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 #endif /* __ASSEMBLY__ */
20 
21 /*
22  * Stackframe layout (packed stack):
23  *
24  *				    ^ high
25  *	      +---------------+     |
26  *	      | old backchain |     |
27  *	      +---------------+     |
28  *	      |   r15 - r6    |     |
29  *	      +---------------+     |
30  *	      | 4 byte align  |     |
31  *	      | tail_call_cnt |     |
32  * BFP	   -> +===============+     |
33  *	      |		      |     |
34  *	      |   BPF stack   |     |
35  *	      |		      |     |
36  * R15+160 -> +---------------+     |
37  *	      | new backchain |     |
38  * R15+152 -> +---------------+     |
39  *	      | + 152 byte SA |     |
40  * R15	   -> +---------------+     + low
41  *
42  * We get 160 bytes stack space from calling function, but only use
43  * 12 * 8 byte for old backchain, r15..r6, and tail_call_cnt.
44  *
45  * The stack size used by the BPF program ("BPF stack" above) is passed
46  * via "aux->stack_depth".
47  */
48 #define STK_SPACE_ADD	(160)
49 #define STK_160_UNUSED	(160 - 12 * 8)
50 #define STK_OFF		(STK_SPACE_ADD - STK_160_UNUSED)
51 
52 #define STK_OFF_R6	(160 - 11 * 8)	/* Offset of r6 on stack */
53 #define STK_OFF_TCCNT	(160 - 12 * 8)	/* Offset of tail_call_cnt on stack */
54 
55 #endif /* __ARCH_S390_NET_BPF_JIT_H */
56