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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1353ebb4 | 2 | /* |
1353ebb4 JF |
3 | * Copyright (C) 1994 Linus Torvalds |
4 | * | |
5 | * Cyrix stuff, June 1998 by: | |
6 | * - Rafael R. Reilova (moved everything from head.S), | |
7 | * <rreilova@ececs.uc.edu> | |
8 | * - Channing Corn (tests & fixes), | |
9 | * - Andrew D. Balsa (code cleanup). | |
10 | */ | |
11 | #include <linux/init.h> | |
12 | #include <linux/utsname.h> | |
61dc0f55 | 13 | #include <linux/cpu.h> |
caf7501a | 14 | #include <linux/module.h> |
a73ec77e TG |
15 | #include <linux/nospec.h> |
16 | #include <linux/prctl.h> | |
a74cfffb | 17 | #include <linux/sched/smt.h> |
65fddcfc | 18 | #include <linux/pgtable.h> |
534fcc9a | 19 | #include <linux/bpf.h> |
da285121 | 20 | |
28a27752 | 21 | #include <asm/spec-ctrl.h> |
da285121 | 22 | #include <asm/cmdline.h> |
91eb1b79 | 23 | #include <asm/bugs.h> |
1353ebb4 | 24 | #include <asm/processor.h> |
7ebad705 | 25 | #include <asm/processor-flags.h> |
4e85b53e | 26 | #include <asm/fpu/api.h> |
1353ebb4 | 27 | #include <asm/msr.h> |
72c6d2db | 28 | #include <asm/vmx.h> |
1353ebb4 JF |
29 | #include <asm/paravirt.h> |
30 | #include <asm/alternative.h> | |
d1163651 | 31 | #include <asm/set_memory.h> |
c995efd5 | 32 | #include <asm/intel-family.h> |
17dbca11 | 33 | #include <asm/e820/api.h> |
6cb2b08f | 34 | #include <asm/hypervisor.h> |
f29dfa53 | 35 | #include <asm/tlbflush.h> |
1353ebb4 | 36 | |
ad3bc25a BP |
37 | #include "cpu.h" |
38 | ||
a2059825 | 39 | static void __init spectre_v1_select_mitigation(void); |
da285121 | 40 | static void __init spectre_v2_select_mitigation(void); |
b4e79f4b PZ |
41 | static void __init retbleed_select_mitigation(void); |
42 | static void __init spectre_v2_user_select_mitigation(void); | |
24f7fc83 | 43 | static void __init ssb_select_mitigation(void); |
17dbca11 | 44 | static void __init l1tf_select_mitigation(void); |
bc124170 | 45 | static void __init mds_select_mitigation(void); |
6a9231bf | 46 | static void __init md_clear_update_mitigation(void); |
b9bc1fb8 | 47 | static void __init md_clear_select_mitigation(void); |
1b42f017 | 48 | static void __init taa_select_mitigation(void); |
2418c6b1 | 49 | static void __init mmio_select_mitigation(void); |
7e5b3c26 | 50 | static void __init srbds_select_mitigation(void); |
b5f06f64 | 51 | static void __init l1d_flush_select_mitigation(void); |
da285121 | 52 | |
113521bb | 53 | /* The base value of the SPEC_CTRL MSR without task-specific bits set */ |
53c613fe | 54 | u64 x86_spec_ctrl_base; |
fa8ac498 | 55 | EXPORT_SYMBOL_GPL(x86_spec_ctrl_base); |
113521bb PZ |
56 | |
57 | /* The current value of the SPEC_CTRL MSR with task-specific bits set */ | |
58 | DEFINE_PER_CPU(u64, x86_spec_ctrl_current); | |
59 | EXPORT_SYMBOL_GPL(x86_spec_ctrl_current); | |
60 | ||
53c613fe | 61 | static DEFINE_MUTEX(spec_ctrl_mutex); |
1b86883c | 62 | |
113521bb PZ |
63 | /* |
64 | * Keep track of the SPEC_CTRL MSR value for the current task, which may differ | |
65 | * from x86_spec_ctrl_base due to STIBP/SSB in __speculation_ctrl_update(). | |
66 | */ | |
1d800213 | 67 | void write_spec_ctrl_current(u64 val, bool force) |
113521bb PZ |
68 | { |
69 | if (this_cpu_read(x86_spec_ctrl_current) == val) | |
70 | return; | |
71 | ||
72 | this_cpu_write(x86_spec_ctrl_current, val); | |
1d800213 PZ |
73 | |
74 | /* | |
75 | * When KERNEL_IBRS this MSR is written on return-to-user, unless | |
76 | * forced the update can be delayed until that time. | |
77 | */ | |
78 | if (force || !cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS)) | |
79 | wrmsrl(MSR_IA32_SPEC_CTRL, val); | |
113521bb PZ |
80 | } |
81 | ||
44ba0d1d PZ |
82 | u64 spec_ctrl_current(void) |
83 | { | |
84 | return this_cpu_read(x86_spec_ctrl_current); | |
85 | } | |
86 | EXPORT_SYMBOL_GPL(spec_ctrl_current); | |
87 | ||
764f3c21 KRW |
88 | /* |
89 | * AMD specific MSR info for Speculative Store Bypass control. | |
9f65fb29 | 90 | * x86_amd_ls_cfg_ssbd_mask is initialized in identify_boot_cpu(). |
764f3c21 KRW |
91 | */ |
92 | u64 __ro_after_init x86_amd_ls_cfg_base; | |
9f65fb29 | 93 | u64 __ro_after_init x86_amd_ls_cfg_ssbd_mask; |
764f3c21 | 94 | |
aa77bfb3 | 95 | /* Control conditional STIBP in switch_to() */ |
fa1202ef | 96 | DEFINE_STATIC_KEY_FALSE(switch_to_cond_stibp); |
4c71a2b6 TG |
97 | /* Control conditional IBPB in switch_mm() */ |
98 | DEFINE_STATIC_KEY_FALSE(switch_mm_cond_ibpb); | |
99 | /* Control unconditional IBPB in switch_mm() */ | |
100 | DEFINE_STATIC_KEY_FALSE(switch_mm_always_ibpb); | |
fa1202ef | 101 | |
04dcbdb8 TG |
102 | /* Control MDS CPU buffer clear before returning to user space */ |
103 | DEFINE_STATIC_KEY_FALSE(mds_user_clear); | |
650b68a0 | 104 | EXPORT_SYMBOL_GPL(mds_user_clear); |
07f07f55 TG |
105 | /* Control MDS CPU buffer clear before idling (halt, mwait) */ |
106 | DEFINE_STATIC_KEY_FALSE(mds_idle_clear); | |
107 | EXPORT_SYMBOL_GPL(mds_idle_clear); | |
04dcbdb8 | 108 | |
b5f06f64 BS |
109 | /* |
110 | * Controls whether l1d flush based mitigations are enabled, | |
111 | * based on hw features and admin setting via boot parameter | |
112 | * defaults to false | |
113 | */ | |
114 | DEFINE_STATIC_KEY_FALSE(switch_mm_cond_l1d_flush); | |
115 | ||
2418c6b1 PG |
116 | /* Controls CPU Fill buffer clear before KVM guest MMIO accesses */ |
117 | DEFINE_STATIC_KEY_FALSE(mmio_stale_data_clear); | |
118 | EXPORT_SYMBOL_GPL(mmio_stale_data_clear); | |
119 | ||
1353ebb4 JF |
120 | void __init check_bugs(void) |
121 | { | |
122 | identify_boot_cpu(); | |
55a36b65 | 123 | |
fee0aede TG |
124 | /* |
125 | * identify_boot_cpu() initialized SMT support information, let the | |
126 | * core code know. | |
127 | */ | |
b284909a | 128 | cpu_smt_check_topology(); |
fee0aede | 129 | |
62a67e12 BP |
130 | if (!IS_ENABLED(CONFIG_SMP)) { |
131 | pr_info("CPU: "); | |
132 | print_cpu_info(&boot_cpu_data); | |
133 | } | |
134 | ||
1b86883c KRW |
135 | /* |
136 | * Read the SPEC_CTRL MSR to account for reserved bits which may | |
764f3c21 KRW |
137 | * have unknown values. AMD64_LS_CFG MSR is cached in the early AMD |
138 | * init code as it is not enumerated and depends on the family. | |
1b86883c | 139 | */ |
7eb8956a | 140 | if (boot_cpu_has(X86_FEATURE_MSR_SPEC_CTRL)) |
1b86883c KRW |
141 | rdmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); |
142 | ||
a2059825 JP |
143 | /* Select the proper CPU mitigations before patching alternatives: */ |
144 | spectre_v1_select_mitigation(); | |
b4e79f4b PZ |
145 | spectre_v2_select_mitigation(); |
146 | /* | |
147 | * retbleed_select_mitigation() relies on the state set by | |
148 | * spectre_v2_select_mitigation(); specifically it wants to know about | |
149 | * spectre_v2=ibrs. | |
150 | */ | |
8ed18e15 AC |
151 | retbleed_select_mitigation(); |
152 | /* | |
b4e79f4b | 153 | * spectre_v2_user_select_mitigation() relies on the state set by |
8ed18e15 AC |
154 | * retbleed_select_mitigation(); specifically the STIBP selection is |
155 | * forced for UNRET. | |
156 | */ | |
b4e79f4b | 157 | spectre_v2_user_select_mitigation(); |
24f7fc83 | 158 | ssb_select_mitigation(); |
17dbca11 | 159 | l1tf_select_mitigation(); |
b9bc1fb8 | 160 | md_clear_select_mitigation(); |
7e5b3c26 | 161 | srbds_select_mitigation(); |
b5f06f64 | 162 | l1d_flush_select_mitigation(); |
bc124170 | 163 | |
7c3658b2 JP |
164 | arch_smt_update(); |
165 | ||
62a67e12 | 166 | #ifdef CONFIG_X86_32 |
55a36b65 BP |
167 | /* |
168 | * Check whether we are able to run this kernel safely on SMP. | |
169 | * | |
170 | * - i386 is no longer supported. | |
171 | * - In order to run on anything without a TSC, we need to be | |
172 | * compiled for a i486. | |
173 | */ | |
174 | if (boot_cpu_data.x86 < 4) | |
175 | panic("Kernel requires i486+ for 'invlpg' and other features"); | |
176 | ||
bfe4bb15 MV |
177 | init_utsname()->machine[1] = |
178 | '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86); | |
1353ebb4 | 179 | alternative_instructions(); |
304bceda | 180 | |
4d164092 | 181 | fpu__init_check_bugs(); |
62a67e12 BP |
182 | #else /* CONFIG_X86_64 */ |
183 | alternative_instructions(); | |
184 | ||
185 | /* | |
186 | * Make sure the first 2MB area is not mapped by huge pages | |
187 | * There are typically fixed size MTRRs in there and overlapping | |
188 | * MTRRs into large pages causes slow downs. | |
189 | * | |
190 | * Right now we don't do that with gbpages because there seems | |
191 | * very little benefit for that case. | |
192 | */ | |
193 | if (!direct_gbpages) | |
194 | set_memory_4k((unsigned long)__va(0), 1); | |
195 | #endif | |
1353ebb4 | 196 | } |
61dc0f55 | 197 | |
68d98cfd | 198 | /* |
85561a53 JP |
199 | * NOTE: This function is *only* called for SVM. VMX spec_ctrl handling is |
200 | * done in vmenter.S. | |
68d98cfd | 201 | */ |
cc69b349 BP |
202 | void |
203 | x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest) | |
5cf68754 | 204 | { |
a928727e | 205 | u64 msrval, guestval = guest_spec_ctrl, hostval = spec_ctrl_current(); |
cc69b349 | 206 | struct thread_info *ti = current_thread_info(); |
885f82bf | 207 | |
cc69b349 | 208 | if (static_cpu_has(X86_FEATURE_MSR_SPEC_CTRL)) { |
be6fcb54 TG |
209 | if (hostval != guestval) { |
210 | msrval = setguest ? guestval : hostval; | |
211 | wrmsrl(MSR_IA32_SPEC_CTRL, msrval); | |
cc69b349 BP |
212 | } |
213 | } | |
47c61b39 TG |
214 | |
215 | /* | |
216 | * If SSBD is not handled in MSR_SPEC_CTRL on AMD, update | |
217 | * MSR_AMD64_L2_CFG or MSR_VIRT_SPEC_CTRL if supported. | |
218 | */ | |
219 | if (!static_cpu_has(X86_FEATURE_LS_CFG_SSBD) && | |
220 | !static_cpu_has(X86_FEATURE_VIRT_SSBD)) | |
221 | return; | |
222 | ||
223 | /* | |
224 | * If the host has SSBD mitigation enabled, force it in the host's | |
225 | * virtual MSR value. If its not permanently enabled, evaluate | |
226 | * current's TIF_SSBD thread flag. | |
227 | */ | |
228 | if (static_cpu_has(X86_FEATURE_SPEC_STORE_BYPASS_DISABLE)) | |
229 | hostval = SPEC_CTRL_SSBD; | |
230 | else | |
231 | hostval = ssbd_tif_to_spec_ctrl(ti->flags); | |
232 | ||
233 | /* Sanitize the guest value */ | |
234 | guestval = guest_virt_spec_ctrl & SPEC_CTRL_SSBD; | |
235 | ||
236 | if (hostval != guestval) { | |
237 | unsigned long tif; | |
238 | ||
239 | tif = setguest ? ssbd_spec_ctrl_to_tif(guestval) : | |
240 | ssbd_spec_ctrl_to_tif(hostval); | |
241 | ||
26c4d75b | 242 | speculation_ctrl_update(tif); |
47c61b39 | 243 | } |
5cf68754 | 244 | } |
cc69b349 | 245 | EXPORT_SYMBOL_GPL(x86_virt_spec_ctrl); |
5cf68754 | 246 | |
9f65fb29 | 247 | static void x86_amd_ssb_disable(void) |
764f3c21 | 248 | { |
9f65fb29 | 249 | u64 msrval = x86_amd_ls_cfg_base | x86_amd_ls_cfg_ssbd_mask; |
764f3c21 | 250 | |
11fb0683 TL |
251 | if (boot_cpu_has(X86_FEATURE_VIRT_SSBD)) |
252 | wrmsrl(MSR_AMD64_VIRT_SPEC_CTRL, SPEC_CTRL_SSBD); | |
253 | else if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD)) | |
764f3c21 KRW |
254 | wrmsrl(MSR_AMD64_LS_CFG, msrval); |
255 | } | |
256 | ||
bc124170 TG |
257 | #undef pr_fmt |
258 | #define pr_fmt(fmt) "MDS: " fmt | |
259 | ||
cae5ec34 | 260 | /* Default mitigation for MDS-affected CPUs */ |
bc124170 | 261 | static enum mds_mitigations mds_mitigation __ro_after_init = MDS_MITIGATION_FULL; |
d71eb0ce | 262 | static bool mds_nosmt __ro_after_init = false; |
bc124170 TG |
263 | |
264 | static const char * const mds_strings[] = { | |
265 | [MDS_MITIGATION_OFF] = "Vulnerable", | |
22dd8365 TG |
266 | [MDS_MITIGATION_FULL] = "Mitigation: Clear CPU buffers", |
267 | [MDS_MITIGATION_VMWERV] = "Vulnerable: Clear CPU buffers attempted, no microcode", | |
bc124170 TG |
268 | }; |
269 | ||
270 | static void __init mds_select_mitigation(void) | |
271 | { | |
5c14068f | 272 | if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off()) { |
bc124170 TG |
273 | mds_mitigation = MDS_MITIGATION_OFF; |
274 | return; | |
275 | } | |
276 | ||
277 | if (mds_mitigation == MDS_MITIGATION_FULL) { | |
22dd8365 TG |
278 | if (!boot_cpu_has(X86_FEATURE_MD_CLEAR)) |
279 | mds_mitigation = MDS_MITIGATION_VMWERV; | |
d71eb0ce | 280 | |
22dd8365 | 281 | static_branch_enable(&mds_user_clear); |
d71eb0ce | 282 | |
5c14068f JP |
283 | if (!boot_cpu_has(X86_BUG_MSBDS_ONLY) && |
284 | (mds_nosmt || cpu_mitigations_auto_nosmt())) | |
