Import of the watch repository from Pebble

src/fw/kernel/kernel_heap.c

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "drivers/task_watchdog.h"
+#include "kernel_heap.h"
+#include "mcu/interrupts.h"
+#include "services/common/analytics/analytics.h"
+
+#define CMSIS_COMPATIBLE
+#include <mcu.h>
+
+static Heap s_kernel_heap;
+static bool s_interrupts_disabled_by_heap;
+static uint32_t s_pri_mask; // cache basepri mask we restore to in heap_unlock
+
+// Locking callbacks for our kernel heap.
+// FIXME: Note that we use __set_BASEPRI() instead of a mutex because our heap
+// has to be used before we even initialize FreeRTOS. We don't use
+// __disable_irq() because we want to catch any hangs in the heap code with our
+// high priority watchdog so that a coredump is triggered.
+
+static void prv_heap_lock(void *ctx) {
+  if (mcu_state_are_interrupts_enabled()) {
+    s_pri_mask = __get_BASEPRI();
+    __set_BASEPRI((TASK_WATCHDOG_PRIORITY + 1) << (8 - __NVIC_PRIO_BITS));
+    s_interrupts_disabled_by_heap = true;
+  }
+}
+
+static void prv_heap_unlock(void *ctx) {
+  if (s_interrupts_disabled_by_heap) {
+    __set_BASEPRI(s_pri_mask);
+    s_interrupts_disabled_by_heap = false;
+  }
+}
+
+void kernel_heap_init(void) {
+  extern int _heap_start;
+  extern int _heap_end;
+
+  heap_init(&s_kernel_heap, &_heap_start, &_heap_end, true);
+  heap_set_lock_impl(&s_kernel_heap, (HeapLockImpl) {
+    .lock_function = prv_heap_lock,
+    .unlock_function = prv_heap_unlock
+  });
+}
+
+void analytics_external_collect_kernel_heap_stats(void) {
+  uint32_t headroom = heap_get_minimum_headroom(&s_kernel_heap);
+  // Reset the high water mark so we can see if there are certain periods of time
+  // where we really tax the heap
+  s_kernel_heap.high_water_mark = s_kernel_heap.current_size;
+  analytics_set(ANALYTICS_DEVICE_METRIC_KERNEL_HEAP_MIN_HEADROOM_BYTES, headroom,
+                AnalyticsClient_System);
+}
+
+Heap* kernel_heap_get(void) {
+  return &s_kernel_heap;
+}
+
+// Serial Commands
+///////////////////////////////////////////////////////////
+#ifdef MALLOC_INSTRUMENTATION
+void command_dump_malloc_kernel(void) {
+  heap_dump_malloc_instrumentation_to_dbgserial(&s_kernel_heap);
+}
+#endif