linux/arch/mips/boot/tools/relocs.c
Alexey Dobriyan 70e79866ab ELF: fix all "Elf" typos
ELF is acronym and therefore should be spelled in all caps.

I left one exception at Documentation/arm/nwfpe/nwfpe.rst which looks like
being written in the first person.

Link: https://lkml.kernel.org/r/Y/3wGWQviIOkyLJW@p183
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-08 13:45:37 -07:00

682 lines
17 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* This is included from relocs_32/64.c */
#define ElfW(type) _ElfW(ELF_BITS, type)
#define _ElfW(bits, type) __ElfW(bits, type)
#define __ElfW(bits, type) Elf##bits##_##type
#define Elf_Addr ElfW(Addr)
#define Elf_Ehdr ElfW(Ehdr)
#define Elf_Phdr ElfW(Phdr)
#define Elf_Shdr ElfW(Shdr)
#define Elf_Sym ElfW(Sym)
static Elf_Ehdr ehdr;
struct relocs {
uint32_t *offset;
unsigned long count;
unsigned long size;
};
static struct relocs relocs;
struct section {
Elf_Shdr shdr;
struct section *link;
Elf_Sym *symtab;
Elf_Rel *reltab;
char *strtab;
long shdr_offset;
};
static struct section *secs;
static const char * const regex_sym_kernel = {
/* Symbols matching these regex's should never be relocated */
"^(__crc_)",
};
static regex_t sym_regex_c;
static int regex_skip_reloc(const char *sym_name)
{
return !regexec(&sym_regex_c, sym_name, 0, NULL, 0);
}
static void regex_init(void)
{
char errbuf[128];
int err;
err = regcomp(&sym_regex_c, regex_sym_kernel,
REG_EXTENDED|REG_NOSUB);
if (err) {
regerror(err, &sym_regex_c, errbuf, sizeof(errbuf));
die("%s", errbuf);
}
}
static const char *rel_type(unsigned type)
{
static const char * const type_name[] = {
#define REL_TYPE(X)[X] = #X
REL_TYPE(R_MIPS_NONE),
REL_TYPE(R_MIPS_16),
REL_TYPE(R_MIPS_32),
REL_TYPE(R_MIPS_REL32),
REL_TYPE(R_MIPS_26),
REL_TYPE(R_MIPS_HI16),
REL_TYPE(R_MIPS_LO16),
REL_TYPE(R_MIPS_GPREL16),
REL_TYPE(R_MIPS_LITERAL),
REL_TYPE(R_MIPS_GOT16),
REL_TYPE(R_MIPS_PC16),
REL_TYPE(R_MIPS_CALL16),
REL_TYPE(R_MIPS_GPREL32),
REL_TYPE(R_MIPS_64),
REL_TYPE(R_MIPS_HIGHER),
REL_TYPE(R_MIPS_HIGHEST),
REL_TYPE(R_MIPS_PC21_S2),
REL_TYPE(R_MIPS_PC26_S2),
#undef REL_TYPE
};
const char *name = "unknown type rel type name";
if (type < ARRAY_SIZE(type_name) && type_name[type])
name = type_name[type];
return name;
}
static const char *sec_name(unsigned shndx)
{
const char *sec_strtab;
const char *name;
sec_strtab = secs[ehdr.e_shstrndx].strtab;
if (shndx < ehdr.e_shnum)
name = sec_strtab + secs[shndx].shdr.sh_name;
else if (shndx == SHN_ABS)
name = "ABSOLUTE";
else if (shndx == SHN_COMMON)
name = "COMMON";
else
name = "<noname>";
return name;
}
static struct section *sec_lookup(const char *secname)
{
int i;
for (i = 0; i < ehdr.e_shnum; i++)
if (strcmp(secname, sec_name(i)) == 0)
return &secs[i];
return NULL;
}
static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
{
const char *name;
if (sym->st_name)
name = sym_strtab + sym->st_name;
else
name = sec_name(sym->st_shndx);
return name;
}
#if BYTE_ORDER == LITTLE_ENDIAN
#define le16_to_cpu(val) (val)
#define le32_to_cpu(val) (val)
#define le64_to_cpu(val) (val)
#define be16_to_cpu(val) bswap_16(val)
#define be32_to_cpu(val) bswap_32(val)
#define be64_to_cpu(val) bswap_64(val)
#define cpu_to_le16(val) (val)
#define cpu_to_le32(val) (val)
