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alistair23-linux/tools/testing/nvdimm/test/nfit_test.h

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/* SPDX-License-Identifier: GPL-2.0-only */
tools/testing/nvdimm: libnvdimm unit test infrastructure 'libnvdimm' is the first driver sub-system in the kernel to implement mocking for unit test coverage. The nfit_test module gets built as an external module and arranges for external module replacements of nfit, libnvdimm, nd_pmem, and nd_blk. These replacements use the linker --wrap option to redirect calls to ioremap() + request_mem_region() to custom defined unit test resources. The end result is a fully functional nvdimm_bus, as far as userspace is concerned, but with the capability to perform otherwise destructive tests on emulated resources. Q: Why not use QEMU for this emulation? QEMU is not suitable for unit testing. QEMU's role is to faithfully emulate the platform. A unit test's role is to unfaithfully implement the platform with the goal of triggering bugs in the corners of the sub-system implementation. As bugs are discovered in platforms, or the sub-system itself, the unit tests are extended to backstop a fix with a reproducer unit test. Another problem with QEMU is that it would require coordination of 3 software projects instead of 2 (kernel + libndctl [1]) to maintain and execute the tests. The chances for bit rot and the difficulty of getting the tests running goes up non-linearly the more components involved. Q: Why submit this to the kernel tree instead of external modules in libndctl? Simple, to alleviate the same risk that out-of-tree external modules face. Updates to drivers/nvdimm/ can be immediately evaluated to see if they have any impact on tools/testing/nvdimm/. Q: What are the negative implications of merging this? It is a unique maintenance burden because the purpose of mocking an interface to enable a unit test is to purposefully short circuit the semantics of a routine to enable testing. For example __wrap_ioremap_cache() fakes the pmem driver into "ioremap()'ing" a test resource buffer allocated by dma_alloc_coherent(). The future maintenance burden hits when someone changes the semantics of ioremap_cache() and wonders what the implications are for the unit test. [1]: https://github.com/pmem/ndctl Cc: <linux-acpi@vger.kernel.org> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-17 15:23:32 -06:00
/*
* Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
*/
#ifndef __NFIT_TEST_H__
#define __NFIT_TEST_H__
#include <linux/list.h>
#include <linux/uuid.h>
#include <linux/ioport.h>
#include <linux/spinlock_types.h>
struct nfit_test_request {
struct list_head list;
struct resource res;
};
tools/testing/nvdimm: libnvdimm unit test infrastructure 'libnvdimm' is the first driver sub-system in the kernel to implement mocking for unit test coverage. The nfit_test module gets built as an external module and arranges for external module replacements of nfit, libnvdimm, nd_pmem, and nd_blk. These replacements use the linker --wrap option to redirect calls to ioremap() + request_mem_region() to custom defined unit test resources. The end result is a fully functional nvdimm_bus, as far as userspace is concerned, but with the capability to perform otherwise destructive tests on emulated resources. Q: Why not use QEMU for this emulation? QEMU is not suitable for unit testing. QEMU's role is to faithfully emulate the platform. A unit test's role is to unfaithfully implement the platform with the goal of triggering bugs in the corners of the sub-system implementation. As bugs are discovered in platforms, or the sub-system itself, the unit tests are extended to backstop a fix with a reproducer unit test. Another problem with QEMU is that it would require coordination of 3 software projects instead of 2 (kernel + libndctl [1]) to maintain and execute the tests. The chances for bit rot and the difficulty of getting the tests running goes up non-linearly the more components involved. Q: Why submit this to the kernel tree instead of external modules in libndctl? Simple, to alleviate the same risk that out-of-tree external modules face. Updates to drivers/nvdimm/ can be immediately