Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* Copyright 2002,2003 Andi Kleen, SuSE Labs. |
| 2 | * Subject to the GNU Public License v.2 |
| 3 | * |
| 4 | * Wrappers of assembly checksum functions for x86-64. |
| 5 | */ |
| 6 | |
| 7 | #include <asm/checksum.h> |
| 8 | #include <linux/module.h> |
| 9 | |
| 10 | /** |
| 11 | * csum_partial_copy_from_user - Copy and checksum from user space. |
| 12 | * @src: source address (user space) |
| 13 | * @dst: destination address |
| 14 | * @len: number of bytes to be copied. |
| 15 | * @isum: initial sum that is added into the result (32bit unfolded) |
| 16 | * @errp: set to -EFAULT for an bad source address. |
| 17 | * |
| 18 | * Returns an 32bit unfolded checksum of the buffer. |
| 19 | * src and dst are best aligned to 64bits. |
| 20 | */ |
| 21 | unsigned int |
| 22 | csum_partial_copy_from_user(const unsigned char __user *src, unsigned char *dst, |
| 23 | int len, unsigned int isum, int *errp) |
| 24 | { |
| 25 | might_sleep(); |
| 26 | *errp = 0; |
| 27 | if (likely(access_ok(VERIFY_READ,src, len))) { |
| 28 | /* Why 6, not 7? To handle odd addresses aligned we |
| 29 | would need to do considerable complications to fix the |
| 30 | checksum which is defined as an 16bit accumulator. The |
| 31 | fix alignment code is primarily for performance |
| 32 | compatibility with 32bit and that will handle odd |
| 33 | addresses slowly too. */ |
| 34 | if (unlikely((unsigned long)src & 6)) { |
| 35 | while (((unsigned long)src & 6) && len >= 2) { |
| 36 | __u16 val16; |
| 37 | *errp = __get_user(val16, (__u16 __user *)src); |
| 38 | if (*errp) |
| 39 | return isum; |
| 40 | *(__u16 *)dst = val16; |
| 41 | isum = add32_with_carry(isum, val16); |
| 42 | src += 2; |
| 43 | dst += 2; |
| 44 | len -= 2; |
| 45 | } |
| 46 | } |
| 47 | isum = csum_partial_copy_generic((__force void *)src,dst,len,isum,errp,NULL); |
| 48 | if (likely(*errp == 0)) |
| 49 | return isum; |
| 50 | } |
| 51 | *errp = -EFAULT; |
| 52 | memset(dst,0,len); |
| 53 | return isum; |
| 54 | } |
| 55 | |
| 56 | EXPORT_SYMBOL(csum_partial_copy_from_user); |
| 57 | |
| 58 | /** |
| 59 | * csum_partial_copy_to_user - Copy and checksum to user space. |
| 60 | * @src: source address |
| 61 | * @dst: destination address (user space) |
| 62 | * @len: number of bytes to be copied. |
| 63 | * @isum: initial sum that is added into the result (32bit unfolded) |
| 64 | * @errp: set to -EFAULT for an bad destination address. |
| 65 | * |
| 66 | * Returns an 32bit unfolded checksum of the buffer. |
| 67 | * src and dst are best aligned to 64bits. |
| 68 | */ |
| 69 | unsigned int |
| 70 | csum_partial_copy_to_user(unsigned const char *src, unsigned char __user *dst, |
| 71 | int len, unsigned int isum, int *errp) |
| 72 | { |
| 73 | might_sleep(); |
| 74 | if (unlikely(!access_ok(VERIFY_WRITE, dst, len))) { |
| 75 | *errp = -EFAULT; |
| 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | if (unlikely((unsigned long)dst & 6)) { |
| 80 | while (((unsigned long)dst & 6) && len >= 2) { |
| 81 | __u16 val16 = *(__u16 *)src; |
| 82 | isum = add32_with_carry(isum, val16); |
| 83 | *errp = __put_user(val16, (__u16 __user *)dst); |
| 84 | if (*errp) |
| 85 | return isum; |
| 86 | src += 2; |
| 87 | dst += 2; |
| 88 | len -= 2; |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | *errp = 0; |
| 93 | return csum_partial_copy_generic(src, (void __force *)dst,len,isum,NULL,errp); |
| 94 | } |
| 95 | |
| 96 | EXPORT_SYMBOL(csum_partial_copy_to_user); |
| 97 | |
| 98 | /** |
| 99 | * csum_partial_copy_nocheck - Copy and checksum. |
| 100 | * @src: source address |
| 101 | * @dst: destination address |
| 102 | * @len: number of bytes to be copied. |
| 103 | * @isum: initial sum that is added into the result (32bit unfolded) |
| 104 | * |
| 105 | * Returns an 32bit unfolded checksum of the buffer. |
| 106 | */ |
| 107 | unsigned int |
| 108 | csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst, int len, unsigned int sum) |
| 109 | { |
| 110 | return csum_partial_copy_generic(src,dst,len,sum,NULL,NULL); |
| 111 | } |
| 112 | |
| 113 | unsigned short csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, |
| 114 | __u32 len, unsigned short proto, unsigned int sum) |
| 115 | { |
| 116 | __u64 rest, sum64; |
| 117 | |
| 118 | rest = (__u64)htonl(len) + (__u64)htons(proto) + (__u64)sum; |
| 119 | asm(" addq (%[saddr]),%[sum]\n" |
| 120 | " adcq 8(%[saddr]),%[sum]\n" |
| 121 | " adcq (%[daddr]),%[sum]\n" |
| 122 | " adcq 8(%[daddr]),%[sum]\n" |
| 123 | " adcq $0,%[sum]\n" |
| 124 | : [sum] "=r" (sum64) |
| 125 | : "[sum]" (rest),[saddr] "r" (saddr), [daddr] "r" (daddr)); |
| 126 | return csum_fold(add32_with_carry(sum64 & 0xffffffff, sum64>>32)); |
| 127 | } |
| 128 | |
| 129 | EXPORT_SYMBOL(csum_ipv6_magic); |