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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/scripts/mod/modpost.c

1632 строки
40 KiB
C
Исходник Ответственный История

/* Postprocess module symbol versions
*
* Copyright 2003 Kai Germaschewski
* Copyright 2002-2004 Rusty Russell, IBM Corporation
* Copyright 2006 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 ...
*/
#include <ctype.h>
#include "modpost.h"
#include "../../include/linux/license.h"
/* 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;
/* Only warn about unresolved symbols */
static int warn_unresolved = 0;
/* How a symbol is exported */
enum export {
export_plain, export_unused, export_gpl,
export_unused_gpl, export_gpl_future, export_unknown
};
void fatal(const char *fmt, ...)
{
va_list arglist;
fprintf(stderr, "FATAL: ");
va_start(arglist, fmt);
vfprintf(stderr, fmt, arglist);
va_end(arglist);
exit(1);
}
void warn(const char *fmt, ...)
{
va_list arglist;
fprintf(stderr, "WARNING: ");
va_start(arglist, fmt);
vfprintf(stderr, fmt, arglist);
va_end(arglist);
}
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;
if ((myname = strrchr(modname, '/')))
myname++;
else
myname = modname;
return strcmp(myname, "vmlinux") == 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 */
if ((s = strrchr(p, '.')) != 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, Elf_Section 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");
}
}
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;
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_shoff = TO_NATIVE(hdr->e_shoff);
hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
hdr->e_machine = TO_NATIVE(hdr->e_machine);
sechdrs = (void *)hdr + hdr->e_shoff;
info->sechdrs = sechdrs;
/* Fix endianness in section headers */
for (i = 0; i < hdr->e_shnum; i++) {
sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
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_name = TO_NATIVE(sechdrs[i].sh_name);
}
/* Find symbol table. */
for (i = 1; i < hdr->e_shnum; i++) {
const char *secstrings
= (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
const char *secname;
if (sechdrs[i].sh_offset > info->size) {
fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename, (unsigned int)sechdrs[i].sh_offset, sizeof(*hdr));
return 0;
}
secname = secstrings + sechdrs[i].sh_name;
if (strcmp(secname, ".modinfo") == 0) {
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)
continue;
info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset
+ sechdrs[i].sh_size;
info->strtab = (void *)hdr +
sechdrs[sechdrs[i].sh_link].sh_offset;
}
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);
}
return 1;
}
static void parse_elf_finish(struct elf_info *info)
{
release_file(info->hdr, info->size);
}
#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, sym->st_shndx);
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 (memcmp(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;
/* ignore global offset table */
if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
break;
/* ignore __this_module, it will be resolved shortly */
if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
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 (memcmp(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);
}
/**
* Whitelist to allow certain references to pass with no warning.
*
* Pattern 0:
* Do not warn if funtion/data are marked with __init_refok/__initdata_refok.
* The pattern is identified by:
* fromsec = .text.init.refok | .data.init.refok
*
* 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 2:
* Many drivers utilise a *driver container with references to
* add, remove, probe functions etc.
* These functions may often be marked __init and we do not want to
* warn here.
* the pattern is identified by:
* tosec = .init.text | .exit.text | .init.data
* fromsec = .data
* atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console
*
* Pattern 3:
* Whitelist all references from .pci_fixup* section to .init.text
* This is part of the PCI init when built-in
*
* Pattern 4:
* Whitelist all refereces from .text.head to .init.data
* Whitelist all refereces from .text.head to .init.text
*
* Pattern 5:
* 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
*
* Pattern 7:
* Logos used in drivers/video/logo reside in __initdata but the
* funtion that references them are EXPORT_SYMBOL() so cannot be
* marker __init. So we whitelist them here.
* The pattern is:
* tosec = .init.data
* fromsec = .text*
* refsymname = logo_
*
* Pattern 8:
* Symbols contained in .paravirtprobe may safely reference .init.text.
* The pattern is:
* tosec = .init.text
* fromsec = .paravirtprobe
*
* Pattern 10:
* ia64 has machvec table for each platform and
* powerpc has a machine desc table for each platform.
* It is mixture of function pointers of .init.text and .text.