d71eb0ce | 285 | cpu_smt_disable(false); |
bc124170 | 286 | } |
cd5a2aa8 WL |
287 | } |
288 | ||
bc124170 TG |
289 | static int __init mds_cmdline(char *str) |
290 | { | |
291 | if (!boot_cpu_has_bug(X86_BUG_MDS)) | |
292 | return 0; | |
293 | ||
294 | if (!str) | |
295 | return -EINVAL; | |
296 | ||
297 | if (!strcmp(str, "off")) | |
298 | mds_mitigation = MDS_MITIGATION_OFF; | |
299 | else if (!strcmp(str, "full")) | |
300 | mds_mitigation = MDS_MITIGATION_FULL; | |
d71eb0ce JP |
301 | else if (!strcmp(str, "full,nosmt")) { |
302 | mds_mitigation = MDS_MITIGATION_FULL; | |
303 | mds_nosmt = true; | |
304 | } | |
bc124170 TG |
305 | |
306 | return 0; | |
307 | } | |
308 | early_param("mds", mds_cmdline); | |
309 | ||
1b42f017 PG |
310 | #undef pr_fmt |
311 | #define pr_fmt(fmt) "TAA: " fmt | |
312 | ||
72c2ce98 BP |
313 | enum taa_mitigations { |
314 | TAA_MITIGATION_OFF, | |
315 | TAA_MITIGATION_UCODE_NEEDED, | |
316 | TAA_MITIGATION_VERW, | |
317 | TAA_MITIGATION_TSX_DISABLED, | |
318 | }; | |
319 | ||
1b42f017 PG |
320 | /* Default mitigation for TAA-affected CPUs */ |
321 | static enum taa_mitigations taa_mitigation __ro_after_init = TAA_MITIGATION_VERW; | |
322 | static bool taa_nosmt __ro_after_init; | |
323 | ||
324 | static const char * const taa_strings[] = { | |
325 | [TAA_MITIGATION_OFF] = "Vulnerable", | |
326 | [TAA_MITIGATION_UCODE_NEEDED] = "Vulnerable: Clear CPU buffers attempted, no microcode", | |
327 | [TAA_MITIGATION_VERW] = "Mitigation: Clear CPU buffers", | |
328 | [TAA_MITIGATION_TSX_DISABLED] = "Mitigation: TSX disabled", | |
329 | }; | |
330 | ||
331 | static void __init taa_select_mitigation(void) | |
332 | { | |
333 | u64 ia32_cap; | |
334 | ||
335 | if (!boot_cpu_has_bug(X86_BUG_TAA)) { | |
336 | taa_mitigation = TAA_MITIGATION_OFF; | |
337 | return; | |
338 | } | |
339 | ||
340 | /* TSX previously disabled by tsx=off */ | |
341 | if (!boot_cpu_has(X86_FEATURE_RTM)) { | |
342 | taa_mitigation = TAA_MITIGATION_TSX_DISABLED; | |
6a9231bf | 343 | return; |
1b42f017 PG |
344 | } |
345 | ||
346 | if (cpu_mitigations_off()) { | |
347 | taa_mitigation = TAA_MITIGATION_OFF; | |
348 | return; | |
349 | } | |
350 | ||
64870ed1 WL |
351 | /* |
352 | * TAA mitigation via VERW is turned off if both | |
353 | * tsx_async_abort=off and mds=off are specified. | |
354 | */ | |
355 | if (taa_mitigation == TAA_MITIGATION_OFF && | |
356 | mds_mitigation == MDS_MITIGATION_OFF) | |
6a9231bf | 357 | return; |
1b42f017 PG |
358 | |
359 | if (boot_cpu_has(X86_FEATURE_MD_CLEAR)) | |
360 | taa_mitigation = TAA_MITIGATION_VERW; | |
361 | else | |
362 | taa_mitigation = TAA_MITIGATION_UCODE_NEEDED; | |
363 | ||
364 | /* | |
365 | * VERW doesn't clear the CPU buffers when MD_CLEAR=1 and MDS_NO=1. | |
366 | * A microcode update fixes this behavior to clear CPU buffers. It also | |
367 | * adds support for MSR_IA32_TSX_CTRL which is enumerated by the | |
368 | * ARCH_CAP_TSX_CTRL_MSR bit. | |
369 | * | |
370 | * On MDS_NO=1 CPUs if ARCH_CAP_TSX_CTRL_MSR is not set, microcode | |
371 | * update is required. | |
372 | */ | |
373 | ia32_cap = x86_read_arch_cap_msr(); | |
374 | if ( (ia32_cap & ARCH_CAP_MDS_NO) && | |
375 | !(ia32_cap & ARCH_CAP_TSX_CTRL_MSR)) | |
376 | taa_mitigation = TAA_MITIGATION_UCODE_NEEDED; | |
377 | ||
378 | /* | |
379 | * TSX is enabled, select alternate mitigation for TAA which is | |
380 | * the same as MDS. Enable MDS static branch to clear CPU buffers. | |
381 | * | |
382 | * For guests that can't determine whether the correct microcode is | |
383 | * present on host, enable the mitigation for UCODE_NEEDED as well. | |
384 | */ | |
385 | static_branch_enable(&mds_user_clear); | |
386 | ||
387 | if (taa_nosmt || cpu_mitigations_auto_nosmt()) | |
388 | cpu_smt_disable(false); | |
1b42f017 PG |
389 | } |
390 | ||
391 | static int __init tsx_async_abort_parse_cmdline(char *str) | |
392 | { | |
393 | if (!boot_cpu_has_bug(X86_BUG_TAA)) | |
394 | return 0; | |
395 | ||
396 | if (!str) | |
397 | return -EINVAL; | |
398 | ||
399 | if (!strcmp(str, "off")) { | |
400 | taa_mitigation = TAA_MITIGATION_OFF; | |
401 | } else if (!strcmp(str, "full")) { | |
402 | taa_mitigation = TAA_MITIGATION_VERW; | |
403 | } else if (!strcmp(str, "full,nosmt")) { | |
404 | taa_mitigation = TAA_MITIGATION_VERW; | |
405 | taa_nosmt = true; | |
406 | } | |
407 | ||
408 | return 0; | |
409 | } | |
410 | early_param("tsx_async_abort", tsx_async_abort_parse_cmdline); | |
411 | ||
2418c6b1 PG |
412 | #undef pr_fmt |
413 | #define pr_fmt(fmt) "MMIO Stale Data: " fmt | |
414 | ||
415 | enum mmio_mitigations { | |
416 | MMIO_MITIGATION_OFF, | |
417 | MMIO_MITIGATION_UCODE_NEEDED, | |
418 | MMIO_MITIGATION_VERW, | |
419 | }; | |
420 | ||
421 | /* Default mitigation for Processor MMIO Stale Data vulnerabilities */ | |
422 | static enum mmio_mitigations mmio_mitigation __ro_after_init = MMIO_MITIGATION_VERW; | |
423 | static bool mmio_nosmt __ro_after_init = false; | |
424 | ||
425 | static const char * const mmio_strings[] = { | |
426 | [MMIO_MITIGATION_OFF] = "Vulnerable", | |
427 | [MMIO_MITIGATION_UCODE_NEEDED] = "Vulnerable: Clear CPU buffers attempted, no microcode", | |
428 | [MMIO_MITIGATION_VERW] = "Mitigation: Clear CPU buffers", | |
429 | }; | |
430 | ||
431 | static void __init mmio_select_mitigation(void) | |
432 | { | |
433 | u64 ia32_cap; | |
434 | ||
435 | if (!boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA) || | |
436 | cpu_mitigations_off()) { | |
437 | mmio_mitigation = MMIO_MITIGATION_OFF; | |
438 | return; | |
439 | } | |
440 | ||
441 | if (mmio_mitigation == MMIO_MITIGATION_OFF) | |
442 | return; | |
443 | ||
444 | ia32_cap = x86_read_arch_cap_msr(); | |
445 | ||
446 | /* | |
447 | * Enable CPU buffer clear mitigation for host and VMM, if also affected | |
448 | * by MDS or TAA. Otherwise, enable mitigation for VMM only. | |
449 | */ | |
450 | if (boot_cpu_has_bug(X86_BUG_MDS) || (boot_cpu_has_bug(X86_BUG_TAA) && | |
451 | boot_cpu_has(X86_FEATURE_RTM))) | |
452 | static_branch_enable(&mds_user_clear); | |
453 | else | |
454 | static_branch_enable(&mmio_stale_data_clear); | |
455 | ||
92a2794a PG |
456 | /* |
457 | * If Processor-MMIO-Stale-Data bug is present and Fill Buffer data can | |
458 | * be propagated to uncore buffers, clearing the Fill buffers on idle | |
459 | * is required irrespective of SMT state. | |
460 | */ | |
461 | if (!(ia32_cap & ARCH_CAP_FBSDP_NO)) | |
462 | static_branch_enable(&mds_idle_clear); | |
463 | ||
2418c6b1 PG |
464 | /* |
465 | * Check if the system has the right microcode. | |
466 | * | |
467 | * CPU Fill buffer clear mitigation is enumerated by either an explicit | |
468 | * FB_CLEAR or by the presence of both MD_CLEAR and L1D_FLUSH on MDS | |
469 | * affected systems. | |
470 | */ | |
471 | if ((ia32_cap & ARCH_CAP_FB_CLEAR) || | |
472 | (boot_cpu_has(X86_FEATURE_MD_CLEAR) && | |
473 | boot_cpu_has(X86_FEATURE_FLUSH_L1D) && | |
474 | !(ia32_cap & ARCH_CAP_MDS_NO))) | |
475 | mmio_mitigation = MMIO_MITIGATION_VERW; | |
476 | else | |
477 | mmio_mitigation = MMIO_MITIGATION_UCODE_NEEDED; | |
478 | ||
479 | if (mmio_nosmt || cpu_mitigations_auto_nosmt()) | |
480 | cpu_smt_disable(false); | |
481 | } | |
482 | ||
483 | static int __init mmio_stale_data_parse_cmdline(char *str) | |
484 | { | |
485 | if (!boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA)) | |
486 | return 0; | |
487 | ||
488 | if (!str) | |
489 | return -EINVAL; | |
490 | ||
491 | if (!strcmp(str, "off")) { | |
492 | mmio_mitigation = MMIO_MITIGATION_OFF; | |
493 | } else if (!strcmp(str, "full")) { | |
494 | mmio_mitigation = MMIO_MITIGATION_VERW; | |
495 | } else if (!strcmp(str, "full,nosmt")) { | |
496 | mmio_mitigation = MMIO_MITIGATION_VERW; | |
497 | mmio_nosmt = true; | |
498 | } | |
499 | ||
500 | return 0; | |
501 | } | |
502 | early_param("mmio_stale_data", mmio_stale_data_parse_cmdline); | |
503 | ||
6a9231bf PG |
504 | #undef pr_fmt |
505 | #define pr_fmt(fmt) "" fmt | |
506 | ||
507 | static void __init md_clear_update_mitigation(void) | |
508 | { | |
509 | if (cpu_mitigations_off()) | |
510 | return; | |
511 | ||
512 | if (!static_key_enabled(&mds_user_clear)) | |
513 | goto out; | |
514 | ||
515 | /* | |
2418c6b1 PG |
516 | * mds_user_clear is now enabled. Update MDS, TAA and MMIO Stale Data |
517 | * mitigation, if necessary. | |
6a9231bf PG |
518 | */ |
519 | if (mds_mitigation == MDS_MITIGATION_OFF && | |
520 | boot_cpu_has_bug(X86_BUG_MDS)) { | |
521 | mds_mitigation = MDS_MITIGATION_FULL; | |
522 | mds_select_mitigation(); | |
523 | } | |
2418c6b1 PG |
524 | if (taa_mitigation == TAA_MITIGATION_OFF && |
525 | boot_cpu_has_bug(X86_BUG_TAA)) { | |
526 | taa_mitigation = TAA_MITIGATION_VERW; | |
527 | taa_select_mitigation(); | |
528 | } | |
529 | if (mmio_mitigation == MMIO_MITIGATION_OFF && | |
530 | boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA)) { | |
531 | mmio_mitigation = MMIO_MITIGATION_VERW; | |
532 | mmio_select_mitigation(); | |
533 | } | |
6a9231bf PG |
534 | out: |
535 | if (boot_cpu_has_bug(X86_BUG_MDS)) | |
536 | pr_info("MDS: %s\n", mds_strings[mds_mitigation]); | |
537 | if (boot_cpu_has_bug(X86_BUG_TAA)) | |
538 | pr_info("TAA: %s\n", taa_strings[taa_mitigation]); | |
2418c6b1 PG |
539 | if (boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA)) |
540 | pr_info("MMIO Stale Data: %s\n", mmio_strings[mmio_mitigation]); | |
6a9231bf PG |
541 | } |
542 | ||
b9bc1fb8 PG |
543 | static void __init md_clear_select_mitigation(void) |
544 | { | |
545 | mds_select_mitigation(); | |
546 | taa_select_mitigation(); | |
547 | mmio_select_mitigation(); | |
548 | ||
549 | /* | |
550 | * As MDS, TAA and MMIO Stale Data mitigations are inter-related, update | |
551 | * and print their mitigation after MDS, TAA and MMIO Stale Data | |
552 | * mitigation selection is done. | |
553 | */ | |
554 | md_clear_update_mitigation(); | |
555 | } | |
556 | ||
7e5b3c26 MG |
557 | #undef pr_fmt |
558 | #define pr_fmt(fmt) "SRBDS: " fmt | |
559 | ||
560 | enum srbds_mitigations { | |
561 | SRBDS_MITIGATION_OFF, | |
562 | SRBDS_MITIGATION_UCODE_NEEDED, | |
563 | SRBDS_MITIGATION_FULL, | |
564 | SRBDS_MITIGATION_TSX_OFF, | |
565 | SRBDS_MITIGATION_HYPERVISOR, | |
566 | }; | |
567 | ||
568 | static enum srbds_mitigations srbds_mitigation __ro_after_init = SRBDS_MITIGATION_FULL; | |
569 | ||
570 | static const char * const srbds_strings[] = { | |
571 | [SRBDS_MITIGATION_OFF] = "Vulnerable", | |
572 | [SRBDS_MITIGATION_UCODE_NEEDED] = "Vulnerable: No microcode", | |
573 | [SRBDS_MITIGATION_FULL] = "Mitigation: Microcode", | |
574 | [SRBDS_MITIGATION_TSX_OFF] = "Mitigation: TSX disabled", | |
575 | [SRBDS_MITIGATION_HYPERVISOR] = "Unknown: Dependent on hypervisor status", | |
576 | }; | |
577 | ||
578 | static bool srbds_off; | |
579 | ||
580 | void update_srbds_msr(void) | |
581 | { | |
582 | u64 mcu_ctrl; | |
583 | ||
584 | if (!boot_cpu_has_bug(X86_BUG_SRBDS)) | |
585 | return; | |
586 | ||
587 | if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) | |
588 | return; | |
589 | ||
590 | if (srbds_mitigation == SRBDS_MITIGATION_UCODE_NEEDED) | |
591 | return; | |
592 | ||
593 | rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl); | |
594 | ||
595 | switch (srbds_mitigation) { | |
596 | case SRBDS_MITIGATION_OFF: | |
597 | case SRBDS_MITIGATION_TSX_OFF: | |
598 | mcu_ctrl |= RNGDS_MITG_DIS; | |
599 | break; | |
600 | case SRBDS_MITIGATION_FULL: | |
601 | mcu_ctrl &= ~RNGDS_MITG_DIS; | |
602 | break; | |
603 | default: | |
604 | break; | |
605 | } | |
606 | ||
607 | wrmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl); | |
608 | } | |
609 | ||
610 | static void __init srbds_select_mitigation(void) | |
611 | { | |
612 | u64 ia32_cap; | |
613 | ||
614 | if (!boot_cpu_has_bug(X86_BUG_SRBDS)) | |
615 | return; | |
616 | ||
617 | /* | |
ee855cd4 PG |
618 | * Check to see if this is one of the MDS_NO systems supporting TSX that |
619 | * are only exposed to SRBDS when TSX is enabled or when CPU is affected | |
620 | * by Processor MMIO Stale Data vulnerability. | |
7e5b3c26 MG |
621 | */ |
622 | ia32_cap = x86_read_arch_cap_msr(); | |
ee855cd4 PG |
623 | if ((ia32_cap & ARCH_CAP_MDS_NO) && !boot_cpu_has(X86_FEATURE_RTM) && |
624 | !boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA)) | |
7e5b3c26 MG |
