checksum_64.h

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#ifndef _ASM_X86_CHECKSUM_64_H
#define _ASM_X86_CHECKSUM_64_H

/*
 * Checksums for x86-64
 * Copyright 2002 by Andi Kleen, SuSE Labs
 * with some code from asm-x86/checksum.h
 */

#include <linux/compiler.h>
#include <asm/uaccess.h>
#include <asm/byteorder.h>

static inline __sum16 csum_fold(__wsum sum)
{
    asm("  addl %1,%0\n"
        "  adcl $0xffff,%0"
        : "=r" (sum)
        : "r" ((__force u32)sum << 16),
          "0" ((__force u32)sum & 0xffff0000));
    return (__force __sum16)(~(__force u32)sum >> 16);
}

/*
 *  This is a version of ip_compute_csum() optimized for IP headers,
 *  which always checksum on 4 octet boundaries.
 *
 *  By Jorge Cwik <[email protected]>, adapted for linux by
 *  Arnt Gulbrandsen.
 */

static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
{
    unsigned int sum;

    asm("  movl (%1), %0\n"
        "  subl $4, %2\n"
        "  jbe 2f\n"
        "  addl 4(%1), %0\n"
        "  adcl 8(%1), %0\n"
        "  adcl 12(%1), %0\n"
        "1: adcl 16(%1), %0\n"
        "  lea 4(%1), %1\n"
        "  decl %2\n"
        "  jne  1b\n"
        "  adcl $0, %0\n"
        "  movl %0, %2\n"
        "  shrl $16, %0\n"
        "  addw %w2, %w0\n"
        "  adcl $0, %0\n"
        "  notl %0\n"
        "2:"
    /* Since the input registers which are loaded with iph and ihl
       are modified, we must also specify them as outputs, or gcc
       will assume they contain their original values. */
        : "=r" (sum), "=r" (iph), "=r" (ihl)
        : "1" (iph), "2" (ihl)
        : "memory");
    return (__force __sum16)sum;
}

static inline __wsum
csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
           unsigned short proto, __wsum sum)
{
    asm("  addl %1, %0\n"
        "  adcl %2, %0\n"
        "  adcl %3, %0\n"
        "  adcl $0, %0\n"
        : "=r" (sum)
        : "g" (daddr), "g" (saddr),
          "g" ((len + proto)<<8), "0" (sum));
    return sum;
}


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));
}

extern __wsum csum_partial(const void *buff, int len, __wsum sum);

#define  _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 1
#define HAVE_CSUM_COPY_USER 1


/* Do not call this directly. Use the wrappers below */
extern __wsum csum_partial_copy_generic(const void *src, const void *dst,
                    int len, __wsum sum,
                    int *src_err_ptr, int *dst_err_ptr);


extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
                      int len, __wsum isum, int *errp);
extern __wsum csum_partial_copy_to_user(const void *src, void __user *dst,
                    int len, __wsum isum, int *errp);
extern __wsum csum_partial_copy_nocheck(const void *src, void *dst,
                    int len, __wsum sum);

/* Old names. To be removed. */
#define csum_and_copy_to_user csum_partial_copy_to_user
#define csum_and_copy_from_user csum_partial_copy_from_user

extern __sum16 ip_compute_csum(const void *buff, int len);

struct in6_addr;

#define _HAVE_ARCH_IPV6_CSUM 1
extern __sum16
csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
        __u32 len, unsigned short proto, __wsum sum);

static inline unsigned add32_with_carry(unsigned a, unsigned b)
{
    asm("addl %2,%0\n\t"
        "adcl $0,%0"
        : "=r" (a)
        : "0" (a), "r" (b));
    return a;
}

#endif /* _ASM_X86_CHECKSUM_64_H */