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96d4f267e4
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
385 lines
8.9 KiB
C
385 lines
8.9 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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#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_user_u(x,ptr) \
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({ \
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long __guu_err; \
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__asm__ __volatile__( \
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"1: ldq_u %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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#define __put_user_u(x,ptr) \
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({ \
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long __puu_err; \
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__asm__ __volatile__( \
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"1: stq_u %2,%1\n" \
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"2:\n" \
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EXC(1b,2b,$31,%0) \
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: "=r"(__puu_err) \
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: "m"(__m(addr)), "rJ"(x), "0"(0)); \
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__puu_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, unsigned long checksum,
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int *errp)
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{
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unsigned long carry = 0;
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int err = 0;
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while (len >= 0) {
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unsigned long word;
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err |= __get_user(word, src);
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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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err |= __get_user(word, src);
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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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if (err && errp) *errp = err;
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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, unsigned long checksum,
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int *errp)
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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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int err = 0;
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err |= __get_user_u(first,src);
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carry = 0;
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while (len >= 0) {
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unsigned long second;
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err |= __get_user_u(second, src+1);
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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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err |= __get_user_u(second, lastsrc);
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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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if (err && errp) *errp = err;
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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, unsigned long checksum,
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unsigned long partial_dest,
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int *errp)
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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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int err = 0;
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mskql(partial_dest, doff, partial_dest);
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while (len >= 0) {
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err |= __get_user(word, src);
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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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err |= __get_user(word, src);
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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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if (err && errp) *errp = err;
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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 checksum,
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unsigned long partial_dest,
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int *errp)
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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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int err = 0;
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err |= __get_user_u(first, src);
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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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err |= __get_user_u(second, src+1);
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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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err |= __get_user_u(second, lastsrc);
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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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err |= __get_user_u(second, lastsrc);
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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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if (err && errp) *errp = err;
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return checksum;
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}
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__wsum
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csum_partial_copy_from_user(const void __user *src, void *dst, int len,
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__wsum sum, int *errp)
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{
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unsigned long checksum = (__force u32) sum;
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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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if (len) {
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if (!access_ok(src, len)) {
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if (errp) *errp = -EFAULT;
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memset(dst, 0, len);
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return sum;
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}
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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,
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len-8, checksum, errp);
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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, checksum, errp);
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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, checksum,
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partial_dest, errp);
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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, checksum,
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partial_dest, errp);
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}
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checksum = from64to16 (checksum);
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}
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return (__force __wsum)checksum;
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}
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EXPORT_SYMBOL(csum_partial_copy_from_user);
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__wsum
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csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
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{
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__wsum checksum;
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mm_segment_t oldfs = get_fs();
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set_fs(KERNEL_DS);
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checksum = csum_partial_copy_from_user((__force const void __user *)src,
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dst, len, sum, NULL);
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set_fs(oldfs);
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return checksum;
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}
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EXPORT_SYMBOL(csum_partial_copy_nocheck);
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