xlat_tables_v2: get unmap action type with helper function.
This patch introduces helper function 'xlat_tables_unmap_region_action'
to get the required action type from given arguments when unmapping the
specified region.
it reduces cyclomatic code complexity in xlat_tables_unmap_region function.
Cyclomatic complexity calculated using 'Coverity'
fixes arm-software/tf-issues#673
Signed-off-by: David Pu <dpu@nvidia.com>
diff --git a/lib/xlat_tables_v2/xlat_tables_core.c b/lib/xlat_tables_v2/xlat_tables_core.c
index d7d8c22..a39dfc9 100644
--- a/lib/xlat_tables_v2/xlat_tables_core.c
+++ b/lib/xlat_tables_v2/xlat_tables_core.c
@@ -234,6 +234,67 @@
#if PLAT_XLAT_TABLES_DYNAMIC
/*
+ * From the given arguments, it decides which action to take when unmapping the
+ * specified region.
+ */
+static action_t xlat_tables_unmap_region_action(const mmap_region_t *mm,
+ const uintptr_t table_idx_va, const uintptr_t table_idx_end_va,
+ const unsigned int level, const uint64_t desc_type)
+{
+ action_t action;
+ uintptr_t region_end_va = mm->base_va + mm->size - 1U;
+
+ if ((mm->base_va <= table_idx_va) &&
+ (region_end_va >= table_idx_end_va)) {
+ /* Region covers all block */
+
+ if (level == 3U) {
+ /*
+ * Last level, only page descriptors allowed,
+ * erase it.
+ */
+ assert(desc_type == PAGE_DESC);
+
+ action = ACTION_WRITE_BLOCK_ENTRY;
+ } else {
+ /*
+ * Other levels can have table descriptors. If
+ * so, recurse into it and erase descriptors
+ * inside it as needed. If there is a block
+ * descriptor, just erase it. If an invalid
+ * descriptor is found, this table isn't
+ * actually mapped, which shouldn't happen.
+ */
+ if (desc_type == TABLE_DESC) {
+ action = ACTION_RECURSE_INTO_TABLE;
+ } else {
+ assert(desc_type == BLOCK_DESC);
+ action = ACTION_WRITE_BLOCK_ENTRY;
+ }
+ }
+
+ } else if ((mm->base_va <= table_idx_end_va) ||
+ (region_end_va >= table_idx_va)) {
+ /*
+ * Region partially covers block.
+ *
+ * It can't happen in level 3.
+ *
+ * There must be a table descriptor here, if not there
+ * was a problem when mapping the region.
+ */
+ assert(level < 3U);
+ assert(desc_type == TABLE_DESC);
+
+ action = ACTION_RECURSE_INTO_TABLE;
+ } else {
+ /* The region doesn't cover the block at all */
+ action = ACTION_NONE;
+ }
+
+ return action;
+}
+/*
* Recursive function that writes to the translation tables and unmaps the
* specified region.
*/
@@ -276,55 +337,9 @@
desc = table_base[table_idx];
uint64_t desc_type = desc & DESC_MASK;
- action_t action;
-
- if ((mm->base_va <= table_idx_va) &&
- (region_end_va >= table_idx_end_va)) {
- /* Region covers all block */
-
- if (level == 3U) {
- /*
- * Last level, only page descriptors allowed,
- * erase it.
- */
- assert(desc_type == PAGE_DESC);
-
- action = ACTION_WRITE_BLOCK_ENTRY;
- } else {
- /*
- * Other levels can have table descriptors. If
- * so, recurse into it and erase descriptors
- * inside it as needed. If there is a block
- * descriptor, just erase it. If an invalid
- * descriptor is found, this table isn't
- * actually mapped, which shouldn't happen.
- */
- if (desc_type == TABLE_DESC) {
- action = ACTION_RECURSE_INTO_TABLE;
- } else {
- assert(desc_type == BLOCK_DESC);
- action = ACTION_WRITE_BLOCK_ENTRY;
- }
- }
-
- } else if ((mm->base_va <= table_idx_end_va) ||
- (region_end_va >= table_idx_va)) {
- /*
- * Region partially covers block.
- *
- * It can't happen in level 3.
- *
- * There must be a table descriptor here, if not there
- * was a problem when mapping the region.
- */
- assert(level < 3U);
- assert(desc_type == TABLE_DESC);
-
- action = ACTION_RECURSE_INTO_TABLE;
- } else {
- /* The region doesn't cover the block at all */
- action = ACTION_NONE;
- }
+ action_t action = xlat_tables_unmap_region_action(mm,
+ table_idx_va, table_idx_end_va, level,
+ desc_type);
if (action == ACTION_WRITE_BLOCK_ENTRY) {