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linux/scripts/mod/modpost.c
Anders Kaseorg 6845756b29 modpost: Update 64k section support for binutils 2.18.50 
Binutils 2.18.50 made a backwards-incompatible change in the way it
writes ELF objects with over 65280 sections, to improve conformance
with the ELF specification and interoperability with other ELF tools.
Specifically, it no longer adds 256 to section indices SHN_LORESERVE
and higher to skip over the reserved range SHN_LORESERVE through
SHN_HIRESERVE; those values are only considered special in the
st_shndx field, and not in other places where section indices are
stored.  See:

http://sourceware.org/bugzilla/show_bug.cgi?id=5900
http://groups.google.com/group/generic-abi/browse_thread/thread/e8bb63714b072e67/6c63738f12cc8a17

Signed-off-by: Anders Kaseorg <andersk@ksplice.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-19 16:55:28 +09:30

2165 lines
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/* Postprocess module symbol versions
*
* Copyright 2003 Kai Germaschewski
* Copyright 2002-2004 Rusty Russell, IBM Corporation
* Copyright 2006-2008 Sam Ravnborg
* Based in part on module-init-tools/depmod.c,file2alias
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*
* Usage: modpost vmlinux module1.o module2.o ...
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include "modpost.h"
#include "../../include/generated/autoconf.h"
#include "../../include/linux/license.h"
/* Some toolchains use a `_' prefix for all user symbols. */
#ifdef CONFIG_SYMBOL_PREFIX
#define MODULE_SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX
#else
#define MODULE_SYMBOL_PREFIX ""
#endif
/* Are we using CONFIG_MODVERSIONS? */
int modversions = 0;
/* Warn about undefined symbols? (do so if we have vmlinux) */
int have_vmlinux = 0;
/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
static int all_versions = 0;
/* If we are modposting external module set to 1 */
static int external_module = 0;
/* Warn about section mismatch in vmlinux if set to 1 */
static int vmlinux_section_warnings = 1;
/* Only warn about unresolved symbols */
static int warn_unresolved = 0;
/* How a symbol is exported */
static int sec_mismatch_count = 0;
static int sec_mismatch_verbose = 1;
enum export {
export_plain, export_unused, export_gpl,
export_unused_gpl, export_gpl_future, export_unknown
};
#define PRINTF __attribute__ ((format (printf, 1, 2)))
PRINTF void fatal(const char *fmt, ...)
{
va_list arglist;
fprintf(stderr, "FATAL: ");
va_start(arglist, fmt);
vfprintf(stderr, fmt, arglist);
va_end(arglist);
exit(1);
}
PRINTF void warn(const char *fmt, ...)
{
va_list arglist;
fprintf(stderr, "WARNING: ");
va_start(arglist, fmt);
vfprintf(stderr, fmt, arglist);
va_end(arglist);
}
PRINTF void merror(const char *fmt, ...)
{
va_list arglist;
fprintf(stderr, "ERROR: ");
va_start(arglist, fmt);
vfprintf(stderr, fmt, arglist);
va_end(arglist);
}
static int is_vmlinux(const char *modname)
{
const char *myname;
myname = strrchr(modname, '/');
if (myname)
myname++;
else
myname = modname;
return (strcmp(myname, "vmlinux") == 0) ||
(strcmp(myname, "vmlinux.o") == 0);
}
void *do_nofail(void *ptr, const char *expr)
{
if (!ptr)
fatal("modpost: Memory allocation failure: %s.\n", expr);
return ptr;
}
/* A list of all modules we processed */
static struct module *modules;
static struct module *find_module(char *modname)
{
struct module *mod;
for (mod = modules; mod; mod = mod->next)
if (strcmp(mod->name, modname) == 0)
break;
return mod;
}
static struct module *new_module(char *modname)
{
struct module *mod;
char *p, *s;
mod = NOFAIL(malloc(sizeof(*mod)));
memset(mod, 0, sizeof(*mod));
p = NOFAIL(strdup(modname));
/* strip trailing .o */
s = strrchr(p, '.');
if (s != NULL)
if (strcmp(s, ".o") == 0)
*s = '\0';
/* add to list */
mod->name = p;
mod->gpl_compatible = -1;
mod->next = modules;
modules = mod;
return mod;
}
/* A hash of all exported symbols,
* struct symbol is also used for lists of unresolved symbols */
#define SYMBOL_HASH_SIZE 1024
struct symbol {
struct symbol *next;
struct module *module;
unsigned int crc;
int crc_valid;
unsigned int weak:1;
unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
unsigned int kernel:1; /* 1 if symbol is from kernel
* (only for external modules) **/
unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
enum export export; /* Type of export */
char name[0];
};
static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
/* This is based on the hash agorithm from gdbm, via tdb */
static inline unsigned int tdb_hash(const char *name)
{
unsigned value; /* Used to compute the hash value. */
unsigned i; /* Used to cycle through random values. */
/* Set the initial value from the key size. */
for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
return (1103515243 * value + 12345);
}
/**
* Allocate a new symbols for use in the hash of exported symbols or
* the list of unresolved symbols per module
**/
static struct symbol *alloc_symbol(const char *name, unsigned int weak,
struct symbol *next)
{
struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
memset(s, 0, sizeof(*s));
strcpy(s->name, name);
s->weak = weak;
s->next = next;
return s;
}
/* For the hash of exported symbols */
static struct symbol *new_symbol(const char *name, struct module *module,
enum export export)
{
unsigned int hash;
struct symbol *new;
hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
new->module = module;
new->export = export;
return new;
}
static struct symbol *find_symbol(const char *name)
{
struct symbol *s;
/* For our purposes, .foo matches foo. PPC64 needs this. */
if (name[0] == '.')
name++;
for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
if (strcmp(s->name, name) == 0)
return s;
}
return NULL;
}
static struct {
const char *str;
enum export export;
} export_list[] = {
{ .str = "EXPORT_SYMBOL", .export = export_plain },
{ .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
{ .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
{ .str = "(unknown)", .export = export_unknown },
};
static const char *export_str(enum export ex)
{
return export_list[ex].str;
}
static enum export export_no(const char *s)
{
int i;
if (!s)
return export_unknown;
for (i = 0; export_list[i].export != export_unknown; i++) {
if (strcmp(export_list[i].str, s) == 0)
return export_list[i].export;
}
return export_unknown;
}
static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
{
if (sec == elf->export_sec)
return export_plain;
else if (sec == elf->export_unused_sec)
return export_unused;
else if (sec == elf->export_gpl_sec)
return export_gpl;
else if (sec == elf->export_unused_gpl_sec)
return export_unused_gpl;
else if (sec == elf->export_gpl_future_sec)
return export_gpl_future;
else
return export_unknown;
}
/**
* Add an exported symbol - it may have already been added without a
* CRC, in this case just update the CRC
**/
static struct symbol *sym_add_exported(const char *name, struct module *mod,
enum export export)
{
struct symbol *s = find_symbol(name);
if (!s) {
s = new_symbol(name, mod, export);
} else {
if (!s->preloaded) {
warn("%s: '%s' exported twice. Previous export "
"was in %s%s\n", mod->name, name,
s->module->name,
is_vmlinux(s->module->name) ?"":".ko");
} else {
/* In case Modules.symvers was out of date */
s->module = mod;
}
}
s->preloaded = 0;
s->vmlinux = is_vmlinux(mod->name);
s->kernel = 0;
s->export = export;
return s;
}
static void sym_update_crc(const char *name, struct module *mod,
unsigned int crc, enum export export)
{
struct symbol *s = find_symbol(name);
if (!s)
s = new_symbol(name, mod, export);
s->crc = crc;
s->crc_valid = 1;
}
void *grab_file(const char *filename, unsigned long *size)
{
struct stat st;
void *map;
int fd;
fd = open(filename, O_RDONLY);
if (fd < 0 || fstat(fd, &st) != 0)
return NULL;
*size = st.st_size;
map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
close(fd);
if (map == MAP_FAILED)
return NULL;
return map;
}
/**
* Return a copy of the next line in a mmap'ed file.
