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linux/scripts/mod/modpost.c
Masahiro Yamada 1c4a7587d1 modpost: fix section mismatch message for RELA 
The section mismatch check prints a bogus symbol name on some
architectures.

[test code]

  #include <linux/init.h>

  int __initdata foo;
  int get_foo(void) { return foo; }

If you compile it with GCC for riscv or loongarch, modpost will show an
incorrect symbol name:

  WARNING: modpost: vmlinux: section mismatch in reference: get_foo+0x8 (section: .text) -> done (section: .init.data)

To get the correct symbol address, the st_value must be added.

This issue has never been noticed since commit 93684d3b80 ("kbuild:
include symbol names in section mismatch warnings") presumably because
st_value becomes zero on most architectures when the referenced symbol
is looked up. It is not true for riscv or loongarch, at least.

With this fix, modpost will show the correct symbol name:

  WARNING: modpost: vmlinux: section mismatch in reference: get_foo+0x8 (section: .text) -> foo (section: .init.data)

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2023-11-16 20:14:44 +09:00

2288 lines
57 KiB
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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 <elf.h>
#include <fnmatch.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <limits.h>
#include <stdbool.h>
#include <errno.h>
#include "modpost.h"
#include "../../include/linux/license.h"
static bool module_enabled;
/* Are we using CONFIG_MODVERSIONS? */
static bool modversions;
/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
static bool all_versions;
/* If we are modposting external module set to 1 */
static bool external_module;
/* Only warn about unresolved symbols */
static bool warn_unresolved;
static int sec_mismatch_count;
static bool sec_mismatch_warn_only = true;
/* Trim EXPORT_SYMBOLs that are unused by in-tree modules */
static bool trim_unused_exports;
/* ignore missing files */
static bool ignore_missing_files;
/* If set to 1, only warn (instead of error) about missing ns imports */
static bool allow_missing_ns_imports;
static bool error_occurred;
static bool extra_warn;
/*
* Cut off the warnings when there are too many. This typically occurs when
* vmlinux is missing. ('make modules' without building vmlinux.)
*/
#define MAX_UNRESOLVED_REPORTS 10
static unsigned int nr_unresolved;
/* In kernel, this size is defined in linux/module.h;
* here we use Elf_Addr instead of long for covering cross-compile
*/
#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
void __attribute__((format(printf, 2, 3)))
modpost_log(enum loglevel loglevel, const char *fmt, ...)
{
va_list arglist;
switch (loglevel) {
case LOG_WARN:
fprintf(stderr, "WARNING: ");
break;
case LOG_ERROR:
fprintf(stderr, "ERROR: ");
break;
case LOG_FATAL:
fprintf(stderr, "FATAL: ");
break;
default: /* invalid loglevel, ignore */
break;
}
fprintf(stderr, "modpost: ");
va_start(arglist, fmt);
vfprintf(stderr, fmt, arglist);
va_end(arglist);
if (loglevel == LOG_FATAL)
exit(1);
if (loglevel == LOG_ERROR)
error_occurred = true;
}
static inline bool strends(const char *str, const char *postfix)
{
if (strlen(str) < strlen(postfix))
return false;
return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
}
void *do_nofail(void *ptr, const char *expr)
{
if (!ptr)
fatal("Memory allocation failure: %s.\n", expr);
return ptr;
}
char *read_text_file(const char *filename)
{
struct stat st;
size_t nbytes;
int fd;
char *buf;
fd = open(filename, O_RDONLY);
if (fd < 0) {
perror(filename);
exit(1);
}
if (fstat(fd, &st) < 0) {
perror(filename);
exit(1);
}
buf = NOFAIL(malloc(st.st_size + 1));
nbytes = st.st_size;
while (nbytes) {
ssize_t bytes_read;
bytes_read = read(fd, buf, nbytes);
if (bytes_read < 0) {
perror(filename);
exit(1);
}
nbytes -= bytes_read;
}
buf[st.st_size] = '\0';
close(fd);
return buf;
}
char *get_line(char **stringp)
{
char *orig = *stringp, *next;
/* do not return the unwanted extra line at EOF */
if (!orig || *orig == '\0')
return NULL;
/* don't use strsep here, it is not available everywhere */
next = strchr(orig, '\n');
if (next)
*next++ = '\0';
*stringp = next;
return orig;
}
/* A list of all modules we processed */
LIST_HEAD(modules);
static struct module *find_module(const char *modname)
{
struct module *mod;
list_for_each_entry(mod, &modules, list) {
if (strcmp(mod->name, modname) == 0)
return mod;
}
return NULL;
}
static struct module *new_module(const char *name, size_t namelen)
{
struct module *mod;
mod = NOFAIL(malloc(sizeof(*mod) + namelen + 1));
memset(mod, 0, sizeof(*mod));
INIT_LIST_HEAD(&mod->exported_symbols);
INIT_LIST_HEAD(&mod->unresolved_symbols);
INIT_LIST_HEAD(&mod->missing_namespaces);
INIT_LIST_HEAD(&mod->imported_namespaces);
memcpy(mod->name, name, namelen);
mod->name[namelen] = '\0';
mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0);
/*
* Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE()
* is missing, do not check the use for EXPORT_SYMBOL_GPL() becasue
* modpost will exit wiht error anyway.
*/
mod->is_gpl_compatible = true;
list_add_tail(&mod->list, &modules);
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 list_head list; /* link to module::exported_symbols or module::unresolved_symbols */
struct module *module;
char *namespace;
unsigned int crc;
bool crc_valid;
bool weak;
bool is_func;
bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */
bool used; /* there exists a user of this symbol */
char name[];
};
static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
/* This is based on the hash algorithm 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)
{
struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
memset(s, 0, sizeof(*s));
strcpy(s->name, name);
return s;
}
/* For the hash of exported symbols */
static void hash_add_symbol(struct symbol *sym)
{
unsigned int hash;
hash = tdb_hash(sym->name) % SYMBOL_HASH_SIZE;
sym->next = symbolhash[hash];
symbolhash[hash] = sym;
}
static void sym_add_unresolved(const char *name, struct module *mod, bool weak)
{
struct symbol *sym;
sym = alloc_symbol(name);
sym->weak = weak;
list_add_tail(&sym->list, &mod->unresolved_symbols);
}
static struct symbol *sym_find_with_module(const char *name, struct module *mod)
{
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 && (!mod || s->module == mod))
return s;
}
return NULL;
}
static struct symbol *find_symbol(const char *name)
{
return sym_find_with_module(name, NULL);
}
struct namespace_list {
struct list_head list;
char namespace[];
};
static bool contains_namespace(struct list_head *head, const char *namespace)
{
struct namespace_list *list;
/*
* The default namespace is null string "", which is always implicitly
* contained.
