elf_loader.c
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/*
* libspe2 - A wrapper to allow direct execution of SPE binaries
* Copyright (C) 2005 IBM Corp.
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License,
* or (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <elf.h>
#include <errno.h>
#include <fcntl.h>
#include <malloc.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "elf_loader.h"
#include "spebase.h"
#ifdef DEBUG
static void display_debug_output(Elf32_Ehdr *elf_start, Elf32_Shdr *sh);
#endif /*DEBUG*/
#define __PRINTF(fmt, args...) { fprintf(stderr,fmt , ## args); }
#ifdef DEBUG
#define DEBUG_PRINTF(fmt, args...) __PRINTF(fmt , ## args)
#define TAG DEBUG_PRINTF("TAG: %d@%s\n", __LINE__, __FILE__);
#else
#define DEBUG_PRINTF(fmt, args...)
#define TAG
#endif
static const unsigned char expected[EI_PAD] = {
[EI_MAG0] = ELFMAG0,
[EI_MAG1] = ELFMAG1,
[EI_MAG2] = ELFMAG2,
[EI_MAG3] = ELFMAG3,
[EI_CLASS] = ELFCLASS32,
[EI_DATA] = ELFDATA2MSB,
[EI_VERSION] = EV_CURRENT,
[EI_OSABI] = ELFOSABI_SYSV,
[EI_ABIVERSION] = 0
};
static int
check_spe_elf(Elf32_Ehdr *ehdr)
{
/* Validate ELF */
if (memcmp (ehdr->e_ident, expected, EI_PAD) != 0)
{
DEBUG_PRINTF ("invalid ELF header.\n");
DEBUG_PRINTF ("expected 0x%016llX != 0x%016llX\n",
*(long long *) expected, *(long long *) (ehdr->e_ident));
errno = EINVAL;
return -errno;
}
/* Validate the machine type */
if (ehdr->e_machine != 0x17)
{
DEBUG_PRINTF ("not an SPE ELF object");
errno = EINVAL;
return -errno;
}
/* Validate ELF object type. */
if (ehdr->e_type != ET_EXEC)
{
DEBUG_PRINTF ("invalid SPE ELF type.\n");
DEBUG_PRINTF ("SPE type %d != %d\n", ehdr->e_type, ET_EXEC);
errno = EINVAL;
DEBUG_PRINTF ("parse_spu_elf(): errno=%d.\n", errno);
return -errno;
}
return 0;
}
int
_base_spe_verify_spe_elf_image(spe_program_handle_t *handle)
{
Elf32_Ehdr *ehdr;
void *elf_start;
elf_start = handle->elf_image;
ehdr = (Elf32_Ehdr *)(handle->elf_image);
return check_spe_elf(ehdr);
}
int
_base_spe_parse_isolated_elf(spe_program_handle_t *handle,
uint64_t *addr, uint32_t *size)
{
Elf32_Ehdr *ehdr = (Elf32_Ehdr *)handle->elf_image;
Elf32_Phdr *phdr;
if (!ehdr) {
DEBUG_PRINTF("No ELF image has been loaded\n");
errno = EINVAL;
return -errno;
}
if (ehdr->e_phentsize != sizeof(*phdr)) {
DEBUG_PRINTF("Invalid program header format (phdr size=%d)\n",
ehdr->e_phentsize);
errno = EINVAL;
return -errno;
}
if (ehdr->e_phnum != 1) {
DEBUG_PRINTF("Invalid program header count (%d), expected 1\n",
ehdr->e_phnum);
errno = EINVAL;
return -errno;
}
phdr = (Elf32_Phdr *)(handle->elf_image + ehdr->e_phoff);
if (phdr->p_type != PT_LOAD || phdr->p_memsz == 0) {
DEBUG_PRINTF("SPE program segment is not loadable (type=%x)\n",
phdr->p_type);
errno = EINVAL;
return -errno;
}
if (addr)
*addr = (uint64_t)(unsigned long)
(handle->elf_image + phdr->p_offset);
if (size)
*size = phdr->p_memsz;
return 0;
}
static int
overlay(Elf32_Phdr *ph, Elf32_Phdr *prev_ph)
{
/*
* If our ph segment virtual address fits within that of the
* previous ph, this is an overlay.
