/* SPDX-License-Identifier: GPL-2.0-only */ /* Copyright(c) 2022 Intel Corporation. */ #ifndef _IFS_H_ #define _IFS_H_ /** * DOC: In-Field Scan * * ============= * In-Field Scan * ============= * * Introduction * ------------ * * In Field Scan (IFS) is a hardware feature to run circuit level tests on * a CPU core to detect problems that are not caught by parity or ECC checks. * Future CPUs will support more than one type of test which will show up * with a new platform-device instance-id. * * * IFS Image * --------- * * Intel provides a firmware file containing the scan tests via * github [#f1]_. Similar to microcode there is a separate file for each * family-model-stepping. IFS Images are not applicable for some test types. * Wherever applicable the sysfs directory would provide a "current_batch" file * (see below) for loading the image. * * * IFS Image Loading * ----------------- * * The driver loads the tests into memory reserved BIOS local to each CPU * socket in a two step process using writes to MSRs to first load the * SHA hashes for the test. Then the tests themselves. Status MSRs provide * feedback on the success/failure of these steps. * * The test files are kept in a fixed location: /lib/firmware/intel/ifs_<n>/ * For e.g if there are 3 test files, they would be named in the following * fashion: * ff-mm-ss-01.scan * ff-mm-ss-02.scan * ff-mm-ss-03.scan * (where ff refers to family, mm indicates model and ss indicates stepping) * * A different test file can be loaded by writing the numerical portion * (e.g 1, 2 or 3 in the above scenario) into the curent_batch file. * To load ff-mm-ss-02.scan, the following command can be used:: * * # echo 2 > /sys/devices/virtual/misc/intel_ifs_<n>/current_batch * * The above file can also be read to know the currently loaded image. * * Running tests * ------------- * * Tests are run by the driver synchronizing execution of all threads on a * core and then writing to the ACTIVATE_SCAN MSR on all threads. Instruction * execution continues when: * * 1) All tests have completed. * 2) Execution was interrupted. * 3) A test detected a problem. * * Note that ALL THREADS ON THE CORE ARE EFFECTIVELY OFFLINE FOR THE * DURATION OF THE TEST. This can be up to 200 milliseconds. If the system * is running latency sensitive applications that cannot tolerate an * interruption of this magnitude, the system administrator must arrange * to migrate those applications to other cores before running a core test. * It may also be necessary to redirect interrupts to other CPUs. * * In all cases reading the corresponding test's STATUS MSR provides details on what * happened. The driver makes the value of this MSR visible to applications * via the "details" file (see below). Interrupted tests may be restarted. * * The IFS driver provides sysfs interfaces via /sys/devices/virtual/misc/intel_ifs_<n>/ * to control execution: * * Test a specific core:: * * # echo <cpu#> > /sys/devices/virtual/misc/intel_ifs_<n>/run_test * * when HT is enabled any of the sibling cpu# can be specified to test * its corresponding physical core. Since the tests are per physical core, * the result of testing any thread is same. All siblings must be online * to run a core test. It is only necessary to test one thread. * * For e.g. to test core corresponding to cpu5 * * # echo 5 > /sys/devices/virtual/misc/intel_ifs_<n>/run_test * * Results of the last test is provided in /sys:: * * $ cat /sys/devices/virtual/misc/intel_ifs_<n>/status * pass * * Status can be one of pass, fail, untested * * Additional details of the last test is provided by the details file:: * * $ cat /sys/devices/virtual/misc/intel_ifs_<n>/details * 0x8081 * * The details file reports the hex value of the test specific status MSR. * Hardware defined error codes are documented in volume 4 of the Intel * Software Developer's Manual but the error_code field may contain one of * the following driver defined software codes: * * +------+--------------------+ * | 0xFD | Software timeout | * +------+--------------------+ * | 0xFE | Partial completion | * +------+--------------------+ * * Driver design choices * --------------------- * * 1) The ACTIVATE_SCAN MSR allows for running any consecutive subrange of * available tests. But the driver always tries to run all tests and only * uses the subrange feature to restart an interrupted test. * * 2) Hardware allows for some number of cores to be tested in parallel. * The driver does not make use of this, it only tests one core at a time. * * .. [#f1] https://github.com/intel/TBD */ #include <linux/device.h> #include <linux/miscdevice.h> #define MSR_ARRAY_BIST … #define MSR_COPY_SCAN_HASHES … #define MSR_SCAN_HASHES_STATUS … #define MSR_AUTHENTICATE_AND_COPY_CHUNK … #define MSR_CHUNKS_AUTHENTICATION_STATUS … #define MSR_ACTIVATE_SCAN … #define MSR_SCAN_STATUS … #define MSR_ARRAY_TRIGGER … #define MSR_ARRAY_STATUS … #define MSR_SAF_CTRL … #define SCAN_NOT_TESTED … #define SCAN_TEST_PASS … #define SCAN_TEST_FAIL … #define IFS_TYPE_SAF … #define IFS_TYPE_ARRAY_BIST … #define ARRAY_GEN0 … #define ARRAY_GEN1 … /* MSR_SCAN_HASHES_STATUS bit fields */ ifs_scan_hashes_status; ifs_scan_hashes_status_gen2; /* MSR_CHUNKS_AUTH_STATUS bit fields */ ifs_chunks_auth_status; ifs_chunks_auth_status_gen2; /* MSR_ACTIVATE_SCAN bit fields */ ifs_scan; /* MSR_SCAN_STATUS bit fields */ ifs_status; /* MSR_ARRAY_BIST bit fields */ ifs_array; /* * Driver populated error-codes * 0xFD: Test timed out before completing all the chunks. * 0xFE: not all scan chunks were executed. Maximum forward progress retries exceeded. */ #define IFS_SW_TIMEOUT … #define IFS_SW_PARTIAL_COMPLETION … struct ifs_test_caps { … }; /** * struct ifs_data - attributes related to intel IFS driver * @loaded_version: stores the currently loaded ifs image version. * @loaded: If a valid test binary has been loaded into the memory * @loading_error: Error occurred on another CPU while loading image * @valid_chunks: number of chunks which could be validated. * @status: it holds simple status pass/fail/untested * @scan_details: opaque scan status code from h/w * @cur_batch: number indicating the currently loaded test file * @generation: IFS test generation enumerated by hardware * @chunk_size: size of a test chunk * @array_gen: test generation of array test */ struct ifs_data { … }; struct ifs_work { … }; struct ifs_device { … }; static inline struct ifs_data *ifs_get_data(struct device *dev) { … } static inline const struct ifs_test_caps *ifs_get_test_caps(struct device *dev) { … } extern bool *ifs_pkg_auth; int ifs_load_firmware(struct device *dev); int do_core_test(int cpu, struct device *dev); extern struct attribute *plat_ifs_attrs[]; extern struct attribute *plat_ifs_array_attrs[]; #endif
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