*/
if (!namespace[0])
return true;
list_for_each_entry(list, head, list) {
if (!strcmp(list->namespace, namespace))
return true;
}
return false;
}
static void add_namespace(struct list_head *head, const char *namespace)
{
struct namespace_list *ns_entry;
if (!contains_namespace(head, namespace)) {
ns_entry = NOFAIL(malloc(sizeof(*ns_entry) +
strlen(namespace) + 1));
strcpy(ns_entry->namespace, namespace);
list_add_tail(&ns_entry->list, head);
}
}
static void *sym_get_data_by_offset(const struct elf_info *info,
unsigned int secindex, unsigned long offset)
{
Elf_Shdr *sechdr = &info->sechdrs[secindex];
return (void *)info->hdr + sechdr->sh_offset + offset;
}
void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
{
return sym_get_data_by_offset(info, get_secindex(info, sym),
sym->st_value);
}
static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
{
return sym_get_data_by_offset(info, info->secindex_strings,
sechdr->sh_name);
}
static const char *sec_name(const struct elf_info *info, unsigned int secindex)
{
/*
* If sym->st_shndx is a special section index, there is no
* corresponding section header.
* Return "" if the index is out of range of info->sechdrs[] array.
*/
if (secindex >= info->num_sections)
return "";
return sech_name(info, &info->sechdrs[secindex]);
}
#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
static struct symbol *sym_add_exported(const char *name, struct module *mod,
bool gpl_only, const char *namespace)
{
struct symbol *s = find_symbol(name);
if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) {
error("%s: '%s' exported twice. Previous export was in %s%s\n",
mod->name, name, s->module->name,
s->module->is_vmlinux ? "" : ".ko");
}
s = alloc_symbol(name);
s->module = mod;
s->is_gpl_only = gpl_only;
s->namespace = NOFAIL(strdup(namespace));
list_add_tail(&s->list, &mod->exported_symbols);
hash_add_symbol(s);
return s;
}
static void sym_set_crc(struct symbol *sym, unsigned int crc)
{
sym->crc = crc;
sym->crc_valid = true;
}
static void *grab_file(const char *filename, size_t *size)
{
struct stat st;
void *map = MAP_FAILED;
int fd;
fd = open(filename, O_RDONLY);
if (fd < 0)
return NULL;
if (fstat(fd, &st))
goto failed;
*size = st.st_size;
map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
failed:
close(fd);
if (map == MAP_FAILED)
return NULL;
return map;
}
static void release_file(void *file, size_t 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) {
if (ignore_missing_files) {
fprintf(stderr, "%s: %s (ignored)\n", filename,
strerror(errno));
return 0;
}
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;
/* modpost only works for relocatable objects */
if (hdr->e_type != ET_REL)
fatal("%s: not relocatable object.", filename);
/* Check if file offset is correct */
if (hdr->e_shoff > info->size) {
fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\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, ".export_symbol")) {
info->export_symbol_secndx = 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);
}
symsearch_init(info);
return 1;
}
static void parse_elf_finish(struct elf_info *info)
{
symsearch_finish(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, "__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 (strstarts(symname, "_restgpr_") ||
strstarts(symname, "_savegpr_") ||
strstarts(symname, "_rest32gpr_") ||
strstarts(symname, "_save32gpr_") ||
strstarts(symname, "_restvr_") ||
strstarts(symname, "_savevr_"))
return 1;
if (info->hdr->e_machine == EM_PPC64)
/* Special register function linked on all modules during final link of .ko */
if (strstarts(symname, "_restgpr0_") ||
strstarts(symname, "_savegpr0_") ||
strstarts(symname, "_restvr_") ||
strstarts(symname, "_savevr_") ||
strcmp(symname, ".TOC.") == 0)
return 1;
if (info->hdr->e_machine == EM_S390)
/* Expoline thunks are linked on all kernel modules during final link of .ko */
if (strstarts(symname, "__s390_indirect_jump_r"))
return 1;
/* Do not ignore this symbol */
return 0;
}
static void handle_symbol(struct module *mod, struct elf_info *info,
const Elf_Sym *sym, const char *symname)
{
switch (sym->st_shndx) {
case SHN_COMMON:
if (strstarts(symname, "__gnu_lto_")) {
/* Should warn here, but modpost runs before the linker */
} else
warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
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;
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 = NOFAIL(strdup(symname));
munged[0] = '_';
munged[1] = toupper(munged[1]);
symname = munged;
}
}
sym_add_unresolved(symname, mod,
ELF_ST_BIND(sym->st_info) == STB_WEAK);
break;
default:
if (strcmp(symname, "init_module") == 0)
mod->has_init = true;
if (strcmp(symname, "cleanup_module") == 0)
mod->has_cleanup = true;
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(struct elf_info *info, const char *tag,
char *prev)
{
char *p;
unsigned int taglen = strlen(tag);
char *modinfo = info->modinfo;
unsigned long size = info->modinfo_len;
if (prev) {
size -= prev - modinfo;
modinfo = next_string(prev, &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(struct elf_info *info, const char *tag)
{
return get_next_modinfo(info, tag, NULL);
}
static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
{
if (sym)
return elf->strtab + sym->st_name;
else
return "(unknown)";
}
/*
* Check whether the 'string' argument matches one of the 'patterns',
* an array of shell wildcard patterns (glob).
*
* Return true is there is a match.
