lx_emul: add lx_emul_heap_alloc/free

Allocator for not-DMA-capable meta data buffers.

Issue #4809

repos/dde_linux/src/include/lx_emul/alloc.h

@@ -1,6 +1,7 @@
 /*
  * \brief  Lx_emul support to allocate memory
  * \author Stefan Kalkowski
+ * \author Christian Helmuth
  * \date   2021-03-25
  */
 
@@ -27,6 +28,13 @@ unsigned long lx_emul_mem_size(const void * ptr);
 void  lx_emul_mem_cache_clean_invalidate(const void * ptr, unsigned long size);
 void  lx_emul_mem_cache_invalidate(const void * ptr, unsigned long size);
 
+/*
+ * Heap for lx_emul metadata - cleared but unprepared for Linux code
+ */
+
+void * lx_emul_heap_alloc(unsigned long size);
+void lx_emul_heap_free(void * ptr);
+
 #ifdef __cplusplus
 }
 #endif

repos/dde_linux/src/lib/lx_emul/alloc.cc

@@ -1,6 +1,7 @@
 /*
  * \brief  Lx_emul backend for memory allocation
  * \author Stefan Kalkowski
+ * \author Christian Helmuth
  * \date   2021-03-22
  */
 
@@ -17,6 +18,7 @@
 #include <lx_emul/page_virt.h>
 #include <lx_kit/env.h>
 
+
 extern "C" void * lx_emul_mem_alloc_aligned(unsigned long size, unsigned long align)
 {
 	void * const ptr = Lx_kit::env().memory.alloc(size, align);
@@ -93,3 +95,22 @@ extern "C" void lx_emul_mem_cache_invalidate(const void * addr,
 {
 	Genode::cache_invalidate_data((Genode::addr_t)addr, size);
 }
+
+
+/*
+ * Heap for lx_emul metadata - unprepared for Linux code
+ */
+
+void * lx_emul_heap_alloc(unsigned long size)
+{
+	void *ptr = Lx_kit::env().heap.alloc(size);
+	if (ptr)
+		Genode::memset(ptr, 0, size);
+	return ptr;
+}
+
+
+void lx_emul_heap_free(void * ptr)
+{
+	Lx_kit::env().heap.free(ptr, 0);
+}