evaluated to see if they have any impact on tools/testing/nvdimm/. Q: What are the negative implications of merging this? It is a unique maintenance burden because the purpose of mocking an interface to enable a unit test is to purposefully short circuit the semantics of a routine to enable testing. For example __wrap_ioremap_cache() fakes the pmem driver into "ioremap()'ing" a test resource buffer allocated by dma_alloc_coherent(). The future maintenance burden hits when someone changes the semantics of ioremap_cache() and wonders what the implications are for the unit test. [1]: https://github.com/pmem/ndctl Cc: <linux-acpi@vger.kernel.org> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-17 15:23:32 -06:00
struct nfit_test_resource {
struct list_head requests;
tools/testing/nvdimm: libnvdimm unit test infrastructure 'libnvdimm' is the first driver sub-system in the kernel to implement mocking for unit test coverage. The nfit_test module gets built as an external module and arranges for external module replacements of nfit, libnvdimm, nd_pmem, and nd_blk. These replacements use the linker --wrap option to redirect calls to ioremap() + request_mem_region() to custom defined unit test resources. The end result is a fully functional nvdimm_bus, as far as userspace is concerned, but with the capability to perform otherwise destructive tests on emulated resources. Q: Why not use QEMU for this emulation? QEMU is not suitable for unit testing. QEMU's role is to faithfully emulate the platform. A unit test's role is to unfaithfully implement the platform with the goal of triggering bugs in the corners of the sub-system implementation. As bugs are discovered in platforms, or the sub-system itself, the unit tests are extended to backstop a fix with a reproducer unit test. Another problem with QEMU is that it would require coordination of 3 software projects instead of 2 (kernel + libndctl [1]) to maintain and execute the tests. The chances for bit rot and the difficulty of getting the tests running goes up non-linearly the more components involved. Q: Why submit this to the kernel tree instead of external modules in libndctl? Simple, to alleviate the same risk that out-of-tree external modules face. Updates to drivers/nvdimm/ can be immediately evaluated to see if they have any impact on tools/testing/nvdimm/. Q: What are the negative implications of merging this? It is a unique maintenance burden because the purpose of mocking an interface to enable a unit test is to purposefully short circuit the semantics of a routine to enable testing. For example __wrap_ioremap_cache() fakes the pmem driver into "ioremap()'ing" a test resource buffer allocated by dma_alloc_coherent(). The future maintenance burden hits when someone changes the semantics of ioremap_cache() and wonders what the implications are for the unit test. [1]: https://github.com/pmem/ndctl Cc: <linux-acpi@vger.kernel.org> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-17 15:23:32 -06:00
struct list_head list;
struct resource res;
tools/testing/nvdimm: libnvdimm unit test infrastructure 'libnvdimm' is the first driver sub-system in the kernel to implement mocking for unit test coverage. The nfit_test module gets built as an external module and arranges for external module replacements of nfit, libnvdimm, nd_pmem, and nd_blk. These replacements use the linker --wrap option to redirect calls to ioremap() + request_mem_region() to custom defined unit test resources. The end result is a fully functional nvdimm_bus, as far as userspace is concerned, but with the capability to perform otherwise destructive tests on emulated resources. Q: Why not use QEMU for this emulation? QEMU is not suitable for unit testing. QEMU's role is to faithfully emulate the platform. A unit test's role is to unfaithfully implement the platform with the goal of triggering bugs in the corners of the sub-system implementation. As bugs are discovered in platforms, or the sub-system itself, the unit tests are extended to backstop a fix with a reproducer unit test. Another problem with QEMU is that it would require coordination of 3 software projects instead of 2 (kernel + libndctl [1]) to maintain and execute