#define cpu_to_le64(val) (val)
#define cpu_to_be16(val) bswap_16(val)
#define cpu_to_be32(val) bswap_32(val)
#define cpu_to_be64(val) bswap_64(val)
#endif
#if BYTE_ORDER == BIG_ENDIAN
#define le16_to_cpu(val) bswap_16(val)
#define le32_to_cpu(val) bswap_32(val)
#define le64_to_cpu(val) bswap_64(val)
#define be16_to_cpu(val) (val)
#define be32_to_cpu(val) (val)
#define be64_to_cpu(val) (val)
#define cpu_to_le16(val) bswap_16(val)
#define cpu_to_le32(val) bswap_32(val)
#define cpu_to_le64(val) bswap_64(val)
#define cpu_to_be16(val) (val)
#define cpu_to_be32(val) (val)
#define cpu_to_be64(val) (val)
#endif
static uint16_t elf16_to_cpu(uint16_t val)
{
if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
return le16_to_cpu(val);
else
return be16_to_cpu(val);
}
static uint32_t elf32_to_cpu(uint32_t val)
{
if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
return le32_to_cpu(val);
else
return be32_to_cpu(val);
}
static uint32_t cpu_to_elf32(uint32_t val)
{
if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
return cpu_to_le32(val);
else
return cpu_to_be32(val);
}
#define elf_half_to_cpu(x) elf16_to_cpu(x)
#define elf_word_to_cpu(x) elf32_to_cpu(x)
#if ELF_BITS == 64
static uint64_t elf64_to_cpu(uint64_t val)
{
if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
return le64_to_cpu(val);
else
return be64_to_cpu(val);
}
#define elf_addr_to_cpu(x) elf64_to_cpu(x)
#define elf_off_to_cpu(x) elf64_to_cpu(x)
#define elf_xword_to_cpu(x) elf64_to_cpu(x)
#else
#define elf_addr_to_cpu(x) elf32_to_cpu(x)
#define elf_off_to_cpu(x) elf32_to_cpu(x)
#define elf_xword_to_cpu(x) elf32_to_cpu(x)
#endif
static void read_ehdr(FILE *fp)
{
if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1)
die("Cannot read ELF header: %s\n", strerror(errno));
if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0)
die("No ELF magic\n");
if (ehdr.e_ident[EI_CLASS] != ELF_CLASS)
die("Not a %d bit executable\n", ELF_BITS);
if ((ehdr.e_ident[EI_DATA] != ELFDATA2LSB) &&
(ehdr.e_ident[EI_DATA] != ELFDATA2MSB))
die("Unknown ELF Endianness\n");
if (ehdr.e_ident[EI_VERSION] != EV_CURRENT)
die("Unknown ELF version\n");
/* Convert the fields to native endian */
ehdr.e_type = elf_half_to_cpu(ehdr.e_type);
ehdr.e_machine = elf_half_to_cpu(ehdr.e_machine);
ehdr.e_version = elf_word_to_cpu(ehdr.e_version);
ehdr.e_entry = elf_addr_to_cpu(ehdr.e_entry);
ehdr.e_phoff = elf_off_to_cpu(ehdr.e_phoff);
ehdr.e_shoff = elf_off_to_cpu(ehdr.e_shoff);
ehdr.e_flags = elf_word_to_cpu(ehdr.e_flags);
ehdr.e_ehsize = elf_half_to_cpu(ehdr.e_ehsize);
ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
ehdr.e_phnum = elf_half_to_cpu(ehdr.e_phnum);
ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum);
ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx);
if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
die("Unsupported ELF header type\n");
if (ehdr.e_machine != ELF_MACHINE)
die("Not for %s\n", ELF_MACHINE_NAME);
if (ehdr.e_version != EV_CURRENT)
die("Unknown ELF version\n");
if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
die("Bad ELF header size\n");
if (ehdr.e_phentsize != sizeof(Elf_Phdr))
die("Bad program header entry\n");
if (ehdr.e_shentsize != sizeof(Elf_Shdr))
die("Bad section header entry\n");