* fromsec = .machvec | .machine.desc
**/
static int secref_whitelist(const char *modname, const char *tosec,
const char *fromsec, const char *atsym,
const char *refsymname)
{
int f1 = 1, f2 = 1;
const char **s;
const char *pat2sym[] = {
"driver",
"_template", /* scsi uses *_template a lot */
"_sht", /* scsi also used *_sht to some extent */
"_ops",
"_probe",
"_probe_one",
"_console",
"apic_es7000",
NULL
};
const char *pat3refsym[] = {
"__init_begin",
"_sinittext",
"_einittext",
NULL
};
/* Check for pattern 0 */
if ((strcmp(fromsec, ".text.init.refok") == 0) ||
(strcmp(fromsec, ".data.init.refok") == 0))
return 1;
/* Check for pattern 1 */
if (strcmp(tosec, ".init.data") != 0)
f1 = 0;
if (strncmp(fromsec, ".data", strlen(".data")) != 0)
f1 = 0;
if (strncmp(atsym, "__param", strlen("__param")) != 0)
f1 = 0;
if (f1)
return f1;
/* Check for pattern 2 */
if ((strcmp(tosec, ".init.text") != 0) &&
(strcmp(tosec, ".exit.text") != 0) &&
(strcmp(tosec, ".init.data") != 0))
f2 = 0;
if (strcmp(fromsec, ".data") != 0)
f2 = 0;
for (s = pat2sym; *s; s++)
if (strrcmp(atsym, *s) == 0)
f1 = 1;
if (f1 && f2)
return 1;
/* Check for pattern 3 */
if ((strncmp(fromsec, ".pci_fixup", strlen(".pci_fixup")) == 0) &&
(strcmp(tosec, ".init.text") == 0))
return 1;
/* Check for pattern 4 */
if ((strcmp(fromsec, ".text.head") == 0) &&
((strcmp(tosec, ".init.data") == 0) ||
(strcmp(tosec, ".init.text") == 0)))
return 1;
/* Check for pattern 5 */
for (s = pat3refsym; *s; s++)
if (strcmp(refsymname, *s) == 0)
return 1;
/* Check for pattern 7 */
if ((strcmp(tosec, ".init.data") == 0) &&
(strncmp(fromsec, ".text", strlen(".text")) == 0) &&
(strncmp(refsymname, "logo_", strlen("logo_")) == 0))
return 1;
/* Check for pattern 8 */
if ((strcmp(tosec, ".init.text") == 0) &&
(strcmp(fromsec, ".paravirtprobe") == 0))
return 1;
/* Check for pattern 10 */
if ((strcmp(fromsec, ".machvec") == 0) ||
(strcmp(fromsec, ".machine.desc") == 0))
return 1;
return 0;
}
/**
* 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, Elf_Addr addr,
Elf_Sym *relsym)
{
Elf_Sym *sym;
if (relsym->st_name != 0)
return relsym;
for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
if (sym->st_shndx != relsym->st_shndx)
continue;
if (sym->st_value == addr)
return sym;
}
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 void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
const char *sec,
Elf_Sym **before, Elf_Sym **after)
{
Elf_Sym *sym;
Elf_Ehdr *hdr = elf->hdr;
Elf_Addr beforediff = ~0;
Elf_Addr afterdiff = ~0;
const char *secstrings = (void *)hdr +
elf->sechdrs[hdr->e_shstrndx].sh_offset;
*before = NULL;
*after = NULL;
for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
const char *symsec;
if (sym->st_shndx >= SHN_LORESERVE)
continue;
symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
if (strcmp(symsec, sec) != 0)
continue;
if (!is_valid_name(elf, sym))
continue;
if (sym->st_value <= addr) {
if ((addr - sym->st_value) < beforediff) {
beforediff = addr - sym->st_value;
*before = sym;
}
else if ((addr - sym->st_value) == beforediff) {
*before = sym;
}
}
else
{
if ((sym->st_value - addr) < afterdiff) {
afterdiff = sym->st_value - addr;
*after = sym;
}
else if ((sym->st_value - addr) == afterdiff) {
*after = sym;
}
}
}
}
/**
* 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 warn_sec_mismatch(const char *modname, const char *fromsec,
struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
{
const char *refsymname = "";
Elf_Sym *before, *after;
Elf_Sym *refsym;
Elf_Ehdr *hdr = elf->hdr;
Elf_Shdr *sechdrs = elf->sechdrs;
const char *secstrings = (void *)hdr +
sechdrs[hdr->e_shstrndx].sh_offset;
const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
refsym = find_elf_symbol(elf, r.r_addend, sym);
if (refsym && strlen(elf->strtab + refsym->st_name))
refsymname = elf->strtab + refsym->st_name;
/* check whitelist - we may ignore it */
if (before &&
secref_whitelist(modname, secname, fromsec,
elf->strtab + before->st_name, refsymname))
return;
/* fromsec whitelist - without a valid 'before'
* powerpc has a GOT table in .got2 section */
if (strcmp(fromsec, ".got2") == 0)
return;
if (before && after) {
warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
"(between '%s' and '%s')\n",
modname, fromsec, (unsigned long long)r.r_offset,
secname, refsymname,
elf->strtab + before->st_name,
elf->strtab + after->st_name);
} else if (before) {
warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
"(after '%s')\n",
modname, fromsec, (unsigned long long)r.r_offset,
secname, refsymname,
elf->strtab + before->st_name);
} else if (after) {
warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
"before '%s' (at offset -0x%llx)\n",
modname, fromsec, (unsigned long long)r.r_offset,
secname, refsymname,
elf->strtab + after->st_name);
} else {
warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n",
modname, fromsec, (unsigned long long)r.r_offset,
secname, refsymname);
}
}
/**
* 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 intialized.
