1 // SPDX-License-Identifier: GPL-2.0-only 2 /* cpu_feature_enabled() cannot be used this early */ 3 #define USE_EARLY_PGTABLE_L5 4 5 #include <linux/memblock.h> 6 #include <linux/linkage.h> 7 #include <linux/bitops.h> 8 #include <linux/kernel.h> 9 #include <linux/export.h> 10 #include <linux/percpu.h> 11 #include <linux/string.h> 12 #include <linux/ctype.h> 13 #include <linux/delay.h> 14 #include <linux/sched/mm.h> 15 #include <linux/sched/clock.h> 16 #include <linux/sched/task.h> 17 #include <linux/sched/smt.h> 18 #include <linux/init.h> 19 #include <linux/kprobes.h> 20 #include <linux/kgdb.h> 21 #include <linux/mem_encrypt.h> 22 #include <linux/smp.h> 23 #include <linux/cpu.h> 24 #include <linux/io.h> 25 #include <linux/syscore_ops.h> 26 #include <linux/pgtable.h> 27 #include <linux/stackprotector.h> 28 #include <linux/utsname.h> 29 30 #include <asm/alternative.h> 31 #include <asm/cmdline.h> 32 #include <asm/perf_event.h> 33 #include <asm/mmu_context.h> 34 #include <asm/doublefault.h> 35 #include <asm/archrandom.h> 36 #include <asm/hypervisor.h> 37 #include <asm/processor.h> 38 #include <asm/tlbflush.h> 39 #include <asm/debugreg.h> 40 #include <asm/sections.h> 41 #include <asm/vsyscall.h> 42 #include <linux/topology.h> 43 #include <linux/cpumask.h> 44 #include <linux/atomic.h> 45 #include <asm/proto.h> 46 #include <asm/setup.h> 47 #include <asm/apic.h> 48 #include <asm/desc.h> 49 #include <asm/fpu/api.h> 50 #include <asm/mtrr.h> 51 #include <asm/hwcap2.h> 52 #include <linux/numa.h> 53 #include <asm/numa.h> 54 #include <asm/asm.h> 55 #include <asm/bugs.h> 56 #include <asm/cpu.h> 57 #include <asm/mce.h> 58 #include <asm/msr.h> 59 #include <asm/cacheinfo.h> 60 #include <asm/memtype.h> 61 #include <asm/microcode.h> 62 #include <asm/microcode_intel.h> 63 #include <asm/intel-family.h> 64 #include <asm/cpu_device_id.h> 65 #include <asm/uv/uv.h> 66 #include <asm/set_memory.h> 67 #include <asm/traps.h> 68 #include <asm/sev.h> 69 70 #include "cpu.h" 71 72 u32 elf_hwcap2 __read_mostly; 73 74 /* Number of siblings per CPU package */ 75 int smp_num_siblings = 1; 76 EXPORT_SYMBOL(smp_num_siblings); 77 78 /* Last level cache ID of each logical CPU */ 79 DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id) = BAD_APICID; 80 81 u16 get_llc_id(unsigned int cpu) 82 { 83 return per_cpu(cpu_llc_id, cpu); 84 } 85 EXPORT_SYMBOL_GPL(get_llc_id); 86 87 /* L2 cache ID of each logical CPU */ 88 DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_l2c_id) = BAD_APICID; 89 90 static struct ppin_info { 91 int feature; 92 int msr_ppin_ctl; 93 int msr_ppin; 94 } ppin_info[] = { 95 [X86_VENDOR_INTEL] = { 96 .feature = X86_FEATURE_INTEL_PPIN, 97 .msr_ppin_ctl = MSR_PPIN_CTL, 98 .msr_ppin = MSR_PPIN 99 }, 100 [X86_VENDOR_AMD] = { 101 .feature = X86_FEATURE_AMD_PPIN, 102 .msr_ppin_ctl = MSR_AMD_PPIN_CTL, 103 .msr_ppin = MSR_AMD_PPIN 104 }, 105 }; 106 107 static const struct x86_cpu_id ppin_cpuids[] = { 108 X86_MATCH_FEATURE(X86_FEATURE_AMD_PPIN, &ppin_info[X86_VENDOR_AMD]), 109 X86_MATCH_FEATURE(X86_FEATURE_INTEL_PPIN, &ppin_info[X86_VENDOR_INTEL]), 110 111 /* Legacy models without CPUID enumeration */ 112 X86_MATCH_INTEL_FAM6_MODEL(IVYBRIDGE_X, &ppin_info[X86_VENDOR_INTEL]), 113 X86_MATCH_INTEL_FAM6_MODEL(HASWELL_X, &ppin_info[X86_VENDOR_INTEL]), 114 X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_D, &ppin_info[X86_VENDOR_INTEL]), 115 X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_X, &ppin_info[X86_VENDOR_INTEL]), 116 X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_X, &ppin_info[X86_VENDOR_INTEL]), 117 X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X, &ppin_info[X86_VENDOR_INTEL]), 118 X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D, &ppin_info[X86_VENDOR_INTEL]), 119 X86_MATCH_INTEL_FAM6_MODEL(SAPPHIRERAPIDS_X, &ppin_info[X86_VENDOR_INTEL]), 120 X86_MATCH_INTEL_FAM6_MODEL(EMERALDRAPIDS_X, &ppin_info[X86_VENDOR_INTEL]), 121 X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNL, &ppin_info[X86_VENDOR_INTEL]), 122 X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNM, &ppin_info[X86_VENDOR_INTEL]), 123 124 {} 125 }; 126 127 static void ppin_init(struct cpuinfo_x86 *c) 128 { 129 const struct x86_cpu_id *id; 130 unsigned long long val; 131 struct ppin_info *info; 132 133 id = x86_match_cpu(ppin_cpuids); 134 if (!id) 135 return; 136 137 /* 138 * Testing the presence of the MSR is not enough. Need to check 139 * that the PPIN_CTL allows reading of the PPIN. 140 */ 141 info = (struct ppin_info *)id->driver_data; 142 143 if (rdmsrl_safe(info->msr_ppin_ctl, &val)) 144 goto clear_ppin; 145 146 if ((val & 3UL) == 1UL) { 147 /* PPIN locked in disabled mode */ 148 goto clear_ppin; 149 } 150 151 /* If PPIN is disabled, try to enable */ 152 if (!(val & 2UL)) { 153 wrmsrl_safe(info->msr_ppin_ctl, val | 2UL); 154 rdmsrl_safe(info->msr_ppin_ctl, &val); 155 } 156 157 /* Is the enable bit set? */ 158 if (val & 2UL) { 159 c->ppin = __rdmsr(info->msr_ppin); 160 set_cpu_cap(c, info->feature); 161 return; 162 } 163 164 clear_ppin: 165 clear_cpu_cap(c, info->feature); 166 } 167 168 static void default_init(struct cpuinfo_x86 *c) 169 { 170 #ifdef CONFIG_X86_64 171 cpu_detect_cache_sizes(c); 172 #else 173 /* Not much we can do here... */ 174 /* Check if at least it has cpuid */ 175 if (c->cpuid_level == -1) { 176 /* No cpuid. It must be an ancient CPU */ 177 if (c->x86 == 4) 178 strcpy(c->x86_model_id, "486"); 179 else if (c->x86 == 3) 180 strcpy(c->x86_model_id, "386"); 181 } 182 #endif 183 } 184 185 static const struct cpu_dev default_cpu = { 186 .c_init = default_init, 187 .c_vendor = "Unknown", 188 .c_x86_vendor = X86_VENDOR_UNKNOWN, 189 }; 190 191 static const struct cpu_dev *this_cpu = &default_cpu; 192 193 DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = { 194 #ifdef CONFIG_X86_64 195 /* 196 * We need valid kernel segments for data and code in long mode too 197 * IRET will check the segment types kkeil 2000/10/28 198 * Also sysret mandates a special GDT layout 199 * 200 * TLS descriptors are currently at a different place compared to i386. 201 * Hopefully nobody expects them at a fixed place (Wine?) 202 */ 203 [GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(0xc09b, 0, 0xfffff), 204 [GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(0xa09b, 0, 0xfffff), 205 [GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(0xc093, 0, 0xfffff), 206 [GDT_ENTRY_DEFAULT_USER32_CS] = GDT_ENTRY_INIT(0xc0fb, 0, 0xfffff), 207 [GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(0xc0f3, 0, 0xfffff), 208 [GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(0xa0fb, 0, 0xfffff), 209 #else 210 [GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(0xc09a, 0, 0xfffff), 211 [GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff), 212 [GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(0xc0fa, 0, 0xfffff), 213 [GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(0xc0f2, 0, 0xfffff), 214 /* 215 * Segments used for calling PnP BIOS have byte granularity. 216 * They code segments and data segments have fixed 64k limits, 217 * the transfer segment sizes are set at run time. 218 */ 219 /* 32-bit code */ 220 [GDT_ENTRY_PNPBIOS_CS32] = GDT_ENTRY_INIT(0x409a, 0, 0xffff), 221 /* 16-bit code */ 222 [GDT_ENTRY_PNPBIOS_CS16] = GDT_ENTRY_INIT(0x009a, 0, 0xffff), 223 /* 16-bit data */ 224 [GDT_ENTRY_PNPBIOS_DS] = GDT_ENTRY_INIT(0x0092, 0, 0xffff), 225 /* 16-bit data */ 226 [GDT_ENTRY_PNPBIOS_TS1] = GDT_ENTRY_INIT(0x0092, 0, 0), 227 /* 16-bit data */ 228 [GDT_ENTRY_PNPBIOS_TS2] = GDT_ENTRY_INIT(0x0092, 0, 0), 229 /* 230 * The APM segments have byte granularity and their bases 231 * are set at run time. All have 64k limits. 232 */ 233 /* 32-bit code */ 234 [GDT_ENTRY_APMBIOS_BASE] = GDT_ENTRY_INIT(0x409a, 0, 0xffff), 235 /* 16-bit code */ 236 [GDT_ENTRY_APMBIOS_BASE+1] = GDT_ENTRY_INIT(0x009a, 0, 0xffff), 237 /* data */ 238 [GDT_ENTRY_APMBIOS_BASE+2] = GDT_ENTRY_INIT(0x4092, 0, 0xffff), 239 240 [GDT_ENTRY_ESPFIX_SS] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff), 241 [GDT_ENTRY_PERCPU] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff), 242 #endif 243 } }; 244 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page); 245 246 #ifdef CONFIG_X86_64 247 static int __init x86_nopcid_setup(char *s) 248 { 249 /* nopcid doesn't accept parameters */ 250 if (s) 251 return -EINVAL; 252 253 /* do not emit a message if the feature is not present */ 254 if (!boot_cpu_has(X86_FEATURE_PCID)) 255 return 0; 256 257 setup_clear_cpu_cap(X86_FEATURE_PCID); 258 pr_info("nopcid: PCID feature disabled\n"); 259 return 0; 260 } 261 early_param("nopcid", x86_nopcid_setup); 262 #endif 263 264 static int __init x86_noinvpcid_setup(char *s) 265 { 266 /* noinvpcid doesn't accept parameters */ 267 if (s) 268 return -EINVAL; 269 270 /* do not emit a message if the feature is not present */ 271 if (!boot_cpu_has(X86_FEATURE_INVPCID)) 272 return 0; 273 274 setup_clear_cpu_cap(X86_FEATURE_INVPCID); 275 pr_info("noinvpcid: INVPCID feature disabled\n"); 276 return 0; 277 } 278 early_param("noinvpcid", x86_noinvpcid_setup); 279 280 #ifdef CONFIG_X86_32 281 static int cachesize_override = -1; 282 static int disable_x86_serial_nr = 1; 283 284 static int __init cachesize_setup(char *str) 285 { 286 get_option(&str, &cachesize_override); 287 return 1; 288 } 289 __setup("cachesize=", cachesize_setup); 290 291 /* Standard macro to see if a specific flag is changeable */ 292 static inline int flag_is_changeable_p(u32 flag) 293 { 294 u32 f1, f2; 295 296 /* 297 * Cyrix and IDT cpus allow disabling of CPUID 298 * so the code below may return different results 299 * when it is executed before and after enabling 300 * the CPUID. Add "volatile" to not allow gcc to 301 * optimize the subsequent calls to this function. 