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/smp.h> 22 #include <linux/io.h> 23 #include <linux/syscore_ops.h> 24 #include <linux/pgtable.h> 25 26 #include <asm/cmdline.h> 27 #include <asm/stackprotector.h> 28 #include <asm/perf_event.h> 29 #include <asm/mmu_context.h> 30 #include <asm/doublefault.h> 31 #include <asm/archrandom.h> 32 #include <asm/hypervisor.h> 33 #include <asm/processor.h> 34 #include <asm/tlbflush.h> 35 #include <asm/debugreg.h> 36 #include <asm/sections.h> 37 #include <asm/vsyscall.h> 38 #include <linux/topology.h> 39 #include <linux/cpumask.h> 40 #include <linux/atomic.h> 41 #include <asm/proto.h> 42 #include <asm/setup.h> 43 #include <asm/apic.h> 44 #include <asm/desc.h> 45 #include <asm/fpu/api.h> 46 #include <asm/mtrr.h> 47 #include <asm/hwcap2.h> 48 #include <linux/numa.h> 49 #include <asm/numa.h> 50 #include <asm/asm.h> 51 #include <asm/bugs.h> 52 #include <asm/cpu.h> 53 #include <asm/mce.h> 54 #include <asm/msr.h> 55 #include <asm/memtype.h> 56 #include <asm/microcode.h> 57 #include <asm/microcode_intel.h> 58 #include <asm/intel-family.h> 59 #include <asm/cpu_device_id.h> 60 #include <asm/uv/uv.h> 61 #include <asm/sigframe.h> 62 #include <asm/traps.h> 63 #include <asm/sev.h> 64 65 #include "cpu.h" 66 67 u32 elf_hwcap2 __read_mostly; 68 69 /* all of these masks are initialized in setup_cpu_local_masks() */ 70 cpumask_var_t cpu_initialized_mask; 71 cpumask_var_t cpu_callout_mask; 72 cpumask_var_t cpu_callin_mask; 73 74 /* representing cpus for which sibling maps can be computed */ 75 cpumask_var_t cpu_sibling_setup_mask; 76 77 /* Number of siblings per CPU package */ 78 int smp_num_siblings = 1; 79 EXPORT_SYMBOL(smp_num_siblings); 80 81 /* Last level cache ID of each logical CPU */ 82 DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id) = BAD_APICID; 83 84 u16 get_llc_id(unsigned int cpu) 85 { 86 return per_cpu(cpu_llc_id, cpu); 87 } 88 EXPORT_SYMBOL_GPL(get_llc_id); 89 90 /* L2 cache ID of each logical CPU */ 91 DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_l2c_id) = BAD_APICID; 92 93 static struct ppin_info { 94 int feature; 95 int msr_ppin_ctl; 96 int msr_ppin; 97 } ppin_info[] = { 98 [X86_VENDOR_INTEL] = { 99 .feature = X86_FEATURE_INTEL_PPIN, 100 .msr_ppin_ctl = MSR_PPIN_CTL, 101 .msr_ppin = MSR_PPIN 102 }, 103 [X86_VENDOR_AMD] = { 104 .feature = X86_FEATURE_AMD_PPIN, 105 .msr_ppin_ctl = MSR_AMD_PPIN_CTL, 106 .msr_ppin = MSR_AMD_PPIN 107 }, 108 }; 109 110 static const struct x86_cpu_id ppin_cpuids[] = { 111 X86_MATCH_FEATURE(X86_FEATURE_AMD_PPIN, &ppin_info[X86_VENDOR_AMD]), 112 X86_MATCH_FEATURE(X86_FEATURE_INTEL_PPIN, &ppin_info[X86_VENDOR_INTEL]), 113 114 /* Legacy models without CPUID enumeration */ 115 X86_MATCH_INTEL_FAM6_MODEL(IVYBRIDGE_X, &ppin_info[X86_VENDOR_INTEL]), 116 X86_MATCH_INTEL_FAM6_MODEL(HASWELL_X, &ppin_info[X86_VENDOR_INTEL]), 117 X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_D, &ppin_info[X86_VENDOR_INTEL]), 118 X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_X, &ppin_info[X86_VENDOR_INTEL]), 119 X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_X, &ppin_info[X86_VENDOR_INTEL]), 120 