625 | srbds_mitigation = SRBDS_MITIGATION_TSX_OFF; |
626 | else if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) | |
627 | srbds_mitigation = SRBDS_MITIGATION_HYPERVISOR; | |
628 | else if (!boot_cpu_has(X86_FEATURE_SRBDS_CTRL)) | |
629 | srbds_mitigation = SRBDS_MITIGATION_UCODE_NEEDED; | |
630 | else if (cpu_mitigations_off() || srbds_off) | |
631 | srbds_mitigation = SRBDS_MITIGATION_OFF; | |
632 | ||
633 | update_srbds_msr(); | |
634 | pr_info("%s\n", srbds_strings[srbds_mitigation]); | |
635 | } | |
636 | ||
637 | static int __init srbds_parse_cmdline(char *str) | |
638 | { | |
639 | if (!str) | |
640 | return -EINVAL; | |
641 | ||
642 | if (!boot_cpu_has_bug(X86_BUG_SRBDS)) | |
643 | return 0; | |
644 | ||
645 | srbds_off = !strcmp(str, "off"); | |
646 | return 0; | |
647 | } | |
648 | early_param("srbds", srbds_parse_cmdline); | |
649 | ||
b5f06f64 BS |
650 | #undef pr_fmt |
651 | #define pr_fmt(fmt) "L1D Flush : " fmt | |
652 | ||
653 | enum l1d_flush_mitigations { | |
654 | L1D_FLUSH_OFF = 0, | |
655 | L1D_FLUSH_ON, | |
656 | }; | |
657 | ||
658 | static enum l1d_flush_mitigations l1d_flush_mitigation __initdata = L1D_FLUSH_OFF; | |
659 | ||
660 | static void __init l1d_flush_select_mitigation(void) | |
661 | { | |
662 | if (!l1d_flush_mitigation || !boot_cpu_has(X86_FEATURE_FLUSH_L1D)) | |
663 | return; | |
664 | ||
665 | static_branch_enable(&switch_mm_cond_l1d_flush); | |
666 | pr_info("Conditional flush on switch_mm() enabled\n"); | |
667 | } | |
668 | ||
669 | static int __init l1d_flush_parse_cmdline(char *str) | |
670 | { | |
671 | if (!strcmp(str, "on")) | |
672 | l1d_flush_mitigation = L1D_FLUSH_ON; | |
673 | ||
674 | return 0; | |
675 | } | |
676 | early_param("l1d_flush", l1d_flush_parse_cmdline); | |
677 | ||
a2059825 JP |
678 | #undef pr_fmt |
679 | #define pr_fmt(fmt) "Spectre V1 : " fmt | |
680 | ||
681 | enum spectre_v1_mitigation { | |
682 | SPECTRE_V1_MITIGATION_NONE, | |
683 | SPECTRE_V1_MITIGATION_AUTO, | |
684 | }; | |
685 | ||
686 | static enum spectre_v1_mitigation spectre_v1_mitigation __ro_after_init = | |
687 | SPECTRE_V1_MITIGATION_AUTO; | |
688 | ||
689 | static const char * const spectre_v1_strings[] = { | |
690 | [SPECTRE_V1_MITIGATION_NONE] = "Vulnerable: __user pointer sanitization and usercopy barriers only; no swapgs barriers", | |
691 | [SPECTRE_V1_MITIGATION_AUTO] = "Mitigation: usercopy/swapgs barriers and __user pointer sanitization", | |
692 | }; | |
693 | ||
a2059825 JP |
694 | /* |
695 | * Does SMAP provide full mitigation against speculative kernel access to | |
696 | * userspace? | |
697 | */ | |
698 | static bool smap_works_speculatively(void) | |
699 | { | |
700 | if (!boot_cpu_has(X86_FEATURE_SMAP)) | |
701 | return false; | |
702 | ||
703 | /* | |
704 | * On CPUs which are vulnerable to Meltdown, SMAP does not | |
705 | * prevent speculative access to user data in the L1 cache. | |
706 | * Consider SMAP to be non-functional as a mitigation on these | |
707 | * CPUs. | |
708 | */ | |
709 | if (boot_cpu_has(X86_BUG_CPU_MELTDOWN)) | |
710 | return false; | |
711 | ||
712 | return true; | |
713 | } | |
714 | ||
715 | static void __init spectre_v1_select_mitigation(void) | |
716 | { | |
717 | if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V1) || cpu_mitigations_off()) { | |
718 | spectre_v1_mitigation = SPECTRE_V1_MITIGATION_NONE; | |
719 | return; | |
720 | } | |
721 | ||
722 | if (spectre_v1_mitigation == SPECTRE_V1_MITIGATION_AUTO) { | |
723 | /* | |
724 | * With Spectre v1, a user can speculatively control either | |
725 | * path of a conditional swapgs with a user-controlled GS | |
726 | * value. The mitigation is to add lfences to both code paths. | |
727 | * | |
728 | * If FSGSBASE is enabled, the user can put a kernel address in | |
729 | * GS, in which case SMAP provides no protection. | |
730 | * | |
a2059825 JP |
731 | * If FSGSBASE is disabled, the user can only put a user space |
732 | * address in GS. That makes an attack harder, but still | |
733 | * possible if there's no SMAP protection. | |
734 | */ | |
978e1342 TL |
735 | if (boot_cpu_has(X86_FEATURE_FSGSBASE) || |
736 | !smap_works_speculatively()) { | |
a2059825 JP |
737 | /* |
738 | * Mitigation can be provided from SWAPGS itself or | |
739 | * PTI as the CR3 write in the Meltdown mitigation | |
740 | * is serializing. | |
741 | * | |
f36cf386 TG |
742 | * If neither is there, mitigate with an LFENCE to |
743 | * stop speculation through swapgs. | |
a2059825 | 744 | */ |
f36cf386 TG |
745 | if (boot_cpu_has_bug(X86_BUG_SWAPGS) && |
746 | !boot_cpu_has(X86_FEATURE_PTI)) | |
a2059825 JP |
747 | setup_force_cpu_cap(X86_FEATURE_FENCE_SWAPGS_USER); |
748 | ||
749 | /* | |
750 | * Enable lfences in the kernel entry (non-swapgs) | |
751 | * paths, to prevent user entry from speculatively | |
752 | * skipping swapgs. | |
753 | */ | |
754 | setup_force_cpu_cap(X86_FEATURE_FENCE_SWAPGS_KERNEL); | |
755 | } | |
756 | } | |
757 | ||
758 | pr_info("%s\n", spectre_v1_strings[spectre_v1_mitigation]); | |
759 | } | |
760 | ||
761 | static int __init nospectre_v1_cmdline(char *str) | |
762 | { | |
763 | spectre_v1_mitigation = SPECTRE_V1_MITIGATION_NONE; | |
764 | return 0; | |
765 | } | |
766 | early_param("nospectre_v1", nospectre_v1_cmdline); | |
767 | ||
ae5afe50 PZ |
768 | static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init = |
769 | SPECTRE_V2_NONE; | |
770 | ||
8ed18e15 AC |
771 | #undef pr_fmt |
772 | #define pr_fmt(fmt) "RETBleed: " fmt | |
773 | ||
774 | enum retbleed_mitigation { | |
775 | RETBLEED_MITIGATION_NONE, | |
776 | RETBLEED_MITIGATION_UNRET, | |
7b3fa544 | 777 | RETBLEED_MITIGATION_IBPB, |
ae5afe50 PZ |
778 | RETBLEED_MITIGATION_IBRS, |
779 | RETBLEED_MITIGATION_EIBRS, | |
8ed18e15 AC |
780 | }; |
781 | ||
782 | enum retbleed_mitigation_cmd { | |
783 | RETBLEED_CMD_OFF, | |
784 | RETBLEED_CMD_AUTO, | |
785 | RETBLEED_CMD_UNRET, | |
7b3fa544 | 786 | RETBLEED_CMD_IBPB, |
8ed18e15 AC |
787 | }; |
788 | ||
789 | const char * const retbleed_strings[] = { | |
790 | [RETBLEED_MITIGATION_NONE] = "Vulnerable", | |
791 | [RETBLEED_MITIGATION_UNRET] = "Mitigation: untrained return thunk", | |
7b3fa544 | 792 | [RETBLEED_MITIGATION_IBPB] = "Mitigation: IBPB", |
ae5afe50 PZ |
793 | [RETBLEED_MITIGATION_IBRS] = "Mitigation: IBRS", |
794 | [RETBLEED_MITIGATION_EIBRS] = "Mitigation: Enhanced IBRS", | |
8ed18e15 AC |
795 | }; |
796 | ||
797 | static enum retbleed_mitigation retbleed_mitigation __ro_after_init = | |
798 | RETBLEED_MITIGATION_NONE; | |
799 | static enum retbleed_mitigation_cmd retbleed_cmd __ro_after_init = | |
800 | RETBLEED_CMD_AUTO; | |
801 | ||
d8bc226a KP |
802 | static int __ro_after_init retbleed_nosmt = false; |
803 | ||
8ed18e15 AC |
804 | static int __init retbleed_parse_cmdline(char *str) |
805 | { | |
806 | if (!str) | |
807 | return -EINVAL; | |
808 | ||
d8bc226a KP |
809 | while (str) { |
810 | char *next = strchr(str, ','); | |
811 | if (next) { | |
812 | *next = 0; | |
813 | next++; | |
814 | } | |
815 | ||
816 | if (!strcmp(str, "off")) { | |
817 | retbleed_cmd = RETBLEED_CMD_OFF; | |
818 | } else if (!strcmp(str, "auto")) { | |
819 | retbleed_cmd = RETBLEED_CMD_AUTO; | |
820 | } else if (!strcmp(str, "unret")) { | |
821 | retbleed_cmd = RETBLEED_CMD_UNRET; | |
7b3fa544 PZ |
822 | } else if (!strcmp(str, "ibpb")) { |
823 | retbleed_cmd = RETBLEED_CMD_IBPB; | |
d8bc226a KP |
824 | } else if (!strcmp(str, "nosmt")) { |
825 | retbleed_nosmt = true; | |
826 | } else { | |
827 | pr_err("Ignoring unknown retbleed option (%s).", str); | |
828 | } | |
829 | ||
830 | str = next; | |
831 | } | |
8ed18e15 AC |
832 | |
833 | return 0; | |
834 | } | |
835 | early_param("retbleed", retbleed_parse_cmdline); | |
836 | ||
837 | #define RETBLEED_UNTRAIN_MSG "WARNING: BTB untrained return thunk mitigation is only effective on AMD/Hygon!\n" | |
ae5afe50 | 838 | #define RETBLEED_INTEL_MSG "WARNING: Spectre v2 mitigation leaves CPU vulnerable to RETBleed attacks, data leaks possible!\n" |
8ed18e15 AC |
839 | |
840 | static void __init retbleed_select_mitigation(void) | |
841 | { | |
7b3fa544 PZ |
842 | bool mitigate_smt = false; |
843 | ||
8ed18e15 AC |
844 | if (!boot_cpu_has_bug(X86_BUG_RETBLEED) || cpu_mitigations_off()) |
845 | return; | |
846 | ||
847 | switch (retbleed_cmd) { | |
848 | case RETBLEED_CMD_OFF: | |
849 | return; | |
850 | ||
851 | case RETBLEED_CMD_UNRET: | |
cbd355e4 PZ |
852 | if (IS_ENABLED(CONFIG_CPU_UNRET_ENTRY)) { |
853 | retbleed_mitigation = RETBLEED_MITIGATION_UNRET; | |
854 | } else { | |
855 | pr_err("WARNING: kernel not compiled with CPU_UNRET_ENTRY.\n"); | |
856 | goto do_cmd_auto; | |
857 | } | |
8ed18e15 AC |
858 | break; |
859 | ||
7b3fa544 | 860 | case RETBLEED_CMD_IBPB: |
fb1dd6d4 TLSC |
861 | if (!boot_cpu_has(X86_FEATURE_IBPB)) { |
862 | pr_err("WARNING: CPU does not support IBPB.\n"); | |
863 | goto do_cmd_auto; | |
864 | } else if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY)) { | |
cbd355e4 PZ |
865 | retbleed_mitigation = RETBLEED_MITIGATION_IBPB; |
866 | } else { | |
867 | pr_err("WARNING: kernel not compiled with CPU_IBPB_ENTRY.\n"); | |
868 | goto do_cmd_auto; | |
869 | } | |
7b3fa544 PZ |
870 | break; |
871 | ||
cbd355e4 | 872 | do_cmd_auto: |
8ed18e15 AC |
873 | case RETBLEED_CMD_AUTO: |
874 | default: | |
8ed18e15 | 875 | if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || |
cbd355e4 PZ |
876 | boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) { |
877 | if (IS_ENABLED(CONFIG_CPU_UNRET_ENTRY)) | |
878 | retbleed_mitigation = RETBLEED_MITIGATION_UNRET; | |
fb1dd6d4 | 879 | else if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY) && boot_cpu_has(X86_FEATURE_IBPB)) |
cbd355e4 PZ |
880 | retbleed_mitigation = RETBLEED_MITIGATION_IBPB; |
881 | } | |
ae5afe50 PZ |
882 | |
883 | /* | |
c25e6ff8 JP |
884 | * The Intel mitigation (IBRS or eIBRS) was already selected in |
885 | * spectre_v2_select_mitigation(). 'retbleed_mitigation' will | |
886 | * be set accordingly below. | |
ae5afe50 PZ |
887 | */ |
888 | ||
8ed18e15 AC |
889 | break; |
890 | } | |
891 | ||
892 | switch (retbleed_mitigation) { | |
893 | case RETBLEED_MITIGATION_UNRET: | |
8ed18e15 AC |
894 | setup_force_cpu_cap(X86_FEATURE_RETHUNK); |
895 | setup_force_cpu_cap(X86_FEATURE_UNRET); | |
896 | ||
897 | if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD && | |
898 | boot_cpu_data.x86_vendor != X86_VENDOR_HYGON) | |
899 | pr_err(RETBLEED_UNTRAIN_MSG); | |
7b3fa544 PZ |
900 | |
901 | mitigate_smt = true; | |
902 | break; | |
903 | ||
904 | case RETBLEED_MITIGATION_IBPB: | |
7b3fa544 PZ |
905 | setup_force_cpu_cap(X86_FEATURE_ENTRY_IBPB); |
906 | mitigate_smt = true; | |
8ed18e15 AC |
907 | break; |
908 | ||
909 | default: | |
910 | break; | |
911 | } | |
912 | ||
7b3fa544 PZ |
913 | if (mitigate_smt && !boot_cpu_has(X86_FEATURE_STIBP) && |
914 | (retbleed_nosmt || cpu_mitigations_auto_nosmt())) | |
915 | cpu_smt_disable(false); | |
916 | ||
ae5afe50 PZ |
917 | /* |
918 | * Let IBRS trump all on Intel without affecting the effects of the | |
919 | * retbleed= cmdline option. | |
920 | */ | |
921 | if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) { | |
922 | switch (spectre_v2_enabled) { | |
923 | case SPECTRE_V2_IBRS: | |
924 | retbleed_mitigation = RETBLEED_MITIGATION_IBRS; | |
925 | break; | |
926 | case SPECTRE_V2_EIBRS: | |
927 | case SPECTRE_V2_EIBRS_RETPOLINE: | |
928 | case SPECTRE_V2_EIBRS_LFENCE: | |
929 | retbleed_mitigation = RETBLEED_MITIGATION_EIBRS; | |
930 | break; | |
931 | default: | |
932 | pr_err(RETBLEED_INTEL_MSG); | |
933 | } | |
934 | } | |
935 | ||
8ed18e15 AC |
936 | pr_info("%s\n", retbleed_strings[retbleed_mitigation]); |
937 | } | |
938 | ||
15d6b7aa TG |
939 | #undef pr_fmt |
940 | #define pr_fmt(fmt) "Spectre V2 : " fmt | |
941 | ||
21998a35 AS |
942 | static enum spectre_v2_user_mitigation spectre_v2_user_stibp __ro_after_init = |
943 | SPECTRE_V2_USER_NONE; | |
944 | static enum spectre_v2_user_mitigation spectre_v2_user_ibpb __ro_after_init = | |
fa1202ef TG |
945 | SPECTRE_V2_USER_NONE; |
946 | ||
e4f35891 | 947 | #ifdef CONFIG_RETPOLINE |
e383095c TG |
948 | static bool spectre_v2_bad_module; |
949 | ||
caf7501a AK |
950 | bool retpoline_module_ok(bool has_retpoline) |
951 | { | |
952 | if (spectre_v2_enabled == SPECTRE_V2_NONE || has_retpoline) | |