302 */ 303 asm volatile ("pushfl \n\t" 304 "pushfl \n\t" 305 "popl %0 \n\t" 306 "movl %0, %1 \n\t" 307 "xorl %2, %0 \n\t" 308 "pushl %0 \n\t" 309 "popfl \n\t" 310 "pushfl \n\t" 311 "popl %0 \n\t" 312 "popfl \n\t" 313 314 : "=&r" (f1), "=&r" (f2) 315 : "ir" (flag)); 316 317 return ((f1^f2) & flag) != 0; 318 } 319 320 /* Probe for the CPUID instruction */ 321 int have_cpuid_p(void) 322 { 323 return flag_is_changeable_p(X86_EFLAGS_ID); 324 } 325 326 static void squash_the_stupid_serial_number(struct cpuinfo_x86 *c) 327 { 328 unsigned long lo, hi; 329 330 if (!cpu_has(c, X86_FEATURE_PN) || !disable_x86_serial_nr) 331 return; 332 333 /* Disable processor serial number: */ 334 335 rdmsr(MSR_IA32_BBL_CR_CTL, lo, hi); 336 lo |= 0x200000; 337 wrmsr(MSR_IA32_BBL_CR_CTL, lo, hi); 338 339 pr_notice("CPU serial number disabled.\n"); 340 clear_cpu_cap(c, X86_FEATURE_PN); 341 342 /* Disabling the serial number may affect the cpuid level */ 343 c->cpuid_level = cpuid_eax(0); 344 } 345 346 static int __init x86_serial_nr_setup(char *s) 347 { 348 disable_x86_serial_nr = 0; 349 return 1; 350 } 351 __setup("serialnumber", x86_serial_nr_setup); 352 #else 353 static inline int flag_is_changeable_p(u32 flag) 354 { 355 return 1; 356 } 357 static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c) 358 { 359 } 360 #endif 361 362 static __always_inline void setup_smep(struct cpuinfo_x86 *c) 363 { 364 if (cpu_has(c, X86_FEATURE_SMEP)) 365 cr4_set_bits(X86_CR4_SMEP); 366 } 367 368 static __always_inline void setup_smap(struct cpuinfo_x86 *c) 369 { 370 unsigned long eflags = native_save_fl(); 371 372 /* This should have been cleared long ago */ 373 BUG_ON(eflags & X86_EFLAGS_AC); 374 375 if (cpu_has(c, X86_FEATURE_SMAP)) 376 cr4_set_bits(X86_CR4_SMAP); 377 } 378 379 static __always_inline void setup_umip(struct cpuinfo_x86 *c) 380 { 381 /* Check the boot processor, plus build option for UMIP. */ 382 if (!cpu_feature_enabled(X86_FEATURE_UMIP)) 383 goto out; 384 385 /* Check the current processor's cpuid bits. */ 386 if (!cpu_has(c, X86_FEATURE_UMIP)) 387 goto out; 388 389 cr4_set_bits(X86_CR4_UMIP); 390 391 pr_info_once("x86/cpu: User Mode Instruction Prevention (UMIP) activated\n"); 392 393 return; 394 395 out: 396 /* 397 * Make sure UMIP is disabled in case it was enabled in a 398 * previous boot (e.g., via kexec). 399 */ 400 cr4_clear_bits(X86_CR4_UMIP); 401 } 402 403 /* These bits should not change their value after CPU init is finished. */ 404 static const unsigned long cr4_pinned_mask = 405 X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_UMIP | 406 X86_CR4_FSGSBASE | X86_CR4_CET; 407 static DEFINE_STATIC_KEY_FALSE_RO(cr_pinning); 408 static unsigned long cr4_pinned_bits __ro_after_init; 409 410 void native_write_cr0(unsigned long val) 411 { 412 unsigned long bits_missing = 0; 413 414 set_register: 415 asm volatile("mov %0,%%cr0": "+r" (val) : : "memory"); 416 417 if (static_branch_likely(&cr_pinning)) { 418 if (unlikely((val & X86_CR0_WP) != X86_CR0_WP)) { 419 bits_missing = X86_CR0_WP; 420 val |= bits_missing; 421 goto set_register; 422 } 423 /* Warn after we've set the missing bits. */ 424 WARN_ONCE(bits_missing, "CR0 WP bit went missing!?\n"); 425 } 426 } 427 EXPORT_SYMBOL(native_write_cr0); 428 429 void __no_profile native_write_cr4(unsigned long val) 430 { 431 unsigned long bits_changed = 0; 432 433 set_register: 434 asm volatile("mov %0,%%cr4": "+r" (val) : : "memory"); 435 436 if (static_branch_likely(&cr_pinning)) { 437 if (unlikely((val & cr4_pinned_mask) != cr4_pinned_bits)) { 438 bits_changed = (val & cr4_pinned_mask) ^ cr4_pinned_bits; 439 val = (val & ~cr4_pinned_mask) | cr4_pinned_bits; 440 goto set_register; 441 } 442 /* Warn after we've corrected the changed bits. */ 443 WARN_ONCE(bits_changed, "pinned CR4 bits changed: 0x%lx!?\n", 444 bits_changed); 445 } 446 } 447 #if IS_MODULE(CONFIG_LKDTM) 448 EXPORT_SYMBOL_GPL(native_write_cr4); 449 #endif 450 451 void cr4_update_irqsoff(unsigned long set, unsigned long clear) 452 { 453 unsigned long newval, cr4 = this_cpu_read(cpu_tlbstate.cr4); 454 455 lockdep_assert_irqs_disabled(); 456 457 newval = (cr4 & ~clear) | set; 458 if (newval != cr4) { 459 this_cpu_write(cpu_tlbstate.cr4, newval); 460 __write_cr4(newval); 461 } 462 } 463 EXPORT_SYMBOL(cr4_update_irqsoff); 464 465 /* Read the CR4 shadow. */ 466 unsigned long cr4_read_shadow(void) 467 { 468 return this_cpu_read(cpu_tlbstate.cr4); 469 } 470 EXPORT_SYMBOL_GPL(cr4_read_shadow); 471 472 void cr4_init(void) 473 { 474 unsigned long cr4 = __read_cr4(); 475 476 if (boot_cpu_has(X86_FEATURE_PCID)) 477 cr4 |= X86_CR4_PCIDE; 478 if (static_branch_likely(&cr_pinning)) 479 cr4 = (cr4 & ~cr4_pinned_mask) | cr4_pinned_bits; 480 481 __write_cr4(cr4); 482 483 /* Initialize cr4 shadow for this CPU. */ 484 this_cpu_write(cpu_tlbstate.cr4, cr4); 485 } 486 487 /* 488 * Once CPU feature detection is finished (and boot params have been 489 * parsed), record any of the sensitive CR bits that are set, and 490 * enable CR pinning. 491 */ 492 static void __init setup_cr_pinning(void) 493 { 494 cr4_pinned_bits = this_cpu_read(cpu_tlbstate.cr4) & cr4_pinned_mask; 495 static_key_enable(&cr_pinning.key); 496 } 497 498 static __init int x86_nofsgsbase_setup(char *arg) 499 { 500 /* Require an exact match without trailing characters. */ 501 if (strlen(arg)) 502 return 0; 503 504 /* Do not emit a message if the feature is not present. */ 505 if (!boot_cpu_has(X86_FEATURE_FSGSBASE)) 506 return 1; 507 508 setup_clear_cpu_cap(X86_FEATURE_FSGSBASE); 509 pr_info("FSGSBASE disabled via kernel command line\n"); 510 return 1; 511 } 512 __setup("nofsgsbase", x86_nofsgsbase_setup); 513 514 /* 515 * Protection Keys are not available in 32-bit mode. 516 */ 517 static bool pku_disabled; 518 519 static __always_inline void setup_pku(struct cpuinfo_x86 *c) 520 { 521 if (c == &boot_cpu_data) { 522 if (pku_disabled || !cpu_feature_enabled(X86_FEATURE_PKU)) 523 return; 524 /* 525 * Setting CR4.PKE will cause the X86_FEATURE_OSPKE cpuid 526 * bit to be set. Enforce it. 527 */ 528 setup_force_cpu_cap(X86_FEATURE_OSPKE); 529 530 } else if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) { 531 return; 532 } 533 534 cr4_set_bits(X86_CR4_PKE); 535 /* Load the default PKRU value */ 536 pkru_write_default(); 537 } 538 539 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 540 static __init int setup_disable_pku(char *arg) 541 { 542 /* 543 * Do not clear the X86_FEATURE_PKU bit. All of the 544 * runtime checks are against OSPKE so clearing the 545 * bit does nothing. 546 * 547 * This way, we will see "pku" in cpuinfo, but not 548 * "ospke", which is exactly what we want. It shows 549 * that the CPU has PKU, but the OS has not enabled it. 550 * This happens to be exactly how a system would look 551 * if we disabled the config option. 552 */ 553 pr_info("x86: 'nopku' specified, disabling Memory Protection Keys\n"); 554 pku_disabled = true; 555 return 1; 556 } 557 __setup("nopku", setup_disable_pku); 558 #endif 559 560 #ifdef CONFIG_X86_KERNEL_IBT 561 562 __noendbr u64 ibt_save(bool disable) 563 { 564 u64 msr = 0; 565 566 if (cpu_feature_enabled(X86_FEATURE_IBT)) { 567 rdmsrl(MSR_IA32_S_CET, msr); 568 if (disable) 569 wrmsrl(MSR_IA32_S_CET, msr & ~CET_ENDBR_EN); 570 } 571 572 return msr; 573 } 574 575 __noendbr void ibt_restore(u64 save) 576 { 577 u64 msr; 578 579 if (cpu_feature_enabled(X86_FEATURE_IBT)) { 580 rdmsrl(MSR_IA32_S_CET, msr); 581 msr &= ~CET_ENDBR_EN; 582 msr |= (save & CET_ENDBR_EN); 583 wrmsrl(MSR_IA32_S_CET, msr); 584 } 585 } 586 587 #endif 588 589 static __always_inline void setup_cet(struct cpuinfo_x86 *c) 590 { 591 u64 msr = CET_ENDBR_EN; 592 593 if (!HAS_KERNEL_IBT || 594 !cpu_feature_enabled(X86_FEATURE_IBT)) 595 return; 596 597 wrmsrl(MSR_IA32_S_CET, msr); 598 cr4_set_bits(X86_CR4_CET); 599 600 if (!ibt_selftest()) { 601 pr_err("IBT selftest: Failed!