qemu/include/hw/elf_ops.h
Thomas Huth 5dce07e1cb elf-loader: Provide the possibility to relocate s390 ELF files
On s390, we would like to load our "BIOS" s390-ccw.img to the end of the
RAM. Therefor we need the possibility to relocate the ELF file so that
it can also run from different addresses. This patch adds the necessary
code to the QEMU ELF loader function.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Message-Id: <1425895973-15239-2-git-send-email-thuth@linux.vnet.ibm.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2015-03-10 09:26:27 +01:00

392 lines
12 KiB
C

static void glue(bswap_ehdr, SZ)(struct elfhdr *ehdr)
{
bswap16s(&ehdr->e_type); /* Object file type */
bswap16s(&ehdr->e_machine); /* Architecture */
bswap32s(&ehdr->e_version); /* Object file version */
bswapSZs(&ehdr->e_entry); /* Entry point virtual address */
bswapSZs(&ehdr->e_phoff); /* Program header table file offset */
bswapSZs(&ehdr->e_shoff); /* Section header table file offset */
bswap32s(&ehdr->e_flags); /* Processor-specific flags */
bswap16s(&ehdr->e_ehsize); /* ELF header size in bytes */
bswap16s(&ehdr->e_phentsize); /* Program header table entry size */
bswap16s(&ehdr->e_phnum); /* Program header table entry count */
bswap16s(&ehdr->e_shentsize); /* Section header table entry size */
bswap16s(&ehdr->e_shnum); /* Section header table entry count */
bswap16s(&ehdr->e_shstrndx); /* Section header string table index */
}
static void glue(bswap_phdr, SZ)(struct elf_phdr *phdr)
{
bswap32s(&phdr->p_type); /* Segment type */
bswapSZs(&phdr->p_offset); /* Segment file offset */
bswapSZs(&phdr->p_vaddr); /* Segment virtual address */
bswapSZs(&phdr->p_paddr); /* Segment physical address */
bswapSZs(&phdr->p_filesz); /* Segment size in file */
bswapSZs(&phdr->p_memsz); /* Segment size in memory */
bswap32s(&phdr->p_flags); /* Segment flags */
bswapSZs(&phdr->p_align); /* Segment alignment */
}
static void glue(bswap_shdr, SZ)(struct elf_shdr *shdr)
{
bswap32s(&shdr->sh_name);
bswap32s(&shdr->sh_type);
bswapSZs(&shdr->sh_flags);
bswapSZs(&shdr->sh_addr);
bswapSZs(&shdr->sh_offset);
bswapSZs(&shdr->sh_size);
bswap32s(&shdr->sh_link);
bswap32s(&shdr->sh_info);
bswapSZs(&shdr->sh_addralign);
bswapSZs(&shdr->sh_entsize);
}
static void glue(bswap_sym, SZ)(struct elf_sym *sym)
{
bswap32s(&sym->st_name);
bswapSZs(&sym->st_value);
bswapSZs(&sym->st_size);
bswap16s(&sym->st_shndx);
}
static void glue(bswap_rela, SZ)(struct elf_rela *rela)
{
bswapSZs(&rela->r_offset);
bswapSZs(&rela->r_info);
bswapSZs((elf_word *)&rela->r_addend);
}
static struct elf_shdr *glue(find_section, SZ)(struct elf_shdr *shdr_table,
int n, int type)
{
int i;
for(i=0;i<n;i++) {
if (shdr_table[i].sh_type == type)
return shdr_table + i;
}
return NULL;
}
static int glue(symfind, SZ)(const void *s0, const void *s1)
{
hwaddr addr = *(hwaddr *)s0;
struct elf_sym *sym = (struct elf_sym *)s1;
int result = 0;
if (addr < sym->st_value) {
result = -1;
} else if (addr >= sym->st_value + sym->st_size) {
result = 1;
}
return result;
}
static const char *glue(lookup_symbol, SZ)(struct syminfo *s,
hwaddr orig_addr)
{
struct elf_sym *syms = glue(s->disas_symtab.elf, SZ);
struct elf_sym *sym;
sym = bsearch(&orig_addr, syms, s->disas_num_syms, sizeof(*syms),
glue(symfind, SZ));
if (sym != NULL) {
return s->disas_strtab + sym->st_name;
}
return "";
}
static int glue(symcmp, SZ)(const void *s0, const void *s1)
{
struct elf_sym *sym0 = (struct elf_sym *)s0;
struct elf_sym *sym1 = (struct elf_sym *)s1;
return (sym0->st_value < sym1->st_value)
? -1
: ((sym0->st_value > sym1->st_value) ? 1 : 0);
}
static int glue(load_symbols, SZ)(struct elfhdr *ehdr, int fd, int must_swab,
int clear_lsb)
{
struct elf_shdr *symtab, *strtab, *shdr_table = NULL;
struct elf_sym *syms = NULL;
struct syminfo *s;
int nsyms, i;
char *str = NULL;
shdr_table = load_at(fd, ehdr->e_shoff,
sizeof(struct elf_shdr) * ehdr->e_shnum);
if (!shdr_table)
return -1;
if (must_swab) {
for (i = 0; i < ehdr->e_shnum; i++) {
glue(bswap_shdr, SZ)(shdr_table + i);
}
}
symtab = glue(find_section, SZ)(shdr_table, ehdr->e_shnum, SHT_SYMTAB);
if (!symtab)
goto fail;
syms = load_at(fd, symtab->sh_offset, symtab->sh_size);
if (!syms)
goto fail;
nsyms = symtab->sh_size / sizeof(struct elf_sym);
i = 0;
while (i < nsyms) {
if (must_swab)
glue(bswap_sym, SZ)(&syms[i]);
/* We are only interested in function symbols.