* spaces in the beginning of the line is trimmed away.
* Return a pointer to a static buffer.
**/
char *get_next_line(unsigned long *pos, void *file, unsigned long size)
{
static char line[4096];
int skip = 1;
size_t len = 0;
signed char *p = (signed char *)file + *pos;
char *s = line;
for (; *pos < size ; (*pos)++) {
if (skip && isspace(*p)) {
p++;
continue;
}
skip = 0;
if (*p != '\n' && (*pos < size)) {
len++;
*s++ = *p++;
if (len > 4095)
break; /* Too long, stop */
} else {
/* End of string */
*s = '\0';
return line;
}
}
/* End of buffer */
return NULL;
}
void release_file(void *file, unsigned long size)
{
munmap(file, size);
}
static int parse_elf(struct elf_info *info, const char *filename)
{
unsigned int i;
Elf_Ehdr *hdr;
Elf_Shdr *sechdrs;
Elf_Sym *sym;
const char *secstrings;
unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
hdr = grab_file(filename, &info->size);
if (!hdr) {
perror(filename);
exit(1);
}
info->hdr = hdr;
if (info->size < sizeof(*hdr)) {
/* file too small, assume this is an empty .o file */
return 0;
}
/* Is this a valid ELF file? */
if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
(hdr->e_ident[EI_MAG1] != ELFMAG1) ||
(hdr->e_ident[EI_MAG2] != ELFMAG2) ||
(hdr->e_ident[EI_MAG3] != ELFMAG3)) {
/* Not an ELF file - silently ignore it */
return 0;
}
/* Fix endianness in ELF header */
hdr->e_type = TO_NATIVE(hdr->e_type);
hdr->e_machine = TO_NATIVE(hdr->e_machine);
hdr->e_version = TO_NATIVE(hdr->e_version);
hdr->e_entry = TO_NATIVE(hdr->e_entry);
hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
hdr->e_flags = TO_NATIVE(hdr->e_flags);
hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
sechdrs = (void *)hdr + hdr->e_shoff;
info->sechdrs = sechdrs;
/* Check if file offset is correct */
if (hdr->e_shoff > info->size) {
fatal("section header offset=%lu in file '%s' is bigger than "
"filesize=%lu\n", (unsigned long)hdr->e_shoff,
filename, info->size);
return 0;
}
if (hdr->e_shnum == SHN_UNDEF) {
/*
* There are more than 64k sections,
* read count from .sh_size.
*/
info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
}
else {
info->num_sections = hdr->e_shnum;
}
if (hdr->e_shstrndx == SHN_XINDEX) {
info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
}
else {
info->secindex_strings = hdr->e_shstrndx;
}
/* Fix endianness in section headers */
for (i = 0; i < info->num_sections; i++) {
sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
}
/* Find symbol table. */
secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
for (i = 1; i < info->num_sections; i++) {
const char *secname;
int nobits = sechdrs[i].sh_type == SHT_NOBITS;
if (!nobits && sechdrs[i].sh_offset > info->size) {
fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
"sizeof(*hrd)=%zu\n", filename,
(unsigned long)sechdrs[i].sh_offset,
sizeof(*hdr));
return 0;
}
secname = secstrings + sechdrs[i].sh_name;
if (strcmp(secname, ".modinfo") == 0) {
if (nobits)
fatal("%s has NOBITS .modinfo\n", filename);
info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
info->modinfo_len = sechdrs[i].sh_size;
} else if (strcmp(secname, "__ksymtab") == 0)
info->export_sec = i;
else if (strcmp(secname, "__ksymtab_unused") == 0)
info->export_unused_sec = i;
else if (strcmp(secname, "__ksymtab_gpl") == 0)
info->export_gpl_sec = i;
else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
info->export_unused_gpl_sec = i;
else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
info->export_gpl_future_sec = i;
if (sechdrs[i].sh_type == SHT_SYMTAB) {
unsigned int sh_link_idx;
symtab_idx = i;
info->symtab_start = (void *)hdr +
sechdrs[i].sh_offset;
info->symtab_stop = (void *)hdr +
sechdrs[i].sh_offset + sechdrs[i].sh_size;
sh_link_idx = sechdrs[i].sh_link;
info->strtab = (void *)hdr +
sechdrs[sh_link_idx].sh_offset;
}
/* 32bit section no. table? ("more than 64k sections") */
if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
symtab_shndx_idx = i;
info->symtab_shndx_start = (void *)hdr +
sechdrs[i].sh_offset;
info->symtab_shndx_stop = (void *)hdr +
sechdrs[i].sh_offset + sechdrs[i].sh_size;
}
}
if (!info->symtab_start)
fatal("%s has no symtab?\n", filename);
/* Fix endianness in symbols */
for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
sym->st_shndx = TO_NATIVE(sym->st_shndx);
sym->st_name = TO_NATIVE(sym->st_name);
sym->st_value = TO_NATIVE(sym->st_value);
sym->st_size = TO_NATIVE(sym->st_size);
}
if (symtab_shndx_idx != ~0U) {
Elf32_Word *p;
if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
filename, sechdrs[symtab_shndx_idx].sh_link,
symtab_idx);
/* Fix endianness */
for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
p++)
*p = TO_NATIVE(*p);
}
return 1;
}
static void parse_elf_finish(struct elf_info *info)
{
release_file(info->hdr, info->size);
}
static int ignore_undef_symbol(struct elf_info *info, const char *symname)
{
/* ignore __this_module, it will be resolved shortly */
if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
return 1;
/* ignore global offset table */
if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
return 1;
if (info->hdr->e_machine == EM_PPC)
/* Special register function linked on all modules during final link of .ko */
if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0)
return 1;
if (info->hdr->e_machine == EM_PPC64)
/* Special register function linked on all modules during final link of .ko */
