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modpost: stop symbol preloading for modversion CRC

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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: Masahiro Yamada <yamada.masahiro@socionext.com>
This commit is contained in:
Masahiro Yamada 2019-11-15 02:42:24 +09:00
parent 9bd2a099d7
commit 1743694eb2
1 changed files with 39 additions and 32 deletions
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71
scripts/mod/modpost.c
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@ -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;
}
@ -683,12 +684,34 @@ static int ignore_undef_symbol(struct elf_info *info, const char *symname)
return 0;
}
static void handle_modversion(const struct module *mod,
const struct elf_info *info,
const Elf_Sym *sym, const char *symname)
{
unsigned int crc;
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;
}
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_set_crc(symname, crc);
}
static void handle_symbol(struct module *mod, 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) &&
@ -697,21 +720,6 @@ static void handle_symbol(struct module *mod, struct elf_info *info,
else
export = export_from_sec(info, get_secindex(info, sym));
/* 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) {
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);
}
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);