Gitiles
Code Review Sign In
gerrit-public.fairphone.software / kernel / msm-5.4 / 16a9602158861687c78b6de6dc6a79e6e8a9136f / . / arch / s390 / net / bpf_jit.S
blob: 7e45d13816c183e46962e75c3dc4817d72d5b223 [file] [log] [blame]
Martin Schwidefskyc10302e2012-07-31 16:23:59 +0200[diff] [blame]1/*
2 * BPF Jit compiler for s390, help functions.
3 *
4 * Copyright IBM Corp. 2012
5 *
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
7 */
8#include <linux/linkage.h>
9
10/*
11 * Calling convention:
12 * registers %r2, %r6-%r8, %r10-%r11, %r13, %r15 are call saved
13 * %r2: skb pointer
14 * %r3: offset parameter
15 * %r5: BPF A accumulator
16 * %r8: return address
17 * %r9: save register for skb pointer
18 * %r10: skb->data
19 * %r11: skb->len - skb->data_len (headlen)
20 * %r12: BPF X accumulator
21 *
22 * skb_copy_bits takes 4 parameters:
23 * %r2 = skb pointer
24 * %r3 = offset into skb data
25 * %r4 = length to copy
26 * %r5 = pointer to temp buffer
27 */
28#define SKBDATA %r8
29
30 /* A = *(u32 *) (skb->data+K+X) */
31ENTRY(sk_load_word_ind)
32 ar %r3,%r12 # offset += X
33 bmr %r8 # < 0 -> return with cc
34
35 /* A = *(u32 *) (skb->data+K) */
36ENTRY(sk_load_word)
37 llgfr %r1,%r3 # extend offset
38 ahi %r3,4 # offset + 4
39 clr %r11,%r3 # hlen <= offset + 4 ?
40 jl sk_load_word_slow
41 l %r5,0(%r1,%r10) # get word from skb
42 xr %r1,%r1 # set cc to zero
43 br %r8
44
45sk_load_word_slow:
46 lgr %r9,%r2 # save %r2
47 lhi %r4,4 # 4 bytes
48 la %r5,160(%r15) # pointer to temp buffer
49 brasl %r14,skb_copy_bits # get data from skb
50 l %r5,160(%r15) # load result from temp buffer
51 ltgr %r2,%r2 # set cc to (%r2 != 0)
52 lgr %r2,%r9 # restore %r2
53 br %r8
54
55 /* A = *(u16 *) (skb->data+K+X) */
56ENTRY(sk_load_half_ind)
57 ar %r3,%r12 # offset += X
58 bmr %r8 # < 0 -> return with cc
59
60 /* A = *(u16 *) (skb->data+K) */
61ENTRY(sk_load_half)
62 llgfr %r1,%r3 # extend offset
63 ahi %r3,2 # offset + 2
64 clr %r11,%r3 # hlen <= offset + 2 ?
65 jl sk_load_half_slow
66 llgh %r5,0(%r1,%r10) # get half from skb
67 xr %r1,%r1 # set cc to zero
68 br %r8
69
70sk_load_half_slow:
71 lgr %r9,%r2 # save %r2
72 lhi %r4,2 # 2 bytes
73 la %r5,162(%r15) # pointer to temp buffer
74 brasl %r14,skb_copy_bits # get data from skb
75 xc 160(2,%r15),160(%r15)
76 l %r5,160(%r15) # load result from temp buffer
77 ltgr %r2,%r2 # set cc to (%r2 != 0)
78 lgr %r2,%r9 # restore %r2
79 br %r8
80
81 /* A = *(u8 *) (skb->data+K+X) */
82ENTRY(sk_load_byte_ind)
83 ar %r3,%r12 # offset += X
84 bmr %r8 # < 0 -> return with cc
85
86 /* A = *(u8 *) (skb->data+K) */
87ENTRY(sk_load_byte)
88 llgfr %r1,%r3 # extend offset
89 clr %r11,%r3 # hlen < offset ?
90 jle sk_load_byte_slow
91 lhi %r5,0
92 ic %r5,0(%r1,%r10) # get byte from skb
93 xr %r1,%r1 # set cc to zero
94 br %r8
95
96sk_load_byte_slow:
97 lgr %r9,%r2 # save %r2
98 lhi %r4,1 # 1 bytes
99 la %r5,163(%r15) # pointer to temp buffer
100 brasl %r14,skb_copy_bits # get data from skb
101 xc 160(3,%r15),160(%r15)
102 l %r5,160(%r15) # load result from temp buffer
103 ltgr %r2,%r2 # set cc to (%r2 != 0)
104 lgr %r2,%r9 # restore %r2
105 br %r8
106
107 /* A = (*(u8 *)(skb->data+K) & 0xf) << 2 */
108ENTRY(sk_load_byte_msh)
109 llgfr %r1,%r3 # extend offset
110 clr %r11,%r3 # hlen < offset ?
111 jle sk_load_byte_slow
112 lhi %r12,0
113 ic %r12,0(%r1,%r10) # get byte from skb
114 nill %r12,0x0f
115 sll %r12,2
116 xr %r1,%r1 # set cc to zero
117 br %r8
118
119sk_load_byte_msh_slow:
120 lgr %r9,%r2 # save %r2
121 lhi %r4,2 # 2 bytes
122 la %r5,162(%r15) # pointer to temp buffer
123 brasl %r14,skb_copy_bits # get data from skb
124 xc 160(3,%r15),160(%r15)
125 l %r12,160(%r15) # load result from temp buffer
126 nill %r12,0x0f
127 sll %r12,2
128 ltgr %r2,%r2 # set cc to (%r2 != 0)
129 lgr %r2,%r9 # restore %r2
130 br %r8