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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checksum.h (2950B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef __UM_CHECKSUM_H
      3#define __UM_CHECKSUM_H
      4
      5#include <linux/string.h>
      6#include <linux/in6.h>
      7#include <linux/uaccess.h>
      8
      9/*
     10 * computes the checksum of a memory block at buff, length len,
     11 * and adds in "sum" (32-bit)
     12 *
     13 * returns a 32-bit number suitable for feeding into itself
     14 * or csum_tcpudp_magic
     15 *
     16 * this function must be called with even lengths, except
     17 * for the last fragment, which may be odd
     18 *
     19 * it's best to have buff aligned on a 32-bit boundary
     20 */
     21extern __wsum csum_partial(const void *buff, int len, __wsum sum);
     22
     23/**
     24 * csum_fold - Fold and invert a 32bit checksum.
     25 * sum: 32bit unfolded sum
     26 *
     27 * Fold a 32bit running checksum to 16bit and invert it. This is usually
     28 * the last step before putting a checksum into a packet.
     29 * Make sure not to mix with 64bit checksums.
     30 */
     31static inline __sum16 csum_fold(__wsum sum)
     32{
     33	__asm__(
     34		"  addl %1,%0\n"
     35		"  adcl $0xffff,%0"
     36		: "=r" (sum)
     37		: "r" ((__force u32)sum << 16),
     38		  "0" ((__force u32)sum & 0xffff0000)
     39	);
     40	return (__force __sum16)(~(__force u32)sum >> 16);
     41}
     42
     43/**
     44 * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
     45 * @saddr: source address
     46 * @daddr: destination address
     47 * @len: length of packet
     48 * @proto: ip protocol of packet
     49 * @sum: initial sum to be added in (32bit unfolded)
     50 *
     51 * Returns the pseudo header checksum the input data. Result is
     52 * 32bit unfolded.
     53 */
     54static inline __wsum
     55csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
     56		  __u8 proto, __wsum sum)
     57{
     58	asm("  addl %1, %0\n"
     59	    "  adcl %2, %0\n"
     60	    "  adcl %3, %0\n"
     61	    "  adcl $0, %0\n"
     62		: "=r" (sum)
     63	    : "g" (daddr), "g" (saddr), "g" ((len + proto) << 8), "0" (sum));
     64	return sum;
     65}
     66
     67/*
     68 * computes the checksum of the TCP/UDP pseudo-header
     69 * returns a 16-bit checksum, already complemented
     70 */
     71static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
     72					__u32 len, __u8 proto,
     73					__wsum sum)
     74{
     75	return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
     76}
     77
     78/**
     79 * ip_fast_csum - Compute the IPv4 header checksum efficiently.
     80 * iph: ipv4 header
     81 * ihl: length of header / 4
     82 */
     83static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
     84{
     85	unsigned int sum;
     86
     87	asm(	"  movl (%1), %0\n"
     88		"  subl $4, %2\n"
     89		"  jbe 2f\n"
     90		"  addl 4(%1), %0\n"
     91		"  adcl 8(%1), %0\n"
     92		"  adcl 12(%1), %0\n"
     93		"1: adcl 16(%1), %0\n"
     94		"  lea 4(%1), %1\n"
     95		"  decl %2\n"
     96		"  jne	1b\n"
     97		"  adcl $0, %0\n"
     98		"  movl %0, %2\n"
     99		"  shrl $16, %0\n"
    100		"  addw %w2, %w0\n"
    101		"  adcl $0, %0\n"
    102		"  notl %0\n"
    103		"2:"
    104	/* Since the input registers which are loaded with iph and ipl
    105	   are modified, we must also specify them as outputs, or gcc
    106	   will assume they contain their original values. */
    107	: "=r" (sum), "=r" (iph), "=r" (ihl)
    108	: "1" (iph), "2" (ihl)
    109	: "memory");
    110	return (__force __sum16)sum;
    111}
    112
    113#ifdef CONFIG_X86_32
    114# include "checksum_32.h"
    115#else
    116# include "checksum_64.h"
    117#endif
    118
    119#endif