modpost.c 48.8 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 2006-2008  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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/* Warn about section mismatch in vmlinux if set to 1 */
static int vmlinux_section_warnings = 1;
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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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static int sec_mismatch_count = 0;
static int sec_mismatch_verbose = 1;

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enum export {
	export_plain,      export_unused,     export_gpl,
	export_unused_gpl, export_gpl_future, export_unknown
};
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#define PRINTF __attribute__ ((format (printf, 1, 2)))

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

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	myname = strrchr(modname, '/');
	if (myname)
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		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)
{
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	if (!ptr)
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		fatal("modpost: Memory allocation failure: %s.\n", expr);
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	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 */
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	s = strrchr(p, '.');
	if (s != NULL)
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		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. */
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	for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
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		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++;

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	for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
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		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;
}

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static enum export export_no(const char *s)
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{
	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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		} else {
			/* In case Modules.symvers was out of date */
			s->module = mod;
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		}
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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.
  **/
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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;

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	for (; *pos < size ; (*pos)++) {
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		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;

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	/* Check if file offset is correct */
	if (hdr->e_shoff > info->size) {
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		fatal("section header offset=%lu in file '%s' is bigger than "
		      "filesize=%lu\n", (unsigned long)hdr->e_shoff,
		      filename, info->size);
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		return 0;
	}

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	/* 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) {
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			fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
			      "sizeof(*hrd)=%zu\n", filename,
			      (unsigned long)sechdrs[i].sh_offset,
			      sizeof(*hdr));
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			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;
	}
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	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,
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			   strlen(MODULE_SYMBOL_PREFIX)) == 0) {
			mod->unres =
			  alloc_symbol(symname +
			               strlen(MODULE_SYMBOL_PREFIX),
			               ELF_ST_BIND(sym->st_info) == STB_WEAK,
			               mod->unres);
		}
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		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;
}

581 582 583 584 585 586 587
static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
			 const char *tag)

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

588 589 590 591 592 593
/**
 * Test if string s ends in string sub
 * return 0 if match
 **/
static int strrcmp(const char *s, const char *sub)
{
S
Sam Ravnborg 已提交
594
	int slen, sublen;
595

596 597
	if (!s || !sub)
		return 1;
598

599
	slen = strlen(s);
S
Sam Ravnborg 已提交
600
	sublen = strlen(sub);
601

602 603 604
	if ((slen == 0) || (sublen == 0))
		return 1;

S
Sam Ravnborg 已提交
605 606
	if (sublen > slen)
		return 1;
607

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Sam Ravnborg 已提交
608
	return memcmp(s + slen - sublen, sub, sublen);
609 610
}

611 612
static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
{
613 614 615
	if (sym)
		return elf->strtab + sym->st_name;
	else
616
		return "(unknown)";
617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633
}

static const char *sec_name(struct elf_info *elf, int shndx)
{
	Elf_Shdr *sechdrs = elf->sechdrs;
	return (void *)elf->hdr +
	        elf->sechdrs[elf->hdr->e_shstrndx].sh_offset +
	        sechdrs[shndx].sh_name;
}

static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
{
	return (void *)elf->hdr +
	        elf->sechdrs[elf->hdr->e_shstrndx].sh_offset +
	        sechdr->sh_name;
}

634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653
/* if sym is empty or point to a string
 * like ".[0-9]+" then return 1.
 * This is the optional prefix added by ld to some sections
 */
static int number_prefix(const char *sym)
{
	if (*sym++ == '\0')
		return 1;
	if (*sym != '.')
		return 0;
	do {
		char c = *sym++;
		if (c < '0' || c > '9')
			return 0;
	} while (*sym);
	return 1;
}

/* The pattern is an array of simple patterns.
 * "foo" will match an exact string equal to "foo"
654
 * "*foo" will match a string that ends with "foo"
655 656 657 658 659 660 661 662 663 664 665 666 667
 * "foo*" will match a string that begins with "foo"
 * "foo$" will match a string equal to "foo" or "foo.1"
 *   where the '1' can be any number including several digits.
 *   The $ syntax is for sections where ld append a dot number
 *   to make section name unique.
 */
int match(const char *sym, const char * const pat[])
{
	const char *p;
	while (*pat) {
		p = *pat++;
		const char *endp = p + strlen(p) - 1;

668 669 670 671 672
		/* "*foo" */
		if (*p == '*') {
			if (strrcmp(sym, p + 1) == 0)
				return 1;
		}
673
		/* "foo*" */
674
		else if (*endp == '*') {
675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698
			if (strncmp(sym, p, strlen(p) - 1) == 0)
				return 1;
		}
		/* "foo$" */
		else if (*endp == '$') {
			if (strncmp(sym, p, strlen(p) - 1) == 0) {
				if (number_prefix(sym + strlen(p) - 1))
					return 1;
			}
		}
		/* no wildcards */
		else {
			if (strcmp(p, sym) == 0)
				return 1;
		}
	}
	/* no match */
	return 0;
}

