[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>

arch/m68knommu/kernel/vmlinux.lds.S

@@ -269,6 +269,11 @@ SECTIONS {
 		*(__ksymtab_gpl)
 		__stop___ksymtab_gpl = .;
 
+		/* Kernel symbol table: GPL-future symbols */
+		__start___ksymtab_gpl_future = .;
+		*(__ksymtab_gpl_future)
+		__stop___ksymtab_gpl_future = .;
+
 		/* Kernel symbol table: Normal symbols */
 		__start___kcrctab = .;
 		*(__kcrctab)
@@ -279,6 +284,11 @@ SECTIONS {
 		*(__kcrctab_gpl)
 		__stop___kcrctab_gpl = .;
 
+		/* Kernel symbol table: GPL-future symbols */
+		__start___kcrctab_gpl_future = .;
+		*(__kcrctab_gpl_future)
+		__stop___kcrctab_gpl_future = .;
+
 		/* Kernel symbol table: strings */
 		*(__ksymtab_strings)
 

arch/v850/kernel/vmlinux.lds.S

@@ -64,6 +64,10 @@
 		___start___ksymtab_gpl = .;				      \
 			*(__ksymtab_gpl)				      \
 		___stop___ksymtab_gpl = .;				      \
+		/* Kernel symbol table: GPL-future symbols */		      \
+		___start___ksymtab_gpl_future = .;			      \
+			*(__ksymtab_gpl_future)				      \
+		___stop___ksymtab_gpl_future = .;			      \
 		/* Kernel symbol table: strings */			      \
 			*(__ksymtab_strings)				      \
 		/* Kernel symbol table: Normal symbols */		      \
@@ -74,6 +78,10 @@
 		___start___kcrctab_gpl = .;				      \
 			*(__kcrctab_gpl)				      \
 		___stop___kcrctab_gpl = .;				      \
+		/* Kernel symbol table: GPL-future symbols */		      \
+		___start___kcrctab_gpl_future = .;			      \
+			*(__kcrctab_gpl_future)				      \
+		___stop___kcrctab_gpl_future = .;			      \
 		/* Built-in module parameters */			      \
 		. = ALIGN (4) ;						      \
 		___start___param = .;					      \

include/asm-generic/vmlinux.lds.h

@@ -58,6 +58,13 @@
 		VMLINUX_SYMBOL(__stop___ksymtab_gpl) = .;		\
 	}								\
 									\
+	/* Kernel symbol table: GPL-future-only symbols */		\
+	__ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \
+		VMLINUX_SYMBOL(__start___ksymtab_gpl_future) = .;	\
+		*(__ksymtab_gpl_future)					\
+		VMLINUX_SYMBOL(__stop___ksymtab_gpl_future) = .;	\
+	}								\
+									\
 	/* Kernel symbol table: Normal symbols */			\
 	__kcrctab         : AT(ADDR(__kcrctab) - LOAD_OFFSET) {		\
 		VMLINUX_SYMBOL(__start___kcrctab) = .;			\
@@ -72,6 +79,13 @@
 		VMLINUX_SYMBOL(__stop___kcrctab_gpl) = .;		\
 	}								\
 									\
+	/* Kernel symbol table: GPL-future-only symbols */		\
+	__kcrctab_gpl_future : AT(ADDR(__kcrctab_gpl_future) - LOAD_OFFSET) { \
+		VMLINUX_SYMBOL(__start___kcrctab_gpl_future) = .;	\
+		*(__kcrctab_gpl_future)					\
+		VMLINUX_SYMBOL(__stop___kcrctab_gpl_future) = .;	\
+	}								\
+									\
 	/* Kernel symbol table: strings */				\
         __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) {	\
 		*(__ksymtab_strings)					\

include/linux/module.h

@@ -198,6 +198,9 @@ void *__symbol_get_gpl(const char *symbol);
 #define EXPORT_SYMBOL_GPL(sym)					\
 	__EXPORT_SYMBOL(sym, "_gpl")
 
+#define EXPORT_SYMBOL_GPL_FUTURE(sym)				\
+	__EXPORT_SYMBOL(sym, "_gpl_future")
+
 #endif
 
 struct module_ref
@@ -255,6 +258,11 @@ struct module
 	unsigned int num_gpl_syms;
 	const unsigned long *gpl_crcs;
 
+	/* symbols that will be GPL-only in the near future. */
+	const struct kernel_symbol *gpl_future_syms;
+	unsigned int num_gpl_future_syms;
+	const unsigned long *gpl_future_crcs;
+
 	/* Exception table */
 	unsigned int num_exentries;
 	const struct exception_table_entry *extable;
@@ -441,6 +449,7 @@ void module_remove_driver(struct device_driver *);
 #else /* !CONFIG_MODULES... */
 #define EXPORT_SYMBOL(sym)
 #define EXPORT_SYMBOL_GPL(sym)
+#define EXPORT_SYMBOL_GPL_FUTURE(sym)
 
