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.
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. IFS Images are not applicable for some test types.
29 * Wherever applicable the sysfs directory would provide a "current_batch" file
30 * (see below) for loading the image.
31 *
32 *
33 * IFS Image Loading
34 * -----------------
35 *
36 * The driver loads the tests into memory reserved BIOS local to each CPU
37 * socket in a two step process using writes to MSRs to first load the
38 * SHA hashes for the test. Then the tests themselves. Status MSRs provide
39 * feedback on the success/failure of these steps.
40 *
41 * The test files are kept in a fixed location: /lib/firmware/intel/ifs_<n>/
42 * For e.g if there are 3 test files, they would be named in the following
43 * fashion:
44 * ff-mm-ss-01.scan
45 * ff-mm-ss-02.scan
46 * ff-mm-ss-03.scan
47 * (where ff refers to family, mm indicates model and ss indicates stepping)
48 *
49 * A different test file can be loaded by writing the numerical portion
50 * (e.g 1, 2 or 3 in the above scenario) into the curent_batch file.
51 * To load ff-mm-ss-02.scan, the following command can be used::
52 *
53 * # echo 2 > /sys/devices/virtual/misc/intel_ifs_<n>/current_batch
54 *
55 * The above file can also be read to know the currently loaded image.
56 *
57 * Running tests
58 * -------------
59 *
60 * Tests are run by the driver synchronizing execution of all threads on a
61 * core and then writing to the ACTIVATE_SCAN MSR on all threads. Instruction
62 * execution continues when:
63 *
64 * 1) All tests have completed.
65 * 2) Execution was interrupted.
66 * 3) A test detected a problem.
67 *
68 * Note that ALL THREADS ON THE CORE ARE EFFECTIVELY OFFLINE FOR THE
69 * DURATION OF THE TEST. This can be up to 200 milliseconds. If the system
70 * is running latency sensitive applications that cannot tolerate an
71 * interruption of this magnitude, the system administrator must arrange
72 * to migrate those applications to other cores before running a core test.
73 * It may also be necessary to redirect interrupts to other CPUs.
74 *
75 * In all cases reading the corresponding test's STATUS MSR provides details on what
76 * happened. The driver makes the value of this MSR visible to applications
77 * via the "details" file (see below). Interrupted tests may be restarted.
78 *
79 * The IFS driver provides sysfs interfaces via /sys/devices/virtual/misc/intel_ifs_<n>/
80 * to control execution:
81 *
82 * Test a specific core::
83 *
84 * # echo <cpu#> > /sys/devices/virtual/misc/intel_ifs_<n>/run_test
85 *
86 * when HT is enabled any of the sibling cpu# can be specified to test
87 * its corresponding physical core. Since the tests are per physical core,
88 * the result of testing any thread is same. All siblings must be online
89 * to run a core test. It is only necessary to test one thread.
90 *
91 * For e.g. to test core corresponding to cpu5
92 *
93 * # echo 5 > /sys/devices/virtual/misc/intel_ifs_<n>/run_test
94 *
95 * Results of the last test is provided in /sys::
96 *
97 * $ cat /sys/devices/virtual/misc/intel_ifs_<n>/status
98 * pass
99 *
100 * Status can be one of pass, fail, untested
101 *
102 * Additional details of the last test is provided by the details file::
103 *
104 * $ cat /sys/devices/virtual/misc/intel_ifs_<n>/details
105 * 0x8081
106 *
107 * The details file reports the hex value of the test specific status MSR.
108 * Hardware defined error codes are documented in volume 4 of the Intel
109 * Software Developer's Manual but the error_code field may contain one of
110 * the following driver defined software codes:
111 *
112 * +------+--------------------+
113 * | 0xFD | Software timeout |
114 * +------+--------------------+
115 * | 0xFE | Partial completion |
116 * +------+--------------------+
117 *
118 * Driver design choices
119 * ---------------------
120 *
121 * 1) The ACTIVATE_SCAN MSR allows for running any consecutive subrange of
122 * available tests. But the driver always tries to run all tests and only
123 * uses the subrange feature to restart an interrupted test.
124 *
125 * 2) Hardware allows for some number of cores to be tested in parallel.
126 * The driver does not make use of this, it only tests one core at a time.
