summaryrefslogtreecommitdiff
path: root/arch/s390/net/bpf_jit.S
blob: ba44c9f5534633a2da3133714f6b018ba6a69545 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
/*
 * BPF Jit compiler for s390, help functions.
 *
 * Copyright IBM Corp. 2012
 *
 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 */
#include <linux/linkage.h>

/*
 * Calling convention:
 * registers %r2, %r6-%r8, %r10-%r11, %r13, %r15 are call saved
 *   %r2: skb pointer
 *   %r3: offset parameter
 *   %r5: BPF A accumulator
 *   %r8: return address
 *   %r9: save register for skb pointer
 *   %r10: skb->data
 *   %r11: skb->len - skb->data_len (headlen)
 *   %r12: BPF X accumulator
 *
 * skb_copy_bits takes 4 parameters:
 *   %r2 = skb pointer
 *   %r3 = offset into skb data
 *   %r4 = pointer to temp buffer
 *   %r5 = length to copy
 */
#define SKBDATA	%r8

	/* A = *(u32 *) (skb->data+K+X) */
ENTRY(sk_load_word_ind)
	ar	%r3,%r12		# offset += X
	bmr	%r8			# < 0 -> return with cc

	/* A = *(u32 *) (skb->data+K) */
ENTRY(sk_load_word)
	llgfr	%r1,%r3			# extend offset
	ahi	%r3,4			# offset + 4
	clr	%r11,%r3		# hlen <= offset + 4 ?
	jl	sk_load_word_slow
	l	%r5,0(%r1,%r10)		# get word from skb
	xr	%r1,%r1			# set cc to zero
	br	%r8

sk_load_word_slow:
	lgr	%r9,%r2			# save %r2
	lgr	%r3,%r1			# offset
	la	%r4,160(%r15)		# pointer to temp buffer
	lghi	%r5,4			# 4 bytes
	brasl	%r14,skb_copy_bits	# get data from skb
	l	%r5,160(%r15)		# load result from temp buffer
	ltgr	%r2,%r2			# set cc to (%r2 != 0)
	lgr	%r2,%r9			# restore %r2
	br	%r8

	/* A = *(u16 *) (skb->data+K+X) */
ENTRY(sk_load_half_ind)
	ar	%r3,%r12		# offset += X
	bmr	%r8			# < 0 -> return with cc

	/* A = *(u16 *) (skb->data+K) */
ENTRY(sk_load_half)
	llgfr	%r1,%r3			# extend offset
	ahi	%r3,2			# offset + 2
	clr	%r11,%r3		# hlen <= offset + 2 ?
	jl	sk_load_half_slow
	llgh	%r5,0(%r1,%r10)		# get half from skb
	xr	%r1,%r1			# set cc to zero
	br	%r8

sk_load_half_slow:
	lgr	%r9,%r2			# save %r2
	lgr	%r3,%r1			# offset
	la	%r4,162(%r15)		# pointer to temp buffer
	lghi	%r5,2			# 2 bytes
	brasl	%r14,skb_copy_bits	# get data from skb
	xc	160(2,%r15),160(%r15)
	l	%r5,160(%r15)		# load result from temp buffer
	ltgr	%r2,%r2			# set cc to (%r2 != 0)
	lgr	%r2,%r9			# restore %r2
	br	%r8

	/* A = *(u8 *) (skb->data+K+X) */
ENTRY(sk_load_byte_ind)
	ar	%r3,%r12		# offset += X
	bmr	%r8			# < 0 -> return with cc

	/* A = *(u8 *) (skb->data+K) */
ENTRY(sk_load_byte)
	llgfr	%r1,%r3			# extend offset
	clr	%r11,%r3		# hlen < offset ?
	jle	sk_load_byte_slow
	lhi	%r5,0
	ic	%r5,0(%r1,%r10)		# get byte from skb
	xr	%r1,%r1			# set cc to zero
	br	%r8

sk_load_byte_slow:
	lgr	%r9,%r2			# save %r2
	lgr	%r3,%r1			# offset
	la	%r4,163(%r15)		# pointer to temp buffer
	lghi	%r5,1			# 1 byte
	brasl	%r14,skb_copy_bits	# get data from skb
	xc	160(3,%r15),160(%r15)
	l	%r5,160(%r15)		# load result from temp buffer
	ltgr	%r2,%r2			# set cc to (%r2 != 0)
	lgr	%r2,%r9			# restore %r2
	br	%r8

	/* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
ENTRY(sk_load_byte_msh)
	llgfr	%r1,%r3			# extend offset
	clr	%r11,%r3		# hlen < offset ?
	jle	sk_load_byte_msh_slow
	lhi	%r12,0
	ic	%r12,0(%r1,%r10)	# get byte from skb
	nill	%r12,0x0f
	sll	%r12,2
	xr	%r1,%r1			# set cc to zero
	br	%r8

sk_load_byte_msh_slow:
	lgr	%r9,%r2			# save %r2
	lgr	%r3,%r1			# offset
	la	%r4,163(%r15)		# pointer to temp buffer
	lghi	%r5,1			# 1 byte
	brasl	%r14,skb_copy_bits	# get data from skb
	xc	160(3,%r15),160(%r15)
	l	%r12,160(%r15)		# load result from temp buffer
	nill	%r12,0x0f
	sll	%r12,2
	ltgr	%r2,%r2			# set cc to (%r2 != 0)
	lgr	%r2,%r9			# restore %r2
	br	%r8