if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0)
return 1;
/* Do not ignore this symbol */
return 0;
}
#define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
#define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
static void handle_modversions(struct module *mod, struct elf_info *info,
Elf_Sym *sym, const char *symname)
{
unsigned int crc;
enum export export = export_from_sec(info, get_secindex(info, sym));
switch (sym->st_shndx) {
case SHN_COMMON:
warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
break;
case SHN_ABS:
/* CRC'd symbol */
if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
crc = (unsigned int) sym->st_value;
sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
export);
}
break;
case SHN_UNDEF:
/* undefined symbol */
if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
ELF_ST_BIND(sym->st_info) != STB_WEAK)
break;
if (ignore_undef_symbol(info, symname))
break;
/* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
#if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
/* add compatibility with older glibc */
#ifndef STT_SPARC_REGISTER
#define STT_SPARC_REGISTER STT_REGISTER
#endif
if (info->hdr->e_machine == EM_SPARC ||
info->hdr->e_machine == EM_SPARCV9) {
/* Ignore register directives. */
if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
break;
if (symname[0] == '.') {
char *munged = strdup(symname);
munged[0] = '_';
munged[1] = toupper(munged[1]);
symname = munged;
}
}
#endif
if (memcmp(symname, MODULE_SYMBOL_PREFIX,
strlen(MODULE_SYMBOL_PREFIX)) == 0) {
mod->unres =
alloc_symbol(symname +
strlen(MODULE_SYMBOL_PREFIX),
ELF_ST_BIND(sym->st_info) == STB_WEAK,
mod->unres);
}
break;
default:
/* All exported symbols */
if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
export);
}
if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
mod->has_init = 1;
if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
mod->has_cleanup = 1;
break;
}
}
/**
* Parse tag=value strings from .modinfo section
**/
static char *next_string(char *string, unsigned long *secsize)
{
/* Skip non-zero chars */
while (string[0]) {
string++;
if ((*secsize)-- <= 1)
return NULL;
}
/* Skip any zero padding. */
while (!string[0]) {
string++;
if ((*secsize)-- <= 1)
return NULL;
}
return string;
}
static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
const char *tag, char *info)
{
char *p;
unsigned int taglen = strlen(tag);
unsigned long size = modinfo_len;
if (info) {
size -= info - (char *)modinfo;
modinfo = next_string(info, &size);
}
for (p = modinfo; p; p = next_string(p, &size)) {
if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
return p + taglen + 1;
}
return NULL;
}
static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
const char *tag)
{
return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
}
/**
* Test if string s ends in string sub
* return 0 if match
**/
static int strrcmp(const char *s, const char *sub)
{
int slen, sublen;
if (!s || !sub)
return 1;
slen = strlen(s);
sublen = strlen(sub);
if ((slen == 0) || (sublen == 0))
return 1;
if (sublen > slen)
return 1;
return memcmp(s + slen - sublen, sub, sublen);
}
static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
{
if (sym)
return elf->strtab + sym->st_name;
else
return "(unknown)";
}
static const char *sec_name(struct elf_info *elf, int secindex)
{
Elf_Shdr *sechdrs = elf->sechdrs;
return (void *)elf->hdr +
elf->sechdrs[elf->secindex_strings].sh_offset +
sechdrs[secindex].sh_name;
}
static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
{
return (void *)elf->hdr +
elf->sechdrs[elf->secindex_strings].sh_offset +
sechdr->sh_name;
}
/* if sym is empty or point to a string
* like ".[0-9]+" then return 1.
* This is the optional prefix added by ld to some sections
*/
static int number_prefix(const char *sym)
{
if (*sym++ == '\0')
return 1;
if (*sym != '.')
return 0;
do {
char c = *sym++;
if (c < '0' || c > '9')
return 0;
} while (*sym);
return 1;
}
/* The pattern is an array of simple patterns.
* "foo" will match an exact string equal to "foo"
* "*foo" will match a string that ends with "foo"
* "foo*" will match a string that begins with "foo"
* "foo$" will match a string equal to "foo" or "foo.1"
* where the '1' can be any number including several digits.
* The $ syntax is for sections where ld append a dot number
* to make section name unique.
*/
static int match(const char *sym, const char * const pat[])
{
const char *p;
while (*pat) {
p = *pat++;
const char *endp = p + strlen(p) - 1;
/* "*foo" */
if (*p == '*') {
if (strrcmp(sym, p + 1) == 0)
return 1;
}
/* "foo*" */
else if (*endp == '*') {
if (strncmp(sym, p, strlen(p) - 1) == 0)
return 1;
}
/* "foo$" */
else if (*endp == '$') {
if (strncmp(sym, p, strlen(p) - 1) == 0) {
if (number_prefix(sym + strlen(p) - 1))
return 1;
}
}
/* no wildcards */
else {
if (strcmp(p, sym) == 0)
return 1;
}
}
/* no match */
return 0;
}
/* sections that we do not want to do full section mismatch check on */
static const char *section_white_list[] =
{
".comment*",
".debug*",
".zdebug*", /* Compressed debug sections. */
".GCC-command-line", /* mn10300 */
".mdebug*", /* alpha, score, mips etc. */
".pdr", /* alpha, score, mips etc. */
".stab*",
".note*",
".got*",
".toc*",
NULL
};
/*
* This is used to find sections missing the SHF_ALLOC flag.
* The cause of this is often a section specified in assembler
* without "ax" / "aw".
