tools/testing/nvdimm: force nfit_test to depend on instrumented modules

The libnvdimm unit tests will fail when they are run against the
production / in-tree version of libnvdimm.ko or nfit.ko due to
symbols not being mocked per nfit_test's expectation. For example,
nfit_test expects acpi_evaluate_dsm() to be replaced by
__wrap_acpi_evaluate_dsm() to test how acpi_nfit_ctl() responds to
different stimuli.

Create a test-only symbol name that nfit_test links against to cause
module load failures when the wrong module is present.

For example, with this change, attempts to use the wrong module will
report:

    nfit_test: Unknown symbol libnvdimm_test (err 0)
Reported-by: NDave Jiang <dave.jiang@intel.com>
Reported-by: NVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

tools/testing/nvdimm/Kbuild

@@ -37,10 +37,12 @@ obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
 
 nfit-y := $(ACPI_SRC)/core.o
 nfit-$(CONFIG_X86_MCE) += $(ACPI_SRC)/mce.o
+nfit-y += acpi_nfit_test.o
 nfit-y += config_check.o
 
 nd_pmem-y := $(NVDIMM_SRC)/pmem.o
 nd_pmem-y += pmem-dax.o
+nd_pmem-y += pmem_test.o
 nd_pmem-y += config_check.o
 
 nd_btt-y := $(NVDIMM_SRC)/btt.o
@@ -57,6 +59,7 @@ dax-y += config_check.o
 
 device_dax-y := $(DAX_SRC)/device.o
 device_dax-y += dax-dev.o
+device_dax-y += device_dax_test.o
 device_dax-y += config_check.o
 
 dax_pmem-y := $(DAX_SRC)/pmem.o
@@ -75,6 +78,7 @@ libnvdimm-$(CONFIG_ND_CLAIM) += $(NVDIMM_SRC)/claim.o
 libnvdimm-$(CONFIG_BTT) += $(NVDIMM_SRC)/btt_devs.o
 libnvdimm-$(CONFIG_NVDIMM_PFN) += $(NVDIMM_SRC)/pfn_devs.o
 libnvdimm-$(CONFIG_NVDIMM_DAX) += $(NVDIMM_SRC)/dax_devs.o
+libnvdimm-y += libnvdimm_test.o
 libnvdimm-y += config_check.o
 
 obj-m += test/

tools/testing/nvdimm/acpi_nfit_test.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright(c) 2018 Intel Corporation. All rights reserved.
+
+#include <linux/module.h>
+#include <linux/printk.h>
+#include "watermark.h"
+
+nfit_test_watermark(acpi_nfit);

tools/testing/nvdimm/device_dax_test.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright(c) 2018 Intel Corporation. All rights reserved.
+
+#include <linux/module.h>
+#include <linux/printk.h>
+#include "watermark.h"
+
+nfit_test_watermark(device_dax);

tools/testing/nvdimm/libnvdimm_test.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright(c) 2018 Intel Corporation. All rights reserved.
+
+#include <linux/module.h>
+#include <linux/printk.h>
+#include "watermark.h"
+
+nfit_test_watermark(libnvdimm);

tools/testing/nvdimm/pmem_test.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright(c) 2018 Intel Corporation. All rights reserved.
+
+#include <linux/module.h>
+#include <linux/printk.h>
+#include "watermark.h"
+
+nfit_test_watermark(pmem);

tools/testing/nvdimm/test/nfit.c

@@ -27,6 +27,7 @@
 #include <nfit.h>
 #include <nd.h>
 #include "nfit_test.h"
+#include "../watermark.h"
 
 /*
  * Generate an NFIT table to describe the following topology:
@@ -2545,6 +2546,11 @@ static __init int nfit_test_init(void)
 {
 	int rc, i;
 
+	pmem_test();
+	libnvdimm_test();
+	acpi_nfit_test();
+	device_dax_test();
+
 	nfit_test_setup(nfit_test_lookup, nfit_test_evaluate_dsm);
 
 	nfit_wq = create_singlethread_workqueue("nfit");

tools/testing/nvdimm/watermark.h

+// SPDX-License-Identifier: GPL-2.0
+// Copyright(c) 2018 Intel Corporation. All rights reserved.
+#ifndef _TEST_NVDIMM_WATERMARK_H_
+#define _TEST_NVDIMM_WATERMARK_H_
+int pmem_test(void);
+int libnvdimm_test(void);
+int acpi_nfit_test(void);
+int device_dax_test(void);
+
+/*
+ * dummy routine for nfit_test to validate it is linking to the properly
+ * mocked module and not the standard one from the base tree.
+ */
+#define nfit_test_watermark(x)				\
+int x##_test(void)					\
+{							\
+	pr_debug("%s for nfit_test\n", KBUILD_MODNAME);	\
+	return 0;					\
+}							\
+EXPORT_SYMBOL(x##_test)
+#endif /* _TEST_NVDIMM_WATERMARK_H_ */