* Likewise for modules used built-in the sections marked __exit
* are discarded because __exit marked function are supposed to be called
* only when a moduel is unloaded which never happes 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 section(const char*),
int section_ref_ok(const char *))
{
int i;
Elf_Sym *sym;
Elf_Ehdr *hdr = elf->hdr;
Elf_Shdr *sechdrs = elf->sechdrs;
const char *secstrings = (void *)hdr +
sechdrs[hdr->e_shstrndx].sh_offset;
/* Walk through all sections */
for (i = 0; i < hdr->e_shnum; i++) {
const char *name = secstrings + sechdrs[i].sh_name;
const char *secname;
Elf_Rela r;
unsigned int r_sym;
/* We want to process only relocation sections and not .init */
if (sechdrs[i].sh_type == SHT_RELA) {
Elf_Rela *rela;
Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
Elf_Rela *stop = (void*)start + sechdrs[i].sh_size;
name += strlen(".rela");
if (section_ref_ok(name))
continue;
for (rela = start; rela < stop; rela++) {
r.r_offset = TO_NATIVE(rela->r_offset);
#if KERNEL_ELFCLASS == ELFCLASS64
if (hdr->e_machine == EM_MIPS) {
r_sym = ELF64_MIPS_R_SYM(rela->r_info);
r_sym = TO_NATIVE(r_sym);
} 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 (sym->st_shndx >= SHN_LORESERVE)
continue;
secname = secstrings +
sechdrs[sym->st_shndx].sh_name;
if (section(secname))
warn_sec_mismatch(modname, name,
elf, sym, r);
}
} else if (sechdrs[i].sh_type == SHT_REL) {
Elf_Rel *rel;
Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
Elf_Rel *stop = (void*)start + sechdrs[i].sh_size;
name += strlen(".rel");
if (section_ref_ok(name))
continue;
for (rel = start; rel < stop; rel++) {
r.r_offset = TO_NATIVE(rel->r_offset);
#if KERNEL_ELFCLASS == ELFCLASS64
if (hdr->e_machine == EM_MIPS) {
r_sym = ELF64_MIPS_R_SYM(rel->r_info);
r_sym = TO_NATIVE(r_sym);
} 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;
sym = elf->symtab_start + r_sym;
/* Skip special sections */
if (sym->st_shndx >= SHN_LORESERVE)
continue;
secname = secstrings +
sechdrs[sym->st_shndx].sh_name;
if (section(secname))
warn_sec_mismatch(modname, name,
elf, sym, r);
}
}
}
}
/**
* Functions used only during module init is marked __init and is stored in
* a .init.text section. Likewise data is marked __initdata and stored in
* a .init.data section.
* If this section is one of these sections return 1
* See include/linux/init.h for the details
**/
static int init_section(const char *name)
{
if (strcmp(name, ".init") == 0)
return 1;
if (strncmp(name, ".init.", strlen(".init.")) == 0)
return 1;
return 0;
}
/**
* Identify sections from which references to a .init section is OK.
*
* Unfortunately references to read only data that referenced .init
* sections had to be excluded. Almost all of these are false
* positives, they are created by gcc. The downside of excluding rodata
* is that there really are some user references from rodata to
* init code, e.g. drivers/video/vgacon.c:
*
* const struct consw vga_con = {
* con_startup: vgacon_startup,
*
* where vgacon_startup is __init. If you want to wade through the false
* positives, take out the check for rodata.
