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c10302ef MS |
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) */ | |
31 | ENTRY(sk_load_word_ind) | |
32 | ar %r3,%r12 # offset += X | |
33 | bmr %r8 # < 0 -> return with cc | |
34 | ||
35 | /* A = *(u32 *) (skb->data+K) */ | |
36 | ENTRY(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 | ||
45 | sk_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) */ | |
56 | ENTRY(sk_load_half_ind) | |
57 | ar %r3,%r12 # offset += X | |
58 | bmr %r8 # < 0 -> return with cc | |
59 | ||
60 | /* A = *(u16 *) (skb->data+K) */ | |
61 | ENTRY(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 | ||
70 | sk_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) */ | |
82 | ENTRY(sk_load_byte_ind) | |
83 | ar %r3,%r12 # offset += X | |
84 | bmr %r8 # < 0 -> return with cc | |
85 | ||
86 | /* A = *(u8 *) (skb->data+K) */ | |
87 | ENTRY(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 | ||
96 | sk_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 */ | |
108 | ENTRY(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 | ||
119 | sk_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 |