Add a layer to redirect kernel-mode memory manager accesses

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3466 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 110 insertions, 0 deletions

diff --git a/nuttx/sched/kmm_kfree.c b/nuttx/sched/kmm_kfree.c
new file mode 100644
index 000000000..0370ce8ee
--- /dev/null
+++ b/nuttx/sched/kmm_kfree.c
@@ -0,0 +1,110 @@
+/************************************************************************
+ * sched/kmm_kfree.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ************************************************************************/
+
+/************************************************************************
+ * Included Files
+ ************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/kmalloc.h>
+
+#ifdef CONFIG_NUTTX_KERNEL
+
+/* This logic is all tentatively and, hopefully, will grow in usability.
+ * For now, the kernel-mode build uses the memory manager that is
+ * provided in the user-space build.  That is awkward but reasonable for
+ * the current level of support:  At present, only memory protection is
+ * provided.  Kernel-mode code may call into user-mode code, but not
+ * vice-versa.  So hosting the memory manager in user-space allows the
+ * memory manager to be shared in both kernel- and user-mode spaces.
+ *
+ * In the longer run, if an MMU is support that can provide virtualized
+ * memory, then some SLAB memory manager will be required in kernel-space
+ * with some kind of brk() system call to obtain mapped heap space.
+ *
+ * In the current build model, the user-space module is built first. The
+ * file user_map.h is generated in the first pass and contains the
+ * addresses of the memory manager needed in this file:
+ */
+
+#include <arch/board/user_map.h>
+
+/************************************************************************
+ * Pre-processor definition
+ ************************************************************************/
+
+/* This value is obtained from user_map.h */
+
+#define KFREE(p) ((kfree_t)CONFIG_USER_FREE)(p)
+
+/************************************************************************
+ * Private Types
+ ************************************************************************/
+
+typedef void (*kfree_t)(FAR void *);
+
+/************************************************************************
+ * Private Functions
+ ************************************************************************/
+
+/************************************************************************
+ * Public Functions
+ ************************************************************************/
+
+/************************************************************************
+ * Function:  kfree
+ *
+ * Description:
+ *   This is a simple redirection to the user-space free() function.
+ *
+ * Parameters:
+ *   None
+ *
+ * Return Value:
+ *   None
+ *
+ * Assumptions:
+ *   1. free() resides in user-space
+ *   2. The address of the user space free() is provided in user_map.h
+ *   3. The user-space free() is callable from kernel-space.
+ *
+ ************************************************************************/
+
+void free(FAR void *mem)
+{
+  return KFREE(mem);
+}
+
+#endif /* CONFIG_NUTTX_KERNEL */