*/
static void check_section(const char *modname, struct elf_info *elf,
Elf_Shdr *sechdr)
{
const char *sec = sech_name(elf, sechdr);
if (sechdr->sh_type == SHT_PROGBITS &&
!(sechdr->sh_flags & SHF_ALLOC) &&
!match(sec, section_white_list)) {
warn("%s (%s): unexpected non-allocatable section.\n"
"Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
"Note that for example <linux/init.h> contains\n"
"section definitions for use in .S files.\n\n",
modname, sec);
}
}
#define ALL_INIT_DATA_SECTIONS \
".init.setup$", ".init.rodata$", \
".devinit.rodata$", ".cpuinit.rodata$", ".meminit.rodata$" \
".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
#define ALL_EXIT_DATA_SECTIONS \
".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
#define ALL_INIT_TEXT_SECTIONS \
".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
#define ALL_EXIT_TEXT_SECTIONS \
".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
#define ALL_XXXINIT_SECTIONS DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, \
MEM_INIT_SECTIONS
#define ALL_XXXEXIT_SECTIONS DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, \
MEM_EXIT_SECTIONS
#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
#define DATA_SECTIONS ".data$", ".data.rel$"
#define TEXT_SECTIONS ".text$"
#define INIT_SECTIONS ".init.*"
#define DEV_INIT_SECTIONS ".devinit.*"
#define CPU_INIT_SECTIONS ".cpuinit.*"
#define MEM_INIT_SECTIONS ".meminit.*"
#define EXIT_SECTIONS ".exit.*"
#define DEV_EXIT_SECTIONS ".devexit.*"
#define CPU_EXIT_SECTIONS ".cpuexit.*"
#define MEM_EXIT_SECTIONS ".memexit.*"
/* init data sections */
static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
/* all init sections */
static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
/* All init and exit sections (code + data) */
static const char *init_exit_sections[] =
{ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
/* data section */
static const char *data_sections[] = { DATA_SECTIONS, NULL };
/* symbols in .data that may refer to init/exit sections */
#define DEFAULT_SYMBOL_WHITE_LIST \
"*driver", \
"*_template", /* scsi uses *_template a lot */ \
"*_timer", /* arm uses ops structures named _timer a lot */ \
"*_sht", /* scsi also used *_sht to some extent */ \
"*_ops", \
"*_probe", \
"*_probe_one", \
"*_console"
static const char *head_sections[] = { ".head.text*", NULL };
static const char *linker_symbols[] =
{ "__init_begin", "_sinittext", "_einittext", NULL };
enum mismatch {
TEXT_TO_ANY_INIT,
DATA_TO_ANY_INIT,
TEXT_TO_ANY_EXIT,
DATA_TO_ANY_EXIT,
XXXINIT_TO_SOME_INIT,
XXXEXIT_TO_SOME_EXIT,
ANY_INIT_TO_ANY_EXIT,
ANY_EXIT_TO_ANY_INIT,
EXPORT_TO_INIT_EXIT,
};
struct sectioncheck {
const char *fromsec[20];
const char *tosec[20];
enum mismatch mismatch;
const char *symbol_white_list[20];
};
const struct sectioncheck sectioncheck[] = {
/* Do not reference init/exit code/data from
* normal code and data
*/
{
.fromsec = { TEXT_SECTIONS, NULL },
.tosec = { ALL_INIT_SECTIONS, NULL },
.mismatch = TEXT_TO_ANY_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { DATA_SECTIONS, NULL },
.tosec = { ALL_XXXINIT_SECTIONS, NULL },
.mismatch = DATA_TO_ANY_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { DATA_SECTIONS, NULL },
.tosec = { INIT_SECTIONS, NULL },
.mismatch = DATA_TO_ANY_INIT,
.symbol_white_list = {
"*_template", "*_timer", "*_sht", "*_ops",
"*_probe", "*_probe_one", "*_console", NULL
},
},
{
.fromsec = { TEXT_SECTIONS, NULL },
.tosec = { ALL_EXIT_SECTIONS, NULL },
.mismatch = TEXT_TO_ANY_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { DATA_SECTIONS, NULL },
.tosec = { ALL_EXIT_SECTIONS, NULL },
.mismatch = DATA_TO_ANY_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not reference init code/data from devinit/cpuinit/meminit code/data */
{
.fromsec = { ALL_XXXINIT_SECTIONS, NULL },
.tosec = { INIT_SECTIONS, NULL },
.mismatch = XXXINIT_TO_SOME_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not reference cpuinit code/data from meminit code/data */
{
.fromsec = { MEM_INIT_SECTIONS, NULL },
.tosec = { CPU_INIT_SECTIONS, NULL },
.mismatch = XXXINIT_TO_SOME_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not reference meminit code/data from cpuinit code/data */
{
.fromsec = { CPU_INIT_SECTIONS, NULL },
.tosec = { MEM_INIT_SECTIONS, NULL },
.mismatch = XXXINIT_TO_SOME_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
{
.fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
.tosec = { EXIT_SECTIONS, NULL },
.mismatch = XXXEXIT_TO_SOME_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not reference cpuexit code/data from memexit code/data */
{
.fromsec = { MEM_EXIT_SECTIONS, NULL },
.tosec = { CPU_EXIT_SECTIONS, NULL },
.mismatch = XXXEXIT_TO_SOME_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not reference memexit code/data from cpuexit code/data */
{
.fromsec = { CPU_EXIT_SECTIONS, NULL },
.tosec = { MEM_EXIT_SECTIONS, NULL },
.mismatch = XXXEXIT_TO_SOME_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not use exit code/data from init code */
{
.fromsec = { ALL_INIT_SECTIONS, NULL },
.tosec = { ALL_EXIT_SECTIONS, NULL },
.mismatch = ANY_INIT_TO_ANY_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not use init code/data from exit code */
{
.fromsec = { ALL_EXIT_SECTIONS, NULL },
.tosec = { ALL_INIT_SECTIONS, NULL },
.mismatch = ANY_EXIT_TO_ANY_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not export init/exit functions or data */
{
.fromsec = { "__ksymtab*", NULL },
.tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
.mismatch = EXPORT_TO_INIT_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
}
};
static const struct sectioncheck *section_mismatch(
const char *fromsec, const char *tosec)
{
int i;
int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
const struct sectioncheck *check = &sectioncheck[0];
for (i = 0; i < elems; i++) {
if (match(fromsec, check->fromsec) &&
match(tosec, check->tosec))
return check;
check++;
}
return NULL;
}
/**
* Whitelist to allow certain references to pass with no warning.
*
* Pattern 1:
* If a module parameter is declared __initdata and permissions=0
* then this is legal despite the warning generated.
* We cannot see value of permissions here, so just ignore
* this pattern.
* The pattern is identified by:
* tosec = .init.data
* fromsec = .data*
* atsym =__param*
*
* Pattern 1a:
* module_param_call() ops can refer to __init set function if permissions=0
* The pattern is identified by:
* tosec = .init.text
* fromsec = .data*
* atsym = __param_ops_*
*
* Pattern 2:
* Many drivers utilise a *driver container with references to
* add, remove, probe functions etc.
* These functions may often be marked __devinit and we do not want to
* warn here.
* the pattern is identified by:
* tosec = init or exit section
* fromsec = data section
* atsym = *driver, *_template, *_sht, *_ops, *_probe,
* *probe_one, *_console, *_timer
*
* Pattern 3:
* Whitelist all references from .head.text to any init section
*
* Pattern 4:
* Some symbols belong to init section but still it is ok to reference
* these from non-init sections as these symbols don't have any memory
* allocated for them and symbol address and value are same. So even
* if init section is freed, its ok to reference those symbols.
* For ex. symbols marking the init section boundaries.
* This pattern is identified by
* refsymname = __init_begin, _sinittext, _einittext
*
**/
static int secref_whitelist(const struct sectioncheck *mismatch,
const char *fromsec, const char *fromsym,
const char *tosec, const char *tosym)
{
/* Check for pattern 1 */
if (match(tosec, init_data_sections) &&
match(fromsec, data_sections) &&
(strncmp(fromsym, "__param", strlen("__param")) == 0))
return 0;
/* Check for pattern 1a */
if (strcmp(tosec, ".init.text") == 0 &&
match(fromsec, data_sections) &&
(strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
return 0;
/* Check for pattern 2 */
if (match(tosec, init_exit_sections) &&
match(fromsec, data_sections) &&
match(fromsym, mismatch->symbol_white_list))
return 0;
/* Check for pattern 3 */
if (match(fromsec, head_sections) &&
match(tosec, init_sections))
return 0;
/* Check for pattern 4 */
if (match(tosym, linker_symbols))
return 0;
return 1;
}
/**
* Find symbol based on relocation record info.
