xnu-6153.61.1.tar.gz

[apple/xnu.git] / san / kasan-fakestack.c

diff --git a/san/kasan-fakestack.c b/san/kasan-fakestack.c
index b023ded1c948529a759ea00ed8039671c119f505..add9941a9cb431e3a63fb7d0d95dd807a1f7cb03 100644 (file)
--- a/san/kasan-fakestack.c
+++ b/san/kasan-fakestack.c
@@ -47,8 +47,9 @@ int fakestack_enabled = 0;
 #define FAKESTACK_HEADER_SZ 64
 #define FAKESTACK_NUM_SZCLASS 7
 
-#define FAKESTACK_FREED     0 /* forced by clang */
+#define FAKESTACK_UNUSED    0 /* waiting to be collected at next gc - forced by clang */
 #define FAKESTACK_ALLOCATED 1
+#define FAKESTACK_FREED     2
 
 #if FAKESTACK
 
@@ -120,29 +121,38 @@ ptr_is_on_stack(uptr ptr)
 }
 
 /* free all unused fakestack entries */
-static void NOINLINE
+void
 kasan_fakestack_gc(thread_t thread)
 {
        struct fakestack_header *cur, *tmp;
        LIST_HEAD(, fakestack_header) tofree = LIST_HEAD_INITIALIZER(tofree);
 
-       /* move all the freed elements off the main list */
+       boolean_t flags;
+       if (!thread_enter_fakestack(&flags)) {
+               panic("expected success entering fakestack\n");
+       }
+
+       /* move the unused objects off the per-thread list... */
        struct fakestack_header_list *head = &kasan_get_thread_data(thread)->fakestack_head;
        LIST_FOREACH_SAFE(cur, head, list, tmp) {
-               if (cur->flag == FAKESTACK_FREED) {
+               if (cur->flag == FAKESTACK_UNUSED) {
                        LIST_REMOVE(cur, list);
                        LIST_INSERT_HEAD(&tofree, cur, list);
+                       cur->flag = FAKESTACK_FREED;
                }
        }
 
+       kasan_unlock(flags);
+
        /* ... then actually free them */
        LIST_FOREACH_SAFE(cur, &tofree, list, tmp) {
+               LIST_REMOVE(cur, list);
+
                zone_t zone = fakestack_zones[cur->sz_class];
                size_t sz = (fakestack_min << cur->sz_class) + FAKESTACK_HEADER_SZ;
-               LIST_REMOVE(cur, list);
 
                void *ptr = (void *)cur;
-               kasan_free_internal(&ptr, &sz, KASAN_HEAP_FAKESTACK, &zone, cur->realsz, 1, FAKESTACK_QUARANTINE);
+               kasan_free_internal(&ptr, &sz, KASAN_HEAP_FAKESTACK, &zone, cur->realsz, 0, FAKESTACK_QUARANTINE);
                if (ptr) {
                        zfree(zone, ptr);
                }
@@ -179,8 +189,6 @@ kasan_fakestack_alloc(int sz_class, size_t realsz)
                return 0;
        }
 
-       kasan_fakestack_gc(current_thread()); /* XXX: optimal? */
-
        ret = (uptr)zget(zone);
 
        if (ret) {
@@ -234,14 +242,14 @@ kasan_fakestack_free(int sz_class, uptr dst, size_t realsz)
 
        kasan_free_internal((void **)&dst, &sz, KASAN_HEAP_FAKESTACK, &zone, realsz, 1, FAKESTACK_QUARANTINE);
        if (dst) {
-               zfree(zone, (void *)dst);
+               zfree(zone, dst);
        }
 
        kasan_unlock(flags);
 }
 
 void NOINLINE
-kasan_unpoison_fakestack(thread_t thread)
+kasan_fakestack_drop(thread_t thread)
 {
        boolean_t flags;
        if (!thread_enter_fakestack(&flags)) {
@@ -252,11 +260,10 @@ kasan_unpoison_fakestack(thread_t thread)
        struct fakestack_header *cur;
        LIST_FOREACH(cur, head, list) {
                if (cur->flag == FAKESTACK_ALLOCATED) {
-                       cur->flag = FAKESTACK_FREED;
+                       cur->flag = FAKESTACK_UNUSED;
                }
        }
 
-       kasan_fakestack_gc(thread);
        kasan_unlock(flags);
 }
 
@@ -279,7 +286,7 @@ kasan_init_fakestack(void)
                assert(z);
                zone_change(z, Z_NOCALLOUT, TRUE);
                zone_change(z, Z_EXHAUST, TRUE);
-               zone_change(z, Z_EXPAND,  FALSE);
+               zone_change(z, Z_EXPAND, FALSE);
                zone_change(z, Z_COLLECT, FALSE);
                zone_change(z, Z_KASAN_QUARANTINE, FALSE);
                zfill(z, maxsz / sz);
@@ -322,7 +329,8 @@ kasan_fakestack_free(int __unused sz_class, uptr __unused dst, size_t __unused r
 
 #endif
 
-void kasan_init_thread(struct kasan_thread_data *td)
+void
+kasan_init_thread(struct kasan_thread_data *td)
 {
        LIST_INIT(&td->fakestack_head);
 }