-void *SIMIX_context_stack_new()
-{
- void *stack;
-
- /* FIXME: current code for stack overflow protection assumes that stacks are
- * growing downward (PTH_STACKGROWTH == -1). Protected pages need to be put
- * after the stack when PTH_STACKGROWTH == 1. */
-
- if (smx_context_guard_size > 0 && not MC_is_active()) {
-
-#if !defined(PTH_STACKGROWTH) || (PTH_STACKGROWTH != -1)
- static int warned_once = 0;
- if (not warned_once) {
- XBT_WARN("Stack overflow protection is known to be broken on your system. Either stack grows upwards, or it was not even tested properly.");
- warned_once = 1;
- }
-#endif
-
- size_t size = smx_context_stack_size + smx_context_guard_size;
-#if SIMGRID_HAVE_MC
- /* Cannot use posix_memalign when SIMGRID_HAVE_MC. Align stack by hand, and save the
- * pointer returned by xbt_malloc0. */
- char *alloc = (char*)xbt_malloc0(size + xbt_pagesize);
- stack = alloc - ((uintptr_t)alloc & (xbt_pagesize - 1)) + xbt_pagesize;
- *((void **)stack - 1) = alloc;
-#elif !defined(_WIN32)
- if (posix_memalign(&stack, xbt_pagesize, size) != 0)
- xbt_die("Failed to allocate stack.");
-#else
- stack = _aligned_malloc(size, xbt_pagesize);
-#endif
-
-#ifndef _WIN32
- if (mprotect(stack, smx_context_guard_size, PROT_NONE) == -1) {
- xbt_die(
- "Failed to protect stack: %s.\n"
- "If you are running a lot of actors, you may be exceeding the amount of mappings allowed per process.\n"
- "On Linux systems, change this value with sudo sysctl -w vm.max_map_count=newvalue (default value: 65536)\n"
- "Please see http://simgrid.gforge.inria.fr/simgrid/latest/doc/html/options.html#options_virt for more info.",
- strerror(errno));
- /* This is fatal. We are going to fail at some point when we try reusing this. */
- }
-#endif
- stack = (char *)stack + smx_context_guard_size;
- } else {
- stack = xbt_malloc0(smx_context_stack_size);
- }
-
-#if HAVE_VALGRIND_H
- unsigned int valgrind_stack_id = VALGRIND_STACK_REGISTER(stack, (char *)stack + smx_context_stack_size);
- memcpy((char *)stack + smx_context_usable_stack_size, &valgrind_stack_id, sizeof valgrind_stack_id);
-#endif
-
- return stack;
-}
-
-void SIMIX_context_stack_delete(void *stack)
-{
- if (not stack)
- return;
-
-#if HAVE_VALGRIND_H
- unsigned int valgrind_stack_id;
- memcpy(&valgrind_stack_id, (char *)stack + smx_context_usable_stack_size, sizeof valgrind_stack_id);
- VALGRIND_STACK_DEREGISTER(valgrind_stack_id);
-#endif
-
-#ifndef _WIN32
- if (smx_context_guard_size > 0 && not MC_is_active()) {
- stack = (char *)stack - smx_context_guard_size;
- if (mprotect(stack, smx_context_guard_size, PROT_READ | PROT_WRITE) == -1) {
- XBT_WARN("Failed to remove page protection: %s", strerror(errno));
- /* try to pursue anyway */
- }
-#if SIMGRID_HAVE_MC
- /* Retrieve the saved pointer. See SIMIX_context_stack_new above. */
- stack = *((void **)stack - 1);
-#endif
- }
-#endif /* not windows */
-
- xbt_free(stack);
-}
-