X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X, &ppin_info[X86_VENDOR_INTEL]), 121 X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D, &ppin_info[X86_VENDOR_INTEL]), 122 X86_MATCH_INTEL_FAM6_MODEL(SAPPHIRERAPIDS_X, &ppin_info[X86_VENDOR_INTEL]), 123 X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNL, &ppin_info[X86_VENDOR_INTEL]), 124 X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNM, &ppin_info[X86_VENDOR_INTEL]), 125 126 {} 127 }; 128 129 static void ppin_init(struct cpuinfo_x86 *c) 130 { 131 const struct x86_cpu_id *id; 132 unsigned long long val; 133 struct ppin_info *info; 134 135 id = x86_match_cpu(ppin_cpuids); 136 if (!id) 137 return; 138 139 /* 140 * Testing the presence of the MSR is not enough. Need to check 141 * that the PPIN_CTL allows reading of the PPIN. 142 */ 143 info = (struct ppin_info *)id->driver_data; 144 145 if (rdmsrl_safe(info->msr_ppin_ctl, &val)) 146 goto clear_ppin; 147 148 if ((val & 3UL) == 1UL) { 149 /* PPIN locked in disabled mode */ 150 goto clear_ppin; 151 } 152 153 /* If PPIN is disabled, try to enable */ 154 if (!(val & 2UL)) { 155 wrmsrl_safe(info->msr_ppin_ctl, val | 2UL); 156 rdmsrl_safe(info->msr_ppin_ctl, &val); 157 } 158 159 /* Is the enable bit set? */ 160 if (val & 2UL) { 161 c->ppin = __rdmsr(info->msr_ppin); 162 set_cpu_cap(c, info->feature); 163 return; 164 } 165 166 clear_ppin: 167 clear_cpu_cap(c, info->feature); 168 } 169 170 /* correctly size the local cpu masks */ 171 void __init setup_cpu_local_masks(void) 172 { 173 alloc_bootmem_cpumask_var(&cpu_initialized_mask); 174 alloc_bootmem_cpumask_var(&cpu_callin_mask); 175 alloc_bootmem_cpumask_var(&cpu_callout_mask); 176 alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask); 177 } 178 179 static void default_init(struct cpuinfo_x86 *c) 180 { 181 #ifdef CONFIG_X86_64 182 cpu_detect_cache_sizes(c); 183 #else 184 /* Not much we can do here... */ 185 /* Check if at least it has cpuid */ 186 if (c->cpuid_level == -1) { 187 /* No cpuid. It must be an ancient CPU */ 188 if (c->x86 == 4) 189 strcpy(c->x86_model_id, "486"); 190 else if (c->x86 == 3) 191 strcpy(c->x86_model_id, "386"); 192 } 193 #endif 194 } 195 196 static const struct cpu_dev default_cpu = { 197 .c_init = default_init, 198 .c_vendor = "Unknown", 199 .c_x86_vendor = X86_VENDOR_UNKNOWN, 200 }; 201 202 static const struct cpu_dev *this_cpu = &default_cpu; 203 204 DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = { 205 #ifdef CONFIG_X86_64 206 /* 207 * We need valid kernel segments for data and code in long mode too 208 * IRET will check the segment types kkeil 2000/10/28 209 * Also sysret mandates a special GDT layout 210 * 211 * TLS descriptors are currently at a different place compared to i386. 212 * Hopefully nobody expects them at a fixed place (Wine?) 213 */ 214 [GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(0xc09b, 0, 0xfffff), 215 [GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(0xa09b, 0, 0xfffff), 216 [GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(0xc093, 0, 0xfffff), 217 [GDT_ENTRY_DEFAULT_USER32_CS] = GDT_ENTRY_INIT(0xc0fb, 0, 0xfffff), 218 [GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(0xc0f3, 0, 0xfffff), 219 [GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(0xa0fb, 0, 0xfffff), 220 #else 221 [GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(0xc09a, 0, 0xfffff), 222 [GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff), 223 [GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(0xc0fa, 0, 0xfffff), 224 [GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(0xc0f2, 0, 0xfffff), 225 /* 226 * Segments used for calling PnP BIOS have byte granularity. 