kbuild: improved modversioning support for external modules
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>
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 4a2f2e3..976adf1 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -20,6 +20,8 @@
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 @@
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 @@
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 @@
}
/* 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 @@
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 @@
* 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 @@
/* 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 @@
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 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 @@
/* 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 @@
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 @@
char *symname, *modname, *d;
unsigned int crc;
struct module *mod;
+ struct symbol *s;
if (!(symname = strchr(line, '\t')))
goto fail;
@@ -699,13 +705,28 @@
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 @@
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 @@
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 @@
}
}
- 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++]);