364 строки
8.3 KiB
C
364 строки
8.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* csum_partial_copy - do IP checksumming and copy
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*
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* (C) Copyright 1996 Linus Torvalds
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* accelerated versions (and 21264 assembly versions ) contributed by
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* Rick Gorton <rick.gorton@alpha-processor.com>
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*
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* Don't look at this too closely - you'll go mad. The things
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* we do for performance..
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*/
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/uaccess.h>
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#include <net/checksum.h>
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#define ldq_u(x,y) \
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__asm__ __volatile__("ldq_u %0,%1":"=r" (x):"m" (*(const unsigned long *)(y)))
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#define stq_u(x,y) \
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__asm__ __volatile__("stq_u %1,%0":"=m" (*(unsigned long *)(y)):"r" (x))
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#define extql(x,y,z) \
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__asm__ __volatile__("extql %1,%2,%0":"=r" (z):"r" (x),"r" (y))
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#define extqh(x,y,z) \
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__asm__ __volatile__("extqh %1,%2,%0":"=r" (z):"r" (x),"r" (y))
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#define mskql(x,y,z) \
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__asm__ __volatile__("mskql %1,%2,%0":"=r" (z):"r" (x),"r" (y))
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#define mskqh(x,y,z) \
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__asm__ __volatile__("mskqh %1,%2,%0":"=r" (z):"r" (x),"r" (y))
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#define insql(x,y,z) \
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__asm__ __volatile__("insql %1,%2,%0":"=r" (z):"r" (x),"r" (y))
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#define insqh(x,y,z) \
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__asm__ __volatile__("insqh %1,%2,%0":"=r" (z):"r" (x),"r" (y))
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#define __get_word(insn,x,ptr) \
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({ \
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long __guu_err; \
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__asm__ __volatile__( \
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"1: "#insn" %0,%2\n" \
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"2:\n" \
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EXC(1b,2b,%0,%1) \
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: "=r"(x), "=r"(__guu_err) \
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: "m"(__m(ptr)), "1"(0)); \
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__guu_err; \
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})
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static inline unsigned short from64to16(unsigned long x)
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{
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/* Using extract instructions is a bit more efficient
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than the original shift/bitmask version. */
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union {
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unsigned long ul;
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unsigned int ui[2];
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unsigned short us[4];
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} in_v, tmp_v, out_v;
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in_v.ul = x;
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tmp_v.ul = (unsigned long) in_v.ui[0] + (unsigned long) in_v.ui[1];
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/* Since the bits of tmp_v.sh[3] are going to always be zero,
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we don't have to bother to add that in. */
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out_v.ul = (unsigned long) tmp_v.us[0] + (unsigned long) tmp_v.us[1]
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+ (unsigned long) tmp_v.us[2];
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/* Similarly, out_v.us[2] is always zero for the final add. */
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return out_v.us[0] + out_v.us[1];
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}
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/*
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* Ok. This isn't fun, but this is the EASY case.
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*/
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static inline unsigned long
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csum_partial_cfu_aligned(const unsigned long __user *src, unsigned long *dst,
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long len)
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{
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unsigned long checksum = ~0U;
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unsigned long carry = 0;
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while (len >= 0) {
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unsigned long word;
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if (__get_word(ldq, word, src))
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return 0;
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checksum += carry;
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src++;
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checksum += word;
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len -= 8;
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carry = checksum < word;
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*dst = word;
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dst++;
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}
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len += 8;
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checksum += carry;
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if (len) {
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unsigned long word, tmp;
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if (__get_word(ldq, word, src))
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return 0;
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tmp = *dst;
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mskql(word, len, word);
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checksum += word;
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mskqh(tmp, len, tmp);
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carry = checksum < word;
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*dst = word | tmp;
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checksum += carry;
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}
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return checksum;
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}
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/*
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* This is even less fun, but this is still reasonably
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* easy.
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*/
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static inline unsigned long
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csum_partial_cfu_dest_aligned(const unsigned long __user *src,
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unsigned long *dst,
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unsigned long soff,
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long len)
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{
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unsigned long first;
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unsigned long word, carry;
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unsigned long lastsrc = 7+len+(unsigned long)src;
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unsigned long checksum = ~0U;
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if (__get_word(ldq_u, first,src))
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return 0;
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carry = 0;
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while (len >= 0) {
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unsigned long second;
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if (__get_word(ldq_u, second, src+1))
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return 0;
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extql(first, soff, word);
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len -= 8;
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src++;
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extqh(second, soff, first);
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checksum += carry;
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word |= first;
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first = second;
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checksum += word;
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*dst = word;
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dst++;
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carry = checksum < word;
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}
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len += 8;
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checksum += carry;
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if (len) {
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unsigned long tmp;
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unsigned long second;
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if (__get_word(ldq_u, second, lastsrc))
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return 0;
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tmp = *dst;
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extql(first, soff, word);
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extqh(second, soff, first);
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word |= first;
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mskql(word, len, word);
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checksum += word;
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mskqh(tmp, len, tmp);
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carry = checksum < word;
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*dst = word | tmp;
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checksum += carry;
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}
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return checksum;
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}
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/*
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* This is slightly less fun than the above..