/* sections that we do not want to do full section mismatch check on */
static const char *section_white_list[] =
	{ ".debug*", ".stab*", ".note*", ".got*", ".toc*", NULL };

699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735
/*
 * Is this section one we do not want to check?
 * This is often debug sections.
 * If we are going to check this section then
 * test if section name ends with a dot and a number.
 * This is used to find sections where the linker have
 * appended a dot-number to make the name unique.
 * The cause of this is often a section specified in assembler
 * without "ax" / "aw" and the same section used in .c
 * code where gcc add these.
 */
static int check_section(const char *modname, const char *sec)
{
	const char *e = sec + strlen(sec) - 1;
	if (match(sec, section_white_list))
		return 1;

	if (*e && isdigit(*e)) {
		/* consume all digits */
		while (*e && e != sec && isdigit(*e))
			e--;
		if (*e == '.') {
			warn("%s (%s): unexpected section name.\n"
			     "The (.[number]+) following section name are "
			     "ld generated and not expected.\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);
		}
	}
	return 0;
}



736 737 738 739
#define ALL_INIT_DATA_SECTIONS \
	".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
#define ALL_EXIT_DATA_SECTIONS \
	".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
740

741 742 743 744
#define ALL_INIT_TEXT_SECTIONS \
	".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
#define ALL_EXIT_TEXT_SECTIONS \
	".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
745

746 747
#define ALL_INIT_SECTIONS ALL_INIT_DATA_SECTIONS, ALL_INIT_TEXT_SECTIONS
#define ALL_EXIT_SECTIONS ALL_EXIT_DATA_SECTIONS, ALL_EXIT_TEXT_SECTIONS
748

749
#define DATA_SECTIONS ".data$", ".data.rel$"
750 751
#define TEXT_SECTIONS ".text$"

752 753 754 755 756 757 758 759 760 761
#define INIT_SECTIONS      ".init.data$", ".init.text$"
#define DEV_INIT_SECTIONS  ".devinit.data$", ".devinit.text$"
#define CPU_INIT_SECTIONS  ".cpuinit.data$", ".cpuinit.text$"
#define MEM_INIT_SECTIONS  ".meminit.data$", ".meminit.text$"

#define EXIT_SECTIONS      ".exit.data$", ".exit.text$"
#define DEV_EXIT_SECTIONS  ".devexit.data$", ".devexit.text$"
#define CPU_EXIT_SECTIONS  ".cpuexit.data$", ".cpuexit.text$"
#define MEM_EXIT_SECTIONS  ".memexit.data$", ".memexit.text$"

762
/* init data sections */
763
static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
764 765

/* all init sections */
766
static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
767 768 769

/* All init and exit sections (code + data) */
static const char *init_exit_sections[] =
770
	{ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802

/* data section */
static const char *data_sections[] = { DATA_SECTIONS, NULL };

/* sections that may refer to an init/exit section with no warning */
static const char *initref_sections[] =
{
	".text.init.refok*",
	".exit.text.refok*",
	".data.init.refok*",
	NULL
};


/* symbols in .data that may refer to init/exit sections */
static const char *symbol_white_list[] =
{
	"*driver",
	"*_template", /* scsi uses *_template a lot */
	"*_timer",    /* arm uses ops structures named _timer a lot */
	"*_sht",      /* scsi also used *_sht to some extent */
	"*_ops",
	"*_probe",
	"*_probe_one",
	"*_console",
	NULL
};

static const char *head_sections[] = { ".head.text*", NULL };
static const char *linker_symbols[] =
	{ "__init_begin", "_sinittext", "_einittext", NULL };

803 804 805 806 807 808 809 810 811 812 813 814 815
enum mismatch {
	NO_MISMATCH,
	TEXT_TO_INIT,
	DATA_TO_INIT,
	TEXT_TO_EXIT,
	DATA_TO_EXIT,
	XXXINIT_TO_INIT,
	XXXEXIT_TO_EXIT,
	INIT_TO_EXIT,
	EXIT_TO_INIT,
	EXPORT_TO_INIT_EXIT,
};

816 817 818
struct sectioncheck {
	const char *fromsec[20];
	const char *tosec[20];
819
	enum mismatch mismatch;
820 821 822 823 824 825 826
};