*/
if (prev_ph && (ph->p_vaddr >= prev_ph->p_vaddr) &&
(ph->p_vaddr < (prev_ph->p_vaddr + prev_ph->p_memsz)))
return 1;
else
return 0;
}
static void
copy_to_ld_buffer(spe_program_handle_t *handle, void *buffer, Elf32_Phdr
*ph, Elf32_Off toe_addr, long toe_size)
{
void *start = handle->elf_image;
DEBUG_PRINTF("SPE_LOAD %p (0x%x) -> %p (0x%x) (%i bytes)\n",
buffer + ph->p_vaddr, ph->p_vaddr, start + ph->p_offset,
ph->p_offset, ph->p_filesz);
/* toe segment comes from the shadow */
if (ph->p_vaddr == toe_addr) {
/* still makes a copy if toe is buried with other
* sections */
if (toe_size != ph->p_filesz && ph->p_filesz) {
DEBUG_PRINTF("loading base copy\n");
memcpy(buffer + ph->p_vaddr, start + ph->p_offset,
ph->p_filesz);
}
/* overlay only the total toe section size */
DEBUG_PRINTF("loading toe %X %X\n", ph->p_offset, toe_addr);
memcpy(buffer + ph->p_vaddr, handle->toe_shadow, toe_size);
} else if (ph->p_filesz) {
memcpy(buffer + ph->p_vaddr, start + ph->p_offset,
ph->p_filesz);
}
DEBUG_PRINTF("done ...\n");
}
int
_base_spe_load_spe_elf (spe_program_handle_t *handle, void *ld_buffer, struct spe_ld_info *ld_info)
{
Elf32_Ehdr *ehdr;
Elf32_Phdr *phdr;
Elf32_Phdr *ph, *prev_ph;
Elf32_Shdr *shdr;
Elf32_Shdr *sh;
Elf32_Off toe_addr = 0;
long toe_size = 0;
char* str_table = 0;
int num_load_seg = 0;
void *elf_start;
int ret;
DEBUG_PRINTF ("load_spe_elf(%p, %p)\n", handle, ld_buffer);
elf_start = handle->elf_image;
DEBUG_PRINTF ("load_spe_elf(%p, %p)\n", handle->elf_image, ld_buffer);
ehdr = (Elf32_Ehdr *)(handle->elf_image);
/* Check for a Valid SPE ELF Image (again) */
if ((ret=check_spe_elf(ehdr)))
return ret;
/* Start processing headers */
phdr = (Elf32_Phdr *) ((char *) ehdr + ehdr->e_phoff);
shdr = (Elf32_Shdr *) ((char *) ehdr + ehdr->e_shoff);
str_table = (char*)ehdr + shdr[ehdr->e_shstrndx].sh_offset;
/* traverse the sections to locate the toe segment */
/* by specification, the toe sections are grouped together in a segment */
for (sh = shdr; sh < &shdr[ehdr->e_shnum]; ++sh)
{
DEBUG_PRINTF("section name: %s ( start: 0x%04x, size: 0x%04x)\n", str_table+sh->sh_name, sh->sh_offset, sh->sh_size );
if (strcmp(".toe", str_table+sh->sh_name) == 0) {
DEBUG_PRINTF("section offset: %d\n", sh->sh_offset);
toe_size += sh->sh_size;
if ((toe_addr == 0) || (toe_addr > sh->sh_addr))
toe_addr = sh->sh_addr;
}
/* Disabled : Actually not needed, only good for testing
if (strcmp(".bss", str_table+sh->sh_name) == 0) {
DEBUG_PRINTF("zeroing .bss section:\n");
DEBUG_PRINTF("section offset: 0x%04x\n", sh->sh_offset);
DEBUG_PRINTF("section size: 0x%04x\n", sh->sh_size);
memset(ld_buffer + sh->sh_offset, 0, sh->sh_size);
} */
#ifdef DEBUG
if (strcmp(".note.spu_name", str_table+sh->sh_name) == 0)
display_debug_output(elf_start, sh);
#endif /*DEBUG*/
}
/*
* Load all PT_LOAD segments onto the SPE local store buffer.
