xref: /openbmc/linux/arch/x86/kernel/cpu/intel.c (revision 74be2d3b)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/pgtable.h>
4 
5 #include <linux/string.h>
6 #include <linux/bitops.h>
7 #include <linux/smp.h>
8 #include <linux/sched.h>
9 #include <linux/sched/clock.h>
10 #include <linux/thread_info.h>
11 #include <linux/init.h>
12 #include <linux/uaccess.h>
13 
14 #include <asm/cpufeature.h>
15 #include <asm/msr.h>
16 #include <asm/bugs.h>
17 #include <asm/cpu.h>
18 #include <asm/intel-family.h>
19 #include <asm/microcode_intel.h>
20 #include <asm/hwcap2.h>
21 #include <asm/elf.h>
22 #include <asm/cpu_device_id.h>
23 #include <asm/cmdline.h>
24 #include <asm/traps.h>
25 #include <asm/resctrl.h>
26 
27 #ifdef CONFIG_X86_64
28 #include <linux/topology.h>
29 #endif
30 
31 #include "cpu.h"
32 
33 #ifdef CONFIG_X86_LOCAL_APIC
34 #include <asm/mpspec.h>
35 #include <asm/apic.h>
36 #endif
37 
38 enum split_lock_detect_state {
39 	sld_off = 0,
40 	sld_warn,
41 	sld_fatal,
42 };
43 
44 /*
45  * Default to sld_off because most systems do not support split lock detection
46  * split_lock_setup() will switch this to sld_warn on systems that support
47  * split lock detect, unless there is a command line override.
48  */
49 static enum split_lock_detect_state sld_state __ro_after_init = sld_off;
50 static u64 msr_test_ctrl_cache __ro_after_init;
51 
52 /*
53  * Processors which have self-snooping capability can handle conflicting
54  * memory type across CPUs by snooping its own cache. However, there exists
55  * CPU models in which having conflicting memory types still leads to
56  * unpredictable behavior, machine check errors, or hangs. Clear this
57  * feature to prevent its use on machines with known erratas.
58  */
59 static void check_memory_type_self_snoop_errata(struct cpuinfo_x86 *c)
60 {
61 	switch (c->x86_model) {
62 	case INTEL_FAM6_CORE_YONAH:
63 	case INTEL_FAM6_CORE2_MEROM:
64 	case INTEL_FAM6_CORE2_MEROM_L:
65 	case INTEL_FAM6_CORE2_PENRYN:
66 	case INTEL_FAM6_CORE2_DUNNINGTON:
67 	case INTEL_FAM6_NEHALEM:
68 	case INTEL_FAM6_NEHALEM_G:
69 	case INTEL_FAM6_NEHALEM_EP:
70 	case INTEL_FAM6_NEHALEM_EX:
71 	case INTEL_FAM6_WESTMERE:
72 	case INTEL_FAM6_WESTMERE_EP:
73 	case INTEL_FAM6_SANDYBRIDGE:
74 		setup_clear_cpu_cap(X86_FEATURE_SELFSNOOP);
75 	}
76 }
77 
78 static bool ring3mwait_disabled __read_mostly;
79 
80 static int __init ring3mwait_disable(char *__unused)
81 {
82 	ring3mwait_disabled = true;
83 	return 0;
84 }
85 __setup("ring3mwait=disable", ring3mwait_disable);
86 
87 static void probe_xeon_phi_r3mwait(struct cpuinfo_x86 *c)
88 {
89 	/*
90 	 * Ring 3 MONITOR/MWAIT feature cannot be detected without
91 	 * cpu model and family comparison.
92 	 */
93 	if (c->x86 != 6)
94 		return;
95 	switch (c->x86_model) {
96 	case INTEL_FAM6_XEON_PHI_KNL:
97 	case INTEL_FAM6_XEON_PHI_KNM:
98 		break;
99 	default:
100 		return;
101 	}
102 
103 	if (ring3mwait_disabled)
104 		return;
105 
106 	set_cpu_cap(c, X86_FEATURE_RING3MWAIT);
107 	this_cpu_or(msr_misc_features_shadow,
108 		    1UL << MSR_MISC_FEATURES_ENABLES_RING3MWAIT_BIT);
109 
110 	if (c == &boot_cpu_data)
111 		ELF_HWCAP2 |= HWCAP2_RING3MWAIT;
112 }
113 
114 /*
115  * Early microcode releases for the Spectre v2 mitigation were broken.
116  * Information taken from;
117  * - https://newsroom.intel.com/wp-content/uploads/sites/11/2018/03/microcode-update-guidance.pdf
118  * - https://kb.vmware.com/s/article/52345
119  * - Microcode revisions observed in the wild
120  * - Release note from 20180108 microcode release
121  */
122 struct sku_microcode {
123 	u8 model;
124 	u8 stepping;
125 	u32 microcode;
126 };
127 static const struct sku_microcode spectre_bad_microcodes[] = {
128 	{ INTEL_FAM6_KABYLAKE,		0x0B,	0x80 },
129 	{ INTEL_FAM6_KABYLAKE,		0x0A,	0x80 },
130 	{ INTEL_FAM6_KABYLAKE,		0x09,	0x80 },
131 	{ INTEL_FAM6_KABYLAKE_L,	0x0A,	0x80 },
132 	{ INTEL_FAM6_KABYLAKE_L,	0x09,	0x80 },
133 	{ INTEL_FAM6_SKYLAKE_X,		0x03,	0x0100013e },
134 	{ INTEL_FAM6_SKYLAKE_X,		0x04,	0x0200003c },
135 	{ INTEL_FAM6_BROADWELL,		0x04,	0x28 },
136 	{ INTEL_FAM6_BROADWELL_G,	0x01,	0x1b },
137 	{ INTEL_FAM6_BROADWELL_D,	0x02,	0x14 },
138 	{ INTEL_FAM6_BROADWELL_D,	0x03,	0x07000011 },
139 	{ INTEL_FAM6_BROADWELL_X,	0x01,	0x0b000025 },
140 	{ INTEL_FAM6_HASWELL_L,		0x01,	0x21 },
141 	{ INTEL_FAM6_HASWELL_G,		0x01,	0x18 },
142 	{ INTEL_FAM6_HASWELL,		0x03,	0x23 },
143 	{ INTEL_FAM6_HASWELL_X,		0x02,	0x3b },
144 	{ INTEL_FAM6_HASWELL_X,		0x04,	0x10 },
145 	{ INTEL_FAM6_IVYBRIDGE_X,	0x04,	0x42a },
146 	/* Observed in the wild */
147 	{ INTEL_FAM6_SANDYBRIDGE_X,	0x06,	0x61b },
148 	{ INTEL_FAM6_SANDYBRIDGE_X,	0x07,	0x712 },
149 };
150 
151 static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
152 {
153 	int i;
154 
155 	/*
156 	 * We know that the hypervisor lie to us on the microcode version so
157 	 * we may as well hope that it is running the correct version.