*/
static bool match(const char *string, const char *const patterns[])
{
const char *pattern;
while ((pattern = *patterns++)) {
if (!fnmatch(pattern, string, 0))
return true;
}
return false;
}
/* useful to pass patterns to match() directly */
#define PATTERNS(...) \
({ \
static const char *const patterns[] = {__VA_ARGS__, NULL}; \
patterns; \
})
/* sections that we do not want to do full section mismatch check on */
static const char *const section_white_list[] =
{
".comment*",
".debug*",
".zdebug*", /* Compressed debug sections. */
".GCC.command.line", /* record-gcc-switches */
".mdebug*", /* alpha, score, mips etc. */
".pdr", /* alpha, score, mips etc. */
".stab*",
".note*",
".got*",
".toc*",
".xt.prop", /* xtensa */
".xt.lit", /* xtensa */
".arcextmap*", /* arc */
".gnu.linkonce.arcext*", /* arc : modules */
".cmem*", /* EZchip */
".fmt_slot*", /* EZchip */
".gnu.lto*",
".discard.*",
".llvm.call-graph-profile", /* call graph */
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", ".meminit.rodata", \
".init.data", ".meminit.data"
#define ALL_PCI_INIT_SECTIONS \
".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
".pci_fixup_enable", ".pci_fixup_resume", \
".pci_fixup_resume_early", ".pci_fixup_suspend"
#define ALL_XXXINIT_SECTIONS ".meminit.*"
#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
#define ALL_EXIT_SECTIONS ".exit.*"
#define DATA_SECTIONS ".data", ".data.rel"
#define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \
".kprobes.text", ".cpuidle.text", ".noinstr.text"
#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
".fixup", ".entry.text", ".exception.text", \
".coldtext", ".softirqentry.text"
#define INIT_SECTIONS ".init.*"
#define ALL_TEXT_SECTIONS ".init.text", ".meminit.text", ".exit.text", \
TEXT_SECTIONS, OTHER_TEXT_SECTIONS
enum mismatch {
TEXTDATA_TO_ANY_INIT_EXIT,
XXXINIT_TO_SOME_INIT,
ANY_INIT_TO_ANY_EXIT,
ANY_EXIT_TO_ANY_INIT,
EXTABLE_TO_NON_TEXT,
};
/**
* Describe how to match sections on different criteria:
*
* @fromsec: Array of sections to be matched.
*
* @bad_tosec: Relocations applied to a section in @fromsec to a section in
* this array is forbidden (black-list). Can be empty.
*
* @good_tosec: Relocations applied to a section in @fromsec must be
* targeting sections in this array (white-list). Can be empty.
*
* @mismatch: Type of mismatch.
*/
struct sectioncheck {
const char *fromsec[20];
const char *bad_tosec[20];
const char *good_tosec[20];
enum mismatch mismatch;
};
static const struct sectioncheck sectioncheck[] = {
/* Do not reference init/exit code/data from
* normal code and data
*/
{
.fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL },
.bad_tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL },
.mismatch = TEXTDATA_TO_ANY_INIT_EXIT,
},
/* Do not reference init code/data from meminit code/data */
{
.fromsec = { ALL_XXXINIT_SECTIONS, NULL },
.bad_tosec = { INIT_SECTIONS, NULL },
.mismatch = XXXINIT_TO_SOME_INIT,
},
/* Do not use exit code/data from init code */
{
.fromsec = { ALL_INIT_SECTIONS, NULL },
.bad_tosec = { ALL_EXIT_SECTIONS, NULL },
.mismatch = ANY_INIT_TO_ANY_EXIT,
},
/* Do not use init code/data from exit code */
{
.fromsec = { ALL_EXIT_SECTIONS, NULL },
.bad_tosec = { ALL_INIT_SECTIONS, NULL },
.mismatch = ANY_EXIT_TO_ANY_INIT,
},
{
.fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
.bad_tosec = { INIT_SECTIONS, NULL },
.mismatch = ANY_INIT_TO_ANY_EXIT,
},
{
.fromsec = { "__ex_table", NULL },
/* If you're adding any new black-listed sections in here, consider
* adding a special 'printer' for them in scripts/check_extable.
*/
.bad_tosec = { ".altinstr_replacement", NULL },
.good_tosec = {ALL_TEXT_SECTIONS , NULL},
.mismatch = EXTABLE_TO_NON_TEXT,
}
};
static const struct sectioncheck *section_mismatch(
const char *fromsec, const char *tosec)
{
int i;
/*
* The target section could be the SHT_NUL section when we're
* handling relocations to un-resolved symbols, trying to match it
* doesn't make much sense and causes build failures on parisc
* architectures.
*/
if (*tosec == '\0')
return NULL;
for (i = 0; i < ARRAY_SIZE(sectioncheck); i++) {
const struct sectioncheck *check = &sectioncheck[i];
if (match(fromsec, check->fromsec)) {
if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
return check;
if (check->good_tosec[0] && !match(tosec, check->good_tosec))
return 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 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
*
* Pattern 5:
* GCC may optimize static inlines when fed constant arg(s) resulting
* in functions like cpumask_empty() -- generating an associated symbol
* cpumask_empty.constprop.3 that appears in the audit. If the const that
* is passed in comes from __init, like say nmi_ipi_mask, we get a
* meaningless section warning. May need to add isra symbols too...
* This pattern is identified by
* tosec = init section
* fromsec = text section
* refsymname = *.constprop.*
*
**/
static int secref_whitelist(const char *fromsec, const char *fromsym,
const char *tosec, const char *tosym)
{
/* Check for pattern 1 */
if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) &&
match(fromsec, PATTERNS(DATA_SECTIONS)) &&
strstarts(fromsym, "__param"))
return 0;
/* Check for pattern 1a */
if (strcmp(tosec, ".init.text") == 0 &&
match(fromsec, PATTERNS(DATA_SECTIONS)) &&
strstarts(fromsym, "__param_ops_"))
return 0;
/* symbols in data sections that may refer to any init/exit sections */
if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
match(fromsym, PATTERNS("*_ops", "*_probe", "*_console")))
return 0;
/*
* symbols in data sections must not refer to .exit.*, but there are
* quite a few offenders, so hide these unless for W=1 builds until
* these are fixed.