953 | return true; | |
954 | ||
e698dcdf | 955 | pr_err("System may be vulnerable to spectre v2\n"); |
caf7501a AK |
956 | spectre_v2_bad_module = true; |
957 | return false; | |
958 | } | |
e383095c TG |
959 | |
960 | static inline const char *spectre_v2_module_string(void) | |
961 | { | |
962 | return spectre_v2_bad_module ? " - vulnerable module loaded" : ""; | |
963 | } | |
964 | #else | |
965 | static inline const char *spectre_v2_module_string(void) { return ""; } | |
caf7501a | 966 | #endif |
da285121 | 967 | |
92cf97b2 | 968 | #define SPECTRE_V2_LFENCE_MSG "WARNING: LFENCE mitigation is not recommended for this CPU, data leaks possible!\n" |
534fcc9a | 969 | #define SPECTRE_V2_EIBRS_EBPF_MSG "WARNING: Unprivileged eBPF is enabled with eIBRS on, data leaks possible via Spectre v2 BHB attacks!\n" |
810643a7 | 970 | #define SPECTRE_V2_EIBRS_LFENCE_EBPF_SMT_MSG "WARNING: Unprivileged eBPF is enabled with eIBRS+LFENCE mitigation and SMT, data leaks possible via Spectre v2 BHB attacks!\n" |
534fcc9a JP |
971 | |
972 | #ifdef CONFIG_BPF_SYSCALL | |
973 | void unpriv_ebpf_notify(int new_state) | |
974 | { | |
810643a7 JP |
975 | if (new_state) |
976 | return; | |
977 | ||
978 | /* Unprivileged eBPF is enabled */ | |
979 | ||
980 | switch (spectre_v2_enabled) { | |
981 | case SPECTRE_V2_EIBRS: | |
534fcc9a | 982 | pr_err(SPECTRE_V2_EIBRS_EBPF_MSG); |
810643a7 JP |
983 | break; |
984 | case SPECTRE_V2_EIBRS_LFENCE: | |
985 | if (sched_smt_active()) | |
986 | pr_err(SPECTRE_V2_EIBRS_LFENCE_EBPF_SMT_MSG); | |
987 | break; | |
988 | default: | |
989 | break; | |
990 | } | |
534fcc9a JP |
991 | } |
992 | #endif | |
993 | ||
da285121 DW |
994 | static inline bool match_option(const char *arg, int arglen, const char *opt) |
995 | { | |
996 | int len = strlen(opt); | |
997 | ||
998 | return len == arglen && !strncmp(arg, opt, len); | |
999 | } | |
1000 | ||
15d6b7aa TG |
1001 | /* The kernel command line selection for spectre v2 */ |
1002 | enum spectre_v2_mitigation_cmd { | |
1003 | SPECTRE_V2_CMD_NONE, | |
1004 | SPECTRE_V2_CMD_AUTO, | |
1005 | SPECTRE_V2_CMD_FORCE, | |
1006 | SPECTRE_V2_CMD_RETPOLINE, | |
1007 | SPECTRE_V2_CMD_RETPOLINE_GENERIC, | |
a24bd1da | 1008 | SPECTRE_V2_CMD_RETPOLINE_LFENCE, |
a94faf3f PZ |
1009 | SPECTRE_V2_CMD_EIBRS, |
1010 | SPECTRE_V2_CMD_EIBRS_RETPOLINE, | |
1011 | SPECTRE_V2_CMD_EIBRS_LFENCE, | |
ddf9f0cd | 1012 | SPECTRE_V2_CMD_IBRS, |
15d6b7aa TG |
1013 | }; |
1014 | ||
fa1202ef TG |
1015 | enum spectre_v2_user_cmd { |
1016 | SPECTRE_V2_USER_CMD_NONE, | |
1017 | SPECTRE_V2_USER_CMD_AUTO, | |
1018 | SPECTRE_V2_USER_CMD_FORCE, | |
7cc765a6 | 1019 | SPECTRE_V2_USER_CMD_PRCTL, |
55a97402 | 1020 | SPECTRE_V2_USER_CMD_PRCTL_IBPB, |
6b3e64c2 | 1021 | SPECTRE_V2_USER_CMD_SECCOMP, |
55a97402 | 1022 | SPECTRE_V2_USER_CMD_SECCOMP_IBPB, |
fa1202ef TG |
1023 | }; |
1024 | ||
1025 | static const char * const spectre_v2_user_strings[] = { | |
20c3a2c3 TL |
1026 | [SPECTRE_V2_USER_NONE] = "User space: Vulnerable", |
1027 | [SPECTRE_V2_USER_STRICT] = "User space: Mitigation: STIBP protection", | |
1028 | [SPECTRE_V2_USER_STRICT_PREFERRED] = "User space: Mitigation: STIBP always-on protection", | |
1029 | [SPECTRE_V2_USER_PRCTL] = "User space: Mitigation: STIBP via prctl", | |
1030 | [SPECTRE_V2_USER_SECCOMP] = "User space: Mitigation: STIBP via seccomp and prctl", | |
fa1202ef TG |
1031 | }; |
1032 | ||
1033 | static const struct { | |
1034 | const char *option; | |
1035 | enum spectre_v2_user_cmd cmd; | |
1036 | bool secure; | |
1de7edbb | 1037 | } v2_user_options[] __initconst = { |
55a97402 TG |
1038 | { "auto", SPECTRE_V2_USER_CMD_AUTO, false }, |
1039 | { "off", SPECTRE_V2_USER_CMD_NONE, false }, | |
1040 | { "on", SPECTRE_V2_USER_CMD_FORCE, true }, | |
1041 | { "prctl", SPECTRE_V2_USER_CMD_PRCTL, false }, | |
1042 | { "prctl,ibpb", SPECTRE_V2_USER_CMD_PRCTL_IBPB, false }, | |
1043 | { "seccomp", SPECTRE_V2_USER_CMD_SECCOMP, false }, | |
1044 | { "seccomp,ibpb", SPECTRE_V2_USER_CMD_SECCOMP_IBPB, false }, | |
fa1202ef TG |
1045 | }; |
1046 | ||
1047 | static void __init spec_v2_user_print_cond(const char *reason, bool secure) | |
1048 | { | |
1049 | if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2) != secure) | |
1050 | pr_info("spectre_v2_user=%s forced on command line.\n", reason); | |
1051 | } | |
1052 | ||
b4e79f4b PZ |
1053 | static __ro_after_init enum spectre_v2_mitigation_cmd spectre_v2_cmd; |
1054 | ||
fa1202ef | 1055 | static enum spectre_v2_user_cmd __init |
b4e79f4b | 1056 | spectre_v2_parse_user_cmdline(void) |
fa1202ef TG |
1057 | { |
1058 | char arg[20]; | |
1059 | int ret, i; | |
1060 | ||
b4e79f4b | 1061 | switch (spectre_v2_cmd) { |
fa1202ef TG |
1062 | case SPECTRE_V2_CMD_NONE: |
1063 | return SPECTRE_V2_USER_CMD_NONE; | |
1064 | case SPECTRE_V2_CMD_FORCE: | |
1065 | return SPECTRE_V2_USER_CMD_FORCE; | |
1066 | default: | |
1067 | break; | |
1068 | } | |
1069 | ||
1070 | ret = cmdline_find_option(boot_command_line, "spectre_v2_user", | |
1071 | arg, sizeof(arg)); | |
1072 | if (ret < 0) | |
1073 | return SPECTRE_V2_USER_CMD_AUTO; | |
1074 | ||
1075 | for (i = 0; i < ARRAY_SIZE(v2_user_options); i++) { | |
1076 | if (match_option(arg, ret, v2_user_options[i].option)) { | |
1077 | spec_v2_user_print_cond(v2_user_options[i].option, | |
1078 | v2_user_options[i].secure); | |
1079 | return v2_user_options[i].cmd; | |
1080 | } | |
1081 | } | |
1082 | ||
1083 | pr_err("Unknown user space protection option (%s). Switching to AUTO select\n", arg); | |
1084 | return SPECTRE_V2_USER_CMD_AUTO; | |
1085 | } | |
1086 | ||
ddf9f0cd | 1087 | static inline bool spectre_v2_in_ibrs_mode(enum spectre_v2_mitigation mode) |
a94faf3f | 1088 | { |
ddf9f0cd PG |
1089 | return mode == SPECTRE_V2_IBRS || |
1090 | mode == SPECTRE_V2_EIBRS || | |
1091 | mode == SPECTRE_V2_EIBRS_RETPOLINE || | |
1092 | mode == SPECTRE_V2_EIBRS_LFENCE; | |
a94faf3f PZ |
1093 | } |
1094 | ||
fa1202ef | 1095 | static void __init |
b4e79f4b | 1096 | spectre_v2_user_select_mitigation(void) |
fa1202ef TG |
1097 | { |
1098 | enum spectre_v2_user_mitigation mode = SPECTRE_V2_USER_NONE; | |
1099 | bool smt_possible = IS_ENABLED(CONFIG_SMP); | |
55a97402 | 1100 | enum spectre_v2_user_cmd cmd; |
fa1202ef TG |
1101 | |
1102 | if (!boot_cpu_has(X86_FEATURE_IBPB) && !boot_cpu_has(X86_FEATURE_STIBP)) | |
1103 | return; | |
1104 | ||
1105 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED || | |
1106 | cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
1107 | smt_possible = false; | |
1108 | ||
b4e79f4b | 1109 | cmd = spectre_v2_parse_user_cmdline(); |
55a97402 | 1110 | switch (cmd) { |
fa1202ef TG |
1111 | case SPECTRE_V2_USER_CMD_NONE: |
1112 | goto set_mode; | |
1113 | case SPECTRE_V2_USER_CMD_FORCE: | |
1114 | mode = SPECTRE_V2_USER_STRICT; | |
1115 | break; | |
7cc765a6 | 1116 | case SPECTRE_V2_USER_CMD_PRCTL: |
55a97402 | 1117 | case SPECTRE_V2_USER_CMD_PRCTL_IBPB: |
7cc765a6 TG |
1118 | mode = SPECTRE_V2_USER_PRCTL; |
1119 | break; | |
6b3e64c2 TG |
1120 | case SPECTRE_V2_USER_CMD_AUTO: |
1121 | case SPECTRE_V2_USER_CMD_SECCOMP: | |
55a97402 | 1122 | case SPECTRE_V2_USER_CMD_SECCOMP_IBPB: |
6b3e64c2 TG |
1123 | if (IS_ENABLED(CONFIG_SECCOMP)) |
1124 | mode = SPECTRE_V2_USER_SECCOMP; | |
1125 | else | |
1126 | mode = SPECTRE_V2_USER_PRCTL; | |
1127 | break; | |
fa1202ef TG |
1128 | } |
1129 | ||
1130 | /* Initialize Indirect Branch Prediction Barrier */ | |
1131 | if (boot_cpu_has(X86_FEATURE_IBPB)) { | |
1132 | setup_force_cpu_cap(X86_FEATURE_USE_IBPB); | |
4c71a2b6 | 1133 | |
33fc379d | 1134 | spectre_v2_user_ibpb = mode; |
55a97402 TG |
1135 | switch (cmd) { |
1136 | case SPECTRE_V2_USER_CMD_FORCE: | |
1137 | case SPECTRE_V2_USER_CMD_PRCTL_IBPB: | |
1138 | case SPECTRE_V2_USER_CMD_SECCOMP_IBPB: | |
4c71a2b6 | 1139 | static_branch_enable(&switch_mm_always_ibpb); |
33fc379d | 1140 | spectre_v2_user_ibpb = SPECTRE_V2_USER_STRICT; |
4c71a2b6 | 1141 | break; |
55a97402 TG |
1142 | case SPECTRE_V2_USER_CMD_PRCTL: |
1143 | case SPECTRE_V2_USER_CMD_AUTO: | |
1144 | case SPECTRE_V2_USER_CMD_SECCOMP: | |
7cc765a6 TG |
1145 | static_branch_enable(&switch_mm_cond_ibpb); |
1146 | break; | |
4c71a2b6 TG |
1147 | default: |
1148 | break; | |
1149 | } | |
1150 | ||
1151 | pr_info("mitigation: Enabling %s Indirect Branch Prediction Barrier\n", | |
55a97402 TG |
1152 | static_key_enabled(&switch_mm_always_ibpb) ? |
1153 | "always-on" : "conditional"); | |
fa1202ef TG |
1154 | } |
1155 | ||
21998a35 | 1156 | /* |
ddf9f0cd PG |
1157 | * If no STIBP, IBRS or enhanced IBRS is enabled, or SMT impossible, |
1158 | * STIBP is not required. | |
21998a35 | 1159 | */ |
a5ce9f2b BP |
1160 | if (!boot_cpu_has(X86_FEATURE_STIBP) || |
1161 | !smt_possible || | |
ddf9f0cd | 1162 | spectre_v2_in_ibrs_mode(spectre_v2_enabled)) |
fa1202ef TG |
1163 | return; |
1164 | ||
7cc765a6 | 1165 | /* |
21998a35 AS |
1166 | * At this point, an STIBP mode other than "off" has been set. |
1167 | * If STIBP support is not being forced, check if STIBP always-on | |
1168 | * is preferred. | |
7cc765a6 | 1169 | */ |
21998a35 AS |
1170 | if (mode != SPECTRE_V2_USER_STRICT && |
1171 | boot_cpu_has(X86_FEATURE_AMD_STIBP_ALWAYS_ON)) | |
1172 | mode = SPECTRE_V2_USER_STRICT_PREFERRED; | |
1173 | ||
d8bc226a KP |
1174 | if (retbleed_mitigation == RETBLEED_MITIGATION_UNRET) { |
1175 | if (mode != SPECTRE_V2_USER_STRICT && | |
1176 | mode != SPECTRE_V2_USER_STRICT_PREFERRED) | |
1177 | pr_info("Selecting STIBP always-on mode to complement retbleed mitigation'\n"); | |
1178 | mode = SPECTRE_V2_USER_STRICT_PREFERRED; | |
1179 | } | |
1180 | ||
21998a35 AS |
1181 | spectre_v2_user_stibp = mode; |
1182 | ||
fa1202ef | 1183 | set_mode: |
21998a35 | 1184 | pr_info("%s\n", spectre_v2_user_strings[mode]); |
fa1202ef TG |
1185 | } |
1186 | ||
8770709f | 1187 | static const char * const spectre_v2_strings[] = { |
15d6b7aa | 1188 | [SPECTRE_V2_NONE] = "Vulnerable", |
a24bd1da PZI |
1189 | [SPECTRE_V2_RETPOLINE] = "Mitigation: Retpolines", |
1190 | [SPECTRE_V2_LFENCE] = "Mitigation: LFENCE", | |
a94faf3f PZ |
1191 | [SPECTRE_V2_EIBRS] = "Mitigation: Enhanced IBRS", |
1192 | [SPECTRE_V2_EIBRS_LFENCE] = "Mitigation: Enhanced IBRS + LFENCE", | |
1193 | [SPECTRE_V2_EIBRS_RETPOLINE] = "Mitigation: Enhanced IBRS + Retpolines", | |
ddf9f0cd | 1194 | [SPECTRE_V2_IBRS] = "Mitigation: IBRS", |
15d6b7aa TG |
1195 | }; |
1196 | ||
9005c683 KA |
1197 | static const struct { |
1198 | const char *option; | |
1199 | enum spectre_v2_mitigation_cmd cmd; | |
1200 | bool secure; | |
1de7edbb | 1201 | } mitigation_options[] __initconst = { |
15d6b7aa TG |
1202 | { "off", SPECTRE_V2_CMD_NONE, false }, |
1203 | { "on", SPECTRE_V2_CMD_FORCE, true }, | |
1204 | { "retpoline", SPECTRE_V2_CMD_RETPOLINE, false }, | |
a24bd1da PZI |
1205 | { "retpoline,amd", SPECTRE_V2_CMD_RETPOLINE_LFENCE, false }, |
1206 | { "retpoline,lfence", SPECTRE_V2_CMD_RETPOLINE_LFENCE, false }, | |
15d6b7aa | 1207 | { "retpoline,generic", SPECTRE_V2_CMD_RETPOLINE_GENERIC, false }, |
a94faf3f PZ |
1208 | { "eibrs", SPECTRE_V2_CMD_EIBRS, false }, |
1209 | { "eibrs,lfence", SPECTRE_V2_CMD_EIBRS_LFENCE, false }, | |
1210 | { "eibrs,retpoline", SPECTRE_V2_CMD_EIBRS_RETPOLINE, false }, | |
15d6b7aa | 1211 | { "auto", SPECTRE_V2_CMD_AUTO, false }, |
ddf9f0cd | 1212 | { "ibrs", SPECTRE_V2_CMD_IBRS, false }, |
9005c683 KA |
1213 | }; |
1214 | ||
495d470e | 1215 | static void __init spec_v2_print_cond(const char *reason, bool secure) |
15d6b7aa | 1216 | { |
495d470e | 1217 | if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2) != secure) |
15d6b7aa TG |
1218 | pr_info("%s selected on command line.\n", reason); |
1219 | } | |
1220 | ||
da285121 DW |
1221 | static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void) |
1222 | { | |
15d6b7aa | 1223 | enum spectre_v2_mitigation_cmd cmd = SPECTRE_V2_CMD_AUTO; |
da285121 | 1224 | char arg[20]; |
9005c683 | 1225 | int ret, i; |
9005c683 | 1226 | |
d68be4c4 JP |
1227 | if (cmdline_find_option_bool(boot_command_line, "nospectre_v2") || |
1228 | cpu_mitigations_off()) | |
9005c683 | 1229 | return SPECTRE_V2_CMD_NONE; |
9005c683 | 1230 | |
24848509 TC |
1231 | ret = cmdline_find_option(boot_command_line, "spectre_v2", arg, sizeof(arg)); |
1232 | if (ret < 0) | |
1233 | return SPECTRE_V2_CMD_AUTO; | |
1234 | ||
