sim/bpf/mloop.in

   1 # Simulator main loop for eBPF. -*- C -*-
   2 #
   3 # Copyright (C) 2020-2021 Free Software Foundation, Inc.
   4 #
   5 # This file is part of the GNU Simulators.
   6 #
   7 # This program is free software; you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation; either version 3 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19
  20 # Syntax:
  21 # /bin/sh mloop.in command
  22 #
  23 # Command is one of:
  24 #
  25 # init
  26 # support
  27 # extract-{simple,scache,pbb}
  28 # {full,fast}-exec-{simple,scache,pbb}
  29 #
  30 # A target need only provide a "full" version of one of simple,scache,pbb.
  31 # If the target wants it can also provide a fast version of same, or if
  32 # the slow (full featured) version is `simple', then the fast version can be
  33 # one of scache/pbb.
  34 # A target can't provide more than this.
  35 # However for illustration's sake this file provides examples of all.
  36
  37 # ??? After a few more ports are done, revisit.
  38 # Will eventually need to machine generate a lot of this.
  39
  40 case "x$1" in
  41
  42 xsupport)
  43
  44 cat <<EOF
  45
  46 static INLINE const IDESC *
  47 extract (SIM_CPU *current_cpu, PCADDR pc, CGEN_INSN_WORD insn,
  48          ARGBUF *abuf, int fast_p)
  49 {
  50   const IDESC *id = @prefix@_decode (current_cpu, pc, insn, abuf);
  51   @prefix@_fill_argbuf (current_cpu, abuf, id, pc, fast_p);
  52   if (!fast_p)
  53     {
  54       int trace_p = PC_IN_TRACE_RANGE_P (current_cpu, pc);
  55       int profile_p = PC_IN_PROFILE_RANGE_P (current_cpu, pc);
  56       @prefix@_fill_argbuf_tp (current_cpu, abuf, trace_p, profile_p);
  57     }
  58   return id;
  59 }
  60
  61 static INLINE SEM_PC
  62 execute (SIM_CPU *current_cpu, SCACHE *sc, int fast_p)
  63 {
  64   SEM_PC vpc;
  65
  66   if (fast_p)
  67       vpc = (*sc->argbuf.semantic.sem_fast) (current_cpu, sc);
  68   else
  69     {
  70       ARGBUF *abuf = &sc->argbuf;
  71       const IDESC *idesc = abuf->idesc;
  72       const CGEN_INSN *idata = idesc->idata;
  73       int virtual_p = 0;
  74
  75       if (! virtual_p)
  76         {
  77           /* FIXME: call x-before */
  78           if (ARGBUF_PROFILE_P (abuf))
  79             PROFILE_COUNT_INSN (current_cpu, abuf->addr, idesc->num);
  80           /* FIXME: Later make cover macros: PROFILE_INSN_{INIT,FINI}.  */
  81           if (PROFILE_MODEL_P (current_cpu)
  82               && ARGBUF_PROFILE_P (abuf))
  83             @cpu@_model_insn_before (current_cpu, 1 /*first_p*/);
  84           CGEN_TRACE_INSN_INIT (current_cpu, abuf, 1);
  85           CGEN_TRACE_INSN (current_cpu, idata,
  86                       (const struct argbuf *) abuf, abuf->addr);
  87         }
  88       vpc = (*sc->argbuf.semantic.sem_full) (current_cpu, sc);
  89       if (! virtual_p)
  90         {
  91           /* FIXME: call x-after */
  92           if (PROFILE_MODEL_P (current_cpu)
  93               && ARGBUF_PROFILE_P (abuf))
  94             {
  95               int cycles;
  96
  97               cycles = (*idesc->timing->model_fn) (current_cpu, sc);
  98               @cpu@_model_insn_after (current_cpu, 1 /*last_p*/, cycles);
  99             }
 100           CGEN_TRACE_INSN_FINI (current_cpu, abuf, 1);
 101         }
 102     }
 103
 104   return vpc;
 105 }
 106
 107 EOF
 108
 109 ;;
 110
 111 xinit)
 112
 113 # Nothing needed.
 114
 115 ;;
 116
 117 xextract-scache)
 118
 119 cat <<EOF
 120 {
 121
 122   UDI insn = GETIMEMUDI (current_cpu, vpc);
 123
 124   if (CURRENT_TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
 125     {
 126       UHI off16;
 127       USI imm32;
 128
 129       /* eBPF instructions are little-endian, but GETIMEMUDI reads according
 130          to target byte order. Swap to little-endian. */
 131       insn = SWAP_8 (insn);
 132
 133       /* But, the imm32 and offset16 fields within instructions follow target
 134          byte order. Swap those fields back. */
 135       off16 = (UHI) ((insn & 0x00000000ffff0000) >> 16);
 136       imm32 = (USI) ((insn & 0xffffffff00000000) >> 32);
 137       off16 = SWAP_2 (off16);
 138       imm32 = SWAP_4 (imm32);
 139
 140       insn = (((UDI) imm32) << 32) | (((UDI) off16) << 16) | (insn & 0xffff);
 141     }
 142
 143   extract (current_cpu, vpc, insn, SEM_ARGBUF (sc), FAST_P);
 144
 145   //XXX  SEM_SKIP_COMPILE (current_cpu, sc, 1);
 146 }
 147 EOF
 148
 149 ;;
 150
 151 xfull-exec-* | xfast-exec-*)
 152
 153 # Inputs: current_cpu, vpc, sc, FAST_P
 154 # Outputs: vpc
 155 # vpc is the virtual program counter.
 156
 157 cat <<EOF
 158    vpc = execute (current_cpu, sc, FAST_P);
 159 EOF
 160
 161 ;;
 162
 163 *)
 164   echo "Invalid argument to mainloop.in: $1" >&2
 165   exit 1
 166   ;;
 167
 168 esac