const struct sectioncheck sectioncheck[] = {
/* Do not reference init/exit code/data from
 * normal code and data
 */
{
827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844
	.fromsec = { TEXT_SECTIONS, NULL },
	.tosec   = { ALL_INIT_SECTIONS, NULL },
	.mismatch = TEXT_TO_INIT,
},
{
	.fromsec = { DATA_SECTIONS, NULL },
	.tosec   = { ALL_INIT_SECTIONS, NULL },
	.mismatch = DATA_TO_INIT,
},
{
	.fromsec = { TEXT_SECTIONS, NULL },
	.tosec   = { ALL_EXIT_SECTIONS, NULL },
	.mismatch = TEXT_TO_EXIT,
},
{
	.fromsec = { DATA_SECTIONS, NULL },
	.tosec   = { ALL_EXIT_SECTIONS, NULL },
	.mismatch = DATA_TO_EXIT,
845 846 847 848
},
/* Do not reference init code/data from devinit/cpuinit/meminit code/data */
{
	.fromsec = { DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, MEM_INIT_SECTIONS, NULL },
849 850
	.tosec   = { INIT_SECTIONS, NULL },
	.mismatch = XXXINIT_TO_INIT,
851 852 853 854
},
/* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
{
	.fromsec = { DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, MEM_EXIT_SECTIONS, NULL },
855 856
	.tosec   = { EXIT_SECTIONS, NULL },
	.mismatch = XXXEXIT_TO_EXIT,
857 858 859
},
/* Do not use exit code/data from init code */
{
860 861
	.fromsec = { ALL_INIT_SECTIONS, NULL },
	.tosec   = { ALL_EXIT_SECTIONS, NULL },
862
	.mismatch = INIT_TO_EXIT,
863 864 865
},
/* Do not use init code/data from exit code */
{
866
	.fromsec = { ALL_EXIT_SECTIONS, NULL },
867 868
	.tosec   = { ALL_INIT_SECTIONS, NULL },
	.mismatch = EXIT_TO_INIT,
869 870 871 872
},
/* Do not export init/exit functions or data */
{
	.fromsec = { "__ksymtab*", NULL },
873
	.tosec   = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
874
	.mismatch = EXPORT_TO_INIT_EXIT
875 876 877 878 879 880 881 882 883 884 885 886
}
};

static int section_mismatch(const char *fromsec, const char *tosec)
{
	int i;
	int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
	const struct sectioncheck *check = &sectioncheck[0];

	for (i = 0; i < elems; i++) {
		if (match(fromsec, check->fromsec) &&
		    match(tosec, check->tosec))
887
			return check->mismatch;
888 889
		check++;
	}
890
	return NO_MISMATCH;
891 892
}

893 894
/**
 * Whitelist to allow certain references to pass with no warning.
895 896 897 898
 *
 * Pattern 0:
 *   Do not warn if funtion/data are marked with __init_refok/__initdata_refok.
 *   The pattern is identified by:
899
 *   fromsec = .text.init.refok* | .data.init.refok*
900
 *
901 902 903 904 905 906 907
 * 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
908
 *   fromsec = .data*
909
 *   atsym   =__param*
910
 *
911
 * Pattern 2:
912
 *   Many drivers utilise a *driver container with references to
913 914 915 916
 *   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:
917 918
 *   tosec   = init or exit section
 *   fromsec = data section
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Sam Ravnborg 已提交
919 920
 *   atsym = *driver, *_template, *_sht, *_ops, *_probe,
 *           *probe_one, *_console, *_timer
921 922
 *
 * Pattern 3:
923 924 925
 *   Whitelist all refereces from .text.head to .init.data
 *   Whitelist all refereces from .text.head to .init.text
 *
926
 * Pattern 4:
927 928 929 930 931 932 933
 *   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
934
 *
935
 **/
936 937
static int secref_whitelist(const char *fromsec, const char *fromsym,
			    const char *tosec, const char *tosym)
938
{
939
	/* Check for pattern 0 */
940
	if (match(fromsec, initref_sections))
941
		return 0;
942

943
	/* Check for pattern 1 */
944 945
	if (match(tosec, init_data_sections) &&
	    match(fromsec, data_sections) &&
946 947
	    (strncmp(fromsym, "__param", strlen("__param")) == 0))
		return 0;
948 949

	/* Check for pattern 2 */
950 951
	if (match(tosec, init_exit_sections) &&
	    match(fromsec, data_sections) &&
952 953
	    match(fromsym, symbol_white_list))
		return 0;
954

955
	/* Check for pattern 3 */
956 957
	if (match(fromsec, head_sections) &&
	    match(tosec, init_sections))
958
		return 0;
959

960
	/* Check for pattern 4 */
961 962
	if (match(tosym, linker_symbols))
		return 0;
963

964
	return 1;
965 966
}

967 968 969 970 971 972 973
/**
 * 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.
 *  **/
974
static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
975 976 977
				Elf_Sym *relsym)
{
	Elf_Sym *sym;
978 979 980
	Elf_Sym *near = NULL;
	Elf64_Sword distance = 20;
	Elf64_Sword d;
981 982 983 984 985 986

	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;
987 988
		if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
			continue;
989 990
		if (sym->st_value == addr)
			return sym;
991 992 993 994 995 996 997 998
		/* Find a symbol nearby - addr are maybe negative */
		d = sym->st_value - addr;
		if (d < 0)
			d = addr - sym->st_value;
		if (d < distance) {
			distance = d;
			near = sym;
		}
999
	}
1000 1001 1002 1003 1004
	/* We need a close match */
	if (distance < 20)
		return near;
	else
		return NULL;
1005 1006
}

1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030
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);
}

1031
/*
1032 1033 1034 1035
 * 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.
1036
 **/
1037 1038
static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
				 const char *sec)
1039 1040
{
	Elf_Sym *sym;
1041 1042
	Elf_Sym *near = NULL;
	Elf_Addr distance = ~0;
1043