 /* Given an address, look for it in the exception tables. */
 static inline const struct exception_table_entry *

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);

scripts/genksyms/keywords.c_shipped

@@ -52,9 +52,9 @@ is_reserved_hash (register const char *str, register unsigned int len)
       71, 71, 71, 71, 71, 71, 71, 71, 71, 71,
       71, 71, 71, 71, 71, 71, 71, 71, 71, 71,
       71, 71, 71, 71, 71, 71, 71, 71, 71, 71,
-      71, 71, 71, 71, 71, 71, 71, 71, 71, 15,
-      71, 71, 71, 71, 71, 71, 15, 71, 71, 71,
-      10, 71, 71, 71, 71, 71, 71, 71, 71, 71,
+      71, 71, 71, 71, 71, 71, 71, 71, 71,  0,
+      71, 71, 71, 71, 71, 71, 35, 71, 71, 71,
+       5, 71, 71, 71, 71, 71, 71, 71, 71, 71,
       71, 71, 71, 71, 71,  0, 71,  0, 71,  5,
        5,  0, 10, 20, 71, 25, 71, 71, 20,  0,
       20, 30, 25, 71, 10,  5,  0, 20, 15, 71,
@@ -84,9 +84,9 @@ is_reserved_word (register const char *str, register unsigned int len)
 {
   enum
     {
-      TOTAL_KEYWORDS = 41,
+      TOTAL_KEYWORDS = 42,
       MIN_WORD_LENGTH = 3,
-      MAX_WORD_LENGTH = 17,
+      MAX_WORD_LENGTH = 24,
       MIN_HASH_VALUE = 3,
       MAX_HASH_VALUE = 70
     };
@@ -94,104 +94,105 @@ is_reserved_word (register const char *str, register unsigned int len)
   static const struct resword wordlist[] =
     {
       {""}, {""}, {""},
-#line 24 "scripts/genksyms/keywords.gperf"
+#line 25 "scripts/genksyms/keywords.gperf"
       {"asm", ASM_KEYW},
       {""},
-#line 7 "scripts/genksyms/keywords.gperf"
+#line 8 "scripts/genksyms/keywords.gperf"
       {"__asm", ASM_KEYW},
       {""},
-#line 8 "scripts/genksyms/keywords.gperf"
+#line 9 "scripts/genksyms/keywords.gperf"
       {"__asm__", ASM_KEYW},
       {""},
-#line 21 "scripts/genksyms/keywords.gperf"
+#line 22 "scripts/genksyms/keywords.gperf"
       {"_restrict", RESTRICT_KEYW},
-#line 50 "scripts/genksyms/keywords.gperf"
+#line 51 "scripts/genksyms/keywords.gperf"
       {"__typeof__", TYPEOF_KEYW},
-#line 9 "scripts/genksyms/keywords.gperf"
+#line 10 "scripts/genksyms/keywords.gperf"
       {"__attribute", ATTRIBUTE_KEYW},
-#line 11 "scripts/genksyms/keywords.gperf"
+#line 12 "scripts/genksyms/keywords.gperf"
       {"__const", CONST_KEYW},
-#line 10 "scripts/genksyms/keywords.gperf"
+#line 11 "scripts/genksyms/keywords.gperf"
       {"__attribute__", ATTRIBUTE_KEYW},
-#line 12 "scripts/genksyms/keywords.gperf"
+#line 13 "scripts/genksyms/keywords.gperf"
       {"__const__", CONST_KEYW},
-#line 16 "scripts/genksyms/keywords.gperf"
+#line 17 "scripts/genksyms/keywords.gperf"
       {"__signed__", SIGNED_KEYW},
-#line 42 "scripts/genksyms/keywords.gperf"
+#line 43 "scripts/genksyms/keywords.gperf"
       {"static", STATIC_KEYW},
       {""},
-#line 15 "scripts/genksyms/keywords.gperf"
+#line 16 "scripts/genksyms/keywords.gperf"
       {"__signed", SIGNED_KEYW},
-#line 30 "scripts/genksyms/keywords.gperf"
+#line 31 "scripts/genksyms/keywords.gperf"
       {"char", CHAR_KEYW},
       {""},
-#line 43 "scripts/genksyms/keywords.gperf"
+#line 44 "scripts/genksyms/keywords.gperf"
       {"struct", STRUCT_KEYW},
-#line 22 "scripts/genksyms/keywords.gperf"
-      {"__restrict__", RESTRICT_KEYW},
 #line 23 "scripts/genksyms/keywords.gperf"
+      {"__restrict__", RESTRICT_KEYW},
+#line 24 "scripts/genksyms/keywords.gperf"
       {"restrict", RESTRICT_KEYW},
-#line 33 "scripts/genksyms/keywords.gperf"
+#line 34 "scripts/genksyms/keywords.gperf"
