memblock tests: Add memblock_reserve tests

Add checks for marking a region as reserved in different scenarios:
 - The region does not overlap with existing entries
 - The region overlaps with one of the previous entries: from the top
   (its end address is bigger than the base of the existing region) or
   from the bottom (its base address is smaller than the end address of
   one of the regions)
 - The region is within an already defined region
 - The same region is marked as reserved twice
Signed-off-by: Karolina Drobnik <karolinadrobnik@gmail.com>
Signed-off-by: Mike Rapoport <rppt@kernel.org>
Link: https://lore.kernel.org/r/cac867d2b6c17e53d9e977b5d6cd88cc4e9453b6.1643796665.git.karolinadrobnik@gmail.com

tools/testing/memblock/tests/basic_api.c

@@ -239,9 +239,226 @@ static int memblock_add_checks(void)
 	return 0;
 }
 
+ /*
+  * A simple test that marks a memory block of a specified base address
+  * and size as reserved and to the collection of reserved memory regions
+  * (memblock.reserved). It checks if a new entry was created and if region
+  * counter and total memory size were correctly updated.
+  */
+static int memblock_reserve_simple_check(void)
+{
+	struct memblock_region *rgn;
+
+	rgn =  &memblock.reserved.regions[0];
+
+	struct region r = {
+		.base = SZ_2G,
+		.size = SZ_128M
+	};
+
+	reset_memblock();
+	memblock_reserve(r.base, r.size);
+
+	assert(rgn->base == r.base);
+	assert(rgn->size == r.size);
+
+	return 0;
+}
+
+/*
+ * A test that tries to mark two memory blocks that don't overlap as reserved
+ * and checks if two entries were correctly added to the collection of reserved
+ * memory regions (memblock.reserved) and if this change was reflected in
+ * memblock.reserved's total size and region counter.
+ */
+static int memblock_reserve_disjoint_check(void)
+{
+	struct memblock_region *rgn1, *rgn2;
+
+	rgn1 = &memblock.reserved.regions[0];
+	rgn2 = &memblock.reserved.regions[1];
+
+	struct region r1 = {
+		.base = SZ_256M,
+		.size = SZ_16M
+	};
+	struct region r2 = {
+		.base = SZ_512M,
+		.size = SZ_512M
+	};
+
+	reset_memblock();
+	memblock_reserve(r1.base, r1.size);
+	memblock_reserve(r2.base, r2.size);
+
+	assert(rgn1->base == r1.base);
+	assert(rgn1->size == r1.size);
+
+	assert(rgn2->base == r2.base);
+	assert(rgn2->size == r2.size);
+
+	assert(memblock.reserved.cnt == 2);
+	assert(memblock.reserved.total_size == r1.size + r2.size);
+
+	return 0;
+}
+
+/*
+ * A test that tries to mark two memory blocks as reserved, where the
+ * second one overlaps with the beginning of the first (that is
+ * r1.base < r2.base + r2.size).
+ * It checks if two entries are merged into one region that starts at r2.base
+ * and has size of two regions minus their intersection. The test also verifies
+ * that memblock can still see only one entry and has a correct total size of
+ * the reserved memory.
+ */
+static int memblock_reserve_overlap_top_check(void)
+{
+	struct memblock_region *rgn;
+	phys_addr_t total_size;
+
+	rgn = &memblock.reserved.regions[0];
+
+	struct region r1 = {
+		.base = SZ_1G,
+		.size = SZ_1G
+	};
+	struct region r2 = {
+		.base = SZ_128M,
+		.size = SZ_1G
+	};
+
+	total_size = (r1.base - r2.base) + r1.size;
+
+	reset_memblock();
+	memblock_reserve(r1.base, r1.size);
+	memblock_reserve(r2.base, r2.size);
+
+	assert(rgn->base == r2.base);
+	assert(rgn->size == total_size);
+
+	assert(memblock.reserved.cnt == 1);
+	assert(memblock.reserved.total_size == total_size);
+
+	return 0;
+}
+
+/*
+ * A test that tries to mark two memory blocks as reserved, where the
+ * second one overlaps with the end of the first entry (that is
+ * r2.base < r1.base + r1.size).
+ * It checks if two entries are merged into one region that starts at r1.base
+ * and has size of two regions minus their intersection. It verifies that
+ * memblock can still see only one entry and has a correct total size of the
+ * reserved memory.
+ */
+static int memblock_reserve_overlap_bottom_check(void)
+{
+	struct memblock_region *rgn;
+	phys_addr_t total_size;
+
+	rgn = &memblock.reserved.regions[0];
+
+	struct region r1 = {
+		.base = SZ_2K,
+		.size = SZ_128K
+	};
+	struct region r2 = {
+		.base = SZ_128K,
+		.size = SZ_128K
+	};
+
+	total_size = (r2.base - r1.base) + r2.size;
+
+	reset_memblock();
+	memblock_reserve(r1.base, r1.size);
+	memblock_reserve(r2.base, r2.size);
+
+	assert(rgn->base == r1.base);
+	assert(rgn->size == total_size);
+
+	assert(memblock.reserved.cnt == 1);
+	assert(memblock.reserved.total_size == total_size);
+
+	return 0;
+}
+
+/*
+ * A test that tries to mark two memory blocks as reserved, where the second
+ * one is within the range of the first entry (that is
+ * (r1.base < r2.base) && (r2.base + r2.size < r1.base + r1.size)).
+ * It checks if two entries are merged into one region that stays the
+ * same. The counter and total size of available memory are expected to not be
+ * updated.
+ */
+static int memblock_reserve_within_check(void)
+{
+	struct memblock_region *rgn;
+
+	rgn = &memblock.reserved.regions[0];
+
+	struct region r1 = {
+		.base = SZ_1M,
+		.size = SZ_8M
+	};
+	struct region r2 = {
+		.base = SZ_2M,
+		.size = SZ_64K
+	};
+
+	reset_memblock();
+	memblock_reserve(r1.base, r1.size);
+	memblock_reserve(r2.base, r2.size);
+
+	assert(rgn->base == r1.base);
+	assert(rgn->size == r1.size);
+
+	assert(memblock.reserved.cnt == 1);
+	assert(memblock.reserved.total_size == r1.size);
+
+	return 0;
+}
+
+/*
+ * A simple test that tries to reserve the same memory block twice.
+ * The region counter and total size of reserved memory are expected to not
+ * be updated.
+ */
+static int memblock_reserve_twice_check(void)
+{
+	struct region r = {
+		.base = SZ_16K,
+		.size = SZ_2M
+	};
+
+	reset_memblock();
+
+	memblock_reserve(r.base, r.size);
+	memblock_reserve(r.base, r.size);
+
+	assert(memblock.reserved.cnt == 1);
+	assert(memblock.reserved.total_size == r.size);
+
+	return 0;
+}
+
+static int memblock_reserve_checks(void)
+{
+	memblock_reserve_simple_check();
+	memblock_reserve_disjoint_check();
+	memblock_reserve_overlap_top_check();
+	memblock_reserve_overlap_bottom_check();
+	memblock_reserve_within_check();
+	memblock_reserve_twice_check();
+
+	return 0;
+}
+
 int memblock_basic_checks(void)
 {
 	memblock_initialization_check();
 	memblock_add_checks();
+	memblock_reserve_checks();
+
 	return 0;
 }