158 	 */
159 	if (cpu_has(c, X86_FEATURE_HYPERVISOR))
160 		return false;
161 
162 	if (c->x86 != 6)
163 		return false;
164 
165 	for (i = 0; i < ARRAY_SIZE(spectre_bad_microcodes); i++) {
166 		if (c->x86_model == spectre_bad_microcodes[i].model &&
167 		    c->x86_stepping == spectre_bad_microcodes[i].stepping)
168 			return (c->microcode <= spectre_bad_microcodes[i].microcode);
169 	}
170 	return false;
171 }
172 
173 static void early_init_intel(struct cpuinfo_x86 *c)
174 {
175 	u64 misc_enable;
176 
177 	/* Unmask CPUID levels if masked: */
178 	if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) {
179 		if (msr_clear_bit(MSR_IA32_MISC_ENABLE,
180 				  MSR_IA32_MISC_ENABLE_LIMIT_CPUID_BIT) > 0) {
181 			c->cpuid_level = cpuid_eax(0);
182 			get_cpu_cap(c);
183 		}
184 	}
185 
186 	if ((c->x86 == 0xf && c->x86_model >= 0x03) ||
187 		(c->x86 == 0x6 && c->x86_model >= 0x0e))
188 		set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
189 
190 	if (c->x86 >= 6 && !cpu_has(c, X86_FEATURE_IA64))
191 		c->microcode = intel_get_microcode_revision();
192 
193 	/* Now if any of them are set, check the blacklist and clear the lot */
194 	if ((cpu_has(c, X86_FEATURE_SPEC_CTRL) ||
195 	     cpu_has(c, X86_FEATURE_INTEL_STIBP) ||
196 	     cpu_has(c, X86_FEATURE_IBRS) || cpu_has(c, X86_FEATURE_IBPB) ||
197 	     cpu_has(c, X86_FEATURE_STIBP)) && bad_spectre_microcode(c)) {
198 		pr_warn("Intel Spectre v2 broken microcode detected; disabling Speculation Control\n");
199 		setup_clear_cpu_cap(X86_FEATURE_IBRS);
200 		setup_clear_cpu_cap(X86_FEATURE_IBPB);
201 		setup_clear_cpu_cap(X86_FEATURE_STIBP);
202 		setup_clear_cpu_cap(X86_FEATURE_SPEC_CTRL);
203 		setup_clear_cpu_cap(X86_FEATURE_MSR_SPEC_CTRL);
204 		setup_clear_cpu_cap(X86_FEATURE_INTEL_STIBP);
205 		setup_clear_cpu_cap(X86_FEATURE_SSBD);
206 		setup_clear_cpu_cap(X86_FEATURE_SPEC_CTRL_SSBD);
207 	}
208 
209 	/*
210 	 * Atom erratum AAE44/AAF40/AAG38/AAH41:
211 	 *
212 	 * A race condition between speculative fetches and invalidating
213 	 * a large page.  This is worked around in microcode, but we
214 	 * need the microcode to have already been loaded... so if it is
215 	 * not, recommend a BIOS update and disable large pages.
216 	 */
217 	if (c->x86 == 6 && c->x86_model == 0x1c && c->x86_stepping <= 2 &&
218 	    c->microcode < 0x20e) {
219 		pr_warn("Atom PSE erratum detected, BIOS microcode update recommended\n");
220 		clear_cpu_cap(c, X86_FEATURE_PSE);
221 	}
222 
223 #ifdef CONFIG_X86_64
224 	set_cpu_cap(c, X86_FEATURE_SYSENTER32);
225 #else
226 	/* Netburst reports 64 bytes clflush size, but does IO in 128 bytes */
227 	if (c->x86 == 15 && c->x86_cache_alignment == 64)
228 		c->x86_cache_alignment = 128;
229 #endif
230 
231 	/* CPUID workaround for 0F33/0F34 CPU */
232 	if (c->x86 == 0xF && c->x86_model == 0x3
233 	    && (c->x86_stepping == 0x3 || c->x86_stepping == 0x4))
234 		c->x86_phys_bits = 36;
235 
236 	/*
237 	 * c->x86_power is 8000_0007 edx. Bit 8 is TSC runs at constant rate
238 	 * with P/T states and does not stop in deep C-states.
239 	 *
240 	 * It is also reliable across cores and sockets. (but not across
241 	 * cabinets - we turn it off in that case explicitly.)
242 	 */
243 	if (c->x86_power & (1 << 8)) {
244 		set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
245 		set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC);
246 	}
247 
248 	/* Penwell and Cloverview have the TSC which doesn't sleep on S3 */
249 	if (c->x86 == 6) {
250 		switch (c->x86_model) {
251 		case INTEL_FAM6_ATOM_SALTWELL_MID:
252 		case INTEL_FAM6_ATOM_SALTWELL_TABLET:
253 		case INTEL_FAM6_ATOM_SILVERMONT_MID:
254 		case INTEL_FAM6_ATOM_AIRMONT_NP:
255 			set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC_S3);
256 			break;
257 		default:
258 			break;
259 		}
260 	}
261 
262 	/*
263 	 * There is a known erratum on Pentium III and Core Solo
264 	 * and Core Duo CPUs.
265 	 * " Page with PAT set to WC while associated MTRR is UC
266 	 *   may consolidate to UC "
267 	 * Because of this erratum, it is better to stick with
268 	 * setting WC in MTRR rather than using PAT on these CPUs.
269 	 *
270 	 * Enable PAT WC only on P4, Core 2 or later CPUs.
271 	 */
272 	if (c->x86 == 6 && c->x86_model < 15)
273 		clear_cpu_cap(c, X86_FEATURE_PAT);
274 
275 	/*
276 	 * If fast string is not enabled in IA32_MISC_ENABLE for any reason,
277 	 * clear the fast string and enhanced fast string CPU capabilities.
278 	 */
279 	if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) {
280 		rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
281 		if (!(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) {
282 			pr_info("Disabled fast string operations\n");
283 			setup_clear_cpu_cap(X86_FEATURE_REP_GOOD);
284 			setup_clear_cpu_cap(X86_FEATURE_ERMS);
285 		}
286 	}
287 
288 	/*
289 	 * Intel Quark Core DevMan_001.pdf section 6.4.11
290 	 * "The operating system also is required to invalidate (i.e., flush)
291 	 *  the TLB when any changes are made to any of the page table entries.
