modpost.c 41.8 KB
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/* Postprocess module symbol versions
 *
 * Copyright 2003       Kai Germaschewski
 * Copyright 2002-2004  Rusty Russell, IBM Corporation
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 * Copyright 2006       Sam Ravnborg
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 * 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"
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#include "../../include/linux/license.h"
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/* 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;
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/* If we are modposting external module set to 1 */
static int external_module = 0;
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/* Only warn about unresolved symbols */
static int warn_unresolved = 0;
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/* How a symbol is exported */
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enum export {
	export_plain,      export_unused,     export_gpl,
	export_unused_gpl, export_gpl_future, export_unknown
};
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void fatal(const char *fmt, ...)
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{
	va_list arglist;

	fprintf(stderr, "FATAL: ");

	va_start(arglist, fmt);
	vfprintf(stderr, fmt, arglist);
	va_end(arglist);

	exit(1);
}

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void warn(const char *fmt, ...)
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{
	va_list arglist;

	fprintf(stderr, "WARNING: ");

	va_start(arglist, fmt);
	vfprintf(stderr, fmt, arglist);
	va_end(arglist);
}

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void merror(const char *fmt, ...)
{
	va_list arglist;

	fprintf(stderr, "ERROR: ");

	va_start(arglist, fmt);
	vfprintf(stderr, fmt, arglist);
	va_end(arglist);
}

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static int is_vmlinux(const char *modname)
{
	const char *myname;

	if ((myname = strrchr(modname, '/')))
		myname++;
	else
		myname = modname;

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	return (strcmp(myname, "vmlinux") == 0) ||
	       (strcmp(myname, "vmlinux.o") == 0);
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}

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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;

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static struct module *find_module(char *modname)
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{
	struct module *mod;

	for (mod = modules; mod; mod = mod->next)
		if (strcmp(mod->name, modname) == 0)
			break;
	return mod;
}

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static struct module *new_module(char *modname)
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{
	struct module *mod;
	char *p, *s;
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	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;
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	mod->gpl_compatible = -1;
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	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;
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	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) **/
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	unsigned int preloaded:1;  /* 1 if symbol from Module.symvers */
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	enum export  export;       /* Type of export */
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	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);
}

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/**
 * 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)
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{
	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 */
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static struct symbol *new_symbol(const char *name, struct module *module,
				 enum export export)
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{
	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;
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	new->export = export;
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	return new;
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}

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static struct symbol *find_symbol(const char *name)
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{
	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;
}

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static struct {
	const char *str;
	enum export export;
} export_list[] = {
	{ .str = "EXPORT_SYMBOL",            .export = export_plain },
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	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
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	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
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	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
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	{ .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;
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	if (!s)
		return export_unknown;
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	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;
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	else if (sec == elf->export_unused_sec)
		return export_unused;
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	else if (sec == elf->export_gpl_sec)
		return export_gpl;
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	else if (sec == elf->export_unused_gpl_sec)
		return export_unused_gpl;
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	else if (sec == elf->export_gpl_future_sec)
		return export_gpl_future;
	else
		return export_unknown;
}

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/**
 * Add an exported symbol - it may have already been added without a
 * CRC, in this case just update the CRC
 **/
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static struct symbol *sym_add_exported(const char *name, struct module *mod,
				       enum export export)
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{
	struct symbol *s = find_symbol(name);

	if (!s) {
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		s = new_symbol(name, mod, export);
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	} else {
		if (!s->preloaded) {
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			warn("%s: '%s' exported twice. Previous export "
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			     "was in %s%s\n", mod->name, name,
			     s->module->name,
			     is_vmlinux(s->module->name) ?"":".ko");
		}
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	}
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	s->preloaded = 0;
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	s->vmlinux   = is_vmlinux(mod->name);
	s->kernel    = 0;
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	s->export    = export;
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	return s;
}

static void sym_update_crc(const char *name, struct module *mod,
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			   unsigned int crc, enum export export)
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{
	struct symbol *s = find_symbol(name);

	if (!s)
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		s = new_symbol(name, mod, export);
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	s->crc = crc;
	s->crc_valid = 1;
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}

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void *grab_file(const char *filename, unsigned long *size)
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{
	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;
}

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/**
  * 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)
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{
	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;
}

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void release_file(void *file, unsigned long size)
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{
	munmap(file, size);
}

