Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/arc/include/asm/checksum.h
26481 views
1
/* SPDX-License-Identifier: GPL-2.0-only */

2
/*

3
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)

4
 *

5
 * Joern Rennecke  <[email protected]>: Jan 2012

6
 *  -Insn Scheduling improvements to csum core routines.

7
 *      = csum_fold( ) largely derived from ARM version.

8
 *      = ip_fast_cum( ) to have module scheduling

9
 *  -gcc 4.4.x broke networking. Alias analysis needed to be primed.

10
 *   worked around by adding memory clobber to ip_fast_csum( )

11
 *

12
 * vineetg: May 2010

13
 *  -Rewrote ip_fast_cscum( ) and csum_fold( ) with fast inline asm

14
 */

15


16
#ifndef _ASM_ARC_CHECKSUM_H

17
#define _ASM_ARC_CHECKSUM_H

18


19
/*

20
 *	Fold a partial checksum

21
 *

22
 *  The 2 swords comprising the 32bit sum are added, any carry to 16th bit

23
 *  added back and final sword result inverted.

24
 */

25
static inline __sum16 csum_fold(__wsum s)

26
{

27
	unsigned int r = s << 16 | s >> 16;	/* ror */

28
	s = ~s;

29
	s -= r;

30
	return s >> 16;

31
}

32


33
/*

34
 *	This is a version of ip_compute_csum() optimized for IP headers,

35
 *	which always checksum on 4 octet boundaries.

36
 */

37
static inline __sum16

38
ip_fast_csum(const void *iph, unsigned int ihl)

39
{

40
	const void *ptr = iph;

41
	unsigned int tmp, tmp2, sum;

42


43
	__asm__(

44
	"	ld.ab  %0, [%3, 4]		\n"

45
	"	ld.ab  %2, [%3, 4]		\n"

46
	"	sub    %1, %4, 2		\n"

47
	"	lsr.f  lp_count, %1, 1		\n"

48
	"	bcc    0f			\n"

49
	"	add.f  %0, %0, %2		\n"

50
	"	ld.ab  %2, [%3, 4]		\n"

51
	"0:	lp     1f			\n"

52
	"	ld.ab  %1, [%3, 4]		\n"

53
	"	adc.f  %0, %0, %2		\n"

54
	"	ld.ab  %2, [%3, 4]		\n"

55
	"	adc.f  %0, %0, %1		\n"

56
	"1:	adc.f  %0, %0, %2		\n"

57
	"	add.cs %0,%0,1			\n"

58
	: "=&r"(sum), "=r"(tmp), "=&r"(tmp2), "+&r" (ptr)

59
	: "r"(ihl)

60
	: "cc", "lp_count", "memory");

61


62
	return csum_fold(sum);

63
}

64


65
/*

66
 * TCP pseudo Header is 12 bytes:

67
 * SA [4], DA [4], zeroes [1], Proto[1], TCP Seg(hdr+data) Len [2]

68
 */

69
static inline __wsum

70
csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,

71
		   __u8 proto, __wsum sum)

72
{

73
	__asm__ __volatile__(

74
	"	add.f %0, %0, %1	\n"

75
	"	adc.f %0, %0, %2	\n"

76
	"	adc.f %0, %0, %3	\n"

77
	"	adc.f %0, %0, %4	\n"

78
	"	adc   %0, %0, 0		\n"

79
	: "+&r"(sum)

80
	: "r"(saddr), "r"(daddr),

81
#ifdef CONFIG_CPU_BIG_ENDIAN

82
	  "r"(len),

83
#else

84
	  "r"(len << 8),

85
#endif

86
	  "r"(htons(proto))

87
	: "cc");

88


89
	return sum;

90
}

91


92
#define csum_fold csum_fold

93
#define ip_fast_csum ip_fast_csum

94
#define csum_tcpudp_nofold csum_tcpudp_nofold

95


96
#include <asm-generic/checksum.h>

97


98
#endif /* _ASM_ARC_CHECKSUM_H */

99


100