tests/chip: Add non-aligned write within a region unit-test

A written region that is sized below that of the erasure granularity
can result in a incorrectly read region that does not include prior
content within the region before the write op. This was dealt with
in ChromeOS downstream by expanding out the read to match the erase
granularity however does not seem to impact upstream. Add a unit-test
to avoid regression as this is important behaviour to cover.

Change-Id: Id3ce5cd1936f0f348d34a6c77cee15e27a5c353f
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/71659
Reviewed-by: Sam McNally <sammc@google.com>
Reviewed-by: Evan Benn <evanbenn@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

tests/chip.c

@@ -418,6 +418,97 @@ void write_chip_with_dummyflasher_test_success(void **state)
 	free(newcontents);
 }
 
+void write_nonaligned_region_with_dummyflasher_test_success(void **state)
+{
+	(void) state; /* unused */
+
+	static struct io_mock_fallback_open_state data = {
+		.noc	= 0,
+		.paths	= { NULL },
+	};
+	const struct io_mock chip_io = {
+		.fallback_open_state = &data,
+	};
+
+	struct flashrom_flashctx flashctx = { 0 };
+	struct flashrom_layout *layout;
+	struct flashchip mock_chip = chip_W25Q128_V;
+	const uint32_t mock_chip_size = mock_chip.total_size * KiB;
+	/*
+	 * Dummyflasher is capable to emulate W25Q128.V, so we ask it to do this.
+	 * Nothing to mock, dummy is taking care of this already.
+	 */
+	char *param_dup = strdup("bus=spi,emulate=W25Q128FV");
+
+	/* FIXME: MOCK_CHIP_CONTENT is buggy within setup_chip, it should also
+	 * not be either 0x00 or 0xFF as those are specific values related to
+	 * either a erased chip or zero'ed heap thus ambigous.
+	 */
+#define MOCK_CHIP_SUBREGION_CONTENTS 0xCC
+	/**
+	 * Step 0 - Prepare newcontents as contiguous sample data bytes as follows:
+	 * {MOCK_CHIP_SUBREGION_CONTENTS, [..]}.
+	 */
+	uint8_t *newcontents = calloc(1, mock_chip_size);
+	assert_non_null(newcontents);
+	memset(newcontents, MOCK_CHIP_SUBREGION_CONTENTS, mock_chip_size);
+
+	setup_chip(&flashctx, &layout, &mock_chip, param_dup, &chip_io);
+	/* Expect to verify only the non-aligned write operation within the region. */
+	flashrom_flag_set(&flashctx, FLASHROM_FLAG_VERIFY_AFTER_WRITE, true);
+	flashrom_flag_set(&flashctx, FLASHROM_FLAG_VERIFY_WHOLE_CHIP, false);
+
+	/**
+	 * Prepare mock chip content and release setup_chip() layout for our
+	 * custom ones.
+	 */
+	assert_int_equal(0, flashrom_image_write(&flashctx, newcontents, mock_chip_size, NULL));
+	flashrom_layout_release(layout);
+
+	/**
+	 * Create region smaller than erase granularity of chip.
+	 */
+	printf("Creating custom region layout... ");
+	assert_int_equal(0, flashrom_layout_new(&layout));
+	printf("Adding and including region0... ");
+	assert_int_equal(0, flashrom_layout_add_region(layout, 0, (1 * KiB), "region0"));
+	assert_int_equal(0, flashrom_layout_include_region(layout, "region0"));
+	flashrom_layout_set(&flashctx, layout);
+	printf("Subregion layout configuration done.\n");
+
+	/**
+	 * Step 1 - Modify newcontents as non-contiguous sample data bytes as follows:
+	 * 0xAA 0xAA {MOCK_CHIP_SUBREGION_CONTENTS}, [..]}.
+	 */
+	printf("Subregion chip write op..\n");
+	memset(newcontents, 0xAA, 2);
+	assert_int_equal(0, flashrom_image_write(&flashctx, newcontents, mock_chip_size, NULL));
+	printf("Subregion chip write op done.\n");
+
+	/**
+	 * FIXME: A 'NULL' layout should indicate a default layout however this
+	 * causes a crash for a unknown reason. For now prepare a new default
+	 * layout of the entire chip. flashrom_layout_set(&flashctx, NULL); // use default layout.
+	 */
+	flashrom_layout_release(layout);
+	assert_int_equal(0, flashrom_layout_new(&layout));
+	assert_int_equal(0, flashrom_layout_add_region(layout, 0, mock_chip_size - 1, "entire"));
+	assert_int_equal(0, flashrom_layout_include_region(layout, "entire"));
+	flashrom_layout_set(&flashctx, layout);
+
+	/**
+	 * Expect a verification pass that the previous content within the region, however
+	 * outside the region write length, is untouched.
+	 */
+	printf("Entire chip verify op..\n");
+	assert_int_equal(0, flashrom_image_verify(&flashctx, newcontents, mock_chip_size));
+	printf("Entire chip verify op done.\n");
+
+	teardown(&layout);
+	free(param_dup);
+	free(newcontents);
+}
+
 static size_t verify_chip_fread(void *state, void *buf, size_t size, size_t len, FILE *fp)
 {
 	/*

tests/tests.c

@@ -480,6 +480,7 @@ int main(int argc, char *argv[])
 		cmocka_unit_test(read_chip_with_dummyflasher_test_success),
 		cmocka_unit_test(write_chip_test_success),
 		cmocka_unit_test(write_chip_with_dummyflasher_test_success),
+		cmocka_unit_test(write_nonaligned_region_with_dummyflasher_test_success),
 		cmocka_unit_test(verify_chip_test_success),
 		cmocka_unit_test(verify_chip_with_dummyflasher_test_success),
 	};

tests/tests.h

@@ -80,6 +80,7 @@ void read_chip_test_success(void **state);
 void read_chip_with_dummyflasher_test_success(void **state);
 void write_chip_test_success(void **state);
 void write_chip_with_dummyflasher_test_success(void **state);
+void write_nonaligned_region_with_dummyflasher_test_success(void **state);
 void verify_chip_test_success(void **state);
 void verify_chip_with_dummyflasher_test_success(void **state);