diff options
Diffstat (limited to 'elf.c')
| -rw-r--r-- | elf.c | 250 |
1 files changed, 250 insertions, 0 deletions
@@ -0,0 +1,250 @@ +/* This file is part of SIS (SPARC/RISCV instruction simulator) + + Copyright (C) 2019 Free Software Foundation, Inc. + Contributed by Jiri Gaisler, Sweden. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +/* Very simple ELF program loader, only tested with RTEMS */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <netinet/in.h> +#include <elf.h> +#include <ctype.h> +#include "sis.h" + +struct elf_file +{ + FILE *fp; + Elf32_Ehdr ehdr; + char *strtab; + int arch; + int cpu; + int be; +}; + +static struct elf_file efile; + +static int +read_elf_header (FILE * fp) +{ + Elf32_Ehdr ehdr; + + fseek (fp, 0, SEEK_SET); + if (fread (&ehdr, sizeof (ehdr), 1, fp) != 1) + { + return (-1); + } + efile.fp = fp; + + if ((ehdr.e_ident[EI_MAG0] != 0x7f) || + strncmp (&ehdr.e_ident[EI_MAG1], "ELF", 3) != 0) + { + return (-1); + } + + if (ehdr.e_ident[EI_DATA] == ELFDATA2MSB) + { + efile.be = 1; + ehdr.e_entry = ntohl (ehdr.e_entry); + ehdr.e_shoff = ntohl (ehdr.e_shoff); + ehdr.e_phoff = ntohl (ehdr.e_phoff); + ehdr.e_phnum = ntohs (ehdr.e_phnum); + ehdr.e_shnum = ntohs (ehdr.e_shnum); + ehdr.e_phentsize = ntohs (ehdr.e_phentsize); + ehdr.e_shentsize = ntohs (ehdr.e_shentsize); + ehdr.e_shstrndx = ntohs (ehdr.e_shstrndx); + ehdr.e_machine = ntohs (ehdr.e_machine); + } + + switch (ehdr.e_machine) + { + case EM_SPARC: + if (sis_verbose) + printf ("SPARC executable\n"); + efile.arch = CPU_ERC32; + efile.cpu = CPU_ERC32; + break; + case EM_RISCV: + if (sis_verbose) + printf ("RISCV executable\n"); + efile.arch = CPU_RISCV; + efile.cpu = CPU_RISCV; + break; + default: + printf ("Unknown architecture (%d)\n", ehdr.e_machine); + return (-1); + } + + if (ehdr.e_ident[EI_CLASS] != 1) + { + printf ("Only 32-bit ELF supported!\n"); + return (-1); + } + efile.ehdr = ehdr; + ebase.cpu = efile.cpu; + return (ehdr.e_entry); +} + +static int +read_elf_body () +{ + Elf32_Ehdr ehdr = efile.ehdr; + Elf32_Shdr sh, ssh; + Elf32_Phdr ph[16]; + char *strtab; + char *mem; + uint32 *memw, i, j, k, vaddr; + int be = efile.be; + FILE *fp = efile.fp; + + fseek (fp, ehdr.e_shoff + ((ehdr.e_shstrndx) * ehdr.e_shentsize), SEEK_SET); + if (fread (&ssh, sizeof (ssh), 1, fp) != 1) + { + return (-1); + } + + /* endian swap if big-endian target */ + if (be) + { + ssh.sh_name = ntohl (ssh.sh_name); + ssh.sh_type = ntohl (ssh.sh_type); + ssh.sh_offset = ntohl (ssh.sh_offset); + ssh.sh_size = ntohl (ssh.sh_size); + } + strtab = (char *) malloc (ssh.sh_size); + fseek (fp, ssh.sh_offset, SEEK_SET); + if (fread (strtab, ssh.sh_size, 1, fp) != 1) + { + return (-1); + } + + for (i = 0; i < ehdr.e_phnum; i++) + { + fseek (fp, ehdr.e_phoff + (i * ehdr.e_phentsize), SEEK_SET); + if (fread (&ph[i], ehdr.e_phentsize, 1, fp) != 1) + { + return (-1); + } + if (be) + { + ph[i].p_type = ntohl (ph[i].p_type); + ph[i].p_offset = ntohl (ph[i].p_offset); + ph[i].p_vaddr = ntohl (ph[i].p_vaddr); + ph[i].p_paddr = ntohl (ph[i].p_paddr); + ph[i].p_filesz = ntohl (ph[i].p_filesz); + ph[i].p_memsz = ntohl (ph[i].p_memsz); + } + } + + for (i = 1; i < ehdr.e_shnum; i++) + { + fseek (fp, ehdr.e_shoff + (i * ehdr.e_shentsize), SEEK_SET); + if (fread (&sh, sizeof (sh), 1, fp) != 1) + { + return (-1); + } + if (be) + { + sh.sh_name = ntohl (sh.sh_name); + sh.sh_addr = ntohl (sh.sh_addr); + sh.sh_size = ntohl (sh.sh_size); + sh.sh_type = ntohl (sh.sh_type); + sh.sh_offset = ntohl (sh.sh_offset); + sh.sh_flags = ntohl (sh.sh_flags); + } + + if ((sh.sh_type != SHT_NOBITS) && (sh.sh_size) + && (sh.sh_flags & SHF_ALLOC)) + { + for (k = 0; k < ehdr.e_phnum; k++) + { + if ((sh.sh_addr >= ph[k].p_vaddr) && + ((sh.sh_addr + sh.sh_size) <= + (ph[k].p_vaddr + ph[k].p_filesz))) + { + vaddr = sh.sh_addr; + sh.sh_addr = sh.sh_addr - ph[k].p_vaddr + ph[k].p_paddr; + break; + } + } + if (sis_verbose) + printf ("section: %s at 0x%x, size %d bytes\n", + &strtab[sh.sh_name], sh.sh_addr, sh.sh_size); + mem = calloc (sh.sh_size / 4 + 1, 4); + if (mem != NULL) + { + if ((sh.sh_type == SHT_PROGBITS) + || (sh.sh_type == SHT_INIT_ARRAY) + || (sh.sh_type == SHT_FINI_ARRAY)) + { + fseek (fp, sh.sh_offset, SEEK_SET); + if (fread (mem, sh.sh_size, 1, fp) != 1) + { + return (-1); + } + memw = (unsigned int *) mem; + if (be) + for (j = 0; j < (sh.sh_size) / 4 + 1; j++) + memw[j] = ntohl (memw[j]); + ms->sis_memory_write (sh.sh_addr, mem, + (sh.sh_size / 4 + 1) * 4); + } + } + else + { + return (-1); + } + free (mem); + } + } + + free (strtab); + return (ehdr.e_entry); +} + +int +elf_load (char *fname, int readsym) +{ + FILE *fp; + int res; + + if (!readsym) + { + if ((fp = fopen (fname, "r")) == NULL) + { + printf ("file not found\n"); + return (-1); + } + + + res = read_elf_header (fp); + if (res < 0) + printf ("File read error\n"); + + } + else + { + res = read_elf_body (); + if (res < 0) + printf ("File read error\n"); + else + printf (" Loaded %s, entry 0x%08x\n", fname, res); + fclose (efile.fp); + } + return res; + +} |