1044 1045 1046 1047 1048
	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
		const char *symsec;

		if (sym->st_shndx >= SHN_LORESERVE)
			continue;
1049
		symsec = sec_name(elf, sym->st_shndx);
1050 1051
		if (strcmp(symsec, sec) != 0)
			continue;
1052 1053
		if (!is_valid_name(elf, sym))
			continue;
1054
		if (sym->st_value <= addr) {
1055 1056 1057 1058 1059
			if ((addr - sym->st_value) < distance) {
				distance = addr - sym->st_value;
				near = sym;
			} else if ((addr - sym->st_value) == distance) {
				near = sym;
1060
			}
1061 1062
		}
	}
1063
	return near;
1064 1065
}

1066 1067 1068 1069 1070 1071 1072 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
/*
 * Convert a section name to the function/data attribute
 * .init.text => __init
 * .cpuinit.data => __cpudata
 * .memexitconst => __memconst
 * etc.
*/
static char *sec2annotation(const char *s)
{
	if (match(s, init_exit_sections)) {
		char *p = malloc(20);
		char *r = p;

		*p++ = '_';
		*p++ = '_';
		if (*s == '.')
			s++;
		while (*s && *s != '.')
			*p++ = *s++;
		*p = '\0';
		if (*s == '.')
			s++;
		if (strstr(s, "rodata") != NULL)
			strcat(p, "const ");
		else if (strstr(s, "data") != NULL)
			strcat(p, "data ");
		else
			strcat(p, " ");
		return r; /* we leak her but we do not care */
	} else {
		return "";
	}
}

static int is_function(Elf_Sym *sym)
{
	if (sym)
		return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
	else
1105
		return -1;
1106 1107
}

1108
/*
1109 1110
 * Print a warning about a section mismatch.
 * Try to find symbols near it so user can find it.
1111
 * Check whitelist before warning - it may be a false positive.
1112
 */
1113
static void report_sec_mismatch(const char *modname, enum mismatch mismatch,
1114 1115 1116
                                const char *fromsec,
                                unsigned long long fromaddr,
                                const char *fromsym,
1117 1118 1119 1120 1121 1122
                                int from_is_func,
                                const char *tosec, const char *tosym,
                                int to_is_func)
{
	const char *from, *from_p;
	const char *to, *to_p;
1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133

	switch (from_is_func) {
	case 0: from = "variable"; from_p = "";   break;
	case 1: from = "function"; from_p = "()"; break;
	default: from = "(unknown reference)"; from_p = ""; break;
	}
	switch (to_is_func) {
	case 0: to = "variable"; to_p = "";   break;
	case 1: to = "function"; to_p = "()"; break;
	default: to = "(unknown reference)"; to_p = ""; break;
	}
1134

1135 1136 1137 1138
	sec_mismatch_count++;
	if (!sec_mismatch_verbose)
		return;

1139 1140 1141 1142
	warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
	     "to the %s %s:%s%s\n",
	     modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
	     tosym, to_p);
1143 1144 1145 1146

	switch (mismatch) {
	case TEXT_TO_INIT:
		fprintf(stderr,
1147
		"The function %s%s() references\n"
1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167
		"the %s %s%s%s.\n"
		"This is often because %s lacks a %s\n"
		"annotation or the annotation of %s is wrong.\n",
		sec2annotation(fromsec), fromsym,
		to, sec2annotation(tosec), tosym, to_p,
		fromsym, sec2annotation(tosec), tosym);
		break;
	case DATA_TO_INIT: {
		const char **s = symbol_white_list;
		fprintf(stderr,
		"The variable %s references\n"
		"the %s %s%s%s\n"
		"If the reference is valid then annotate the\n"
		"variable with __init* (see linux/init.h) "
		"or name the variable:\n",
		fromsym, to, sec2annotation(tosec), tosym, to_p);
		while (*s)
			fprintf(stderr, "%s, ", *s++);
		fprintf(stderr, "\n");
		break;
1168
	}
1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237
	case TEXT_TO_EXIT:
		fprintf(stderr,
		"The function %s() references a %s in an exit section.\n"
		"Often the %s %s%s has valid usage outside the exit section\n"
		"and the fix is to remove the %sannotation of %s.\n",
		fromsym, to, to, tosym, to_p, sec2annotation(tosec), tosym);
		break;
	case DATA_TO_EXIT: {
		const char **s = symbol_white_list;
		fprintf(stderr,
		"The variable %s references\n"
		"the %s %s%s%s\n"
		"If the reference is valid then annotate the\n"
		"variable with __exit* (see linux/init.h) or "
		"name the variable:\n",
		fromsym, to, sec2annotation(tosec), tosym, to_p);
		while (*s)
			fprintf(stderr, "%s, ", *s++);
		fprintf(stderr, "\n");
		break;
	}
	case XXXINIT_TO_INIT:
	case XXXEXIT_TO_EXIT:
		fprintf(stderr,
		"The %s %s%s%s references\n"
		"a %s %s%s%s.\n"
		"If %s is only used by %s then\n"
		"annotate %s with a matching annotation.\n",
		from, sec2annotation(fromsec), fromsym, from_p,
		to, sec2annotation(tosec), tosym, to_p,
		fromsym, tosym, fromsym);
		break;
	case INIT_TO_EXIT:
		fprintf(stderr,
		"The %s %s%s%s references\n"
		"a %s %s%s%s.\n"
		"This is often seen when error handling "
		"in the init function\n"
		"uses functionality in the exit path.\n"
		"The fix is often to remove the %sannotation of\n"
		"%s%s so it may be used outside an exit section.\n",
		from, sec2annotation(fromsec), fromsym, from_p,
		to, sec2annotation(tosec), tosym, to_p,
		sec2annotation(tosec), tosym, to_p);
		break;
	case EXIT_TO_INIT:
		fprintf(stderr,
		"The %s %s%s%s references\n"
		"a %s %s%s%s.\n"
		"This is often seen when error handling "
		"in the exit function\n"
		"uses functionality in the init path.\n"
		"The fix is often to remove the %sannotation of\n"
		"%s%s so it may be used outside an init section.\n",
		from, sec2annotation(fromsec), fromsym, from_p,
		to, sec2annotation(tosec), tosym, to_p,
		sec2annotation(tosec), tosym, to_p);
		break;
	case EXPORT_TO_INIT_EXIT:
		fprintf(stderr,
		"The symbol %s is exported and annotated %s\n"
		"Fix this by removing the %sannotation of %s "
		"or drop the export.\n",
		tosym, sec2annotation(tosec), sec2annotation(tosec), tosym);
	case NO_MISMATCH:
		/* To get warnings on missing members */
		break;
	}
	fprintf(stderr, "\n");
1238 1239 1240 1241 1242 1243
}