the tests. The chances for bit rot and the difficulty of getting the tests running goes up non-linearly the more components involved. Q: Why submit this to the kernel tree instead of external modules in libndctl? Simple, to alleviate the same risk that out-of-tree external modules face. Updates to drivers/nvdimm/ can be immediately evaluated to see if they have any impact on tools/testing/nvdimm/. Q: What are the negative implications of merging this? It is a unique maintenance burden because the purpose of mocking an interface to enable a unit test is to purposefully short circuit the semantics of a routine to enable testing. For example __wrap_ioremap_cache() fakes the pmem driver into "ioremap()'ing" a test resource buffer allocated by dma_alloc_coherent(). The future maintenance burden hits when someone changes the semantics of ioremap_cache() and wonders what the implications are for the unit test. [1]: https://github.com/pmem/ndctl Cc: <linux-acpi@vger.kernel.org> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-17 15:23:32 -06:00
struct device *dev;
spinlock_t lock;
int req_count;
tools/testing/nvdimm: libnvdimm unit test infrastructure 'libnvdimm' is the first driver sub-system in the kernel to implement mocking for unit test coverage. The nfit_test module gets built as an external module and arranges for external module replacements of nfit, libnvdimm, nd_pmem, and nd_blk. These replacements use the linker --wrap option to redirect calls to ioremap() + request_mem_region() to custom defined unit test resources. The end result is a fully functional nvdimm_bus, as far as userspace is concerned, but with the capability to perform otherwise destructive tests on emulated resources. Q: Why not use QEMU for this emulation? QEMU is not suitable for unit testing. QEMU's role is to faithfully emulate the platform. A unit test's role is to unfaithfully implement the platform with the goal of triggering bugs in the corners of the sub-system implementation. As bugs are discovered in platforms, or the sub-system itself, the unit tests are extended to backstop a fix with a reproducer unit test. Another problem with QEMU is that it would require coordination of 3 software projects instead of 2 (kernel + libndctl [1]) to maintain and execute the tests. The chances for bit rot and the difficulty of getting the tests running goes up non-linearly the more components involved. Q: Why submit this to the kernel tree instead of external modules in libndctl? Simple, to alleviate the same risk that out-of-tree external modules face. Updates to drivers/nvdimm/ can be immediately evaluated to see if they have any impact on tools/testing/nvdimm/. Q: What are the negative implications of merging this? It is a unique maintenance burden because the purpose of mocking an interface to enable a unit test is to purposefully short circuit the semantics of a routine to enable testing. For example __wrap_ioremap_cache() fakes the pmem driver into "ioremap()'ing" a test resource buffer allocated by dma_alloc_coherent(). The future maintenance burden hits when someone changes the semantics of ioremap_cache() and wonders what the implications are for the unit test. [1]: https://github.com/pmem/ndctl Cc: <linux-acpi@vger.kernel.org> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-17 15:23:32 -06:00
void *buf;
};
#define ND_TRANSLATE_SPA_STATUS_INVALID_SPA 2
#define NFIT_ARS_INJECT_INVALID 2
enum err_inj_options {
ND_ARS_ERR_INJ_OPT_NOTIFY = 0,
};
/* nfit commands */
enum nfit_cmd_num {
NFIT_CMD_TRANSLATE_SPA = 5,
NFIT_CMD_ARS_INJECT_SET = 7,
NFIT_CMD_ARS_INJECT_CLEAR = 8,
NFIT_CMD_ARS_INJECT_GET = 9,
};
struct nd_cmd_translate_spa {
__u64 spa;
__u32 status;
__u8 flags;
__u8 _reserved[3];
__u64 translate_length;
__u32 num_nvdimms;
struct nd_nvdimm_device {
__u32 nfit_device_handle;
__u32 _reserved;
__u64 dpa;
} __packed devices[0];
} __packed;
struct nd_cmd_ars_err_inj {
__u64 err_inj_spa_range_base;
__u64 err_inj_spa_range_length;
__u8 err_inj_options;
__u32 status;
} __packed;
struct nd_cmd_ars_err_inj_clr {
__u64 err_inj_clr_spa_range_base;
__u64 err_inj_clr_spa_range_length;
__u32 status;
} __packed;
struct nd_cmd_ars_err_inj_stat {
