Commit 1743694e authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

modpost: stop symbol preloading for modversion CRC 



It is complicated to add mocked-up symbols for pre-handling CRC.
Handle CRC after all the export symbols in the relevant module
are registered.

Call handle_modversion() after the handle_symbol() iteration.

In some cases, I see atand-alone __crc_* without __ksymtab_*.
For example, ARCH=arm allyesconfig produces __crc_ccitt_veneer and
__crc_itu_t_veneer. I guess they come from crc_ccitt, crc_itu_t,
respectively. Since __*_veneer are auto-generated symbols, just
ignore them.

Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
parent 9bd2a099

scripts/mod/modpost.c

+39 −32
Original line number Diff line number Diff line
@@ -169,7 +169,7 @@ struct symbol { 
	unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */

	unsigned int kernel:1;     /* 1 if symbol is from kernel

				    *  (only for external modules) **/

	unsigned int preloaded:1;  /* 1 if symbol from Module.symvers, or crc */

	unsigned int preloaded:1;  /* 1 if symbol from Module.symvers */

	unsigned int is_static:1;  /* 1 if symbol is not global */

	enum export  export;       /* Type of export */

	char name[0];
@@ -410,16 +410,17 @@ static struct symbol *sym_add_exported(const char *name, struct module *mod, 
	return s;

}



static void sym_update_crc(const char *name, struct module *mod,

			   unsigned int crc, enum export export)

static void sym_set_crc(const char *name, unsigned int crc)

{

	struct symbol *s = find_symbol(name);



	if (!s) {

		s = new_symbol(name, mod, export);

		/* Don't complain when we find it later. */

		s->preloaded = 1;

	}

	/*

	 * Ignore stand-alone __crc_*, which might be auto-generated symbols

	 * such as __*_veneer in ARM ELF.

	 */

	if (!s)

		return;



	s->crc = crc;

	s->crc_valid = 1;

}
@@ -683,35 +684,42 @@ static int ignore_undef_symbol(struct elf_info *info, const char *symname) 
	return 0;

}



static void handle_symbol(struct module *mod, struct elf_info *info,

static void handle_modversion(const struct module *mod,

			      const struct elf_info *info,

			      const Elf_Sym *sym, const char *symname)

{

	unsigned int crc;

	enum export export;

	bool is_crc = false;

	const char *name;



	if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&

	    strstarts(symname, "__ksymtab"))

		export = export_from_secname(info, get_secindex(info, sym));

	else

		export = export_from_sec(info, get_secindex(info, sym));

	if (sym->st_shndx == SHN_UNDEF) {

		warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",

		     symname, mod->name, is_vmlinux(mod->name) ? "":".ko");

		return;

	}



	/* CRC'd symbol */

	if (strstarts(symname, "__crc_")) {

		is_crc = true;

		crc = (unsigned int) sym->st_value;

		if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {

	if (sym->st_shndx == SHN_ABS) {

		crc = sym->st_value;

	} else {

		unsigned int *crcp;



		/* symbol points to the CRC in the ELF object */

		crcp = sym_get_data(info, sym);

		crc = TO_NATIVE(*crcp);

	}

		sym_update_crc(symname + strlen("__crc_"), mod, crc,

				export);

	sym_set_crc(symname, crc);

}



static void handle_symbol(struct module *mod, struct elf_info *info,

			  const Elf_Sym *sym, const char *symname)

{

	enum export export;

	const char *name;



	if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&

	    strstarts(symname, "__ksymtab"))

		export = export_from_secname(info, get_secindex(info, sym));

	else

		export = export_from_sec(info, get_secindex(info, sym));



	switch (sym->st_shndx) {

	case SHN_COMMON:

		if (strstarts(symname, "__gnu_lto_")) {
@@ -746,11 +754,6 @@ static void handle_symbol(struct module *mod, struct elf_info *info, 
		}

#endif



		if (is_crc) {

			const char *e = is_vmlinux(mod->name) ?"":".ko";

			warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",

			     symname + strlen("__crc_"), mod->name, e);

		}

		mod->unres = alloc_symbol(symname,

					  ELF_ST_BIND(sym->st_info) == STB_WEAK,

					  mod->unres);
@@ -2055,14 +2058,18 @@ static void read_symbols(const char *modname) 
		handle_moddevtable(mod, &info, sym, symname);

	}



	/* Apply symbol namespaces from __kstrtabns_<symbol> entries. */

	for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {

		symname = remove_dot(info.strtab + sym->st_name);



		/* Apply symbol namespaces from __kstrtabns_<symbol> entries. */

		if (strstarts(symname, "__kstrtabns_"))

			sym_update_namespace(symname + strlen("__kstrtabns_"),

					     namespace_from_kstrtabns(&info,

								      sym));



		if (strstarts(symname, "__crc_"))

			handle_modversion(mod, &info, sym,

					  symname + strlen("__crc_"));

	}



	// check for static EXPORT_SYMBOL_* functions && global vars
@@ -2476,7 +2483,7 @@ static void read_dump(const char *fname, unsigned int kernel) 
		s->kernel    = kernel;

		s->preloaded = 1;

		s->is_static = 0;

		sym_update_crc(symname, mod, crc, export_no(export));

		sym_set_crc(symname, crc);

		sym_update_namespace(symname, namespace);

	}

	release_file(file, size);

CRA Git | Maintained and supported by SUSTech CRA and CCSE