mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
123 lines
2.9 KiB
123 lines
2.9 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* arch/x86_64/lib/csum-partial.c |
|
* |
|
* This file contains network checksum routines that are better done |
|
* in an architecture-specific manner due to speed. |
|
*/ |
|
|
|
#include <linux/compiler.h> |
|
#include <linux/export.h> |
|
#include <asm/checksum.h> |
|
#include <asm/word-at-a-time.h> |
|
|
|
static inline unsigned short from32to16(unsigned a) |
|
{ |
|
unsigned short b = a >> 16; |
|
asm("addw %w2,%w0\n\t" |
|
"adcw $0,%w0\n" |
|
: "=r" (b) |
|
: "0" (b), "r" (a)); |
|
return b; |
|
} |
|
|
|
/* |
|
* Do a checksum on an arbitrary memory area. |
|
* Returns a 32bit checksum. |
|
* |
|
* This isn't as time critical as it used to be because many NICs |
|
* do hardware checksumming these days. |
|
* |
|
* Still, with CHECKSUM_COMPLETE this is called to compute |
|
* checksums on IPv6 headers (40 bytes) and other small parts. |
|
* it's best to have buff aligned on a 64-bit boundary |
|
*/ |
|
__wsum csum_partial(const void *buff, int len, __wsum sum) |
|
{ |
|
u64 temp64 = (__force u64)sum; |
|
unsigned odd, result; |
|
|
|
odd = 1 & (unsigned long) buff; |
|
if (unlikely(odd)) { |
|
if (unlikely(len == 0)) |
|
return sum; |
|
temp64 = ror32((__force u32)sum, 8); |
|
temp64 += (*(unsigned char *)buff << 8); |
|
len--; |
|
buff++; |
|
} |
|
|
|
while (unlikely(len >= 64)) { |
|
asm("addq 0*8(%[src]),%[res]\n\t" |
|
"adcq 1*8(%[src]),%[res]\n\t" |
|
"adcq 2*8(%[src]),%[res]\n\t" |
|
"adcq 3*8(%[src]),%[res]\n\t" |
|
"adcq 4*8(%[src]),%[res]\n\t" |
|
"adcq 5*8(%[src]),%[res]\n\t" |
|
"adcq 6*8(%[src]),%[res]\n\t" |
|
"adcq 7*8(%[src]),%[res]\n\t" |
|
"adcq $0,%[res]" |
|
: [res] "+r" (temp64) |
|
: [src] "r" (buff) |
|
: "memory"); |
|
buff += 64; |
|
len -= 64; |
|
} |
|
|
|
if (len & 32) { |
|
asm("addq 0*8(%[src]),%[res]\n\t" |
|
"adcq 1*8(%[src]),%[res]\n\t" |
|
"adcq 2*8(%[src]),%[res]\n\t" |
|
"adcq 3*8(%[src]),%[res]\n\t" |
|
"adcq $0,%[res]" |
|
: [res] "+r" (temp64) |
|
: [src] "r" (buff) |
|
: "memory"); |
|
buff += 32; |
|
} |
|
if (len & 16) { |
|
asm("addq 0*8(%[src]),%[res]\n\t" |
|
"adcq 1*8(%[src]),%[res]\n\t" |
|
"adcq $0,%[res]" |
|
: [res] "+r" (temp64) |
|
: [src] "r" (buff) |
|
: "memory"); |
|
buff += 16; |
|
} |
|
if (len & 8) { |
|
asm("addq 0*8(%[src]),%[res]\n\t" |
|
"adcq $0,%[res]" |
|
: [res] "+r" (temp64) |
|
: [src] "r" (buff) |
|
: "memory"); |
|
buff += 8; |
|
} |
|
if (len & 7) { |
|
unsigned int shift = (8 - (len & 7)) * 8; |
|
unsigned long trail; |
|
|
|
trail = (load_unaligned_zeropad(buff) << shift) >> shift; |
|
|
|
asm("addq %[trail],%[res]\n\t" |
|
"adcq $0,%[res]" |
|
: [res] "+r" (temp64) |
|
: [trail] "r" (trail)); |
|
} |
|
result = add32_with_carry(temp64 >> 32, temp64 & 0xffffffff); |
|
if (unlikely(odd)) { |
|
result = from32to16(result); |
|
result = ((result >> 8) & 0xff) | ((result & 0xff) << 8); |
|
} |
|
return (__force __wsum)result; |
|
} |
|
EXPORT_SYMBOL(csum_partial); |
|
|
|
/* |
|
* this routine is used for miscellaneous IP-like checksums, mainly |
|
* in icmp.c |
|
*/ |
|
__sum16 ip_compute_csum(const void *buff, int len) |
|
{ |
|
return csum_fold(csum_partial(buff,len,0)); |
|
} |
|
EXPORT_SYMBOL(ip_compute_csum);
|
|
|