arch/s390/net/bpf_jit.h

   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 */