227 * They code segments and data segments have fixed 64k limits, 228 * the transfer segment sizes are set at run time. 229 */ 230 /* 32-bit code */ 231 [GDT_ENTRY_PNPBIOS_CS32] = GDT_ENTRY_INIT(0x409a, 0, 0xffff), 232 /* 16-bit code */ 233 [GDT_ENTRY_PNPBIOS_CS16] = GDT_ENTRY_INIT(0x009a, 0, 0xffff), 234 /* 16-bit data */ 235 [GDT_ENTRY_PNPBIOS_DS] = GDT_ENTRY_INIT(0x0092, 0, 0xffff), 236 /* 16-bit data */ 237 [GDT_ENTRY_PNPBIOS_TS1] = GDT_ENTRY_INIT(0x0092, 0, 0), 238 /* 16-bit data */ 239 [GDT_ENTRY_PNPBIOS_TS2] = GDT_ENTRY_INIT(0x0092, 0, 0), 240 /* 241 * The APM segments have byte granularity and their bases 242 * are set at run time. All have 64k limits. 243 */ 244 /* 32-bit code */ 245 [GDT_ENTRY_APMBIOS_BASE] = GDT_ENTRY_INIT(0x409a, 0, 0xffff), 246 /* 16-bit code */ 247 [GDT_ENTRY_APMBIOS_BASE+1] = GDT_ENTRY_INIT(0x009a, 0, 0xffff), 248 /* data */ 249 [GDT_ENTRY_APMBIOS_BASE+2] = GDT_ENTRY_INIT(0x4092, 0, 0xffff), 250 251 [GDT_ENTRY_ESPFIX_SS] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff), 252 [GDT_ENTRY_PERCPU] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff), 253 #endif 254 } }; 255 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page); 256 257 #ifdef CONFIG_X86_64 258 static int __init x86_nopcid_setup(char *s) 259 { 260 /* nopcid doesn't accept parameters */ 261 if (s) 262 return -EINVAL; 263 264 /* do not emit a message if the feature is not present */ 265 if (!boot_cpu_has(X86_FEATURE_PCID)) 266 return 0; 267 268 setup_clear_cpu_cap(X86_FEATURE_PCID); 269 pr_info("nopcid: PCID feature disabled\n"); 270 return 0; 271 } 272 early_param("nopcid", x86_nopcid_setup); 273 #endif 274 275 static int __init x86_noinvpcid_setup(char *s) 276 { 277 /* noinvpcid doesn't accept parameters */ 278 if (s) 279 return -EINVAL; 280 281 /* do not emit a message if the feature is not present */ 282 if (!boot_cpu_has(X86_FEATURE_INVPCID)) 283 return 0; 284 285 setup_clear_cpu_cap(X86_FEATURE_INVPCID); 286 pr_info("noinvpcid: INVPCID feature disabled\n"); 287 return 0; 288 } 289 early_param("noinvpcid", x86_noinvpcid_setup); 290 291 #ifdef CONFIG_X86_32 292 static int cachesize_override = -1; 293 static int disable_x86_serial_nr = 1; 294 295 static int __init cachesize_setup(char *str) 296 { 297 get_option(&str, &cachesize_override); 298 return 1; 299 } 300 __setup("cachesize=", cachesize_setup); 301 302 /* Standard macro to see if a specific flag is changeable */ 303 static inline int flag_is_changeable_p(u32 flag) 304 { 305 u32 f1, f2; 306 307 /* 308 * Cyrix and IDT cpus allow disabling of CPUID 309 * so the code below may return different results 310 * when it is executed before and after enabling 311 * the CPUID. Add "volatile" to not allow gcc to 312 * optimize the subsequent calls to this function. 