**/
static int init_section_ref_ok(const char *name)
{
const char **s;
/* Absolute section names */
const char *namelist1[] = {
".init",
".opd", /* see comment [OPD] at exit_section_ref_ok() */
".toc1", /* used by ppc64 */
".stab",
".data.rel.ro", /* used by parisc64 */
".parainstructions",
".text.lock",
"__bug_table", /* used by powerpc for BUG() */
".pci_fixup_header",
".pci_fixup_final",
".pdr",
"__param",
"__ex_table",
".fixup",
".smp_locks",
".plt", /* seen on ARCH=um build on x86_64. Harmless */
"__ftr_fixup", /* powerpc cpu feature fixup */
"__fw_ftr_fixup", /* powerpc firmware feature fixup */
NULL
};
/* Start of section names */
const char *namelist2[] = {
".init.",
".altinstructions",
".eh_frame",
".debug",
".parainstructions",
".rodata",
NULL
};
/* part of section name */
const char *namelist3 [] = {
".unwind", /* sample: IA_64.unwind.init.text */
NULL
};
for (s = namelist1; *s; s++)
if (strcmp(*s, name) == 0)
return 1;
for (s = namelist2; *s; s++)
if (strncmp(*s, name, strlen(*s)) == 0)
return 1;
for (s = namelist3; *s; s++)
if (strstr(name, *s) != NULL)
return 1;
if (strrcmp(name, ".init") == 0)
return 1;
return 0;
}
/*
* Functions used only during module exit is marked __exit and is stored in
* a .exit.text section. Likewise data is marked __exitdata and stored in
* a .exit.data section.
* If this section is one of these sections return 1
* See include/linux/init.h for the details
**/
static int exit_section(const char *name)
{
if (strcmp(name, ".exit.text") == 0)
return 1;
if (strcmp(name, ".exit.data") == 0)
return 1;
return 0;
}
/*
* Identify sections from which references to a .exit section is OK.
*
* [OPD] Keith Ownes <kaos@sgi.com> commented:
* For our future {in}sanity, add a comment that this is the ppc .opd
* section, not the ia64 .opd section.
* ia64 .opd should not point to discarded sections.
* [.rodata] like for .init.text we ignore .rodata references -same reason
**/
static int exit_section_ref_ok(const char *name)
{
const char **s;
/* Absolute section names */
const char *namelist1[] = {
".exit.text",
".exit.data",
".init.text",
".rodata",
".opd", /* See comment [OPD] */
".toc1", /* used by ppc64 */
".altinstructions",
".pdr",
"__bug_table", /* used by powerpc for BUG() */
".exitcall.exit",
".eh_frame",
".parainstructions",
".stab",
"__ex_table",
".fixup",
".smp_locks",
".plt", /* seen on ARCH=um build on x86_64. Harmless */
NULL
};
/* Start of section names */
const char *namelist2[] = {
".debug",
NULL
};
/* part of section name */
const char *namelist3 [] = {
".unwind", /* Sample: IA_64.unwind.exit.text */
NULL
};
for (s = namelist1; *s; s++)
if (strcmp(*s, name) == 0)
return 1;
for (s = namelist2; *s; s++)
if (strncmp(*s, name, strlen(*s)) == 0)
return 1;
for (s = namelist3; *s; s++)
if (strstr(name, *s) != NULL)
return 1;
return 0;
}
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");
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);
}
check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
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 struct_module - 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("struct_module", 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");
}
/**
* 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, "__attribute_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, "__attribute_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;
if ((p = strrchr(s->module->name, '/')) != NULL)
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;
if (!(mod = find_module(modname))) {
if (is_vmlinux(modname)) {
have_vmlinux = 1;
}
mod = new_module(NOFAIL(strdup(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);
}
int main(int argc, char **argv)
{
struct module *mod;
struct buffer buf = { };
char fname[SZ];
char *kernel_read = NULL, *module_read = NULL;
char *dump_write = NULL;
int opt;
int err;
while ((opt = getopt(argc, argv, "i:I:mo:aw")) != -1) {
switch(opt) {
case 'i':
kernel_read = optarg;
break;
case 'I':
module_read = optarg;
external_module = 1;
break;
case 'm':
modversions = 1;
break;
case 'o':
dump_write = optarg;
break;
case 'a':
all_versions = 1;
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 (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) {
if (mod->skip)
continue;
buf.pos = 0;
add_header(&buf, mod);
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);
return err;
}
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