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*/
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static inline unsigned long
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csum_partial_cfu_src_aligned(const unsigned long __user *src,
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unsigned long *dst,
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unsigned long doff,
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long len,
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unsigned long partial_dest)
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{
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unsigned long carry = 0;
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unsigned long word;
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unsigned long second_dest;
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unsigned long checksum = ~0U;
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mskql(partial_dest, doff, partial_dest);
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while (len >= 0) {
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if (__get_word(ldq, word, src))
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return 0;
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len -= 8;
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insql(word, doff, second_dest);
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checksum += carry;
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stq_u(partial_dest | second_dest, dst);
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src++;
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checksum += word;
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insqh(word, doff, partial_dest);
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carry = checksum < word;
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dst++;
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}
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len += 8;
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if (len) {
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checksum += carry;
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if (__get_word(ldq, word, src))
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return 0;
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mskql(word, len, word);
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len -= 8;
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checksum += word;
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insql(word, doff, second_dest);
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len += doff;
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carry = checksum < word;
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partial_dest |= second_dest;
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if (len >= 0) {
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stq_u(partial_dest, dst);
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if (!len) goto out;
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dst++;
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insqh(word, doff, partial_dest);
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}
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doff = len;
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}
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ldq_u(second_dest, dst);
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mskqh(second_dest, doff, second_dest);
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stq_u(partial_dest | second_dest, dst);
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out:
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checksum += carry;
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return checksum;
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}
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/*
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* This is so totally un-fun that it's frightening. Don't
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* look at this too closely, you'll go blind.
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*/
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static inline unsigned long
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csum_partial_cfu_unaligned(const unsigned long __user * src,
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unsigned long * dst,
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unsigned long soff, unsigned long doff,
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long len, unsigned long partial_dest)
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{
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unsigned long carry = 0;
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unsigned long first;
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unsigned long lastsrc;
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unsigned long checksum = ~0U;
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if (__get_word(ldq_u, first, src))
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return 0;
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lastsrc = 7+len+(unsigned long)src;
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mskql(partial_dest, doff, partial_dest);
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while (len >= 0) {
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unsigned long second, word;
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unsigned long second_dest;
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if (__get_word(ldq_u, second, src+1))
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return 0;
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extql(first, soff, word);
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checksum += carry;
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len -= 8;
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extqh(second, soff, first);
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src++;
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word |= first;
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first = second;
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insql(word, doff, second_dest);
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checksum += word;
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stq_u(partial_dest | second_dest, dst);
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carry = checksum < word;
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insqh(word, doff, partial_dest);
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dst++;
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}
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len += doff;
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checksum += carry;
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if (len >= 0) {
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unsigned long second, word;
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unsigned long second_dest;
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if (__get_word(ldq_u, second, lastsrc))
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return 0;
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extql(first, soff, word);
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extqh(second, soff, first);
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word |= first;
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first = second;
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mskql(word, len-doff, word);
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checksum += word;
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insql(word, doff, second_dest);
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carry = checksum < word;
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stq_u(partial_dest | second_dest, dst);
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if (len) {
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ldq_u(second_dest, dst+1);
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insqh(word, doff, partial_dest);
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mskqh(second_dest, len, second_dest);
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stq_u(partial_dest | second_dest, dst+1);
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}
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checksum += carry;
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} else {
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unsigned long second, word;
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unsigned long second_dest;
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if (__get_word(ldq_u, second, lastsrc))
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return 0;
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extql(first, soff, word);
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extqh(second, soff, first);
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word |= first;
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ldq_u(second_dest, dst);
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mskql(word, len-doff, word);
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checksum += word;
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mskqh(second_dest, len, second_dest);
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carry = checksum < word;
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insql(word, doff, word);
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stq_u(partial_dest | word | second_dest, dst);
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checksum += carry;
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}
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return checksum;
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}
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static __wsum __csum_and_copy(const void __user *src, void *dst, int len)
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{
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unsigned long soff = 7 & (unsigned long) src;
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unsigned long doff = 7 & (unsigned long) dst;
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unsigned long checksum;
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if (!doff) {
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if (!soff)
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checksum = csum_partial_cfu_aligned(
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(const unsigned long __user *) src,
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(unsigned long *) dst, len-8);
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else
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checksum = csum_partial_cfu_dest_aligned(
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(const unsigned long __user *) src,
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(unsigned long *) dst,
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soff, len-8);
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} else {
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unsigned long partial_dest;
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ldq_u(partial_dest, dst);
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if (!soff)
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checksum = csum_partial_cfu_src_aligned(
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(const unsigned long __user *) src,
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(unsigned long *) dst,
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doff, len-8, partial_dest);
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else
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checksum = csum_partial_cfu_unaligned(
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(const unsigned long __user *) src,
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(unsigned long *) dst,
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soff, doff, len-8, partial_dest);
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}
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return (__force __wsum)from64to16 (checksum);
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}
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__wsum
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csum_and_copy_from_user(const void __user *src, void *dst, int len)
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{
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if (!access_ok(src, len))
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return 0;
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return __csum_and_copy(src, dst, len);
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}
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__wsum
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csum_partial_copy_nocheck(const void *src, void *dst, int len)
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{
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return __csum_and_copy((__force const void __user *)src,
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dst, len);
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}
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EXPORT_SYMBOL(csum_partial_copy_nocheck);
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