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  * @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 csum_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 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 csum_and_copy_to_user(const void *src, void __user *dst, int len)
  50 {
  51         __wsum sum;
  52
  53         might_sleep();
  54         if (!user_access_begin(dst, len))
  55                 return 0;
  56         sum = csum_partial_copy_generic(src, (void __force *)dst, len);
  57         user_access_end();
  58         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 csum_partial_copy_nocheck(const void *src, void *dst, int len)
  73 {
  74         return csum_partial_copy_generic(src, dst, len);
  75 }
  76 EXPORT_SYMBOL(csum_partial_copy_nocheck);
  77
  78 __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
  79                         const struct in6_addr *daddr,
  80                         __u32 len, __u8 proto, __wsum sum)
  81 {
  82         __u64 rest, sum64;
  83
  84         rest = (__force __u64)htonl(len) + (__force __u64)htons(proto) +
  85                 (__force __u64)sum;
  86
  87         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         return csum_fold(
  97                (__force __wsum)add32_with_carry(sum64 & 0xffffffff, sum64>>32));
  98 }
  99 EXPORT_SYMBOL(csum_ipv6_magic);