127 *
128 * .. [#f1] https://github.com/intel/TBD
129 */
130 #include <linux/device.h>
131 #include <linux/miscdevice.h>
132
133 #define MSR_ARRAY_BIST 0x00000105
134 #define MSR_COPY_SCAN_HASHES 0x000002c2
135 #define MSR_SCAN_HASHES_STATUS 0x000002c3
136 #define MSR_AUTHENTICATE_AND_COPY_CHUNK 0x000002c4
137 #define MSR_CHUNKS_AUTHENTICATION_STATUS 0x000002c5
138 #define MSR_ACTIVATE_SCAN 0x000002c6
139 #define MSR_SCAN_STATUS 0x000002c7
140 #define SCAN_NOT_TESTED 0
141 #define SCAN_TEST_PASS 1
142 #define SCAN_TEST_FAIL 2
143
144 #define IFS_TYPE_SAF 0
145 #define IFS_TYPE_ARRAY_BIST 1
146
147 /* MSR_SCAN_HASHES_STATUS bit fields */
148 union ifs_scan_hashes_status {
149 u64 data;
150 struct {
151 u32 chunk_size :16;
152 u32 num_chunks :8;
153 u32 rsvd1 :8;
154 u32 error_code :8;
155 u32 rsvd2 :11;
156 u32 max_core_limit :12;
157 u32 valid :1;
158 };
159 };
160
161 /* MSR_CHUNKS_AUTH_STATUS bit fields */
162 union ifs_chunks_auth_status {
163 u64 data;
164 struct {
165 u32 valid_chunks :8;
166 u32 total_chunks :8;
167 u32 rsvd1 :16;
168 u32 error_code :8;
169 u32 rsvd2 :24;
170 };
171 };
172
173 /* MSR_ACTIVATE_SCAN bit fields */
174 union ifs_scan {
175 u64 data;
176 struct {
177 u32 start :8;
178 u32 stop :8;
179 u32 rsvd :16;
180 u32 delay :31;
181 u32 sigmce :1;
182 };
183 };
184
185 /* MSR_SCAN_STATUS bit fields */
186 union ifs_status {
187 u64 data;
188 struct {
189 u32 chunk_num :8;
190 u32 chunk_stop_index :8;
191 u32 rsvd1 :16;
192 u32 error_code :8;
193 u32 rsvd2 :22;
194 u32 control_error :1;
195 u32 signature_error :1;
196 };
197 };
198
199 /* MSR_ARRAY_BIST bit fields */
200 union ifs_array {
201 u64 data;
202 struct {
203 u32 array_bitmask;
204 u16 array_bank;
205 u16 rsvd :15;
206 u16 ctrl_result :1;
207 };
208 };
209
210 /*
211 * Driver populated error-codes
212 * 0xFD: Test timed out before completing all the chunks.
213 * 0xFE: not all scan chunks were executed. Maximum forward progress retries exceeded.
214 */
215 #define IFS_SW_TIMEOUT 0xFD
216 #define IFS_SW_PARTIAL_COMPLETION 0xFE
217
218 struct ifs_test_caps {
219 int integrity_cap_bit;
220 int test_num;
221 };
222
223 /**
224 * struct ifs_data - attributes related to intel IFS driver
225 * @loaded_version: stores the currently loaded ifs image version.
226 * @loaded: If a valid test binary has been loaded into the memory
227 * @loading_error: Error occurred on another CPU while loading image
228 * @valid_chunks: number of chunks which could be validated.
229 * @status: it holds simple status pass/fail/untested
230 * @scan_details: opaque scan status code from h/w
231 * @cur_batch: number indicating the currently loaded test file
232 */
233 struct ifs_data {
234 int loaded_version;
235 bool loaded;
236 bool loading_error;
237 int valid_chunks;
238 int status;
239 u64 scan_details;
240 u32 cur_batch;
241 };
242
243 struct ifs_work {
244 struct work_struct w;
245 struct device *dev;
246 };
247
248 struct ifs_device {
249 const struct ifs_test_caps *test_caps;
250 struct ifs_data rw_data;
251 struct miscdevice misc;
252 };
253
ifs_get_data(struct device * dev)254 static inline struct ifs_data *ifs_get_data(struct device *dev)
255 {
256 struct miscdevice *m = dev_get_drvdata(dev);
257 struct ifs_device *d = container_of(m, struct ifs_device, misc);
258
259 return &d->rw_data;
260 }
261
ifs_get_test_caps(struct device * dev)262 static inline const struct ifs_test_caps *ifs_get_test_caps(struct device *dev)
263 {
264 struct miscdevice *m = dev_get_drvdata(dev);
265 struct ifs_device *d = container_of(m, struct ifs_device, misc);
266
267 return d->test_caps;
268 }
269
270 extern bool *ifs_pkg_auth;
271 int ifs_load_firmware(struct device *dev);
272 int do_core_test(int cpu, struct device *dev);
273 extern struct attribute *plat_ifs_attrs[];
274 extern struct attribute *plat_ifs_array_attrs[];
275
276 #endif
277