sim/rx/load.c

   1 /* load.c --- loading object files into the RX simulator.
   2
   3 Copyright (C) 2005-2022 Free Software Foundation, Inc.
   4 Contributed by Red Hat, Inc.
   5
   6 This file is part of the GNU simulators.
   7
   8 This program is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3 of the License, or
  11 (at your option) any later version.
  12
  13 This program is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 /* This must come before any other includes.  */
  22 #include "defs.h"
  23
  24 #include <stdlib.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27
  28 #include "bfd.h"
  29 #include "cpu.h"
  30 #include "mem.h"
  31 #include "load.h"
  32 #include "elf-bfd.h"
  33
  34 /* Helper function for invoking a GDB-specified printf.  */
  35 static void
  36 xprintf (host_callback *callback, const char *fmt, ...)
  37 {
  38   va_list ap;
  39
  40   va_start (ap, fmt);
  41
  42   (*callback->vprintf_filtered) (callback, fmt, ap);
  43
  44   va_end (ap);
  45 }
  46
  47 /* Given a file offset, look up the section name.  */
  48 static const char *
  49 find_section_name_by_offset (bfd *abfd, file_ptr filepos)
  50 {
  51   asection *s;
  52
  53   for (s = abfd->sections; s; s = s->next)
  54     if (s->filepos == filepos)
  55       return bfd_section_name (s);
  56
  57   return "(unknown)";
  58 }
  59
  60 /* A note about endianness and swapping...
  61
  62    The RX chip is CISC-like in that the opcodes are variable length
  63    and are read as a stream of bytes.  However, the chip itself shares
  64    the code prefetch block with the data fetch block, so when it's
  65    configured for big endian mode, the memory fetched for opcodes is
  66    word-swapped.  To compensate for this, the ELF file has the code
  67    sections pre-swapped.  Our BFD knows this, and for the convenience
  68    of all the other tools, hides this swapping at a very low level.
  69    I.e.  it swaps words on the way out and on the way back in.
  70
  71    Fortunately the iovector routines are unaffected by this, so we
  72    can use them to read in the segments directly, without having
  73    to worry about byte swapping anything.
  74
  75    However, our opcode decoder and disassemblers need to swap the data
  76    after reading it from the chip memory, just like the chip does.
  77    All in all, the code words are swapped four times between the
  78    assembler and our decoder.
  79
  80    If the chip is running in little-endian mode, no swapping is done
  81    anywhere.  Note also that the *operands* within opcodes are always
  82    encoded in little-endian format.  */
  83
  84 void
  85 rx_load (bfd *prog, host_callback *callback)
  86 {
  87   unsigned long highest_addr_loaded = 0;
  88   Elf_Internal_Phdr * phdrs;
  89   long sizeof_phdrs;
  90   int num_headers;
  91   int i;
  92
  93   rx_big_endian = bfd_big_endian (prog);
  94
  95   /* Note we load by ELF program header not by BFD sections.
  96      This is because BFD sections get their information from
  97      the ELF section structure, which only includes a VMA value
  98      and not an LMA value.  */
  99   sizeof_phdrs = bfd_get_elf_phdr_upper_bound (prog);
 100   if (sizeof_phdrs == 0)
 101     {
 102       fprintf (stderr, "Failed to get size of program headers\n");
 103       return;
 104     }
 105   phdrs = malloc (sizeof_phdrs);
 106   if (phdrs == NULL)
 107     {
 108       fprintf (stderr, "Failed allocate memory to hold program headers\n");
 109       return;
 110     }
 111   num_headers = bfd_get_elf_phdrs (prog, phdrs);
 112   if (num_headers < 1)
 113     {
 114       fprintf (stderr, "Failed to read program headers\n");
 115       return;
 116     }
 117
 118   for (i = 0; i < num_headers; i++)
 119     {
 120       Elf_Internal_Phdr * p = phdrs + i;
 121       char *buf;
 122       bfd_vma size;
 123       bfd_vma base;
 124       file_ptr offset;
 125
 126       size = p->p_filesz;
 127       if (size <= 0)
 128         continue;
 129
 130       base = p->p_paddr;
 131       if (verbose > 1)
 132         fprintf (stderr,
 133                  "[load segment: lma=%08" BFD_VMA_FMT "x vma=%08x "
 134                  "size=%08" BFD_VMA_FMT "x]\n",
 135                  base, (int) p->p_vaddr, size);
 136       if (callback)
 137         xprintf (callback,
 138                  "Loading section %s, size %#lx lma %08lx vma %08lx\n",
 139                  find_section_name_by_offset (prog, p->p_offset),
 140                  size, base, p->p_vaddr);
 141
 142       buf = malloc (size);
 143       if (buf == NULL)
 144         {
 145           fprintf (stderr, "Failed to allocate buffer to hold program segment\n");
 146           continue;
 147         }
 148
 149       offset = p->p_offset;
 150       if (bfd_seek (prog, offset, SEEK_SET) != 0)
 151         {
 152           fprintf (stderr, "Failed to seek to offset %lx\n", (long) offset);
 153           continue;
 154         }
 155       if (bfd_bread (buf, size, prog) != size)
 156         {
 157           fprintf (stderr, "Failed to read %" BFD_VMA_FMT "x bytes\n", size);
 158           continue;
 159         }
 160
 161       mem_put_blk (base, buf, size);
 162       free (buf);
 163       if (highest_addr_loaded < base + size - 1 && size >= 4)
 164         highest_addr_loaded = base + size - 1;
 165     }
 166
 167   free (phdrs);
 168
 169   regs.r_pc = prog->start_address;
 170
 171   if (strcmp (bfd_get_target (prog), "srec") == 0
 172       || regs.r_pc == 0)
 173     {
 174       regs.r_pc = mem_get_si (0xfffffffc);
 175       heaptop = heapbottom = 0;
 176     }
 177
 178   reset_decoder ();
 179
 180   if (verbose > 1)
 181     fprintf (stderr, "[start pc=%08x %s]\n",
 182              (unsigned int) regs.r_pc,
 183              rx_big_endian ? "BE" : "LE");
 184 }