This source file includes following definitions.
- enable_barrier_nospec
- setup_barrier_nospec
- handle_nospectre_v1
- barrier_nospec_set
- barrier_nospec_get
- barrier_nospec_debugfs_init
- security_feature_debugfs_init
- handle_nospectre_v2
- setup_spectre_v2
- cpu_show_meltdown
- cpu_show_l1tf
- cpu_show_spectre_v1
- cpu_show_spectre_v2
- handle_no_stf_barrier
- handle_ssbd
- handle_no_ssbd
- stf_barrier_enable
- setup_stf_barrier
- cpu_show_spec_store_bypass
- stf_barrier_set
- stf_barrier_get
- stf_barrier_debugfs_init
- no_count_cache_flush
- toggle_count_cache_flush
- setup_count_cache_flush
- count_cache_flush_set
- count_cache_flush_get
- count_cache_flush_debugfs_init
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6
7 #include <linux/cpu.h>
8 #include <linux/kernel.h>
9 #include <linux/device.h>
10 #include <linux/seq_buf.h>
11
12 #include <asm/asm-prototypes.h>
13 #include <asm/code-patching.h>
14 #include <asm/debugfs.h>
15 #include <asm/security_features.h>
16 #include <asm/setup.h>
17
18
19 u64 powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
20
21 enum count_cache_flush_type {
22 COUNT_CACHE_FLUSH_NONE = 0x1,
23 COUNT_CACHE_FLUSH_SW = 0x2,
24 COUNT_CACHE_FLUSH_HW = 0x4,
25 };
26 static enum count_cache_flush_type count_cache_flush_type = COUNT_CACHE_FLUSH_NONE;
27 static bool link_stack_flush_enabled;
28
29 bool barrier_nospec_enabled;
30 static bool no_nospec;
31 static bool btb_flush_enabled;
32 #if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_BOOK3S_64)
33 static bool no_spectrev2;
34 #endif
35
36 static void enable_barrier_nospec(bool enable)
37 {
38 barrier_nospec_enabled = enable;
39 do_barrier_nospec_fixups(enable);
40 }
41
42 void setup_barrier_nospec(void)
43 {
44 bool enable;
45
46
47
48
49
50
51
52
53
54
55
56
57
58 enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
59 security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
60
61 if (!no_nospec && !cpu_mitigations_off())
62 enable_barrier_nospec(enable);
63 }
64
65 static int __init handle_nospectre_v1(char *p)
66 {
67 no_nospec = true;
68
69 return 0;
70 }
71 early_param("nospectre_v1", handle_nospectre_v1);
72
73 #ifdef CONFIG_DEBUG_FS
74 static int barrier_nospec_set(void *data, u64 val)
75 {
76 switch (val) {
77 case 0:
78 case 1:
79 break;
80 default:
81 return -EINVAL;
82 }
83
84 if (!!val == !!barrier_nospec_enabled)
85 return 0;
86
87 enable_barrier_nospec(!!val);
88
89 return 0;
90 }
91
92 static int barrier_nospec_get(void *data, u64 *val)
93 {
94 *val = barrier_nospec_enabled ? 1 : 0;
95 return 0;
96 }
97
98 DEFINE_SIMPLE_ATTRIBUTE(fops_barrier_nospec,
99 barrier_nospec_get, barrier_nospec_set, "%llu\n");
100
101 static __init int barrier_nospec_debugfs_init(void)
102 {
103 debugfs_create_file("barrier_nospec", 0600, powerpc_debugfs_root, NULL,
104 &fops_barrier_nospec);
105 return 0;
106 }
107 device_initcall(barrier_nospec_debugfs_init);
108
109 static __init int security_feature_debugfs_init(void)
110 {
111 debugfs_create_x64("security_features", 0400, powerpc_debugfs_root,
112 &powerpc_security_features);
113 return 0;
114 }
115 device_initcall(security_feature_debugfs_init);
116 #endif
117
118 #if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_BOOK3S_64)
119 static int __init handle_nospectre_v2(char *p)
120 {
121 no_spectrev2 = true;
122
123 return 0;
124 }