static void check_section_mismatch(const char *modname, struct elf_info *elf,
                                   Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
{
	const char *tosec;
1244
	enum mismatch mismatch;
1245 1246

	tosec = sec_name(elf, sym->st_shndx);
1247 1248 1249 1250
	mismatch = section_mismatch(fromsec, tosec);
	if (mismatch != NO_MISMATCH) {
		Elf_Sym *to;
		Elf_Sym *from;
1251
		const char *tosym;
1252
		const char *fromsym;
1253

1254 1255 1256 1257
		from = find_elf_symbol2(elf, r->r_offset, fromsec);
		fromsym = sym_name(elf, from);
		to = find_elf_symbol(elf, r->r_addend, sym);
		tosym = sym_name(elf, to);
1258 1259 1260

		/* check whitelist - we may ignore it */
		if (secref_whitelist(fromsec, fromsym, tosec, tosym)) {
1261 1262 1263 1264
			report_sec_mismatch(modname, mismatch,
			   fromsec, r->r_offset, fromsym,
			   is_function(from), tosec, tosym,
			   is_function(to));
1265
		}
1266 1267 1268
	}
}

1269
static unsigned int *reloc_location(struct elf_info *elf,
1270
				    Elf_Shdr *sechdr, Elf_Rela *r)
1271 1272
{
	Elf_Shdr *sechdrs = elf->sechdrs;
1273
	int section = sechdr->sh_info;
1274 1275 1276 1277 1278

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

1279
static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1280 1281
{
	unsigned int r_typ = ELF_R_TYPE(r->r_info);
1282
	unsigned int *location = reloc_location(elf, sechdr, r);
1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297

	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;
}

1298
static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1299 1300 1301 1302 1303 1304
{
	unsigned int r_typ = ELF_R_TYPE(r->r_info);

	switch (r_typ) {
	case R_ARM_ABS32:
		/* From ARM ABI: (S + A) | T */
S
Sam Ravnborg 已提交
1305 1306
		r->r_addend = (int)(long)
		              (elf->symtab_start + ELF_R_SYM(r->r_info));
1307 1308 1309
		break;
	case R_ARM_PC24:
		/* From ARM ABI: ((S + A) | T) - P */
S
Sam Ravnborg 已提交
1310
		r->r_addend = (int)(long)(elf->hdr +
1311 1312
		              sechdr->sh_offset +
		              (r->r_offset - sechdr->sh_addr));
1313 1314 1315 1316 1317 1318 1319
		break;
	default:
		return 1;
	}
	return 0;
}

1320
static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1321 1322
{
	unsigned int r_typ = ELF_R_TYPE(r->r_info);
1323
	unsigned int *location = reloc_location(elf, sechdr, r);
1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342
	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;
}

1343
static void section_rela(const char *modname, struct elf_info *elf,
1344
                         Elf_Shdr *sechdr)
1345 1346 1347 1348 1349 1350 1351
{
	Elf_Sym  *sym;
	Elf_Rela *rela;
	Elf_Rela r;
	unsigned int r_sym;
	const char *fromsec;

1352
	Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1353 1354
	Elf_Rela *stop  = (void *)start + sechdr->sh_size;