292 	 *  The operating system must reload CR3 to cause the TLB to be flushed"
293 	 *
294 	 * As a result, boot_cpu_has(X86_FEATURE_PGE) in arch/x86/include/asm/tlbflush.h
295 	 * should be false so that __flush_tlb_all() causes CR3 insted of CR4.PGE
296 	 * to be modified.
297 	 */
298 	if (c->x86 == 5 && c->x86_model == 9) {
299 		pr_info("Disabling PGE capability bit\n");
300 		setup_clear_cpu_cap(X86_FEATURE_PGE);
301 	}
302 
303 	if (c->cpuid_level >= 0x00000001) {
304 		u32 eax, ebx, ecx, edx;
305 
306 		cpuid(0x00000001, &eax, &ebx, &ecx, &edx);
307 		/*
308 		 * If HTT (EDX[28]) is set EBX[16:23] contain the number of
309 		 * apicids which are reserved per package. Store the resulting
310 		 * shift value for the package management code.
311 		 */
312 		if (edx & (1U << 28))
313 			c->x86_coreid_bits = get_count_order((ebx >> 16) & 0xff);
314 	}
315 
316 	check_memory_type_self_snoop_errata(c);
317 
318 	/*
319 	 * Get the number of SMT siblings early from the extended topology
320 	 * leaf, if available. Otherwise try the legacy SMT detection.
321 	 */
322 	if (detect_extended_topology_early(c) < 0)
323 		detect_ht_early(c);
324 }
325 
326 static void bsp_init_intel(struct cpuinfo_x86 *c)
327 {
328 	resctrl_cpu_detect(c);
329 }
330 
331 #ifdef CONFIG_X86_32
332 /*
333  *	Early probe support logic for ppro memory erratum #50
334  *
335  *	This is called before we do cpu ident work
336  */
337 
338 int ppro_with_ram_bug(void)
339 {
340 	/* Uses data from early_cpu_detect now */
341 	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
342 	    boot_cpu_data.x86 == 6 &&
343 	    boot_cpu_data.x86_model == 1 &&
344 	    boot_cpu_data.x86_stepping < 8) {
345 		pr_info("Pentium Pro with Errata#50 detected. Taking evasive action.\n");
346 		return 1;
347 	}
348 	return 0;
349 }
350 
351 static void intel_smp_check(struct cpuinfo_x86 *c)
352 {
353 	/* calling is from identify_secondary_cpu() ? */
354 	if (!c->cpu_index)
355 		return;
356 
357 	/*
358 	 * Mask B, Pentium, but not Pentium MMX
359 	 */
360 	if (c->x86 == 5 &&
361 	    c->x86_stepping >= 1 && c->x86_stepping <= 4 &&
362 	    c->x86_model <= 3) {
363 		/*
364 		 * Remember we have B step Pentia with bugs
365 		 */
366 		WARN_ONCE(1, "WARNING: SMP operation may be unreliable"
367 				    "with B stepping processors.\n");
368 	}
369 }
370 
371 static int forcepae;
372 static int __init forcepae_setup(char *__unused)
373 {
374 	forcepae = 1;
375 	return 1;
376 }
377 __setup("forcepae", forcepae_setup);
378 
379 static void intel_workarounds(struct cpuinfo_x86 *c)
380 {
381 #ifdef CONFIG_X86_F00F_BUG
382 	/*
383 	 * All models of Pentium and Pentium with MMX technology CPUs
384 	 * have the F0 0F bug, which lets nonprivileged users lock up the
385 	 * system. Announce that the fault handler will be checking for it.
386 	 * The Quark is also family 5, but does not have the same bug.
387 	 */
388 	clear_cpu_bug(c, X86_BUG_F00F);
389 	if (c->x86 == 5 && c->x86_model < 9) {
390 		static int f00f_workaround_enabled;
391 
392 		set_cpu_bug(c, X86_BUG_F00F);
393 		if (!f00f_workaround_enabled) {
394 			pr_notice("Intel Pentium with F0 0F bug - workaround enabled.\n");
395 			f00f_workaround_enabled = 1;
396 		}
397 	}
398 #endif
399 
400 	/*
401 	 * SEP CPUID bug: Pentium Pro reports SEP but doesn't have it until
402 	 * model 3 mask 3
403 	 */
404 	if ((c->x86<<8 | c->x86_model<<4 | c->x86_stepping) < 0x633)
405 		clear_cpu_cap(c, X86_FEATURE_SEP);
406 
407 	/*
408 	 * PAE CPUID issue: many Pentium M report no PAE but may have a
409 	 * functionally usable PAE implementation.
410 	 * Forcefully enable PAE if kernel parameter "forcepae" is present.
411 	 */
412 	if (forcepae) {
413 		pr_warn("PAE forced!\n");
414 		set_cpu_cap(c, X86_FEATURE_PAE);
415 		add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_NOW_UNRELIABLE);
416 	}
417 
418 	/*
419 	 * P4 Xeon erratum 037 workaround.
420 	 * Hardware prefetcher may cause stale data to be loaded into the cache.
421 	 */
422 	if ((c->x86 == 15) && (c->x86_model == 1) && (c->x86_stepping == 1)) {
423 		if (msr_set_bit(MSR_IA32_MISC_ENABLE,
424 				MSR_IA32_MISC_ENABLE_PREFETCH_DISABLE_BIT) > 0) {
425 			pr_info("CPU: C0 stepping P4 Xeon detected.\n");
426 			pr_info("CPU: Disabling hardware prefetching (Erratum 037)\n");
427 		}
428 	}
429 
430 	/*
431 	 * See if we have a good local APIC by checking for buggy Pentia,
432 	 * i.e. all B steppings and the C2 stepping of P54C when using their
433 	 * integrated APIC (see 11AP erratum in "Pentium Processor
434 	 * Specification Update").