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static int parse_elf(struct elf_info *info, const char *filename)
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{
	unsigned int i;
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	Elf_Ehdr *hdr;
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	Elf_Shdr *sechdrs;
	Elf_Sym  *sym;

	hdr = grab_file(filename, &info->size);
	if (!hdr) {
		perror(filename);
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		exit(1);
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	}
	info->hdr = hdr;
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	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;
	}
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	/* 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);
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	hdr->e_type     = TO_NATIVE(hdr->e_type);
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	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);
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		sechdrs[i].sh_info   = TO_NATIVE(sechdrs[i].sh_info);
		sechdrs[i].sh_addr   = TO_NATIVE(sechdrs[i].sh_addr);
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	}
	/* Find symbol table. */
	for (i = 1; i < hdr->e_shnum; i++) {
		const char *secstrings
			= (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
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		const char *secname;
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		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;
		}
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		secname = secstrings + sechdrs[i].sh_name;
		if (strcmp(secname, ".modinfo") == 0) {
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			info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
			info->modinfo_len = sechdrs[i].sh_size;
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		} else if (strcmp(secname, "__ksymtab") == 0)
			info->export_sec = i;
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		else if (strcmp(secname, "__ksymtab_unused") == 0)
			info->export_unused_sec = i;
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		else if (strcmp(secname, "__ksymtab_gpl") == 0)
			info->export_gpl_sec = i;
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		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
			info->export_unused_gpl_sec = i;
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		else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
			info->export_gpl_future_sec = i;

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		if (sechdrs[i].sh_type != SHT_SYMTAB)
			continue;

		info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
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		info->symtab_stop  = (void *)hdr + sechdrs[i].sh_offset
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			                         + sechdrs[i].sh_size;
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		info->strtab       = (void *)hdr +
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			             sechdrs[sechdrs[i].sh_link].sh_offset;
	}
	if (!info->symtab_start) {
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		fatal("%s has no symtab?\n", filename);
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	}
	/* 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);
	}
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	return 1;
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}

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static void parse_elf_finish(struct elf_info *info)
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{
	release_file(info->hdr, info->size);
}

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#define CRC_PFX     MODULE_SYMBOL_PREFIX "__crc_"
#define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
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static void handle_modversions(struct module *mod, struct elf_info *info,
			       Elf_Sym *sym, const char *symname)
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{
	unsigned int crc;
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	enum export export = export_from_sec(info, sym->st_shndx);
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	switch (sym->st_shndx) {
	case SHN_COMMON:
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		warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
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		break;
	case SHN_ABS:
		/* CRC'd symbol */
		if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
			crc = (unsigned int) sym->st_value;
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			sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
					export);
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		}
		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;
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/* 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
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		if (info->hdr->e_machine == EM_SPARC ||
		    info->hdr->e_machine == EM_SPARCV9) {
			/* Ignore register directives. */
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			if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
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				break;
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			if (symname[0] == '.') {
				char *munged = strdup(symname);
				munged[0] = '_';
				munged[1] = toupper(munged[1]);
				symname = munged;
			}
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		}
#endif
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		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) {
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			sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
					export);
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		}
		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;
	}
}

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/**
 * Parse tag=value strings from .modinfo section
 **/
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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;
}

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static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
			      const char *tag, char *info)
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{
	char *p;
	unsigned int taglen = strlen(tag);
	unsigned long size = modinfo_len;

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	if (info) {
		size -= info - (char *)modinfo;
		modinfo = next_string(info, &size);
	}

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	for (p = modinfo; p; p = next_string(p, &size)) {
		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
			return p + taglen + 1;
	}
	return NULL;
}

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static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
			 const char *tag)

{
	return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
}

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/**
 * Test if string s ends in string sub
 * return 0 if match
 **/
static int strrcmp(const char *s, const char *sub)
{
        int slen, sublen;
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	if (!s || !sub)
		return 1;
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	slen = strlen(s);
        sublen = strlen(sub);
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	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.
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 *
 * 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
 *
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 * 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
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 *   fromsec = .data*
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 *   atsym   =__param*
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 *
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 * Pattern 2:
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 *   Many drivers utilise a *driver container with references to
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 *   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:
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 *   tosec   = .init.text | .exit.text | .init.data
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 *   fromsec = .data | .data.rel | .data.rel.*
613
 *   atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console, *_timer
614 615
 *
 * Pattern 3:
616 617 618
 *   Whitelist all refereces from .text.head to .init.data
 *   Whitelist all refereces from .text.head to .init.text
 *
619
 * Pattern 4:
620 621 622 623 624 625 626
 *   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
627
 *
628
 **/
629
static int secref_whitelist(const char *modname, const char *tosec,
630 631
			    const char *fromsec, const char *atsym,
			    const char *refsymname)
632 633 634 635
{
	int f1 = 1, f2 = 1;
	const char **s;
	const char *pat2sym[] = {
636
		"driver",
637
		"_template", /* scsi uses *_template a lot */
638
		"_timer",    /* arm uses ops structures named _timer a lot */
639
		"_sht",      /* scsi also used *_sht to some extent */
640 641 642
		"_ops",
		"_probe",
		"_probe_one",
643
		"_console",
644 645
		NULL
	};
646