__u32 status;
__u32 inj_err_rec_count;
struct nd_error_stat_query_record {
__u64 err_inj_stat_spa_range_base;
__u64 err_inj_stat_spa_range_length;
} __packed record[0];
} __packed;
#define ND_INTEL_SMART 1
#define ND_INTEL_SMART_THRESHOLD 2
#define ND_INTEL_ENABLE_LSS_STATUS 10
#define ND_INTEL_FW_GET_INFO 12
#define ND_INTEL_FW_START_UPDATE 13
#define ND_INTEL_FW_SEND_DATA 14
#define ND_INTEL_FW_FINISH_UPDATE 15
#define ND_INTEL_FW_FINISH_QUERY 16
#define ND_INTEL_SMART_SET_THRESHOLD 17
#define ND_INTEL_SMART_INJECT 18
#define ND_INTEL_SMART_HEALTH_VALID (1 << 0)
#define ND_INTEL_SMART_SPARES_VALID (1 << 1)
#define ND_INTEL_SMART_USED_VALID (1 << 2)
#define ND_INTEL_SMART_MTEMP_VALID (1 << 3)
#define ND_INTEL_SMART_CTEMP_VALID (1 << 4)
#define ND_INTEL_SMART_SHUTDOWN_COUNT_VALID (1 << 5)
#define ND_INTEL_SMART_AIT_STATUS_VALID (1 << 6)
#define ND_INTEL_SMART_PTEMP_VALID (1 << 7)
#define ND_INTEL_SMART_ALARM_VALID (1 << 9)
#define ND_INTEL_SMART_SHUTDOWN_VALID (1 << 10)
#define ND_INTEL_SMART_VENDOR_VALID (1 << 11)
#define ND_INTEL_SMART_SPARE_TRIP (1 << 0)
#define ND_INTEL_SMART_TEMP_TRIP (1 << 1)
#define ND_INTEL_SMART_CTEMP_TRIP (1 << 2)
#define ND_INTEL_SMART_NON_CRITICAL_HEALTH (1 << 0)
#define ND_INTEL_SMART_CRITICAL_HEALTH (1 << 1)
#define ND_INTEL_SMART_FATAL_HEALTH (1 << 2)
#define ND_INTEL_SMART_INJECT_MTEMP (1 << 0)
#define ND_INTEL_SMART_INJECT_SPARE (1 << 1)
#define ND_INTEL_SMART_INJECT_FATAL (1 << 2)
#define ND_INTEL_SMART_INJECT_SHUTDOWN (1 << 3)
struct nd_intel_smart_threshold {
__u32 status;
union {
struct {
__u16 alarm_control;
__u8 spares;
__u16 media_temperature;
__u16 ctrl_temperature;
__u8 reserved[1];
} __packed;
__u8 data[8];
};
} __packed;
struct nd_intel_smart_set_threshold {
__u16 alarm_control;
__u8 spares;
__u16 media_temperature;
__u16 ctrl_temperature;
__u32 status;
} __packed;
struct nd_intel_smart_inject {
__u64 flags;
__u8 mtemp_enable;
__u16 media_temperature;
__u8 spare_enable;
__u8 spares;
__u8 fatal_enable;
__u8 unsafe_shutdown_enable;
__u32 status;
} __packed;
#define INTEL_FW_STORAGE_SIZE 0x100000
#define INTEL_FW_MAX_SEND_LEN 0xFFEC
#define INTEL_FW_QUERY_INTERVAL 250000
#define INTEL_FW_QUERY_MAX_TIME 3000000
#define INTEL_FW_FIS_VERSION 0x0105
#define INTEL_FW_FAKE_VERSION 0xffffffffabcd
enum intel_fw_update_state {
FW_STATE_NEW = 0,
FW_STATE_IN_PROGRESS,
FW_STATE_VERIFY,
FW_STATE_UPDATED,
};
struct nd_intel_fw_info {
__u32 status;
__u32 storage_size;
__u32 max_send_len;
__u32 query_interval;
__u32 max_query_time;
__u8 update_cap;
__u8 reserved[3];
__u32 fis_version;
__u64 run_version;
__u64 updated_version;
} __packed;
struct nd_intel_fw_start {
__u32 status;
__u32 context;
} __packed;
/* this one has the output first because the variable input data size */
struct nd_intel_fw_send_data {
__u32 context;
__u32 offset;
__u32 length;
__u8 data[0];
/* this field is not declared due ot variable data from input */
/* __u32 status; */
} __packed;
struct nd_intel_fw_finish_update {
__u8 ctrl_flags;
__u8 reserved[3];
__u32 context;
__u32 status;
} __packed;
struct nd_intel_fw_finish_query {
__u32 context;
__u32 status;
__u64 updated_fw_rev;
} __packed;
struct nd_intel_lss {
__u8 enable;
__u32 status;
} __packed;
union acpi_object;
typedef void *acpi_handle;
tools/testing/nvdimm: libnvdimm unit test infrastructure 'libnvdimm' is the first driver sub-system in the kernel to implement mocking for unit test coverage. The nfit_test module gets built as an external module and arranges for external module replacements of nfit, libnvdimm, nd_pmem, and nd_blk. These replacements use the linker --wrap option to redirect calls to ioremap() + request_mem_region() to custom defined unit test resources. The end result is a fully functional nvdimm_bus, as far as userspace is concerned, but with the capability to perform otherwise destructive tests on emulated resources. Q: Why not use QEMU for this emulation? QEMU is not suitable for unit testing. QEMU's role is to faithfully emulate the platform. A unit test's role is to unfaithfully implement the platform with the goal of triggering bugs in the corners of the sub-system implementation. As bugs are discovered in platforms, or the sub-system itself, the unit tests are extended to backstop a fix with a