*/
if (!extra_warn &&
match(fromsec, PATTERNS(DATA_SECTIONS)) &&
match(tosec, PATTERNS(ALL_EXIT_SECTIONS)) &&
match(fromsym, PATTERNS("*driver")))
return 0;
/* Check for pattern 3 */
if (strstarts(fromsec, ".head.text") &&
match(tosec, PATTERNS(ALL_INIT_SECTIONS)))
return 0;
/* Check for pattern 4 */
if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext")))
return 0;
/* Check for pattern 5 */
if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) &&
match(tosec, PATTERNS(ALL_INIT_SECTIONS)) &&
match(fromsym, PATTERNS("*.constprop.*")))
return 0;
return 1;
}
static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr,
unsigned int secndx)
{
return symsearch_find_nearest(elf, addr, secndx, false, ~0);
}
static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym)
{
/* If the supplied symbol has a valid name, return it */
if (is_valid_name(elf, sym))
return sym;
/*
* Strive to find a better symbol name, but the resulting name may not
* match the symbol referenced in the original code.
*/
return symsearch_find_nearest(elf, addr, get_secindex(elf, sym),
true, 20);
}
static bool is_executable_section(struct elf_info *elf, unsigned int secndx)
{
if (secndx >= elf->num_sections)
return false;
return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0;
}
static void default_mismatch_handler(const char *modname, struct elf_info *elf,
const struct sectioncheck* const mismatch,
Elf_Sym *tsym,
unsigned int fsecndx, const char *fromsec, Elf_Addr faddr,
const char *tosec, Elf_Addr taddr)
{
Elf_Sym *from;
const char *tosym;
const char *fromsym;
from = find_fromsym(elf, faddr, fsecndx);
fromsym = sym_name(elf, from);
tsym = find_tosym(elf, taddr, tsym);
tosym = sym_name(elf, tsym);
/* check whitelist - we may ignore it */
if (!secref_whitelist(fromsec, fromsym, tosec, tosym))
return;
sec_mismatch_count++;
warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n",
modname, fromsym, (unsigned int)(faddr - from->st_value), fromsec, tosym, tosec);
if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) {
if (match(tosec, mismatch->bad_tosec))
fatal("The relocation at %s+0x%lx references\n"
"section \"%s\" which is black-listed.\n"
"Something is seriously wrong and should be fixed.\n"
"You might get more information about where this is\n"
"coming from by using scripts/check_extable.sh %s\n",
fromsec, (long)faddr, tosec, modname);
else if (is_executable_section(elf, get_secindex(elf, tsym)))
warn("The relocation at %s+0x%lx references\n"
"section \"%s\" which is not in the list of\n"
"authorized sections. If you're adding a new section\n"
"and/or if this reference is valid, add \"%s\" to the\n"
"list of authorized sections to jump to on fault.\n"
"This can be achieved by adding \"%s\" to\n"
"OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
fromsec, (long)faddr, tosec, tosec, tosec);
else
error("%s+0x%lx references non-executable section '%s'\n",
fromsec, (long)faddr, tosec);
}
}
static void check_export_symbol(struct module *mod, struct elf_info *elf,
Elf_Addr faddr, const char *secname,
Elf_Sym *sym)
{
static const char *prefix = "__export_symbol_";
const char *label_name, *name, *data;
Elf_Sym *label;
struct symbol *s;
bool is_gpl;
label = find_fromsym(elf, faddr, elf->export_symbol_secndx);
label_name = sym_name(elf, label);
if (!strstarts(label_name, prefix)) {
error("%s: .export_symbol section contains strange symbol '%s'\n",
mod->name, label_name);
return;
}
if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
ELF_ST_BIND(sym->st_info) != STB_WEAK) {
error("%s: local symbol '%s' was exported\n", mod->name,
label_name + strlen(prefix));
return;
}
name = sym_name(elf, sym);
if (strcmp(label_name + strlen(prefix), name)) {
error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n",
mod->name, name);
return;
}
data = sym_get_data(elf, label); /* license */
if (!strcmp(data, "GPL")) {
is_gpl = true;
} else if (!strcmp(data, "")) {
is_gpl = false;
} else {
error("%s: unknown license '%s' was specified for '%s'\n",
mod->name, data, name);
return;
}
data += strlen(data) + 1; /* namespace */
s = sym_add_exported(name, mod, is_gpl, data);
/*
* We need to be aware whether we are exporting a function or
* a data on some architectures.
*/
s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC);
/*
* For parisc64, symbols prefixed $$ from the library have the symbol type
* STT_LOPROC. They should be handled as functions too.
*/
if (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64 &&
elf->hdr->e_machine == EM_PARISC &&
ELF_ST_TYPE(sym->st_info) == STT_LOPROC)
s->is_func = true;
if (match(secname, PATTERNS(ALL_INIT_SECTIONS)))
warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n",
mod->name, name);
else if (match(secname, PATTERNS(ALL_EXIT_SECTIONS)))
warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n",
mod->name, name);
}
static void check_section_mismatch(struct module *mod, struct elf_info *elf,
Elf_Sym *sym,
unsigned int fsecndx, const char *fromsec,
Elf_Addr faddr, Elf_Addr taddr)
{
const char *tosec = sec_name(elf, get_secindex(elf, sym));
const struct sectioncheck *mismatch;
if (module_enabled && elf->export_symbol_secndx == fsecndx) {
check_export_symbol(mod, elf, faddr, tosec, sym);
