mlkem test diagnostics and allocator updates

sdk/software/examples/mlkem_test/sw_mlkem_alloc.c

@@ -0,0 +1,40 @@
+#include "sw_mlkem_alloc.h"
+
+#include <stdint.h>
+
+#define SW_MLKEM_ALLOC_ALIGN 32u
+#define SW_MLKEM_ALLOC_SIZE  (64u * 1024u)
+
+static uint8_t sw_mlkem_arena[SW_MLKEM_ALLOC_SIZE] __attribute__((aligned(SW_MLKEM_ALLOC_ALIGN)));
+static size_t sw_mlkem_arena_pos;
+static unsigned sw_mlkem_arena_active;
+
+static size_t align_up(size_t n)
+{
+    return (n + (SW_MLKEM_ALLOC_ALIGN - 1u)) & ~(SW_MLKEM_ALLOC_ALIGN - 1u);
+}
+
+void *sw_mlkem_alloc(size_t size)
+{
+    size_t pos = align_up(sw_mlkem_arena_pos);
+    size_t need = align_up(size);
+
+    if (pos + need > SW_MLKEM_ALLOC_SIZE)
+        return 0;
+
+    sw_mlkem_arena_pos = pos + need;
+    sw_mlkem_arena_active++;
+    return &sw_mlkem_arena[pos];
+}
+
+void sw_mlkem_free(void *ptr, size_t size)
+{
+    (void)ptr;
+    (void)size;
+
+    if (sw_mlkem_arena_active != 0)
+        sw_mlkem_arena_active--;
+
+    if (sw_mlkem_arena_active == 0)
+        sw_mlkem_arena_pos = 0;
+}