Throw everything else away. */
if (syms[i].st_shndx == SHN_UNDEF ||
syms[i].st_shndx >= SHN_LORESERVE ||
ELF_ST_TYPE(syms[i].st_info) != STT_FUNC) {
nsyms--;
if (i < nsyms) {
syms[i] = syms[nsyms];
}
continue;
}
if (clear_lsb) {
/* The bottom address bit marks a Thumb or MIPS16 symbol. */
syms[i].st_value &= ~(glue(glue(Elf, SZ), _Addr))1;
}
i++;
}
syms = g_realloc(syms, nsyms * sizeof(*syms));
qsort(syms, nsyms, sizeof(*syms), glue(symcmp, SZ));
for (i = 0; i < nsyms - 1; i++) {
if (syms[i].st_size == 0) {
syms[i].st_size = syms[i + 1].st_value - syms[i].st_value;
}
}
/* String table */
if (symtab->sh_link >= ehdr->e_shnum)
goto fail;
strtab = &shdr_table[symtab->sh_link];
str = load_at(fd, strtab->sh_offset, strtab->sh_size);
if (!str)
goto fail;
/* Commit */
s = g_malloc0(sizeof(*s));
s->lookup_symbol = glue(lookup_symbol, SZ);
glue(s->disas_symtab.elf, SZ) = syms;
s->disas_num_syms = nsyms;
s->disas_strtab = str;
s->next = syminfos;
syminfos = s;
g_free(shdr_table);
return 0;
fail:
g_free(syms);
g_free(str);
g_free(shdr_table);
return -1;
}
static int glue(elf_reloc, SZ)(struct elfhdr *ehdr, int fd, int must_swab,
uint64_t (*translate_fn)(void *, uint64_t),
void *translate_opaque, uint8_t *data,
struct elf_phdr *ph, int elf_machine)
{
struct elf_shdr *reltab, *shdr_table = NULL;
struct elf_rela *rels = NULL;
int nrels, i, ret = -1;
elf_word wordval;
void *addr;
shdr_table = load_at(fd, ehdr->e_shoff,
sizeof(struct elf_shdr) * ehdr->e_shnum);
if (!shdr_table) {
return -1;
}
if (must_swab) {
for (i = 0; i < ehdr->e_shnum; i++) {
glue(bswap_shdr, SZ)(&shdr_table[i]);
}
}
reltab = glue(find_section, SZ)(shdr_table, ehdr->e_shnum, SHT_RELA);
if (!reltab) {
goto fail;
}
rels = load_at(fd, reltab->sh_offset, reltab->sh_size);
if (!rels) {
goto fail;
}
nrels = reltab->sh_size / sizeof(struct elf_rela);
for (i = 0; i < nrels; i++) {
if (must_swab) {
glue(bswap_rela, SZ)(&rels[i]);
}
if (rels[i].r_offset < ph->p_vaddr ||
rels[i].r_offset >= ph->p_vaddr + ph->p_filesz) {
continue;
}
addr = &data[rels[i].r_offset - ph->p_vaddr];
switch (elf_machine) {
case EM_S390:
switch (rels[i].r_info) {
case R_390_RELATIVE:
wordval = *(elf_word *)addr;
if (must_swab) {
bswapSZs(&wordval);
}
wordval = translate_fn(translate_opaque, wordval);
if (must_swab) {
bswapSZs(&wordval);
}
*(elf_word *)addr = wordval;
break;
default:
fprintf(stderr, "Unsupported relocation type %i!\n",
(int)rels[i].r_info);
}
}
}
ret = 0;
fail:
g_free(rels);
g_free(shdr_table);
return ret;
}
static int glue(load_elf, SZ)(const char *name, int fd,
uint64_t (*translate_fn)(void *, uint64_t),
void *translate_opaque,
int must_swab, uint64_t *pentry,
uint64_t *lowaddr, uint64_t *highaddr,
int elf_machine, int clear_lsb)
{