*/
DEBUG_PRINTF("Segments: 0x%x\n", ehdr->e_phnum);
for (ph = phdr, prev_ph = NULL; ph < &phdr[ehdr->e_phnum]; ++ph) {
switch (ph->p_type) {
case PT_LOAD:
if (!overlay(ph, prev_ph)) {
if (ph->p_filesz < ph->p_memsz) {
DEBUG_PRINTF("padding loaded image with zeros:\n");
DEBUG_PRINTF("start: 0x%04x\n", ph->p_vaddr + ph->p_filesz);
DEBUG_PRINTF("length: 0x%04x\n", ph->p_memsz - ph->p_filesz);
memset(ld_buffer + ph->p_vaddr + ph->p_filesz, 0, ph->p_memsz - ph->p_filesz);
}
copy_to_ld_buffer(handle, ld_buffer, ph,
toe_addr, toe_size);
num_load_seg++;
}
break;
case PT_NOTE:
DEBUG_PRINTF("SPE_LOAD found PT_NOTE\n");
break;
}
}
if (num_load_seg == 0)
{
DEBUG_PRINTF ("no segments to load");
errno = EINVAL;
return -errno;
}
/* Remember where the code wants to be started */
ld_info->entry = ehdr->e_entry;
DEBUG_PRINTF ("entry = 0x%x\n", ehdr->e_entry);
return 0;
}
#ifdef DEBUG
static void
display_debug_output(Elf32_Ehdr *elf_start, Elf32_Shdr *sh)
{
typedef struct
{
unsigned long namesz;
unsigned long descsz;
unsigned long type;
char name[8];
char lookupname[32];
} ELF_NOTE;
ELF_NOTE *note = (ELF_NOTE *)((void *)elf_start+sh->sh_offset);
printf ("Loading SPE program : %s\n", note->lookupname);
printf ("SPU LS Entry Addr : 0x%05x\n", elf_start->e_entry);
}
#endif /*DEBUG*/
static int
toe_check_syms(Elf32_Ehdr *ehdr, Elf32_Shdr *sh)
{
Elf32_Sym *sym, *sym_hdr, *sym_end;
Elf32_Shdr *shdr;
char *str_table;
char *sym_name;
int ret;
shdr = (Elf32_Shdr*) ((char*) ehdr + ehdr->e_shoff);
sym_hdr = (Elf32_Sym*) ((char*) ehdr + sh->sh_offset);
sym_end = (Elf32_Sym*) ((char*) ehdr + sh->sh_offset + sh->sh_size);
str_table = (char*)ehdr + shdr[sh->sh_link].sh_offset;
ret = 0;
for (sym = sym_hdr; sym < sym_end; sym++)
if (sym->st_name) {
sym_name = str_table + sym->st_name;
if ((strncmp(sym_name, "_EAR_", 5) == 0) &&
(strcmp(sym_name, "_EAR_") != 0)) {
/*
* We have a prefix of _EAR_ followed by
* something else. This is not currently
* (and might not ever be) supported: for
* a _EAR_foo, it requires a lookup of foo
* in the ppu ELF file.
*/
fprintf(stderr, "Invalid _EAR_ symbol '%s'\n",
sym_name);
errno = EINVAL;
ret = 1;
}
}
return ret;
}
int _base_spe_toe_ear (spe_program_handle_t *speh)
{
Elf32_Ehdr *ehdr;
Elf32_Shdr *shdr, *sh;
char *str_table;
char **ch;
int ret;
long toe_size;
ehdr = (Elf32_Ehdr*) (speh->elf_image);
shdr = (Elf32_Shdr*) ((char*) ehdr + ehdr->e_shoff);
str_table = (char*)ehdr + shdr[ehdr->e_shstrndx].sh_offset;
toe_size = 0;
for (sh = shdr; sh < &shdr[ehdr->e_shnum]; ++sh)
if (strcmp(".toe", str_table + sh->sh_name) == 0)
toe_size += sh->sh_size;
ret = 0;
if (toe_size > 0) {
for (sh = shdr; sh < &shdr[ehdr->e_shnum]; ++sh)
if (sh->sh_type == SHT_SYMTAB || sh->sh_type ==
SHT_DYNSYM)
ret = toe_check_syms(ehdr, sh);
if (!ret && toe_size != 16) {
/* Paranoia */
fprintf(stderr, "Unexpected toe size of %ld\n",
toe_size);
errno = EINVAL;
ret = 1;
}
}
if (!ret && toe_size) {
/*
* Allocate toe_shadow, and fill it with elf_image.
*/
speh->toe_shadow = malloc(toe_size);
if (speh->toe_shadow) {
ch = (char**) speh->toe_shadow;
if (sizeof(char*) == 8) {
ch[0] = (char*) speh->elf_image;
ch[1] = 0;
} else {
ch[0] = 0;
ch[1] = (char*) speh->elf_image;
ch[2] = 0;
ch[3] = 0;
}
} else {
errno = ENOMEM;
ret = 1;
}
}
return ret;
}