* In some cases the symbol supplied is a valid symbol so
* return refsym. If st_name != 0 we assume this is a valid symbol.
* In other cases the symbol needs to be looked up in the symbol table
* based on section and address.
* **/
static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
Elf_Sym *relsym)
{
Elf_Sym *sym;
Elf_Sym *near = NULL;
Elf64_Sword distance = 20;
Elf64_Sword d;
unsigned int relsym_secindex;
if (relsym->st_name != 0)
return relsym;
relsym_secindex = get_secindex(elf, relsym);
for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
if (get_secindex(elf, sym) != relsym_secindex)
continue;
if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
continue;
if (sym->st_value == addr)
return sym;
/* Find a symbol nearby - addr are maybe negative */
d = sym->st_value - addr;
if (d < 0)
d = addr - sym->st_value;
if (d < distance) {
distance = d;
near = sym;
}
}
/* We need a close match */
if (distance < 20)
return near;
else
return NULL;
}
static inline int is_arm_mapping_symbol(const char *str)
{
return str[0] == '$' && strchr("atd", str[1])
&& (str[2] == '\0' || str[2] == '.');
}
/*
* If there's no name there, ignore it; likewise, ignore it if it's
* one of the magic symbols emitted used by current ARM tools.
*
* Otherwise if find_symbols_between() returns those symbols, they'll
* fail the whitelist tests and cause lots of false alarms ... fixable
* only by merging __exit and __init sections into __text, bloating
* the kernel (which is especially evil on embedded platforms).
*/
static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
{
const char *name = elf->strtab + sym->st_name;
if (!name || !strlen(name))
return 0;
return !is_arm_mapping_symbol(name);
}
/*
* Find symbols before or equal addr and after addr - in the section sec.
* If we find two symbols with equal offset prefer one with a valid name.
* The ELF format may have a better way to detect what type of symbol
* it is, but this works for now.
**/
static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
const char *sec)
{
Elf_Sym *sym;
Elf_Sym *near = NULL;
Elf_Addr distance = ~0;
for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
const char *symsec;
if (is_shndx_special(sym->st_shndx))
continue;
symsec = sec_name(elf, get_secindex(elf, sym));
if (strcmp(symsec, sec) != 0)
continue;
if (!is_valid_name(elf, sym))
continue;
if (sym->st_value <= addr) {
if ((addr - sym->st_value) < distance) {
distance = addr - sym->st_value;
near = sym;
} else if ((addr - sym->st_value) == distance) {
near = sym;
}
}
}
return near;
}
/*
* Convert a section name to the function/data attribute
* .init.text => __init
* .cpuinit.data => __cpudata
* .memexitconst => __memconst
* etc.
*
* The memory of returned value has been allocated on a heap. The user of this
* method should free it after usage.
*/
static char *sec2annotation(const char *s)
{
if (match(s, init_exit_sections)) {
char *p = malloc(20);
char *r = p;
*p++ = '_';
*p++ = '_';
if (*s == '.')
s++;
while (*s && *s != '.')
*p++ = *s++;
*p = '\0';
if (*s == '.')
s++;
if (strstr(s, "rodata") != NULL)
strcat(p, "const ");
else if (strstr(s, "data") != NULL)
strcat(p, "data ");
else
strcat(p, " ");
return r;
} else {
return strdup("");
}
}
static int is_function(Elf_Sym *sym)
{
if (sym)
return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
else
return -1;
}
static void print_section_list(const char * const list[20])
{
const char *const *s = list;
while (*s) {
fprintf(stderr, "%s", *s);
s++;
if (*s)
fprintf(stderr, ", ");
}
fprintf(stderr, "\n");
}
/*
* Print a warning about a section mismatch.
* Try to find symbols near it so user can find it.
* Check whitelist before warning - it may be a false positive.
*/
static void report_sec_mismatch(const char *modname,
const struct sectioncheck *mismatch,
const char *fromsec,
unsigned long long fromaddr,
const char *fromsym,
int from_is_func,
const char *tosec, const char *tosym,
int to_is_func)
{
const char *from, *from_p;
const char *to, *to_p;
char *prl_from;
char *prl_to;
switch (from_is_func) {
case 0: from = "variable"; from_p = ""; break;
case 1: from = "function"; from_p = "()"; break;
default: from = "(unknown reference)"; from_p = ""; break;
}
switch (to_is_func) {
case 0: to = "variable"; to_p = ""; break;
case 1: to = "function"; to_p = "()"; break;
default: to = "(unknown reference)"; to_p = ""; break;
}
sec_mismatch_count++;
if (!sec_mismatch_verbose)
return;
warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
"to the %s %s:%s%s\n",
modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
tosym, to_p);
switch (mismatch->mismatch) {
case TEXT_TO_ANY_INIT:
prl_from = sec2annotation(fromsec);
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The function %s%s() references\n"
"the %s %s%s%s.\n"
"This is often because %s lacks a %s\n"
"annotation or the annotation of %s is wrong.\n",
prl_from, fromsym,
to, prl_to, tosym, to_p,
fromsym, prl_to, tosym);
free(prl_from);
free(prl_to);
break;
case DATA_TO_ANY_INIT: {
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The variable %s references\n"
"the %s %s%s%s\n"
"If the reference is valid then annotate the\n"
"variable with __init* or __refdata (see linux/init.h) "
"or name the variable:\n",
fromsym, to, prl_to, tosym, to_p);
print_section_list(mismatch->symbol_white_list);
free(prl_to);
break;
}
case TEXT_TO_ANY_EXIT:
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The function %s() references a %s in an exit section.\n"
"Often the %s %s%s has valid usage outside the exit section\n"
"and the fix is to remove the %sannotation of %s.\n",
fromsym, to, to, tosym, to_p, prl_to, tosym);
free(prl_to);
break;
case DATA_TO_ANY_EXIT: {
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The variable %s references\n"
"the %s %s%s%s\n"
"If the reference is valid then annotate the\n"
"variable with __exit* (see linux/init.h) or "
"name the variable:\n",
fromsym, to, prl_to, tosym, to_p);
print_section_list(mismatch->symbol_white_list);
free(prl_to);
break;
}
case XXXINIT_TO_SOME_INIT:
case XXXEXIT_TO_SOME_EXIT:
prl_from = sec2annotation(fromsec);
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The %s %s%s%s references\n"
"a %s %s%s%s.\n"
"If %s is only used by %s then\n"
"annotate %s with a matching annotation.\n",
