add src/assert.c, fix rt_atomic macro and use it for pointers also

arch/arm/arm.c

@@ -1,4 +1,3 @@
-#include <rt/assert.h>
 #include <rt/context.h>
 #include <rt/cycle.h>
 #include <rt/idle.h>
@@ -77,17 +76,6 @@ void rt_syscall(void)
     __asm__("svc 0" ::: "memory");
 }
 
-static const char *volatile rt_assert_msg;
-
-__attribute__((weak)) void rt_assert(bool condition, const char *msg)
-{
-    if (!condition)
-    {
-        rt_assert_msg = msg;
-        rt_trap();
-    }
-}
-
 #if V6M
 #include "m/atomic-v6.c"
 #endif

include/rt/assert.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <rt/atomic.h>
+
 #include <stdbool.h>
 
 #ifdef __cplusplus

include/rt/atomic.h

@@ -14,7 +14,7 @@ extern "C" {
  * _Atomic as a macro in stdatomic.h, in terms of std::atomic. */
 #define rt_atomic(t) _Atomic(t)
 #else
-#define rt_atomic(t) _Atomic t
+#define rt_atomic(t) t _Atomic
 #endif
 
 typedef rt_atomic(bool) rt_atomic_bool;

src/SConscript

@@ -3,6 +3,7 @@ Import("env")
 librt = env.StaticLibrary(
     target="rt",
     source=[
+        "assert.c",
         "barrier.c",
         "cond.c",
         "list.c",

src/assert.c

@@ -0,0 +1,15 @@
+#include <rt/assert.h>
+
+#include <rt/atomic.h>
+#include <rt/trap.h>
+
+static rt_atomic(const char *) rt_assert_msg;
+
+__attribute__((weak)) void rt_assert(bool condition, const char *msg)
+{
+    if (!condition)
+    {
+        rt_atomic_store(&rt_assert_msg, msg, RT_ATOMIC_SEQ_CST);
+        rt_trap();
+    }
+}

src/rt.c

@@ -100,7 +100,7 @@ static void insert_mutex_by_priority(struct rt_list *list,
 
 /* rt_pending_syscalls can be updated from user code, so we don't put it
  * in RT_MPU_PRIV_BSS. */
-static struct rt_syscall_record *_Atomic rt_pending_syscalls = NULL;
+static rt_atomic(struct rt_syscall_record *) rt_pending_syscalls = NULL;
 
 RT_TASK(rt_idle, RT_STACK_MIN, 0);