diff --git a/photon/libc/sys/magenta/__heap.h b/photon/libc/sys/magenta/__heap.h
new file mode 100644
index 0000000..5b49cdf
--- /dev/null
+++ b/photon/libc/sys/magenta/__heap.h
@@ -0,0 +1,8 @@
+#ifndef SYS_MAGENTA_HEAP_H_
+#define SYS_MAGENTA_HEAP_H_
+
+#include "__init.h"
+
+extern int __heap_init(struct __proc_start_info *info);
+
+#endif
diff --git a/photon/libc/sys/magenta/init.h b/photon/libc/sys/magenta/__init.h
similarity index 82%
rename from photon/libc/sys/magenta/init.h
rename to photon/libc/sys/magenta/__init.h
index 4fc3596..2b959ca 100644
--- a/photon/libc/sys/magenta/init.h
+++ b/photon/libc/sys/magenta/__init.h
@@ -9,6 +9,8 @@ struct __proc_start_info {
     mx_handle_t err;
     int argc;
     const char **argv;
+    mx_handle_t heap;
+    void *heap_map_base;
 };
 
 #endif
diff --git a/photon/libc/sys/magenta/config.cmake b/photon/libc/sys/magenta/config.cmake
index 383e863..f6289f8 100644
--- a/photon/libc/sys/magenta/config.cmake
+++ b/photon/libc/sys/magenta/config.cmake
@@ -1,3 +1,5 @@
 set(photon_platform_extra_source_dirs libmagenta/libmagenta)
-set(photon_platform_extra_include_dirs libmagenta/libmagenta/arch/${machine})
+set(photon_platform_extra_include_dirs
+    libmagenta/libmagenta
+    libmagenta/libmagenta/arch/${machine})
 set(photon_platform_libs magenta)
diff --git a/photon/libc/sys/magenta/heap.c b/photon/libc/sys/magenta/heap.c
new file mode 100644
index 0000000..d82d77f
--- /dev/null
+++ b/photon/libc/sys/magenta/heap.c
@@ -0,0 +1,41 @@
+#include <magenta.h>
+#include <stdint.h>
+#include <stddef.h>
+#include "__init.h"
+#include "__heap.h"
+
+#define ROUND_UP(x, b) x += (b) - ((x) % (b))
+
+static uintptr_t heap_start = 0;
+static uintptr_t heap_end = 0;
+static size_t heap_sz = 0;
+static mx_handle_t heap_segment = MX_NULL_HANDLE;
+
+int __heap_init(struct __proc_start_info *info)
+{
+    heap_start = (uintptr_t)info->heap_map_base;
+    heap_end = (uintptr_t)info + sizeof(*info);
+    ROUND_UP(heap_end, 0x1000);
+    heap_segment = info->heap;
+
+    unsigned long sz = 0;
+    mx_segment_get_size(heap_segment, &sz);
+    heap_sz = sz;
+
+    return 0;
+}
+
+void *__extend_heap(size_t sz)
+{
+    if (sz == 0) {
+        return (void *)(heap_end + 1);
+    }
+
+    void *start = (void *)heap_start;
+
+    uintptr_t ret = heap_end;
+    mx_segment_set_size(heap_segment, heap_sz + sz);
+    mx_segment_map(heap_segment, 0, heap_sz + sz, &start);
+    heap_end += sz;
+    return (void *)ret;
+}
diff --git a/photon/libc/sys/magenta/init.c b/photon/libc/sys/magenta/init.c
index ff26ba7..e300fb0 100644
--- a/photon/libc/sys/magenta/init.c
+++ b/photon/libc/sys/magenta/init.c
@@ -1,4 +1,5 @@
-#include "init.h"
+#include "__init.h"
+#include "__heap.h"
 #include "__fio.h"
 
 extern int main(int, const char **);
@@ -6,5 +7,6 @@ extern int main(int, const char **);
 int __crt_init(struct __proc_start_info *info)
 {
     __fio_init(info->in, info->out, info->err);
+    __heap_init(info);
     return main(info->argc, info->argv);
 }
diff --git a/photon/libc/sys/magenta/libmagenta b/photon/libc/sys/magenta/libmagenta
index 04ccced..51e77c9 160000
--- a/photon/libc/sys/magenta/libmagenta
+++ b/photon/libc/sys/magenta/libmagenta
@@ -1 +1 @@
-Subproject commit 04ccced9d4c2e1251e2fce89d084c93ce8ac3527
+Subproject commit 51e77c9cfdb9988e55df4f56257c8ab0dadda1b1