1355
	fromsec = sech_name(elf, sechdr);
1356 1357
	fromsec += strlen(".rela");
	/* if from section (name) is know good then skip it */
1358
	if (check_section(modname, fromsec))
1359
		return;
1360

1361 1362 1363
	for (rela = start; rela < stop; rela++) {
		r.r_offset = TO_NATIVE(rela->r_offset);
#if KERNEL_ELFCLASS == ELFCLASS64
1364
		if (elf->hdr->e_machine == EM_MIPS) {
1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382
			unsigned int r_typ;
			r_sym = ELF64_MIPS_R_SYM(rela->r_info);
			r_sym = TO_NATIVE(r_sym);
			r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
			r.r_info = ELF64_R_INFO(r_sym, r_typ);
		} else {
			r.r_info = TO_NATIVE(rela->r_info);
			r_sym = ELF_R_SYM(r.r_info);
		}
#else
		r.r_info = TO_NATIVE(rela->r_info);
		r_sym = ELF_R_SYM(r.r_info);
#endif
		r.r_addend = TO_NATIVE(rela->r_addend);
		sym = elf->symtab_start + r_sym;
		/* Skip special sections */
		if (sym->st_shndx >= SHN_LORESERVE)
			continue;
1383
		check_section_mismatch(modname, elf, &r, sym, fromsec);
1384 1385 1386 1387
	}
}

static void section_rel(const char *modname, struct elf_info *elf,
1388
                        Elf_Shdr *sechdr)
1389 1390 1391 1392 1393 1394 1395
{
	Elf_Sym *sym;
	Elf_Rel *rel;
	Elf_Rela r;
	unsigned int r_sym;
	const char *fromsec;

1396
	Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1397 1398
	Elf_Rel *stop  = (void *)start + sechdr->sh_size;

1399
	fromsec = sech_name(elf, sechdr);
1400 1401
	fromsec += strlen(".rel");
	/* if from section (name) is know good then skip it */
1402
	if (check_section(modname, fromsec))
1403 1404 1405 1406 1407
		return;

	for (rel = start; rel < stop; rel++) {
		r.r_offset = TO_NATIVE(rel->r_offset);
#if KERNEL_ELFCLASS == ELFCLASS64
1408
		if (elf->hdr->e_machine == EM_MIPS) {
1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422
			unsigned int r_typ;
			r_sym = ELF64_MIPS_R_SYM(rel->r_info);
			r_sym = TO_NATIVE(r_sym);
			r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
			r.r_info = ELF64_R_INFO(r_sym, r_typ);
		} else {
			r.r_info = TO_NATIVE(rel->r_info);
			r_sym = ELF_R_SYM(r.r_info);
		}
#else
		r.r_info = TO_NATIVE(rel->r_info);
		r_sym = ELF_R_SYM(r.r_info);
#endif
		r.r_addend = 0;
1423
		switch (elf->hdr->e_machine) {
1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440
		case EM_386:
			if (addend_386_rel(elf, sechdr, &r))
				continue;
			break;
		case EM_ARM:
			if (addend_arm_rel(elf, sechdr, &r))
				continue;
			break;
		case EM_MIPS:
			if (addend_mips_rel(elf, sechdr, &r))
				continue;
			break;
		}
		sym = elf->symtab_start + r_sym;
		/* Skip special sections */
		if (sym->st_shndx >= SHN_LORESERVE)
			continue;
1441
		check_section_mismatch(modname, elf, &r, sym, fromsec);
1442 1443 1444
	}
}

1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457
/**
 * 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,
1458
                          struct elf_info *elf)
1459 1460 1461
{
	int i;
	Elf_Shdr *sechdrs = elf->sechdrs;
1462

1463
	/* Walk through all sections */
1464
	for (i = 0; i < elf->hdr->e_shnum; i++) {
1465
		/* We want to process only relocation sections and not .init */
1466
		if (sechdrs[i].sh_type == SHT_RELA)
1467
			section_rela(modname, elf, &elf->sechdrs[i]);
1468
		else if (sechdrs[i].sh_type == SHT_REL)
1469
			section_rel(modname, elf, &elf->sechdrs[i]);
1470 1471 1472
	}
}

1473
static void read_symbols(char *modname)
L
Linus Torvalds 已提交
1474 1475 1476
{
	const char *symname;
	char *version;
1477
	char *license;
L
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1478 1479 1480 1481
	struct module *mod;
	struct elf_info info = { };
	Elf_Sym *sym;

1482 1483
	if (!parse_elf(&info, modname))
		return;
L
Linus Torvalds 已提交
1484 1485 1486 1487 1488 1489 1490 1491 1492 1493

	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;
	}

1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505
	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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1506 1507 1508 1509 1510 1511
	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);
	}
1512
	if (!is_vmlinux(modname) ||
1513 1514
	     (is_vmlinux(modname) && vmlinux_section_warnings))
		check_sec_ref(mod, modname, &info);
L
Linus Torvalds 已提交
1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539

