[PATCH] add EXPORT_SYMBOL_GPL_FUTURE()

This patch adds the ability to mark symbols that will be changed in the
future, so that kernel modules that don't include MODULE_LICENSE("GPL")
and use the symbols, will be flagged and printed out to the system log.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 47 insertions, 2 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 2a892b20d68f..5ca99fbe9f44 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -126,8 +126,11 @@ extern const struct kernel_symbol __start___ksymtab[];
 extern const struct kernel_symbol __stop___ksymtab[];
 extern const struct kernel_symbol __start___ksymtab_gpl[];
 extern const struct kernel_symbol __stop___ksymtab_gpl[];
+extern const struct kernel_symbol __start___ksymtab_gpl_future[];
+extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
 extern const unsigned long __start___kcrctab[];
 extern const unsigned long __start___kcrctab_gpl[];
+extern const unsigned long __start___kcrctab_gpl_future[];
 
 #ifndef CONFIG_MODVERSIONS
 #define symversion(base, idx) NULL
@@ -172,6 +175,22 @@ static unsigned long __find_symbol(const char *name,
                         return ks->value;
                 }
         }
+        ks = lookup_symbol(name, __start___ksymtab_gpl_future,
+                                 __stop___ksymtab_gpl_future);
+        if (ks) {
+                if (!gplok) {
+                        printk(KERN_WARNING "Symbol %s is being used "
+                               "by a non-GPL module, which will not "
+                               "be allowed in the future\n", name);
+                        printk(KERN_WARNING "Please see the file "
+                               "Documentation/feature-removal-schedule.txt "
+                               "in the kernel source tree for more "
+                               "details.\n");
+                }
+                *crc = symversion(__start___kcrctab_gpl_future,
+                                  (ks - __start___ksymtab_gpl_future));
+                return ks->value;
+        }
 
         /* Now try modules. */ 
         list_for_each_entry(mod, &modules, list) {
@@ -191,6 +210,23 @@ static unsigned long __find_symbol(const char *name,
                                 return ks->value;
                         }
                 }
+                ks = lookup_symbol(name, mod->gpl_future_syms,
+                                   (mod->gpl_future_syms +
+                                    mod->num_gpl_future_syms));
+                if (ks) {
+                        if (!gplok) {
+                                printk(KERN_WARNING "Symbol %s is being used "
+                                       "by a non-GPL module, which will not "
+                                       "be allowed in the future\n", name);
+                                printk(KERN_WARNING "Please see the file "
+                                       "Documentation/feature-removal-schedule.txt "
+                                       "in the kernel source tree for more "
+                                       "details.\n");
+                        }
+                        *crc = symversion(mod->gpl_future_crcs,
+                                          (ks - mod->gpl_future_syms));
+                        return ks->value;
+                }
         }
         DEBUGP("Failed to find symbol %s\n", name);
         return 0;
@@ -1546,7 +1582,8 @@ static struct module *load_module(void __user *umod,
         char *secstrings, *args, *modmagic, *strtab = NULL;
         unsigned int i, symindex = 0, strindex = 0, setupindex, exindex,
                 exportindex, modindex, obsparmindex, infoindex, gplindex,
-                crcindex, gplcrcindex, versindex, pcpuindex;
+                crcindex, gplcrcindex, versindex, pcpuindex, gplfutureindex,
+                gplfuturecrcindex;
         long arglen;
         struct module *mod;
         long err = 0;
@@ -1627,8 +1664,10 @@ static struct module *load_module(void __user *umod,
         /* Optional sections */
         exportindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab");
         gplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl");
+        gplfutureindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl_future");
         crcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab");
         gplcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl");
+        gplfuturecrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl_future");
         setupindex = find_sec(hdr, sechdrs, secstrings, "__param");
         exindex = find_sec(hdr, sechdrs, secstrings, "__ex_table");
         obsparmindex = find_sec(hdr, sechdrs, secstrings, "__obsparm");
@@ -1784,10 +1823,16 @@ static struct module *load_module(void __user *umod,
         mod->gpl_syms = (void *)sechdrs[gplindex].sh_addr;
         if (gplcrcindex)
                 mod->gpl_crcs = (void *)sechdrs[gplcrcindex].sh_addr;
+        mod->num_gpl_future_syms = sechdrs[gplfutureindex].sh_size /
+                                        sizeof(*mod->gpl_future_syms);
+        mod->gpl_future_syms = (void *)sechdrs[gplfutureindex].sh_addr;
+        if (gplfuturecrcindex)
+                mod->gpl_future_crcs = (void *)sechdrs[gplfuturecrcindex].sh_addr;
 
 #ifdef CONFIG_MODVERSIONS
         if ((mod->num_syms && !crcindex) || 
-            (mod->num_gpl_syms && !gplcrcindex)) {
+            (mod->num_gpl_syms && !gplcrcindex) ||
+            (mod->num_gpl_future_syms && !gplfuturecrcindex)) {
                 printk(KERN_WARNING "%s: No versions for exported symbols."
                        " Tainting kernel.\n", mod->name);
                 add_taint(TAINT_FORCED_MODULE);