435 	 */
436 	if (boot_cpu_has(X86_FEATURE_APIC) && (c->x86<<8 | c->x86_model<<4) == 0x520 &&
437 	    (c->x86_stepping < 0x6 || c->x86_stepping == 0xb))
438 		set_cpu_bug(c, X86_BUG_11AP);
439 
440 
441 #ifdef CONFIG_X86_INTEL_USERCOPY
442 	/*
443 	 * Set up the preferred alignment for movsl bulk memory moves
444 	 */
445 	switch (c->x86) {
446 	case 4:		/* 486: untested */
447 		break;
448 	case 5:		/* Old Pentia: untested */
449 		break;
450 	case 6:		/* PII/PIII only like movsl with 8-byte alignment */
451 		movsl_mask.mask = 7;
452 		break;
453 	case 15:	/* P4 is OK down to 8-byte alignment */
454 		movsl_mask.mask = 7;
455 		break;
456 	}
457 #endif
458 
459 	intel_smp_check(c);
460 }
461 #else
462 static void intel_workarounds(struct cpuinfo_x86 *c)
463 {
464 }
465 #endif
466 
467 static void srat_detect_node(struct cpuinfo_x86 *c)
468 {
469 #ifdef CONFIG_NUMA
470 	unsigned node;
471 	int cpu = smp_processor_id();
472 
473 	/* Don't do the funky fallback heuristics the AMD version employs
474 	   for now. */
475 	node = numa_cpu_node(cpu);
476 	if (node == NUMA_NO_NODE || !node_online(node)) {
477 		/* reuse the value from init_cpu_to_node() */
478 		node = cpu_to_node(cpu);
479 	}
480 	numa_set_node(cpu, node);
481 #endif
482 }
483 
484 #define MSR_IA32_TME_ACTIVATE		0x982
485 
486 /* Helpers to access TME_ACTIVATE MSR */
487 #define TME_ACTIVATE_LOCKED(x)		(x & 0x1)
488 #define TME_ACTIVATE_ENABLED(x)		(x & 0x2)
489 
490 #define TME_ACTIVATE_POLICY(x)		((x >> 4) & 0xf)	/* Bits 7:4 */
491 #define TME_ACTIVATE_POLICY_AES_XTS_128	0
492 
493 #define TME_ACTIVATE_KEYID_BITS(x)	((x >> 32) & 0xf)	/* Bits 35:32 */
494 
495 #define TME_ACTIVATE_CRYPTO_ALGS(x)	((x >> 48) & 0xffff)	/* Bits 63:48 */
496 #define TME_ACTIVATE_CRYPTO_AES_XTS_128	1
497 
498 /* Values for mktme_status (SW only construct) */
499 #define MKTME_ENABLED			0
500 #define MKTME_DISABLED			1
501 #define MKTME_UNINITIALIZED		2
502 static int mktme_status = MKTME_UNINITIALIZED;
503 
504 static void detect_tme(struct cpuinfo_x86 *c)
505 {
506 	u64 tme_activate, tme_policy, tme_crypto_algs;
507 	int keyid_bits = 0, nr_keyids = 0;
508 	static u64 tme_activate_cpu0 = 0;
509 
510 	rdmsrl(MSR_IA32_TME_ACTIVATE, tme_activate);
511 
512 	if (mktme_status != MKTME_UNINITIALIZED) {
513 		if (tme_activate != tme_activate_cpu0) {
514 			/* Broken BIOS? */
515 			pr_err_once("x86/tme: configuration is inconsistent between CPUs\n");
516 			pr_err_once("x86/tme: MKTME is not usable\n");
517 			mktme_status = MKTME_DISABLED;
518 
519 			/* Proceed. We may need to exclude bits from x86_phys_bits. */
520 		}
521 	} else {
522 		tme_activate_cpu0 = tme_activate;
523 	}
524 
525 	if (!TME_ACTIVATE_LOCKED(tme_activate) || !TME_ACTIVATE_ENABLED(tme_activate)) {
526 		pr_info_once("x86/tme: not enabled by BIOS\n");
527 		mktme_status = MKTME_DISABLED;
528 		return;
529 	}
530 
531 	if (mktme_status != MKTME_UNINITIALIZED)
532 		goto detect_keyid_bits;
533 
534 	pr_info("x86/tme: enabled by BIOS\n");
535 
536 	tme_policy = TME_ACTIVATE_POLICY(tme_activate);
537 	if (tme_policy != TME_ACTIVATE_POLICY_AES_XTS_128)
538 		pr_warn("x86/tme: Unknown policy is active: %#llx\n", tme_policy);
539 
540 	tme_crypto_algs = TME_ACTIVATE_CRYPTO_ALGS(tme_activate);
541 	if (!(tme_crypto_algs & TME_ACTIVATE_CRYPTO_AES_XTS_128)) {
542 		pr_err("x86/mktme: No known encryption algorithm is supported: %#llx\n",
543 				tme_crypto_algs);
544 		mktme_status = MKTME_DISABLED;
545 	}
546 detect_keyid_bits:
547 	keyid_bits = TME_ACTIVATE_KEYID_BITS(tme_activate);
548 	nr_keyids = (1UL << keyid_bits) - 1;
549 	if (nr_keyids) {
550 		pr_info_once("x86/mktme: enabled by BIOS\n");
551 		pr_info_once("x86/mktme: %d KeyIDs available\n", nr_keyids);
552 	} else {
553 		pr_info_once("x86/mktme: disabled by BIOS\n");
554 	}
555 
556 	if (mktme_status == MKTME_UNINITIALIZED) {
557 		/* MKTME is usable */
558 		mktme_status = MKTME_ENABLED;
559 	}
560 
561 	/*
562 	 * KeyID bits effectively lower the number of physical address
563 	 * bits.  Update cpuinfo_x86::x86_phys_bits accordingly.
564 	 */
565 	c->x86_phys_bits -= keyid_bits;
566 }
567 
568 static void init_cpuid_fault(struct cpuinfo_x86 *c)
569 {
570 	u64 msr;
571 
572 	if (!rdmsrl_safe(MSR_PLATFORM_INFO, &msr)) {
573 		if (msr & MSR_PLATFORM_INFO_CPUID_FAULT)
574 			set_cpu_cap(c, X86_FEATURE_CPUID_FAULT);
575 	}
576 }
577 
578 static void init_intel_misc_features(struct cpuinfo_x86 *c)
579 {
580 	u64 msr;
581 
582 	if (rdmsrl_safe(MSR_MISC_FEATURES_ENABLES, &msr))
583 		return;
584 
585 	/* Clear all MISC features */
586 	this_cpu_write(msr_misc_features_shadow, 0);
587 
588 	/* Check features and update capabilities and shadow control bits */
589 	init_cpuid_fault(c);
590 	probe_xeon_phi_r3mwait(c);
591 
592 	msr = this_cpu_read(msr_misc_features_shadow);
593 	wrmsrl(MSR_MISC_FEATURES_ENABLES, msr);
594 }
595 
596 static void split_lock_init(void);
597 
598 static void init_intel(struct cpuinfo_x86 *c)
599 {
600 	early_init_intel(c);
601 
602 	intel_workarounds(c);
603 
604 	/*
605 	 * Detect the extended topology information if available. This
606 	 * will reinitialise the initial_apicid which will be used
607 	 * in init_intel_cacheinfo()
608 	 */
609 	detect_extended_topology(c);
610 
611 	if (!cpu_has(c, X86_FEATURE_XTOPOLOGY)) {
612 		/*
613 		 * let's use the legacy cpuid vector 0x1 and 0x4 for topology
614 		 * detection.
