sim/rx/load.c

   1 /* load.c --- loading object files into the RX simulator.
   2
   3 Copyright (C) 2005-2021 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
  22 #include "config.h"
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26
  27 #include "bfd.h"
  28 #include "cpu.h"
  29 #include "mem.h"
  30 #include "load.h"
  31 #include "elf-bfd.h"
  32
  33 /* Helper function for invoking a GDB-specified printf.  */
  34 static void
  35 xprintf (host_callback *callback, const char *fmt, ...)
  36 {
  37   va_list ap;
  38
  39   va_start (ap, fmt);
  40
  41   (*callback->vprintf_filtered) (callback, fmt, ap);
  42
  43   va_end (ap);
  44 }
  45
  46 /* Given a file offset, look up the section name.  */
  47 static const char *
  48 find_section_name_by_offset (bfd *abfd, file_ptr filepos)
  49 {
  50   asection *s;
  51
  52   for (s = abfd->sections; s; s = s->next)
  53     if (s->filepos == filepos)
  54       return bfd_section_name (s);
  55
  56   return "(unknown)";
  57 }
  58
  59 /* A note about endianness and swapping...
  60
  61    The RX chip is CISC-like in that the opcodes are variable length
  62    and are read as a stream of bytes.  However, the chip itself shares
  63    the code prefetch block with the data fetch block, so when it's
  64    configured for big endian mode, the memory fetched for opcodes is
  65    word-swapped.  To compensate for this, the ELF file has the code
  66    sections pre-swapped.  Our BFD knows this, and for the convenience
  67    of all the other tools, hides this swapping at a very low level.
  68    I.e.  it swaps words on the way out and on the way back in.
  69
  70    Fortunately the iovector routines are unaffected by this, so we
  71    can use them to read in the segments directly, without having
  72    to worry about byte swapping anything.
  73
  74    However, our opcode decoder and disassemblers need to swap the data
  75    after reading it from the chip memory, just like the chip does.
  76    All in all, the code words are swapped four times between the
  77    assembler and our decoder.
  78
  79    If the chip is running in little-endian mode, no swapping is done
  80    anywhere.  Note also that the *operands* within opcodes are always
  81    encoded in little-endian format.  */
  82
  83 void
  84 rx_load (bfd *prog, host_callback *callback)
  85 {
  86   unsigned long highest_addr_loaded = 0;
  87   Elf_Internal_Phdr * phdrs;
  88   long sizeof_phdrs;
  89   int num_headers;
  90   int i;
  91
  92   rx_big_endian = bfd_big_endian (prog);
  93
  94   /* Note we load by ELF program header not by BFD sections.
  95      This is because BFD sections get their information from
  96      the ELF section structure, which only includes a VMA value
  97      and not an LMA value.  */
  98   sizeof_phdrs = bfd_get_elf_phdr_upper_bound (prog);
  99   if (sizeof_phdrs == 0)
 100     {
 101       fprintf (stderr, "Failed to get size of program headers\n");
 102       return;
 103     }
 104   phdrs = malloc (sizeof_phdrs);
 105   if (phdrs == NULL)
 106     {
 107       fprintf (stderr, "Failed allocate memory to hold program headers\n");
 108       return;
 109     }
 110   num_headers = bfd_get_elf_phdrs (prog, phdrs);
 111   if (num_headers < 1)
 112     {
 113       fprintf (stderr, "Failed to read program headers\n");
 114       return;
 115     }
 116
 117   for (i = 0; i < num_headers; i++)
 118     {
 119       Elf_Internal_Phdr * p = phdrs + i;
 120       char *buf;
 121       bfd_vma size;
 122       bfd_vma base;
 123       file_ptr offset;
 124
 125       size = p->p_filesz;
 126       if (size <= 0)
 127         continue;
 128
 129       base = p->p_paddr;
 130       if (verbose > 1)
 131         fprintf (stderr, "[load segment: lma=%08x vma=%08x size=%08x]\n",
 132                  (int) base, (int) p->p_vaddr, (int) size);
 133       if (callback)
 134         xprintf (callback,
 135                  "Loading section %s, size %#lx lma %08lx vma %08lx\n",
 136                  find_section_name_by_offset (prog, p->p_offset),
 137                  size, base, p->p_vaddr);
 138
 139       buf = malloc (size);
 140       if (buf == NULL)
 141         {
 142           fprintf (stderr, "Failed to allocate buffer to hold program segment\n");
 143           continue;
 144         }
 145
 146       offset = p->p_offset;
 147       if (bfd_seek (prog, offset, SEEK_SET) != 0)
 148         {
 149           fprintf (stderr, "Failed to seek to offset %lx\n", (long) offset);
 150           continue;
 151         }
 152       if (bfd_bread (buf, size, prog) != size)
 153         {
 154           fprintf (stderr, "Failed to read %lx bytes\n", (long) size);
 155           continue;
 156         }
 157
 158       mem_put_blk (base, buf, size);
 159       free (buf);
 160       if (highest_addr_loaded < base + size - 1 && size >= 4)
 161         highest_addr_loaded = base + size - 1;
 162     }
 163
 164   free (phdrs);
 165
 166   regs.r_pc = prog->start_address;
 167
 168   if (strcmp (bfd_get_target (prog), "srec") == 0
 169       || regs.r_pc == 0)
 170     {
 171       regs.r_pc = mem_get_si (0xfffffffc);
 172       heaptop = heapbottom = 0;
 173     }
 174
 175   reset_decoder ();
 176
 177   if (verbose > 1)
 178     fprintf (stderr, "[start pc=%08x %s]\n",
 179              (unsigned int) regs.r_pc,
 180              rx_big_endian ? "BE" : "LE");
 181 }