if (ehdr.e_shstrndx >= ehdr.e_shnum)
die("String table index out of bounds\n");
}
static void read_shdrs(FILE *fp)
{
int i;
Elf_Shdr shdr;
secs = calloc(ehdr.e_shnum, sizeof(struct section));
if (!secs)
die("Unable to allocate %d section headers\n", ehdr.e_shnum);
if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno));
for (i = 0; i < ehdr.e_shnum; i++) {
struct section *sec = &secs[i];
sec->shdr_offset = ftell(fp);
if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
die("Cannot read ELF section headers %d/%d: %s\n",
i, ehdr.e_shnum, strerror(errno));
sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name);
sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type);
sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags);
sec->shdr.sh_addr = elf_addr_to_cpu(shdr.sh_addr);
sec->shdr.sh_offset = elf_off_to_cpu(shdr.sh_offset);
sec->shdr.sh_size = elf_xword_to_cpu(shdr.sh_size);
sec->shdr.sh_link = elf_word_to_cpu(shdr.sh_link);
sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info);
sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize);
if (sec->shdr.sh_link < ehdr.e_shnum)
sec->link = &secs[sec->shdr.sh_link];
}
}
static void read_strtabs(FILE *fp)
{
int i;
for (i = 0; i < ehdr.e_shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_STRTAB)
continue;
sec->strtab = malloc(sec->shdr.sh_size);
if (!sec->strtab)
die("malloc of %d bytes for strtab failed\n",
sec->shdr.sh_size);
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0)
die("Seek to %d failed: %s\n",
sec->shdr.sh_offset, strerror(errno));
if (fread(sec->strtab, 1, sec->shdr.sh_size, fp) !=
sec->shdr.sh_size)
die("Cannot read symbol table: %s\n", strerror(errno));
}
}
static void read_symtabs(FILE *fp)
{
int i, j;
for (i = 0; i < ehdr.e_shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_SYMTAB)
continue;
sec->symtab = malloc(sec->shdr.sh_size);
if (!sec->symtab)
die("malloc of %d bytes for symtab failed\n",
sec->shdr.sh_size);
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0)
die("Seek to %d failed: %s\n",
sec->shdr.sh_offset, strerror(errno));
if (fread(sec->symtab, 1, sec->shdr.sh_size, fp) !=
sec->shdr.sh_size)
die("Cannot read symbol table: %s\n", strerror(errno));
for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
Elf_Sym *sym = &sec->symtab[j];
sym->st_name = elf_word_to_cpu(sym->st_name);
sym->st_value = elf_addr_to_cpu(sym->st_value);
sym->st_size = elf_xword_to_cpu(sym->st_size);
sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
}
}
}
static void read_relocs(FILE *fp)
{
static unsigned long base;
int i, j;
if (!base) {
struct section *sec = sec_lookup(".text");
if (!sec)
die("Could not find .text section\n");
base = sec->shdr.sh_addr;
}
for (i = 0; i < ehdr.e_shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_REL_TYPE)
continue;
sec->reltab = malloc(sec->shdr.sh_size);
if (!sec->reltab)
die("malloc of %d bytes for relocs failed\n",
sec->shdr.sh_size);
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0)
die("Seek to %d failed: %s\n",
sec->shdr.sh_offset, strerror(errno));
if (fread(sec->reltab, 1, sec->shdr.sh_size, fp) !=
sec->shdr.sh_size)
die("Cannot read symbol table: %s\n", strerror(errno));
for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