647 648 649 650 651 652 653
	const char *pat3refsym[] = {
		"__init_begin",
		"_sinittext",
		"_einittext",
		NULL
	};

654 655 656 657 658
	/* Check for pattern 0 */
	if ((strcmp(fromsec, ".text.init.refok") == 0) ||
	    (strcmp(fromsec, ".data.init.refok") == 0))
		return 1;

659 660 661
	/* Check for pattern 1 */
	if (strcmp(tosec, ".init.data") != 0)
		f1 = 0;
662
	if (strncmp(fromsec, ".data", strlen(".data")) != 0)
663 664 665 666 667 668 669 670
		f1 = 0;
	if (strncmp(atsym, "__param", strlen("__param")) != 0)
		f1 = 0;

	if (f1)
		return f1;

	/* Check for pattern 2 */
671
	if ((strcmp(tosec, ".init.text") != 0) &&
672 673
	    (strcmp(tosec, ".exit.text") != 0) &&
	    (strcmp(tosec, ".init.data") != 0))
674
		f2 = 0;
675 676 677
	if ((strcmp(fromsec, ".data") != 0) &&
	    (strcmp(fromsec, ".data.rel") != 0) &&
	    (strncmp(fromsec, ".data.rel.", strlen(".data.rel.")) != 0))
678 679 680 681 682
		f2 = 0;

	for (s = pat2sym; *s; s++)
		if (strrcmp(atsym, *s) == 0)
			f1 = 1;
683 684
	if (f1 && f2)
		return 1;
685

686 687 688 689 690 691
	/* Check for pattern 3 */
	if ((strcmp(fromsec, ".text.head") == 0) &&
		((strcmp(tosec, ".init.data") == 0) ||
		(strcmp(tosec, ".init.text") == 0)))
	return 1;

692
	/* Check for pattern 4 */
693 694 695 696
	for (s = pat3refsym; *s; s++)
		if (strcmp(refsymname, *s) == 0)
			return 1;

697
	return 0;
698 699
}

700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716
/**
 * 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;
717 718
		if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
			continue;
719 720 721 722 723 724
		if (sym->st_value == addr)
			return sym;
	}
	return NULL;
}

725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748
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);
}

749
/*
750 751 752 753
 * 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.
754 755 756 757 758 759 760 761 762 763 764
 **/
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;
765

766 767 768 769 770 771 772 773 774 775 776
	*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;
777 778
		if (!is_valid_name(elf, sym))
			continue;
779 780 781 782 783
		if (sym->st_value <= addr) {
			if ((addr - sym->st_value) < beforediff) {
				beforediff = addr - sym->st_value;
				*before = sym;
			}
784
			else if ((addr - sym->st_value) == beforediff) {
785
				*before = sym;
786
			}
787 788 789 790 791 792 793
		}
		else
		{
			if ((sym->st_value - addr) < afterdiff) {
				afterdiff = sym->st_value - addr;
				*after = sym;
			}
794
			else if ((sym->st_value - addr) == afterdiff) {
795
				*after = sym;
796
			}
797 798 799 800 801 802 803
		}
	}
}

/**
 * Print a warning about a section mismatch.
 * Try to find symbols near it so user can find it.
804
 * Check whitelist before warning - it may be a false positive.
805 806 807 808
 **/
static void warn_sec_mismatch(const char *modname, const char *fromsec,
			      struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
{
809 810 811
	const char *refsymname = "";
	Elf_Sym *before, *after;
	Elf_Sym *refsym;
812 813 814 815 816
	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;
817

818 819
	find_symbols_between(elf, r.r_offset, fromsec, &before, &after);