from, prl_from, fromsym, from_p,
to, prl_to, tosym, to_p,
tosym, fromsym, tosym);
free(prl_from);
free(prl_to);
break;
case ANY_INIT_TO_ANY_EXIT:
prl_from = sec2annotation(fromsec);
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The %s %s%s%s references\n"
"a %s %s%s%s.\n"
"This is often seen when error handling "
"in the init function\n"
"uses functionality in the exit path.\n"
"The fix is often to remove the %sannotation of\n"
"%s%s so it may be used outside an exit section.\n",
from, prl_from, fromsym, from_p,
to, prl_to, tosym, to_p,
prl_to, tosym, to_p);
free(prl_from);
free(prl_to);
break;
case ANY_EXIT_TO_ANY_INIT:
prl_from = sec2annotation(fromsec);
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The %s %s%s%s references\n"
"a %s %s%s%s.\n"
"This is often seen when error handling "
"in the exit function\n"
"uses functionality in the init path.\n"
"The fix is often to remove the %sannotation of\n"
"%s%s so it may be used outside an init section.\n",
from, prl_from, fromsym, from_p,
to, prl_to, tosym, to_p,
prl_to, tosym, to_p);
free(prl_from);
free(prl_to);
break;
case EXPORT_TO_INIT_EXIT:
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The symbol %s is exported and annotated %s\n"
"Fix this by removing the %sannotation of %s "
"or drop the export.\n",
tosym, prl_to, prl_to, tosym);
free(prl_to);
break;
}
fprintf(stderr, "\n");
}
static void check_section_mismatch(const char *modname, struct elf_info *elf,
Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
{
const char *tosec;
const struct sectioncheck *mismatch;
tosec = sec_name(elf, get_secindex(elf, sym));
mismatch = section_mismatch(fromsec, tosec);
if (mismatch) {
Elf_Sym *to;
Elf_Sym *from;
const char *tosym;
const char *fromsym;
from = find_elf_symbol2(elf, r->r_offset, fromsec);
fromsym = sym_name(elf, from);
to = find_elf_symbol(elf, r->r_addend, sym);
tosym = sym_name(elf, to);
/* check whitelist - we may ignore it */
if (secref_whitelist(mismatch,
fromsec, fromsym, tosec, tosym)) {
report_sec_mismatch(modname, mismatch,
fromsec, r->r_offset, fromsym,
is_function(from), tosec, tosym,
is_function(to));
}
}
}
static unsigned int *reloc_location(struct elf_info *elf,
Elf_Shdr *sechdr, Elf_Rela *r)
{
Elf_Shdr *sechdrs = elf->sechdrs;
int section = sechdr->sh_info;
return (void *)elf->hdr + sechdrs[section].sh_offset +
r->r_offset;
}
static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
{
unsigned int r_typ = ELF_R_TYPE(r->r_info);
unsigned int *location = reloc_location(elf, sechdr, r);
switch (r_typ) {
case R_386_32:
r->r_addend = TO_NATIVE(*location);
break;
case R_386_PC32:
r->r_addend = TO_NATIVE(*location) + 4;
/* For CONFIG_RELOCATABLE=y */
if (elf->hdr->e_type == ET_EXEC)
r->r_addend += r->r_offset;
break;
}
return 0;
}
static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
{
unsigned int r_typ = ELF_R_TYPE(r->r_info);
switch (r_typ) {
case R_ARM_ABS32:
/* From ARM ABI: (S + A) | T */
r->r_addend = (int)(long)
(elf->symtab_start + ELF_R_SYM(r->r_info));
break;
case R_ARM_PC24:
/* From ARM ABI: ((S + A) | T) - P */
r->r_addend = (int)(long)(elf->hdr +
sechdr->sh_offset +
(r->r_offset - sechdr->sh_addr));
break;
default:
return 1;
}
return 0;
}
static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
{
unsigned int r_typ = ELF_R_TYPE(r->r_info);
unsigned int *location = reloc_location(elf, sechdr, r);
unsigned int inst;
if (r_typ == R_MIPS_HI16)
return 1; /* skip this */
inst = TO_NATIVE(*location);
switch (r_typ) {
case R_MIPS_LO16:
r->r_addend = inst & 0xffff;
break;
case R_MIPS_26:
r->r_addend = (inst & 0x03ffffff) << 2;
break;
case R_MIPS_32:
r->r_addend = inst;
break;
}
return 0;
}
static void section_rela(const char *modname, struct elf_info *elf,
Elf_Shdr *sechdr)
{
Elf_Sym *sym;
Elf_Rela *rela;
Elf_Rela r;
unsigned int r_sym;
const char *fromsec;
Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
Elf_Rela *stop = (void *)start + sechdr->sh_size;
fromsec = sech_name(elf, sechdr);
fromsec += strlen(".rela");
/* if from section (name) is know good then skip it */
if (match(fromsec, section_white_list))
return;
for (rela = start; rela < stop; rela++) {
r.r_offset = TO_NATIVE(rela->r_offset);
#if KERNEL_ELFCLASS == ELFCLASS64
if (elf->hdr->e_machine == EM_MIPS) {
unsigned int r_typ;
r_sym = ELF64_MIPS_R_SYM(rela->r_info);
r_sym = TO_NATIVE(r_sym);
r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
r.r_info = ELF64_R_INFO(r_sym, r_typ);
} else {
r.r_info = TO_NATIVE(rela->r_info);
r_sym = ELF_R_SYM(r.r_info);
}
#else
r.r_info = TO_NATIVE(rela->r_info);
r_sym = ELF_R_SYM(r.r_info);
#endif
r.r_addend = TO_NATIVE(rela->r_addend);
sym = elf->symtab_start + r_sym;
/* Skip special sections */
if (is_shndx_special(sym->st_shndx))
continue;
check_section_mismatch(modname, elf, &r, sym, fromsec);
}
}
static void section_rel(const char *modname, struct elf_info *elf,
Elf_Shdr *sechdr)
{
Elf_Sym *sym;
Elf_Rel *rel;
Elf_Rela r;
unsigned int r_sym;
const char *fromsec;
Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
Elf_Rel *stop = (void *)start + sechdr->sh_size;
fromsec = sech_name(elf, sechdr);
fromsec += strlen(".rel");
/* if from section (name) is know good then skip it */
if (match(fromsec, section_white_list))
return;
for (rel = start; rel < stop; rel++) {
r.r_offset = TO_NATIVE(rel->r_offset);
#if KERNEL_ELFCLASS == ELFCLASS64
if (elf->hdr->e_machine == EM_MIPS) {
unsigned int r_typ;
r_sym = ELF64_MIPS_R_SYM(rel->r_info);
r_sym = TO_NATIVE(r_sym);
r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
r.r_info = ELF64_R_INFO(r_sym, r_typ);
} else {
r.r_info = TO_NATIVE(rel->r_info);
r_sym = ELF_R_SYM(r.r_info);
}
#else
r.r_info = TO_NATIVE(rel->r_info);
r_sym = ELF_R_SYM(r.r_info);
#endif
r.r_addend = 0;
switch (elf->hdr->e_machine) {
case EM_386:
if (addend_386_rel(elf, sechdr, &r))
continue;
break;
case EM_ARM:
if (addend_arm_rel(elf, sechdr, &r))
continue;
break;
case EM_MIPS:
if (addend_mips_rel(elf, sechdr, &r))
continue;
break;
}
sym = elf->symtab_start + r_sym;
/* Skip special sections */
if (is_shndx_special(sym->st_shndx))
continue;
check_section_mismatch(modname, elf, &r, sym, fromsec);
}
}
/**
* A module includes a number of sections that are discarded
* either when loaded or when used as built-in.
