xlat lib: Don't set mmap_attr_t enum to be -1

-1 is not a defined mmap_attr_t type. Instead of using invalid enum
types, we can either choose to define a INVALID type OR handle the
condition specifically.

Since the usage of mmap_region_attr is limited, it is easier to just
handle the error condition specifically and return 0 or -1 depending
on success or fail.

Fixes: ARM-Software/tf-issues#473
Fixes: 28fa2e9ee8f4 ("xlat lib: Use mmap_attr_t type consistently")
Signed-off-by: Nishanth Menon <nm@ti.com>

diff --git a/lib/xlat_tables/xlat_tables_common.c b/lib/xlat_tables/xlat_tables_common.c
index 4426ccefb68199cf8f4fe4a57748f16d22e07ccc..23f3daa8c302fb8bd8ad8c4b52118a5918847a3c 100644 (file)
--- a/lib/xlat_tables/xlat_tables_common.c
+++ b/lib/xlat_tables/xlat_tables_common.c
@@ -273,15 +273,19 @@ static uint64_t mmap_desc(mmap_attr_t attr, unsigned long long addr_pa,
 }
 
 /*
- * Returns attributes of area at `base_va` with size `size`. It returns the
- * attributes of the innermost region that contains it. If there are partial
- * overlaps, it returns -1, as a smaller size is needed.
+ * Look for the innermost region that contains the area at `base_va` with size
+ * `size`. Populate *attr with the attributes of this region.
+ *
+ * On success, this function returns 0.
+ * If there are partial overlaps (meaning that a smaller size is needed) or if
+ * the region can't be found in the given area, it returns -1. In this case the
+ * value pointed by attr should be ignored by the caller.
  */
-static mmap_attr_t mmap_region_attr(mmap_region_t *mm, uintptr_t base_va,
-                                       size_t size)
+static int mmap_region_attr(mmap_region_t *mm, uintptr_t base_va,
+                                       size_t size, mmap_attr_t *attr)
 {
        /* Don't assume that the area is contained in the first region */
-       mmap_attr_t attr = -1;
+       int ret = -1;
 
        /*
         * Get attributes from last (innermost) region that contains the
@@ -301,23 +305,25 @@ static mmap_attr_t mmap_region_attr(mmap_region_t *mm, uintptr_t base_va,
        for (;; ++mm) {
 
                if (!mm->size)
-                       return attr; /* Reached end of list */
+                       return ret; /* Reached end of list */
 
                if (mm->base_va > base_va + size - 1)
-                       return attr; /* Next region is after area so end */
+                       return ret; /* Next region is after area so end */
 
                if (mm->base_va + mm->size - 1 < base_va)
                        continue; /* Next region has already been overtaken */
 
-               if (mm->attr == attr)
+               if (!ret && mm->attr == *attr)
                        continue; /* Region doesn't override attribs so skip */
 
                if (mm->base_va > base_va ||
                        mm->base_va + mm->size - 1 < base_va + size - 1)
                        return -1; /* Region doesn't fully cover our area */
 
-               attr = mm->attr;
+               *attr = mm->attr;
+               ret = 0;
        }
+       return ret;
 }
 
 static mmap_region_t *init_xlation_table_inner(mmap_region_t *mm,
@@ -360,9 +366,10 @@ static mmap_region_t *init_xlation_table_inner(mmap_region_t *mm,
                         * there are partially overlapping regions. On success,
                         * it will return the innermost region's attributes.
                         */
-                       mmap_attr_t attr = mmap_region_attr(mm, base_va,
-                                                       level_size);
-                       if (attr >= 0) {
+                       mmap_attr_t attr;
+                       int r = mmap_region_attr(mm, base_va, level_size, &attr);
+
+                       if (!r) {
                                desc = mmap_desc(attr,
                                        base_va - mm->base_va + mm->base_pa,
                                        level);