313 */ 314 asm volatile ("pushfl \n\t" 315 "pushfl \n\t" 316 "popl %0 \n\t" 317 "movl %0, %1 \n\t" 318 "xorl %2, %0 \n\t" 319 "pushl %0 \n\t" 320 "popfl \n\t" 321 "pushfl \n\t" 322 "popl %0 \n\t" 323 "popfl \n\t" 324 325 : "=&r" (f1), "=&r" (f2) 326 : "ir" (flag)); 327 328 return ((f1^f2) & flag) != 0; 329 } 330 331 /* Probe for the CPUID instruction */ 332 int have_cpuid_p(void) 333 { 334 return flag_is_changeable_p(X86_EFLAGS_ID); 335 } 336 337 static void squash_the_stupid_serial_number(struct cpuinfo_x86 *c) 338 { 339 unsigned long lo, hi; 340 341 if (!cpu_has(c, X86_FEATURE_PN) || !disable_x86_serial_nr) 342 return; 343 344 /* Disable processor serial number: */ 345 346 rdmsr(MSR_IA32_BBL_CR_CTL, lo, hi); 347 lo |= 0x200000; 348 wrmsr(MSR_IA32_BBL_CR_CTL, lo, hi); 349 350 pr_notice("CPU serial number disabled.\n"); 351 clear_cpu_cap(c, X86_FEATURE_PN); 352 353 /* Disabling the serial number may affect the cpuid level */ 354 c->cpuid_level = cpuid_eax(0); 355 } 356 357 static int __init x86_serial_nr_setup(char *s) 358 { 359 disable_x86_serial_nr = 0; 360 return 1; 361 } 362 __setup("serialnumber", x86_serial_nr_setup); 363 #else 364 static inline int flag_is_changeable_p(u32 flag) 365 { 366 return 1; 367 } 368 static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c) 369 { 370 } 371 #endif 372 373 static __always_inline void setup_smep(struct cpuinfo_x86 *c) 374 { 375 if (cpu_has(c, X86_FEATURE_SMEP)) 376 cr4_set_bits(X86_CR4_SMEP); 377 } 378 379 static __always_inline void setup_smap(struct cpuinfo_x86 *c) 380 { 381 unsigned long eflags = native_save_fl(); 382 383 /* This should have been cleared long ago */ 384 BUG_ON(eflags & X86_EFLAGS_AC); 385 386 if (cpu_has(c, X86_FEATURE_SMAP)) 387 cr4_set_bits(X86_CR4_SMAP); 388 } 389 390 static __always_inline void setup_umip(struct cpuinfo_x86 *c) 391 { 392 /* Check the boot processor, plus build option for UMIP. */ 393 if (!cpu_feature_enabled(X86_FEATURE_UMIP)) 394 goto out; 395 396 /* Check the current processor's cpuid bits. */ 397 if (!cpu_has(c, X86_FEATURE_UMIP)) 398 goto out; 399 400 cr4_set_bits(X86_CR4_UMIP); 401 402 pr_info_once("x86/cpu: User Mode Instruction Prevention (UMIP) activated\n"); 403 404 return; 405 406 out: 407 /* 408 * Make sure UMIP is disabled in case it was enabled in a 409 * previous boot (e.g., via kexec). 410 */ 411 cr4_clear_bits(X86_CR4_UMIP); 412 } 413 414 /* These bits should not change their value after CPU init is finished. */ 415 static const unsigned long cr4_pinned_mask = 416 X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_UMIP | 417 X86_CR4_FSGSBASE | X86_CR4_CET; 418 static DEFINE_STATIC_KEY_FALSE_RO(cr_pinning); 419 static unsigned long cr4_pinned_bits __ro_after_init; 420 421 void native_write_cr0(unsigned long val) 422 { 423 unsigned long bits_missing = 0; 424 425 set_register: 426 asm volatile("mov %0,%%cr0": "+r" (val) : : "memory"); 427 428 if (static_branch_likely(&cr_pinning)) { 429 if (unlikely((val & X86_CR0_WP) != X86_CR0_WP)) { 430 bits_missing = X86_CR0_WP; 431 val |= bits_missing; 432 goto set_register; 433 } 434 /* Warn after we've set the missing bits. */ 435 WARN_ONCE(bits_missing, "CR0 WP bit went missing!?