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kbuild: improved modversioning support for external modules

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With following patch a second option is enabled to obtain
symbol information from a second external module when a
external module is build.
The recommended approach is to use a common kbuild file but
that may be impractical in certain cases.
With this patch one can copy over a Module.symvers from one
external module to make symbols (and symbol versions) available
for another external module.

Updated documentation in Documentation/kbuild/modules.txt

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
This commit is contained in:
Sam Ravnborg
2006-01-28 22:15:55 +01:00
parent 5c3ead8c72
commit 040fcc819a
3 changed files with 158 additions and 59 deletions
Download Patch File Download Diff File Expand all files Collapse all files

123
scripts/mod/modpost.c
View File

@ -20,6 +20,8 @@ int modversions = 0;
int have_vmlinux = 0;
/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
static int all_versions = 0;
/* If we are modposting external module set to 1 */
static int external_module = 0;
void fatal(const char *fmt, ...)
{
@ -45,6 +47,18 @@ void warn(const char *fmt, ...)
va_end(arglist);
}
static int is_vmlinux(const char *modname)
{
const char *myname;
if ((myname = strrchr(modname, '/')))
myname++;
else
myname = modname;
return strcmp(myname, "vmlinux") == 0;
}
void *do_nofail(void *ptr, const char *expr)
{
if (!ptr) {
@ -100,6 +114,9 @@ struct symbol {
unsigned int crc;
int crc_valid;
unsigned int weak:1;
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) **/
char name[0];
};
@ -135,8 +152,7 @@ static struct symbol *alloc_symbol(const char *name, unsigned int weak,
}
/* For the hash of exported symbols */
static void new_symbol(const char *name, struct module *module,
unsigned int *crc)
static struct symbol *new_symbol(const char *name, struct module *module)
{
unsigned int hash;
struct symbol *new;
@ -144,10 +160,7 @@ static void new_symbol(const char *name, struct module *module,
hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
new->module = module;
if (crc) {
new->crc = *crc;
new->crc_valid = 1;
}
return new;
}
static struct symbol *find_symbol(const char *name)
@ -169,19 +182,27 @@ static struct symbol *find_symbol(const char *name)
* Add an exported symbol - it may have already been added without a
* CRC, in this case just update the CRC
**/
static void add_exported_symbol(const char *name, struct module *module,
unsigned int *crc)
static struct symbol *sym_add_exported(const char *name, struct module *mod)
{
struct symbol *s = find_symbol(name);
if (!s) {
new_symbol(name, module, crc);
return;
}
if (crc) {
s->crc = *crc;
s->crc_valid = 1;
}
if (!s)
s = new_symbol(name, mod);
s->vmlinux = is_vmlinux(mod->name);
s->kernel = 0;
return s;
}
static void sym_update_crc(const char *name, struct module *mod,
unsigned int crc)
{
struct symbol *s = find_symbol(name);
if (!s)
s = new_symbol(name, mod);
s->crc = crc;
s->crc_valid = 1;
}
void *grab_file(const char *filename, unsigned long *size)
@ -332,8 +353,7 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
/* CRC'd symbol */
if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
crc = (unsigned int) sym->st_value;
add_exported_symbol(symname + strlen(CRC_PFX),
mod, &crc);
sym_update_crc(symname + strlen(CRC_PFX), mod, crc);
}
break;
case SHN_UNDEF:
@ -377,8 +397,7 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
default:
/* All exported symbols */
if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
add_exported_symbol(symname + strlen(KSYMTAB_PFX),
mod, NULL);
sym_add_exported(symname + strlen(KSYMTAB_PFX), mod);
}
if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
mod->has_init = 1;
@ -388,18 +407,6 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
}
}
static int is_vmlinux(const char *modname)
{
const char *myname;
if ((myname = strrchr(modname, '/')))
myname++;
else
myname = modname;
return strcmp(myname, "vmlinux") == 0;
}
/**
* Parse tag=value strings from .modinfo section
**/
@ -450,9 +457,7 @@ static void read_symbols(char *modname)
/* When there's no vmlinux, don't print warnings about
* unresolved symbols (since there'll be too many ;) */
if (is_vmlinux(modname)) {
unsigned int fake_crc = 0;
have_vmlinux = 1;
add_exported_symbol("struct_module", mod, &fake_crc);
mod->skip = 1;
}
@ -665,7 +670,7 @@ static void write_if_changed(struct buffer *b, const char *fname)
fclose(file);
}
static void read_dump(const char *fname)
static void read_dump(const char *fname, unsigned int kernel)
{
unsigned long size, pos = 0;
void *file = grab_file(fname, &size);
@ -679,6 +684,7 @@ static void read_dump(const char *fname)
char *symname, *modname, *d;
unsigned int crc;
struct module *mod;
struct symbol *s;
if (!(symname = strchr(line, '\t')))
goto fail;
@ -699,13 +705,28 @@ static void read_dump(const char *fname)
mod = new_module(NOFAIL(strdup(modname)));
mod->skip = 1;
}
add_exported_symbol(symname, mod, &crc);
s = sym_add_exported(symname, mod);
s->kernel = kernel;
sym_update_crc(symname, mod, crc);
}
return;
fail:
fatal("parse error in symbol dump file\n");
}
/* 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;
}
static void write_dump(const char *fname)
{
struct buffer buf = { };
@ -715,15 +736,10 @@ static void write_dump(const char *fname)
for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
symbol = symbolhash[n];
while (symbol) {
symbol = symbol->next;
}
}
for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
symbol = symbolhash[n];
while (symbol) {
buf_printf(&buf, "0x%08x\t%s\t%s\n", symbol->crc,
symbol->name, symbol->module->name);
if (dump_sym(symbol))
buf_printf(&buf, "0x%08x\t%s\t%s\n",
symbol->crc, symbol->name,
symbol->module->name);
symbol = symbol->next;
}
}
@ -735,13 +751,18 @@ int main(int argc, char **argv)
struct module *mod;
struct buffer buf = { };
char fname[SZ];
char *dump_read = NULL, *dump_write = NULL;
char *kernel_read = NULL, *module_read = NULL;
char *dump_write = NULL;
int opt;
while ((opt = getopt(argc, argv, "i:mo:a")) != -1) {
while ((opt = getopt(argc, argv, "i:I:mo:a")) != -1) {
switch(opt) {
case 'i':
dump_read = optarg;
kernel_read = optarg;
break;
case 'I':
module_read = optarg;
external_module = 1;
break;
case 'm':
modversions = 1;
@ -757,8 +778,10 @@ int main(int argc, char **argv)
}
}
if (dump_read)
read_dump(dump_read);
if (kernel_read)
read_dump(kernel_read, 1);
if (module_read)
read_dump(module_read, 0);
while (optind < argc) {
read_symbols(argv[optind++]);