[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);