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_32.h (4682B)


      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef _ASM_X86_CHECKSUM_32_H
      3#define _ASM_X86_CHECKSUM_32_H
      4
      5#include <linux/in6.h>
      6#include <linux/uaccess.h>
      7
      8/*
      9 * computes the checksum of a memory block at buff, length len,
     10 * and adds in "sum" (32-bit)
     11 *
     12 * returns a 32-bit number suitable for feeding into itself
     13 * or csum_tcpudp_magic
     14 *
     15 * this function must be called with even lengths, except
     16 * for the last fragment, which may be odd
     17 *
     18 * it's best to have buff aligned on a 32-bit boundary
     19 */
     20asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
     21
     22/*
     23 * the same as csum_partial, but copies from src while it
     24 * checksums, and handles user-space pointer exceptions correctly, when needed.
     25 *
     26 * here even more important to align src and dst on a 32-bit (or even
     27 * better 64-bit) boundary
     28 */
     29
     30asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
     31
     32/*
     33 *	Note: when you get a NULL pointer exception here this means someone
     34 *	passed in an incorrect kernel address to one of these functions.
     35 *
     36 *	If you use these functions directly please don't forget the
     37 *	access_ok().
     38 */
     39static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
     40{
     41	return csum_partial_copy_generic(src, dst, len);
     42}
     43
     44static inline __wsum csum_and_copy_from_user(const void __user *src,
     45					     void *dst, int len)
     46{
     47	__wsum ret;
     48
     49	might_sleep();
     50	if (!user_access_begin(src, len))
     51		return 0;
     52	ret = csum_partial_copy_generic((__force void *)src, dst, len);
     53	user_access_end();
     54
     55	return ret;
     56}
     57
     58/*
     59 *	This is a version of ip_compute_csum() optimized for IP headers,
     60 *	which always checksum on 4 octet boundaries.
     61 *
     62 *	By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
     63 *	Arnt Gulbrandsen.
     64 */
     65static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
     66{
     67	unsigned int sum;
     68
     69	asm volatile("movl (%1), %0	;\n"
     70		     "subl $4, %2	;\n"
     71		     "jbe 2f		;\n"
     72		     "addl 4(%1), %0	;\n"
     73		     "adcl 8(%1), %0	;\n"
     74		     "adcl 12(%1), %0;\n"
     75		     "1:	adcl 16(%1), %0	;\n"
     76		     "lea 4(%1), %1	;\n"
     77		     "decl %2	;\n"
     78		     "jne 1b		;\n"
     79		     "adcl $0, %0	;\n"
     80		     "movl %0, %2	;\n"
     81		     "shrl $16, %0	;\n"
     82		     "addw %w2, %w0	;\n"
     83		     "adcl $0, %0	;\n"
     84		     "notl %0	;\n"
     85		     "2:		;\n"
     86	/* Since the input registers which are loaded with iph and ihl
     87	   are modified, we must also specify them as outputs, or gcc
     88	   will assume they contain their original values. */
     89		     : "=r" (sum), "=r" (iph), "=r" (ihl)
     90		     : "1" (iph), "2" (ihl)
     91		     : "memory");
     92	return (__force __sum16)sum;
     93}
     94
     95/*
     96 *	Fold a partial checksum
     97 */
     98
     99static inline __sum16 csum_fold(__wsum sum)
    100{
    101	asm("addl %1, %0		;\n"
    102	    "adcl $0xffff, %0	;\n"
    103	    : "=r" (sum)
    104	    : "r" ((__force u32)sum << 16),
    105	      "0" ((__force u32)sum & 0xffff0000));
    106	return (__force __sum16)(~(__force u32)sum >> 16);
    107}
    108
    109static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
    110					__u32 len, __u8 proto,
    111					__wsum sum)
    112{
    113	asm("addl %1, %0	;\n"
    114	    "adcl %2, %0	;\n"
    115	    "adcl %3, %0	;\n"
    116	    "adcl $0, %0	;\n"
    117	    : "=r" (sum)
    118	    : "g" (daddr), "g"(saddr),
    119	      "g" ((len + proto) << 8), "0" (sum));
    120	return sum;
    121}
    122
    123/*
    124 * computes the checksum of the TCP/UDP pseudo-header
    125 * returns a 16-bit checksum, already complemented
    126 */
    127static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
    128					__u32 len, __u8 proto,
    129					__wsum sum)
    130{
    131	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
    132}
    133
    134/*
    135 * this routine is used for miscellaneous IP-like checksums, mainly
    136 * in icmp.c
    137 */
    138
    139static inline __sum16 ip_compute_csum(const void *buff, int len)
    140{
    141    return csum_fold(csum_partial(buff, len, 0));
    142}
    143
    144#define _HAVE_ARCH_IPV6_CSUM
    145static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
    146				      const struct in6_addr *daddr,
    147				      __u32 len, __u8 proto, __wsum sum)
    148{
    149	asm("addl 0(%1), %0	;\n"
    150	    "adcl 4(%1), %0	;\n"
    151	    "adcl 8(%1), %0	;\n"
    152	    "adcl 12(%1), %0	;\n"
    153	    "adcl 0(%2), %0	;\n"
    154	    "adcl 4(%2), %0	;\n"
    155	    "adcl 8(%2), %0	;\n"
    156	    "adcl 12(%2), %0	;\n"
    157	    "adcl %3, %0	;\n"
    158	    "adcl %4, %0	;\n"
    159	    "adcl $0, %0	;\n"
    160	    : "=&r" (sum)
    161	    : "r" (saddr), "r" (daddr),
    162	      "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
    163	    : "memory");
    164
    165	return csum_fold(sum);
    166}
    167
    168/*
    169 *	Copy and checksum to user
    170 */
    171static inline __wsum csum_and_copy_to_user(const void *src,
    172					   void __user *dst,
    173					   int len)
    174{
    175	__wsum ret;
    176
    177	might_sleep();
    178	if (!user_access_begin(dst, len))
    179		return 0;
    180
    181	ret = csum_partial_copy_generic(src, (__force void *)dst, len);
    182	user_access_end();
    183	return ret;
    184}
    185
    186#endif /* _ASM_X86_CHECKSUM_32_H */