cpu/bpf.opc

   1 /* EBPF opcode support.  -*- c -*-
   2
   3    Copyright (C) 2019 Free Software Foundation, Inc.
   4
   5    Contributed by Oracle, Inc.
   6
   7    This file is part of the GNU Binutils and of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  22    MA 02110-1301, USA.  */
  23
  24 /*
  25    Each section is delimited with start and end markers.
  26
  27    <arch>-opc.h additions use: "-- opc.h"
  28    <arch>-opc.c additions use: "-- opc.c"
  29    <arch>-asm.c additions use: "-- asm.c"
  30    <arch>-dis.c additions use: "-- dis.c"
  31    <arch>-ibd.h additions use: "-- ibd.h".  */
  32 \f
  33 /* -- opc.h */
  34
  35 #undef CGEN_DIS_HASH_SIZE
  36 #define CGEN_DIS_HASH_SIZE 1
  37
  38 #undef CGEN_DIS_HASH
  39 #define CGEN_DIS_HASH(buffer, value) 0
  40
  41 /* Allows reason codes to be output when assembler errors occur.  */
  42 #define CGEN_VERBOSE_ASSEMBLER_ERRORS
  43
  44 #define CGEN_VALIDATE_INSN_SUPPORTED
  45 extern int bpf_cgen_insn_supported (CGEN_CPU_DESC, const CGEN_INSN *);
  46
  47 \f
  48 /* -- opc.c */
  49 \f
  50 /* -- asm.c */
  51
  52 /* Parse a signed 64-bit immediate.  */
  53
  54 static const char *
  55 parse_imm64 (CGEN_CPU_DESC cd,
  56              const char **strp,
  57              int opindex,
  58              int64_t *valuep)
  59 {
  60   bfd_vma value;
  61   enum cgen_parse_operand_result result;
  62   const char *errmsg;
  63
  64   errmsg = (* cd->parse_operand_fn)
  65     (cd, CGEN_PARSE_OPERAND_INTEGER, strp, opindex, BFD_RELOC_NONE,
  66      &result, &value);
  67   if (!errmsg)
  68     *valuep = value;
  69
  70   return errmsg;
  71 }
  72
  73 /* Endianness size operands are integer immediates whose values can be
  74    16, 32 or 64.  */
  75
  76 static const char *
  77 parse_endsize (CGEN_CPU_DESC cd,
  78                const char **strp,
  79                int opindex,
  80                unsigned long *valuep)
  81 {
  82   const char *errmsg;
  83
  84   errmsg = cgen_parse_unsigned_integer (cd, strp, opindex, valuep);
  85   if (errmsg)
  86     return errmsg;
  87
  88   switch (*valuep)
  89     {
  90     case 16:
  91     case 32:
  92     case 64:
  93       break;
  94     default:
  95       return _("expected 16, 32 or 64 in");
  96     }
  97
  98   return NULL;
  99 }
 100
 101 /* Special check to ensure that the right instruction variant is used
 102    for the given endianness induced by the ISA selected in the CPU.
 103    See bpf.cpu for a discussion on how eBPF is really two instruction
 104    sets.  */
 105
 106 int
 107 bpf_cgen_insn_supported (CGEN_CPU_DESC cd, const CGEN_INSN *insn)
 108 {
 109   CGEN_BITSET isas = CGEN_INSN_BITSET_ATTR_VALUE (insn, CGEN_INSN_ISA);
 110
 111   return cgen_bitset_intersect_p (&isas, cd->isas);
 112 }
 113
 114 \f
 115 /* -- dis.c */
 116
 117 /* We need to customize the disassembler a bit:
 118    - Use 8 bytes per line by default.
 119 */
 120
 121 #define CGEN_PRINT_INSN bpf_print_insn
 122
 123 static int
 124 bpf_print_insn (CGEN_CPU_DESC cd, bfd_vma pc, disassemble_info *info)
 125 {
 126   bfd_byte buf[CGEN_MAX_INSN_SIZE];
 127   int buflen;
 128   int status;
 129
 130   info->bytes_per_chunk = 1;
 131   info->bytes_per_line = 8;
 132   info->endian_code = BFD_ENDIAN_BIG;
 133
 134   /* Attempt to read the base part of the insn.  */
 135   buflen = cd->base_insn_bitsize / 8;
 136   status = (*info->read_memory_func) (pc, buf, buflen, info);
 137
 138   /* Try again with the minimum part, if min < base.  */
 139   if (status != 0 && (cd->min_insn_bitsize < cd->base_insn_bitsize))
 140     {
 141       buflen = cd->min_insn_bitsize / 8;
 142       status = (*info->read_memory_func) (pc, buf, buflen, info);
 143     }
 144
 145   if (status != 0)
 146     {
 147       (*info->memory_error_func) (status, pc, info);
 148       return -1;
 149     }
 150
 151   return print_insn (cd, pc, info, buf, buflen);
 152 }
 153
 154 /* Signed immediates should be printed in hexadecimal.  */
 155
 156 static void
 157 print_immediate (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 158                  void *dis_info,
 159                  int64_t value,
 160                  unsigned int attrs ATTRIBUTE_UNUSED,
 161                  bfd_vma pc ATTRIBUTE_UNUSED,
 162                  int length ATTRIBUTE_UNUSED)
 163 {
 164   disassemble_info *info = (disassemble_info *) dis_info;
 165
 166   if (value <= 9)
 167     (*info->fprintf_func) (info->stream, "%" PRId64, value);
 168   else
 169     (*info->fprintf_func) (info->stream, "%#" PRIx64, value);
 170
 171   /* This is to avoid -Wunused-function for print_normal.  */
 172   if (0)
 173     print_normal (cd, dis_info, value, attrs, pc, length);
 174 }
 175
 176 /* Endianness bit sizes should be printed in decimal.  */
 177
 178 static void
 179 print_endsize (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 180                void *dis_info,
 181                unsigned long value,
 182                unsigned int attrs ATTRIBUTE_UNUSED,
 183                bfd_vma pc ATTRIBUTE_UNUSED,
 184                int length ATTRIBUTE_UNUSED)
 185 {
 186   disassemble_info *info = (disassemble_info *) dis_info;
 187   (*info->fprintf_func) (info->stream, "%lu", value);
 188 }
 189
 190 \f
 191 /* -- */
 192