diff mbox series

[Concept,08/37] malloc: Add mem_malloc_init() and sbrk()

Message ID 20251201170529.3237986-9-sjg@u-boot.org
State New
Headers
Series malloc: Import dlmalloc 2.8.6 |

Commit Message

Simon Glass Dec. 1, 2025, 5:04 p.m. UTC 
  From: Simon Glass <simon.glass@canonical.com>

Add mem_malloc_init() to initialise the malloc heap and sbrk() for
heap extension. These are U-Boot-specific functions that manage the
memory pool used by dlmalloc.

Co-developed-by: Claude <noreply@anthropic.com>
Signed-off-by: Simon Glass <simon.glass@canonical.com>
---

 common/dlmalloc.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++
 include/malloc.h  | 27 +++++++++++++++++++++++++
 2 files changed, 78 insertions(+)
diff mbox series

Patch

diff --git a/common/dlmalloc.c b/common/dlmalloc.c
index ba8ca5bd0ae..2be2262ebeb 100644
--- a/common/dlmalloc.c
+++ b/common/dlmalloc.c
@@ -542,6 +542,18 @@  MAX_RELEASE_CHECK_RATE   default: 4095 unless not HAVE_MMAP
 #define DLMALLOC_EXPORT extern
 #endif
 
+#ifdef __UBOOT__
+#include <mapmem.h>
+#include <asm/global_data.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+ulong mem_malloc_start;
+ulong mem_malloc_end;
+ulong mem_malloc_brk;
+
+#endif /* __UBOOT__ */
+
 #ifndef WIN32
 #ifdef _WIN32
 #define WIN32 1
@@ -6290,3 +6302,42 @@  History:
          structure of old version,  but most details differ.)
 
 */
+
+/* --------------------- U-Boot additions --------------------- */
+
+#ifdef __UBOOT__
+
+void *sbrk(ptrdiff_t increment)
+{
+	ulong old = mem_malloc_brk;
+	ulong new = old + increment;
+
+	/* mem_malloc_end points one byte past the end, so >= is correct */
+	if ((new < mem_malloc_start) || (new >= mem_malloc_end))
+		return (void *)MORECORE_FAILURE;
+
+	/*
+	 * if we are giving memory back make sure we clear it out since
+	 * we set MORECORE_CLEARS to 1
+	 */
+	if (increment < 0)
+		memset((void *)new, '\0', -increment);
+
+	mem_malloc_brk = new;
+
+	return (void *)old;
+}
+
+void mem_malloc_init(ulong start, ulong size)
+{
+	mem_malloc_start = (ulong)map_sysmem(start, size);
+	mem_malloc_end = mem_malloc_start + size;
+	mem_malloc_brk = mem_malloc_end;
+
+	debug("using memory %#lx-%#lx for malloc()\n", mem_malloc_start,
+	      mem_malloc_end);
+#if CONFIG_IS_ENABLED(SYS_MALLOC_CLEAR_ON_INIT)
+	memset((void *)mem_malloc_start, '\0', size);
+#endif
+}
+#endif /* __UBOOT__ */
diff --git a/include/malloc.h b/include/malloc.h
index 4608082d2e0..e0a5b732203 100644
--- a/include/malloc.h
+++ b/include/malloc.h
@@ -625,6 +625,33 @@  void mspace_inspect_all(mspace msp,
                         void* arg);
 #endif  /* MSPACES */
 
+/* --------------------- U-Boot additions --------------------- */
+
+#ifdef __UBOOT__
+#include <linux/types.h>
+
+/* Memory pool boundaries */
+extern ulong mem_malloc_start;
+extern ulong mem_malloc_end;
+extern ulong mem_malloc_brk;
+
+/**
+ * mem_malloc_init() - Initialize the malloc() heap
+ *
+ * @start: Start address of heap memory region
+ * @size: Size of heap memory region in bytes
+ */
+void mem_malloc_init(ulong start, ulong size);
+
+/**
+ * sbrk() - Extend the heap
+ *
+ * @increment: Number of bytes to add (or remove if negative)
+ * Return: Previous break value on success, MORECORE_FAILURE on error
+ */
+void *sbrk(ptrdiff_t increment);
+#endif /* __UBOOT__ */
+
 #ifdef __cplusplus
 };  /* end of extern "C" */
 #endif