\n"); 602 wrmsrl(MSR_IA32_S_CET, 0); 603 setup_clear_cpu_cap(X86_FEATURE_IBT); 604 return; 605 } 606 } 607 608 __noendbr void cet_disable(void) 609 { 610 if (cpu_feature_enabled(X86_FEATURE_IBT)) 611 wrmsrl(MSR_IA32_S_CET, 0); 612 } 613 614 /* 615 * Some CPU features depend on higher CPUID levels, which may not always 616 * be available due to CPUID level capping or broken virtualization 617 * software. Add those features to this table to auto-disable them. 618 */ 619 struct cpuid_dependent_feature { 620 u32 feature; 621 u32 level; 622 }; 623 624 static const struct cpuid_dependent_feature 625 cpuid_dependent_features[] = { 626 { X86_FEATURE_MWAIT, 0x00000005 }, 627 { X86_FEATURE_DCA, 0x00000009 }, 628 { X86_FEATURE_XSAVE, 0x0000000d }, 629 { 0, 0 } 630 }; 631 632 static void filter_cpuid_features(struct cpuinfo_x86 *c, bool warn) 633 { 634 const struct cpuid_dependent_feature *df; 635 636 for (df = cpuid_dependent_features; df->feature; df++) { 637 638 if (!cpu_has(c, df->feature)) 639 continue; 640 /* 641 * Note: cpuid_level is set to -1 if unavailable, but 642 * extended_extended_level is set to 0 if unavailable 643 * and the legitimate extended levels are all negative 644 * when signed; hence the weird messing around with 645 * signs here... 646 */ 647 if (!((s32)df->level < 0 ? 648 (u32)df->level > (u32)c->extended_cpuid_level : 649 (s32)df->level > (s32)c->cpuid_level)) 650 continue; 651 652 clear_cpu_cap(c, df->feature); 653 if (!warn) 654 continue; 655 656 pr_warn("CPU: CPU feature " X86_CAP_FMT " disabled, no CPUID level 0x%x\n", 657 x86_cap_flag(df->feature), df->level); 658 } 659 } 660 661 /* 662 * Naming convention should be: <Name> [(<Codename>)] 663 * This table only is used unless init_<vendor>() below doesn't set it; 664 * in particular, if CPUID levels 0x80000002..4 are supported, this 665 * isn't used 666 */ 667 668 /* Look up CPU names by table lookup. */ 669 static const char *table_lookup_model(struct cpuinfo_x86 *c) 670 { 671 #ifdef CONFIG_X86_32 672 const struct legacy_cpu_model_info *info; 673 674 if (c->x86_model >= 16) 675 return NULL; /* Range check */ 676 677 if (!this_cpu) 678 return NULL; 679 680 info = this_cpu->legacy_models; 681 682 while (info->family) { 683 if (info->family == c->x86) 684 return info->model_names[c->x86_model]; 685 info++; 686 } 687 #endif 688 return NULL; /* Not found */ 689 } 690 691 /* Aligned to unsigned long to avoid split lock in atomic bitmap ops */ 692 __u32 cpu_caps_cleared[NCAPINTS + NBUGINTS] __aligned(sizeof(unsigned long)); 693 __u32 cpu_caps_set[NCAPINTS + NBUGINTS] __aligned(sizeof(unsigned long)); 694 695 #ifdef CONFIG_X86_32 696 /* The 32-bit entry code needs to find cpu_entry_area. */ 697 DEFINE_PER_CPU(struct cpu_entry_area *, cpu_entry_area); 698 #endif 699 700 /* Load the original GDT from the per-cpu structure */ 701 void load_direct_gdt(int cpu) 702 { 703 struct desc_ptr gdt_descr; 704 705 gdt_descr.address = (long)get_cpu_gdt_rw(cpu); 706 gdt_descr.size = GDT_SIZE - 1; 707 load_gdt(&gdt_descr); 708 } 709 EXPORT_SYMBOL_GPL(load_direct_gdt); 710 711 /* Load a fixmap remapping of the per-cpu GDT */ 712 void load_fixmap_gdt(int cpu) 713 { 714 struct desc_ptr gdt_descr; 715 716 gdt_descr.address = (long)get_cpu_gdt_ro(cpu); 717 gdt_descr.size = GDT_SIZE - 1; 718 load_gdt(&gdt_descr); 719 } 720 EXPORT_SYMBOL_GPL(load_fixmap_gdt); 721 722 /** 723 * switch_gdt_and_percpu_base - Switch to direct GDT and runtime per CPU base 724 * @cpu: The CPU number for which this is invoked 725 * 726 * Invoked during early boot to switch from early GDT and early per CPU to 727 * the direct GDT and the runtime per CPU area. On 32-bit the percpu base 728 * switch is implicit by loading the direct GDT. On 64bit this requires 729 * to update GSBASE. 730 */ 731 void __init switch_gdt_and_percpu_base(int cpu) 732 { 733 load_direct_gdt(cpu); 734 735 #ifdef CONFIG_X86_64 736 /* 737 * No need to load %gs. It is already correct. 738 * 739 * Writing %gs on 64bit would zero GSBASE which would make any per 740 * CPU operation up to the point of the wrmsrl() fault. 741 * 742 * Set GSBASE to the new offset. Until the wrmsrl() happens the 743 * early mapping is still valid. That means the GSBASE update will 744 * lose any prior per CPU data which was not copied over in 745 * setup_per_cpu_areas(). 746 * 747 * This works even with stackprotector enabled because the 748 * per CPU stack canary is 0 in both per CPU areas. 749 */ 750 wrmsrl(MSR_GS_BASE, cpu_kernelmode_gs_base(cpu)); 751 #else 752 /* 753 * %fs is already set to __KERNEL_PERCPU, but after switching GDT 754 * it is required to load FS again so that the 'hidden' part is 755 * updated from the new GDT. Up to this point the early per CPU 756 * translation is active. Any content of the early per CPU data 757 * which was not copied over in setup_per_cpu_areas() is lost. 758 */ 759 loadsegment(fs, __KERNEL_PERCPU); 760 #endif 761 } 762 763 static const struct cpu_dev *cpu_devs[X86_VENDOR_NUM] = {}; 764 765 static void get_model_name(struct cpuinfo_x86 *c) 766 { 767 unsigned int *v; 768 char *p, *q, *s; 769 770 if (c->extended_cpuid_level < 0x80000004) 771 return; 772 773 v = (unsigned int *)c->x86_model_id; 774 cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]); 775 cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]); 776 cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]); 777 c->x86_model_id[48] = 0; 778 779 /* Trim whitespace */ 780 p = q = s = &c->x86_model_id[0]; 781 782 while (*p == ' ') 783 p++; 784 785 while (*p) { 786 /* Note the last non-whitespace index */ 787 if (!isspace(*p)) 788 s = q; 789 790 *q++ = *p++; 791 } 792 793 *(s + 1) = '\0'; 794 } 795 796 void detect_num_cpu_cores(struct cpuinfo_x86 *c) 797 { 798 unsigned int eax, ebx, ecx, edx; 799 800 c->x86_max_cores = 1; 801 if (!IS_ENABLED(CONFIG_SMP) || c->cpuid_level < 4) 802 return; 803 804 cpuid_count(4, 0, &eax, &ebx, &ecx, &edx); 805 if (eax & 0x1f) 806 c->x86_max_cores = (eax >> 26) + 1; 807 } 808 809 void cpu_detect_cache_sizes(struct cpuinfo_x86 *c) 810 { 811 unsigned int n, dummy, ebx, ecx, edx, l2size; 812 813 n = c->extended_cpuid_level; 814 815 if (n >= 0x80000005) { 816 cpuid(0x80000005, &dummy, &ebx, &ecx, &edx); 817 c->x86_cache_size = (ecx>>24) + (edx>>24); 818 #ifdef CONFIG_X86_64 819 /* On K8 L1 TLB is inclusive, so don't count it */ 820 c->x86_tlbsize = 0; 821 #endif 822 } 823 824 if (n < 0x80000006) /* Some chips just has a large L1. */ 825 return; 826 827 cpuid(0x80000006, &dummy, &ebx, &ecx, &edx); 828 l2size = ecx >> 16; 829 830 #ifdef CONFIG_X86_64 831 c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff); 832 #else 833 /* do processor-specific cache resizing */ 834 if (this_cpu->legacy_cache_size) 835 l2size = this_cpu->legacy_cache_size(c, l2size); 836 837 /* Allow user to override all this if necessary. */ 838 if (cachesize_override != -1) 839 l2size = cachesize_override; 840 841 if (l2size == 0) 842 return; /* Again, no L2 cache is possible */ 843 #endif 844 845 c->x86_cache_size = l2size; 846 } 847 848 u16 __read_mostly tlb_lli_4k[NR_INFO]; 849 u16 __read_mostly tlb_lli_2m[NR_INFO]; 850 u16 __read_mostly tlb_lli_4m[NR_INFO]; 851 u16 __read_mostly tlb_lld_4k[NR_INFO]; 852 u16 __read_mostly tlb_lld_2m[NR_INFO]; 853 u16 __read_mostly tlb_lld_4m[NR_INFO]; 854 u16 __read_mostly tlb_lld_1g[NR_INFO]; 855 856 static void cpu_detect_tlb(struct cpuinfo_x86 *c) 857 { 858 if (this_cpu->c_detect_tlb) 859 this_cpu->c_detect_tlb(c); 860 861 pr_info("Last level iTLB entries: 4KB %d, 2MB %d, 4MB %d\n", 862 tlb_lli_4k[ENTRIES], tlb_lli_2m[ENTRIES], 863 tlb_lli_4m[ENTRIES]); 864 865 pr_info("Last level dTLB entries: 4KB %d, 2MB %d, 4MB %d, 1GB %d\n", 866 tlb_lld_4k[ENTRIES], tlb_lld_2m[ENTRIES], 867 tlb_lld_4m[ENTRIES], tlb_lld_1g[ENTRIES]); 868 } 869 870 int detect_ht_early(struct cpuinfo_x86 *c) 871 { 872 #ifdef CONFIG_SMP 873 u32 eax, ebx, ecx, edx; 874 875 if (!cpu_has(c, X86_FEATURE_HT)) 876 return -1; 877 878 if (cpu_has(c, X86_FEATURE_CMP_LEGACY)) 879 return -1; 880 881 if (cpu_has(c, X86_FEATURE_XTOPOLOGY)) 882 return -1; 883 884 cpuid(1, &eax, &ebx, &ecx, &edx); 885 886 smp_num_siblings = (ebx & 0xff0000) >> 16; 887 if (smp_num_siblings == 1) 888 pr_info_once("CPU0: Hyper-Threading is disabled\n"); 889 #endif 890 return 0; 891 } 892 893 void detect_ht(struct cpuinfo_x86 *c) 894 { 895 #ifdef CONFIG_SMP 896 int index_msb, core_bits; 897 898 if (detect_ht_early(c) < 0) 899 return; 900 901 index_msb = get_count_order(smp_num_siblings); 902 c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb); 903 904 smp_num_siblings = smp_num_siblings / c->x86_max_cores; 905 906 index_msb = get_count_order(smp_num_siblings); 907 908 core_bits = get_count_order(c->x86_max_cores); 909 910 c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, index_msb) & 911 ((1 << core_bits) - 1); 912 #endif 913 } 914 915 static void get_cpu_vendor(struct cpuinfo_x86 *c) 916 { 917 char *v = c->x86_vendor_id; 918 int i; 919 920 for (i = 0; i < X86_VENDOR_NUM; i++) { 921 if (!cpu_devs[i]) 922 break; 923 924 if (!strcmp(v, cpu_devs[i]->c_ident[0]) || 925 (cpu_devs[i]->c_ident[1] && 926 !strcmp(v, cpu_devs[i]->c_ident[1]))) { 927 928 this_cpu = cpu_devs[i]; 929 c->x86_vendor = this_cpu->c_x86_vendor; 930 return; 931 } 932 } 933 934 pr_err_once("CPU: vendor_id '%s' unknown, using generic init.\n" \ 935 "CPU: Your system may be unstable.