xlat v2: Support mapping regions with allocated VA

Provide new APIs to add new regions without specifying the base VA.

- `mmap_add_region_alloc_va` adds a static region to mmap choosing as
  base VA the first possible address after all the currently mapped
  regions. It is aligned to an appropriate boundary in relation to the
  size and base PA of the requested region. No attempt is made to fill
  any unused VA holes.

- `mmap_add_dynamic_region_alloc_va` it adds a region the same way as
  `mmap_add_region_alloc_va` does, but it's dynamic instead of static.

- `mmap_add_alloc_va` takes an array of non const `mmap_region_t`,
  maps them in the same way as `mmap_add_region_alloc_va` and fills
  their `base_va` field. A helper macro has been created to help create
  the array, called `MAP_REGION_ALLOC_VA`.

Change-Id: I5ef3f82ca0dfd0013d2e8034aa22f13ca528ba37
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

2 files changed, 124 insertions, 0 deletions

diff --git a/lib/xlat_tables_v2/xlat_tables_context.c b/lib/xlat_tables_v2/xlat_tables_context.c
index f1807745..b887427a 100644
--- a/lib/xlat_tables_v2/xlat_tables_context.c
+++ b/lib/xlat_tables_v2/xlat_tables_context.c
@@ -38,6 +38,25 @@ void mmap_add(const mmap_region_t *mm)
 	mmap_add_ctx(&tf_xlat_ctx, mm);
 }
 
+void mmap_add_region_alloc_va(unsigned long long base_pa, uintptr_t *base_va,
+			      size_t size, unsigned int attr)
+{
+	mmap_region_t mm = MAP_REGION_ALLOC_VA(base_pa, size, attr);
+
+	mmap_add_region_alloc_va_ctx(&tf_xlat_ctx, &mm);
+
+	*base_va = mm.base_va;
+}
+
+void mmap_add_alloc_va(mmap_region_t *mm)
+{
+	while (mm->granularity != 0U) {
+		assert(mm->base_va == 0U);
+		mmap_add_region_alloc_va_ctx(&tf_xlat_ctx, mm);
+		mm++;
+	}
+}
+
 #if PLAT_XLAT_TABLES_DYNAMIC
 
 int mmap_add_dynamic_region(unsigned long long base_pa, uintptr_t base_va,
@@ -48,6 +67,20 @@ int mmap_add_dynamic_region(unsigned long long base_pa, uintptr_t base_va,
 	return mmap_add_dynamic_region_ctx(&tf_xlat_ctx, &mm);
 }
 
+int mmap_add_dynamic_region_alloc_va(unsigned long long base_pa,
+				     uintptr_t *base_va, size_t size,
+				     unsigned int attr)
+{
+	mmap_region_t mm = MAP_REGION_ALLOC_VA(base_pa, size, attr);
+
+	int rc = mmap_add_dynamic_region_alloc_va_ctx(&tf_xlat_ctx, &mm);
+
+	*base_va = mm.base_va;
+
+	return rc;
+}
+
+
 int mmap_remove_dynamic_region(uintptr_t base_va, size_t size)
 {
 	return mmap_remove_dynamic_region_ctx(&tf_xlat_ctx,
diff --git a/lib/xlat_tables_v2/xlat_tables_core.c b/lib/xlat_tables_v2/xlat_tables_core.c
index 8ced76e4..185473a1 100644
--- a/lib/xlat_tables_v2/xlat_tables_core.c
+++ b/lib/xlat_tables_v2/xlat_tables_core.c
@@ -811,6 +811,80 @@ void mmap_add_region_ctx(xlat_ctx_t *ctx, const mmap_region_t *mm)
 		ctx->max_va = end_va;
 }
 