\n"); 436 } 437 } 438 EXPORT_SYMBOL(native_write_cr0); 439 440 void __no_profile native_write_cr4(unsigned long val) 441 { 442 unsigned long bits_changed = 0; 443 444 set_register: 445 asm volatile("mov %0,%%cr4": "+r" (val) : : "memory"); 446 447 if (static_branch_likely(&cr_pinning)) { 448 if (unlikely((val & cr4_pinned_mask) != cr4_pinned_bits)) { 449 bits_changed = (val & cr4_pinned_mask) ^ cr4_pinned_bits; 450 val = (val & ~cr4_pinned_mask) | cr4_pinned_bits; 451 goto set_register; 452 } 453 /* Warn after we've corrected the changed bits. */ 454 WARN_ONCE(bits_changed, "pinned CR4 bits changed: 0x%lx!?\n", 455 bits_changed); 456 } 457 } 458 #if IS_MODULE(CONFIG_LKDTM) 459 EXPORT_SYMBOL_GPL(native_write_cr4); 460 #endif 461 462 void cr4_update_irqsoff(unsigned long set, unsigned long clear) 463 { 464 unsigned long newval, cr4 = this_cpu_read(cpu_tlbstate.cr4); 465 466 lockdep_assert_irqs_disabled(); 467 468 newval = (cr4 & ~clear) | set; 469 if (newval != cr4) { 470 this_cpu_write(cpu_tlbstate.cr4, newval); 471 __write_cr4(newval); 472 } 473 } 474 EXPORT_SYMBOL(cr4_update_irqsoff); 475 476 /* Read the CR4 shadow. */ 477 unsigned long cr4_read_shadow(void) 478 { 479 return this_cpu_read(cpu_tlbstate.cr4); 480 } 481 EXPORT_SYMBOL_GPL(cr4_read_shadow); 482 483 void cr4_init(void) 484 { 485 unsigned long cr4 = __read_cr4(); 486 487 if (boot_cpu_has(X86_FEATURE_PCID)) 488 cr4 |= X86_CR4_PCIDE; 489 if (static_branch_likely(&cr_pinning)) 490 cr4 = (cr4 & ~cr4_pinned_mask) | cr4_pinned_bits; 491 492 __write_cr4(cr4); 493 494 /* Initialize cr4 shadow for this CPU. */ 495 this_cpu_write(cpu_tlbstate.cr4, cr4); 496 } 497 498 /* 499 * Once CPU feature detection is finished (and boot params have been 500 * parsed), record any of the sensitive CR bits that are set, and 501 * enable CR pinning. 502 */ 503 static void __init setup_cr_pinning(void) 504 { 505 cr4_pinned_bits = this_cpu_read(cpu_tlbstate.cr4) & cr4_pinned_mask; 506 static_key_enable(&cr_pinning.key); 507 } 508 509 static __init int x86_nofsgsbase_setup(char *arg) 510 { 511 /* Require an exact match without trailing characters. */ 512 if (strlen(arg)) 513 return 0; 514 515 /* Do not emit a message if the feature is not present. */ 516 if (!boot_cpu_has(X86_FEATURE_FSGSBASE)) 517 return 1; 518 519 setup_clear_cpu_cap(X86_FEATURE_FSGSBASE); 520 pr_info("FSGSBASE disabled via kernel command line\n"); 521 return 1; 522 } 523 __setup("nofsgsbase", x86_nofsgsbase_setup); 524 525 /* 526 * Protection Keys are not available in 32-bit mode. 527 */ 528 static bool pku_disabled; 529 530 static __always_inline void setup_pku(struct cpuinfo_x86 *c) 531 { 532 if (c == &boot_cpu_data) { 533 if (pku_disabled || !cpu_feature_enabled(X86_FEATURE_PKU)) 534 return; 535 /* 536 * Setting CR4.PKE will cause the X86_FEATURE_OSPKE cpuid 537 * bit to be set. Enforce it. 538 */ 539 setup_force_cpu_cap(X86_FEATURE_OSPKE); 540 541 } else if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) { 542 return; 543 } 544 545 cr4_set_bits(X86_CR4_PKE); 546 /* Load the default PKRU value */ 547 pkru_write_default(); 548 } 549 550 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 551 static __init int setup_disable_pku(char *arg) 552 { 553 /* 554 * Do not clear the X86_FEATURE_PKU bit. All of the 555 * runtime checks are against OSPKE so clearing the 556 * bit does nothing. 