\n", v); 936 937 c->x86_vendor = X86_VENDOR_UNKNOWN; 938 this_cpu = &default_cpu; 939 } 940 941 void cpu_detect(struct cpuinfo_x86 *c) 942 { 943 /* Get vendor name */ 944 cpuid(0x00000000, (unsigned int *)&c->cpuid_level, 945 (unsigned int *)&c->x86_vendor_id[0], 946 (unsigned int *)&c->x86_vendor_id[8], 947 (unsigned int *)&c->x86_vendor_id[4]); 948 949 c->x86 = 4; 950 /* Intel-defined flags: level 0x00000001 */ 951 if (c->cpuid_level >= 0x00000001) { 952 u32 junk, tfms, cap0, misc; 953 954 cpuid(0x00000001, &tfms, &misc, &junk, &cap0); 955 c->x86 = x86_family(tfms); 956 c->x86_model = x86_model(tfms); 957 c->x86_stepping = x86_stepping(tfms); 958 959 if (cap0 & (1<<19)) { 960 c->x86_clflush_size = ((misc >> 8) & 0xff) * 8; 961 c->x86_cache_alignment = c->x86_clflush_size; 962 } 963 } 964 } 965 966 static void apply_forced_caps(struct cpuinfo_x86 *c) 967 { 968 int i; 969 970 for (i = 0; i < NCAPINTS + NBUGINTS; i++) { 971 c->x86_capability[i] &= ~cpu_caps_cleared[i]; 972 c->x86_capability[i] |= cpu_caps_set[i]; 973 } 974 } 975 976 static void init_speculation_control(struct cpuinfo_x86 *c) 977 { 978 /* 979 * The Intel SPEC_CTRL CPUID bit implies IBRS and IBPB support, 980 * and they also have a different bit for STIBP support. Also, 981 * a hypervisor might have set the individual AMD bits even on 982 * Intel CPUs, for finer-grained selection of what's available. 983 */ 984 if (cpu_has(c, X86_FEATURE_SPEC_CTRL)) { 985 set_cpu_cap(c, X86_FEATURE_IBRS); 986 set_cpu_cap(c, X86_FEATURE_IBPB); 987 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 988 } 989 990 if (cpu_has(c, X86_FEATURE_INTEL_STIBP)) 991 set_cpu_cap(c, X86_FEATURE_STIBP); 992 993 if (cpu_has(c, X86_FEATURE_SPEC_CTRL_SSBD) || 994 cpu_has(c, X86_FEATURE_VIRT_SSBD)) 995 set_cpu_cap(c, X86_FEATURE_SSBD); 996 997 if (cpu_has(c, X86_FEATURE_AMD_IBRS)) { 998 set_cpu_cap(c, X86_FEATURE_IBRS); 999 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 1000 } 1001 1002 if (cpu_has(c, X86_FEATURE_AMD_IBPB)) 1003 set_cpu_cap(c, X86_FEATURE_IBPB); 1004 1005 if (cpu_has(c, X86_FEATURE_AMD_STIBP)) { 1006 set_cpu_cap(c, X86_FEATURE_STIBP); 1007 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 1008 } 1009 1010 if (cpu_has(c, X86_FEATURE_AMD_SSBD)) { 1011 set_cpu_cap(c, X86_FEATURE_SSBD); 1012 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 1013 clear_cpu_cap(c, X86_FEATURE_VIRT_SSBD); 1014 } 1015 } 1016 1017 void get_cpu_cap(struct cpuinfo_x86 *c) 1018 { 1019 u32 eax, ebx, ecx, edx; 1020 1021 /* Intel-defined flags: level 0x00000001 */ 1022 if (c->cpuid_level >= 0x00000001) { 1023 cpuid(0x00000001, &eax, &ebx, &ecx, &edx); 1024 1025 c->x86_capability[CPUID_1_ECX] = ecx; 1026 c->x86_capability[CPUID_1_EDX] = edx; 1027 } 1028 1029 /* Thermal and Power Management Leaf: level 0x00000006 (eax) */ 1030 if (c->cpuid_level >= 0x00000006) 1031 c->x86_capability[CPUID_6_EAX] = cpuid_eax(0x00000006); 1032 1033 /* Additional Intel-defined flags: level 0x00000007 */ 1034 if (c->cpuid_level >= 0x00000007) { 1035 cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx); 1036 c->x86_capability[CPUID_7_0_EBX] = ebx; 1037 c->x86_capability[CPUID_7_ECX] = ecx; 1038 c->x86_capability[CPUID_7_EDX] = edx; 1039 1040 /* Check valid sub-leaf index before accessing it */ 1041 if (eax >= 1) { 1042 cpuid_count(0x00000007, 1, &eax, &ebx, &ecx, &edx); 1043 c->x86_capability[CPUID_7_1_EAX] = eax; 1044 } 1045 } 1046 1047 /* Extended state features: level 0x0000000d */ 1048 if (c->cpuid_level >= 0x0000000d) { 1049 cpuid_count(0x0000000d, 1, &eax, &ebx, &ecx, &edx); 1050 1051 c->x86_capability[CPUID_D_1_EAX] = eax; 1052 } 1053 1054 /* AMD-defined flags: level 0x80000001 */ 1055 eax = cpuid_eax(0x80000000); 1056 c->extended_cpuid_level = eax; 1057 1058 if ((eax & 0xffff0000) == 0x80000000) { 1059 if (eax >= 0x80000001) { 1060 cpuid(0x80000001, &eax, &ebx, &ecx, &edx); 1061 1062 c->x86_capability[CPUID_8000_0001_ECX] = ecx; 1063 c->x86_capability[CPUID_8000_0001_EDX] = edx; 1064 } 1065 } 1066 1067 if (c->extended_cpuid_level >= 0x80000007) { 1068 cpuid(0x80000007, &eax, &ebx, &ecx, &edx); 1069 1070 c->x86_capability[CPUID_8000_0007_EBX] = ebx; 1071 c->x86_power = edx; 1072 } 1073 1074 if (c->extended_cpuid_level >= 0x80000008) { 1075 cpuid(0x80000008, &eax, &ebx, &ecx, &edx); 1076 c->x86_capability[CPUID_8000_0008_EBX] = ebx; 1077 } 1078 1079 if (c->extended_cpuid_level >= 0x8000000a) 1080 c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a); 1081 1082 if (c->extended_cpuid_level >= 0x8000001f) 1083 c->x86_capability[CPUID_8000_001F_EAX] = cpuid_eax(0x8000001f); 1084 1085 if (c->extended_cpuid_level >= 0x80000021) 1086 c->x86_capability[CPUID_8000_0021_EAX] = cpuid_eax(0x80000021); 1087 1088 init_scattered_cpuid_features(c); 1089 init_speculation_control(c); 1090 1091 /* 1092 * Clear/Set all flags overridden by options, after probe. 1093 * This needs to happen each time we re-probe, which may happen 1094 * several times during CPU initialization. 1095 */ 1096 apply_forced_caps(c); 1097 } 1098 1099 void get_cpu_address_sizes(struct cpuinfo_x86 *c) 1100 { 1101 u32 eax, ebx, ecx, edx; 1102 1103 if (c->extended_cpuid_level >= 0x80000008) { 1104 cpuid(0x80000008, &eax, &ebx, &ecx, &edx); 1105 1106 c->x86_virt_bits = (eax >> 8) & 0xff; 1107 c->x86_phys_bits = eax & 0xff; 1108 } 1109 #ifdef CONFIG_X86_32 1110 else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36)) 1111 c->x86_phys_bits = 36; 1112 #endif 1113 c->x86_cache_bits = c->x86_phys_bits; 1114 } 1115 1116 static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c) 1117 { 1118 #ifdef CONFIG_X86_32 1119 int i; 1120 1121 /* 1122 * First of all, decide if this is a 486 or higher 1123 * It's a 486 if we can modify the AC flag 1124 */ 1125 if (flag_is_changeable_p(X86_EFLAGS_AC)) 1126 c->x86 = 4; 1127 else 1128 c->x86 = 3; 1129 1130 for (i = 0; i < X86_VENDOR_NUM; i++) 1131 if (cpu_devs[i] && cpu_devs[i]->c_identify) { 1132 c->x86_vendor_id[0] = 0; 1133 cpu_devs[i]->c_identify(c); 1134 if (c->x86_vendor_id[0]) { 1135 get_cpu_vendor(c); 1136 break; 1137 } 1138 } 1139 #endif 1140 } 1141 1142 #define NO_SPECULATION BIT(0) 1143 #define NO_MELTDOWN BIT(1) 1144 #define NO_SSB BIT(2) 1145 #define NO_L1TF BIT(3) 1146 #define NO_MDS BIT(4) 1147 #define MSBDS_ONLY BIT(5) 1148 #define NO_SWAPGS BIT(6) 1149 #define NO_ITLB_MULTIHIT BIT(7) 1150 #define NO_SPECTRE_V2 BIT(8) 1151 #define NO_MMIO BIT(9) 1152 #define NO_EIBRS_PBRSB BIT(10) 1153 1154 #define VULNWL(vendor, family, model, whitelist) \ 1155 X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, whitelist) 1156 1157 #define VULNWL_INTEL(model, whitelist) \ 1158 VULNWL(INTEL, 6, INTEL_FAM6_##model, whitelist) 1159 1160 #define VULNWL_AMD(family, whitelist) \ 1161 VULNWL(AMD, family, X86_MODEL_ANY, whitelist) 1162 1163 #define VULNWL_HYGON(family, whitelist) \ 1164 VULNWL(HYGON, family, X86_MODEL_ANY, whitelist) 1165 1166 static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = { 1167 VULNWL(ANY, 4, X86_MODEL_ANY, NO_SPECULATION), 1168 VULNWL(CENTAUR, 5, X86_MODEL_ANY, NO_SPECULATION), 1169 VULNWL(INTEL, 5, X86_MODEL_ANY, NO_SPECULATION), 1170 VULNWL(NSC, 5, X86_MODEL_ANY, NO_SPECULATION), 1171 VULNWL(VORTEX, 5, X86_MODEL_ANY, NO_SPECULATION), 1172 VULNWL(VORTEX, 6, X86_MODEL_ANY, NO_SPECULATION), 1173 1174 /* Intel Family 6 */ 1175 VULNWL_INTEL(TIGERLAKE, NO_MMIO), 1176 VULNWL_INTEL(TIGERLAKE_L, NO_MMIO), 1177 VULNWL_INTEL(ALDERLAKE, NO_MMIO), 1178 VULNWL_INTEL(ALDERLAKE_L, NO_MMIO), 1179 1180 VULNWL_INTEL(ATOM_SALTWELL, NO_SPECULATION | NO_ITLB_MULTIHIT), 1181 VULNWL_INTEL(ATOM_SALTWELL_TABLET, NO_SPECULATION | NO_ITLB_MULTIHIT), 1182 VULNWL_INTEL(ATOM_SALTWELL_MID, NO_SPECULATION | NO_ITLB_MULTIHIT), 1183 VULNWL_INTEL(ATOM_BONNELL, NO_SPECULATION | NO_ITLB_MULTIHIT), 1184 VULNWL_INTEL(ATOM_BONNELL_MID, NO_SPECULATION | NO_ITLB_MULTIHIT), 1185 1186 VULNWL_INTEL(ATOM_SILVERMONT, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1187 VULNWL_INTEL(ATOM_SILVERMONT_D, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1188 VULNWL_INTEL(ATOM_SILVERMONT_MID, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1189 VULNWL_INTEL(ATOM_AIRMONT, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1190 VULNWL_INTEL(XEON_PHI_KNL, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1191 VULNWL_INTEL(XEON_PHI_KNM, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1192 1193 VULNWL_INTEL(CORE_YONAH, NO_SSB), 1194 1195 VULNWL_INTEL(ATOM_AIRMONT_MID, NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1196 VULNWL_INTEL(ATOM_AIRMONT_NP, NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT), 1197 1198 VULNWL_INTEL(ATOM_GOLDMONT, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1199 VULNWL_INTEL(ATOM_GOLDMONT_D, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1200 VULNWL_INTEL(ATOM_GOLDMONT_PLUS, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_EIBRS_PBRSB), 1201 1202 /* 1203 * Technically, swapgs isn't serializing on AMD (despite it previously 1204 * being documented as such in the APM). But according to AMD, %gs is 1205 * updated non-speculatively, and the issuing of %gs-relative memory 1206 * operands will be blocked until the %gs update completes, which is 1207 * good enough for our purposes. 