arch/x86/lib/csum-wrappers_64.c

   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  *
  18  * Returns an 32bit unfolded checksum of the buffer.
  19  * src and dst are best aligned to 64bits.
  20  */
  21 __wsum
  22 csum_and_copy_from_user(const void __user *src, void *dst, int len)
  23 {
  24         __wsum sum;
  25
  26         might_sleep();
  27         if (!user_access_begin(src, len))
  28                 return 0;
  29         sum = csum_partial_copy_generic((__force const void *)src, dst, len);
  30         user_access_end();
  31         return sum;
  32 }
  33
  34 /**
  35  * csum_and_copy_to_user - Copy and checksum to user space.
  36  * @src: source address
  37  * @dst: destination address (user space)
  38  * @len: number of bytes to be copied.
  39  *
  40  * Returns an 32bit unfolded checksum of the buffer.
  41  * src and dst are best aligned to 64bits.
  42  */
  43 __wsum
  44 csum_and_copy_to_user(const void *src, void __user *dst, int len)
  45 {
  46         __wsum sum;
  47
  48         might_sleep();
  49         if (!user_access_begin(dst, len))
  50                 return 0;
  51         sum = csum_partial_copy_generic(src, (void __force *)dst, len);
  52         user_access_end();
  53         return sum;
  54 }
  55
  56 /**
  57  * csum_partial_copy_nocheck - Copy and checksum.
  58  * @src: source address
  59  * @dst: destination address
  60  * @len: number of bytes to be copied.
  61  *
  62  * Returns an 32bit unfolded checksum of the buffer.
  63  */
  64 __wsum
  65 csum_partial_copy_nocheck(const void *src, void *dst, int len)
  66 {
  67         return csum_partial_copy_generic(src, dst, len);
  68 }
  69 EXPORT_SYMBOL(csum_partial_copy_nocheck);
  70
  71 __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
  72                         const struct in6_addr *daddr,
  73                         __u32 len, __u8 proto, __wsum sum)
  74 {
  75         __u64 rest, sum64;
  76
  77         rest = (__force __u64)htonl(len) + (__force __u64)htons(proto) +
  78                 (__force __u64)sum;
  79
  80         asm("   addq (%[saddr]),%[sum]\n"
  81             "   adcq 8(%[saddr]),%[sum]\n"
  82             "   adcq (%[daddr]),%[sum]\n"
  83             "   adcq 8(%[daddr]),%[sum]\n"
  84             "   adcq $0,%[sum]\n"
  85
  86             : [sum] "=r" (sum64)
  87             : "[sum]" (rest), [saddr] "r" (saddr), [daddr] "r" (daddr));
  88
  89         return csum_fold(
  90                (__force __wsum)add32_with_carry(sum64 & 0xffffffff, sum64>>32));
  91 }
  92 EXPORT_SYMBOL(csum_ipv6_magic);