return;
}
mismatch = section_mismatch(fromsec, tosec);
if (!mismatch)
return;
default_mismatch_handler(mod->name, elf, mismatch, sym,
fsecndx, fromsec, faddr,
tosec, taddr);
}
static Elf_Addr addend_386_rel(uint32_t *location, unsigned int r_type)
{
switch (r_type) {
case R_386_32:
return TO_NATIVE(*location);
case R_386_PC32:
return TO_NATIVE(*location) + 4;
}
return (Elf_Addr)(-1);
}
#ifndef R_ARM_CALL
#define R_ARM_CALL 28
#endif
#ifndef R_ARM_JUMP24
#define R_ARM_JUMP24 29
#endif
#ifndef R_ARM_THM_CALL
#define R_ARM_THM_CALL 10
#endif
#ifndef R_ARM_THM_JUMP24
#define R_ARM_THM_JUMP24 30
#endif
#ifndef R_ARM_MOVW_ABS_NC
#define R_ARM_MOVW_ABS_NC 43
#endif
#ifndef R_ARM_MOVT_ABS
#define R_ARM_MOVT_ABS 44
#endif
#ifndef R_ARM_THM_MOVW_ABS_NC
#define R_ARM_THM_MOVW_ABS_NC 47
#endif
#ifndef R_ARM_THM_MOVT_ABS
#define R_ARM_THM_MOVT_ABS 48
#endif
#ifndef R_ARM_THM_JUMP19
#define R_ARM_THM_JUMP19 51
#endif
static int32_t sign_extend32(int32_t value, int index)
{
uint8_t shift = 31 - index;
return (int32_t)(value << shift) >> shift;
}
static Elf_Addr addend_arm_rel(void *loc, Elf_Sym *sym, unsigned int r_type)
{
uint32_t inst, upper, lower, sign, j1, j2;
int32_t offset;
switch (r_type) {
case R_ARM_ABS32:
case R_ARM_REL32:
inst = TO_NATIVE(*(uint32_t *)loc);
return inst + sym->st_value;
case R_ARM_MOVW_ABS_NC:
case R_ARM_MOVT_ABS:
inst = TO_NATIVE(*(uint32_t *)loc);
offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff),
15);
return offset + sym->st_value;
case R_ARM_PC24:
case R_ARM_CALL:
case R_ARM_JUMP24:
inst = TO_NATIVE(*(uint32_t *)loc);
offset = sign_extend32((inst & 0x00ffffff) << 2, 25);
return offset + sym->st_value + 8;
case R_ARM_THM_MOVW_ABS_NC:
case R_ARM_THM_MOVT_ABS:
upper = TO_NATIVE(*(uint16_t *)loc);
lower = TO_NATIVE(*((uint16_t *)loc + 1));
offset = sign_extend32(((upper & 0x000f) << 12) |
((upper & 0x0400) << 1) |
((lower & 0x7000) >> 4) |
(lower & 0x00ff),
15);
return offset + sym->st_value;
case R_ARM_THM_JUMP19:
/*
* Encoding T3:
* S = upper[10]
* imm6 = upper[5:0]
* J1 = lower[13]
* J2 = lower[11]
* imm11 = lower[10:0]
* imm32 = SignExtend(S:J2:J1:imm6:imm11:'0')
*/
upper = TO_NATIVE(*(uint16_t *)loc);
lower = TO_NATIVE(*((uint16_t *)loc + 1));
sign = (upper >> 10) & 1;
j1 = (lower >> 13) & 1;
j2 = (lower >> 11) & 1;
offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) |
((upper & 0x03f) << 12) |
((lower & 0x07ff) << 1),
20);
return offset + sym->st_value + 4;
case R_ARM_THM_CALL:
case R_ARM_THM_JUMP24:
/*
* Encoding T4:
* S = upper[10]
* imm10 = upper[9:0]
* J1 = lower[13]
* J2 = lower[11]
* imm11 = lower[10:0]
* I1 = NOT(J1 XOR S)
* I2 = NOT(J2 XOR S)
* imm32 = SignExtend(S:I1:I2:imm10:imm11:'0')
*/
upper = TO_NATIVE(*(uint16_t *)loc);
lower = TO_NATIVE(*((uint16_t *)loc + 1));
sign = (upper >> 10) & 1;
j1 = (lower >> 13) & 1;
j2 = (lower >> 11) & 1;
offset = sign_extend32((sign << 24) |
((~(j1 ^ sign) & 1) << 23) |
((~(j2 ^ sign) & 1) << 22) |
((upper & 0x03ff) << 12) |
((lower & 0x07ff) << 1),
24);
return offset + sym->st_value + 4;
}
return (Elf_Addr)(-1);
}
static Elf_Addr addend_mips_rel(uint32_t *location, unsigned int r_type)
{
uint32_t inst;
inst = TO_NATIVE(*location);
switch (r_type) {
case R_MIPS_LO16:
return inst & 0xffff;
case R_MIPS_26:
return (inst & 0x03ffffff) << 2;
case R_MIPS_32:
return inst;
}
return (Elf_Addr)(-1);
}
#ifndef EM_RISCV
#define EM_RISCV 243
#endif
#ifndef R_RISCV_SUB32
#define R_RISCV_SUB32 39
#endif
#ifndef EM_LOONGARCH
#define EM_LOONGARCH 258
#endif
#ifndef R_LARCH_SUB32
#define R_LARCH_SUB32 55
#endif
static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info,
unsigned int *r_type, unsigned int *r_sym)
{
typedef struct {
Elf64_Word r_sym; /* Symbol index */
unsigned char r_ssym; /* Special symbol for 2nd relocation */
unsigned char r_type3; /* 3rd relocation type */
unsigned char r_type2; /* 2nd relocation type */
unsigned char r_type; /* 1st relocation type */
} Elf64_Mips_R_Info;
bool is_64bit = (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64);
if (elf->hdr->e_machine == EM_MIPS && is_64bit) {
Elf64_Mips_R_Info *mips64_r_info = (void *)&r_info;
*r_type = mips64_r_info->r_type;
*r_sym = TO_NATIVE(mips64_r_info->r_sym);
return;
}
if (is_64bit)
r_info = TO_NATIVE((Elf64_Xword)r_info);
else
r_info = TO_NATIVE((Elf32_Word)r_info);
*r_type = ELF_R_TYPE(r_info);
*r_sym = ELF_R_SYM(r_info);
}
static void section_rela(struct module *mod, struct elf_info *elf,
unsigned int fsecndx, const char *fromsec,
const Elf_Rela *start, const Elf_Rela *stop)
{
const Elf_Rela *rela;
for (rela = start; rela < stop; rela++) {
Elf_Sym *tsym;
Elf_Addr taddr, r_offset;
unsigned int r_type, r_sym;
r_offset = TO_NATIVE(rela->r_offset);
get_rel_type_and_sym(elf, rela->r_info, &r_type, &r_sym);
tsym = elf->symtab_start + r_sym;
taddr = tsym->st_value + TO_NATIVE(rela->r_addend);
switch (elf->hdr->e_machine) {
case EM_RISCV:
if (!strcmp("__ex_table", fromsec) &&
r_type == R_RISCV_SUB32)
continue;
break;
case EM_LOONGARCH:
if (!strcmp("__ex_table", fromsec) &&
r_type == R_LARCH_SUB32)
continue;
break;
}
check_section_mismatch(mod, elf, tsym,
fsecndx, fromsec, r_offset, taddr);
}
}
static void section_rel(struct module *mod, struct elf_info *elf,
