1 files changed, 112 insertions, 0 deletions
diff --git a/circuitpython/supervisor/shared/stack.c b/circuitpython/supervisor/shared/stack.c
new file mode 100644
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+++ b/circuitpython/supervisor/shared/stack.c
@@ -0,0 +1,112 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "stack.h"
+
+#include "py/mpconfig.h"
+#include "py/runtime.h"
+#include "supervisor/cpu.h"
+#include "supervisor/port.h"
+#include "supervisor/shared/safe_mode.h"
+
+extern uint32_t _estack;
+
+// Requested size.
+static uint32_t next_stack_size = CIRCUITPY_DEFAULT_STACK_SIZE;
+static uint32_t current_stack_size = 0;
+// Actual location and size, may be larger than requested.
+static uint32_t *stack_limit = NULL;
+static size_t stack_length = 0;
+
+#define EXCEPTION_STACK_SIZE 1024
+
+static void allocate_stack(void) {
+
+    if (port_has_fixed_stack()) {
+        stack_limit = port_stack_get_limit();
+        stack_length = (port_stack_get_top() - stack_limit) * sizeof(uint32_t);
+        current_stack_size = stack_length;
+    } else {
+        mp_uint_t regs[10];
+        mp_uint_t sp = cpu_get_regs_and_sp(regs);
+
+        mp_uint_t c_size = (mp_uint_t)port_stack_get_top() - sp;
+        supervisor_allocation *stack_alloc = allocate_memory(c_size + next_stack_size + EXCEPTION_STACK_SIZE, true, false);
+        if (stack_alloc == NULL) {
+            stack_alloc = allocate_memory(c_size + CIRCUITPY_DEFAULT_STACK_SIZE + EXCEPTION_STACK_SIZE, true, false);
+            current_stack_size = CIRCUITPY_DEFAULT_STACK_SIZE;
+        } else {
+            current_stack_size = next_stack_size;
+        }
+        stack_limit = stack_alloc->ptr;
+        stack_length = get_allocation_length(stack_alloc);
+    }
+
+    *stack_limit = STACK_CANARY_VALUE;
+}
+
+inline bool stack_ok(void) {
+    return stack_limit == NULL || *stack_limit == STACK_CANARY_VALUE;
+}
+
+inline void assert_heap_ok(void) {
+    if (!stack_ok()) {
+        reset_into_safe_mode(HEAP_OVERWRITTEN);
+    }
+}
+
+void stack_init(void) {
+    allocate_stack();
+}
+
+void stack_resize(void) {
+    if (stack_limit == NULL) {
+        return;
+    }
+    if (next_stack_size == current_stack_size) {
+        *stack_limit = STACK_CANARY_VALUE;
+        return;
+    }
+    free_memory(allocation_from_ptr(stack_limit));
+    stack_limit = NULL;
+    allocate_stack();
+}
+
+uint32_t *stack_get_bottom(void) {
+    return stack_limit;
+}
+
+size_t stack_get_length(void) {
+    return stack_length;
+}
+
+void set_next_stack_size(uint32_t size) {
+    next_stack_size = size;
+}
+
+uint32_t get_current_stack_size(void) {
+    return current_stack_size;
+}