struct elfhdr ehdr;
struct elf_phdr *phdr = NULL, *ph;
int size, i, total_size;
elf_word mem_size, file_size;
uint64_t addr, low = (uint64_t)-1, high = 0;
uint8_t *data = NULL;
char label[128];
int ret = ELF_LOAD_FAILED;
if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
goto fail;
if (must_swab) {
glue(bswap_ehdr, SZ)(&ehdr);
}
switch (elf_machine) {
case EM_PPC64:
if (EM_PPC64 != ehdr.e_machine)
if (EM_PPC != ehdr.e_machine) {
ret = ELF_LOAD_WRONG_ARCH;
goto fail;
}
break;
case EM_X86_64:
if (EM_X86_64 != ehdr.e_machine)
if (EM_386 != ehdr.e_machine) {
ret = ELF_LOAD_WRONG_ARCH;
goto fail;
}
break;
case EM_MICROBLAZE:
if (EM_MICROBLAZE != ehdr.e_machine)
if (EM_MICROBLAZE_OLD != ehdr.e_machine) {
ret = ELF_LOAD_WRONG_ARCH;
goto fail;
}
break;
default:
if (elf_machine != ehdr.e_machine) {
ret = ELF_LOAD_WRONG_ARCH;
goto fail;
}
}
if (pentry)
*pentry = (uint64_t)(elf_sword)ehdr.e_entry;
glue(load_symbols, SZ)(&ehdr, fd, must_swab, clear_lsb);
size = ehdr.e_phnum * sizeof(phdr[0]);
lseek(fd, ehdr.e_phoff, SEEK_SET);
phdr = g_malloc0(size);
if (!phdr)
goto fail;
if (read(fd, phdr, size) != size)
goto fail;
if (must_swab) {
for(i = 0; i < ehdr.e_phnum; i++) {
ph = &phdr[i];
glue(bswap_phdr, SZ)(ph);
}
}
total_size = 0;
for(i = 0; i < ehdr.e_phnum; i++) {
ph = &phdr[i];
if (ph->p_type == PT_LOAD) {
mem_size = ph->p_memsz; /* Size of the ROM */
file_size = ph->p_filesz; /* Size of the allocated data */
data = g_malloc0(file_size);
if (ph->p_filesz > 0) {
if (lseek(fd, ph->p_offset, SEEK_SET) < 0) {
goto fail;
}
if (read(fd, data, file_size) != file_size) {
goto fail;
}
}
/* address_offset is hack for kernel images that are
linked at the wrong physical address. */
if (translate_fn) {
addr = translate_fn(translate_opaque, ph->p_paddr);
glue(elf_reloc, SZ)(&ehdr, fd, must_swab, translate_fn,
translate_opaque, data, ph, elf_machine);
} else {
addr = ph->p_paddr;
}
/* the entry pointer in the ELF header is a virtual
* address, if the text segments paddr and vaddr differ
* we need to adjust the entry */
if (pentry && !translate_fn &&
ph->p_vaddr != ph->p_paddr &&
ehdr.e_entry >= ph->p_vaddr &&
ehdr.e_entry < ph->p_vaddr + ph->p_filesz &&
ph->p_flags & PF_X) {
*pentry = ehdr.e_entry - ph->p_vaddr + ph->p_paddr;
}
snprintf(label, sizeof(label), "phdr #%d: %s", i, name);
/* rom_add_elf_program() seize the ownership of 'data' */
rom_add_elf_program(label, data, file_size, mem_size, addr);
total_size += mem_size;
if (addr < low)
low = addr;
if ((addr + mem_size) > high)
high = addr + mem_size;
data = NULL;
}
}
g_free(phdr);
if (lowaddr)
*lowaddr = (uint64_t)(elf_sword)low;
if (highaddr)
*highaddr = (uint64_t)(elf_sword)high;
return total_size;
fail:
g_free(data);
g_free(phdr);
return ret;
}