unsigned int fsecndx, const char *fromsec,
const Elf_Rel *start, const Elf_Rel *stop)
{
const Elf_Rel *rel;
for (rel = start; rel < stop; rel++) {
Elf_Sym *tsym;
Elf_Addr taddr = 0, r_offset;
unsigned int r_type, r_sym;
void *loc;
r_offset = TO_NATIVE(rel->r_offset);
get_rel_type_and_sym(elf, rel->r_info, &r_type, &r_sym);
loc = sym_get_data_by_offset(elf, fsecndx, r_offset);
tsym = elf->symtab_start + r_sym;
switch (elf->hdr->e_machine) {
case EM_386:
taddr = addend_386_rel(loc, r_type);
break;
case EM_ARM:
taddr = addend_arm_rel(loc, tsym, r_type);
break;
case EM_MIPS:
taddr = addend_mips_rel(loc, r_type);
break;
default:
fatal("Please add code to calculate addend for this architecture\n");
}
check_section_mismatch(mod, elf, tsym,
fsecndx, fromsec, r_offset, taddr);
}
}
/**
* 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, struct elf_info *elf)
{
int i;
/* Walk through all sections */
for (i = 0; i < elf->num_sections; i++) {
Elf_Shdr *sechdr = &elf->sechdrs[i];
check_section(mod->name, elf, sechdr);
/* We want to process only relocation sections and not .init */
if (sechdr->sh_type == SHT_REL || sechdr->sh_type == SHT_RELA) {
/* section to which the relocation applies */
unsigned int secndx = sechdr->sh_info;
const char *secname = sec_name(elf, secndx);
const void *start, *stop;
/* If the section is known good, skip it */
if (match(secname, section_white_list))
continue;
start = sym_get_data_by_offset(elf, i, 0);
stop = start + sechdr->sh_size;
if (sechdr->sh_type == SHT_RELA)
section_rela(mod, elf, secndx, secname,
start, stop);
else
section_rel(mod, elf, secndx, secname,
start, stop);
}
}
}
static char *remove_dot(char *s)
{
size_t n = strcspn(s, ".");
if (n && s[n]) {
size_t m = strspn(s + n + 1, "0123456789");
if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0))
s[n] = 0;
}
return s;
}
/*
* The CRCs are recorded in .*.cmd files in the form of:
* #SYMVER <name> <crc>
*/
static void extract_crcs_for_object(const char *object, struct module *mod)
{
char cmd_file[PATH_MAX];
char *buf, *p;
const char *base;
int dirlen, ret;
base = strrchr(object, '/');
if (base) {
base++;
dirlen = base - object;
} else {
dirlen = 0;
base = object;
}
ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd",
dirlen, object, base);
if (ret >= sizeof(cmd_file)) {
error("%s: too long path was truncated\n", cmd_file);
return;
}
buf = read_text_file(cmd_file);
p = buf;
while ((p = strstr(p, "\n#SYMVER "))) {
char *name;
size_t namelen;
unsigned int crc;
struct symbol *sym;
name = p + strlen("\n#SYMVER ");
p = strchr(name, ' ');
if (!p)
break;
namelen = p - name;
p++;
if (!isdigit(*p))
continue; /* skip this line */
crc = strtoul(p, &p, 0);
if (*p != '\n')
continue; /* skip this line */
name[namelen] = '\0';
/*
* sym_find_with_module() may return NULL here.
* It typically occurs when CONFIG_TRIM_UNUSED_KSYMS=y.
* Since commit e1327a127703, genksyms calculates CRCs of all
* symbols, including trimmed ones. Ignore orphan CRCs.
*/
sym = sym_find_with_module(name, mod);
if (sym)
sym_set_crc(sym, crc);
}
free(buf);
}
/*
* The symbol versions (CRC) are recorded in the .*.cmd files.
* Parse them to retrieve CRCs for the current module.
*/
static void mod_set_crcs(struct module *mod)
{
char objlist[PATH_MAX];
char *buf, *p, *obj;
int ret;
if (mod->is_vmlinux) {
strcpy(objlist, ".vmlinux.objs");
} else {
/* objects for a module are listed in the *.mod file. */
ret = snprintf(objlist, sizeof(objlist), "%s.mod", mod->name);
if (ret >= sizeof(objlist)) {
error("%s: too long path was truncated\n", objlist);
return;
}
}
buf = read_text_file(objlist);
p = buf;
while ((obj = strsep(&p, "\n")) && obj[0])
extract_crcs_for_object(obj, mod);
free(buf);
}
static void read_symbols(const char *modname)
{
const char *symname;
char *version;
char *license;
char *namespace;
struct module *mod;
struct elf_info info = { };
Elf_Sym *sym;
if (!parse_elf(&info, modname))
return;
if (!strends(modname, ".o")) {
error("%s: filename must be suffixed with .o\n", modname);
return;
}
/* strip trailing .o */
mod = new_module(modname, strlen(modname) - strlen(".o"));
if (!mod->is_vmlinux) {
license = get_modinfo(&info, "license");
if (!license)
error("missing MODULE_LICENSE() in %s\n", modname);
while (license) {
if (!license_is_gpl_compatible(license)) {
mod->is_gpl_compatible = false;
break;
}
license = get_next_modinfo(&info, "license", license);
}
namespace = get_modinfo(&info, "import_ns");
while (namespace) {
add_namespace(&mod->imported_namespaces, namespace);
namespace = get_next_modinfo(&info, "import_ns",
namespace);
}
}
if (extra_warn && !get_modinfo(&info, "description"))
warn("missing MODULE_DESCRIPTION() in %s\n", modname);
for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
symname = remove_dot(info.strtab + sym->st_name);
handle_symbol(mod, &info, sym, symname);
handle_moddevtable(mod, &info, sym, symname);
}
check_sec_ref(mod, &info);
if (!mod->is_vmlinux) {
version = get_modinfo(&info, "version");
if (version || all_versions)
get_src_version(mod->name, mod->srcversion,
sizeof(mod->srcversion) - 1);
}
parse_elf_finish(&info);
if (modversions) {
/*
* 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.