820 821 822
	refsym = find_elf_symbol(elf, r.r_addend, sym);
	if (refsym && strlen(elf->strtab + refsym->st_name))
		refsymname = elf->strtab + refsym->st_name;
823 824

	/* check whitelist - we may ignore it */
825
	if (before &&
826
	    secref_whitelist(modname, secname, fromsec,
827
			     elf->strtab + before->st_name, refsymname))
828
		return;
829

830
	if (before && after) {
831 832 833 834
		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,
835 836 837
		     elf->strtab + before->st_name,
		     elf->strtab + after->st_name);
	} else if (before) {
838 839 840 841 842
		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);
843
	} else if (after) {
844
		warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
845
		     "before '%s' (at offset -0x%llx)\n",
846 847 848
		     modname, fromsec, (unsigned long long)r.r_offset,
		     secname, refsymname,
		     elf->strtab + after->st_name);
849
	} else {
850 851 852
		warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n",
		     modname, fromsec, (unsigned long long)r.r_offset,
		     secname, refsymname);
853 854 855
	}
}

856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884
static unsigned int *reloc_location(struct elf_info *elf,
					   int rsection, Elf_Rela *r)
{
	Elf_Shdr *sechdrs = elf->sechdrs;
	int section = sechdrs[rsection].sh_info;

	return (void *)elf->hdr + sechdrs[section].sh_offset +
		(r->r_offset - sechdrs[section].sh_addr);
}

static int addend_386_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
{
	unsigned int r_typ = ELF_R_TYPE(r->r_info);
	unsigned int *location = reloc_location(elf, rsection, r);

	switch (r_typ) {
	case R_386_32:
		r->r_addend = TO_NATIVE(*location);
		break;
	case R_386_PC32:
		r->r_addend = TO_NATIVE(*location) + 4;
		/* For CONFIG_RELOCATABLE=y */
		if (elf->hdr->e_type == ET_EXEC)
			r->r_addend += r->r_offset;
		break;
	}
	return 0;
}

885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904
static int addend_arm_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
{
	unsigned int r_typ = ELF_R_TYPE(r->r_info);

	switch (r_typ) {
	case R_ARM_ABS32:
		/* From ARM ABI: (S + A) | T */
		r->r_addend = (int)(long)(elf->symtab_start + ELF_R_SYM(r->r_info));
		break;
	case R_ARM_PC24:
		/* From ARM ABI: ((S + A) | T) - P */
		r->r_addend = (int)(long)(elf->hdr + elf->sechdrs[rsection].sh_offset +
		                          (r->r_offset - elf->sechdrs[rsection].sh_addr));
		break;
	default:
		return 1;
	}
	return 0;
}

905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927
static int addend_mips_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
{
	unsigned int r_typ = ELF_R_TYPE(r->r_info);
	unsigned int *location = reloc_location(elf, rsection, r);
	unsigned int inst;

	if (r_typ == R_MIPS_HI16)
		return 1;	/* skip this */
	inst = TO_NATIVE(*location);
	switch (r_typ) {
	case R_MIPS_LO16:
		r->r_addend = inst & 0xffff;
		break;
	case R_MIPS_26:
		r->r_addend = (inst & 0x03ffffff) << 2;
		break;
	case R_MIPS_32:
		r->r_addend = inst;
		break;
	}
	return 0;
}

928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950
/**
 * 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;
951

952 953
	/* Walk through all sections */
	for (i = 0; i < hdr->e_shnum; i++) {
954 955 956
		const char *name = secstrings + sechdrs[i].sh_name;
		const char *secname;
		Elf_Rela r;
957
		unsigned int r_sym;
958
		/* We want to process only relocation sections and not .init */
959 960 961 962 963 964 965
		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;
966

967 968
			for (rela = start; rela < stop; rela++) {
				r.r_offset = TO_NATIVE(rela->r_offset);
969 970
#if KERNEL_ELFCLASS == ELFCLASS64
				if (hdr->e_machine == EM_MIPS) {
971
					unsigned int r_typ;
972 973
					r_sym = ELF64_MIPS_R_SYM(rela->r_info);
					r_sym = TO_NATIVE(r_sym);
974 975
					r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
					r.r_info = ELF64_R_INFO(r_sym, r_typ);
976 977 978 979 980 981 982 983
				} 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
984
				r.r_addend = TO_NATIVE(rela->r_addend);
985
				sym = elf->symtab_start + r_sym;
986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001
				/* 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))
1002 1003
				continue;

