xref: /linux/arch/s390/net/bpf_jit.h (revision fd639726bf15fca8ee1a00dce8e0096d0ad9bd18)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * BPF Jit compiler defines
4  *
5  * Copyright IBM Corp. 2012,2015
6  *
7  * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
8  *	      Michael Holzheu <holzheu@linux.vnet.ibm.com>
9  */
10 
11 #ifndef __ARCH_S390_NET_BPF_JIT_H
12 #define __ARCH_S390_NET_BPF_JIT_H
13 
14 #ifndef __ASSEMBLY__
15 
16 #include <linux/filter.h>
17 #include <linux/types.h>
18 
19 extern u8 sk_load_word_pos[], sk_load_half_pos[], sk_load_byte_pos[];
20 extern u8 sk_load_word[], sk_load_half[], sk_load_byte[];
21 
22 #endif /* __ASSEMBLY__ */
23 
24 /*
25  * Stackframe layout (packed stack):
26  *
27  *				    ^ high
28  *	      +---------------+     |
29  *	      | old backchain |     |
30  *	      +---------------+     |
31  *	      |   r15 - r6    |     |
32  *	      +---------------+     |
33  *	      | 4 byte align  |     |
34  *	      | tail_call_cnt |     |
35  * BFP	   -> +===============+     |
36  *	      |		      |     |
37  *	      |   BPF stack   |     |
38  *	      |		      |     |
39  *	      +---------------+     |
40  *	      | 8 byte skbp   |     |
41  * R15+176 -> +---------------+     |
42  *	      | 8 byte hlen   |     |
43  * R15+168 -> +---------------+     |
44  *	      | 4 byte align  |     |
45  *	      +---------------+     |
46  *	      | 4 byte temp   |     |
47  *	      | for bpf_jit.S |     |
48  * R15+160 -> +---------------+     |
49  *	      | new backchain |     |
50  * R15+152 -> +---------------+     |
51  *	      | + 152 byte SA |     |
52  * R15	   -> +---------------+     + low
53  *
54  * We get 160 bytes stack space from calling function, but only use
55  * 12 * 8 byte for old backchain, r15..r6, and tail_call_cnt.
56  *
57  * The stack size used by the BPF program ("BPF stack" above) is passed
58  * via "aux->stack_depth".
59  */
60 #define STK_SPACE_ADD (8 + 8 + 4 + 4 + 160)
61 #define STK_160_UNUSED	(160 - 12 * 8)
62 #define STK_OFF		(STK_SPACE_ADD - STK_160_UNUSED)
63 #define STK_OFF_TMP	160	/* Offset of tmp buffer on stack */
64 #define STK_OFF_HLEN	168	/* Offset of SKB header length on stack */
65 #define STK_OFF_SKBP	176	/* Offset of SKB pointer on stack */
66 
67 #define STK_OFF_R6	(160 - 11 * 8)	/* Offset of r6 on stack */
68 #define STK_OFF_TCCNT	(160 - 12 * 8)	/* Offset of tail_call_cnt on stack */
69 
70 /* Offset to skip condition code check */
71 #define OFF_OK		4
72 
73 #endif /* __ARCH_S390_NET_BPF_JIT_H */
74