       {"enum", ENUM_KEYW},
-#line 17 "scripts/genksyms/keywords.gperf"
+#line 18 "scripts/genksyms/keywords.gperf"
       {"__volatile", VOLATILE_KEYW},
-#line 34 "scripts/genksyms/keywords.gperf"
+#line 35 "scripts/genksyms/keywords.gperf"
       {"extern", EXTERN_KEYW},
-#line 18 "scripts/genksyms/keywords.gperf"
+#line 19 "scripts/genksyms/keywords.gperf"
       {"__volatile__", VOLATILE_KEYW},
-#line 37 "scripts/genksyms/keywords.gperf"
+#line 38 "scripts/genksyms/keywords.gperf"
       {"int", INT_KEYW},
-      {""},
-#line 31 "scripts/genksyms/keywords.gperf"
-      {"const", CONST_KEYW},
+#line 7 "scripts/genksyms/keywords.gperf"
+      {"EXPORT_SYMBOL_GPL_FUTURE", EXPORT_SYMBOL_KEYW},
 #line 32 "scripts/genksyms/keywords.gperf"
+      {"const", CONST_KEYW},
+#line 33 "scripts/genksyms/keywords.gperf"
       {"double", DOUBLE_KEYW},
       {""},
-#line 13 "scripts/genksyms/keywords.gperf"
+#line 14 "scripts/genksyms/keywords.gperf"
       {"__inline", INLINE_KEYW},
-#line 29 "scripts/genksyms/keywords.gperf"
+#line 30 "scripts/genksyms/keywords.gperf"
       {"auto", AUTO_KEYW},
-#line 14 "scripts/genksyms/keywords.gperf"
+#line 15 "scripts/genksyms/keywords.gperf"
       {"__inline__", INLINE_KEYW},
-#line 41 "scripts/genksyms/keywords.gperf"
+#line 42 "scripts/genksyms/keywords.gperf"
       {"signed", SIGNED_KEYW},
       {""},
-#line 46 "scripts/genksyms/keywords.gperf"
+#line 47 "scripts/genksyms/keywords.gperf"
       {"unsigned", UNSIGNED_KEYW},
       {""},
-#line 40 "scripts/genksyms/keywords.gperf"
+#line 41 "scripts/genksyms/keywords.gperf"
       {"short", SHORT_KEYW},
-#line 49 "scripts/genksyms/keywords.gperf"
+#line 50 "scripts/genksyms/keywords.gperf"
       {"typeof", TYPEOF_KEYW},
-#line 44 "scripts/genksyms/keywords.gperf"
+#line 45 "scripts/genksyms/keywords.gperf"
       {"typedef", TYPEDEF_KEYW},
-#line 48 "scripts/genksyms/keywords.gperf"
+#line 49 "scripts/genksyms/keywords.gperf"
       {"volatile", VOLATILE_KEYW},
       {""},
-#line 35 "scripts/genksyms/keywords.gperf"
+#line 36 "scripts/genksyms/keywords.gperf"
       {"float", FLOAT_KEYW},
       {""}, {""},
-#line 39 "scripts/genksyms/keywords.gperf"
+#line 40 "scripts/genksyms/keywords.gperf"
       {"register", REGISTER_KEYW},
-#line 47 "scripts/genksyms/keywords.gperf"
+#line 48 "scripts/genksyms/keywords.gperf"
       {"void", VOID_KEYW},
       {""},
-#line 36 "scripts/genksyms/keywords.gperf"
+#line 37 "scripts/genksyms/keywords.gperf"
       {"inline", INLINE_KEYW},
       {""},
 #line 5 "scripts/genksyms/keywords.gperf"
       {"EXPORT_SYMBOL", EXPORT_SYMBOL_KEYW},
       {""},
-#line 20 "scripts/genksyms/keywords.gperf"
+#line 21 "scripts/genksyms/keywords.gperf"
       {"_Bool", BOOL_KEYW},
       {""},
 #line 6 "scripts/genksyms/keywords.gperf"
       {"EXPORT_SYMBOL_GPL", EXPORT_SYMBOL_KEYW},
       {""}, {""}, {""}, {""}, {""}, {""},
-#line 38 "scripts/genksyms/keywords.gperf"
+#line 39 "scripts/genksyms/keywords.gperf"
       {"long", LONG_KEYW},
       {""}, {""}, {""}, {""}, {""},
-#line 45 "scripts/genksyms/keywords.gperf"
+#line 46 "scripts/genksyms/keywords.gperf"
       {"union", UNION_KEYW}
     };
 

scripts/genksyms/keywords.gperf

@@ -4,6 +4,7 @@ struct resword { const char *name; int token; }
 %%
 EXPORT_SYMBOL, EXPORT_SYMBOL_KEYW
 EXPORT_SYMBOL_GPL, EXPORT_SYMBOL_KEYW
+EXPORT_SYMBOL_GPL_FUTURE, EXPORT_SYMBOL_KEYW
 __asm, ASM_KEYW
 __asm__, ASM_KEYW
 __attribute, ATTRIBUTE_KEYW