*/
sym_add_unresolved("module_layout", mod, false);
mod_set_crcs(mod);
}
}
static void read_symbols_from_files(const char *filename)
{
FILE *in = stdin;
char fname[PATH_MAX];
in = fopen(filename, "r");
if (!in)
fatal("Can't open filenames file %s: %m", filename);
while (fgets(fname, PATH_MAX, in) != NULL) {
if (strends(fname, "\n"))
fname[strlen(fname)-1] = '\0';
read_symbols(fname);
}
fclose(in);
}
#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 = NOFAIL(realloc(buf->p, buf->size));
}
strncpy(buf->p + buf->pos, s, len);
buf->pos += len;
}
static void check_exports(struct module *mod)
{
struct symbol *s, *exp;
list_for_each_entry(s, &mod->unresolved_symbols, list) {
const char *basename;
exp = find_symbol(s->name);
if (!exp) {
if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS)
modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
"\"%s\" [%s.ko] undefined!\n",
s->name, mod->name);
continue;
}
if (exp->module == mod) {
error("\"%s\" [%s.ko] was exported without definition\n",
s->name, mod->name);
continue;
}
exp->used = true;
s->module = exp->module;
s->crc_valid = exp->crc_valid;
s->crc = exp->crc;
basename = strrchr(mod->name, '/');
if (basename)
basename++;
else
basename = mod->name;
if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
"module %s uses symbol %s from namespace %s, but does not import it.\n",
basename, exp->name, exp->namespace);
add_namespace(&mod->missing_namespaces, exp->namespace);
}
if (!mod->is_gpl_compatible && exp->is_gpl_only)
error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
basename, exp->name);
}
}
static void handle_white_list_exports(const char *white_list)
{
char *buf, *p, *name;
buf = read_text_file(white_list);
p = buf;
while ((name = strsep(&p, "\n"))) {
struct symbol *sym = find_symbol(name);
if (sym)
sym->used = true;
}
free(buf);
}
static void check_modname_len(struct module *mod)
{
const char *mod_name;
mod_name = strrchr(mod->name, '/');
if (mod_name == NULL)
mod_name = mod->name;
else
mod_name++;
if (strlen(mod_name) >= MODULE_NAME_LEN)
error("module name is too long [%s.ko]\n", mod->name);
}
/**
* Header for the generated file
**/
static void add_header(struct buffer *b, struct module *mod)
{
buf_printf(b, "#include <linux/module.h>\n");
/*
* Include build-salt.h after module.h in order to
* inherit the definitions.
*/
buf_printf(b, "#define INCLUDE_VERMAGIC\n");
buf_printf(b, "#include <linux/build-salt.h>\n");
buf_printf(b, "#include <linux/elfnote-lto.h>\n");
buf_printf(b, "#include <linux/export-internal.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, "#ifdef CONFIG_UNWINDER_ORC\n");
buf_printf(b, "#include <asm/orc_header.h>\n");
buf_printf(b, "ORC_HEADER;\n");
buf_printf(b, "#endif\n");
buf_printf(b, "\n");
buf_printf(b, "BUILD_SALT;\n");
buf_printf(b, "BUILD_LTO_INFO;\n");
buf_printf(b, "\n");
buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
buf_printf(b, "\n");
buf_printf(b, "__visible struct module __this_module\n");
buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
if (mod->has_init)
buf_printf(b, "\t.init = init_module,\n");
if (mod->has_cleanup)
buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
"\t.exit = cleanup_module,\n"
"#endif\n");
buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
buf_printf(b, "};\n");
if (!external_module)
buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
buf_printf(b,
"\n"
"#ifdef CONFIG_RETPOLINE\n"
"MODULE_INFO(retpoline, \"Y\");\n"
"#endif\n");
if (strstarts(mod->name, "drivers/staging"))
buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
if (strstarts(mod->name, "tools/testing"))
buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n");
}
static void add_exported_symbols(struct buffer *buf, struct module *mod)
{
struct symbol *sym;
/* generate struct for exported symbols */
buf_printf(buf, "\n");
list_for_each_entry(sym, &mod->exported_symbols, list) {
if (trim_unused_exports && !sym->used)
continue;
buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n",
sym->is_func ? "FUNC" : "DATA", sym->name,
sym->is_gpl_only ? "_gpl" : "", sym->namespace);
}
if (!modversions)
return;
/* record CRCs for exported symbols */
buf_printf(buf, "\n");
list_for_each_entry(sym, &mod->exported_symbols, list) {
if (trim_unused_exports && !sym->used)
continue;
if (!sym->crc_valid)
warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n"
"Is \"%s\" prototyped in <asm/asm-prototypes.h>?\n",
sym->name, mod->name, mod->is_vmlinux ? "" : ".ko",
sym->name);
buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n",
sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : "");
}
}
/**
* Record CRCs for unresolved symbols
**/
static void add_versions(struct buffer *b, struct module *mod)
{
struct symbol *s;
if (!modversions)
return;
buf_printf(b, "\n");
buf_printf(b, "static const struct modversion_info ____versions[]\n");
buf_printf(b, "__used __section(\"__versions\") = {\n");
list_for_each_entry(s, &mod->unresolved_symbols, list) {
if (!s->module)
continue;
if (!s->crc_valid) {
warn("\"%s\" [%s.ko] has no CRC!\n",
s->name, mod->name);
continue;
}
if (strlen(s->name) >= MODULE_NAME_LEN) {
error("too long symbol \"%s\" [%s.ko]\n",
s->name, mod->name);
break;
}
buf_printf(b, "\t{ %#8x, \"%s\" },\n",
s->crc, s->name);
}
buf_printf(b, "};\n");
}
static void add_depends(struct buffer *b, struct module *mod)
{
struct symbol *s;
int first = 1;
/* Clear ->seen flag of modules that own symbols needed by this. */
list_for_each_entry(s, &mod->unresolved_symbols, list) {
if (s->module)
s->module->seen = s->module->is_vmlinux;
}
buf_printf(b, "\n");
buf_printf(b, "MODULE_INFO(depends, \"");
list_for_each_entry(s, &mod->unresolved_symbols, list) {
const char *p;
if (!s->module)
continue;