1235 | for (i = 0; i < ARRAY_SIZE(mitigation_options); i++) { | |
1236 | if (!match_option(arg, ret, mitigation_options[i].option)) | |
1237 | continue; | |
1238 | cmd = mitigation_options[i].cmd; | |
1239 | break; | |
1240 | } | |
1241 | ||
1242 | if (i >= ARRAY_SIZE(mitigation_options)) { | |
1243 | pr_err("unknown option (%s). Switching to AUTO select\n", arg); | |
1244 | return SPECTRE_V2_CMD_AUTO; | |
da285121 DW |
1245 | } |
1246 | ||
9005c683 | 1247 | if ((cmd == SPECTRE_V2_CMD_RETPOLINE || |
a24bd1da | 1248 | cmd == SPECTRE_V2_CMD_RETPOLINE_LFENCE || |
a94faf3f PZ |
1249 | cmd == SPECTRE_V2_CMD_RETPOLINE_GENERIC || |
1250 | cmd == SPECTRE_V2_CMD_EIBRS_LFENCE || | |
1251 | cmd == SPECTRE_V2_CMD_EIBRS_RETPOLINE) && | |
9005c683 | 1252 | !IS_ENABLED(CONFIG_RETPOLINE)) { |
a94faf3f PZ |
1253 | pr_err("%s selected but not compiled in. Switching to AUTO select\n", |
1254 | mitigation_options[i].option); | |
1255 | return SPECTRE_V2_CMD_AUTO; | |
1256 | } | |
1257 | ||
1258 | if ((cmd == SPECTRE_V2_CMD_EIBRS || | |
1259 | cmd == SPECTRE_V2_CMD_EIBRS_LFENCE || | |
1260 | cmd == SPECTRE_V2_CMD_EIBRS_RETPOLINE) && | |
1261 | !boot_cpu_has(X86_FEATURE_IBRS_ENHANCED)) { | |
1262 | pr_err("%s selected but CPU doesn't have eIBRS. Switching to AUTO select\n", | |
1263 | mitigation_options[i].option); | |
da285121 | 1264 | return SPECTRE_V2_CMD_AUTO; |
9005c683 KA |
1265 | } |
1266 | ||
a94faf3f PZ |
1267 | if ((cmd == SPECTRE_V2_CMD_RETPOLINE_LFENCE || |
1268 | cmd == SPECTRE_V2_CMD_EIBRS_LFENCE) && | |
a24bd1da | 1269 | !boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) { |
a94faf3f PZ |
1270 | pr_err("%s selected, but CPU doesn't have a serializing LFENCE. Switching to AUTO select\n", |
1271 | mitigation_options[i].option); | |
a24bd1da PZI |
1272 | return SPECTRE_V2_CMD_AUTO; |
1273 | } | |
1274 | ||
cbd355e4 PZ |
1275 | if (cmd == SPECTRE_V2_CMD_IBRS && !IS_ENABLED(CONFIG_CPU_IBRS_ENTRY)) { |
1276 | pr_err("%s selected but not compiled in. Switching to AUTO select\n", | |
1277 | mitigation_options[i].option); | |
1278 | return SPECTRE_V2_CMD_AUTO; | |
1279 | } | |
1280 | ||
ddf9f0cd PG |
1281 | if (cmd == SPECTRE_V2_CMD_IBRS && boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) { |
1282 | pr_err("%s selected but not Intel CPU. Switching to AUTO select\n", | |
1283 | mitigation_options[i].option); | |
1284 | return SPECTRE_V2_CMD_AUTO; | |
1285 | } | |
1286 | ||
1287 | if (cmd == SPECTRE_V2_CMD_IBRS && !boot_cpu_has(X86_FEATURE_IBRS)) { | |
1288 | pr_err("%s selected but CPU doesn't have IBRS. Switching to AUTO select\n", | |
1289 | mitigation_options[i].option); | |
1290 | return SPECTRE_V2_CMD_AUTO; | |
1291 | } | |
1292 | ||
1293 | if (cmd == SPECTRE_V2_CMD_IBRS && boot_cpu_has(X86_FEATURE_XENPV)) { | |
1294 | pr_err("%s selected but running as XenPV guest. Switching to AUTO select\n", | |
1295 | mitigation_options[i].option); | |
1296 | return SPECTRE_V2_CMD_AUTO; | |
1297 | } | |
1298 | ||
495d470e TG |
1299 | spec_v2_print_cond(mitigation_options[i].option, |
1300 | mitigation_options[i].secure); | |
9005c683 | 1301 | return cmd; |
da285121 DW |
1302 | } |
1303 | ||
a94faf3f PZ |
1304 | static enum spectre_v2_mitigation __init spectre_v2_select_retpoline(void) |
1305 | { | |
1306 | if (!IS_ENABLED(CONFIG_RETPOLINE)) { | |
1307 | pr_err("Kernel not compiled with retpoline; no mitigation available!"); | |
1308 | return SPECTRE_V2_NONE; | |
1309 | } | |
1310 | ||
a94faf3f PZ |
1311 | return SPECTRE_V2_RETPOLINE; |
1312 | } | |
1313 | ||
da285121 DW |
1314 | static void __init spectre_v2_select_mitigation(void) |
1315 | { | |
1316 | enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline(); | |
1317 | enum spectre_v2_mitigation mode = SPECTRE_V2_NONE; | |
1318 | ||
1319 | /* | |
1320 | * If the CPU is not affected and the command line mode is NONE or AUTO | |
1321 | * then nothing to do. | |
1322 | */ | |
1323 | if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2) && | |
1324 | (cmd == SPECTRE_V2_CMD_NONE || cmd == SPECTRE_V2_CMD_AUTO)) | |
1325 | return; | |
1326 | ||
1327 | switch (cmd) { | |
1328 | case SPECTRE_V2_CMD_NONE: | |
1329 | return; | |
1330 | ||
1331 | case SPECTRE_V2_CMD_FORCE: | |
da285121 | 1332 | case SPECTRE_V2_CMD_AUTO: |
706d5168 | 1333 | if (boot_cpu_has(X86_FEATURE_IBRS_ENHANCED)) { |
a94faf3f PZ |
1334 | mode = SPECTRE_V2_EIBRS; |
1335 | break; | |
706d5168 | 1336 | } |
a94faf3f | 1337 | |
cbd355e4 PZ |
1338 | if (IS_ENABLED(CONFIG_CPU_IBRS_ENTRY) && |
1339 | boot_cpu_has_bug(X86_BUG_RETBLEED) && | |
ddf9f0cd PG |
1340 | retbleed_cmd != RETBLEED_CMD_OFF && |
1341 | boot_cpu_has(X86_FEATURE_IBRS) && | |
1342 | boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) { | |
1343 | mode = SPECTRE_V2_IBRS; | |
1344 | break; | |
1345 | } | |
1346 | ||
a94faf3f | 1347 | mode = spectre_v2_select_retpoline(); |
9471eee9 | 1348 | break; |
a94faf3f | 1349 | |
a24bd1da | 1350 | case SPECTRE_V2_CMD_RETPOLINE_LFENCE: |
92cf97b2 | 1351 | pr_err(SPECTRE_V2_LFENCE_MSG); |
a94faf3f | 1352 | mode = SPECTRE_V2_LFENCE; |
da285121 | 1353 | break; |
a94faf3f | 1354 | |
da285121 | 1355 | case SPECTRE_V2_CMD_RETPOLINE_GENERIC: |
a94faf3f | 1356 | mode = SPECTRE_V2_RETPOLINE; |
da285121 | 1357 | break; |
a94faf3f | 1358 | |
da285121 | 1359 | case SPECTRE_V2_CMD_RETPOLINE: |
a94faf3f PZ |
1360 | mode = spectre_v2_select_retpoline(); |
1361 | break; | |
1362 | ||
ddf9f0cd PG |
1363 | case SPECTRE_V2_CMD_IBRS: |
1364 | mode = SPECTRE_V2_IBRS; | |
1365 | break; | |
1366 | ||
a94faf3f PZ |
1367 | case SPECTRE_V2_CMD_EIBRS: |
1368 | mode = SPECTRE_V2_EIBRS; | |
1369 | break; | |
1370 | ||
1371 | case SPECTRE_V2_CMD_EIBRS_LFENCE: | |
1372 | mode = SPECTRE_V2_EIBRS_LFENCE; | |
1373 | break; | |
1374 | ||
1375 | case SPECTRE_V2_CMD_EIBRS_RETPOLINE: | |
1376 | mode = SPECTRE_V2_EIBRS_RETPOLINE; | |
da285121 DW |
1377 | break; |
1378 | } | |
da285121 | 1379 | |
534fcc9a JP |
1380 | if (mode == SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled()) |
1381 | pr_err(SPECTRE_V2_EIBRS_EBPF_MSG); | |
1382 | ||
ddf9f0cd | 1383 | if (spectre_v2_in_ibrs_mode(mode)) { |
a94faf3f | 1384 | x86_spec_ctrl_base |= SPEC_CTRL_IBRS; |
1d800213 | 1385 | write_spec_ctrl_current(x86_spec_ctrl_base, true); |
a94faf3f PZ |
1386 | } |
1387 | ||
1388 | switch (mode) { | |
1389 | case SPECTRE_V2_NONE: | |
1390 | case SPECTRE_V2_EIBRS: | |
1391 | break; | |
1392 | ||
ddf9f0cd PG |
1393 | case SPECTRE_V2_IBRS: |
1394 | setup_force_cpu_cap(X86_FEATURE_KERNEL_IBRS); | |
1395 | break; | |
1396 | ||
a94faf3f PZ |
1397 | case SPECTRE_V2_LFENCE: |
1398 | case SPECTRE_V2_EIBRS_LFENCE: | |
a24bd1da | 1399 | setup_force_cpu_cap(X86_FEATURE_RETPOLINE_LFENCE); |
a94faf3f PZ |
1400 | fallthrough; |
1401 | ||
1402 | case SPECTRE_V2_RETPOLINE: | |
1403 | case SPECTRE_V2_EIBRS_RETPOLINE: | |
da285121 | 1404 | setup_force_cpu_cap(X86_FEATURE_RETPOLINE); |
a94faf3f | 1405 | break; |
da285121 DW |
1406 | } |
1407 | ||
1408 | spectre_v2_enabled = mode; | |
1409 | pr_info("%s\n", spectre_v2_strings[mode]); | |
c995efd5 DW |
1410 | |
1411 | /* | |
7bb0b4d7 JP |
1412 | * If Spectre v2 protection has been enabled, fill the RSB during a |
1413 | * context switch. In general there are two types of RSB attacks | |
1414 | * across context switches, for which the CALLs/RETs may be unbalanced. | |
c995efd5 | 1415 | * |
7bb0b4d7 JP |
1416 | * 1) RSB underflow |
1417 | * | |
1418 | * Some Intel parts have "bottomless RSB". When the RSB is empty, | |
1419 | * speculated return targets may come from the branch predictor, | |
1420 | * which could have a user-poisoned BTB or BHB entry. | |
1421 | * | |
1422 | * AMD has it even worse: *all* returns are speculated from the BTB, | |
1423 | * regardless of the state of the RSB. | |
1424 | * | |
1425 | * When IBRS or eIBRS is enabled, the "user -> kernel" attack | |
1426 | * scenario is mitigated by the IBRS branch prediction isolation | |
1427 | * properties, so the RSB buffer filling wouldn't be necessary to | |
1428 | * protect against this type of attack. | |
1429 | * | |
1430 | * The "user -> user" attack scenario is mitigated by RSB filling. | |
1431 | * | |
1432 | * 2) Poisoned RSB entry | |
1433 | * | |
1434 | * If the 'next' in-kernel return stack is shorter than 'prev', | |
1435 | * 'next' could be tricked into speculating with a user-poisoned RSB | |
1436 | * entry. | |
1437 | * | |
1438 | * The "user -> kernel" attack scenario is mitigated by SMEP and | |
1439 | * eIBRS. | |
1440 | * | |
1441 | * The "user -> user" scenario, also known as SpectreBHB, requires | |
1442 | * RSB clearing. | |
1443 | * | |
1444 | * So to mitigate all cases, unconditionally fill RSB on context | |
1445 | * switches. | |
1446 | * | |
1447 | * FIXME: Is this pointless for retbleed-affected AMD? | |
c995efd5 | 1448 | */ |
fdf82a78 JK |
1449 | setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW); |
1450 | pr_info("Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch\n"); | |
20ffa1ca | 1451 | |
7bb0b4d7 JP |
1452 | /* |
1453 | * Similar to context switches, there are two types of RSB attacks | |
1454 | * after vmexit: | |
1455 | * | |
1456 | * 1) RSB underflow | |
1457 | * | |
1458 | * 2) Poisoned RSB entry | |
1459 | * | |
1460 | * When retpoline is enabled, both are mitigated by filling/clearing | |
1461 | * the RSB. | |
1462 | * | |
1463 | * When IBRS is enabled, while #1 would be mitigated by the IBRS branch | |
1464 | * prediction isolation protections, RSB still needs to be cleared | |
1465 | * because of #2. Note that SMEP provides no protection here, unlike | |
1466 | * user-space-poisoned RSB entries. | |
1467 | * | |
1468 | * eIBRS, on the other hand, has RSB-poisoning protections, so it | |
1469 | * doesn't need RSB clearing after vmexit. | |
1470 | */ | |
1471 | if (boot_cpu_has(X86_FEATURE_RETPOLINE) || | |
1472 | boot_cpu_has(X86_FEATURE_KERNEL_IBRS)) | |
1473 | setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT); | |
1474 | ||
dd84441a | 1475 | /* |
ddf9f0cd PG |
1476 | * Retpoline protects the kernel, but doesn't protect firmware. IBRS |
1477 | * and Enhanced IBRS protect firmware too, so enable IBRS around | |
1478 | * firmware calls only when IBRS / Enhanced IBRS aren't otherwise | |
1479 | * enabled. | |
706d5168 SP |
1480 | * |
1481 | * Use "mode" to check Enhanced IBRS instead of boot_cpu_has(), because | |
1482 | * the user might select retpoline on the kernel command line and if | |
1483 | * the CPU supports Enhanced IBRS, kernel might un-intentionally not | |
1484 | * enable IBRS around firmware calls. | |
dd84441a | 1485 | */ |
ddf9f0cd | 1486 | if (boot_cpu_has(X86_FEATURE_IBRS) && !spectre_v2_in_ibrs_mode(mode)) { |
dd84441a DW |
1487 | setup_force_cpu_cap(X86_FEATURE_USE_IBRS_FW); |
1488 | pr_info("Enabling Restricted Speculation for firmware calls\n"); | |
1489 | } | |
53c613fe | 1490 | |
fa1202ef | 1491 | /* Set up IBPB and STIBP depending on the general spectre V2 command */ |
b4e79f4b | 1492 | spectre_v2_cmd = cmd; |
da285121 DW |
1493 | } |
1494 | ||
6893a959 | 1495 | static void update_stibp_msr(void * __unused) |
15d6b7aa | 1496 | { |
82758882 JP |
1497 | u64 val = spec_ctrl_current() | (x86_spec_ctrl_base & SPEC_CTRL_STIBP); |
1498 | write_spec_ctrl_current(val, true); | |
15d6b7aa TG |
1499 | } |
1500 | ||
6893a959 TG |
1501 | /* Update x86_spec_ctrl_base in case SMT state changed. */ |
1502 | static void update_stibp_strict(void) | |
15d6b7aa | 1503 | { |
6893a959 TG |
1504 | u64 mask = x86_spec_ctrl_base & ~SPEC_CTRL_STIBP; |
1505 | ||
1506 | if (sched_smt_active()) | |
1507 | mask |= SPEC_CTRL_STIBP; | |
1508 | ||
1509 | if (mask == x86_spec_ctrl_base) | |
1510 | return; | |
1511 | ||
1512 | pr_info("Update user space SMT mitigation: STIBP %s\n", | |
1513 | mask & SPEC_CTRL_STIBP ? "always-on" : "off"); | |
1514 | x86_spec_ctrl_base = mask; | |
1515 | on_each_cpu(update_stibp_msr, NULL, 1); | |
15d6b7aa TG |
1516 | } |
1517 | ||
7cc765a6 TG |
1518 | /* Update the static key controlling the evaluation of TIF_SPEC_IB */ |
1519 | static void update_indir_branch_cond(void) | |
1520 | { | |
1521 | if (sched_smt_active()) | |
1522 | static_branch_enable(&switch_to_cond_stibp); | |
1523 | else | |
1524 | static_branch_disable(&switch_to_cond_stibp); | |
1525 | } | |
1526 | ||
39226ef0 JP |
1527 | #undef pr_fmt |
1528 | #define pr_fmt(fmt) fmt | |