1004 1005
			for (rel = start; rel < stop; rel++) {
				r.r_offset = TO_NATIVE(rel->r_offset);
1006 1007
#if KERNEL_ELFCLASS == ELFCLASS64
				if (hdr->e_machine == EM_MIPS) {
1008
					unsigned int r_typ;
1009 1010
					r_sym = ELF64_MIPS_R_SYM(rel->r_info);
					r_sym = TO_NATIVE(r_sym);
1011 1012
					r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
					r.r_info = ELF64_R_INFO(r_sym, r_typ);
1013 1014 1015 1016 1017 1018 1019 1020
				} 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
1021
				r.r_addend = 0;
1022 1023 1024 1025 1026
				switch (hdr->e_machine) {
				case EM_386:
					if (addend_386_rel(elf, i, &r))
						continue;
					break;
1027 1028 1029 1030
				case EM_ARM:
					if(addend_arm_rel(elf, i, &r))
						continue;
					break;
1031 1032 1033 1034 1035
				case EM_MIPS:
					if (addend_mips_rel(elf, i, &r))
						continue;
					break;
				}
1036
				sym = elf->symtab_start + r_sym;
1037 1038 1039 1040 1041 1042 1043 1044 1045 1046
				/* 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);
			}
1047 1048 1049 1050
		}
	}
}

1051 1052 1053 1054 1055 1056 1057 1058 1059
/*
 * Identify sections from which references to either a
 * .init or 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
1060
 */
1061 1062 1063 1064 1065 1066 1067 1068 1069 1070
static int initexit_section_ref_ok(const char *name)
{
	const char **s;
	/* Absolute section names */
	const char *namelist1[] = {
		"__bug_table",		/* used by powerpc for BUG() */
		"__ex_table",
		".altinstructions",
		".cranges",		/* used by sh64 */
		".fixup",
1071 1072
		".machvec",		/* ia64 + powerpc uses these */
		".machine.desc",
1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107
		".opd",			/* See comment [OPD] */
		".parainstructions",
		".pdr",
		".plt",			/* seen on ARCH=um build on x86_64. Harmless */
		".smp_locks",
		".stab",
		NULL
	};
	/* Start of section names */
	const char *namelist2[] = {
		".debug",
		".eh_frame",
		".note",		/* ignore ELF notes - may contain anything */
		".got",			/* powerpc - global offset table */
		".toc",			/* powerpc - table of contents */
		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;
}

1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123
/**
 * 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;
}

1124
/*
1125
 * Identify sections from which references to a .init section is OK.
1126
 *
1127 1128 1129 1130 1131
 * 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:
1132
 *
1133 1134 1135 1136 1137
 * 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.
1138
 */
1139 1140 1141 1142 1143
static int init_section_ref_ok(const char *name)
{
	const char **s;
	/* Absolute section names */
	const char *namelist1[] = {
1144 1145
		"__ftr_fixup",		/* powerpc cpu feature fixup */
		"__fw_ftr_fixup",	/* powerpc firmware feature fixup */
1146 1147 1148 1149
		"__param",
		".data.rel.ro",		/* used by parisc64 */
		".init",
		".text.lock",
1150 1151 1152 1153 1154
		NULL
	};
	/* Start of section names */
	const char *namelist2[] = {
		".init.",
1155
		".pci_fixup",
1156
		".rodata",
1157 1158 1159
		NULL
	};

1160 1161 1162
	if (initexit_section_ref_ok(name))
		return 1;

1163 1164 1165
	for (s = namelist1; *s; s++)
		if (strcmp(*s, name) == 0)
			return 1;
1166
	for (s = namelist2; *s; s++)
1167 1168
		if (strncmp(*s, name, strlen(*s)) == 0)
			return 1;
1169 1170 1171 1172

	/* If section name ends with ".init" we allow references
	 * as is the case with .initcallN.init, .early_param.init, .taglist.init etc
	 */
1173 1174
	if (strrcmp(name, ".init") == 0)
		return 1;
1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191
	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;
1192

1193 1194 1195 1196
}

/*
 * Identify sections from which references to a .exit section is OK.
1197
 */
1198 1199 1200 1201 1202 1203
static int exit_section_ref_ok(const char *name)
{
	const char **s;
	/* Absolute section names */
	const char *namelist1[] = {
		".exit.data",
1204 1205
		".exit.text",
		".exitcall.exit",
1206
		".rodata",
1207 1208
		NULL
	};
1209

