[GitHub] [nuttx] xiaoxiang781216 commented on a diff in pull request #9368: mm/kmm_map: Add support to dynamically map pages into kernel virtual …

["xiaoxiang781216 (via GitHub)" <gi...@apache.org>]

xiaoxiang781216 commented on code in PR #9368:
URL: https://github.com/apache/nuttx/pull/9368#discussion_r1213150169


##########
mm/kmap/kmm_map.c:
##########
@@ -0,0 +1,466 @@
+/****************************************************************************
+ * mm/kmap/kmm_map.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <stddef.h>
+
+#include <nuttx/addrenv.h>
+#include <nuttx/arch.h>
+#include <nuttx/compiler.h>
+#include <nuttx/kmalloc.h>
+#include <nuttx/mm/gran.h>
+#include <nuttx/mm/map.h>
+#include <nuttx/pgalloc.h>
+#include <nuttx/sched.h>
+
+#include <sys/mman.h>
+
+#if defined(CONFIG_BUILD_KERNEL)
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static GRAN_HANDLE     g_kmm_map_vpages;
+static struct mm_map_s g_kmm_map;
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: get_user_pages
+ *
+ * Description:
+ *   Get the physical pages mapped to a user virtual memory region.
+ *
+ * Input Parameters:
+ *   pages  - Pointer to buffer where the page addresses are recorded.
+ *   npages - Amount of pages.
+ *   vaddr  - Start address of the user virtual memory region.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned
+ *   on failure.
+ *
+ ****************************************************************************/
+
+static int get_user_pages(FAR void **pages, size_t npages, uintptr_t vaddr)
+{
+  FAR struct tcb_s *tcb = nxsched_self();
+  uintptr_t         page;
+  int               i;
+
+  /* Find the pages associated with the user virtual address space */
+
+  for (i = 0; i < npages; i++, vaddr += MM_PGSIZE)
+    {
+      page = up_addrenv_find_page(&tcb->addrenv_own->addrenv, vaddr);
+      if (!page)
+        {
+          /* Something went wrong, get out */
+
+          return -EINVAL;
+        }
+
+      pages[i] = (FAR void *)page;
+    }
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: map_pages
+ *
+ * Description:
+ *   Map pages into kernel virtual memory.
+ *
+ * Input Parameters:
+ *   pages  - Pointer to buffer that contains the physical page addresses.
+ *   npages - Amount of pages.
+ *   prot   - Access right flags.
+ *
+ * Returned Value:
+ *   Pointer to the mapped virtual memory on success; NULL on failure
+ *
+ ****************************************************************************/
+
+static void *map_pages(FAR void **pages, size_t npages, int prot)
+{
+  struct mm_map_entry_s entry;
+  FAR void             *vaddr;
+  size_t                size;
+  int                   ret;
+
+  /* The region size is full pages */
+
+  size = npages << MM_PGSHIFT;
+
+  /* Find a virtual memory area that fits */
+
+  vaddr = gran_alloc(&g_kmm_map_vpages, size);
+  if (!vaddr)
+    {
+      return NULL;
+    }
+
+  /* Map the pages into the kernel page directory */
+
+  ret = up_addrenv_kmap_pages(pages, npages, (uintptr_t)vaddr, prot);
+  if (ret < 0)
+    {
+      goto errout_with_vaddr;
+    }
+
+  entry.vaddr = vaddr;
+  entry.length = size;
+  entry.offset = 0;
+  entry.munmap = NULL;
+
+  ret = mm_map_add(&g_kmm_map, &entry);
+  if (ret < 0)
+    {
+      goto errout_with_pgmap;
+    }
+
+  return vaddr;
+
+errout_with_pgmap:
+  up_addrenv_kunmap_pages((uintptr_t)vaddr, npages);
+errout_with_vaddr:
+  gran_free(&g_kmm_map_vpages, vaddr, size);
+  return NULL;
+}
+
+/****************************************************************************
+ * Name: map_single_user_page
+ *
+ * Description:
+ *   Map a single user page into kernel memory.
+ *
+ * Input Parameters:
+ *   pages  - Pointer to buffer that contains the physical page addresses.
+ *   npages - Amount of pages.
+ *   prot   - Access right flags.
+ *
+ * Returned Value:
+ *   Pointer to the mapped virtual memory on success; NULL on failure
+ *
+ ****************************************************************************/
+
+static void *map_single_user_page(uintptr_t vaddr)
+{
+  FAR struct tcb_s *tcb = nxsched_self();
+  uintptr_t         page;
+
+  /* Find the page associated with this virtual address */
+
+  page = up_addrenv_find_page(&tcb->addrenv_own->addrenv, vaddr);
+  if (!page)
+    {
+      return NULL;
+    }
+
+  vaddr = up_addrenv_page_vaddr(page);
+  return (FAR void *)vaddr;
+}
+
+/****************************************************************************
+ * Name: kmm_map_lock
+ *
+ * Description:
+ *   Get exclusive access to the kernel mm_map
+ *
+ ****************************************************************************/
+
+static int kmm_map_lock(void)
+{
+  return nxrmutex_lock(&g_kmm_map.mm_map_mutex);
+}
+
+/****************************************************************************
+ * Name: kmm_map_unlock
+ *
+ * Description:
+ *   Relinquish exclusive access to the kernel mm_map
+ *
+ ****************************************************************************/
+
+static void kmm_map_unlock(void)
+{
+  DEBUGVERIFY(nxrmutex_unlock(&g_kmm_map.mm_map_mutex));
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: kmm_map_initialize
+ *
+ * Description:
+ *   Initialize the kernel dynamic mapping module.
+ *
+ * Input Parameters:
+ *   None.
+ *
+ * Returned Value:
+ *   None.
+ *
+ ****************************************************************************/
+
+void kmm_map_initialize(void)
+{
+  g_kmm_map_vpages = gran_initialize((FAR void *)CONFIG_ARCH_KMAP_VBASE,
+                                     CONFIG_ARCH_KMAP_NPAGES << MM_PGSHIFT,
+                                     MM_PGSHIFT, MM_PGSHIFT);
+  DEBUGVERIFY(g_kmm_map_vpages);
+  mm_map_initialize(&g_kmm_map, true);
+}
+
+/****************************************************************************
+ * Name: kmm_map_pages
+ *
+ * Description:
+ *   Map pages into kernel virtual memory.
+ *
+ * Input Parameters:
+ *   pages  - Pointer to buffer that contains the physical page addresses.
+ *   npages - Amount of pages.
+ *   prot   - Access right flags.
+ *
+ * Returned Value:
+ *   Pointer to the mapped virtual memory on success; NULL on failure
+ *
+ ****************************************************************************/
+
+FAR void *kmm_map(FAR void **pages, size_t npages, int prot)
+{
+  uintptr_t vaddr;
+
+  if (!pages || !npages || npages > CONFIG_ARCH_KMAP_NPAGES)
+    {
+      return NULL;
+    }
+
+  /* Attempt to map the pages */
+
+  vaddr = (uintptr_t)map_pages(pages, npages, prot);
+  if (!vaddr)
+    {
+      return NULL;
+    }
+
+  return (FAR void *)(vaddr);

Review Comment:
   remove () around vaddr



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