	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 */

1540 1541
void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
						      const char *fmt, ...)
L
Linus Torvalds 已提交
1542 1543 1544 1545
{
	char tmp[SZ];
	int len;
	va_list ap;
1546

L
Linus Torvalds 已提交
1547 1548
	va_start(ap, fmt);
	len = vsnprintf(tmp, SZ, fmt, ap);
1549
	buf_write(buf, tmp, len);
L
Linus Torvalds 已提交
1550 1551 1552
	va_end(ap);
}

1553
void buf_write(struct buffer *buf, const char *s, int len)
L
Linus Torvalds 已提交
1554 1555
{
	if (buf->size - buf->pos < len) {
1556
		buf->size += len + SZ;
L
Linus Torvalds 已提交
1557 1558 1559 1560 1561 1562
		buf->p = realloc(buf->p, buf->size);
	}
	strncpy(buf->p + buf->pos, s, len);
	buf->pos += len;
}

1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587
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;
	}
}

S
Sam Ravnborg 已提交
1588
static void check_for_unused(enum export exp, const char *m, const char *s)
1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604
{
	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)
1605 1606 1607 1608
{
	struct symbol *s, *exp;

	for (s = mod->unres; s; s = s->next) {
A
Andrew Morton 已提交
1609
		const char *basename;
1610 1611 1612
		exp = find_symbol(s->name);
		if (!exp || exp->module == mod)
			continue;
A
Andrew Morton 已提交
1613
		basename = strrchr(mod->name, '/');
1614 1615
		if (basename)
			basename++;
1616 1617 1618 1619 1620
		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);
S
Sam Ravnborg 已提交
1621
	}
1622 1623
}

1624 1625 1626 1627
/**
 * Header for the generated file
 **/
static void add_header(struct buffer *b, struct module *mod)
L
Linus Torvalds 已提交
1628 1629 1630 1631 1632 1633 1634 1635 1636
{
	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");
1637
	buf_printf(b, " .name = KBUILD_MODNAME,\n");
L
Linus Torvalds 已提交
1638 1639 1640 1641 1642 1643
	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");
1644
	buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
L
Linus Torvalds 已提交
1645 1646 1647
	buf_printf(b, "};\n");
}

1648 1649 1650
/**
 * Record CRCs for unresolved symbols
 **/
1651
static int add_versions(struct buffer *b, struct module *mod)
L
Linus Torvalds 已提交
1652 1653
{
	struct symbol *s, *exp;
1654
	int err = 0;
L
Linus Torvalds 已提交
1655 1656 1657 1658

	for (s = mod->unres; s; s = s->next) {
		exp = find_symbol(s->name);
		if (!exp || exp->module == mod) {
1659
			if (have_vmlinux && !s->weak) {
1660 1661 1662 1663 1664 1665 1666 1667
				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;
				}
1668
			}
L
Linus Torvalds 已提交
1669 1670 1671 1672 1673 1674 1675 1676
			continue;
		}
		s->module = exp->module;
		s->crc_valid = exp->crc_valid;
		s->crc = exp->crc;
	}

	if (!modversions)
1677
		return err;
L
Linus Torvalds 已提交
1678 1679 1680

	buf_printf(b, "\n");
	buf_printf(b, "static const struct modversion_info ____versions[]\n");
A
Adrian Bunk 已提交
1681
	buf_printf(b, "__used\n");
L
Linus Torvalds 已提交
1682 1683 1684
	buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");

	for (s = mod->unres; s; s = s->next) {
S
Sam Ravnborg 已提交
1685
		if (!s->module)
L
Linus Torvalds 已提交
1686 1687
			continue;
		if (!s->crc_valid) {
1688
			warn("\"%s\" [%s.ko] has no CRC!\n",
L
Linus Torvalds 已提交
1689 1690 1691 1692 1693 1694 1695
				s->name, mod->name);
			continue;
		}
		buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
	}

	buf_printf(b, "};\n");
1696 1697

	return err;
L
Linus Torvalds 已提交
1698 1699
}

1700 1701
static void add_depends(struct buffer *b, struct module *mod,
			struct module *modules)
L
Linus Torvalds 已提交
1702 1703 1704 1705 1706
{
	struct symbol *s;
	struct module *m;
	int first = 1;

S
Sam Ravnborg 已提交
1707
	for (m = modules; m; m = m->next)
L
Linus Torvalds 已提交
1708 1709 1710 1711
		m->seen = is_vmlinux(m->name);

	buf_printf(b, "\n");
	buf_printf(b, "static const char __module_depends[]\n");
A
Adrian Bunk 已提交
1712
	buf_printf(b, "__used\n");
L
Linus Torvalds 已提交
1713 1714 1715
	buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
	buf_printf(b, "\"depends=");
	for (s = mod->unres; s; s = s->next) {
1716
		const char *p;
L
Linus Torvalds 已提交
1717 1718 1719 1720 1721 1722 1723
		if (!s->module)
			continue;

