1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* Copyright(c) 2022 Intel Corporation. */ 3 4 #ifndef _IFS_H_ 5 #define _IFS_H_ 6 7 /** 8 * DOC: In-Field Scan 9 * 10 * ============= 11 * In-Field Scan 12 * ============= 13 * 14 * Introduction 15 * ------------ 16 * 17 * In Field Scan (IFS) is a hardware feature to run circuit level tests on 18 * a CPU core to detect problems that are not caught by parity or ECC checks. 19 * Future CPUs will support more than one type of test which will show up 20 * with a new platform-device instance-id, for now only .0 is exposed. 21 * 22 * 23 * IFS Image 24 * --------- 25 * 26 * Intel provides a firmware file containing the scan tests via 27 * github [#f1]_. Similar to microcode there is a separate file for each 28 * family-model-stepping. 29 * 30 * IFS Image Loading 31 * ----------------- 32 * 33 * The driver loads the tests into memory reserved BIOS local to each CPU 34 * socket in a two step process using writes to MSRs to first load the 35 * SHA hashes for the test. Then the tests themselves. Status MSRs provide 36 * feedback on the success/failure of these steps. When a new test file 37 * is installed it can be loaded by writing to the driver reload file:: 38 * 39 * # echo 1 > /sys/devices/virtual/misc/intel_ifs_0/reload 40 * 41 * Similar to microcode, the current version of the scan tests is stored 42 * in a fixed location: /lib/firmware/intel/ifs.0/family-model-stepping.scan 43 * 44 * Running tests 45 * ------------- 46 * 47 * Tests are run by the driver synchronizing execution of all threads on a 48 * core and then writing to the ACTIVATE_SCAN MSR on all threads. Instruction 49 * execution continues when: 50 * 51 * 1) All tests have completed. 52 * 2) Execution was interrupted. 53 * 3) A test detected a problem. 54 * 55 * Note that ALL THREADS ON THE CORE ARE EFFECTIVELY OFFLINE FOR THE 56 * DURATION OF THE TEST. This can be up to 200 milliseconds. If the system 57 * is running latency sensitive applications that cannot tolerate an 58 * interruption of this magnitude, the system administrator must arrange 59 * to migrate those applications to other cores before running a core test. 60 * It may also be necessary to redirect interrupts to other CPUs. 61 * 62 * In all cases reading the SCAN_STATUS MSR provides details on what 63 * happened. The driver makes the value of this MSR visible to applications 64 * via the "details" file (see below). Interrupted tests may be restarted. 65 * 66 * The IFS driver provides sysfs interfaces via /sys/devices/virtual/misc/intel_ifs_0/ 67 * to control execution: 68 * 69 * Test a specific core:: 70 * 71 * # echo <cpu#> > /sys/devices/virtual/misc/intel_ifs_0/run_test 72 * 73 * when HT is enabled any of the sibling cpu# can be specified to test 74 * its corresponding physical core. Since the tests are per physical core, 75 * the result of testing any thread is same. All siblings must be online 76 * to run a core test. It is only necessary to test one thread. 77 * 78 * For e.g. to test core corresponding to cpu5 79 * 80 * # echo 5 > /sys/devices/virtual/misc/intel_ifs_0/run_test 81 * 82 * Results of the last test is provided in /sys:: 83 * 84 * $ cat /sys/devices/virtual/misc/intel_ifs_0/status 85 * pass 86 * 87 * Status can be one of pass, fail, untested 88 * 89 * Additional details of the last test is provided by the details file:: 90 * 91 * $ cat /sys/devices/virtual/misc/intel_ifs_0/details 92 * 0x8081 93 * 94 * The details file reports the hex value of the SCAN_STATUS MSR. 95 * Hardware defined error codes are documented in volume 4 of the Intel 96 * Software Developer's Manual but the error_code field may contain one of 97 * the following driver defined software codes: 98 * 99 * +------+--------------------+ 100 * | 0xFD | Software timeout | 101 * +------+--------------------+ 102 * | 0xFE | Partial completion | 103 * +------+--------------------+ 104 * 105 * Driver design choices 106 * --------------------- 107 * 108 * 1) The ACTIVATE_SCAN MSR allows for running any consecutive subrange of 109 * available tests. But the driver always tries to run all tests and only 110 * uses the subrange feature to restart an interrupted test. 111 * 112 * 2) Hardware allows for some number of cores to be tested in parallel. 