+/*
+ * Determine the table level closest to the initial lookup level that
+ * can describe this translation. Then, align base VA to the next block
+ * at the determined level.
+ */
+static void mmap_alloc_va_align_ctx(xlat_ctx_t *ctx, mmap_region_t *mm)
+{
+	/*
+	 * By or'ing the size and base PA the alignment will be the one
+	 * corresponding to the smallest boundary of the two of them.
+	 *
+	 * There are three different cases. For example (for 4 KiB page size):
+	 *
+	 * +--------------+------------------++--------------+
+	 * | PA alignment | Size multiple of || VA alignment |
+	 * +--------------+------------------++--------------+
+	 * |     2 MiB    |       2 MiB      ||     2 MiB    | (1)
+	 * |     2 MiB    |       4 KiB      ||     4 KiB    | (2)
+	 * |     4 KiB    |       2 MiB      ||     4 KiB    | (3)
+	 * +--------------+------------------++--------------+
+	 *
+	 * - In (1), it is possible to take advantage of the alignment of the PA
+	 *   and the size of the region to use a level 2 translation table
+	 *   instead of a level 3 one.
+	 *
+	 * - In (2), the size is smaller than a block entry of level 2, so it is
+	 *   needed to use a level 3 table to describe the region or the library
+	 *   will map more memory than the desired one.
+	 *
+	 * - In (3), even though the region has the size of one level 2 block
+	 *   entry, it isn't possible to describe the translation with a level 2
+	 *   block entry because of the alignment of the base PA.
+	 *
+	 *   Only bits 47:21 of a level 2 block descriptor are used by the MMU,
+	 *   bits 20:0 of the resulting address are 0 in this case. Because of
+	 *   this, the PA generated as result of this translation is aligned to
+	 *   2 MiB. The PA that was requested to be mapped is aligned to 4 KiB,
+	 *   though, which means that the resulting translation is incorrect.
+	 *   The only way to prevent this is by using a finer granularity.
+	 */
+	unsigned long long align_check;
+
+	align_check = mm->base_pa | (unsigned long long)mm->size;
+
+	/*
+	 * Assume it is always aligned to level 3. There's no need to check that
+	 * level because its block size is PAGE_SIZE. The checks to verify that
+	 * the addresses and size are aligned to PAGE_SIZE are inside
+	 * mmap_add_region.
+	 */
+	for (unsigned int level = ctx->base_level; level <= 2U; ++level) {
+
+		if ((align_check & XLAT_BLOCK_MASK(level)) != 0U)
+			continue;
+
+		mm->base_va = round_up(mm->base_va, XLAT_BLOCK_SIZE(level));
+		return;
+	}
+}
+
+void mmap_add_region_alloc_va_ctx(xlat_ctx_t *ctx, mmap_region_t *mm)
+{
+	mm->base_va = ctx->max_va + 1UL;
+
+	assert(mm->size > 0U);
+
+	mmap_alloc_va_align_ctx(ctx, mm);
+
+	/* Detect overflows. More checks are done in mmap_add_region_check(). */
+	assert(mm->base_va > ctx->max_va);
+
+	mmap_add_region_ctx(ctx, mm);
+}
+
 void mmap_add_ctx(xlat_ctx_t *ctx, const mmap_region_t *mm)
 {
 	const mmap_region_t *mm_cursor = mm;
@@ -931,6 +1005,23 @@ int mmap_add_dynamic_region_ctx(xlat_ctx_t *ctx, mmap_region_t *mm)
 	return 0;
 }
 
+int mmap_add_dynamic_region_alloc_va_ctx(xlat_ctx_t *ctx, mmap_region_t *mm)
+{
+	mm->base_va = ctx->max_va + 1UL;
+
+	if (mm->size == 0U)
+		return 0;
+
+	mmap_alloc_va_align_ctx(ctx, mm);
+
+	/* Detect overflows. More checks are done in mmap_add_region_check(). */
+	if (mm->base_va < ctx->max_va) {
+		return -ENOMEM;
+	}
+
+	return mmap_add_dynamic_region_ctx(ctx, mm);
+}
+
 /*
  * Removes the region with given base Virtual Address and size from the given
  * context.