1210 1211 1212
	if (initexit_section_ref_ok(name))
		return 1;

1213 1214 1215 1216 1217 1218
	for (s = namelist1; *s; s++)
		if (strcmp(*s, name) == 0)
			return 1;
	return 0;
}

1219
static void read_symbols(char *modname)
L
Linus Torvalds 已提交
1220 1221 1222
{
	const char *symname;
	char *version;
1223
	char *license;
L
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1224 1225 1226 1227
	struct module *mod;
	struct elf_info info = { };
	Elf_Sym *sym;

1228 1229
	if (!parse_elf(&info, modname))
		return;
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1230 1231 1232 1233 1234 1235 1236 1237 1238 1239

	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;
	}

1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251
	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);
	}

L
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1252 1253 1254 1255 1256 1257
	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);
	}
1258 1259
	check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
	check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
L
Linus Torvalds 已提交
1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284

	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 */

1285 1286
void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
						      const char *fmt, ...)
L
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{
	char tmp[SZ];
	int len;
	va_list ap;
1291

L
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	va_start(ap, fmt);
	len = vsnprintf(tmp, SZ, fmt, ap);
1294
	buf_write(buf, tmp, len);
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	va_end(ap);
}

1298
void buf_write(struct buffer *buf, const char *s, int len)
L
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1299 1300
{
	if (buf->size - buf->pos < len) {
1301
		buf->size += len + SZ;
L
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		buf->p = realloc(buf->p, buf->size);
	}
	strncpy(buf->p + buf->pos, s, len);
	buf->pos += len;
}

1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349
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)
1350 1351 1352 1353
{
	struct symbol *s, *exp;

	for (s = mod->unres; s; s = s->next) {
A
Andrew Morton 已提交
1354
		const char *basename;
1355 1356 1357
		exp = find_symbol(s->name);
		if (!exp || exp->module == mod)
			continue;
A
Andrew Morton 已提交
1358
		basename = strrchr(mod->name, '/');
1359 1360
		if (basename)
			basename++;
1361 1362 1363 1364 1365
		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);
1366 1367 1368
        }
}

1369 1370 1371 1372
/**
 * Header for the generated file
 **/
static void add_header(struct buffer *b, struct module *mod)
L
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1373 1374 1375 1376 1377 1378 1379 1380 1381
{
	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");
1382
	buf_printf(b, " .name = KBUILD_MODNAME,\n");
L
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1383 1384 1385 1386 1387 1388
	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");
1389
	buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
L
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	buf_printf(b, "};\n");
}

1393 1394 1395
/**
 * Record CRCs for unresolved symbols
 **/
1396
static int add_versions(struct buffer *b, struct module *mod)
L
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1397 1398
{
	struct symbol *s, *exp;
1399
	int err = 0;
L
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1400 1401 1402 1403

	for (s = mod->unres; s; s = s->next) {
		exp = find_symbol(s->name);
		if (!exp || exp->module == mod) {
1404
			if (have_vmlinux && !s->weak) {
1405 1406 1407 1408 1409 1410 1411 1412
				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;
				}
1413
			}
L
Linus Torvalds 已提交
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			continue;
		}
		s->module = exp->module;
		s->crc_valid = exp->crc_valid;
		s->crc = exp->crc;
	}

	if (!modversions)
1422
		return err;
L
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1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433

	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) {
1434
			warn("\"%s\" [%s.ko] has no CRC!\n",
L
Linus Torvalds 已提交
1435 1436 1437 1438 1439 1440 1441
				s->name, mod->name);
			continue;
		}
		buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
	}

	buf_printf(b, "};\n");
1442 1443

	return err;
L
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1444 1445
}

1446 1447
static void add_depends(struct buffer *b, struct module *mod,
			struct module *modules)
L
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1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462
{
	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) {
1463
		const char *p;
L
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1464 1465 1466 1467 1468 1469 1470
		if (!s->module)
			continue;

		if (s->module->seen)
			continue;

		s->module->seen = 1;
1471 1472 1473 1474 1475
		if ((p = strrchr(s->module->name, '/')) != NULL)
			p++;
		else
			p = s->module->name;
		buf_printf(b, "%s%s", first ? "" : ",", p);
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		first = 0;
	}
	buf_printf(b, "\";\n");
}

1481
static void add_srcversion(struct buffer *b, struct module *mod)
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{
	if (mod->srcversion[0]) {
		buf_printf(b, "\n");
		buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
			   mod->srcversion);
	}
}