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

		s->module->seen = 1;
S
Sam Ravnborg 已提交
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		p = strrchr(s->module->name, '/');
		if (p)
1726 1727 1728 1729
			p++;
		else
			p = s->module->name;
		buf_printf(b, "%s%s", first ? "" : ",", p);
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		first = 0;
	}
	buf_printf(b, "\";\n");
}

1735
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);
	}
}

1744
static void write_if_changed(struct buffer *b, const char *fname)
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1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787
{
	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);
}

1788
/* parse Module.symvers file. line format:
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 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1790
 **/
1791
static void read_dump(const char *fname, unsigned int kernel)
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{
	unsigned long size, pos = 0;
	void *file = grab_file(fname, &size);
	char *line;

S
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1797
	if (!file)
L
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		/* No symbol versions, silently ignore */
		return;

	while ((line = get_next_line(&pos, file, size))) {
S
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1802
		char *symname, *modname, *d, *export, *end;
L
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1803 1804
		unsigned int crc;
		struct module *mod;
1805
		struct symbol *s;
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		if (!(symname = strchr(line, '\t')))
			goto fail;
		*symname++ = '\0';
		if (!(modname = strchr(symname, '\t')))
			goto fail;
		*modname++ = '\0';
1813
		if ((export = strchr(modname, '\t')) != NULL)
1814
			*export++ = '\0';
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1815 1816
		if (export && ((end = strchr(export, '\t')) != NULL))
			*end = '\0';
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		crc = strtoul(line, &d, 16);
		if (*symname == '\0' || *modname == '\0' || *d != '\0')
			goto fail;
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		mod = find_module(modname);
		if (!mod) {
			if (is_vmlinux(modname))
L
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				have_vmlinux = 1;
			mod = new_module(NOFAIL(strdup(modname)));
			mod->skip = 1;
		}
1827
		s = sym_add_exported(symname, mod, export_no(export));
1828 1829
		s->kernel    = kernel;
		s->preloaded = 1;
1830
		sym_update_crc(symname, mod, crc, export_no(export));
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	}
	return;
fail:
	fatal("parse error in symbol dump file\n");
}

1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848
/* 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;
}
1849

1850
static void write_dump(const char *fname)
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1851 1852 1853 1854 1855 1856 1857 1858
{
	struct buffer buf = { };
	struct symbol *symbol;
	int n;

	for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
		symbol = symbolhash[n];
		while (symbol) {
1859
			if (dump_sym(symbol))
1860
				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1861
					symbol->crc, symbol->name,
1862 1863
					symbol->module->name,
					export_str(symbol->export));
L
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1864 1865 1866 1867 1868 1869
			symbol = symbol->next;
		}
	}
	write_if_changed(&buf, fname);
}

1870
int main(int argc, char **argv)
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Linus Torvalds 已提交
1871 1872 1873
{
	struct module *mod;
	struct buffer buf = { };
1874 1875
	char *kernel_read = NULL, *module_read = NULL;
	char *dump_write = NULL;
L
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1876
	int opt;
1877
	int err;
L
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1878

1879
	while ((opt = getopt(argc, argv, "i:I:msSo:aw")) != -1) {
S
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1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899
		switch (opt) {
		case 'i':
			kernel_read = optarg;
			break;
		case 'I':
			module_read = optarg;
			external_module = 1;
			break;
		case 'm':
			modversions = 1;
			break;
		case 'o':
			dump_write = optarg;
			break;
		case 'a':
			all_versions = 1;
			break;
		case 's':
			vmlinux_section_warnings = 0;
			break;
1900 1901 1902
		case 'S':
			sec_mismatch_verbose = 0;
			break;
S
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1903 1904 1905 1906 1907
		case 'w':
			warn_unresolved = 1;
			break;
		default:
			exit(1);
L
Linus Torvalds 已提交
1908 1909 1910
		}
	}

1911 1912 1913 1914
	if (kernel_read)
		read_dump(kernel_read, 1);
	if (module_read)
		read_dump(module_read, 0);
L
Linus Torvalds 已提交
1915

S
Sam Ravnborg 已提交
1916
	while (optind < argc)
L
Linus Torvalds 已提交
1917 1918
		read_symbols(argv[optind++]);

1919 1920 1921
	for (mod = modules; mod; mod = mod->next) {
		if (mod->skip)
			continue;
1922
		check_exports(mod);
1923 1924
	}

1925 1926
	err = 0;

L
Linus Torvalds 已提交
1927
	for (mod = modules; mod; mod = mod->next) {
1928 1929
		char fname[strlen(mod->name) + 10];

L
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1930 1931 1932 1933 1934 1935
		if (mod->skip)
			continue;

		buf.pos = 0;

		add_header(&buf, mod);
1936
		err |= add_versions(&buf, mod);
L
Linus Torvalds 已提交
1937 1938 1939 1940 1941 1942 1943 1944 1945 1946
		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);
1947
	if (sec_mismatch_count && !sec_mismatch_verbose)
1948 1949 1950 1951
		warn("modpost: Found %d section mismatch(es).\n"
		     "To see full details build your kernel with:\n"
		     "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
		     sec_mismatch_count);
L
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1952

1953
	return err;
L
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1954
}