125 early_param("nospectre_v2", handle_nospectre_v2);
126 #endif
127
128 #ifdef CONFIG_PPC_FSL_BOOK3E
129 void setup_spectre_v2(void)
130 {
131 if (no_spectrev2 || cpu_mitigations_off())
132 do_btb_flush_fixups();
133 else
134 btb_flush_enabled = true;
135 }
136 #endif
137
138 #ifdef CONFIG_PPC_BOOK3S_64
139 ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
140 {
141 bool thread_priv;
142
143 thread_priv = security_ftr_enabled(SEC_FTR_L1D_THREAD_PRIV);
144
145 if (rfi_flush) {
146 struct seq_buf s;
147 seq_buf_init(&s, buf, PAGE_SIZE - 1);
148
149 seq_buf_printf(&s, "Mitigation: RFI Flush");
150 if (thread_priv)
151 seq_buf_printf(&s, ", L1D private per thread");
152
153 seq_buf_printf(&s, "\n");
154
155 return s.len;
156 }
157
158 if (thread_priv)
159 return sprintf(buf, "Vulnerable: L1D private per thread\n");
160
161 if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
162 !security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
163 return sprintf(buf, "Not affected\n");
164
165 return sprintf(buf, "Vulnerable\n");
166 }
167
168 ssize_t cpu_show_l1tf(struct device *dev, struct device_attribute *attr, char *buf)
169 {
170 return cpu_show_meltdown(dev, attr, buf);
171 }
172 #endif
173
174 ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf)
175 {
176 struct seq_buf s;
177
178 seq_buf_init(&s, buf, PAGE_SIZE - 1);
179
180 if (security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR)) {
181 if (barrier_nospec_enabled)
182 seq_buf_printf(&s, "Mitigation: __user pointer sanitization");
183 else
184 seq_buf_printf(&s, "Vulnerable");
185
186 if (security_ftr_enabled(SEC_FTR_SPEC_BAR_ORI31))
187 seq_buf_printf(&s, ", ori31 speculation barrier enabled");
188
189 seq_buf_printf(&s, "\n");
190 } else
191 seq_buf_printf(&s, "Not affected\n");
192
193 return s.len;
194 }
195
196 ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf)
197 {
198 struct seq_buf s;
199 bool bcs, ccd;
200
201 seq_buf_init(&s, buf, PAGE_SIZE - 1);
202
203 bcs = security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED);
204 ccd = security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED);
205
206 if (bcs || ccd) {
207 seq_buf_printf(&s, "Mitigation: ");
208
209 if (bcs)
210 seq_buf_printf(&s, "Indirect branch serialisation (kernel only)");
211
212 if (bcs && ccd)
213 seq_buf_printf(&s, ", ");
214
215 if (ccd)
216 seq_buf_printf(&s, "Indirect branch cache disabled");
217
218 if (link_stack_flush_enabled)
219 seq_buf_printf(&s, ", Software link stack flush");
220
221 } else if (count_cache_flush_type != COUNT_CACHE_FLUSH_NONE) {
222 seq_buf_printf(&s, "Mitigation: Software count cache flush");
223
224 if (count_cache_flush_type == COUNT_CACHE_FLUSH_HW)
225 seq_buf_printf(&s, " (hardware accelerated)");
226
227 if (link_stack_flush_enabled)
228 seq_buf_printf(&s, ", Software link stack flush");
229
230 } else if (btb_flush_enabled) {
231 seq_buf_printf(&s, "Mitigation: Branch predictor state flush");
232 } else {
233 seq_buf_printf(&s, "Vulnerable");
234 }
235
236 seq_buf_printf(&s, "\n");
237
238 return s.len;
239 }
240
241 #ifdef CONFIG_PPC_BOOK3S_64
242
243
244
245
246 static enum stf_barrier_type stf_enabled_flush_types;
247 static bool no_stf_barrier;
248 bool stf_barrier;
249
250 static int __init handle_no_stf_barrier(char *p)
251 {
252 pr_info("stf-barrier: disabled on command line.");
253 no_stf_barrier = true;
254 return 0;
