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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2002, 2003 Andi Kleen, SuSE Labs.
*
* Wrappers of assembly checksum functions for x86-64.
*/
#include <asm/checksum.h>
#include <linux/export.h>
#include <linux/uaccess.h>
#include <asm/smap.h>
/**
* csum_and_copy_from_user - Copy and checksum from user space.
* @src: source address (user space)
* @dst: destination address
* @len: number of bytes to be copied.
* @isum: initial sum that is added into the result (32bit unfolded)
* @errp: set to -EFAULT for an bad source address.
*
* Returns an 32bit unfolded checksum of the buffer.
* src and dst are best aligned to 64bits.
*/
__wsum
csum_and_copy_from_user(const void __user *src, void *dst,
int len)
{
int err = 0;
__wsum isum = ~0U;
might_sleep();
if (!user_access_begin(src, len))
return 0;
/*
* Why 6, not 7? To handle odd addresses aligned we
* would need to do considerable complications to fix the
* checksum which is defined as an 16bit accumulator. The
* fix alignment code is primarily for performance
* compatibility with 32bit and that will handle odd
* addresses slowly too.
*/
if (unlikely((unsigned long)src & 6)) {
while (((unsigned long)src & 6) && len >= 2) {
__u16 val16;
unsafe_get_user(val16, (const __u16 __user *)src, out);
*(__u16 *)dst = val16;
isum = (__force __wsum)add32_with_carry(
(__force unsigned)isum, val16);
src += 2;
dst += 2;
len -= 2;
}
}
isum = csum_partial_copy_generic((__force const void *)src,
dst, len, isum, &err, NULL);
user_access_end();
if (unlikely(err))
isum = 0;
return isum;
out:
user_access_end();
return 0;
}
EXPORT_SYMBOL(csum_and_copy_from_user);
/**
* csum_and_copy_to_user - Copy and checksum to user space.
* @src: source address
* @dst: destination address (user space)
* @len: number of bytes to be copied.
* @isum: initial sum that is added into the result (32bit unfolded)
* @errp: set to -EFAULT for an bad destination address.
*
* Returns an 32bit unfolded checksum of the buffer.
* src and dst are best aligned to 64bits.
*/
__wsum
csum_and_copy_to_user(const void *src, void __user *dst,
int len)
{
__wsum ret, isum = ~0U;
int err = 0;
might_sleep();
if (!user_access_begin(dst, len))
return 0;
if (unlikely((unsigned long)dst & 6)) {
while (((unsigned long)dst & 6) && len >= 2) {
__u16 val16 = *(__u16 *)src;
isum = (__force __wsum)add32_with_carry(
(__force unsigned)isum, val16);
unsafe_put_user(val16, (__u16 __user *)dst, out);
src += 2;
dst += 2;
len -= 2;
}
}
ret = csum_partial_copy_generic(src, (void __force *)dst,
len, isum, NULL, &err);
user_access_end();
return err ? 0 : ret;
out:
user_access_end();
return 0;
}
EXPORT_SYMBOL(csum_and_copy_to_user);
/**
* csum_partial_copy_nocheck - Copy and checksum.
* @src: source address
* @dst: destination address
* @len: number of bytes to be copied.
* @sum: initial sum that is added into the result (32bit unfolded)
*
* Returns an 32bit unfolded checksum of the buffer.
*/
__wsum
csum_partial_copy_nocheck(const void *src, void *dst, int len)
{
return csum_partial_copy_generic(src, dst, len, 0, NULL, NULL);
}
EXPORT_SYMBOL(csum_partial_copy_nocheck);
__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
const struct in6_addr *daddr,
__u32 len, __u8 proto, __wsum sum)
{
__u64 rest, sum64;
rest = (__force __u64)htonl(len) + (__force __u64)htons(proto) +
(__force __u64)sum;
asm(" addq (%[saddr]),%[sum]\n"
" adcq 8(%[saddr]),%[sum]\n"
" adcq (%[daddr]),%[sum]\n"
" adcq 8(%[daddr]),%[sum]\n"
" adcq $0,%[sum]\n"
: [sum] "=r" (sum64)
: "[sum]" (rest), [saddr] "r" (saddr), [daddr] "r" (daddr));
return csum_fold(
(__force __wsum)add32_with_carry(sum64 & 0xffffffff, sum64>>32));
}
EXPORT_SYMBOL(csum_ipv6_magic);
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