reproducer unit test. Another problem with QEMU is that it would require coordination of 3 software projects instead of 2 (kernel + libndctl [1]) to maintain and execute the tests. The chances for bit rot and the difficulty of getting the tests running goes up non-linearly the more components involved. Q: Why submit this to the kernel tree instead of external modules in libndctl? Simple, to alleviate the same risk that out-of-tree external modules face. Updates to drivers/nvdimm/ can be immediately evaluated to see if they have any impact on tools/testing/nvdimm/. Q: What are the negative implications of merging this? It is a unique maintenance burden because the purpose of mocking an interface to enable a unit test is to purposefully short circuit the semantics of a routine to enable testing. For example __wrap_ioremap_cache() fakes the pmem driver into "ioremap()'ing" a test resource buffer allocated by dma_alloc_coherent(). The future maintenance burden hits when someone changes the semantics of ioremap_cache() and wonders what the implications are for the unit test. [1]: https://github.com/pmem/ndctl Cc: <linux-acpi@vger.kernel.org> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-17 15:23:32 -06:00
typedef struct nfit_test_resource *(*nfit_test_lookup_fn)(resource_size_t);
typedef union acpi_object *(*nfit_test_evaluate_dsm_fn)(acpi_handle handle,
const guid_t *guid, u64 rev, u64 func,
union acpi_object *argv4);
tools/testing/nvdimm: libnvdimm unit test infrastructure 'libnvdimm' is the first driver sub-system in the kernel to implement mocking for unit test coverage. The nfit_test module gets built as an external module and arranges for external module replacements of nfit, libnvdimm, nd_pmem, and nd_blk. These replacements use the linker --wrap option to redirect calls to ioremap() + request_mem_region() to custom defined unit test resources. The end result is a fully functional nvdimm_bus, as far as userspace is concerned, but with the capability to perform otherwise destructive tests on emulated resources. Q: Why not use QEMU for this emulation? QEMU is not suitable for unit testing. QEMU's role is to faithfully emulate the platform. A unit test's role is to unfaithfully implement the platform with the goal of triggering bugs in the corners of the sub-system implementation. As bugs are discovered in platforms, or the sub-system itself, the unit tests are extended to backstop a fix with a reproducer unit test. Another problem with QEMU is that it would require coordination of 3 software projects instead of 2 (kernel + libndctl [1]) to maintain and execute the tests. The chances for bit rot and the difficulty of getting the tests running goes up non-linearly the more components involved. Q: Why submit this to the kernel tree instead of external modules in libndctl? Simple, to alleviate the same risk that out-of-tree external modules face. Updates to drivers/nvdimm/ can be immediately evaluated to see if they have any impact on tools/testing/nvdimm/. Q: What are the negative implications of merging this? It is a unique maintenance burden because the purpose of mocking an interface to enable a unit test is to purposefully short circuit the semantics of a routine to enable testing. For example __wrap_ioremap_cache() fakes the pmem driver into "ioremap()'ing" a test resource buffer allocated by dma_alloc_coherent(). The future maintenance burden hits when someone changes the semantics of ioremap_cache() and wonders what the implications are for the unit test. [1]: https://github.com/pmem/ndctl Cc: <linux-acpi@vger.kernel.org> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-17 15:23:32 -06:00
void __iomem *__wrap_ioremap_nocache(resource_size_t offset,
unsigned long size);
void __wrap_iounmap(volatile void __iomem *addr);
void nfit_test_setup(nfit_test_lookup_fn lookup,
nfit_test_evaluate_dsm_fn evaluate);