255 }
256
257 early_param("no_stf_barrier", handle_no_stf_barrier);
258
259
260 static int __init handle_ssbd(char *p)
261 {
262 if (!p || strncmp(p, "auto", 5) == 0 || strncmp(p, "on", 2) == 0 ) {
263
264 return 0;
265 } else if (strncmp(p, "off", 3) == 0) {
266 handle_no_stf_barrier(NULL);
267 return 0;
268 } else
269 return 1;
270
271 return 0;
272 }
273 early_param("spec_store_bypass_disable", handle_ssbd);
274
275
276 static int __init handle_no_ssbd(char *p)
277 {
278 handle_no_stf_barrier(NULL);
279 return 0;
280 }
281 early_param("nospec_store_bypass_disable", handle_no_ssbd);
282
283 static void stf_barrier_enable(bool enable)
284 {
285 if (enable)
286 do_stf_barrier_fixups(stf_enabled_flush_types);
287 else
288 do_stf_barrier_fixups(STF_BARRIER_NONE);
289
290 stf_barrier = enable;
291 }
292
293 void setup_stf_barrier(void)
294 {
295 enum stf_barrier_type type;
296 bool enable, hv;
297
298 hv = cpu_has_feature(CPU_FTR_HVMODE);
299
300
301 if (cpu_has_feature(CPU_FTR_ARCH_300))
302 type = STF_BARRIER_EIEIO;
303 else if (cpu_has_feature(CPU_FTR_ARCH_207S))
304 type = STF_BARRIER_SYNC_ORI;
305 else if (cpu_has_feature(CPU_FTR_ARCH_206))
306 type = STF_BARRIER_FALLBACK;
307 else
308 type = STF_BARRIER_NONE;
309
310 enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
311 (security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR) ||
312 (security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) && hv));
313
314 if (type == STF_BARRIER_FALLBACK) {
315 pr_info("stf-barrier: fallback barrier available\n");
316 } else if (type == STF_BARRIER_SYNC_ORI) {
317 pr_info("stf-barrier: hwsync barrier available\n");
318 } else if (type == STF_BARRIER_EIEIO) {
319 pr_info("stf-barrier: eieio barrier available\n");
320 }
321
322 stf_enabled_flush_types = type;
323
324 if (!no_stf_barrier && !cpu_mitigations_off())
325 stf_barrier_enable(enable);
326 }
327
328 ssize_t cpu_show_spec_store_bypass(struct device *dev, struct device_attribute *attr, char *buf)
329 {
330 if (stf_barrier && stf_enabled_flush_types != STF_BARRIER_NONE) {
331 const char *type;
332 switch (stf_enabled_flush_types) {
333 case STF_BARRIER_EIEIO:
334 type = "eieio";
335 break;
336 case STF_BARRIER_SYNC_ORI:
337 type = "hwsync";
338 break;
339 case STF_BARRIER_FALLBACK:
340 type = "fallback";
341 break;
342 default:
343 type = "unknown";
344 }
345 return sprintf(buf, "Mitigation: Kernel entry/exit barrier (%s)\n", type);
346 }
347
348 if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
349 !security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
350 return sprintf(buf, "Not affected\n");
351
352 return sprintf(buf, "Vulnerable\n");
353 }
354
355 #ifdef CONFIG_DEBUG_FS
356 static int stf_barrier_set(void *data, u64 val)
357 {
358 bool enable;
359
360 if (val == 1)
361 enable = true;
362 else if (val == 0)
363 enable = false;
364 else
365 return -EINVAL;
366
367
368 if (enable != stf_barrier)
369 stf_barrier_enable(enable);
370
371 return 0;
372 }
373
374 static int stf_barrier_get(void *data, u64 *val)
375 {
376 *val = stf_barrier ? 1 : 0;
377 return 0;
378 }
379
380 DEFINE_SIMPLE_ATTRIBUTE(fops_stf_barrier, stf_barrier_get, stf_barrier_set, "%llu\n");
381
382 static __init int stf_barrier_debugfs_init(void)
383 {
384 debugfs_create_file("stf_barrier", 0600, powerpc_debugfs_root, NULL, &fops_stf_barrier);
385 return 0;
386 }