* For loaded modules all functions marked __init and all data
* marked __initdata will be discarded when the module has been initialized.
* Likewise for modules used built-in the sections marked __exit
* are discarded because __exit marked function are supposed to be called
* only when a module is unloaded which never happens for built-in modules.
* The check_sec_ref() function traverses all relocation records
* to find all references to a section that reference a section that will
* be discarded and warns about it.
**/
static void check_sec_ref(struct module *mod, const char *modname,
struct elf_info *elf)
{
int i;
Elf_Shdr *sechdrs = elf->sechdrs;
/* Walk through all sections */
for (i = 0; i < elf->num_sections; i++) {
check_section(modname, elf, &elf->sechdrs[i]);
/* We want to process only relocation sections and not .init */
if (sechdrs[i].sh_type == SHT_RELA)
section_rela(modname, elf, &elf->sechdrs[i]);
else if (sechdrs[i].sh_type == SHT_REL)
section_rel(modname, elf, &elf->sechdrs[i]);
}
}
static void read_symbols(char *modname)
{
const char *symname;
char *version;
char *license;
struct module *mod;
struct elf_info info = { };
Elf_Sym *sym;
if (!parse_elf(&info, modname))
return;
mod = new_module(modname);
/* When there's no vmlinux, don't print warnings about
* unresolved symbols (since there'll be too many ;) */
if (is_vmlinux(modname)) {
have_vmlinux = 1;
mod->skip = 1;
}
license = get_modinfo(info.modinfo, info.modinfo_len, "license");
if (info.modinfo && !license && !is_vmlinux(modname))
warn("modpost: missing MODULE_LICENSE() in %s\n"
"see include/linux/module.h for "
"more information\n", modname);
while (license) {
if (license_is_gpl_compatible(license))
mod->gpl_compatible = 1;
else {
mod->gpl_compatible = 0;
break;
}
license = get_next_modinfo(info.modinfo, info.modinfo_len,
"license", license);
}
for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
symname = info.strtab + sym->st_name;
handle_modversions(mod, &info, sym, symname);
handle_moddevtable(mod, &info, sym, symname);
}
if (!is_vmlinux(modname) ||
(is_vmlinux(modname) && vmlinux_section_warnings))
check_sec_ref(mod, modname, &info);
version = get_modinfo(info.modinfo, info.modinfo_len, "version");
if (version)
maybe_frob_rcs_version(modname, version, info.modinfo,
version - (char *)info.hdr);
if (version || (all_versions && !is_vmlinux(modname)))
get_src_version(modname, mod->srcversion,
sizeof(mod->srcversion)-1);
parse_elf_finish(&info);
/* Our trick to get versioning for module struct etc. - it's
* never passed as an argument to an exported function, so
* the automatic versioning doesn't pick it up, but it's really
* important anyhow */
if (modversions)
mod->unres = alloc_symbol("module_layout", 0, mod->unres);
}
#define SZ 500
/* We first write the generated file into memory using the
* following helper, then compare to the file on disk and
* only update the later if anything changed */
void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
const char *fmt, ...)
{
char tmp[SZ];
int len;
va_list ap;
va_start(ap, fmt);
len = vsnprintf(tmp, SZ, fmt, ap);
buf_write(buf, tmp, len);
va_end(ap);
}
void buf_write(struct buffer *buf, const char *s, int len)
{
if (buf->size - buf->pos < len) {
buf->size += len + SZ;
buf->p = realloc(buf->p, buf->size);
}
strncpy(buf->p + buf->pos, s, len);
buf->pos += len;
}
static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
{
const char *e = is_vmlinux(m) ?"":".ko";
switch (exp) {
case export_gpl:
fatal("modpost: GPL-incompatible module %s%s "
"uses GPL-only symbol '%s'\n", m, e, s);
break;
case export_unused_gpl:
fatal("modpost: GPL-incompatible module %s%s "
"uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
break;
case export_gpl_future:
warn("modpost: GPL-incompatible module %s%s "
"uses future GPL-only symbol '%s'\n", m, e, s);
break;
case export_plain:
case export_unused:
case export_unknown:
/* ignore */
break;
}
}
static void check_for_unused(enum export exp, const char *m, const char *s)
{
const char *e = is_vmlinux(m) ?"":".ko";
switch (exp) {
case export_unused:
case export_unused_gpl:
warn("modpost: module %s%s "
"uses symbol '%s' marked UNUSED\n", m, e, s);
break;
default:
/* ignore */
break;
}
}
static void check_exports(struct module *mod)
{
struct symbol *s, *exp;
for (s = mod->unres; s; s = s->next) {
const char *basename;
exp = find_symbol(s->name);
if (!exp || exp->module == mod)
continue;
basename = strrchr(mod->name, '/');
if (basename)
basename++;
else
basename = mod->name;
if (!mod->gpl_compatible)
check_for_gpl_usage(exp->export, basename, exp->name);
check_for_unused(exp->export, basename, exp->name);
}
}
/**
* Header for the generated file
**/
static void add_header(struct buffer *b, struct module *mod)
{
buf_printf(b, "#include <linux/module.h>\n");
buf_printf(b, "#include <linux/vermagic.h>\n");
buf_printf(b, "#include <linux/compiler.h>\n");
buf_printf(b, "\n");
buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
buf_printf(b, "\n");
buf_printf(b, "struct module __this_module\n");
buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
buf_printf(b, " .name = KBUILD_MODNAME,\n");
if (mod->has_init)
buf_printf(b, " .init = init_module,\n");
if (mod->has_cleanup)
buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
" .exit = cleanup_module,\n"
"#endif\n");
buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
buf_printf(b, "};\n");
}
static void add_staging_flag(struct buffer *b, const char *name)
{
static const char *staging_dir = "drivers/staging";
if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
}
/**
* Record CRCs for unresolved symbols
**/
static int add_versions(struct buffer *b, struct module *mod)
{
struct symbol *s, *exp;
int err = 0;
for (s = mod->unres; s; s = s->next) {
exp = find_symbol(s->name);
if (!exp || exp->module == mod) {
if (have_vmlinux && !s->weak) {
if (warn_unresolved) {
warn("\"%s\" [%s.ko] undefined!\n",
s->name, mod->name);
} else {
merror("\"%s\" [%s.ko] undefined!\n",