1529 | ||
bc124170 TG |
1530 | /* Update the static key controlling the MDS CPU buffer clear in idle */ |
1531 | static void update_mds_branch_idle(void) | |
1532 | { | |
92a2794a PG |
1533 | u64 ia32_cap = x86_read_arch_cap_msr(); |
1534 | ||
bc124170 TG |
1535 | /* |
1536 | * Enable the idle clearing if SMT is active on CPUs which are | |
1537 | * affected only by MSBDS and not any other MDS variant. | |
1538 | * | |
1539 | * The other variants cannot be mitigated when SMT is enabled, so | |
1540 | * clearing the buffers on idle just to prevent the Store Buffer | |
1541 | * repartitioning leak would be a window dressing exercise. | |
1542 | */ | |
1543 | if (!boot_cpu_has_bug(X86_BUG_MSBDS_ONLY)) | |
1544 | return; | |
1545 | ||
92a2794a | 1546 | if (sched_smt_active()) { |
bc124170 | 1547 | static_branch_enable(&mds_idle_clear); |
92a2794a PG |
1548 | } else if (mmio_mitigation == MMIO_MITIGATION_OFF || |
1549 | (ia32_cap & ARCH_CAP_FBSDP_NO)) { | |
bc124170 | 1550 | static_branch_disable(&mds_idle_clear); |
92a2794a | 1551 | } |
bc124170 TG |
1552 | } |
1553 | ||
39226ef0 | 1554 | #define MDS_MSG_SMT "MDS CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html for more details.\n" |
1b42f017 | 1555 | #define TAA_MSG_SMT "TAA CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/tsx_async_abort.html for more details.\n" |
db343f8b | 1556 | #define MMIO_MSG_SMT "MMIO Stale Data CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/processor_mmio_stale_data.html for more details.\n" |
39226ef0 | 1557 | |
9c92374b | 1558 | void cpu_bugs_smt_update(void) |
15d6b7aa | 1559 | { |
15d6b7aa TG |
1560 | mutex_lock(&spec_ctrl_mutex); |
1561 | ||
810643a7 JP |
1562 | if (sched_smt_active() && unprivileged_ebpf_enabled() && |
1563 | spectre_v2_enabled == SPECTRE_V2_EIBRS_LFENCE) | |
1564 | pr_warn_once(SPECTRE_V2_EIBRS_LFENCE_EBPF_SMT_MSG); | |
1565 | ||
21998a35 | 1566 | switch (spectre_v2_user_stibp) { |
6893a959 TG |
1567 | case SPECTRE_V2_USER_NONE: |
1568 | break; | |
1569 | case SPECTRE_V2_USER_STRICT: | |
20c3a2c3 | 1570 | case SPECTRE_V2_USER_STRICT_PREFERRED: |
6893a959 TG |
1571 | update_stibp_strict(); |
1572 | break; | |
9137bb27 | 1573 | case SPECTRE_V2_USER_PRCTL: |
6b3e64c2 | 1574 | case SPECTRE_V2_USER_SECCOMP: |
7cc765a6 | 1575 | update_indir_branch_cond(); |
9137bb27 | 1576 | break; |
15d6b7aa | 1577 | } |
6893a959 | 1578 | |
22dd8365 TG |
1579 | switch (mds_mitigation) { |
1580 | case MDS_MITIGATION_FULL: | |
1581 | case MDS_MITIGATION_VMWERV: | |
39226ef0 JP |
1582 | if (sched_smt_active() && !boot_cpu_has(X86_BUG_MSBDS_ONLY)) |
1583 | pr_warn_once(MDS_MSG_SMT); | |
bc124170 | 1584 | update_mds_branch_idle(); |
22dd8365 TG |
1585 | break; |
1586 | case MDS_MITIGATION_OFF: | |
1587 | break; | |
1588 | } | |
bc124170 | 1589 | |
1b42f017 PG |
1590 | switch (taa_mitigation) { |
1591 | case TAA_MITIGATION_VERW: | |
1592 | case TAA_MITIGATION_UCODE_NEEDED: | |
1593 | if (sched_smt_active()) | |
1594 | pr_warn_once(TAA_MSG_SMT); | |
1595 | break; | |
1596 | case TAA_MITIGATION_TSX_DISABLED: | |
1597 | case TAA_MITIGATION_OFF: | |
1598 | break; | |
1599 | } | |
1600 | ||
db343f8b JP |
1601 | switch (mmio_mitigation) { |
1602 | case MMIO_MITIGATION_VERW: | |
1603 | case MMIO_MITIGATION_UCODE_NEEDED: | |
1604 | if (sched_smt_active()) | |
1605 | pr_warn_once(MMIO_MSG_SMT); | |
1606 | break; | |
1607 | case MMIO_MITIGATION_OFF: | |
1608 | break; | |
1609 | } | |
1610 | ||
15d6b7aa TG |
1611 | mutex_unlock(&spec_ctrl_mutex); |
1612 | } | |
1613 | ||
24f7fc83 KRW |
1614 | #undef pr_fmt |
1615 | #define pr_fmt(fmt) "Speculative Store Bypass: " fmt | |
1616 | ||
f9544b2b | 1617 | static enum ssb_mitigation ssb_mode __ro_after_init = SPEC_STORE_BYPASS_NONE; |
24f7fc83 KRW |
1618 | |
1619 | /* The kernel command line selection */ | |
1620 | enum ssb_mitigation_cmd { | |
1621 | SPEC_STORE_BYPASS_CMD_NONE, | |
1622 | SPEC_STORE_BYPASS_CMD_AUTO, | |
1623 | SPEC_STORE_BYPASS_CMD_ON, | |
a73ec77e | 1624 | SPEC_STORE_BYPASS_CMD_PRCTL, |
f21b53b2 | 1625 | SPEC_STORE_BYPASS_CMD_SECCOMP, |
24f7fc83 KRW |
1626 | }; |
1627 | ||
8770709f | 1628 | static const char * const ssb_strings[] = { |
24f7fc83 | 1629 | [SPEC_STORE_BYPASS_NONE] = "Vulnerable", |
a73ec77e | 1630 | [SPEC_STORE_BYPASS_DISABLE] = "Mitigation: Speculative Store Bypass disabled", |
f21b53b2 KC |
1631 | [SPEC_STORE_BYPASS_PRCTL] = "Mitigation: Speculative Store Bypass disabled via prctl", |
1632 | [SPEC_STORE_BYPASS_SECCOMP] = "Mitigation: Speculative Store Bypass disabled via prctl and seccomp", | |
24f7fc83 KRW |
1633 | }; |
1634 | ||
1635 | static const struct { | |
1636 | const char *option; | |
1637 | enum ssb_mitigation_cmd cmd; | |
1de7edbb | 1638 | } ssb_mitigation_options[] __initconst = { |
f21b53b2 KC |
1639 | { "auto", SPEC_STORE_BYPASS_CMD_AUTO }, /* Platform decides */ |
1640 | { "on", SPEC_STORE_BYPASS_CMD_ON }, /* Disable Speculative Store Bypass */ | |
1641 | { "off", SPEC_STORE_BYPASS_CMD_NONE }, /* Don't touch Speculative Store Bypass */ | |
1642 | { "prctl", SPEC_STORE_BYPASS_CMD_PRCTL }, /* Disable Speculative Store Bypass via prctl */ | |
1643 | { "seccomp", SPEC_STORE_BYPASS_CMD_SECCOMP }, /* Disable Speculative Store Bypass via prctl and seccomp */ | |
24f7fc83 KRW |
1644 | }; |
1645 | ||
1646 | static enum ssb_mitigation_cmd __init ssb_parse_cmdline(void) | |
1647 | { | |
1648 | enum ssb_mitigation_cmd cmd = SPEC_STORE_BYPASS_CMD_AUTO; | |
1649 | char arg[20]; | |
1650 | int ret, i; | |
1651 | ||
d68be4c4 JP |
1652 | if (cmdline_find_option_bool(boot_command_line, "nospec_store_bypass_disable") || |
1653 | cpu_mitigations_off()) { | |
24f7fc83 KRW |
1654 | return SPEC_STORE_BYPASS_CMD_NONE; |
1655 | } else { | |
1656 | ret = cmdline_find_option(boot_command_line, "spec_store_bypass_disable", | |
1657 | arg, sizeof(arg)); | |
1658 | if (ret < 0) | |
1659 | return SPEC_STORE_BYPASS_CMD_AUTO; | |
1660 | ||
1661 | for (i = 0; i < ARRAY_SIZE(ssb_mitigation_options); i++) { | |
1662 | if (!match_option(arg, ret, ssb_mitigation_options[i].option)) | |
1663 | continue; | |
1664 | ||
1665 | cmd = ssb_mitigation_options[i].cmd; | |
1666 | break; | |
1667 | } | |
1668 | ||
1669 | if (i >= ARRAY_SIZE(ssb_mitigation_options)) { | |
1670 | pr_err("unknown option (%s). Switching to AUTO select\n", arg); | |
1671 | return SPEC_STORE_BYPASS_CMD_AUTO; | |
1672 | } | |
1673 | } | |
1674 | ||
1675 | return cmd; | |
1676 | } | |
1677 | ||
d66d8ff3 | 1678 | static enum ssb_mitigation __init __ssb_select_mitigation(void) |
24f7fc83 KRW |
1679 | { |
1680 | enum ssb_mitigation mode = SPEC_STORE_BYPASS_NONE; | |
1681 | enum ssb_mitigation_cmd cmd; | |
1682 | ||
9f65fb29 | 1683 | if (!boot_cpu_has(X86_FEATURE_SSBD)) |
24f7fc83 KRW |
1684 | return mode; |
1685 | ||
1686 | cmd = ssb_parse_cmdline(); | |
1687 | if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS) && | |
1688 | (cmd == SPEC_STORE_BYPASS_CMD_NONE || | |
1689 | cmd == SPEC_STORE_BYPASS_CMD_AUTO)) | |
1690 | return mode; | |
1691 | ||
1692 | switch (cmd) { | |
1693 | case SPEC_STORE_BYPASS_CMD_AUTO: | |
f21b53b2 KC |
1694 | case SPEC_STORE_BYPASS_CMD_SECCOMP: |
1695 | /* | |
1696 | * Choose prctl+seccomp as the default mode if seccomp is | |
1697 | * enabled. | |
1698 | */ | |
1699 | if (IS_ENABLED(CONFIG_SECCOMP)) | |
1700 | mode = SPEC_STORE_BYPASS_SECCOMP; | |
1701 | else | |
1702 | mode = SPEC_STORE_BYPASS_PRCTL; | |
a73ec77e | 1703 | break; |
24f7fc83 KRW |
1704 | case SPEC_STORE_BYPASS_CMD_ON: |
1705 | mode = SPEC_STORE_BYPASS_DISABLE; | |
1706 | break; | |
a73ec77e TG |
1707 | case SPEC_STORE_BYPASS_CMD_PRCTL: |
1708 | mode = SPEC_STORE_BYPASS_PRCTL; | |
1709 | break; | |
24f7fc83 KRW |
1710 | case SPEC_STORE_BYPASS_CMD_NONE: |
1711 | break; | |
1712 | } | |
1713 | ||
77243971 KRW |
1714 | /* |
1715 | * We have three CPU feature flags that are in play here: | |
1716 | * - X86_BUG_SPEC_STORE_BYPASS - CPU is susceptible. | |
9f65fb29 | 1717 | * - X86_FEATURE_SSBD - CPU is able to turn off speculative store bypass |
77243971 KRW |
1718 | * - X86_FEATURE_SPEC_STORE_BYPASS_DISABLE - engage the mitigation |
1719 | */ | |
a73ec77e | 1720 | if (mode == SPEC_STORE_BYPASS_DISABLE) { |
24f7fc83 | 1721 | setup_force_cpu_cap(X86_FEATURE_SPEC_STORE_BYPASS_DISABLE); |
77243971 | 1722 | /* |
6ac2f49e KRW |
1723 | * Intel uses the SPEC CTRL MSR Bit(2) for this, while AMD may |
1724 | * use a completely different MSR and bit dependent on family. | |
77243971 | 1725 | */ |
612bc3b3 TL |
1726 | if (!static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) && |
1727 | !static_cpu_has(X86_FEATURE_AMD_SSBD)) { | |
108fab4b | 1728 | x86_amd_ssb_disable(); |
612bc3b3 | 1729 | } else { |
9f65fb29 | 1730 | x86_spec_ctrl_base |= SPEC_CTRL_SSBD; |
1d800213 | 1731 | write_spec_ctrl_current(x86_spec_ctrl_base, true); |
77243971 KRW |
1732 | } |
1733 | } | |
1734 | ||
24f7fc83 KRW |
1735 | return mode; |
1736 | } | |
1737 | ||
ffed645e | 1738 | static void ssb_select_mitigation(void) |
24f7fc83 KRW |
1739 | { |
1740 | ssb_mode = __ssb_select_mitigation(); | |
1741 | ||
1742 | if (boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS)) | |
1743 | pr_info("%s\n", ssb_strings[ssb_mode]); | |
1744 | } | |
1745 | ||
da285121 | 1746 | #undef pr_fmt |
f21b53b2 | 1747 | #define pr_fmt(fmt) "Speculation prctl: " fmt |
da285121 | 1748 | |
6d991ba5 | 1749 | static void task_update_spec_tif(struct task_struct *tsk) |
a73ec77e | 1750 | { |
6d991ba5 TG |
1751 | /* Force the update of the real TIF bits */ |
1752 | set_tsk_thread_flag(tsk, TIF_SPEC_FORCE_UPDATE); | |
e6da8bb6 TG |
1753 | |
1754 | /* | |
1755 | * Immediately update the speculation control MSRs for the current | |
1756 | * task, but for a non-current task delay setting the CPU | |
1757 | * mitigation until it is scheduled next. | |
1758 | * | |
1759 | * This can only happen for SECCOMP mitigation. For PRCTL it's | |
1760 | * always the current task. | |
1761 | */ | |
6d991ba5 | 1762 | if (tsk == current) |
e6da8bb6 TG |
1763 | speculation_ctrl_update_current(); |
1764 | } | |
1765 | ||
e893bb1b BS |
1766 | static int l1d_flush_prctl_set(struct task_struct *task, unsigned long ctrl) |
1767 | { | |
1768 | ||
1769 | if (!static_branch_unlikely(&switch_mm_cond_l1d_flush)) | |
1770 | return -EPERM; | |
1771 | ||
1772 | switch (ctrl) { | |
1773 | case PR_SPEC_ENABLE: | |
1774 | set_ti_thread_flag(&task->thread_info, TIF_SPEC_L1D_FLUSH); | |
1775 | return 0; | |
1776 | case PR_SPEC_DISABLE: | |
1777 | clear_ti_thread_flag(&task->thread_info, TIF_SPEC_L1D_FLUSH); | |
1778 | return 0; | |
1779 | default: | |
1780 | return -ERANGE; | |
1781 | } | |
1782 | } | |
1783 | ||
e6da8bb6 TG |
1784 | static int ssb_prctl_set(struct task_struct *task, unsigned long ctrl) |
1785 | { | |
f21b53b2 KC |
1786 | if (ssb_mode != SPEC_STORE_BYPASS_PRCTL && |
1787 | ssb_mode != SPEC_STORE_BYPASS_SECCOMP) | |
a73ec77e TG |
1788 | return -ENXIO; |
1789 | ||
356e4bff TG |
1790 | switch (ctrl) { |
1791 | case PR_SPEC_ENABLE: | |
1792 | /* If speculation is force disabled, enable is not allowed */ | |
1793 | if (task_spec_ssb_force_disable(task)) | |
1794 | return -EPERM; | |
1795 | task_clear_spec_ssb_disable(task); | |
71368af9 | 1796 | task_clear_spec_ssb_noexec(task); |
6d991ba5 | 1797 | task_update_spec_tif(task); |
356e4bff TG |
1798 | break; |
1799 | case PR_SPEC_DISABLE: | |
1800 | task_set_spec_ssb_disable(task); | |
71368af9 | 1801 | task_clear_spec_ssb_noexec(task); |
6d991ba5 | 1802 | task_update_spec_tif(task); |
356e4bff TG |
1803 | break; |
1804 | case PR_SPEC_FORCE_DISABLE: | |
1805 | task_set_spec_ssb_disable(task); | |
1806 | task_set_spec_ssb_force_disable(task); | |
71368af9 WL |
1807 | task_clear_spec_ssb_noexec(task); |
1808 | task_update_spec_tif(task); | |
1809 | break; | |
1810 | case PR_SPEC_DISABLE_NOEXEC: | |
1811 | if (task_spec_ssb_force_disable(task)) | |
1812 | return -EPERM; | |
1813 | task_set_spec_ssb_disable(task); | |
1814 | task_set_spec_ssb_noexec(task); | |
6d991ba5 | 1815 | task_update_spec_tif(task); |
356e4bff TG |
1816 | break; |
1817 | default: | |
1818 | return -ERANGE; | |
1819 | } | |
a73ec77e TG |
1820 | return 0; |
1821 | } | |
1822 | ||
1978b3a5 AM |
1823 | static bool is_spec_ib_user_controlled(void) |
1824 | { | |
1825 | return spectre_v2_user_ibpb == SPECTRE_V2_USER_PRCTL || | |