615 		 */
616 		detect_num_cpu_cores(c);
617 #ifdef CONFIG_X86_32
618 		detect_ht(c);
619 #endif
620 	}
621 
622 	init_intel_cacheinfo(c);
623 
624 	if (c->cpuid_level > 9) {
625 		unsigned eax = cpuid_eax(10);
626 		/* Check for version and the number of counters */
627 		if ((eax & 0xff) && (((eax>>8) & 0xff) > 1))
628 			set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
629 	}
630 
631 	if (cpu_has(c, X86_FEATURE_XMM2))
632 		set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
633 
634 	if (boot_cpu_has(X86_FEATURE_DS)) {
635 		unsigned int l1, l2;
636 
637 		rdmsr(MSR_IA32_MISC_ENABLE, l1, l2);
638 		if (!(l1 & (1<<11)))
639 			set_cpu_cap(c, X86_FEATURE_BTS);
640 		if (!(l1 & (1<<12)))
641 			set_cpu_cap(c, X86_FEATURE_PEBS);
642 	}
643 
644 	if (c->x86 == 6 && boot_cpu_has(X86_FEATURE_CLFLUSH) &&
645 	    (c->x86_model == 29 || c->x86_model == 46 || c->x86_model == 47))
646 		set_cpu_bug(c, X86_BUG_CLFLUSH_MONITOR);
647 
648 	if (c->x86 == 6 && boot_cpu_has(X86_FEATURE_MWAIT) &&
649 		((c->x86_model == INTEL_FAM6_ATOM_GOLDMONT)))
650 		set_cpu_bug(c, X86_BUG_MONITOR);
651 
652 #ifdef CONFIG_X86_64
653 	if (c->x86 == 15)
654 		c->x86_cache_alignment = c->x86_clflush_size * 2;
655 	if (c->x86 == 6)
656 		set_cpu_cap(c, X86_FEATURE_REP_GOOD);
657 #else
658 	/*
659 	 * Names for the Pentium II/Celeron processors
660 	 * detectable only by also checking the cache size.
661 	 * Dixon is NOT a Celeron.
662 	 */
663 	if (c->x86 == 6) {
664 		unsigned int l2 = c->x86_cache_size;
665 		char *p = NULL;
666 
667 		switch (c->x86_model) {
668 		case 5:
669 			if (l2 == 0)
670 				p = "Celeron (Covington)";
671 			else if (l2 == 256)
672 				p = "Mobile Pentium II (Dixon)";
673 			break;
674 
675 		case 6:
676 			if (l2 == 128)
677 				p = "Celeron (Mendocino)";
678 			else if (c->x86_stepping == 0 || c->x86_stepping == 5)
679 				p = "Celeron-A";
680 			break;
681 
682 		case 8:
683 			if (l2 == 128)
684 				p = "Celeron (Coppermine)";
685 			break;
686 		}
687 
688 		if (p)
689 			strcpy(c->x86_model_id, p);
690 	}
691 
692 	if (c->x86 == 15)
693 		set_cpu_cap(c, X86_FEATURE_P4);
694 	if (c->x86 == 6)
695 		set_cpu_cap(c, X86_FEATURE_P3);
696 #endif
697 
698 	/* Work around errata */
699 	srat_detect_node(c);
700 
701 	init_ia32_feat_ctl(c);
702 
703 	if (cpu_has(c, X86_FEATURE_TME))
704 		detect_tme(c);
705 
706 	init_intel_misc_features(c);
707 
708 	if (tsx_ctrl_state == TSX_CTRL_ENABLE)
709 		tsx_enable();
710 	if (tsx_ctrl_state == TSX_CTRL_DISABLE)
711 		tsx_disable();
712 
713 	split_lock_init();
714 }
715 
716 #ifdef CONFIG_X86_32
717 static unsigned int intel_size_cache(struct cpuinfo_x86 *c, unsigned int size)
718 {
719 	/*
720 	 * Intel PIII Tualatin. This comes in two flavours.
721 	 * One has 256kb of cache, the other 512. We have no way
722 	 * to determine which, so we use a boottime override
723 	 * for the 512kb model, and assume 256 otherwise.
724 	 */
725 	if ((c->x86 == 6) && (c->x86_model == 11) && (size == 0))
726 		size = 256;
727 
728 	/*
729 	 * Intel Quark SoC X1000 contains a 4-way set associative
730 	 * 16K cache with a 16 byte cache line and 256 lines per tag
731 	 */
732 	if ((c->x86 == 5) && (c->x86_model == 9))
733 		size = 16;
734 	return size;
735 }
736 #endif
737 
738 #define TLB_INST_4K	0x01
739 #define TLB_INST_4M	0x02
740 #define TLB_INST_2M_4M	0x03
741 
742 #define TLB_INST_ALL	0x05
743 #define TLB_INST_1G	0x06
744 
745 #define TLB_DATA_4K	0x11
746 #define TLB_DATA_4M	0x12
747 #define TLB_DATA_2M_4M	0x13
748 #define TLB_DATA_4K_4M	0x14
749 
750 #define TLB_DATA_1G	0x16
751 
752 #define TLB_DATA0_4K	0x21
753 #define TLB_DATA0_4M	0x22
754 #define TLB_DATA0_2M_4M	0x23
755 
756 #define STLB_4K		0x41
757 #define STLB_4K_2M	0x42
758 
759 static const struct _tlb_table intel_tlb_table[] = {
760 	{ 0x01, TLB_INST_4K,		32,	" TLB_INST 4 KByte pages, 4-way set associative" },
761 	{ 0x02, TLB_INST_4M,		2,	" TLB_INST 4 MByte pages, full associative" },
762 	{ 0x03, TLB_DATA_4K,		64,	" TLB_DATA 4 KByte pages, 4-way set associative" },
763 	{ 0x04, TLB_DATA_4M,		8,	" TLB_DATA 4 MByte pages, 4-way set associative" },
764 	{ 0x05, TLB_DATA_4M,		32,	" TLB_DATA 4 MByte pages, 4-way set associative" },
765 	{ 0x0b, TLB_INST_4M,		4,	" TLB_INST 4 MByte pages, 4-way set associative" },
766 	{ 0x4f, TLB_INST_4K,		32,	" TLB_INST 4 KByte pages" },
767 	{ 0x50, TLB_INST_ALL,		64,	" TLB_INST 4 KByte and 2-MByte or 4-MByte pages" },
768 	{ 0x51, TLB_INST_ALL,		128,	" TLB_INST 4 KByte and 2-MByte or 4-MByte pages" },
769 	{ 0x52, TLB_INST_ALL,		256,	" TLB_INST 4 KByte and 2-MByte or 4-MByte pages" },
770 	{ 0x55, TLB_INST_2M_4M,		7,	" TLB_INST 2-MByte or 4-MByte pages, fully associative" },
771 	{ 0x56, TLB_DATA0_4M,		16,	" TLB_DATA0 4 MByte pages, 4-way set associative" },