tools/testing/nvdimm: libnvdimm unit test infrastructure 'libnvdimm' is the first driver sub-system in the kernel to implement mocking for unit test coverage. The nfit_test module gets built as an external module and arranges for external module replacements of nfit, libnvdimm, nd_pmem, and nd_blk. These replacements use the linker --wrap option to redirect calls to ioremap() + request_mem_region() to custom defined unit test resources. The end result is a fully functional nvdimm_bus, as far as userspace is concerned, but with the capability to perform otherwise destructive tests on emulated resources. Q: Why not use QEMU for this emulation? QEMU is not suitable for unit testing. QEMU's role is to faithfully emulate the platform. A unit test's role is to unfaithfully implement the platform with the goal of triggering bugs in the corners of the sub-system implementation. As bugs are discovered in platforms, or the sub-system itself, the unit tests are extended to backstop a fix with a reproducer unit test. Another problem with QEMU is that it would require coordination of 3 software projects instead of 2 (kernel + libndctl [1]) to maintain and execute the tests. The chances for bit rot and the difficulty of getting the tests running goes up non-linearly the more components involved. Q: Why submit this to the kernel tree instead of external modules in libndctl? Simple, to alleviate the same risk that out-of-tree external modules face. Updates to drivers/nvdimm/ can be immediately evaluated to see if they have any impact on tools/testing/nvdimm/. Q: What are the negative implications of merging this? It is a unique maintenance burden because the purpose of mocking an interface to enable a unit test is to purposefully short circuit the semantics of a routine to enable testing. For example __wrap_ioremap_cache() fakes the pmem driver into "ioremap()'ing" a test resource buffer allocated by dma_alloc_coherent(). The future maintenance burden hits when someone changes the semantics of ioremap_cache() and wonders what the implications are for the unit test. [1]: https://github.com/pmem/ndctl Cc: <linux-acpi@vger.kernel.org> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-17 15:23:32 -06:00
void nfit_test_teardown(void);
struct nfit_test_resource *get_nfit_res(resource_size_t resource);
tools/testing/nvdimm: libnvdimm unit test infrastructure 'libnvdimm' is the first driver sub-system in the kernel to implement mocking for unit test coverage. The nfit_test module gets built as an external module and arranges for external module replacements of nfit, libnvdimm, nd_pmem, and nd_blk. These replacements use the linker --wrap option to redirect calls to ioremap() + request_mem_region() to custom defined unit test resources. The end result is a fully functional nvdimm_bus, as far as userspace is concerned, but with the capability to perform otherwise destructive tests on emulated resources. Q: Why not use QEMU for this emulation? QEMU is not suitable for unit testing. QEMU's role is to faithfully emulate the platform. A unit test's role is to unfaithfully implement the platform with the goal of triggering bugs in the corners of the sub-system implementation. As bugs are discovered in platforms, or the sub-system itself, the unit tests are extended to backstop a fix with a reproducer unit test. Another problem with QEMU is that it would require coordination of 3 software projects instead of 2 (kernel + libndctl [1]) to maintain and execute the tests. The chances for bit rot and the difficulty of getting the tests running goes up non-linearly the more components involved. Q: Why submit this to the kernel tree instead of external modules in libndctl? Simple, to alleviate the same risk that out-of-tree external modules face. Updates to drivers/nvdimm/ can be immediately evaluated to see if they have any impact on tools/testing/nvdimm/. Q: What are the negative implications of merging this? It is a unique maintenance burden because the purpose of mocking an interface to enable a unit test is to purposefully short circuit the semantics of a routine to enable testing. For example __wrap_ioremap_cache() fakes the pmem driver into "ioremap()'ing" a test resource buffer allocated by dma_alloc_coherent(). The future maintenance burden hits when someone changes the semantics of ioremap_cache() and wonders what the implications are for the unit test. [1]: https://github.com/pmem/ndctl Cc: <linux-acpi@vger.kernel.org> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-06-17 15:23:32 -06:00
#endif