rt: Don't zero new stacks

src/rt/rust_kernel.h

@@ -59,6 +59,7 @@ public:
     void *malloc(size_t size, const char *tag);
     void *realloc(void *mem, size_t size);
     void free(void *mem);
+    memory_region *region() { return &_region; }
 
     void fail();
 

src/rt/rust_stack.cpp

@@ -41,3 +41,20 @@ void
 check_stack_canary(stk_seg *stk) {
     assert(stk->canary == canary_value && "Somebody killed the canary");
 }
+
+stk_seg *
+create_stack(memory_region *region, size_t sz) {
+    size_t total_sz = sizeof(stk_seg) + sz;
+    stk_seg *stk = (stk_seg *)region->malloc(total_sz, "stack", false);
+    memset(stk, 0, sizeof(stk_seg));
+    stk->end = (uintptr_t) &stk->data[sz];
+    add_stack_canary(stk);
+    register_valgrind_stack(stk);
+    return stk;
+}
+
+void
+destroy_stack(memory_region *region, stk_seg *stk) {
+    deregister_valgrind_stack(stk);
+    region->free(stk);
+}

src/rt/rust_stack.h

@@ -1,6 +1,8 @@
 #ifndef RUST_STACK_H
 #define RUST_STACK_H
 
+#include "memory_region.h"
+
 struct stk_seg {
     stk_seg *prev;
     stk_seg *next;
@@ -15,36 +17,11 @@ struct stk_seg {
     uint8_t data[];
 };
 
-// Used by create_stack
-void
-register_valgrind_stack(stk_seg *stk);
-
-// Used by destroy_stack
-void
-deregister_valgrind_stack(stk_seg *stk);
-
-// Used by create_stack
-void
-add_stack_canary(stk_seg *stk);
-
-template <class T>
 stk_seg *
-create_stack(T allocer, size_t sz) {
-  size_t total_sz = sizeof(stk_seg) + sz;
-  stk_seg *stk = (stk_seg *)allocer->malloc(total_sz, "stack");
-  memset(stk, 0, sizeof(stk_seg));
-  stk->end = (uintptr_t) &stk->data[sz];
-  add_stack_canary(stk);
-  register_valgrind_stack(stk);
-  return stk;
-}
+create_stack(memory_region *region, size_t sz);
 
-template <class T>
 void
-destroy_stack(T allocer, stk_seg *stk) {
-  deregister_valgrind_stack(stk);
-  allocer->free(stk);
-}
+destroy_stack(memory_region *region, stk_seg *stk);
 
 // Must be called before each time a stack is reused to tell valgrind
 // that the stack is accessible.

src/rt/rust_task.cpp

@@ -552,7 +552,7 @@ void
 rust_task::free_stack(stk_seg *stk) {
     LOGPTR(thread, "freeing stk segment", (uintptr_t)stk);
     total_stack_sz -= user_stack_size(stk);
-    destroy_stack(this, stk);
+    destroy_stack(&local_region, stk);
 }
 
 void
@@ -596,7 +596,7 @@ rust_task::new_stack(size_t requested_sz) {
     }
 
     size_t sz = rust_stk_sz + RED_ZONE_SIZE;
-    stk_seg *new_stk = create_stack(this, sz);
+    stk_seg *new_stk = create_stack(&local_region, sz);
     LOGPTR(thread, "new stk", (uintptr_t)new_stk);
     new_stk->prev = NULL;
     new_stk->next = stk;

src/rt/rust_task_thread.cpp

@@ -290,7 +290,7 @@ rust_task_thread::start_main_loop() {
 
     I(this, !extra_c_stack);
     if (cached_c_stack) {
-        destroy_stack(kernel, cached_c_stack);
+        destroy_stack(kernel->region(), cached_c_stack);
         cached_c_stack = NULL;
     }
 }
@@ -369,7 +369,7 @@ void
 rust_task_thread::prepare_c_stack(rust_task *task) {
     I(this, !extra_c_stack);
     if (!cached_c_stack && !task->have_c_stack()) {
-        cached_c_stack = create_stack(kernel, C_STACK_SIZE);
+        cached_c_stack = create_stack(kernel->region(), C_STACK_SIZE);
         prepare_valgrind_stack(cached_c_stack);
     }
 }
@@ -377,7 +377,7 @@ rust_task_thread::prepare_c_stack(rust_task *task) {
 void
 rust_task_thread::unprepare_c_stack() {
     if (extra_c_stack) {
-        destroy_stack(kernel, extra_c_stack);
+        destroy_stack(kernel->region(), extra_c_stack);
         extra_c_stack = NULL;
     }
 }