if (s->module->seen)
continue;
s->module->seen = true;
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_buf(struct buffer *b, const char *fname)
{
FILE *file;
if (error_occurred)
return;
file = fopen(fname, "w");
if (!file) {
perror(fname);
exit(1);
}
if (fwrite(b->p, 1, b->pos, file) != b->pos) {
perror(fname);
exit(1);
}
if (fclose(file) != 0) {
perror(fname);
exit(1);
}
}
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:
write_buf(b, fname);
}
static void write_vmlinux_export_c_file(struct module *mod)
{
struct buffer buf = { };
buf_printf(&buf,
"#include <linux/export-internal.h>\n");
add_exported_symbols(&buf, mod);
write_if_changed(&buf, ".vmlinux.export.c");
free(buf.p);
}
/* do sanity checks, and generate *.mod.c file */
static void write_mod_c_file(struct module *mod)
{
struct buffer buf = { };
char fname[PATH_MAX];
int ret;
add_header(&buf, mod);
add_exported_symbols(&buf, mod);
add_versions(&buf, mod);
add_depends(&buf, mod);
add_moddevtable(&buf, mod);
add_srcversion(&buf, mod);
ret = snprintf(fname, sizeof(fname), "%s.mod.c", mod->name);
if (ret >= sizeof(fname)) {
error("%s: too long path was truncated\n", fname);
goto free;
}
write_if_changed(&buf, fname);
free:
free(buf.p);
}
/* parse Module.symvers file. line format:
* 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
**/
static void read_dump(const char *fname)
{
char *buf, *pos, *line;
buf = read_text_file(fname);
if (!buf)
/* No symbol versions, silently ignore */
return;
pos = buf;
while ((line = get_line(&pos))) {
char *symname, *namespace, *modname, *d, *export;
unsigned int crc;
struct module *mod;
struct symbol *s;
bool gpl_only;
if (!(symname = strchr(line, '\t')))
goto fail;
*symname++ = '\0';
if (!(modname = strchr(symname, '\t')))
goto fail;
*modname++ = '\0';
if (!(export = strchr(modname, '\t')))
goto fail;
*export++ = '\0';
if (!(namespace = strchr(export, '\t')))
goto fail;
*namespace++ = '\0';
crc = strtoul(line, &d, 16);
if (*symname == '\0' || *modname == '\0' || *d != '\0')
goto fail;
if (!strcmp(export, "EXPORT_SYMBOL_GPL")) {
gpl_only = true;
} else if (!strcmp(export, "EXPORT_SYMBOL")) {
gpl_only = false;
} else {
error("%s: unknown license %s. skip", symname, export);
continue;
}
mod = find_module(modname);
if (!mod) {
mod = new_module(modname, strlen(modname));
mod->from_dump = true;
}
s = sym_add_exported(symname, mod, gpl_only, namespace);
sym_set_crc(s, crc);
}
free(buf);
return;
fail:
free(buf);
fatal("parse error in symbol dump file\n");
}
static void write_dump(const char *fname)
{
struct buffer buf = { };
struct module *mod;
struct symbol *sym;
list_for_each_entry(mod, &modules, list) {
if (mod->from_dump)
continue;
list_for_each_entry(sym, &mod->exported_symbols, list) {
if (trim_unused_exports && !sym->used)
continue;
buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n",
sym->crc, sym->name, mod->name,
sym->is_gpl_only ? "_GPL" : "",
sym->namespace);
}
}
write_buf(&buf, fname);
free(buf.p);
}
static void write_namespace_deps_files(const char *fname)
{
struct module *mod;
struct namespace_list *ns;
struct buffer ns_deps_buf = {};
list_for_each_entry(mod, &modules, list) {
if (mod->from_dump || list_empty(&mod->missing_namespaces))
continue;
buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
list_for_each_entry(ns, &mod->missing_namespaces, list)
buf_printf(&ns_deps_buf, " %s", ns->namespace);
buf_printf(&ns_deps_buf, "\n");
}
write_if_changed(&ns_deps_buf, fname);
free(ns_deps_buf.p);
}
struct dump_list {
struct list_head list;
const char *file;
};
int main(int argc, char **argv)
{
struct module *mod;
char *missing_namespace_deps = NULL;
char *unused_exports_white_list = NULL;
char *dump_write = NULL, *files_source = NULL;
int opt;
LIST_HEAD(dump_lists);
struct dump_list *dl, *dl2;
while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:")) != -1) {
switch (opt) {
case 'e':
external_module = true;
break;
case 'i':
dl = NOFAIL(malloc(sizeof(*dl)));
dl->file = optarg;
list_add_tail(&dl->list, &dump_lists);
break;
case 'M':
module_enabled = true;
break;
case 'm':
modversions = true;
break;
case 'n':
ignore_missing_files = true;
break;
case 'o':
dump_write = optarg;
break;
case 'a':
all_versions = true;
break;
case 'T':
files_source = optarg;
break;
case 't':
trim_unused_exports = true;
break;
case 'u':
unused_exports_white_list = optarg;
break;
case 'W':
extra_warn = true;
break;
case 'w':
warn_unresolved = true;
break;
case 'E':
sec_mismatch_warn_only = false;
break;
case 'N':
allow_missing_ns_imports = true;
break;
case 'd':
missing_namespace_deps = optarg;
break;
default:
exit(1);
}
}
list_for_each_entry_safe(dl, dl2, &dump_lists, list) {
read_dump(dl->file);
list_del(&dl->list);
free(dl);
}
while (optind < argc)
read_symbols(argv[optind++]);
if (files_source)
read_symbols_from_files(files_source);
list_for_each_entry(mod, &modules, list) {
if (mod->from_dump || mod->is_vmlinux)
continue;
check_modname_len(mod);
check_exports(mod);
}
if (unused_exports_white_list)
handle_white_list_exports(unused_exports_white_list);
list_for_each_entry(mod, &modules, list) {
if (mod->from_dump)
continue;
if (mod->is_vmlinux)
write_vmlinux_export_c_file(mod);
else
write_mod_c_file(mod);
}
if (missing_namespace_deps)
write_namespace_deps_files(missing_namespace_deps);
if (dump_write)
write_dump(dump_write);
if (sec_mismatch_count && !sec_mismatch_warn_only)
error("Section mismatches detected.\n"
"Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
if (nr_unresolved > MAX_UNRESOLVED_REPORTS)
warn("suppressed %u unresolved symbol warnings because there were too many)\n",
nr_unresolved - MAX_UNRESOLVED_REPORTS);
return error_occurred ? 1 : 0;
}
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