2007-08-11 Zoltan Varga <vargaz@gmail.com>

[mono.git] / mono / mini / exceptions-amd64.c

diff --git a/mono/mini/exceptions-amd64.c b/mono/mini/exceptions-amd64.c
index 01c45f32ead8223da49f11df39e718a9e707b534..bacd5948ce5b5d9350b95665092f125fb7906b21 100644 (file)
--- a/mono/mini/exceptions-amd64.c
+++ b/mono/mini/exceptions-amd64.c
@@ -23,6 +23,7 @@
 #include <mono/metadata/exception.h>
 #include <mono/metadata/gc-internal.h>
 #include <mono/metadata/mono-debug.h>
+#include <mono/utils/mono-mmap.h>
 
 #include "mini.h"
 #include "mini-amd64.h"
@@ -750,14 +751,42 @@ mono_arch_ip_from_context (void *sigctx)
 }
 
 static void
-altstack_handle_and_restore (void *sigctx, gpointer obj, gboolean test_only)
+restore_soft_guard_pages (void)
+{
+       MonoJitTlsData *jit_tls = TlsGetValue (mono_jit_tls_id);
+       if (jit_tls->stack_ovf_guard_base)
+               mono_mprotect (jit_tls->stack_ovf_guard_base, jit_tls->stack_ovf_guard_size, MONO_MMAP_NONE);
+}
+
+/* 
+ * this function modifies mctx so that when it is restored, it
+ * won't execcute starting at mctx.eip, but in a function that
+ * will restore the protection on the soft-guard pages and return back to
+ * continue at mctx.eip.
+ */
+static void
+prepare_for_guard_pages (MonoContext *mctx)
+{
+       gpointer *sp;
+       sp = (gpointer)(mctx->rsp);
+       sp -= 1;
+       /* the return addr */
+       sp [0] = (gpointer)(mctx->rip);
+       mctx->rip = (unsigned long)restore_soft_guard_pages;
+       mctx->rsp = (unsigned long)sp;
+}
+
+static void
+altstack_handle_and_restore (void *sigctx, gpointer obj, gboolean stack_ovf)
 {
        void (*restore_context) (MonoContext *);
        MonoContext mctx;
 
        restore_context = mono_arch_get_restore_context ();
        mono_arch_sigctx_to_monoctx (sigctx, &mctx);
-       mono_handle_exception (&mctx, obj, MONO_CONTEXT_GET_IP (&mctx), test_only);
+       mono_handle_exception (&mctx, obj, MONO_CONTEXT_GET_IP (&mctx), FALSE);
+       if (stack_ovf)
+               prepare_for_guard_pages (&mctx);
        restore_context (&mctx);
 }
 
@@ -765,25 +794,18 @@ void
 mono_arch_handle_altstack_exception (void *sigctx, gpointer fault_addr, gboolean stack_ovf)
 {
 #ifdef MONO_ARCH_USE_SIGACTION
+       MonoException *exc = NULL;
        ucontext_t *ctx = (ucontext_t*)sigctx;
        guint64 *gregs = gregs_from_ucontext (ctx);
        MonoJitInfo *ji = mono_jit_info_table_find (mono_domain_get (), (gpointer)gregs [REG_RIP]);
        gpointer *sp;
        int frame_size;
 
-       if (stack_ovf) {
-               const char *method;
-               /* we don't do much now, but we can warn the user with a useful message */
-               fprintf (stderr, "Stack overflow: IP: %p, SP: %p\n", (gpointer)gregs [REG_RIP], (gpointer)gregs [REG_RSP]);
-               if (ji && ji->method)
-                       method = mono_method_full_name (ji->method, TRUE);
-               else
-                       method = "Unmanaged";
-               fprintf (stderr, "At %s\n", method);
-               abort ();
-       }
+       if (stack_ovf)
+               exc = mono_domain_get ()->stack_overflow_ex;
        if (!ji)
                mono_handle_native_sigsegv (SIGSEGV, sigctx);
+
        /* setup a call frame on the real stack so that control is returned there
         * and exception handling can continue.
         * The frame looks like:
@@ -805,8 +827,8 @@ mono_arch_handle_altstack_exception (void *sigctx, gpointer fault_addr, gboolean
        gregs [REG_RIP] = (unsigned long)altstack_handle_and_restore;
        gregs [REG_RSP] = (unsigned long)(sp - 1);
        gregs [REG_RDI] = (unsigned long)(sp + 4);
-       gregs [REG_RSI] = 0;
-       gregs [REG_RDX] = 0;
+       gregs [REG_RSI] = (guint64)exc;
+       gregs [REG_RDX] = stack_ovf;
 #endif
 }