __volatile__ (
+ " lgr 2,%1\n" /* address in gpr 2 */
+ " lgfr 3,%2\n" /* length in gpr 3 */
+ "0: cksm %0,2\n" /* do checksum on longs */
+ " jo 0b\n"
+ : "+&d" (sum)
+ : "d" (buff), "d" (len)
+ : "cc", "memory", "2", "3" );
+#endif /* __s390x__ */
+ 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 unsigned int
+csum_partial_copy_from_user(const char __user *src, char *dst,
+ int len, unsigned int 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 unsigned int
+csum_partial_copy_nocheck (const char *src, char *dst, int len, unsigned int sum)
+{
+ memcpy(dst,src,len);
+ return csum_partial_inline(dst, len, sum);
+}
+
+/*
+ * Fold a partial checksum without adding pseudo headers
+ */
+static inline unsigned short
+csum_fold(unsigned int 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, R2/R3 = H L / 0 0 */
+ " srdl 2,16\n" /* %0 = H L, R2/R3 = 0 H / L 0 */
+ " alr 2,3\n" /* %0 = H L, R2/R3 = 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 ((unsigned short) ~sum);
+}
+
+/*
+ * This is a version of ip_compute_csum() optimized for IP headers,
+ * which always checksum on 4 octet boundaries.
+ *
+ */
+static inline unsigned short
+ip_fast_csum(unsigned char *iph, unsigned int ihl)
+{
+ unsigned long sum;
+#ifndef __s390x__
+ register_pair rp;
+
+ rp.subreg.even = (unsigned long) iph;
+ rp.subreg.odd = (unsigned long) ihl*4;
+ __asm__ __volatile__ (
+ " sr %0,%0\n" /* set sum to zero */
+ "0: cksm %0,%1\n" /* do checksum on longs */
+ " jo 0b\n"
+ : "=&d" (sum), "+&a" (rp) : : "cc", "memory" );
+#else /* __s390x__ */
+ __asm__ __volatile__ (
+ " slgr %0,%0\n" /* set sum to zero */
+ " lgr 2,%1\n" /* address in gpr 2 */
+ " lgfr 3,%2\n" /* length in gpr 3 */
+ "0: cksm %0,2\n" /* do checksum on ints */
+ " jo 0b\n"
+ : "=&d" (sum)
+ : "d" (iph), "d" (ihl*4)
+ : "cc", "memory", "2", "3" );
+#endif /* __s390x__ */
+ return csum_fold(sum);
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 32-bit checksum
+ */
+static inline unsigned int
+csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
+ unsigned short len, unsigned short proto,
+ unsigned int sum)
+{
+#ifndef __s390x__
+ __asm__ __volatile__ (
+ " alr %0,%1\n" /* sum += saddr */
+ " brc 12,0f\n"
+ " ahi %0,1\n" /* add carry */
+ "0:"
+ : "+&d" (sum) : "d" (saddr) : "cc" );
+ __asm__ __volatile__ (
+ " alr %0,%1\n" /* sum += daddr */
+ " brc 12,1f\n"
+ " ahi %0,1\n" /* add carry */
+ "1:"
+ : "+&d" (sum) : "d" (daddr) : "cc" );
+ __asm__ __volatile__ (
+ " alr %0,%1\n" /* sum += (len<<16) + (proto<<8) */
+ " brc 12,2f\n"
+ " ahi %0,1\n" /* add carry */
+ "2:"
+ : "+&d" (sum)
+ : "d" (((unsigned int) len<<16) + (unsigned int) proto)
+ : "cc" );
+#else /* __s390x__ */
+ __asm__ __volatile__ (
+ " lgfr %0,%0\n"
+ " algr %0,%1\n" /* sum += saddr */
+ " brc 12,0f\n"
+ " aghi %0,1\n" /* add carry */
+ "0: algr %0,%2\n" /* sum += daddr */
+ " brc 12,1f\n"
+ " aghi %0,1\n" /* add carry */
+ "1: algfr %0,%3\n" /* sum += (len<<16) + proto */
+ " brc 12,2f\n"
+ " aghi %0,1\n" /* add carry */
+ "2: srlg 0,%0,32\n"
+ " alr %0,0\n" /* fold to 32 bits */
+ " brc 12,3f\n"
+ " ahi %0,1\n" /* add carry */
+ "3: llgfr %0,%0"
+ : "+&d" (sum)
+ : "d" (saddr), "d" (daddr),
+ "d" (((unsigned int) len<<16) + (unsigned int) proto)
+ : "cc", "0" );
+#endif /* __s390x__ */
+ return sum;
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+
+static inline unsigned short int
+csum_tcpudp_magic(unsigned long saddr, unsigned long daddr,
+ unsigned short len, unsigned short proto,
+ unsigned int 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 unsigned short
+ip_compute_csum(unsigned char * buff, int len)
+{
+ return csum_fold(csum_partial(buff, len, 0));
+}
+
+#endif /* _S390_CHECKSUM_H */
+
+
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