2010-02-15 Zoltan Varga <vargaz@gmail.com>

[mono.git] / mono / mini / aot-runtime.c

diff --git a/mono/mini/aot-runtime.c b/mono/mini/aot-runtime.c
index 9c8fdc07d8897868a711bc739bff5634f9648d8f..7f02b7593c66057a462593390cbf3ab581b6a34f 100644 (file)
--- a/mono/mini/aot-runtime.c
+++ b/mono/mini/aot-runtime.c
@@ -162,6 +162,7 @@ static gint32 mono_last_aot_method = -1;
 
 static gboolean make_unreadable = FALSE;
 static guint32 name_table_accesses = 0;
+static guint32 n_pagefaults = 0;
 
 /* Used to speed-up find_aot_module () */
 static gsize aot_code_low_addr = (gssize)-1;
@@ -1175,17 +1176,19 @@ load_aot_module (MonoAssembly *assembly, gpointer user_data)
        if (make_unreadable) {
 #ifndef TARGET_WIN32
                guint8 *addr;
-               guint8 *page_start;
-               int pages, err, len;
+               guint8 *page_start, *page_end;
+               int err, len;
 
                addr = amodule->mem_begin;
                len = amodule->mem_end - amodule->mem_begin;
 
                /* Round down in both directions to avoid modifying data which is not ours */
                page_start = (guint8 *) (((gssize) (addr)) & ~ (mono_pagesize () - 1)) + mono_pagesize ();
-               pages = ((addr + len - page_start + mono_pagesize () - 1) / mono_pagesize ()) - 1;
-               err = mono_mprotect (page_start, pages * mono_pagesize (), MONO_MMAP_NONE);
-               g_assert (err == 0);
+               page_end = (guint8 *) (((gssize) (addr + len)) & ~ (mono_pagesize () - 1));
+               if (page_end > page_start) {
+                       err = mono_mprotect (page_start, (page_end - page_start), MONO_MMAP_NONE);
+                       g_assert (err == 0);
+               }
 #endif
        }
 
@@ -2000,6 +2003,7 @@ decode_exception_debug_info (MonoAotModule *amodule, MonoDomain *domain,
                int len = decode_value (p, &p);
 
                seq_points = g_malloc0 (sizeof (MonoSeqPointInfo) + (len - MONO_ZERO_LEN_ARRAY) * sizeof (SeqPoint));
+               seq_points->len = len;
                last_il_offset = last_native_offset = 0;
                for (i = 0; i < len; ++i) {
                        SeqPoint *sp = &seq_points->seq_points [i];
@@ -3573,6 +3577,98 @@ mono_aot_get_imt_thunk (MonoVTable *vtable, MonoDomain *domain, MonoIMTCheckItem
 
        return code;
 }
+ 
+/*
+ * mono_aot_set_make_unreadable:
+ *
+ *   Set whenever to make all mmaped memory unreadable. In conjuction with a
+ * SIGSEGV handler, this is useful to find out which pages the runtime tries to read.
+ */
+void
+mono_aot_set_make_unreadable (gboolean unreadable)
+{
+       static int inited;
+
+       make_unreadable = unreadable;
+
+       if (make_unreadable && !inited) {
+               mono_counters_register ("AOT pagefaults", MONO_COUNTER_JIT | MONO_COUNTER_INT, &n_pagefaults);
+       }               
+}
+
+typedef struct {
+       MonoAotModule *module;
+       guint8 *ptr;
+} FindMapUserData;
+
+static void
+find_map (gpointer key, gpointer value, gpointer user_data)
+{
+       MonoAotModule *module = (MonoAotModule*)value;
+       FindMapUserData *data = (FindMapUserData*)user_data;
+
+       if (!data->module)
+               if ((data->ptr >= module->mem_begin) && (data->ptr < module->mem_end))
+                       data->module = module;
+}
+
+static MonoAotModule*
+find_module_for_addr (void *ptr)
+{
+       FindMapUserData data;
+
+       if (!make_unreadable)
+               return NULL;
+
+       data.module = NULL;
+       data.ptr = (guint8*)ptr;
+
+       mono_aot_lock ();
+       g_hash_table_foreach (aot_modules, (GHFunc)find_map, &data);
+       mono_aot_unlock ();
+
+       return data.module;
+}
+
+/*
+ * mono_aot_is_pagefault:
+ *
+ *   Should be called from a SIGSEGV signal handler to find out whenever @ptr is
+ * within memory allocated by this module.
+ */
+gboolean
+mono_aot_is_pagefault (void *ptr)
+{
+       if (!make_unreadable)
+               return FALSE;
+
+       /* 
+        * Not signal safe, but SIGSEGV's are synchronous, and
+        * this is only turned on by a MONO_DEBUG option.
+        */
+       return find_module_for_addr (ptr) != NULL;
+}
+
+/*
+ * mono_aot_handle_pagefault:
+ *
+ *   Handle a pagefault caused by an unreadable page by making it readable again.
+ */
+void
+mono_aot_handle_pagefault (void *ptr)
+{
+#ifndef PLATFORM_WIN32
+       guint8* start = (guint8*)ROUND_DOWN (((gssize)ptr), mono_pagesize ());
+       int res;
+
+       mono_aot_lock ();
+       res = mono_mprotect (start, mono_pagesize (), MONO_MMAP_READ|MONO_MMAP_WRITE|MONO_MMAP_EXEC);
+       g_assert (res == 0);
+
+       n_pagefaults ++;
+       mono_aot_unlock ();
+#endif
+}
 
 #else
 /* AOT disabled */