Merge tag 'm68k-for-v5.12-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-microblaze.git] / kernel / static_call.c

diff --git a/kernel/static_call.c b/kernel/static_call.c
index 84565c2..6906c6e 100644 (file)
--- a/kernel/static_call.c
+++ b/kernel/static_call.c
@@ -12,6 +12,8 @@
 
 extern struct static_call_site __start_static_call_sites[],
                               __stop_static_call_sites[];
+extern struct static_call_tramp_key __start_static_call_tramp_key[],
+                                   __stop_static_call_tramp_key[];
 
 static bool static_call_initialized;
 
@@ -323,10 +325,59 @@ static int __static_call_mod_text_reserved(void *start, void *end)
        return ret;
 }
 
+static unsigned long tramp_key_lookup(unsigned long addr)
+{
+       struct static_call_tramp_key *start = __start_static_call_tramp_key;
+       struct static_call_tramp_key *stop = __stop_static_call_tramp_key;
+       struct static_call_tramp_key *tramp_key;
+
+       for (tramp_key = start; tramp_key != stop; tramp_key++) {
+               unsigned long tramp;
+
+               tramp = (long)tramp_key->tramp + (long)&tramp_key->tramp;
+               if (tramp == addr)
+                       return (long)tramp_key->key + (long)&tramp_key->key;
+       }
+
+       return 0;
+}
+
 static int static_call_add_module(struct module *mod)
 {
-       return __static_call_init(mod, mod->static_call_sites,
-                                 mod->static_call_sites + mod->num_static_call_sites);
+       struct static_call_site *start = mod->static_call_sites;
+       struct static_call_site *stop = start + mod->num_static_call_sites;
+       struct static_call_site *site;
+
+       for (site = start; site != stop; site++) {
+               unsigned long addr = (unsigned long)static_call_key(site);
+               unsigned long key;
+
+               /*
+                * Is the key is exported, 'addr' points to the key, which
+                * means modules are allowed to call static_call_update() on
+                * it.
+                *
+                * Otherwise, the key isn't exported, and 'addr' points to the
+                * trampoline so we need to lookup the key.
+                *
+                * We go through this dance to prevent crazy modules from
+                * abusing sensitive static calls.
+                */
+               if (!kernel_text_address(addr))
+                       continue;
+
+               key = tramp_key_lookup(addr);
+               if (!key) {
+                       pr_warn("Failed to fixup __raw_static_call() usage at: %ps\n",
+                               static_call_addr(site));
+                       return -EINVAL;
+               }
+
+               site->key = (key - (long)&site->key) |
+                           (site->key & STATIC_CALL_SITE_FLAGS);
+       }
+
+       return __static_call_init(mod, start, stop);
 }
 
 static void static_call_del_module(struct module *mod)
@@ -438,6 +489,11 @@ int __init static_call_init(void)
 }
 early_initcall(static_call_init);
 
+long __static_call_return0(void)
+{
+       return 0;
+}
+
 #ifdef CONFIG_STATIC_CALL_SELFTEST
 
 static int func_a(int x)