772 	{ 0x57, TLB_DATA0_4K,		16,	" TLB_DATA0 4 KByte pages, 4-way associative" },
773 	{ 0x59, TLB_DATA0_4K,		16,	" TLB_DATA0 4 KByte pages, fully associative" },
774 	{ 0x5a, TLB_DATA0_2M_4M,	32,	" TLB_DATA0 2-MByte or 4 MByte pages, 4-way set associative" },
775 	{ 0x5b, TLB_DATA_4K_4M,		64,	" TLB_DATA 4 KByte and 4 MByte pages" },
776 	{ 0x5c, TLB_DATA_4K_4M,		128,	" TLB_DATA 4 KByte and 4 MByte pages" },
777 	{ 0x5d, TLB_DATA_4K_4M,		256,	" TLB_DATA 4 KByte and 4 MByte pages" },
778 	{ 0x61, TLB_INST_4K,		48,	" TLB_INST 4 KByte pages, full associative" },
779 	{ 0x63, TLB_DATA_1G,		4,	" TLB_DATA 1 GByte pages, 4-way set associative" },
780 	{ 0x6b, TLB_DATA_4K,		256,	" TLB_DATA 4 KByte pages, 8-way associative" },
781 	{ 0x6c, TLB_DATA_2M_4M,		128,	" TLB_DATA 2 MByte or 4 MByte pages, 8-way associative" },
782 	{ 0x6d, TLB_DATA_1G,		16,	" TLB_DATA 1 GByte pages, fully associative" },
783 	{ 0x76, TLB_INST_2M_4M,		8,	" TLB_INST 2-MByte or 4-MByte pages, fully associative" },
784 	{ 0xb0, TLB_INST_4K,		128,	" TLB_INST 4 KByte pages, 4-way set associative" },
785 	{ 0xb1, TLB_INST_2M_4M,		4,	" TLB_INST 2M pages, 4-way, 8 entries or 4M pages, 4-way entries" },
786 	{ 0xb2, TLB_INST_4K,		64,	" TLB_INST 4KByte pages, 4-way set associative" },
787 	{ 0xb3, TLB_DATA_4K,		128,	" TLB_DATA 4 KByte pages, 4-way set associative" },
788 	{ 0xb4, TLB_DATA_4K,		256,	" TLB_DATA 4 KByte pages, 4-way associative" },
789 	{ 0xb5, TLB_INST_4K,		64,	" TLB_INST 4 KByte pages, 8-way set associative" },
790 	{ 0xb6, TLB_INST_4K,		128,	" TLB_INST 4 KByte pages, 8-way set associative" },
791 	{ 0xba, TLB_DATA_4K,		64,	" TLB_DATA 4 KByte pages, 4-way associative" },
792 	{ 0xc0, TLB_DATA_4K_4M,		8,	" TLB_DATA 4 KByte and 4 MByte pages, 4-way associative" },
793 	{ 0xc1, STLB_4K_2M,		1024,	" STLB 4 KByte and 2 MByte pages, 8-way associative" },
794 	{ 0xc2, TLB_DATA_2M_4M,		16,	" TLB_DATA 2 MByte/4MByte pages, 4-way associative" },
795 	{ 0xca, STLB_4K,		512,	" STLB 4 KByte pages, 4-way associative" },
796 	{ 0x00, 0, 0 }
797 };
798 
799 static void intel_tlb_lookup(const unsigned char desc)
800 {
801 	unsigned char k;
802 	if (desc == 0)
803 		return;
804 
805 	/* look up this descriptor in the table */
806 	for (k = 0; intel_tlb_table[k].descriptor != desc &&
807 	     intel_tlb_table[k].descriptor != 0; k++)
808 		;
809 
810 	if (intel_tlb_table[k].tlb_type == 0)
811 		return;
812 
813 	switch (intel_tlb_table[k].tlb_type) {
814 	case STLB_4K:
815 		if (tlb_lli_4k[ENTRIES] < intel_tlb_table[k].entries)
816 			tlb_lli_4k[ENTRIES] = intel_tlb_table[k].entries;
817 		if (tlb_lld_4k[ENTRIES] < intel_tlb_table[k].entries)
818 			tlb_lld_4k[ENTRIES] = intel_tlb_table[k].entries;
819 		break;
820 	case STLB_4K_2M:
821 		if (tlb_lli_4k[ENTRIES] < intel_tlb_table[k].entries)
822 			tlb_lli_4k[ENTRIES] = intel_tlb_table[k].entries;
823 		if (tlb_lld_4k[ENTRIES] < intel_tlb_table[k].entries)
824 			tlb_lld_4k[ENTRIES] = intel_tlb_table[k].entries;
825 		if (tlb_lli_2m[ENTRIES] < intel_tlb_table[k].entries)
826 			tlb_lli_2m[ENTRIES] = intel_tlb_table[k].entries;
827 		if (tlb_lld_2m[ENTRIES] < intel_tlb_table[k].entries)
828 			tlb_lld_2m[ENTRIES] = intel_tlb_table[k].entries;
829 		if (tlb_lli_4m[ENTRIES] < intel_tlb_table[k].entries)
830 			tlb_lli_4m[ENTRIES] = intel_tlb_table[k].entries;
831 		if (tlb_lld_4m[ENTRIES] < intel_tlb_table[k].entries)
832 			tlb_lld_4m[ENTRIES] = intel_tlb_table[k].entries;
833 		break;
834 	case TLB_INST_ALL:
835 		if (tlb_lli_4k[ENTRIES] < intel_tlb_table[k].entries)
836 			tlb_lli_4k[ENTRIES] = intel_tlb_table[k].entries;
837 		if (tlb_lli_2m[ENTRIES] < intel_tlb_table[k].entries)
838 			tlb_lli_2m[ENTRIES] = intel_tlb_table[k].entries;
839 		if (tlb_lli_4m[ENTRIES] < intel_tlb_table[k].entries)
840 			tlb_lli_4m[ENTRIES] = intel_tlb_table[k].entries;
841 		break;
842 	case TLB_INST_4K:
843 		if (tlb_lli_4k[ENTRIES] < intel_tlb_table[k].entries)
844 			tlb_lli_4k[ENTRIES] = intel_tlb_table[k].entries;
845 		break;
846 	case TLB_INST_4M:
847 		if (tlb_lli_4m[ENTRIES] < intel_tlb_table[k].entries)
848 			tlb_lli_4m[ENTRIES] = intel_tlb_table[k].entries;
849 		break;
850 	case TLB_INST_2M_4M:
851 		if (tlb_lli_2m[ENTRIES] < intel_tlb_table[k].entries)
852 			tlb_lli_2m[ENTRIES] = intel_tlb_table[k].entries;
853 		if (tlb_lli_4m[ENTRIES] < intel_tlb_table[k].entries)
854 			tlb_lli_4m[ENTRIES] = intel_tlb_table[k].entries;
855 		break;
856 	case TLB_DATA_4K:
857 	case TLB_DATA0_4K:
858 		if (tlb_lld_4k[ENTRIES] < intel_tlb_table[k].entries)
859 			tlb_lld_4k[ENTRIES] = intel_tlb_table[k].entries;
860 		break;
861 	case TLB_DATA_4M:
862 	case TLB_DATA0_4M:
863 		if (tlb_lld_4m[ENTRIES] < intel_tlb_table[k].entries)
864 			tlb_lld_4m[ENTRIES] = intel_tlb_table[k].entries;
865 		break;