s->name, mod->name);
err = 1;
}
}
continue;
}
s->module = exp->module;
s->crc_valid = exp->crc_valid;
s->crc = exp->crc;
}
if (!modversions)
return err;
buf_printf(b, "\n");
buf_printf(b, "static const struct modversion_info ____versions[]\n");
buf_printf(b, "__used\n");
buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
for (s = mod->unres; s; s = s->next) {
if (!s->module)
continue;
if (!s->crc_valid) {
warn("\"%s\" [%s.ko] has no CRC!\n",
s->name, mod->name);
continue;
}
buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
}
buf_printf(b, "};\n");
return err;
}
static void add_depends(struct buffer *b, struct module *mod,
struct module *modules)
{
struct symbol *s;
struct module *m;
int first = 1;
for (m = modules; m; m = m->next)
m->seen = is_vmlinux(m->name);
buf_printf(b, "\n");
buf_printf(b, "static const char __module_depends[]\n");
buf_printf(b, "__used\n");
buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
buf_printf(b, "\"depends=");
for (s = mod->unres; s; s = s->next) {
const char *p;
if (!s->module)
continue;
if (s->module->seen)
continue;
s->module->seen = 1;
p = strrchr(s->module->name, '/');
if (p)
p++;
else
p = s->module->name;
buf_printf(b, "%s%s", first ? "" : ",", p);
first = 0;
}
buf_printf(b, "\";\n");
}
static void add_srcversion(struct buffer *b, struct module *mod)
{
if (mod->srcversion[0]) {
buf_printf(b, "\n");
buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
mod->srcversion);
}
}
static void write_if_changed(struct buffer *b, const char *fname)
{
char *tmp;
FILE *file;
struct stat st;
file = fopen(fname, "r");
if (!file)
goto write;
if (fstat(fileno(file), &st) < 0)
goto close_write;
if (st.st_size != b->pos)
goto close_write;
tmp = NOFAIL(malloc(b->pos));
if (fread(tmp, 1, b->pos, file) != b->pos)
goto free_write;
if (memcmp(tmp, b->p, b->pos) != 0)
goto free_write;
free(tmp);
fclose(file);
return;
free_write:
free(tmp);
close_write:
fclose(file);
write:
file = fopen(fname, "w");
if (!file) {
perror(fname);
exit(1);
}
if (fwrite(b->p, 1, b->pos, file) != b->pos) {
perror(fname);
exit(1);
}
fclose(file);
}
/* parse Module.symvers file. line format:
* 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
**/
static void read_dump(const char *fname, unsigned int kernel)
{
unsigned long size, pos = 0;
void *file = grab_file(fname, &size);
char *line;
if (!file)
/* No symbol versions, silently ignore */
return;
while ((line = get_next_line(&pos, file, size))) {
char *symname, *modname, *d, *export, *end;
unsigned int crc;
struct module *mod;
struct symbol *s;
if (!(symname = strchr(line, '\t')))
goto fail;
*symname++ = '\0';
if (!(modname = strchr(symname, '\t')))
goto fail;
*modname++ = '\0';
if ((export = strchr(modname, '\t')) != NULL)
*export++ = '\0';
if (export && ((end = strchr(export, '\t')) != NULL))
*end = '\0';
crc = strtoul(line, &d, 16);
if (*symname == '\0' || *modname == '\0' || *d != '\0')
goto fail;
mod = find_module(modname);
if (!mod) {
if (is_vmlinux(modname))
have_vmlinux = 1;
mod = new_module(modname);
mod->skip = 1;
}
s = sym_add_exported(symname, mod, export_no(export));
s->kernel = kernel;
s->preloaded = 1;
sym_update_crc(symname, mod, crc, export_no(export));
}
return;
fail:
fatal("parse error in symbol dump file\n");
}
/* For normal builds always dump all symbols.
* For external modules only dump symbols
* that are not read from kernel Module.symvers.
**/
static int dump_sym(struct symbol *sym)
{
if (!external_module)
return 1;
if (sym->vmlinux || sym->kernel)
return 0;
return 1;
}
static void write_dump(const char *fname)
{
struct buffer buf = { };
struct symbol *symbol;
int n;
for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
symbol = symbolhash[n];
while (symbol) {
if (dump_sym(symbol))
buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
symbol->crc, symbol->name,
symbol->module->name,
export_str(symbol->export));
symbol = symbol->next;
}
}
write_if_changed(&buf, fname);
}
struct ext_sym_list {
struct ext_sym_list *next;
const char *file;
};
int main(int argc, char **argv)
{
struct module *mod;
struct buffer buf = { };
char *kernel_read = NULL, *module_read = NULL;
char *dump_write = NULL;
int opt;
int err;
struct ext_sym_list *extsym_iter;
struct ext_sym_list *extsym_start = NULL;
while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:")) != -1) {
switch (opt) {
case 'i':
kernel_read = optarg;
break;
case 'I':
module_read = optarg;
external_module = 1;
break;
case 'c':
cross_build = 1;
break;
case 'e':
external_module = 1;
extsym_iter =
NOFAIL(malloc(sizeof(*extsym_iter)));
extsym_iter->next = extsym_start;
extsym_iter->file = optarg;
extsym_start = extsym_iter;
break;
case 'm':
modversions = 1;
break;
case 'o':
dump_write = optarg;
break;
case 'a':
all_versions = 1;
break;
case 's':
vmlinux_section_warnings = 0;
break;
case 'S':
sec_mismatch_verbose = 0;
break;
case 'w':
warn_unresolved = 1;
break;
default:
exit(1);
}
}
if (kernel_read)
read_dump(kernel_read, 1);
if (module_read)
read_dump(module_read, 0);
while (extsym_start) {
read_dump(extsym_start->file, 0);
extsym_iter = extsym_start->next;
free(extsym_start);
extsym_start = extsym_iter;
}
while (optind < argc)
read_symbols(argv[optind++]);
for (mod = modules; mod; mod = mod->next) {
if (mod->skip)
continue;
check_exports(mod);
}
err = 0;
for (mod = modules; mod; mod = mod->next) {
char fname[strlen(mod->name) + 10];
if (mod->skip)
continue;
buf.pos = 0;
add_header(&buf, mod);
add_staging_flag(&buf, mod->name);
err |= add_versions(&buf, mod);
add_depends(&buf, mod, modules);
add_moddevtable(&buf, mod);
add_srcversion(&buf, mod);
sprintf(fname, "%s.mod.c", mod->name);
write_if_changed(&buf, fname);
}
if (dump_write)
write_dump(dump_write);
if (sec_mismatch_count && !sec_mismatch_verbose)
warn("modpost: Found %d section mismatch(es).\n"
"To see full details build your kernel with:\n"
"'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
sec_mismatch_count);
return err;
}
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