1208 */ 1209 1210 VULNWL_INTEL(ATOM_TREMONT, NO_EIBRS_PBRSB), 1211 VULNWL_INTEL(ATOM_TREMONT_L, NO_EIBRS_PBRSB), 1212 VULNWL_INTEL(ATOM_TREMONT_D, NO_ITLB_MULTIHIT | NO_EIBRS_PBRSB), 1213 1214 /* AMD Family 0xf - 0x12 */ 1215 VULNWL_AMD(0x0f, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1216 VULNWL_AMD(0x10, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1217 VULNWL_AMD(0x11, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1218 VULNWL_AMD(0x12, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1219 1220 /* FAMILY_ANY must be last, otherwise 0x0f - 0x12 matches won't work */ 1221 VULNWL_AMD(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_EIBRS_PBRSB), 1222 VULNWL_HYGON(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_EIBRS_PBRSB), 1223 1224 /* Zhaoxin Family 7 */ 1225 VULNWL(CENTAUR, 7, X86_MODEL_ANY, NO_SPECTRE_V2 | NO_SWAPGS | NO_MMIO), 1226 VULNWL(ZHAOXIN, 7, X86_MODEL_ANY, NO_SPECTRE_V2 | NO_SWAPGS | NO_MMIO), 1227 {} 1228 }; 1229 1230 #define VULNBL(vendor, family, model, blacklist) \ 1231 X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, blacklist) 1232 1233 #define VULNBL_INTEL_STEPPINGS(model, steppings, issues) \ 1234 X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(INTEL, 6, \ 1235 INTEL_FAM6_##model, steppings, \ 1236 X86_FEATURE_ANY, issues) 1237 1238 #define VULNBL_AMD(family, blacklist) \ 1239 VULNBL(AMD, family, X86_MODEL_ANY, blacklist) 1240 1241 #define VULNBL_HYGON(family, blacklist) \ 1242 VULNBL(HYGON, family, X86_MODEL_ANY, blacklist) 1243 1244 #define SRBDS BIT(0) 1245 /* CPU is affected by X86_BUG_MMIO_STALE_DATA */ 1246 #define MMIO BIT(1) 1247 /* CPU is affected by Shared Buffers Data Sampling (SBDS), a variant of X86_BUG_MMIO_STALE_DATA */ 1248 #define MMIO_SBDS BIT(2) 1249 /* CPU is affected by RETbleed, speculating where you would not expect it */ 1250 #define RETBLEED BIT(3) 1251 /* CPU is affected by SMT (cross-thread) return predictions */ 1252 #define SMT_RSB BIT(4) 1253 1254 static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = { 1255 VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS), 1256 VULNBL_INTEL_STEPPINGS(HASWELL, X86_STEPPING_ANY, SRBDS), 1257 VULNBL_INTEL_STEPPINGS(HASWELL_L, X86_STEPPING_ANY, SRBDS), 1258 VULNBL_INTEL_STEPPINGS(HASWELL_G, X86_STEPPING_ANY, SRBDS), 1259 VULNBL_INTEL_STEPPINGS(HASWELL_X, X86_STEPPING_ANY, MMIO), 1260 VULNBL_INTEL_STEPPINGS(BROADWELL_D, X86_STEPPING_ANY, MMIO), 1261 VULNBL_INTEL_STEPPINGS(BROADWELL_G, X86_STEPPING_ANY, SRBDS), 1262 VULNBL_INTEL_STEPPINGS(BROADWELL_X, X86_STEPPING_ANY, MMIO), 1263 VULNBL_INTEL_STEPPINGS(BROADWELL, X86_STEPPING_ANY, SRBDS), 1264 VULNBL_INTEL_STEPPINGS(SKYLAKE_L, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED), 1265 VULNBL_INTEL_STEPPINGS(SKYLAKE_X, X86_STEPPING_ANY, MMIO | RETBLEED), 1266 VULNBL_INTEL_STEPPINGS(SKYLAKE, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED), 1267 VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED), 1268 VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED), 1269 VULNBL_INTEL_STEPPINGS(CANNONLAKE_L, X86_STEPPING_ANY, RETBLEED), 1270 VULNBL_INTEL_STEPPINGS(ICELAKE_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED), 1271 VULNBL_INTEL_STEPPINGS(ICELAKE_D, X86_STEPPING_ANY, MMIO), 1272 VULNBL_INTEL_STEPPINGS(ICELAKE_X, X86_STEPPING_ANY, MMIO), 1273 VULNBL_INTEL_STEPPINGS(COMETLAKE, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED), 1274 VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x0), MMIO | RETBLEED), 1275 VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED), 1276 VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED), 1277 VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPING_ANY, MMIO | RETBLEED), 1278 VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPING_ANY, MMIO | MMIO_SBDS), 1279 VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_D, X86_STEPPING_ANY, MMIO), 1280 VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS), 1281 1282 VULNBL_AMD(0x15, RETBLEED), 1283 VULNBL_AMD(0x16, RETBLEED), 1284 VULNBL_AMD(0x17, RETBLEED | SMT_RSB), 1285 VULNBL_HYGON(0x18, RETBLEED | SMT_RSB), 1286 {} 1287 }; 1288 1289 static bool __init cpu_matches(const struct x86_cpu_id *table, unsigned long which) 1290 { 1291 const struct x86_cpu_id *m = x86_match_cpu(table); 1292 1293 return m && !!(m->driver_data & which); 1294 } 1295 1296 u64 x86_read_arch_cap_msr(void) 1297 { 1298 u64 ia32_cap = 0; 1299 1300 if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES)) 1301 rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap); 1302 1303 return ia32_cap; 1304 } 1305 1306 static bool arch_cap_mmio_immune(u64 ia32_cap) 1307 { 1308 return (ia32_cap & ARCH_CAP_FBSDP_NO && 1309 ia32_cap & ARCH_CAP_PSDP_NO && 1310 ia32_cap & ARCH_CAP_SBDR_SSDP_NO); 1311 } 1312 1313 static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) 1314 { 1315 u64 ia32_cap = x86_read_arch_cap_msr(); 1316 1317 /* Set ITLB_MULTIHIT bug if cpu is not in the whitelist and not mitigated */ 1318 if (!cpu_matches(cpu_vuln_whitelist, NO_ITLB_MULTIHIT) && 1319 !(ia32_cap & ARCH_CAP_PSCHANGE_MC_NO)) 1320 setup_force_cpu_bug(X86_BUG_ITLB_MULTIHIT); 1321 1322 if (cpu_matches(cpu_vuln_whitelist, NO_SPECULATION)) 1323 return; 1324 1325 setup_force_cpu_bug(X86_BUG_SPECTRE_V1); 1326 1327 if (!cpu_matches(cpu_vuln_whitelist, NO_SPECTRE_V2)) 1328 setup_force_cpu_bug(X86_BUG_SPECTRE_V2); 1329 1330 if (!cpu_matches(cpu_vuln_whitelist, NO_SSB) && 1331 !(ia32_cap & ARCH_CAP_SSB_NO) && 1332 !cpu_has(c, X86_FEATURE_AMD_SSB_NO)) 1333 setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS); 1334 1335 /* 1336 * AMD's AutoIBRS is equivalent to Intel's eIBRS - use the Intel feature 1337 * flag and protect from vendor-specific bugs via the whitelist. 1338 */ 1339 if ((ia32_cap & ARCH_CAP_IBRS_ALL) || cpu_has(c, X86_FEATURE_AUTOIBRS)) { 1340 setup_force_cpu_cap(X86_FEATURE_IBRS_ENHANCED); 1341 if (!cpu_matches(cpu_vuln_whitelist, NO_EIBRS_PBRSB) && 1342 !(ia32_cap & ARCH_CAP_PBRSB_NO)) 1343 setup_force_cpu_bug(X86_BUG_EIBRS_PBRSB); 1344 } 1345 1346 if (!cpu_matches(cpu_vuln_whitelist, NO_MDS) && 1347 !(ia32_cap & ARCH_CAP_MDS_NO)) { 1348 setup_force_cpu_bug(X86_BUG_MDS); 1349 if (cpu_matches(cpu_vuln_whitelist, MSBDS_ONLY)) 1350 setup_force_cpu_bug(X86_BUG_MSBDS_ONLY); 1351 } 1352 1353 if (!cpu_matches(cpu_vuln_whitelist, NO_SWAPGS)) 1354 setup_force_cpu_bug(X86_BUG_SWAPGS); 1355 1356 /* 1357 * When the CPU is not mitigated for TAA (TAA_NO=0) set TAA bug when: 1358 * - TSX is supported or 1359 * - TSX_CTRL is present 1360 * 1361 * TSX_CTRL check is needed for cases when TSX could be disabled before 1362 * the kernel boot e.g. kexec. 1363 * TSX_CTRL check alone is not sufficient for cases when the microcode 1364 * update is not present or running as guest that don't get TSX_CTRL. 1365 */ 1366 if (!(ia32_cap & ARCH_CAP_TAA_NO) && 1367 (cpu_has(c, X86_FEATURE_RTM) || 1368 (ia32_cap & ARCH_CAP_TSX_CTRL_MSR))) 1369 setup_force_cpu_bug(X86_BUG_TAA); 1370 1371 /* 1372 * SRBDS affects CPUs which support RDRAND or RDSEED and are listed 1373 * in the vulnerability blacklist. 1374 * 1375 * Some of the implications and mitigation of Shared Buffers Data 1376 * Sampling (SBDS) are similar to SRBDS. Give SBDS same treatment as 1377 * SRBDS. 1378 */ 1379 if ((cpu_has(c, X86_FEATURE_RDRAND) || 1380 cpu_has(c, X86_FEATURE_RDSEED)) && 1381 cpu_matches(cpu_vuln_blacklist, SRBDS | MMIO_SBDS)) 1382 setup_force_cpu_bug(X86_BUG_SRBDS); 1383 1384 /* 1385 * Processor MMIO Stale Data bug enumeration 1386 * 1387 * Affected CPU list is generally enough to enumerate the vulnerability, 1388 * but for virtualization case check for ARCH_CAP MSR bits also, VMM may 1389 * not want the guest to enumerate the bug. 1390 * 1391 * Set X86_BUG_MMIO_UNKNOWN for CPUs that are neither in the blacklist, 1392 * nor in the whitelist and also don't enumerate MSR ARCH_CAP MMIO bits. 1393 */ 1394 if (!arch_cap_mmio_immune(ia32_cap)) { 1395 if (cpu_matches(cpu_vuln_blacklist, MMIO)) 1396 setup_force_cpu_bug(X86_BUG_MMIO_STALE_DATA); 1397 else if (!cpu_matches(cpu_vuln_whitelist, NO_MMIO)) 1398 setup_force_cpu_bug(X86_BUG_MMIO_UNKNOWN); 1399 } 1400 1401 if (!cpu_has(c, X86_FEATURE_BTC_NO)) { 1402 if (cpu_matches(cpu_vuln_blacklist, RETBLEED) || (ia32_cap & ARCH_CAP_RSBA)) 1403 setup_force_cpu_bug(X86_BUG_RETBLEED); 1404 } 1405 1406 if (cpu_matches(cpu_vuln_blacklist, SMT_RSB)) 1407 setup_force_cpu_bug(X86_BUG_SMT_RSB); 1408 1409 if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN)) 1410 return; 1411 1412 /* Rogue Data Cache Load? No! */ 1413 if (ia32_cap & ARCH_CAP_RDCL_NO) 1414 return; 1415 1416 setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN); 1417 1418 if (cpu_matches(cpu_vuln_whitelist, NO_L1TF)) 1419 return; 1420 1421 setup_force_cpu_bug(X86_BUG_L1TF); 1422 } 1423 1424 /* 1425 * The NOPL instruction is supposed to exist on all CPUs of family >= 6; 1426 * unfortunately, that's not true in practice because of early VIA 1427 * chips and (more importantly) broken virtualizers that are not easy 1428 * to detect. In the latter case it doesn't even *fail* reliably, so 1429 * probing for it doesn't even work. Disable it completely on 32-bit 1430 * unless we can find a reliable way to detect all the broken cases. 1431 * Enable it explicitly on 64-bit for non-constant inputs of cpu_has(). 