866 	case TLB_DATA_2M_4M:
867 	case TLB_DATA0_2M_4M:
868 		if (tlb_lld_2m[ENTRIES] < intel_tlb_table[k].entries)
869 			tlb_lld_2m[ENTRIES] = intel_tlb_table[k].entries;
870 		if (tlb_lld_4m[ENTRIES] < intel_tlb_table[k].entries)
871 			tlb_lld_4m[ENTRIES] = intel_tlb_table[k].entries;
872 		break;
873 	case TLB_DATA_4K_4M:
874 		if (tlb_lld_4k[ENTRIES] < intel_tlb_table[k].entries)
875 			tlb_lld_4k[ENTRIES] = intel_tlb_table[k].entries;
876 		if (tlb_lld_4m[ENTRIES] < intel_tlb_table[k].entries)
877 			tlb_lld_4m[ENTRIES] = intel_tlb_table[k].entries;
878 		break;
879 	case TLB_DATA_1G:
880 		if (tlb_lld_1g[ENTRIES] < intel_tlb_table[k].entries)
881 			tlb_lld_1g[ENTRIES] = intel_tlb_table[k].entries;
882 		break;
883 	}
884 }
885 
886 static void intel_detect_tlb(struct cpuinfo_x86 *c)
887 {
888 	int i, j, n;
889 	unsigned int regs[4];
890 	unsigned char *desc = (unsigned char *)regs;
891 
892 	if (c->cpuid_level < 2)
893 		return;
894 
895 	/* Number of times to iterate */
896 	n = cpuid_eax(2) & 0xFF;
897 
898 	for (i = 0 ; i < n ; i++) {
899 		cpuid(2, &regs[0], &regs[1], &regs[2], &regs[3]);
900 
901 		/* If bit 31 is set, this is an unknown format */
902 		for (j = 0 ; j < 3 ; j++)
903 			if (regs[j] & (1 << 31))
904 				regs[j] = 0;
905 
906 		/* Byte 0 is level count, not a descriptor */
907 		for (j = 1 ; j < 16 ; j++)
908 			intel_tlb_lookup(desc[j]);
909 	}
910 }
911 
912 static const struct cpu_dev intel_cpu_dev = {
913 	.c_vendor	= "Intel",
914 	.c_ident	= { "GenuineIntel" },
915 #ifdef CONFIG_X86_32
916 	.legacy_models = {
917 		{ .family = 4, .model_names =
918 		  {
919 			  [0] = "486 DX-25/33",
920 			  [1] = "486 DX-50",
921 			  [2] = "486 SX",
922 			  [3] = "486 DX/2",
923 			  [4] = "486 SL",
924 			  [5] = "486 SX/2",
925 			  [7] = "486 DX/2-WB",
926 			  [8] = "486 DX/4",
927 			  [9] = "486 DX/4-WB"
928 		  }
929 		},
930 		{ .family = 5, .model_names =
931 		  {
932 			  [0] = "Pentium 60/66 A-step",
933 			  [1] = "Pentium 60/66",
934 			  [2] = "Pentium 75 - 200",
935 			  [3] = "OverDrive PODP5V83",
936 			  [4] = "Pentium MMX",
937 			  [7] = "Mobile Pentium 75 - 200",
938 			  [8] = "Mobile Pentium MMX",
939 			  [9] = "Quark SoC X1000",
940 		  }
941 		},
942 		{ .family = 6, .model_names =
943 		  {
944 			  [0] = "Pentium Pro A-step",
945 			  [1] = "Pentium Pro",
946 			  [3] = "Pentium II (Klamath)",
947 			  [4] = "Pentium II (Deschutes)",
948 			  [5] = "Pentium II (Deschutes)",
949 			  [6] = "Mobile Pentium II",
950 			  [7] = "Pentium III (Katmai)",
951 			  [8] = "Pentium III (Coppermine)",
952 			  [10] = "Pentium III (Cascades)",
953 			  [11] = "Pentium III (Tualatin)",
954 		  }
955 		},
956 		{ .family = 15, .model_names =
957 		  {
958 			  [0] = "Pentium 4 (Unknown)",
959 			  [1] = "Pentium 4 (Willamette)",
960 			  [2] = "Pentium 4 (Northwood)",
961 			  [4] = "Pentium 4 (Foster)",
962 			  [5] = "Pentium 4 (Foster)",
963 		  }
964 		},
965 	},
966 	.legacy_cache_size = intel_size_cache,
967 #endif
968 	.c_detect_tlb	= intel_detect_tlb,
969 	.c_early_init   = early_init_intel,
970 	.c_bsp_init	= bsp_init_intel,
971 	.c_init		= init_intel,
972 	.c_x86_vendor	= X86_VENDOR_INTEL,
973 };
974 
975 cpu_dev_register(intel_cpu_dev);
976 
977 #undef pr_fmt
978 #define pr_fmt(fmt) "x86/split lock detection: " fmt
979 
980 static const struct {
981 	const char			*option;
982 	enum split_lock_detect_state	state;
983 } sld_options[] __initconst = {
984 	{ "off",	sld_off   },
985 	{ "warn",	sld_warn  },
986 	{ "fatal",	sld_fatal },
987 };
988 
989 static inline bool match_option(const char *arg, int arglen, const char *opt)
990 {
991 	int len = strlen(opt);
992 
993 	return len == arglen && !strncmp(arg, opt, len);
994 }
995 
996 static bool split_lock_verify_msr(bool on)
997 {
998 	u64 ctrl, tmp;
999 
1000 	if (rdmsrl_safe(MSR_TEST_CTRL, &ctrl))
1001 		return false;
1002 	if (on)
1003 		ctrl |= MSR_TEST_CTRL_SPLIT_LOCK_DETECT;
1004 	else
1005 		ctrl &= ~MSR_TEST_CTRL_SPLIT_LOCK_DETECT;
1006 	if (wrmsrl_safe(MSR_TEST_CTRL, ctrl))
1007 		return false;
1008 	rdmsrl(MSR_TEST_CTRL, tmp);
1009 	return ctrl == tmp;
1010 }
1011 
1012 static void __init split_lock_setup(void)
1013 {
1014 	enum split_lock_detect_state state = sld_warn;
1015 	char arg[20];
1016 	int i, ret;
1017 
1018 	if (!split_lock_verify_msr(false)) {
1019 		pr_info("MSR access failed: Disabled\n");
1020 		return;
1021 	}
1022 
1023 	ret = cmdline_find_option(boot_command_line, "split_lock_detect",
1024 				  arg, sizeof(arg));
1025 	if (ret >= 0) {
1026 		for (i = 0; i < ARRAY_SIZE(sld_options); i++) {
1027 			if (match_option(arg, ret, sld_options[i].option)) {
1028 				state = sld_options[i].state;
1029 				break;
1030 			}
1031 		}
1032 	}
1033 
1034 	switch (state) {
1035 	case sld_off:
1036 		pr_info("disabled\n");
1037 		return;
1038 	case sld_warn:
1039 		pr_info("warning about user-space split_locks\n");
1040 		break;
1041 	case sld_fatal:
1042 		pr_info("sending SIGBUS on user-space split_locks\n");
1043 		break;
1044 	}
1045 
1046 	rdmsrl(MSR_TEST_CTRL, msr_test_ctrl_cache);
1047 
1048 	if (!split_lock_verify_msr(true)) {
1049 		pr_info("MSR access failed: Disabled\n");
1050 		return;
1051 	}
1052 
1053 	sld_state = state;
1054 	setup_force_cpu_cap(X86_FEATURE_SPLIT_LOCK_DETECT);
1055 }
1056 
1057 /*
1058  * MSR_TEST_CTRL is per core, but we treat it like a per CPU MSR. Locking
1059  * is not implemented as one thread could undo the setting of the other
1060  * thread immediately after dropping the lock anyway.
1061  */
1062 static void sld_update_msr(bool on)
1063 {
1064 	u64 test_ctrl_val = msr_test_ctrl_cache;
1065 
1066 	if (on)
1067 		test_ctrl_val |= MSR_TEST_CTRL_SPLIT_LOCK_DETECT;
1068 
1069 	wrmsrl(MSR_TEST_CTRL, test_ctrl_val);
1070 }
1071 
1072 static void split_lock_init(void)
1073 {
1074 	split_lock_verify_msr(sld_state != sld_off);
1075 }
1076 
1077 static void split_lock_warn(unsigned long ip)
1078 {
1079 	pr_warn_ratelimited("#AC: %s/%d took a split_lock trap at address: 0x%lx\n",
1080 			    current->comm, current->pid, ip);
1081 
1082 	/*
1083 	 * Disable the split lock detection for this task so it can make
1084 	 * progress and set TIF_SLD so the detection is re-enabled via
1085 	 * switch_to_sld() when the task is scheduled out.
1086 	 */
1087 	sld_update_msr(false);
1088 	set_tsk_thread_flag(current, TIF_SLD);
1089 }
1090 
1091 bool handle_guest_split_lock(unsigned long ip)
1092 {
1093 	if (sld_state == sld_warn) {
1094 		split_lock_warn(ip);
1095 		return true;
1096 	}
1097 
1098 	pr_warn_once("#AC: %s/%d %s split_lock trap at address: 0x%lx\n",
1099 		     current->comm, current->pid,
1100 		     sld_state == sld_fatal ? "fatal" : "bogus", ip);
1101 
1102 	current->thread.error_code = 0;
1103 	current->thread.trap_nr = X86_TRAP_AC;
1104 	force_sig_fault(SIGBUS, BUS_ADRALN, NULL);
1105 	return false;
1106 }
1107 EXPORT_SYMBOL_GPL(handle_guest_split_lock);
1108 
1109 bool handle_user_split_lock(struct pt_regs *regs, long error_code)
1110 {
1111 	if ((regs->flags & X86_EFLAGS_AC) || sld_state == sld_fatal)
1112 		return false;
1113 	split_lock_warn(regs->ip);
1114 	return true;
1115 }
1116 
1117 /*
1118  * This function is called only when switching between tasks with
1119  * different split-lock detection modes. It sets the MSR for the
1120  * mode of the new task. This is right most of the time, but since
1121  * the MSR is shared by hyperthreads on a physical core there can
1122  * be glitches when the two threads need different modes.
1123  */
1124 void switch_to_sld(unsigned long tifn)
1125 {
1126 	sld_update_msr(!(tifn & _TIF_SLD));
1127 }
1128 
1129 /*
1130  * Bits in the IA32_CORE_CAPABILITIES are not architectural, so they should
1131  * only be trusted if it is confirmed that a CPU model implements a
1132  * specific feature at a particular bit position.
1133  *
1134  * The possible driver data field values:
1135  *
1136  * - 0: CPU models that are known to have the per-core split-lock detection
1137  *	feature even though they do not enumerate IA32_CORE_CAPABILITIES.
1138  *
1139  * - 1: CPU models which may enumerate IA32_CORE_CAPABILITIES and if so use
1140  *      bit 5 to enumerate the per-core split-lock detection feature.
1141  */
1142 static const struct x86_cpu_id split_lock_cpu_ids[] __initconst = {
1143 	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X,		0),
1144 	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_L,		0),
1145 	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D,		0),
1146 	X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT,	1),
1147 	X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT_D,	1),
1148 	X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT_L,	1),
1149 	X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE_L,		1),
1150 	X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE,		1),
1151 	{}
1152 };
1153 
1154 void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c)
1155 {
1156 	const struct x86_cpu_id *m;
1157 	u64 ia32_core_caps;
1158 
1159 	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
1160 		return;
1161 
1162 	m = x86_match_cpu(split_lock_cpu_ids);
1163 	if (!m)
1164 		return;
1165 
1166 	switch (m->driver_data) {
1167 	case 0:
1168 		break;
1169 	case 1:
1170 		if (!cpu_has(c, X86_FEATURE_CORE_CAPABILITIES))
1171 			return;
1172 		rdmsrl(MSR_IA32_CORE_CAPS, ia32_core_caps);
1173 		if (!(ia32_core_caps & MSR_IA32_CORE_CAPS_SPLIT_LOCK_DETECT))
1174 			return;
1175 		break;
1176 	default:
1177 		return;
1178 	}
1179 
1180 	split_lock_setup();
1181 }
1182