1490
static void write_if_changed(struct buffer *b, const char *fname)
L
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1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533
{
	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);
}

1534
/* parse Module.symvers file. line format:
S
Sam Ravnborg 已提交
1535
 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1536
 **/
1537
static void read_dump(const char *fname, unsigned int kernel)
L
Linus Torvalds 已提交
1538 1539 1540 1541 1542 1543 1544 1545 1546 1547
{
	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))) {
S
Sam Ravnborg 已提交
1548
		char *symname, *modname, *d, *export, *end;
L
Linus Torvalds 已提交
1549 1550
		unsigned int crc;
		struct module *mod;
1551
		struct symbol *s;
L
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1552 1553 1554 1555 1556 1557 1558

		if (!(symname = strchr(line, '\t')))
			goto fail;
		*symname++ = '\0';
		if (!(modname = strchr(symname, '\t')))
			goto fail;
		*modname++ = '\0';
1559
		if ((export = strchr(modname, '\t')) != NULL)
1560
			*export++ = '\0';
S
Sam Ravnborg 已提交
1561 1562
		if (export && ((end = strchr(export, '\t')) != NULL))
			*end = '\0';
L
Linus Torvalds 已提交
1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573
		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;
		}
1574
		s = sym_add_exported(symname, mod, export_no(export));
1575 1576
		s->kernel    = kernel;
		s->preloaded = 1;
1577
		sym_update_crc(symname, mod, crc, export_no(export));
L
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1578 1579 1580 1581 1582 1583
	}
	return;
fail:
	fatal("parse error in symbol dump file\n");
}

1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595
/* 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;
}
1596

1597
static void write_dump(const char *fname)
L
Linus Torvalds 已提交
1598 1599 1600 1601 1602 1603 1604 1605
{
	struct buffer buf = { };
	struct symbol *symbol;
	int n;

	for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
		symbol = symbolhash[n];
		while (symbol) {
1606
			if (dump_sym(symbol))
1607
				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1608
					symbol->crc, symbol->name,
1609 1610
					symbol->module->name,
					export_str(symbol->export));
L
Linus Torvalds 已提交
1611 1612 1613 1614 1615 1616
			symbol = symbol->next;
		}
	}
	write_if_changed(&buf, fname);
}

1617
int main(int argc, char **argv)
L
Linus Torvalds 已提交
1618 1619 1620 1621
{
	struct module *mod;
	struct buffer buf = { };
	char fname[SZ];
1622 1623
	char *kernel_read = NULL, *module_read = NULL;
	char *dump_write = NULL;
L
Linus Torvalds 已提交
1624
	int opt;
1625
	int err;
L
Linus Torvalds 已提交
1626

1627
	while ((opt = getopt(argc, argv, "i:I:mo:aw")) != -1) {
L
Linus Torvalds 已提交
1628 1629
		switch(opt) {
			case 'i':
1630 1631 1632 1633 1634
				kernel_read = optarg;
				break;
			case 'I':
				module_read = optarg;
				external_module = 1;
L
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1635 1636 1637 1638 1639 1640 1641 1642 1643 1644
				break;
			case 'm':
				modversions = 1;
				break;
			case 'o':
				dump_write = optarg;
				break;
			case 'a':
				all_versions = 1;
				break;
1645 1646 1647
			case 'w':
				warn_unresolved = 1;
				break;
L
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1648 1649 1650 1651 1652
			default:
				exit(1);
		}
	}

1653 1654 1655 1656
	if (kernel_read)
		read_dump(kernel_read, 1);
	if (module_read)
		read_dump(module_read, 0);
L
Linus Torvalds 已提交
1657 1658 1659 1660 1661

	while (optind < argc) {
		read_symbols(argv[optind++]);
	}

1662 1663 1664
	for (mod = modules; mod; mod = mod->next) {
		if (mod->skip)
			continue;
1665
		check_exports(mod);
1666 1667
	}

1668 1669
	err = 0;

L
Linus Torvalds 已提交
1670 1671 1672 1673 1674 1675 1676
	for (mod = modules; mod; mod = mod->next) {
		if (mod->skip)
			continue;

		buf.pos = 0;

		add_header(&buf, mod);
1677
		err |= add_versions(&buf, mod);
L
Linus Torvalds 已提交
1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688
		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);

1689
	return err;
L
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1690
}