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xlat_tables_v2: get unmap action type with helper function.

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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>
This commit is contained in:
David Pu 2019-02-22 02:15:57 -08:00
parent 5ba32a7660
commit 3ff6e401f9
1 changed files with 64 additions and 49 deletions
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113
lib/xlat_tables_v2/xlat_tables_core.c
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@ -233,6 +233,67 @@ typedef enum {
#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 @@ static void xlat_tables_unmap_region(xlat_ctx_t *ctx, mmap_region_t *mm,
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) {