tests: Add lib/stack-test test case

Signed-off-by: Jakub Czapiga <jacz@semihalf.com>
Change-Id: Icf0cceac290618a50ecc4e65f1f9551dbf31bd32
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50305
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Fagerburg <pfagerburg@chromium.org>

tests/lib/Makefile.inc

@@ -13,6 +13,7 @@ tests-y += fmap-test
 tests-y += imd_cbmem-romstage-test
 tests-y += imd_cbmem-ramstage-test
 tests-y += region_file-test
+tests-y += stack-test
 
 string-test-srcs += tests/lib/string-test.c
 string-test-srcs += src/lib/string.c
@@ -71,3 +72,7 @@ imd_cbmem-romstage-test-mocks += cbmem_top_chipset
 region_file-test-srcs += tests/lib/region_file-test.c
 region_file-test-srcs += src/commonlib/region.c
 region_file-test-srcs += tests/stubs/console.c
+
+stack-test-srcs += tests/lib/stack-test.c
+stack-test-srcs += src/lib/stack.c
+stack-test-srcs += tests/stubs/console.c

tests/lib/stack-test.c

@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <tests/test.h>
+#include <lib.h>
+#include <symbols.h>
+
+
+#if CONFIG_STACK_SIZE == 0
+# define STACK_SIZE 0x1000
+#else
+# define STACK_SIZE CONFIG_STACK_SIZE
+#endif
+
+/* Value used for stack initialization. Change if implementation changes. */
+#define STACK_GUARD_VALUE 0xDEADBEEF
+
+__weak extern u8 _stack[];
+__weak extern u8 _estack[];
+TEST_REGION(stack, STACK_SIZE);
+
+
+static void fill_stack(u32 value)
+{
+	u32 *stack = (u32 *)_stack;
+	for (size_t i = 0; i < STACK_SIZE / sizeof(u32); ++i)
+		stack[i] = value;
+}
+
+/* Fill stack region with guard value.  */
+static void clean_stack(void)
+{
+	fill_stack(STACK_GUARD_VALUE);
+}
+
+static int setup_stack_test(void **state)
+{
+	void *top_of_stack = _stack + sizeof(_stack);
+
+	clean_stack();
+	*state = top_of_stack;
+
+	return 0;
+}
+
+static void test_empty_stack(void **state)
+{
+	void *top_of_stack = *state;
+
+	/* Expect success when checking empty stack. */
+	assert_int_equal(0, checkstack(top_of_stack, 0));
+}
+
+static void test_almost_full_stack(void **state)
+{
+	void *top_of_stack = *state;
+	u32 *stack = (u32 *)_stack;
+
+	/* Fill stack with random value except last word */
+	for (size_t i = 1; i < STACK_SIZE / sizeof(u32); ++i)
+		stack[i] = 0xAA11FF44;
+
+	/* Expect success when checking almost-full stack,
+	   because last guard value is present */
+	assert_int_equal(0, checkstack(top_of_stack, 0));
+}
+
+static void test_full_stack(void **state)
+{
+	void *top_of_stack = *state;
+
+	/* Fill stack with value different than stack guard */
+	fill_stack(0x600DB015);
+
+	/* Expect failure when checking full stack as absence of guard value at the end of
+	   the stack indicates stack overrun. */
+	assert_int_equal(-1, checkstack(top_of_stack, 0));
+}
+
+static void test_partialy_filled_stack(void **state)
+{
+	void *top_of_stack = *state;
+	u32 *stack = (u32 *)_stack;
+	size_t i = STACK_SIZE / sizeof(u32) / 2;
+
+	for (; i < STACK_SIZE / sizeof(u32); ++i)
+		stack[i] = 0x4321ABDC + i;
+
+	/* Expect success when checking partially-filled stack,
+	   because only part of stack is filled with non-guard value. */
+	assert_int_equal(0, checkstack(top_of_stack, 0));
+}
+
+static void test_alternately_filled_stack(void **state)
+{
+	void *top_of_stack = *state;
+	u32 *stack = (u32 *)_stack;
+	size_t i;
+
+	for (i = 0; i < STACK_SIZE / sizeof(u32); i += 2)
+		stack[i] = STACK_GUARD_VALUE;
+
+	for (i = 1; i < STACK_SIZE / sizeof(u32); i += 2)
+		stack[i] = 0x42420707;
+
+	assert_int_equal(0, checkstack(top_of_stack, 0));
+}
+
+static void test_incorrectly_initialized_stack(void **state)
+{
+	void *top_of_stack = *state;
+	u32 *stack = (u32 *)_stack;
+
+	/* Remove last stack guard value */
+	stack[0] = 0xFF00FF11;
+
+	/* Expect failure when there is no last stack guard value even if no other value was
+	   changed. */
+	assert_int_equal(-1, checkstack(top_of_stack, 0));
+}
+
+int main(void)
+{
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test_setup(test_empty_stack, setup_stack_test),
+		cmocka_unit_test_setup(test_almost_full_stack, setup_stack_test),
+		cmocka_unit_test_setup(test_full_stack, setup_stack_test),
+		cmocka_unit_test_setup(test_partialy_filled_stack, setup_stack_test),
+		cmocka_unit_test_setup(test_alternately_filled_stack, setup_stack_test),
+		cmocka_unit_test_setup(test_incorrectly_initialized_stack, setup_stack_test),
+	};
+
+	return cmocka_run_group_tests(tests, NULL, NULL);
+}