deps/lightrec/disassembler.c

   1 /*
   2  * Copyright (C) 2014-2020 Paul Cercueil <paul@crapouillou.net>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  */
  14
  15 #include "config.h"
  16
  17 #if ENABLE_DISASSEMBLER
  18 #include <dis-asm.h>
  19 #endif
  20 #include <stdbool.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23
  24 #include "debug.h"
  25 #include "disassembler.h"
  26 #include "lightrec-private.h"
  27 #include "memmanager.h"
  28
  29 static bool is_unconditional_jump(const struct opcode *op)
  30 {
  31         switch (op->i.op) {
  32         case OP_SPECIAL:
  33                 return op->r.op == OP_SPECIAL_JR || op->r.op == OP_SPECIAL_JALR;
  34         case OP_J:
  35         case OP_JAL:
  36                 return true;
  37         case OP_BEQ:
  38         case OP_BLEZ:
  39                 return op->i.rs == op->i.rt;
  40         case OP_REGIMM:
  41                 return (op->r.rt == OP_REGIMM_BGEZ ||
  42                         op->r.rt == OP_REGIMM_BGEZAL) && op->i.rs == 0;
  43         default:
  44                 return false;
  45         }
  46 }
  47
  48 static bool is_syscall(const struct opcode *op)
  49 {
  50         return (op->i.op == OP_SPECIAL && (op->r.op == OP_SPECIAL_SYSCALL ||
  51                                            op->r.op == OP_SPECIAL_BREAK)) ||
  52                 (op->i.op == OP_CP0 && (op->r.rs == OP_CP0_MTC0 ||
  53                                         op->r.rs == OP_CP0_CTC0) &&
  54                  (op->r.rd == 12 || op->r.rd == 13));
  55 }
  56
  57 void lightrec_free_opcode_list(struct lightrec_state *state, struct opcode *list)
  58 {
  59         struct opcode *next;
  60
  61         while (list) {
  62                 next = list->next;
  63                 lightrec_free(state, MEM_FOR_IR, sizeof(*list), list);
  64                 list = next;
  65         }
  66 }
  67
  68 struct opcode * lightrec_disassemble(struct lightrec_state *state,
  69                                      const u32 *src, unsigned int *len)
  70 {
  71         struct opcode *head = NULL;
  72         bool stop_next = false;
  73         struct opcode *curr, *last;
  74         unsigned int i;
  75
  76         for (i = 0, last = NULL; ; i++, last = curr) {
  77                 curr = lightrec_calloc(state, MEM_FOR_IR, sizeof(*curr));
  78                 if (!curr) {
  79                         pr_err("Unable to allocate memory\n");
  80                         lightrec_free_opcode_list(state, head);
  81                         return NULL;
  82                 }
  83
  84                 if (!last)
  85                         head = curr;
  86                 else
  87                         last->next = curr;
  88
  89                 /* TODO: Take care of endianness */
  90                 curr->opcode = LE32TOH(*src++);
  91                 curr->offset = i;
  92
  93                 /* NOTE: The block disassembly ends after the opcode that
  94                  * follows an unconditional jump (delay slot) */
  95                 if (stop_next || is_syscall(curr))
  96                         break;
  97                 else if (is_unconditional_jump(curr))
  98                         stop_next = true;
  99         }
 100
 101         if (len)
 102                 *len = (i + 1) * sizeof(u32);
 103
 104         return head;
 105 }
 106
 107 unsigned int lightrec_cycles_of_opcode(union code code)
 108 {
 109         switch (code.i.op) {
 110         case OP_META_REG_UNLOAD:
 111         case OP_META_SYNC:
 112                 return 0;
 113         default:
 114                 return 2;
 115         }
 116 }
 117
 118 #if ENABLE_DISASSEMBLER
 119 void lightrec_print_disassembly(const struct block *block,
 120                                 const u32 *code, unsigned int length)
 121 {
 122         struct disassemble_info info;
 123         unsigned int i;
 124
 125         memset(&info, 0, sizeof(info));
 126         init_disassemble_info(&info, stdout, (fprintf_ftype) fprintf);
 127
 128         info.buffer = (bfd_byte *) code;
 129         info.buffer_vma = (bfd_vma)(uintptr_t) code;
 130         info.buffer_length = length;
 131         info.flavour = bfd_target_unknown_flavour;
 132         info.arch = bfd_arch_mips;
 133         info.mach = bfd_mach_mips3000;
 134         disassemble_init_for_target(&info);
 135
 136         for (i = 0; i < length; i += 4) {
 137                 void print_insn_little_mips(bfd_vma, struct disassemble_info *);
 138                 putc('\t', stdout);
 139                 print_insn_little_mips((bfd_vma)(uintptr_t) code++, &info);
 140                 putc('\n', stdout);
 141         }
 142 }
 143 #endif