Line data    Source code

       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
      24          18 : csum_and_copy_from_user(const void __user *src, void *dst, int len)
      25             : {
      26          18 :         __wsum sum;
      27             : 
      28          18 :         might_sleep();
      29          18 :         if (!user_access_begin(src, len))
      30             :                 return 0;
      31          18 :         sum = csum_partial_copy_generic((__force const void *)src, dst, len);
      32          18 :         user_access_end();
      33          18 :         return sum;
      34             : }
      35             : EXPORT_SYMBOL(csum_and_copy_from_user);
      36             : 
      37             : /**
      38             :  * csum_and_copy_to_user - Copy and checksum to user space.
      39             :  * @src: source address
      40             :  * @dst: destination address (user space)
      41             :  * @len: number of bytes to be copied.
      42             :  * @isum: initial sum that is added into the result (32bit unfolded)
      43             :  * @errp: set to -EFAULT for an bad destination address.
      44             :  *
      45             :  * Returns an 32bit unfolded checksum of the buffer.
      46             :  * src and dst are best aligned to 64bits.
      47             :  */
      48             : __wsum
      49           0 : csum_and_copy_to_user(const void *src, void __user *dst, int len)
      50             : {
      51           0 :         __wsum sum;
      52             : 
      53           0 :         might_sleep();
      54           0 :         if (!user_access_begin(dst, len))
      55             :                 return 0;
      56           0 :         sum = csum_partial_copy_generic(src, (void __force *)dst, len);
      57           0 :         user_access_end();
      58           0 :         return sum;
      59             : }
      60             : EXPORT_SYMBOL(csum_and_copy_to_user);
      61             : 
      62             : /**
      63             :  * csum_partial_copy_nocheck - Copy and checksum.
      64             :  * @src: source address
      65             :  * @dst: destination address
      66             :  * @len: number of bytes to be copied.
      67             :  * @sum: initial sum that is added into the result (32bit unfolded)
      68             :  *
      69             :  * Returns an 32bit unfolded checksum of the buffer.
      70             :  */
      71             : __wsum
      72           0 : csum_partial_copy_nocheck(const void *src, void *dst, int len)
      73             : {
      74           0 :         return csum_partial_copy_generic(src, dst, len);
      75             : }
      76             : EXPORT_SYMBOL(csum_partial_copy_nocheck);
      77             : 
      78           0 : __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
      79             :                         const struct in6_addr *daddr,
      80             :                         __u32 len, __u8 proto, __wsum sum)
      81             : {
      82           0 :         __u64 rest, sum64;
      83             : 
      84           0 :         rest = (__force __u64)htonl(len) + (__force __u64)htons(proto) +
      85           0 :                 (__force __u64)sum;
      86             : 
      87           0 :         asm("      addq (%[saddr]),%[sum]\n"
      88             :             "      adcq 8(%[saddr]),%[sum]\n"
      89             :             "      adcq (%[daddr]),%[sum]\n"
      90             :             "      adcq 8(%[daddr]),%[sum]\n"
      91             :             "      adcq $0,%[sum]\n"
      92             : 
      93             :             : [sum] "=r" (sum64)
      94             :             : "[sum]" (rest), [saddr] "r" (saddr), [daddr] "r" (daddr));
      95             : 
      96           0 :         return csum_fold(
      97           0 :                (__force __wsum)add32_with_carry(sum64 & 0xffffffff, sum64>>32));
      98             : }
      99             : EXPORT_SYMBOL(csum_ipv6_magic);