113 * The driver does not make use of this, it only tests one core at a time. 114 * 115 * .. [#f1] https://github.com/intel/TBD 116 */ 117 #include <linux/device.h> 118 #include <linux/miscdevice.h> 119 120 #define MSR_COPY_SCAN_HASHES 0x000002c2 121 #define MSR_SCAN_HASHES_STATUS 0x000002c3 122 #define MSR_AUTHENTICATE_AND_COPY_CHUNK 0x000002c4 123 #define MSR_CHUNKS_AUTHENTICATION_STATUS 0x000002c5 124 #define MSR_ACTIVATE_SCAN 0x000002c6 125 #define MSR_SCAN_STATUS 0x000002c7 126 #define SCAN_NOT_TESTED 0 127 #define SCAN_TEST_PASS 1 128 #define SCAN_TEST_FAIL 2 129 130 /* MSR_SCAN_HASHES_STATUS bit fields */ 131 union ifs_scan_hashes_status { 132 u64 data; 133 struct { 134 u32 chunk_size :16; 135 u32 num_chunks :8; 136 u32 rsvd1 :8; 137 u32 error_code :8; 138 u32 rsvd2 :11; 139 u32 max_core_limit :12; 140 u32 valid :1; 141 }; 142 }; 143 144 /* MSR_CHUNKS_AUTH_STATUS bit fields */ 145 union ifs_chunks_auth_status { 146 u64 data; 147 struct { 148 u32 valid_chunks :8; 149 u32 total_chunks :8; 150 u32 rsvd1 :16; 151 u32 error_code :8; 152 u32 rsvd2 :24; 153 }; 154 }; 155 156 /* MSR_ACTIVATE_SCAN bit fields */ 157 union ifs_scan { 158 u64 data; 159 struct { 160 u32 start :8; 161 u32 stop :8; 162 u32 rsvd :16; 163 u32 delay :31; 164 u32 sigmce :1; 165 }; 166 }; 167 168 /* MSR_SCAN_STATUS bit fields */ 169 union ifs_status { 170 u64 data; 171 struct { 172 u32 chunk_num :8; 173 u32 chunk_stop_index :8; 174 u32 rsvd1 :16; 175 u32 error_code :8; 176 u32 rsvd2 :22; 177 u32 control_error :1; 178 u32 signature_error :1; 179 }; 180 }; 181 182 /* 183 * Driver populated error-codes 184 * 0xFD: Test timed out before completing all the chunks. 185 * 0xFE: not all scan chunks were executed. Maximum forward progress retries exceeded. 186 */ 187 #define IFS_SW_TIMEOUT 0xFD 188 #define IFS_SW_PARTIAL_COMPLETION 0xFE 189 190 /** 191 * struct ifs_data - attributes related to intel IFS driver 192 * @integrity_cap_bit: MSR_INTEGRITY_CAPS bit enumerating this test 193 * @loaded_version: stores the currently loaded ifs image version. 194 * @loaded: If a valid test binary has been loaded into the memory 195 * @loading_error: Error occurred on another CPU while loading image 196 * @valid_chunks: number of chunks which could be validated. 197 * @status: it holds simple status pass/fail/untested 198 * @scan_details: opaque scan status code from h/w 199 */ 200 struct ifs_data { 201 int integrity_cap_bit; 202 int loaded_version; 203 bool loaded; 204 bool loading_error; 205 int valid_chunks; 206 int status; 207 u64 scan_details; 208 }; 209 210 struct ifs_work { 211 struct work_struct w; 212 struct device *dev; 213 }; 214 215 struct ifs_device { 216 struct ifs_data data; 217 struct miscdevice misc; 218 }; 219 220 static inline struct ifs_data *ifs_get_data(struct device *dev) 221 { 222 struct miscdevice *m = dev_get_drvdata(dev); 223 struct ifs_device *d = container_of(m, struct ifs_device, misc); 224 225 return &d->data; 226 } 227 228 void ifs_load_firmware(struct device *dev); 229 int do_core_test(int cpu, struct device *dev); 230 const struct attribute_group **ifs_get_groups(void); 231 232 extern struct semaphore ifs_sem; 233 234 #endif 235