Elf_Rel *rel = &sec->reltab[j];
rel->r_offset = elf_addr_to_cpu(rel->r_offset);
/* Set offset into kernel image */
rel->r_offset -= base;
#if (ELF_BITS == 32)
rel->r_info = elf_xword_to_cpu(rel->r_info);
#else
/* Convert MIPS64 RELA format - only the symbol
* index needs converting to native endianness
*/
rel->r_info = rel->r_info;
ELF_R_SYM(rel->r_info) = elf32_to_cpu(ELF_R_SYM(rel->r_info));
#endif
#if (SHT_REL_TYPE == SHT_RELA)
rel->r_addend = elf_xword_to_cpu(rel->r_addend);
#endif
}
}
}
static void remove_relocs(FILE *fp)
{
int i;
Elf_Shdr shdr;
for (i = 0; i < ehdr.e_shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_REL_TYPE)
continue;
if (fseek(fp, sec->shdr_offset, SEEK_SET) < 0)
die("Seek to %d failed: %s\n",
sec->shdr_offset, strerror(errno));
if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
die("Cannot read ELF section headers %d/%d: %s\n",
i, ehdr.e_shnum, strerror(errno));
/* Set relocation section size to 0, effectively removing it.
* This is necessary due to lack of support for relocations
* in objcopy when creating 32bit elf from 64bit elf.
*/
shdr.sh_size = 0;
if (fseek(fp, sec->shdr_offset, SEEK_SET) < 0)
die("Seek to %d failed: %s\n",
sec->shdr_offset, strerror(errno));
if (fwrite(&shdr, sizeof(shdr), 1, fp) != 1)
die("Cannot write ELF section headers %d/%d: %s\n",
i, ehdr.e_shnum, strerror(errno));
}
}
static void add_reloc(struct relocs *r, uint32_t offset, unsigned type)
{
/* Relocation representation in binary table:
* |76543210|76543210|76543210|76543210|
* | Type | offset from _text >> 2 |
*/
offset >>= 2;
if (offset > 0x00FFFFFF)
die("Kernel image exceeds maximum size for relocation!\n");
offset = (offset & 0x00FFFFFF) | ((type & 0xFF) << 24);
if (r->count == r->size) {
unsigned long newsize = r->size + 50000;
void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
if (!mem)
die("realloc failed\n");
r->offset = mem;
r->size = newsize;
}
r->offset[r->count++] = offset;
}
static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
Elf_Sym *sym, const char *symname))
{
int i;
/* Walk through the relocations */
for (i = 0; i < ehdr.e_shnum; i++) {
char *sym_strtab;
Elf_Sym *sh_symtab;
struct section *sec_applies, *sec_symtab;
int j;
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_REL_TYPE)
continue;
sec_symtab = sec->link;
sec_applies = &secs[sec->shdr.sh_info];
if (!(sec_applies->shdr.sh_flags & SHF_ALLOC))
continue;
sh_symtab = sec_symtab->symtab;
sym_strtab = sec_symtab->link->strtab;
for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
Elf_Rel *rel = &sec->reltab[j];
Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
const char *symname = sym_name(sym_strtab, sym);
process(sec, rel, sym, symname);
}
}
}
static int do_reloc(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
const char *symname)
{
unsigned r_type = ELF_R_TYPE(rel->r_info);
unsigned bind = ELF_ST_BIND(sym->st_info);
if ((bind == STB_WEAK) && (sym->st_value == 0)) {
/* Don't relocate weak symbols without a target */
return 0;
}
if (regex_skip_reloc(symname))
return 0;
switch (r_type) {
case R_MIPS_NONE:
case R_MIPS_REL32:
case R_MIPS_PC16:
case R_MIPS_PC21_S2:
case R_MIPS_PC26_S2:
/*
* NONE can be ignored and PC relative relocations don't
* need to be adjusted.
