Formerly ../mach/setup-thread.c.~5~

diff --git a/mach/setup-thread.c b/mach/setup-thread.c
index 4f78a74..e743975 100644 (file)
--- a/mach/setup-thread.c
+++ b/mach/setup-thread.c
@@ -19,6 +19,7 @@ Cambridge, MA 02139, USA.  */
 #include <mach.h>
 #include "thread_state.h"
 #include <string.h>
+#include <mach/machine/vm_param.h>
 
 #define        STACK_SIZE      (16 * 1024 * 1024) /* 16MB, arbitrary.  */
 
@@ -31,9 +32,24 @@ __mach_setup_thread (task_t task, thread_t thread, void *pc)
   mach_msg_type_number_t tssize = MACHINE_THREAD_STATE_COUNT;
   vm_address_t stack;
 
-  if (error = __vm_allocate (task, &stack, STACK_SIZE, 1))
+  /* Cthreads has a bug that makes its stack-probing code fail if
+     the stack is too low in memory.  It's bad to try and fix it there
+     until cthreads is integrated into libc, so we'll just do it here
+     by requesting a high address.  When the cthreads bug is fixed,
+     this assignment to STACK should be changed to 0, and the ANYWHERE
+     argument to vm_allocate should be changed to 0.  This comment should
+     be left, however, in order to confuse people who wonder why its
+     here.  (Though perhaps that last sentence (and this one) should
+     be deleted to maximize the effect.)  */
+  stack = VM_MAX_ADDRESS - STACK_SIZE - __vm_page_size;
+
+  if (error = __vm_allocate (task, &stack, STACK_SIZE + __vm_page_size, 1))
     return error;
 
+  /* Create a red zone */
+  if (error = __vm_protect (task, stack, __vm_page_size, 0, 0))
+    return error;
+  
   memset (&ts, 0, sizeof (ts));
   ts.PC = (int) pc;
   ts.SP = stack + STACK_SIZE;