1432 */ 1433 static void detect_nopl(void) 1434 { 1435 #ifdef CONFIG_X86_32 1436 setup_clear_cpu_cap(X86_FEATURE_NOPL); 1437 #else 1438 setup_force_cpu_cap(X86_FEATURE_NOPL); 1439 #endif 1440 } 1441 1442 /* 1443 * We parse cpu parameters early because fpu__init_system() is executed 1444 * before parse_early_param(). 1445 */ 1446 static void __init cpu_parse_early_param(void) 1447 { 1448 char arg[128]; 1449 char *argptr = arg, *opt; 1450 int arglen, taint = 0; 1451 1452 #ifdef CONFIG_X86_32 1453 if (cmdline_find_option_bool(boot_command_line, "no387")) 1454 #ifdef CONFIG_MATH_EMULATION 1455 setup_clear_cpu_cap(X86_FEATURE_FPU); 1456 #else 1457 pr_err("Option 'no387' required CONFIG_MATH_EMULATION enabled.\n"); 1458 #endif 1459 1460 if (cmdline_find_option_bool(boot_command_line, "nofxsr")) 1461 setup_clear_cpu_cap(X86_FEATURE_FXSR); 1462 #endif 1463 1464 if (cmdline_find_option_bool(boot_command_line, "noxsave")) 1465 setup_clear_cpu_cap(X86_FEATURE_XSAVE); 1466 1467 if (cmdline_find_option_bool(boot_command_line, "noxsaveopt")) 1468 setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT); 1469 1470 if (cmdline_find_option_bool(boot_command_line, "noxsaves")) 1471 setup_clear_cpu_cap(X86_FEATURE_XSAVES); 1472 1473 arglen = cmdline_find_option(boot_command_line, "clearcpuid", arg, sizeof(arg)); 1474 if (arglen <= 0) 1475 return; 1476 1477 pr_info("Clearing CPUID bits:"); 1478 1479 while (argptr) { 1480 bool found __maybe_unused = false; 1481 unsigned int bit; 1482 1483 opt = strsep(&argptr, ","); 1484 1485 /* 1486 * Handle naked numbers first for feature flags which don't 1487 * have names. 1488 */ 1489 if (!kstrtouint(opt, 10, &bit)) { 1490 if (bit < NCAPINTS * 32) { 1491 1492 /* empty-string, i.e., ""-defined feature flags */ 1493 if (!x86_cap_flags[bit]) 1494 pr_cont(" " X86_CAP_FMT_NUM, x86_cap_flag_num(bit)); 1495 else 1496 pr_cont(" " X86_CAP_FMT, x86_cap_flag(bit)); 1497 1498 setup_clear_cpu_cap(bit); 1499 taint++; 1500 } 1501 /* 1502 * The assumption is that there are no feature names with only 1503 * numbers in the name thus go to the next argument. 1504 */ 1505 continue; 1506 } 1507 1508 for (bit = 0; bit < 32 * NCAPINTS; bit++) { 1509 if (!x86_cap_flag(bit)) 1510 continue; 1511 1512 if (strcmp(x86_cap_flag(bit), opt)) 1513 continue; 1514 1515 pr_cont(" %s", opt); 1516 setup_clear_cpu_cap(bit); 1517 taint++; 1518 found = true; 1519 break; 1520 } 1521 1522 if (!found) 1523 pr_cont(" (unknown: %s)", opt); 1524 } 1525 pr_cont("\n"); 1526 1527 if (taint) 1528 add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); 1529 } 1530 1531 /* 1532 * Do minimum CPU detection early. 1533 * Fields really needed: vendor, cpuid_level, family, model, mask, 1534 * cache alignment. 1535 * The others are not touched to avoid unwanted side effects. 1536 * 1537 * WARNING: this function is only called on the boot CPU. Don't add code 1538 * here that is supposed to run on all CPUs. 1539 */ 1540 static void __init early_identify_cpu(struct cpuinfo_x86 *c) 1541 { 1542 #ifdef CONFIG_X86_64 1543 c->x86_clflush_size = 64; 1544 c->x86_phys_bits = 36; 1545 c->x86_virt_bits = 48; 1546 #else 1547 c->x86_clflush_size = 32; 1548 c->x86_phys_bits = 32; 1549 c->x86_virt_bits = 32; 1550 #endif 1551 c->x86_cache_alignment = c->x86_clflush_size; 1552 1553 memset(&c->x86_capability, 0, sizeof(c->x86_capability)); 1554 c->extended_cpuid_level = 0; 1555 1556 if (!have_cpuid_p()) 1557 identify_cpu_without_cpuid(c); 1558 1559 /* cyrix could have cpuid enabled via c_identify()*/ 1560 if (have_cpuid_p()) { 1561 cpu_detect(c); 1562 get_cpu_vendor(c); 1563 get_cpu_cap(c); 1564 get_cpu_address_sizes(c); 1565 setup_force_cpu_cap(X86_FEATURE_CPUID); 1566 cpu_parse_early_param(); 1567 1568 if (this_cpu->c_early_init) 1569 this_cpu->c_early_init(c); 1570 1571 c->cpu_index = 0; 1572 filter_cpuid_features(c, false); 1573 1574 if (this_cpu->c_bsp_init) 1575 this_cpu->c_bsp_init(c); 1576 } else { 1577 setup_clear_cpu_cap(X86_FEATURE_CPUID); 1578 } 1579 1580 setup_force_cpu_cap(X86_FEATURE_ALWAYS); 1581 1582 cpu_set_bug_bits(c); 1583 1584 sld_setup(c); 1585 1586 #ifdef CONFIG_X86_32 1587 /* 1588 * Regardless of whether PCID is enumerated, the SDM says 1589 * that it can't be enabled in 32-bit mode. 1590 */ 1591 setup_clear_cpu_cap(X86_FEATURE_PCID); 1592 #endif 1593 1594 /* 1595 * Later in the boot process pgtable_l5_enabled() relies on 1596 * cpu_feature_enabled(X86_FEATURE_LA57). If 5-level paging is not 1597 * enabled by this point we need to clear the feature bit to avoid 1598 * false-positives at the later stage. 1599 * 1600 * pgtable_l5_enabled() can be false here for several reasons: 1601 * - 5-level paging is disabled compile-time; 1602 * - it's 32-bit kernel; 1603 * - machine doesn't support 5-level paging; 1604 * - user specified 'no5lvl' in kernel command line. 1605 */ 1606 if (!pgtable_l5_enabled()) 1607 setup_clear_cpu_cap(X86_FEATURE_LA57); 1608 1609 detect_nopl(); 1610 } 1611 1612 void __init early_cpu_init(void) 1613 { 1614 const struct cpu_dev *const *cdev; 1615 int count = 0; 1616 1617 #ifdef CONFIG_PROCESSOR_SELECT 1618 pr_info("KERNEL supported cpus:\n"); 1619 #endif 1620 1621 for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) { 1622 const struct cpu_dev *cpudev = *cdev; 1623 1624 if (count >= X86_VENDOR_NUM) 1625 break; 1626 cpu_devs[count] = cpudev; 1627 count++; 1628 1629 #ifdef CONFIG_PROCESSOR_SELECT 1630 { 1631 unsigned int j; 1632 1633 for (j = 0; j < 2; j++) { 1634 if (!cpudev->c_ident[j]) 1635 continue; 1636 pr_info(" %s %s\n", cpudev->c_vendor, 1637 cpudev->c_ident[j]); 1638 } 1639 } 1640 #endif 1641 } 1642 early_identify_cpu(&boot_cpu_data); 1643 } 1644 1645 static bool detect_null_seg_behavior(void) 1646 { 1647 /* 1648 * Empirically, writing zero to a segment selector on AMD does 1649 * not clear the base, whereas writing zero to a segment 1650 * selector on Intel does clear the base. Intel's behavior 1651 * allows slightly faster context switches in the common case 1652 * where GS is unused by the prev and next threads. 1653 * 1654 * Since neither vendor documents this anywhere that I can see, 1655 * detect it directly instead of hard-coding the choice by 1656 * vendor. 1657 * 1658 * I've designated AMD's behavior as the "bug" because it's 1659 * counterintuitive and less friendly. 1660 */ 1661 1662 unsigned long old_base, tmp; 1663 rdmsrl(MSR_FS_BASE, old_base); 1664 wrmsrl(MSR_FS_BASE, 1); 1665 loadsegment(fs, 0); 1666 rdmsrl(MSR_FS_BASE, tmp); 1667 wrmsrl(MSR_FS_BASE, old_base); 1668 return tmp == 0; 1669 } 1670 1671 void check_null_seg_clears_base(struct cpuinfo_x86 *c) 1672 { 1673 /* BUG_NULL_SEG is only relevant with 64bit userspace */ 1674 if (!IS_ENABLED(CONFIG_X86_64)) 1675 return; 1676 1677 if (cpu_has(c, X86_FEATURE_NULL_SEL_CLR_BASE)) 1678 return; 1679 1680 /* 1681 * CPUID bit above wasn't set. If this kernel is still running 1682 * as a HV guest, then the HV has decided not to advertize 1683 * that CPUID bit for whatever reason. For example, one 1684 * member of the migration pool might be vulnerable. Which 1685 * means, the bug is present: set the BUG flag and return. 1686 */ 1687 if (cpu_has(c, X86_FEATURE_HYPERVISOR)) { 1688 set_cpu_bug(c, X86_BUG_NULL_SEG); 1689 return; 1690 } 1691 1692 /* 1693 * Zen2 CPUs also have this behaviour, but no CPUID bit. 1694 * 0x18 is the respective family for Hygon. 1695 */ 1696 if ((c->x86 == 0x17 || c->x86 == 0x18) && 1697 detect_null_seg_behavior()) 1698 return; 1699 1700 /* All the remaining ones are affected */ 1701 set_cpu_bug(c, X86_BUG_NULL_SEG); 1702 } 1703 1704 static void generic_identify(struct cpuinfo_x86 *c) 1705 { 1706 c->extended_cpuid_level = 0; 1707 1708 if (!have_cpuid_p()) 1709 identify_cpu_without_cpuid(c); 1710 1711 /* cyrix could have cpuid enabled via c_identify()*/ 1712 if (!have_cpuid_p()) 1713 return; 1714 1715 cpu_detect(c); 1716 1717 get_cpu_vendor(c); 1718 1719 get_cpu_cap(c); 1720 1721 get_cpu_address_sizes(c); 1722 1723 if (c->cpuid_level >= 0x00000001) { 1724 c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xFF; 1725 #ifdef CONFIG_X86_32 1726 # ifdef CONFIG_SMP 1727 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0); 1728 # else 1729 c->apicid = c->initial_apicid; 1730 # endif 1731 #endif 1732 c->phys_proc_id = c->initial_apicid; 1733 } 1734 1735 get_model_name(c); /* Default name */ 1736 1737 /* 1738 * ESPFIX is a strange bug. All real CPUs have it. Paravirt 1739 * systems that run Linux at CPL > 0 may or may not have the 1740 * issue, but, even if they have the issue, there's absolutely 1741 * nothing we can do about it because we can't use the real IRET 1742 * instruction. 