4 files changed, 85 insertions, 12 deletions

diff --git a/include/linux/license.h b/include/linux/license.h
new file mode 100644
index 000000000000..decdbf43cb5c
--- /dev/null
+++ b/include/linux/license.h
@@ -0,0 +1,14 @@
+#ifndef __LICENSE_H
+#define __LICENSE_H
+
+static inline int license_is_gpl_compatible(const char *license)
+{
+        return (strcmp(license, "GPL") == 0
+                || strcmp(license, "GPL v2") == 0
+                || strcmp(license, "GPL and additional rights") == 0
+                || strcmp(license, "Dual BSD/GPL") == 0
+                || strcmp(license, "Dual MIT/GPL") == 0
+                || strcmp(license, "Dual MPL/GPL") == 0);
+}
+
+#endif
diff --git a/kernel/module.c b/kernel/module.c
index bbe04862e1b0..690381508d09 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -43,6 +43,7 @@
 #include <asm/uaccess.h>
 #include <asm/semaphore.h>
 #include <asm/cacheflush.h>
+#include <linux/license.h>
 
 #if 0
 #define DEBUGP printk
@@ -1248,16 +1249,6 @@ static void layout_sections(struct module *mod,
         }
 }
 
-static inline int license_is_gpl_compatible(const char *license)
-{
-        return (strcmp(license, "GPL") == 0
-                || strcmp(license, "GPL v2") == 0
-                || strcmp(license, "GPL and additional rights") == 0
-                || strcmp(license, "Dual BSD/GPL") == 0
-                || strcmp(license, "Dual MIT/GPL") == 0
-                || strcmp(license, "Dual MPL/GPL") == 0);
-}
-
 static void set_license(struct module *mod, const char *license)
 {
         if (!license)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index ba2e4fc2af20..baa4d83d29a8 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -13,6 +13,7 @@
 
 #include <ctype.h>
 #include "modpost.h"
+#include "../../include/linux/license.h"
 
 /* Are we using CONFIG_MODVERSIONS? */
 int modversions = 0;
@@ -99,6 +100,7 @@ static struct module *new_module(char *modname)
 
         /* add to list */
         mod->name = p;
+        mod->gpl_compatible = -1;
         mod->next = modules;
         modules = mod;
 
@@ -493,13 +495,18 @@ static char *next_string(char *string, unsigned long *secsize)
         return string;
 }
 
-static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
-                         const char *tag)
+static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
+                              const char *tag, char *info)
 {
         char *p;
         unsigned int taglen = strlen(tag);
         unsigned long size = modinfo_len;
 
+        if (info) {
+                size -= info - (char *)modinfo;
+                modinfo = next_string(info, &size);
+        }
+
         for (p = modinfo; p; p = next_string(p, &size)) {
                 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
                         return p + taglen + 1;
@@ -507,6 +514,13 @@ static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
         return NULL;
 }
 
+static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
+                         const char *tag)
+
+{
+        return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
+}
+
 /**
  * Test if string s ends in string sub
  * return 0 if match
@@ -981,6 +995,7 @@ static void read_symbols(char *modname)
 {
         const char *symname;
         char *version;
+        char *license;
         struct module *mod;
         struct elf_info info = { };
         Elf_Sym *sym;
@@ -996,6 +1011,18 @@ static void read_symbols(char *modname)
                 mod->skip = 1;
         }
 
+        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);
+        }
+
         for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
                 symname = info.strtab + sym->st_name;
 
@@ -1052,6 +1079,40 @@ void buf_write(struct buffer *buf, const char *s, int len)
         buf->pos += len;
 }
 
+void check_license(struct module *mod)
+{
+        struct symbol *s, *exp;
+
+        for (s = mod->unres; s; s = s->next) {
+                if (mod->gpl_compatible == 1) {
+                        /* GPL-compatible modules may use all symbols */
+                        continue;
+                }
+                exp = find_symbol(s->name);
+                if (!exp || exp->module == mod)
+                        continue;
+                const char *basename = strrchr(mod->name, '/');
+                if (basename)
+                        basename++;
+                switch (exp->export) {
+                        case export_gpl:
+                                fatal("modpost: GPL-incompatible module %s "
+                                      "uses GPL-only symbol '%s'\n",
+                                 basename ? basename : mod->name,
+                                exp->name);
+                                break;
+                        case export_gpl_future:
+                                warn("modpost: GPL-incompatible module %s "
+                                      "uses future GPL-only symbol '%s'\n",
+                                      basename ? basename : mod->name,
+                                      exp->name);
+                                break;
+                        case export_plain: /* ignore */ break;
+                        case export_unknown: /* ignore */ break;
+                }
+        }
+}
+
 /**
  * Header for the generated file
  **/
@@ -1328,6 +1389,12 @@ int main(int argc, char **argv)
         for (mod = modules; mod; mod = mod->next) {
                 if (mod->skip)
                         continue;
+                check_license(mod);
+        }
+
+        for (mod = modules; mod; mod = mod->next) {
+                if (mod->skip)
+                        continue;
 
                 buf.pos = 0;
 
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index f7ee3a3fde14..2b00c6062844 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -100,6 +100,7 @@ buf_write(struct buffer *buf, const char *s, int len);
 struct module {
         struct module *next;
         const char *name;
+        int gpl_compatible;
         struct symbol *unres;
         int seen;
         int skip;