1826 | spectre_v2_user_ibpb == SPECTRE_V2_USER_SECCOMP || | |
1827 | spectre_v2_user_stibp == SPECTRE_V2_USER_PRCTL || | |
1828 | spectre_v2_user_stibp == SPECTRE_V2_USER_SECCOMP; | |
1829 | } | |
1830 | ||
9137bb27 TG |
1831 | static int ib_prctl_set(struct task_struct *task, unsigned long ctrl) |
1832 | { | |
1833 | switch (ctrl) { | |
1834 | case PR_SPEC_ENABLE: | |
21998a35 AS |
1835 | if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE && |
1836 | spectre_v2_user_stibp == SPECTRE_V2_USER_NONE) | |
9137bb27 | 1837 | return 0; |
1978b3a5 | 1838 | |
9137bb27 | 1839 | /* |
1978b3a5 AM |
1840 | * With strict mode for both IBPB and STIBP, the instruction |
1841 | * code paths avoid checking this task flag and instead, | |
1842 | * unconditionally run the instruction. However, STIBP and IBPB | |
1843 | * are independent and either can be set to conditionally | |
1844 | * enabled regardless of the mode of the other. | |
1845 | * | |
1846 | * If either is set to conditional, allow the task flag to be | |
1847 | * updated, unless it was force-disabled by a previous prctl | |
1848 | * call. Currently, this is possible on an AMD CPU which has the | |
1849 | * feature X86_FEATURE_AMD_STIBP_ALWAYS_ON. In this case, if the | |
1850 | * kernel is booted with 'spectre_v2_user=seccomp', then | |
1851 | * spectre_v2_user_ibpb == SPECTRE_V2_USER_SECCOMP and | |
1852 | * spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED. | |
9137bb27 | 1853 | */ |
1978b3a5 | 1854 | if (!is_spec_ib_user_controlled() || |
4d8df8cb | 1855 | task_spec_ib_force_disable(task)) |
9137bb27 | 1856 | return -EPERM; |
1978b3a5 | 1857 | |
9137bb27 TG |
1858 | task_clear_spec_ib_disable(task); |
1859 | task_update_spec_tif(task); | |
1860 | break; | |
1861 | case PR_SPEC_DISABLE: | |
1862 | case PR_SPEC_FORCE_DISABLE: | |
1863 | /* | |
1864 | * Indirect branch speculation is always allowed when | |
1865 | * mitigation is force disabled. | |
1866 | */ | |
21998a35 AS |
1867 | if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE && |
1868 | spectre_v2_user_stibp == SPECTRE_V2_USER_NONE) | |
9137bb27 | 1869 | return -EPERM; |
1978b3a5 AM |
1870 | |
1871 | if (!is_spec_ib_user_controlled()) | |
9137bb27 | 1872 | return 0; |
1978b3a5 | 1873 | |
9137bb27 TG |
1874 | task_set_spec_ib_disable(task); |
1875 | if (ctrl == PR_SPEC_FORCE_DISABLE) | |
1876 | task_set_spec_ib_force_disable(task); | |
1877 | task_update_spec_tif(task); | |
1878 | break; | |
1879 | default: | |
1880 | return -ERANGE; | |
1881 | } | |
1882 | return 0; | |
1883 | } | |
1884 | ||
8bf37d8c TG |
1885 | int arch_prctl_spec_ctrl_set(struct task_struct *task, unsigned long which, |
1886 | unsigned long ctrl) | |
1887 | { | |
1888 | switch (which) { | |
1889 | case PR_SPEC_STORE_BYPASS: | |
1890 | return ssb_prctl_set(task, ctrl); | |
9137bb27 TG |
1891 | case PR_SPEC_INDIRECT_BRANCH: |
1892 | return ib_prctl_set(task, ctrl); | |
e893bb1b BS |
1893 | case PR_SPEC_L1D_FLUSH: |
1894 | return l1d_flush_prctl_set(task, ctrl); | |
8bf37d8c TG |
1895 | default: |
1896 | return -ENODEV; | |
1897 | } | |
1898 | } | |
1899 | ||
1900 | #ifdef CONFIG_SECCOMP | |
1901 | void arch_seccomp_spec_mitigate(struct task_struct *task) | |
1902 | { | |
f21b53b2 KC |
1903 | if (ssb_mode == SPEC_STORE_BYPASS_SECCOMP) |
1904 | ssb_prctl_set(task, PR_SPEC_FORCE_DISABLE); | |
21998a35 AS |
1905 | if (spectre_v2_user_ibpb == SPECTRE_V2_USER_SECCOMP || |
1906 | spectre_v2_user_stibp == SPECTRE_V2_USER_SECCOMP) | |
6b3e64c2 | 1907 | ib_prctl_set(task, PR_SPEC_FORCE_DISABLE); |
8bf37d8c TG |
1908 | } |
1909 | #endif | |
1910 | ||
e893bb1b BS |
1911 | static int l1d_flush_prctl_get(struct task_struct *task) |
1912 | { | |
1913 | if (!static_branch_unlikely(&switch_mm_cond_l1d_flush)) | |
1914 | return PR_SPEC_FORCE_DISABLE; | |
1915 | ||
1916 | if (test_ti_thread_flag(&task->thread_info, TIF_SPEC_L1D_FLUSH)) | |
1917 | return PR_SPEC_PRCTL | PR_SPEC_ENABLE; | |
1918 | else | |
1919 | return PR_SPEC_PRCTL | PR_SPEC_DISABLE; | |
1920 | } | |
1921 | ||
7bbf1373 | 1922 | static int ssb_prctl_get(struct task_struct *task) |
a73ec77e TG |
1923 | { |
1924 | switch (ssb_mode) { | |
1925 | case SPEC_STORE_BYPASS_DISABLE: | |
1926 | return PR_SPEC_DISABLE; | |
f21b53b2 | 1927 | case SPEC_STORE_BYPASS_SECCOMP: |
a73ec77e | 1928 | case SPEC_STORE_BYPASS_PRCTL: |
356e4bff TG |
1929 | if (task_spec_ssb_force_disable(task)) |
1930 | return PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE; | |
71368af9 WL |
1931 | if (task_spec_ssb_noexec(task)) |
1932 | return PR_SPEC_PRCTL | PR_SPEC_DISABLE_NOEXEC; | |
356e4bff | 1933 | if (task_spec_ssb_disable(task)) |
a73ec77e TG |
1934 | return PR_SPEC_PRCTL | PR_SPEC_DISABLE; |
1935 | return PR_SPEC_PRCTL | PR_SPEC_ENABLE; | |
1936 | default: | |
1937 | if (boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS)) | |
1938 | return PR_SPEC_ENABLE; | |
1939 | return PR_SPEC_NOT_AFFECTED; | |
1940 | } | |
1941 | } | |
1942 | ||
9137bb27 TG |
1943 | static int ib_prctl_get(struct task_struct *task) |
1944 | { | |
1945 | if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2)) | |
1946 | return PR_SPEC_NOT_AFFECTED; | |
1947 | ||
21998a35 AS |
1948 | if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE && |
1949 | spectre_v2_user_stibp == SPECTRE_V2_USER_NONE) | |
9137bb27 | 1950 | return PR_SPEC_ENABLE; |
1978b3a5 | 1951 | else if (is_spec_ib_user_controlled()) { |
9137bb27 TG |
1952 | if (task_spec_ib_force_disable(task)) |
1953 | return PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE; | |
1954 | if (task_spec_ib_disable(task)) | |
1955 | return PR_SPEC_PRCTL | PR_SPEC_DISABLE; | |
1956 | return PR_SPEC_PRCTL | PR_SPEC_ENABLE; | |
1978b3a5 AM |
1957 | } else if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT || |
1958 | spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT || | |
1959 | spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED) | |
1960 | return PR_SPEC_DISABLE; | |
1961 | else | |
9137bb27 | 1962 | return PR_SPEC_NOT_AFFECTED; |
9137bb27 TG |
1963 | } |
1964 | ||
7bbf1373 | 1965 | int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which) |
a73ec77e TG |
1966 | { |
1967 | switch (which) { | |
1968 | case PR_SPEC_STORE_BYPASS: | |
7bbf1373 | 1969 | return ssb_prctl_get(task); |
9137bb27 TG |
1970 | case PR_SPEC_INDIRECT_BRANCH: |
1971 | return ib_prctl_get(task); | |
e893bb1b BS |
1972 | case PR_SPEC_L1D_FLUSH: |
1973 | return l1d_flush_prctl_get(task); | |
a73ec77e TG |
1974 | default: |
1975 | return -ENODEV; | |
1976 | } | |
1977 | } | |
1978 | ||
77243971 KRW |
1979 | void x86_spec_ctrl_setup_ap(void) |
1980 | { | |
7eb8956a | 1981 | if (boot_cpu_has(X86_FEATURE_MSR_SPEC_CTRL)) |
1d800213 | 1982 | write_spec_ctrl_current(x86_spec_ctrl_base, true); |
764f3c21 KRW |
1983 | |
1984 | if (ssb_mode == SPEC_STORE_BYPASS_DISABLE) | |
9f65fb29 | 1985 | x86_amd_ssb_disable(); |
77243971 KRW |
1986 | } |
1987 | ||
b8e8c830 PB |
1988 | bool itlb_multihit_kvm_mitigation; |
1989 | EXPORT_SYMBOL_GPL(itlb_multihit_kvm_mitigation); | |
1990 | ||
56563f53 KRW |
1991 | #undef pr_fmt |
1992 | #define pr_fmt(fmt) "L1TF: " fmt | |
72c6d2db | 1993 | |
d90a7a0e JK |
1994 | /* Default mitigation for L1TF-affected CPUs */ |
1995 | enum l1tf_mitigations l1tf_mitigation __ro_after_init = L1TF_MITIGATION_FLUSH; | |
72c6d2db | 1996 | #if IS_ENABLED(CONFIG_KVM_INTEL) |
d90a7a0e | 1997 | EXPORT_SYMBOL_GPL(l1tf_mitigation); |
1eb46908 | 1998 | #endif |
895ae47f | 1999 | enum vmx_l1d_flush_state l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO; |
72c6d2db | 2000 | EXPORT_SYMBOL_GPL(l1tf_vmx_mitigation); |
72c6d2db | 2001 | |
cc51e542 AK |
2002 | /* |
2003 | * These CPUs all support 44bits physical address space internally in the | |
2004 | * cache but CPUID can report a smaller number of physical address bits. | |
2005 | * | |
2006 | * The L1TF mitigation uses the top most address bit for the inversion of | |
2007 | * non present PTEs. When the installed memory reaches into the top most | |
2008 | * address bit due to memory holes, which has been observed on machines | |
2009 | * which report 36bits physical address bits and have 32G RAM installed, | |
2010 | * then the mitigation range check in l1tf_select_mitigation() triggers. | |
2011 | * This is a false positive because the mitigation is still possible due to | |
2012 | * the fact that the cache uses 44bit internally. Use the cache bits | |
2013 | * instead of the reported physical bits and adjust them on the affected | |
2014 | * machines to 44bit if the reported bits are less than 44. | |
2015 | */ | |
2016 | static void override_cache_bits(struct cpuinfo_x86 *c) | |
2017 | { | |
2018 | if (c->x86 != 6) | |
2019 | return; | |
2020 | ||
2021 | switch (c->x86_model) { | |
2022 | case INTEL_FAM6_NEHALEM: | |
2023 | case INTEL_FAM6_WESTMERE: | |
2024 | case INTEL_FAM6_SANDYBRIDGE: | |
2025 | case INTEL_FAM6_IVYBRIDGE: | |
c66f78a6 | 2026 | case INTEL_FAM6_HASWELL: |
af239c44 | 2027 | case INTEL_FAM6_HASWELL_L: |
5e741407 | 2028 | case INTEL_FAM6_HASWELL_G: |
c66f78a6 | 2029 | case INTEL_FAM6_BROADWELL: |
5e741407 | 2030 | case INTEL_FAM6_BROADWELL_G: |
af239c44 | 2031 | case INTEL_FAM6_SKYLAKE_L: |
c66f78a6 | 2032 | case INTEL_FAM6_SKYLAKE: |
af239c44 | 2033 | case INTEL_FAM6_KABYLAKE_L: |
c66f78a6 | 2034 | case INTEL_FAM6_KABYLAKE: |
cc51e542 AK |
2035 | if (c->x86_cache_bits < 44) |
2036 | c->x86_cache_bits = 44; | |
2037 | break; | |
2038 | } | |
2039 | } | |
2040 | ||
56563f53 KRW |
2041 | static void __init l1tf_select_mitigation(void) |
2042 | { | |
2043 | u64 half_pa; | |
2044 | ||
2045 | if (!boot_cpu_has_bug(X86_BUG_L1TF)) | |
2046 | return; | |
2047 | ||
d68be4c4 JP |
2048 | if (cpu_mitigations_off()) |
2049 | l1tf_mitigation = L1TF_MITIGATION_OFF; | |
2050 | else if (cpu_mitigations_auto_nosmt()) | |
2051 | l1tf_mitigation = L1TF_MITIGATION_FLUSH_NOSMT; | |
2052 | ||
cc51e542 AK |
2053 | override_cache_bits(&boot_cpu_data); |
2054 | ||
d90a7a0e JK |
2055 | switch (l1tf_mitigation) { |
2056 | case L1TF_MITIGATION_OFF: | |
2057 | case L1TF_MITIGATION_FLUSH_NOWARN: | |
2058 | case L1TF_MITIGATION_FLUSH: | |
2059 | break; | |
2060 | case L1TF_MITIGATION_FLUSH_NOSMT: | |
2061 | case L1TF_MITIGATION_FULL: | |
2062 | cpu_smt_disable(false); | |
2063 | break; | |
2064 | case L1TF_MITIGATION_FULL_FORCE: | |
2065 | cpu_smt_disable(true); | |
2066 | break; | |
2067 | } | |
2068 | ||
56563f53 KRW |
2069 | #if CONFIG_PGTABLE_LEVELS == 2 |
2070 | pr_warn("Kernel not compiled for PAE. No mitigation for L1TF\n"); | |
2071 | return; | |
2072 | #endif | |
2073 | ||
56563f53 | 2074 | half_pa = (u64)l1tf_pfn_limit() << PAGE_SHIFT; |
5b5e4d62 MH |
2075 | if (l1tf_mitigation != L1TF_MITIGATION_OFF && |
2076 | e820__mapped_any(half_pa, ULLONG_MAX - half_pa, E820_TYPE_RAM)) { | |
56563f53 | 2077 | pr_warn("System has more than MAX_PA/2 memory. L1TF mitigation not effective.\n"); |
6a012288 VB |
2078 | pr_info("You may make it effective by booting the kernel with mem=%llu parameter.\n", |
2079 | half_pa); | |
2080 | pr_info("However, doing so will make a part of your RAM unusable.\n"); | |
65fd4cb6 | 2081 | pr_info("Reading https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html might help you decide.\n"); |
56563f53 KRW |
2082 | return; |
2083 | } | |
2084 | ||
2085 | setup_force_cpu_cap(X86_FEATURE_L1TF_PTEINV); | |
2086 | } | |
d90a7a0e JK |
2087 | |
2088 | static int __init l1tf_cmdline(char *str) | |
2089 | { | |
2090 | if (!boot_cpu_has_bug(X86_BUG_L1TF)) | |
2091 | return 0; | |
2092 | ||
2093 | if (!str) | |
2094 | return -EINVAL; | |
2095 | ||
2096 | if (!strcmp(str, "off")) | |
2097 | l1tf_mitigation = L1TF_MITIGATION_OFF; | |
2098 | else if (!strcmp(str, "flush,nowarn")) | |
2099 | l1tf_mitigation = L1TF_MITIGATION_FLUSH_NOWARN; | |
2100 | else if (!strcmp(str, "flush")) | |
2101 | l1tf_mitigation = L1TF_MITIGATION_FLUSH; | |
2102 | else if (!strcmp(str, "flush,nosmt")) | |
2103 | l1tf_mitigation = L1TF_MITIGATION_FLUSH_NOSMT; | |
2104 | else if (!strcmp(str, "full")) | |
2105 | l1tf_mitigation = L1TF_MITIGATION_FULL; | |
2106 | else if (!strcmp(str, "full,force")) | |
2107 | l1tf_mitigation = L1TF_MITIGATION_FULL_FORCE; | |
2108 | ||
2109 | return 0; | |
2110 | } | |
2111 | early_param("l1tf", l1tf_cmdline); | |
2112 | ||
56563f53 | 2113 | #undef pr_fmt |