387 device_initcall(stf_barrier_debugfs_init);
388 #endif
389
390 static void no_count_cache_flush(void)
391 {
392 count_cache_flush_type = COUNT_CACHE_FLUSH_NONE;
393 pr_info("count-cache-flush: software flush disabled.\n");
394 }
395
396 static void toggle_count_cache_flush(bool enable)
397 {
398 if (!security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE) &&
399 !security_ftr_enabled(SEC_FTR_FLUSH_LINK_STACK))
400 enable = false;
401
402 if (!enable) {
403 patch_instruction_site(&patch__call_flush_count_cache, PPC_INST_NOP);
404 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
405 patch_instruction_site(&patch__call_kvm_flush_link_stack, PPC_INST_NOP);
406 #endif
407 pr_info("link-stack-flush: software flush disabled.\n");
408 link_stack_flush_enabled = false;
409 no_count_cache_flush();
410 return;
411 }
412
413
414 patch_branch_site(&patch__call_flush_count_cache,
415 (u64)&flush_count_cache, BRANCH_SET_LINK);
416
417 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
418
419 patch_branch_site(&patch__call_kvm_flush_link_stack,
420 (u64)&kvm_flush_link_stack, BRANCH_SET_LINK);
421 #endif
422
423 pr_info("link-stack-flush: software flush enabled.\n");
424 link_stack_flush_enabled = true;
425
426
427 if (!security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE)) {
428 patch_instruction_site(&patch__flush_link_stack_return, PPC_INST_BLR);
429 no_count_cache_flush();
430 return;
431 }
432
433 if (!security_ftr_enabled(SEC_FTR_BCCTR_FLUSH_ASSIST)) {
434 count_cache_flush_type = COUNT_CACHE_FLUSH_SW;
435 pr_info("count-cache-flush: full software flush sequence enabled.\n");
436 return;
437 }
438
439 patch_instruction_site(&patch__flush_count_cache_return, PPC_INST_BLR);
440 count_cache_flush_type = COUNT_CACHE_FLUSH_HW;
441 pr_info("count-cache-flush: hardware assisted flush sequence enabled\n");
442 }
443
444 void setup_count_cache_flush(void)
445 {
446 bool enable = true;
447
448 if (no_spectrev2 || cpu_mitigations_off()) {
449 if (security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED) ||
450 security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED))
451 pr_warn("Spectre v2 mitigations not fully under software control, can't disable\n");
452
453 enable = false;
454 }
455
456
457
458
459
460
461 if (security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED) ||
462 security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE))
463 security_ftr_set(SEC_FTR_FLUSH_LINK_STACK);
464
465 toggle_count_cache_flush(enable);
466 }
467
468 #ifdef CONFIG_DEBUG_FS
469 static int count_cache_flush_set(void *data, u64 val)
470 {
471 bool enable;
472
473 if (val == 1)
474 enable = true;
475 else if (val == 0)
476 enable = false;
477 else
478 return -EINVAL;
479
480 toggle_count_cache_flush(enable);
481
482 return 0;
483 }
484
485 static int count_cache_flush_get(void *data, u64 *val)
486 {
487 if (count_cache_flush_type == COUNT_CACHE_FLUSH_NONE)
488 *val = 0;
489 else
490 *val = 1;
491
492 return 0;
493 }
494
495 DEFINE_SIMPLE_ATTRIBUTE(fops_count_cache_flush, count_cache_flush_get,
496 count_cache_flush_set, "%llu\n");
497
498 static __init int count_cache_flush_debugfs_init(void)
499 {
500 debugfs_create_file("count_cache_flush", 0600, powerpc_debugfs_root,
501 NULL, &fops_count_cache_flush);
502 return 0;
503 }
504 device_initcall(count_cache_flush_debugfs_init);
505 #endif
506 #endif