Changeset 14655

Timestamp:

Feb 21, 2011, 12:23:44 AM (14 years ago)

Author:

Gary Byers

Message:

Handle SIGBUS: if we get a SIGBUS trying to access the page before our
soft guard pages, map the page and let other mechanisms (those guard
pages, the check in rmark()) deal with (pending) overflow. (This is
to work around the problem noted in
​http://clozure.com/pipermail/openmcl-devel/2011-January/012498.html,
which seems to be present in new Linux kernels, at least on the ARM.)

File:

• trunk/source/lisp-kernel/arm-exceptions.c (modified) (2 diffs)

trunk/source/lisp-kernel/arm-exceptions.c

@@ -1486 +1486 @@
 {
   TCR *tcr=get_tcr(true);
-  if (signo == SIGSEGV) {
+  
+  if (signo == SIGBUS) {
+    BytePtr addr = (BytePtr)(xp->uc_mcontext.fault_address); 
+    area *a = tcr->cs_area;
+    if (((BytePtr)truncate_to_power_of_2(addr,log2_page_size))== a->softlimit) 
+{
+      if (mmap(a->softlimit,
+               page_size,
+               PROT_READ|PROT_WRITE|PROT_EXEC,
+               MAP_PRIVATE|MAP_ANON|MAP_FIXED,
+               -1,
+               0) == a->softlimit) {
+        return;
+      }
+    }
+  } else if (signo == SIGSEGV) {
     BytePtr addr = (BytePtr)(xp->uc_mcontext.fault_address);
     area *a = tcr->cs_area;
@@ -1799 +1814 @@
     install_signal_handler(SIGILL, (void *)sigill_handler, true, false);
     install_signal_handler(SIGSEGV, (void *)ALTSTACK(signal_handler),true, true);
+    install_signal_handler(SIGBUS, (void *)ALTSTACK(signal_handler),true,true);
 
   }