*/
case R_MIPS_HIGHEST:
case R_MIPS_HIGHER:
/* We support relocating within the same 4Gb segment only,
* thus leaving the top 32bits unchanged
*/
case R_MIPS_LO16:
/* We support relocating by 64k jumps only
* thus leaving the bottom 16bits unchanged
*/
break;
case R_MIPS_64:
case R_MIPS_32:
case R_MIPS_26:
case R_MIPS_HI16:
add_reloc(&relocs, rel->r_offset, r_type);
break;
default:
die("Unsupported relocation type: %s (%d)\n",
rel_type(r_type), r_type);
break;
}
return 0;
}
static int write_reloc_as_bin(uint32_t v, FILE *f)
{
unsigned char buf[4];
v = cpu_to_elf32(v);
memcpy(buf, &v, sizeof(uint32_t));
return fwrite(buf, 1, 4, f);
}
static int write_reloc_as_text(uint32_t v, FILE *f)
{
int res;
res = fprintf(f, "\t.long 0x%08"PRIx32"\n", v);
if (res < 0)
return res;
else
return sizeof(uint32_t);
}
static void emit_relocs(int as_text, int as_bin, FILE *outf)
{
int i;
int (*write_reloc)(uint32_t, FILE *) = write_reloc_as_bin;
int size = 0;
int size_reserved;
struct section *sec_reloc;
sec_reloc = sec_lookup(".data.reloc");
if (!sec_reloc)
die("Could not find relocation section\n");
size_reserved = sec_reloc->shdr.sh_size;
/* Collect up the relocations */
walk_relocs(do_reloc);
/* Print the relocations */
if (as_text) {
/* Print the relocations in a form suitable that
* gas will like.
*/
printf(".section \".data.reloc\",\"a\"\n");
printf(".balign 4\n");
/* Output text to stdout */
write_reloc = write_reloc_as_text;
outf = stdout;
} else if (as_bin) {
/* Output raw binary to stdout */
outf = stdout;
} else {
/* Seek to offset of the relocation section.
* Each relocation is then written into the
* vmlinux kernel image.
*/
if (fseek(outf, sec_reloc->shdr.sh_offset, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
sec_reloc->shdr.sh_offset, strerror(errno));
}
}
for (i = 0; i < relocs.count; i++)
size += write_reloc(relocs.offset[i], outf);
/* Print a stop, but only if we've actually written some relocs */
if (size)
size += write_reloc(0, outf);
if (size > size_reserved)
/* Die, but suggest a value for CONFIG_RELOCATION_TABLE_SIZE
* which will fix this problem and allow a bit of headroom
* if more kernel features are enabled
*/
die("Relocations overflow available space!\n" \
"Please adjust CONFIG_RELOCATION_TABLE_SIZE " \
"to at least 0x%08x\n", (size + 0x1000) & ~0xFFF);
}
/*
* As an aid to debugging problems with different linkers
* print summary information about the relocs.
* Since different linkers tend to emit the sections in
* different orders we use the section names in the output.
*/
static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
const char *symname)
{
printf("%16s 0x%08x %16s %40s %16s\n",
sec_name(sec->shdr.sh_info),
(unsigned int)rel->r_offset,
rel_type(ELF_R_TYPE(rel->r_info)),
symname,
sec_name(sym->st_shndx));
return 0;
}
static void print_reloc_info(void)
{
printf("%16s %10s %16s %40s %16s\n",
"reloc section",
"offset",
"reloc type",
"symbol",
"symbol section");
walk_relocs(do_reloc_info);
}
#if ELF_BITS == 64
# define process process_64
#else
# define process process_32
#endif
void process(FILE *fp, int as_text, int as_bin,
int show_reloc_info, int keep_relocs)
{
regex_init();
read_ehdr(fp);
read_shdrs(fp);
read_strtabs(fp);
read_symtabs(fp);
read_relocs(fp);
if (show_reloc_info) {
print_reloc_info();
return;
}
emit_relocs(as_text, as_bin, fp);
if (!keep_relocs)
remove_relocs(fp);
}