1743 * 1744 * NB: For the time being, only 32-bit kernels support 1745 * X86_BUG_ESPFIX as such. 64-bit kernels directly choose 1746 * whether to apply espfix using paravirt hooks. If any 1747 * non-paravirt system ever shows up that does *not* have the 1748 * ESPFIX issue, we can change this. 1749 */ 1750 #ifdef CONFIG_X86_32 1751 set_cpu_bug(c, X86_BUG_ESPFIX); 1752 #endif 1753 } 1754 1755 /* 1756 * Validate that ACPI/mptables have the same information about the 1757 * effective APIC id and update the package map. 1758 */ 1759 static void validate_apic_and_package_id(struct cpuinfo_x86 *c) 1760 { 1761 #ifdef CONFIG_SMP 1762 unsigned int apicid, cpu = smp_processor_id(); 1763 1764 apicid = apic->cpu_present_to_apicid(cpu); 1765 1766 if (apicid != c->apicid) { 1767 pr_err(FW_BUG "CPU%u: APIC id mismatch. Firmware: %x APIC: %x\n", 1768 cpu, apicid, c->initial_apicid); 1769 } 1770 BUG_ON(topology_update_package_map(c->phys_proc_id, cpu)); 1771 BUG_ON(topology_update_die_map(c->cpu_die_id, cpu)); 1772 #else 1773 c->logical_proc_id = 0; 1774 #endif 1775 } 1776 1777 /* 1778 * This does the hard work of actually picking apart the CPU stuff... 1779 */ 1780 static void identify_cpu(struct cpuinfo_x86 *c) 1781 { 1782 int i; 1783 1784 c->loops_per_jiffy = loops_per_jiffy; 1785 c->x86_cache_size = 0; 1786 c->x86_vendor = X86_VENDOR_UNKNOWN; 1787 c->x86_model = c->x86_stepping = 0; /* So far unknown... */ 1788 c->x86_vendor_id[0] = '\0'; /* Unset */ 1789 c->x86_model_id[0] = '\0'; /* Unset */ 1790 c->x86_max_cores = 1; 1791 c->x86_coreid_bits = 0; 1792 c->cu_id = 0xff; 1793 #ifdef CONFIG_X86_64 1794 c->x86_clflush_size = 64; 1795 c->x86_phys_bits = 36; 1796 c->x86_virt_bits = 48; 1797 #else 1798 c->cpuid_level = -1; /* CPUID not detected */ 1799 c->x86_clflush_size = 32; 1800 c->x86_phys_bits = 32; 1801 c->x86_virt_bits = 32; 1802 #endif 1803 c->x86_cache_alignment = c->x86_clflush_size; 1804 memset(&c->x86_capability, 0, sizeof(c->x86_capability)); 1805 #ifdef CONFIG_X86_VMX_FEATURE_NAMES 1806 memset(&c->vmx_capability, 0, sizeof(c->vmx_capability)); 1807 #endif 1808 1809 generic_identify(c); 1810 1811 if (this_cpu->c_identify) 1812 this_cpu->c_identify(c); 1813 1814 /* Clear/Set all flags overridden by options, after probe */ 1815 apply_forced_caps(c); 1816 1817 #ifdef CONFIG_X86_64 1818 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0); 1819 #endif 1820 1821 /* 1822 * Vendor-specific initialization. In this section we 1823 * canonicalize the feature flags, meaning if there are 1824 * features a certain CPU supports which CPUID doesn't 1825 * tell us, CPUID claiming incorrect flags, or other bugs, 1826 * we handle them here. 1827 * 1828 * At the end of this section, c->x86_capability better 1829 * indicate the features this CPU genuinely supports! 1830 */ 1831 if (this_cpu->c_init) 1832 this_cpu->c_init(c); 1833 1834 /* Disable the PN if appropriate */ 1835 squash_the_stupid_serial_number(c); 1836 1837 /* Set up SMEP/SMAP/UMIP */ 1838 setup_smep(c); 1839 setup_smap(c); 1840 setup_umip(c); 1841 1842 /* Enable FSGSBASE instructions if available. */ 1843 if (cpu_has(c, X86_FEATURE_FSGSBASE)) { 1844 cr4_set_bits(X86_CR4_FSGSBASE); 1845 elf_hwcap2 |= HWCAP2_FSGSBASE; 1846 } 1847 1848 /* 1849 * The vendor-specific functions might have changed features. 1850 * Now we do "generic changes." 1851 */ 1852 1853 /* Filter out anything that depends on CPUID levels we don't have */ 1854 filter_cpuid_features(c, true); 1855 1856 /* If the model name is still unset, do table lookup. */ 1857 if (!c->x86_model_id[0]) { 1858 const char *p; 1859 p = table_lookup_model(c); 1860 if (p) 1861 strcpy(c->x86_model_id, p); 1862 else 1863 /* Last resort... */ 1864 sprintf(c->x86_model_id, "%02x/%02x", 1865 c->x86, c->x86_model); 1866 } 1867 1868 #ifdef CONFIG_X86_64 1869 detect_ht(c); 1870 #endif 1871 1872 x86_init_rdrand(c); 1873 setup_pku(c); 1874 setup_cet(c); 1875 1876 /* 1877 * Clear/Set all flags overridden by options, need do it 1878 * before following smp all cpus cap AND. 1879 */ 1880 apply_forced_caps(c); 1881 1882 /* 1883 * On SMP, boot_cpu_data holds the common feature set between 1884 * all CPUs; so make sure that we indicate which features are 1885 * common between the CPUs. The first time this routine gets 1886 * executed, c == &boot_cpu_data. 1887 */ 1888 if (c != &boot_cpu_data) { 1889 /* AND the already accumulated flags with these */ 1890 for (i = 0; i < NCAPINTS; i++) 1891 boot_cpu_data.x86_capability[i] &= c->x86_capability[i]; 1892 1893 /* OR, i.e. replicate the bug flags */ 1894 for (i = NCAPINTS; i < NCAPINTS + NBUGINTS; i++) 1895 c->x86_capability[i] |= boot_cpu_data.x86_capability[i]; 1896 } 1897 1898 ppin_init(c); 1899 1900 /* Init Machine Check Exception if available. */ 1901 mcheck_cpu_init(c); 1902 1903 select_idle_routine(c); 1904 1905 #ifdef CONFIG_NUMA 1906 numa_add_cpu(smp_processor_id()); 1907 #endif 1908 } 1909 1910 /* 1911 * Set up the CPU state needed to execute SYSENTER/SYSEXIT instructions 1912 * on 32-bit kernels: 1913 */ 1914 #ifdef CONFIG_X86_32 1915 void enable_sep_cpu(void) 1916 { 1917 struct tss_struct *tss; 1918 int cpu; 1919 1920 if (!boot_cpu_has(X86_FEATURE_SEP)) 1921 return; 1922 1923 cpu = get_cpu(); 1924 tss = &per_cpu(cpu_tss_rw, cpu); 1925 1926 /* 1927 * We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field -- 1928 * see the big comment in struct x86_hw_tss's definition. 1929 */ 1930 1931 tss->x86_tss.ss1 = __KERNEL_CS; 1932 wrmsr(MSR_IA32_SYSENTER_CS, tss->x86_tss.ss1, 0); 1933 wrmsr(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_entry_stack(cpu) + 1), 0); 1934 wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0); 1935 1936 put_cpu(); 1937 } 1938 #endif 1939 1940 void __init identify_boot_cpu(void) 1941 { 1942 identify_cpu(&boot_cpu_data); 1943 if (HAS_KERNEL_IBT && cpu_feature_enabled(X86_FEATURE_IBT)) 1944 pr_info("CET detected: Indirect Branch Tracking enabled\n"); 1945 #ifdef CONFIG_X86_32 1946 enable_sep_cpu(); 1947 #endif 1948 cpu_detect_tlb(&boot_cpu_data); 1949 setup_cr_pinning(); 1950 1951 tsx_init(); 1952 lkgs_init(); 1953 } 1954 1955 void identify_secondary_cpu(struct cpuinfo_x86 *c) 1956 { 1957 BUG_ON(c == &boot_cpu_data); 1958 identify_cpu(c); 1959 #ifdef CONFIG_X86_32 1960 enable_sep_cpu(); 1961 #endif 1962 validate_apic_and_package_id(c); 1963 x86_spec_ctrl_setup_ap(); 1964 update_srbds_msr(); 1965 1966 tsx_ap_init(); 1967 } 1968 1969 void print_cpu_info(struct cpuinfo_x86 *c) 1970 { 1971 const char *vendor = NULL; 1972 1973 if (c->x86_vendor < X86_VENDOR_NUM) { 1974 vendor = this_cpu->c_vendor; 1975 } else { 1976 if (c->cpuid_level >= 0) 1977 vendor = c->x86_vendor_id; 1978 } 1979 1980 if (vendor && !strstr(c->x86_model_id, vendor)) 1981 pr_cont("%s ", vendor); 1982 1983 if (c->x86_model_id[0]) 1984 pr_cont("%s", c->x86_model_id); 1985 else 1986 pr_cont("%d86", c->x86); 1987 1988 pr_cont(" (family: 0x%x, model: 0x%x", c->x86, c->x86_model); 1989 1990 if (c->x86_stepping || c->cpuid_level >= 0) 1991 pr_cont(", stepping: 0x%x)\n", c->x86_stepping); 1992 else 1993 pr_cont(")\n"); 1994 } 1995 1996 /* 1997 * clearcpuid= was already parsed in cpu_parse_early_param(). This dummy 1998 * function prevents it from becoming an environment variable for init. 1999 */ 2000 static __init int setup_clearcpuid(char *arg) 2001 { 2002 return 1; 2003 } 2004 __setup("clearcpuid=", setup_clearcpuid); 2005 2006 DEFINE_PER_CPU_ALIGNED(struct pcpu_hot, pcpu_hot) = { 2007 .current_task = &init_task, 2008 .preempt_count = INIT_PREEMPT_COUNT, 2009 .top_of_stack = TOP_OF_INIT_STACK, 2010 }; 2011 EXPORT_PER_CPU_SYMBOL(pcpu_hot); 2012 2013 #ifdef CONFIG_X86_64 2014 DEFINE_PER_CPU_FIRST(struct fixed_percpu_data, 2015 fixed_percpu_data) __aligned(PAGE_SIZE) __visible; 2016 EXPORT_PER_CPU_SYMBOL_GPL(fixed_percpu_data); 2017 2018 static void wrmsrl_cstar(unsigned long val) 2019 { 2020 /* 2021 * Intel CPUs do not support 32-bit SYSCALL. Writing to MSR_CSTAR 2022 * is so far ignored by the CPU, but raises a #VE trap in a TDX 2023 * guest. Avoid the pointless write on all Intel CPUs. 2024 */ 2025 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) 2026 wrmsrl(MSR_CSTAR, val); 2027 } 2028 2029 /* May not be marked __init: used by software suspend */ 2030 void syscall_init(void) 2031 { 2032 wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS); 2033 wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64); 2034 2035 #ifdef CONFIG_IA32_EMULATION 2036 wrmsrl_cstar((unsigned long)entry_SYSCALL_compat); 2037 /* 2038 * This only works on Intel CPUs. 2039 * On AMD CPUs these MSRs are 32-bit, CPU truncates MSR_IA32_SYSENTER_EIP. 2040 * This does not cause SYSENTER to jump to the wrong location, because 2041 * AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit). 2042 */ 2043 wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS); 2044 wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 2045 (unsigned long)(cpu_entry_stack(smp_processor_id()) + 1)); 2046 wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat); 2047 #else 2048 wrmsrl_cstar((unsigned long)ignore_sysret); 2049 wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG); 2050 wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL); 2051 wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL); 2052 #endif 2053 2054 /* 2055 * Flags to clear on syscall; clear as much as possible 2056 * to minimize user space-kernel interference. 