39226ef0 | 2114 | #define pr_fmt(fmt) fmt |
56563f53 | 2115 | |
61dc0f55 | 2116 | #ifdef CONFIG_SYSFS |
d1059518 | 2117 | |
72c6d2db TG |
2118 | #define L1TF_DEFAULT_MSG "Mitigation: PTE Inversion" |
2119 | ||
2120 | #if IS_ENABLED(CONFIG_KVM_INTEL) | |
8770709f | 2121 | static const char * const l1tf_vmx_states[] = { |
a7b9020b TG |
2122 | [VMENTER_L1D_FLUSH_AUTO] = "auto", |
2123 | [VMENTER_L1D_FLUSH_NEVER] = "vulnerable", | |
2124 | [VMENTER_L1D_FLUSH_COND] = "conditional cache flushes", | |
2125 | [VMENTER_L1D_FLUSH_ALWAYS] = "cache flushes", | |
2126 | [VMENTER_L1D_FLUSH_EPT_DISABLED] = "EPT disabled", | |
8e0b2b91 | 2127 | [VMENTER_L1D_FLUSH_NOT_REQUIRED] = "flush not necessary" |
72c6d2db TG |
2128 | }; |
2129 | ||
2130 | static ssize_t l1tf_show_state(char *buf) | |
2131 | { | |
2132 | if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_AUTO) | |
2133 | return sprintf(buf, "%s\n", L1TF_DEFAULT_MSG); | |
2134 | ||
ea156d19 PB |
2135 | if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_EPT_DISABLED || |
2136 | (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_NEVER && | |
130d6f94 | 2137 | sched_smt_active())) { |
ea156d19 PB |
2138 | return sprintf(buf, "%s; VMX: %s\n", L1TF_DEFAULT_MSG, |
2139 | l1tf_vmx_states[l1tf_vmx_mitigation]); | |
130d6f94 | 2140 | } |
ea156d19 PB |
2141 | |
2142 | return sprintf(buf, "%s; VMX: %s, SMT %s\n", L1TF_DEFAULT_MSG, | |
2143 | l1tf_vmx_states[l1tf_vmx_mitigation], | |
130d6f94 | 2144 | sched_smt_active() ? "vulnerable" : "disabled"); |
72c6d2db | 2145 | } |
b8e8c830 PB |
2146 | |
2147 | static ssize_t itlb_multihit_show_state(char *buf) | |
2148 | { | |
f29dfa53 PG |
2149 | if (!boot_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) || |
2150 | !boot_cpu_has(X86_FEATURE_VMX)) | |
2151 | return sprintf(buf, "KVM: Mitigation: VMX unsupported\n"); | |
2152 | else if (!(cr4_read_shadow() & X86_CR4_VMXE)) | |
2153 | return sprintf(buf, "KVM: Mitigation: VMX disabled\n"); | |
2154 | else if (itlb_multihit_kvm_mitigation) | |
b8e8c830 PB |
2155 | return sprintf(buf, "KVM: Mitigation: Split huge pages\n"); |
2156 | else | |
2157 | return sprintf(buf, "KVM: Vulnerable\n"); | |
2158 | } | |
72c6d2db TG |
2159 | #else |
2160 | static ssize_t l1tf_show_state(char *buf) | |
2161 | { | |
2162 | return sprintf(buf, "%s\n", L1TF_DEFAULT_MSG); | |
2163 | } | |
72c6d2db | 2164 | |
db4d30fb VT |
2165 | static ssize_t itlb_multihit_show_state(char *buf) |
2166 | { | |
2167 | return sprintf(buf, "Processor vulnerable\n"); | |
2168 | } | |
b8e8c830 | 2169 | #endif |
db4d30fb | 2170 | |
8a4b06d3 TG |
2171 | static ssize_t mds_show_state(char *buf) |
2172 | { | |
517c3ba0 | 2173 | if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) { |
8a4b06d3 TG |
2174 | return sprintf(buf, "%s; SMT Host state unknown\n", |
2175 | mds_strings[mds_mitigation]); | |
2176 | } | |
2177 | ||
2178 | if (boot_cpu_has(X86_BUG_MSBDS_ONLY)) { | |
2179 | return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation], | |
e2c3c947 KRW |
2180 | (mds_mitigation == MDS_MITIGATION_OFF ? "vulnerable" : |
2181 | sched_smt_active() ? "mitigated" : "disabled")); | |
8a4b06d3 TG |
2182 | } |
2183 | ||
2184 | return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation], | |
2185 | sched_smt_active() ? "vulnerable" : "disabled"); | |
2186 | } | |
2187 | ||
6608b45a PG |
2188 | static ssize_t tsx_async_abort_show_state(char *buf) |
2189 | { | |
2190 | if ((taa_mitigation == TAA_MITIGATION_TSX_DISABLED) || | |
2191 | (taa_mitigation == TAA_MITIGATION_OFF)) | |
2192 | return sprintf(buf, "%s\n", taa_strings[taa_mitigation]); | |
2193 | ||
2194 | if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) { | |
2195 | return sprintf(buf, "%s; SMT Host state unknown\n", | |
2196 | taa_strings[taa_mitigation]); | |
2197 | } | |
2198 | ||
2199 | return sprintf(buf, "%s; SMT %s\n", taa_strings[taa_mitigation], | |
2200 | sched_smt_active() ? "vulnerable" : "disabled"); | |
2201 | } | |
2202 | ||
01489569 PG |
2203 | static ssize_t mmio_stale_data_show_state(char *buf) |
2204 | { | |
2205 | if (mmio_mitigation == MMIO_MITIGATION_OFF) | |
2206 | return sysfs_emit(buf, "%s\n", mmio_strings[mmio_mitigation]); | |
2207 | ||
2208 | if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) { | |
2209 | return sysfs_emit(buf, "%s; SMT Host state unknown\n", | |
2210 | mmio_strings[mmio_mitigation]); | |
2211 | } | |
2212 | ||
2213 | return sysfs_emit(buf, "%s; SMT %s\n", mmio_strings[mmio_mitigation], | |
2214 | sched_smt_active() ? "vulnerable" : "disabled"); | |
2215 | } | |
2216 | ||
a8f76ae4 TC |
2217 | static char *stibp_state(void) |
2218 | { | |
ddf9f0cd | 2219 | if (spectre_v2_in_ibrs_mode(spectre_v2_enabled)) |
34bce7c9 TC |
2220 | return ""; |
2221 | ||
21998a35 | 2222 | switch (spectre_v2_user_stibp) { |
fa1202ef TG |
2223 | case SPECTRE_V2_USER_NONE: |
2224 | return ", STIBP: disabled"; | |
2225 | case SPECTRE_V2_USER_STRICT: | |
2226 | return ", STIBP: forced"; | |
20c3a2c3 TL |
2227 | case SPECTRE_V2_USER_STRICT_PREFERRED: |
2228 | return ", STIBP: always-on"; | |
9137bb27 | 2229 | case SPECTRE_V2_USER_PRCTL: |
6b3e64c2 | 2230 | case SPECTRE_V2_USER_SECCOMP: |
7cc765a6 TG |
2231 | if (static_key_enabled(&switch_to_cond_stibp)) |
2232 | return ", STIBP: conditional"; | |
fa1202ef TG |
2233 | } |
2234 | return ""; | |
a8f76ae4 TC |
2235 | } |
2236 | ||
2237 | static char *ibpb_state(void) | |
2238 | { | |
4c71a2b6 | 2239 | if (boot_cpu_has(X86_FEATURE_IBPB)) { |
7cc765a6 | 2240 | if (static_key_enabled(&switch_mm_always_ibpb)) |
4c71a2b6 | 2241 | return ", IBPB: always-on"; |
7cc765a6 TG |
2242 | if (static_key_enabled(&switch_mm_cond_ibpb)) |
2243 | return ", IBPB: conditional"; | |
2244 | return ", IBPB: disabled"; | |
4c71a2b6 TG |
2245 | } |
2246 | return ""; | |
a8f76ae4 TC |
2247 | } |
2248 | ||
534fcc9a JP |
2249 | static ssize_t spectre_v2_show_state(char *buf) |
2250 | { | |
92cf97b2 JP |
2251 | if (spectre_v2_enabled == SPECTRE_V2_LFENCE) |
2252 | return sprintf(buf, "Vulnerable: LFENCE\n"); | |
2253 | ||
534fcc9a | 2254 | if (spectre_v2_enabled == SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled()) |
810643a7 JP |
2255 | return sprintf(buf, "Vulnerable: eIBRS with unprivileged eBPF\n"); |
2256 | ||
2257 | if (sched_smt_active() && unprivileged_ebpf_enabled() && | |
2258 | spectre_v2_enabled == SPECTRE_V2_EIBRS_LFENCE) | |
2259 | return sprintf(buf, "Vulnerable: eIBRS+LFENCE with unprivileged eBPF and SMT\n"); | |
534fcc9a JP |
2260 | |
2261 | return sprintf(buf, "%s%s%s%s%s%s\n", | |
2262 | spectre_v2_strings[spectre_v2_enabled], | |
2263 | ibpb_state(), | |
2264 | boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "", | |
2265 | stibp_state(), | |
2266 | boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "", | |
2267 | spectre_v2_module_string()); | |
2268 | } | |
2269 | ||
7e5b3c26 MG |
2270 | static ssize_t srbds_show_state(char *buf) |
2271 | { | |
2272 | return sprintf(buf, "%s\n", srbds_strings[srbds_mitigation]); | |
2273 | } | |
2274 | ||
c9a77c32 AC |
2275 | static ssize_t retbleed_show_state(char *buf) |
2276 | { | |
d8bc226a KP |
2277 | if (retbleed_mitigation == RETBLEED_MITIGATION_UNRET) { |
2278 | if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD && | |
2279 | boot_cpu_data.x86_vendor != X86_VENDOR_HYGON) | |
2280 | return sprintf(buf, "Vulnerable: untrained return thunk on non-Zen uarch\n"); | |
2281 | ||
2282 | return sprintf(buf, "%s; SMT %s\n", | |
2283 | retbleed_strings[retbleed_mitigation], | |
2284 | !sched_smt_active() ? "disabled" : | |
2285 | spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT || | |
2286 | spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED ? | |
2287 | "enabled with STIBP protection" : "vulnerable"); | |
2288 | } | |
8ed18e15 AC |
2289 | |
2290 | return sprintf(buf, "%s\n", retbleed_strings[retbleed_mitigation]); | |
c9a77c32 AC |
2291 | } |
2292 | ||
7bb4d366 | 2293 | static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr, |
ffed645e | 2294 | char *buf, unsigned int bug) |
61dc0f55 | 2295 | { |
d1059518 | 2296 | if (!boot_cpu_has_bug(bug)) |
61dc0f55 | 2297 | return sprintf(buf, "Not affected\n"); |
d1059518 KRW |
2298 | |
2299 | switch (bug) { | |
2300 | case X86_BUG_CPU_MELTDOWN: | |
2301 | if (boot_cpu_has(X86_FEATURE_PTI)) | |
2302 | return sprintf(buf, "Mitigation: PTI\n"); | |
2303 | ||
6cb2b08f JK |
2304 | if (hypervisor_is_type(X86_HYPER_XEN_PV)) |
2305 | return sprintf(buf, "Unknown (XEN PV detected, hypervisor mitigation required)\n"); | |
2306 | ||
d1059518 KRW |
2307 | break; |
2308 | ||
2309 | case X86_BUG_SPECTRE_V1: | |
a2059825 | 2310 | return sprintf(buf, "%s\n", spectre_v1_strings[spectre_v1_mitigation]); |
d1059518 KRW |
2311 | |
2312 | case X86_BUG_SPECTRE_V2: | |
534fcc9a | 2313 | return spectre_v2_show_state(buf); |
d1059518 | 2314 | |
24f7fc83 KRW |
2315 | case X86_BUG_SPEC_STORE_BYPASS: |
2316 | return sprintf(buf, "%s\n", ssb_strings[ssb_mode]); | |
2317 | ||
17dbca11 AK |
2318 | case X86_BUG_L1TF: |
2319 | if (boot_cpu_has(X86_FEATURE_L1TF_PTEINV)) | |
72c6d2db | 2320 | return l1tf_show_state(buf); |
17dbca11 | 2321 | break; |
8a4b06d3 TG |
2322 | |
2323 | case X86_BUG_MDS: | |
2324 | return mds_show_state(buf); | |
2325 | ||
6608b45a PG |
2326 | case X86_BUG_TAA: |
2327 | return tsx_async_abort_show_state(buf); | |
2328 | ||
db4d30fb VT |
2329 | case X86_BUG_ITLB_MULTIHIT: |
2330 | return itlb_multihit_show_state(buf); | |
2331 | ||
7e5b3c26 MG |
2332 | case X86_BUG_SRBDS: |
2333 | return srbds_show_state(buf); | |
2334 | ||
01489569 PG |
2335 | case X86_BUG_MMIO_STALE_DATA: |
2336 | return mmio_stale_data_show_state(buf); | |
2337 | ||
c9a77c32 AC |
2338 | case X86_BUG_RETBLEED: |
2339 | return retbleed_show_state(buf); | |
2340 | ||
d1059518 KRW |
2341 | default: |
2342 | break; | |
2343 | } | |
2344 | ||
61dc0f55 TG |
2345 | return sprintf(buf, "Vulnerable\n"); |
2346 | } | |
2347 | ||
d1059518 KRW |
2348 | ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) |
2349 | { | |
2350 | return cpu_show_common(dev, attr, buf, X86_BUG_CPU_MELTDOWN); | |
2351 | } | |
2352 | ||
21e433bd | 2353 | ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf) |
61dc0f55 | 2354 | { |
d1059518 | 2355 | return cpu_show_common(dev, attr, buf, X86_BUG_SPECTRE_V1); |
61dc0f55 TG |
2356 | } |
2357 | ||
21e433bd | 2358 | ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf) |
61dc0f55 | 2359 | { |
d1059518 | 2360 | return cpu_show_common(dev, attr, buf, X86_BUG_SPECTRE_V2); |
61dc0f55 | 2361 | } |
c456442c KRW |
2362 | |
2363 | ssize_t cpu_show_spec_store_bypass(struct device *dev, struct device_attribute *attr, char *buf) | |
2364 | { | |
2365 | return cpu_show_common(dev, attr, buf, X86_BUG_SPEC_STORE_BYPASS); | |
2366 | } | |
17dbca11 AK |
2367 | |
2368 | ssize_t cpu_show_l1tf(struct device *dev, struct device_attribute *attr, char *buf) | |
2369 | { | |
2370 | return cpu_show_common(dev, attr, buf, X86_BUG_L1TF); | |
2371 | } | |
8a4b06d3 TG |
2372 | |
2373 | ssize_t cpu_show_mds(struct device *dev, struct device_attribute *attr, char *buf) | |
2374 | { | |
2375 | return cpu_show_common(dev, attr, buf, X86_BUG_MDS); | |
2376 | } | |
6608b45a PG |
2377 | |
2378 | ssize_t cpu_show_tsx_async_abort(struct device *dev, struct device_attribute *attr, char *buf) | |
2379 | { | |
2380 | return cpu_show_common(dev, attr, buf, X86_BUG_TAA); | |
2381 | } | |
db4d30fb VT |
2382 | |
2383 | ssize_t cpu_show_itlb_multihit(struct device *dev, struct device_attribute *attr, char *buf) | |
2384 | { | |
2385 | return cpu_show_common(dev, attr, buf, X86_BUG_ITLB_MULTIHIT); | |
2386 | } | |
7e5b3c26 MG |
2387 | |
2388 | ssize_t cpu_show_srbds(struct device *dev, struct device_attribute *attr, char *buf) | |
2389 | { | |
2390 | return cpu_show_common(dev, attr, buf, X86_BUG_SRBDS); | |
2391 | } | |
01489569 PG |
2392 | |
2393 | ssize_t cpu_show_mmio_stale_data(struct device *dev, struct device_attribute *attr, char *buf) | |
2394 | { | |
2395 | return cpu_show_common(dev, attr, buf, X86_BUG_MMIO_STALE_DATA); | |
2396 | } | |
c9a77c32 AC |
2397 | |
2398 | ssize_t cpu_show_retbleed(struct device *dev, struct device_attribute *attr, char *buf) | |
2399 | { | |
2400 | return cpu_show_common(dev, attr, buf, X86_BUG_RETBLEED); | |
2401 | } | |
61dc0f55 | 2402 | #endif |