fix(heap): memalign respect malloc_alwaysinternal_limit

This changes `memalign` (and `posix_memalign`) so that it uses an
allocation method with the same selection criteria (checking
`malloc_alwaysinternal_limit` and picking one of:

- always MALLOC_CAP_INTERNAL
- MALLOC_CAP_INTERNAL first with fallback
- MALLOC_CAP_SPIRAM first with fallback

`malloc_alwaysinternal_limit` is in turn set by the options
`CONFIG_SPIRAM_MALLOC_ALWAYSINTERNAL` and
`CONFIG_SPRIAM_USE_CAPS_ALLOC`.

This notably affects folks using esp-rs to build rust code for the
esp-idf, as all allocations from rust use `memalign`.

Merges https://github.com/espressif/esp-idf/pull/12375

components/heap/heap_caps.c

@@ -660,31 +660,8 @@ size_t heap_caps_get_allocated_size( void *ptr )
     return MULTI_HEAP_REMOVE_BLOCK_OWNER_SIZE(size);
 }
 
-HEAP_IRAM_ATTR void *heap_caps_aligned_alloc(size_t alignment, size_t size, uint32_t caps)
+static HEAP_IRAM_ATTR void *heap_caps_aligned_alloc_base(size_t alignment, size_t size, uint32_t caps)
 {
-    void *ret = NULL;
-
-    if(!alignment) {
-        return NULL;
-    }
-
-    //Alignment must be a power of two:
-    if((alignment & (alignment - 1)) != 0) {
-        return NULL;
-    }
-
-    if (size == 0) {
-        return NULL;
-    }
-
-    if (MULTI_HEAP_ADD_BLOCK_OWNER_SIZE(size) > HEAP_SIZE_MAX) {
-        // Avoids int overflow when adding small numbers to size, or
-        // calculating 'end' from start+size, by limiting 'size' to the possible range
-        heap_caps_alloc_failed(size, caps, __func__);
-
-        return NULL;
-    }
-
     for (int prio = 0; prio < SOC_MEMORY_TYPE_NO_PRIOS; prio++) {
         //Iterate over heaps and check capabilities at this priority
         heap_t *heap;
@@ -697,7 +674,7 @@ HEAP_IRAM_ATTR void *heap_caps_aligned_alloc(size_t alignment, size_t size, uint
                 //doesn't cover, see if they're available in other prios.
                 if ((get_all_caps(heap) & caps) == caps) {
                     //Just try to alloc, nothing special.
-                    ret = multi_heap_aligned_alloc(heap->heap, MULTI_HEAP_ADD_BLOCK_OWNER_SIZE(size), alignment);
+                    void *ret = multi_heap_aligned_alloc(heap->heap, MULTI_HEAP_ADD_BLOCK_OWNER_SIZE(size), alignment);
                     if (ret != NULL) {
                         MULTI_HEAP_SET_BLOCK_OWNER(ret);
                         ret = MULTI_HEAP_ADD_BLOCK_OWNER_OFFSET(ret);
@@ -709,12 +686,83 @@ HEAP_IRAM_ATTR void *heap_caps_aligned_alloc(size_t alignment, size_t size, uint
         }
     }
 
-    heap_caps_alloc_failed(size, caps, __func__);
-
     //Nothing usable found.
     return NULL;
 }
 
+static HEAP_IRAM_ATTR esp_err_t heap_caps_aligned_check_args(size_t alignment, size_t size, uint32_t caps, const char *funcname)
+{
+    if (!alignment) {
+        return ESP_FAIL;
+    }
+
+    // Alignment must be a power of two:
+    if ((alignment & (alignment - 1)) != 0) {
+        return ESP_FAIL;
+    }
+
+    if (size == 0) {
+        return ESP_FAIL;
+    }
+
+    if (MULTI_HEAP_ADD_BLOCK_OWNER_SIZE(size) > HEAP_SIZE_MAX) {
+        // Avoids int overflow when adding small numbers to size, or
+        // calculating 'end' from start+size, by limiting 'size' to the possible range
+        heap_caps_alloc_failed(size, caps, funcname);
+        return ESP_FAIL;
+    }
+
+    return ESP_OK;
+}
+
+HEAP_IRAM_ATTR void *heap_caps_aligned_alloc_default(size_t alignment, size_t size)
+{
+    void *ret = NULL;
+
+    if (malloc_alwaysinternal_limit == MALLOC_DISABLE_EXTERNAL_ALLOCS) {
+        return heap_caps_aligned_alloc(alignment, size, MALLOC_CAP_DEFAULT | MALLOC_CAP_INTERNAL);
+    }
+
+    if (heap_caps_aligned_check_args(alignment, size, MALLOC_CAP_DEFAULT, __func__) != ESP_OK) {
+        return NULL;
+    }
+
+    if (size <= (size_t)malloc_alwaysinternal_limit) {
+        ret = heap_caps_aligned_alloc_base(alignment, size, MALLOC_CAP_DEFAULT | MALLOC_CAP_INTERNAL);
+    } else {
+        ret = heap_caps_aligned_alloc_base(alignment, size, MALLOC_CAP_DEFAULT | MALLOC_CAP_SPIRAM);
+    }
+
+    if (ret != NULL) {
+        return ret;
+    }
+
+    ret = heap_caps_aligned_alloc_base(alignment, size, MALLOC_CAP_DEFAULT);
+
+    if (ret == NULL) {
+        heap_caps_alloc_failed(size, MALLOC_CAP_DEFAULT, __func__);
+    }
+
+    return ret;
+}
+
+HEAP_IRAM_ATTR void *heap_caps_aligned_alloc(size_t alignment, size_t size, uint32_t caps)
+{
+    void *ret = NULL;
+
+    if (heap_caps_aligned_check_args(alignment, size, caps, __func__) != ESP_OK) {
+        return NULL;
+    }
+
+    ret = heap_caps_aligned_alloc_base(alignment, size, caps);
+
+    if (ret == NULL) {
+        heap_caps_alloc_failed(size, caps, __func__);
+    }
+
+    return ret;
+}
+
 HEAP_IRAM_ATTR void heap_caps_aligned_free(void *ptr)
 {
     heap_caps_free(ptr);