2057 */ 2058 wrmsrl(MSR_SYSCALL_MASK, 2059 X86_EFLAGS_CF|X86_EFLAGS_PF|X86_EFLAGS_AF| 2060 X86_EFLAGS_ZF|X86_EFLAGS_SF|X86_EFLAGS_TF| 2061 X86_EFLAGS_IF|X86_EFLAGS_DF|X86_EFLAGS_OF| 2062 X86_EFLAGS_IOPL|X86_EFLAGS_NT|X86_EFLAGS_RF| 2063 X86_EFLAGS_AC|X86_EFLAGS_ID); 2064 } 2065 2066 #else /* CONFIG_X86_64 */ 2067 2068 #ifdef CONFIG_STACKPROTECTOR 2069 DEFINE_PER_CPU(unsigned long, __stack_chk_guard); 2070 EXPORT_PER_CPU_SYMBOL(__stack_chk_guard); 2071 #endif 2072 2073 #endif /* CONFIG_X86_64 */ 2074 2075 /* 2076 * Clear all 6 debug registers: 2077 */ 2078 static void clear_all_debug_regs(void) 2079 { 2080 int i; 2081 2082 for (i = 0; i < 8; i++) { 2083 /* Ignore db4, db5 */ 2084 if ((i == 4) || (i == 5)) 2085 continue; 2086 2087 set_debugreg(0, i); 2088 } 2089 } 2090 2091 #ifdef CONFIG_KGDB 2092 /* 2093 * Restore debug regs if using kgdbwait and you have a kernel debugger 2094 * connection established. 2095 */ 2096 static void dbg_restore_debug_regs(void) 2097 { 2098 if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break)) 2099 arch_kgdb_ops.correct_hw_break(); 2100 } 2101 #else /* ! CONFIG_KGDB */ 2102 #define dbg_restore_debug_regs() 2103 #endif /* ! CONFIG_KGDB */ 2104 2105 static inline void setup_getcpu(int cpu) 2106 { 2107 unsigned long cpudata = vdso_encode_cpunode(cpu, early_cpu_to_node(cpu)); 2108 struct desc_struct d = { }; 2109 2110 if (boot_cpu_has(X86_FEATURE_RDTSCP) || boot_cpu_has(X86_FEATURE_RDPID)) 2111 wrmsr(MSR_TSC_AUX, cpudata, 0); 2112 2113 /* Store CPU and node number in limit. */ 2114 d.limit0 = cpudata; 2115 d.limit1 = cpudata >> 16; 2116 2117 d.type = 5; /* RO data, expand down, accessed */ 2118 d.dpl = 3; /* Visible to user code */ 2119 d.s = 1; /* Not a system segment */ 2120 d.p = 1; /* Present */ 2121 d.d = 1; /* 32-bit */ 2122 2123 write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_CPUNODE, &d, DESCTYPE_S); 2124 } 2125 2126 #ifdef CONFIG_X86_64 2127 static inline void ucode_cpu_init(int cpu) { } 2128 2129 static inline void tss_setup_ist(struct tss_struct *tss) 2130 { 2131 /* Set up the per-CPU TSS IST stacks */ 2132 tss->x86_tss.ist[IST_INDEX_DF] = __this_cpu_ist_top_va(DF); 2133 tss->x86_tss.ist[IST_INDEX_NMI] = __this_cpu_ist_top_va(NMI); 2134 tss->x86_tss.ist[IST_INDEX_DB] = __this_cpu_ist_top_va(DB); 2135 tss->x86_tss.ist[IST_INDEX_MCE] = __this_cpu_ist_top_va(MCE); 2136 /* Only mapped when SEV-ES is active */ 2137 tss->x86_tss.ist[IST_INDEX_VC] = __this_cpu_ist_top_va(VC); 2138 } 2139 2140 #else /* CONFIG_X86_64 */ 2141 2142 static inline void ucode_cpu_init(int cpu) 2143 { 2144 show_ucode_info_early(); 2145 } 2146 2147 static inline void tss_setup_ist(struct tss_struct *tss) { } 2148 2149 #endif /* !CONFIG_X86_64 */ 2150 2151 static inline void tss_setup_io_bitmap(struct tss_struct *tss) 2152 { 2153 tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID; 2154 2155 #ifdef CONFIG_X86_IOPL_IOPERM 2156 tss->io_bitmap.prev_max = 0; 2157 tss->io_bitmap.prev_sequence = 0; 2158 memset(tss->io_bitmap.bitmap, 0xff, sizeof(tss->io_bitmap.bitmap)); 2159 /* 2160 * Invalidate the extra array entry past the end of the all 2161 * permission bitmap as required by the hardware. 2162 */ 2163 tss->io_bitmap.mapall[IO_BITMAP_LONGS] = ~0UL; 2164 #endif 2165 } 2166 2167 /* 2168 * Setup everything needed to handle exceptions from the IDT, including the IST 2169 * exceptions which use paranoid_entry(). 2170 */ 2171 void cpu_init_exception_handling(void) 2172 { 2173 struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw); 2174 int cpu = raw_smp_processor_id(); 2175 2176 /* paranoid_entry() gets the CPU number from the GDT */ 2177 setup_getcpu(cpu); 2178 2179 /* IST vectors need TSS to be set up. */ 2180 tss_setup_ist(tss); 2181 tss_setup_io_bitmap(tss); 2182 set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); 2183 2184 load_TR_desc(); 2185 2186 /* GHCB needs to be setup to handle #VC. */ 2187 setup_ghcb(); 2188 2189 /* Finally load the IDT */ 2190 load_current_idt(); 2191 } 2192 2193 /* 2194 * cpu_init() initializes state that is per-CPU. Some data is already 2195 * initialized (naturally) in the bootstrap process, such as the GDT. We 2196 * reload it nevertheless, this function acts as a 'CPU state barrier', 2197 * nothing should get across. 2198 */ 2199 void cpu_init(void) 2200 { 2201 struct task_struct *cur = current; 2202 int cpu = raw_smp_processor_id(); 2203 2204 ucode_cpu_init(cpu); 2205 2206 #ifdef CONFIG_NUMA 2207 if (this_cpu_read(numa_node) == 0 && 2208 early_cpu_to_node(cpu) != NUMA_NO_NODE) 2209 set_numa_node(early_cpu_to_node(cpu)); 2210 #endif 2211 pr_debug("Initializing CPU#%d\n", cpu); 2212 2213 if (IS_ENABLED(CONFIG_X86_64) || cpu_feature_enabled(X86_FEATURE_VME) || 2214 boot_cpu_has(X86_FEATURE_TSC) || boot_cpu_has(X86_FEATURE_DE)) 2215 cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE); 2216 2217 if (IS_ENABLED(CONFIG_X86_64)) { 2218 loadsegment(fs, 0); 2219 memset(cur->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8); 2220 syscall_init(); 2221 2222 wrmsrl(MSR_FS_BASE, 0); 2223 wrmsrl(MSR_KERNEL_GS_BASE, 0); 2224 barrier(); 2225 2226 x2apic_setup(); 2227 } 2228 2229 mmgrab(&init_mm); 2230 cur->active_mm = &init_mm; 2231 BUG_ON(cur->mm); 2232 initialize_tlbstate_and_flush(); 2233 enter_lazy_tlb(&init_mm, cur); 2234 2235 /* 2236 * sp0 points to the entry trampoline stack regardless of what task 2237 * is running. 2238 */ 2239 load_sp0((unsigned long)(cpu_entry_stack(cpu) + 1)); 2240 2241 load_mm_ldt(&init_mm); 2242 2243 clear_all_debug_regs(); 2244 dbg_restore_debug_regs(); 2245 2246 doublefault_init_cpu_tss(); 2247 2248 if (is_uv_system()) 2249 uv_cpu_init(); 2250 2251 load_fixmap_gdt(cpu); 2252 } 2253 2254 #ifdef CONFIG_MICROCODE_LATE_LOADING 2255 /** 2256 * store_cpu_caps() - Store a snapshot of CPU capabilities 2257 * @curr_info: Pointer where to store it 2258 * 2259 * Returns: None 2260 */ 2261 void store_cpu_caps(struct cpuinfo_x86 *curr_info) 2262 { 2263 /* Reload CPUID max function as it might've changed. */ 2264 curr_info->cpuid_level = cpuid_eax(0); 2265 2266 /* Copy all capability leafs and pick up the synthetic ones. */ 2267 memcpy(&curr_info->x86_capability, &boot_cpu_data.x86_capability, 2268 sizeof(curr_info->x86_capability)); 2269 2270 /* Get the hardware CPUID leafs */ 2271 get_cpu_cap(curr_info); 2272 } 2273 2274 /** 2275 * microcode_check() - Check if any CPU capabilities changed after an update. 2276 * @prev_info: CPU capabilities stored before an update. 2277 * 2278 * The microcode loader calls this upon late microcode load to recheck features, 2279 * only when microcode has been updated. Caller holds microcode_mutex and CPU 2280 * hotplug lock. 2281 * 2282 * Return: None 2283 */ 2284 void microcode_check(struct cpuinfo_x86 *prev_info) 2285 { 2286 struct cpuinfo_x86 curr_info; 2287 2288 perf_check_microcode(); 2289 2290 store_cpu_caps(&curr_info); 2291 2292 if (!memcmp(&prev_info->x86_capability, &curr_info.x86_capability, 2293 sizeof(prev_info->x86_capability))) 2294 return; 2295 2296 pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n"); 2297 pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n"); 2298 } 2299 #endif 2300 2301 /* 2302 * Invoked from core CPU hotplug code after hotplug operations 2303 */ 2304 void arch_smt_update(void) 2305 { 2306 /* Handle the speculative execution misfeatures */ 2307 cpu_bugs_smt_update(); 2308 /* Check whether IPI broadcasting can be enabled */ 2309 apic_smt_update(); 2310 } 2311 2312 void __init arch_cpu_finalize_init(void) 2313 { 2314 identify_boot_cpu(); 2315 2316 /* 2317 * identify_boot_cpu() initialized SMT support information, let the 2318 * core code know. 2319 */ 2320 cpu_smt_check_topology(); 2321 2322 if (!IS_ENABLED(CONFIG_SMP)) { 2323 pr_info("CPU: "); 2324 print_cpu_info(&boot_cpu_data); 2325 } 2326 2327 cpu_select_mitigations(); 2328 2329 arch_smt_update(); 2330 2331 if (IS_ENABLED(CONFIG_X86_32)) { 2332 /* 2333 * Check whether this is a real i386 which is not longer 2334 * supported and fixup the utsname. 2335 */ 2336 if (boot_cpu_data.x86 < 4) 2337 panic("Kernel requires i486+ for 'invlpg' and other features"); 2338 2339 init_utsname()->machine[1] = 2340 '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86); 2341 } 2342 2343 /* 2344 * Must be before alternatives because it might set or clear 2345 * feature bits. 2346 */ 2347 fpu__init_system(); 2348 fpu__init_cpu(); 2349 2350 alternative_instructions(); 2351 2352 if (IS_ENABLED(CONFIG_X86_64)) { 2353 /* 2354 * Make sure the first 2MB area is not mapped by huge pages 2355 * There are typically fixed size MTRRs in there and overlapping 2356 * MTRRs into large pages causes slow downs. 2357 * 2358 * Right now we don't do that with gbpages because there seems 2359 * very little benefit for that case. 2360 */ 2361 if (!direct_gbpages) 2362 set_memory_4k((unsigned long)__va(0), 1); 2363 } else { 2364 fpu__init_check_bugs(); 2365 } 2366 2367 /* 2368 * This needs to be called before any devices perform DMA 2369 * operations that might use the SWIOTLB bounce buffers. It will 2370 * mark the bounce buffers as decrypted so that their usage will 2371 * not cause "plain-text" data to be decrypted when accessed. It 2372 * must be called after late_time_init() so that Hyper-V x86/x64 2373 * hypercalls work when the SWIOTLB bounce buffers are decrypted. 2374 */ 2375 mem_encrypt_init(); 2376 } 2377