cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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csum-wrappers_64.c (2622B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Copyright 2002, 2003 Andi Kleen, SuSE Labs.
      4 *
      5 * Wrappers of assembly checksum functions for x86-64.
      6 */
      7#include <asm/checksum.h>
      8#include <linux/export.h>
      9#include <linux/uaccess.h>
     10#include <asm/smap.h>
     11
     12/**
     13 * csum_and_copy_from_user - Copy and checksum from user space.
     14 * @src: source address (user space)
     15 * @dst: destination address
     16 * @len: number of bytes to be copied.
     17 * @isum: initial sum that is added into the result (32bit unfolded)
     18 * @errp: set to -EFAULT for an bad source address.
     19 *
     20 * Returns an 32bit unfolded checksum of the buffer.
     21 * src and dst are best aligned to 64bits.
     22 */
     23__wsum
     24csum_and_copy_from_user(const void __user *src, void *dst, int len)
     25{
     26	__wsum sum;
     27
     28	might_sleep();
     29	if (!user_access_begin(src, len))
     30		return 0;
     31	sum = csum_partial_copy_generic((__force const void *)src, dst, len);
     32	user_access_end();
     33	return sum;
     34}
     35
     36/**
     37 * csum_and_copy_to_user - Copy and checksum to user space.
     38 * @src: source address
     39 * @dst: destination address (user space)
     40 * @len: number of bytes to be copied.
     41 * @isum: initial sum that is added into the result (32bit unfolded)
     42 * @errp: set to -EFAULT for an bad destination address.
     43 *
     44 * Returns an 32bit unfolded checksum of the buffer.
     45 * src and dst are best aligned to 64bits.
     46 */
     47__wsum
     48csum_and_copy_to_user(const void *src, void __user *dst, int len)
     49{
     50	__wsum sum;
     51
     52	might_sleep();
     53	if (!user_access_begin(dst, len))
     54		return 0;
     55	sum = csum_partial_copy_generic(src, (void __force *)dst, len);
     56	user_access_end();
     57	return sum;
     58}
     59
     60/**
     61 * csum_partial_copy_nocheck - Copy and checksum.
     62 * @src: source address
     63 * @dst: destination address
     64 * @len: number of bytes to be copied.
     65 * @sum: initial sum that is added into the result (32bit unfolded)
     66 *
     67 * Returns an 32bit unfolded checksum of the buffer.
     68 */
     69__wsum
     70csum_partial_copy_nocheck(const void *src, void *dst, int len)
     71{
     72	return csum_partial_copy_generic(src, dst, len);
     73}
     74EXPORT_SYMBOL(csum_partial_copy_nocheck);
     75
     76__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
     77			const struct in6_addr *daddr,
     78			__u32 len, __u8 proto, __wsum sum)
     79{
     80	__u64 rest, sum64;
     81
     82	rest = (__force __u64)htonl(len) + (__force __u64)htons(proto) +
     83		(__force __u64)sum;
     84
     85	asm("	addq (%[saddr]),%[sum]\n"
     86	    "	adcq 8(%[saddr]),%[sum]\n"
     87	    "	adcq (%[daddr]),%[sum]\n"
     88	    "	adcq 8(%[daddr]),%[sum]\n"
     89	    "	adcq $0,%[sum]\n"
     90
     91	    : [sum] "=r" (sum64)
     92	    : "[sum]" (rest), [saddr] "r" (saddr), [daddr] "r" (daddr));
     93
     94	return csum_fold(
     95	       (__force __wsum)add32_with_carry(sum64 & 0xffffffff, sum64>>32));
     96}
     97EXPORT_SYMBOL(csum_ipv6_magic);