memblock tests: Add memblock_alloc_try_nid tests for top down

Add tests for memblock_alloc_try_nid for top down allocation direction.
As the definition of this function is pretty close to the core
memblock_alloc_range_nid, the test cases implemented here cover most of
the code paths related to the memory allocations.

The tested scenarios are:
  - Region can be allocated within the requested range (both with aligned
    and misaligned boundaries)
  - Region can be allocated between two already existing entries
  - Not enough space between already reserved regions
  - Memory range is too narrow but memory can be allocated before
    the maximum address
  - Edge cases:
      + Minimum address is below memblock_start_of_DRAM()
      + Maximum address is above memblock_end_of_DRAM()

Add checks for both allocation directions:
  - Region starts at the min_addr and ends at max_addr
  - Maximum address is too close to the beginning of the available
    memory
  - Memory at the range boundaries is reserved but there is enough space
    to allocate a new region
Signed-off-by: Karolina Drobnik <karolinadrobnik@gmail.com>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/d6c282e0f9f62c15bf74c216214604764232d637.1646055639.git.karolinadrobnik@gmail.com

tools/testing/memblock/Makefile

@@ -6,8 +6,8 @@ CFLAGS += -I. -I../../include -Wall -O2 -fsanitize=address \
 	  -fsanitize=undefined -D CONFIG_PHYS_ADDR_T_64BIT
 LDFLAGS += -fsanitize=address -fsanitize=undefined
 TARGETS = main
-TEST_OFILES = tests/alloc_helpers_api.o tests/alloc_api.o tests/basic_api.o \
-	      tests/common.o
+TEST_OFILES = tests/alloc_nid_api.o tests/alloc_helpers_api.o tests/alloc_api.o \
+		  tests/basic_api.o tests/common.o
 DEP_OFILES = memblock.o lib/slab.o mmzone.o slab.o
 OFILES = main.o $(DEP_OFILES) $(TEST_OFILES)
 EXTR_SRC = ../../../mm/memblock.c

tools/testing/memblock/main.c

@@ -2,12 +2,14 @@
 #include "tests/basic_api.h"
 #include "tests/alloc_api.h"
 #include "tests/alloc_helpers_api.h"
+#include "tests/alloc_nid_api.h"
 
 int main(int argc, char **argv)
 {
 	memblock_basic_checks();
 	memblock_alloc_checks();
 	memblock_alloc_helpers_checks();
+	memblock_alloc_nid_checks();
 
 	return 0;
 }

tools/testing/memblock/tests/alloc_nid_api.h

+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _MEMBLOCK_ALLOC_NID_H
+#define _MEMBLOCK_ALLOC_NID_H
+
+#include "common.h"
+
+int memblock_alloc_nid_checks(void);
+
+#endif