557 * 558 * This way, we will see "pku" in cpuinfo, but not 559 * "ospke", which is exactly what we want. It shows 560 * that the CPU has PKU, but the OS has not enabled it. 561 * This happens to be exactly how a system would look 562 * if we disabled the config option. 563 */ 564 pr_info("x86: 'nopku' specified, disabling Memory Protection Keys\n"); 565 pku_disabled = true; 566 return 1; 567 } 568 __setup("nopku", setup_disable_pku); 569 #endif /* CONFIG_X86_64 */ 570 571 #ifdef CONFIG_X86_KERNEL_IBT 572 573 __noendbr u64 ibt_save(void) 574 { 575 u64 msr = 0; 576 577 if (cpu_feature_enabled(X86_FEATURE_IBT)) { 578 rdmsrl(MSR_IA32_S_CET, msr); 579 wrmsrl(MSR_IA32_S_CET, msr & ~CET_ENDBR_EN); 580 } 581 582 return msr; 583 } 584 585 __noendbr void ibt_restore(u64 save) 586 { 587 u64 msr; 588 589 if (cpu_feature_enabled(X86_FEATURE_IBT)) { 590 rdmsrl(MSR_IA32_S_CET, msr); 591 msr &= ~CET_ENDBR_EN; 592 msr |= (save & CET_ENDBR_EN); 593 wrmsrl(MSR_IA32_S_CET, msr); 594 } 595 } 596 597 #endif 598 599 static __always_inline void setup_cet(struct cpuinfo_x86 *c) 600 { 601 u64 msr = CET_ENDBR_EN; 602 603 if (!HAS_KERNEL_IBT || 604 !cpu_feature_enabled(X86_FEATURE_IBT)) 605 return; 606 607 wrmsrl(MSR_IA32_S_CET, msr); 608 cr4_set_bits(X86_CR4_CET); 609 610 if (!ibt_selftest()) { 611 pr_err("IBT selftest: Failed!\n"); 612 setup_clear_cpu_cap(X86_FEATURE_IBT); 613 return; 614 } 615 } 616 617 __noendbr void cet_disable(void) 618 { 619 if (cpu_feature_enabled(X86_FEATURE_IBT)) 620 wrmsrl(MSR_IA32_S_CET, 0); 621 } 622 623 /* 624 * Some CPU features depend on higher CPUID levels, which may not always 625 * be available due to CPUID level capping or broken virtualization 626 * software. Add those features to this table to auto-disable them. 627 */ 628 struct cpuid_dependent_feature { 629 u32 feature; 630 u32 level; 631 }; 632 633 static const struct cpuid_dependent_feature 634 cpuid_dependent_features[] = { 635 { X86_FEATURE_MWAIT, 0x00000005 }, 636 { X86_FEATURE_DCA, 0x00000009 }, 637 { X86_FEATURE_XSAVE, 0x0000000d }, 638 { 0, 0 } 639 }; 640 641 static void filter_cpuid_features(struct cpuinfo_x86 *c, bool warn) 642 { 643 const struct cpuid_dependent_feature *df; 644 645 for (df = cpuid_dependent_features; df->feature; df++) { 646 647 if (!cpu_has(c, df->feature)) 648 continue; 649 /* 650 * Note: cpuid_level is set to -1 if unavailable, but 651 * extended_extended_level is set to 0 if unavailable 652 * and the legitimate extended levels are all negative 653 * when signed; hence the weird messing around with 654 * signs here... 655 */ 656 if (!((s32)df->level < 0 ? 657 (u32)df->level > (u32)c->extended_cpuid_level : 658 (s32)df->level > (s32)c->cpuid_level)) 659 continue; 660 661 clear_cpu_cap(c, df->feature); 662 if (!warn) 663 continue; 664 665 pr_warn("CPU: CPU feature " X86_CAP_FMT " disabled, no CPUID level 0x%x\n", 666 x86_cap_flag(df->feature), df->level); 667 } 668 } 669 670 /* 671 * Naming convention should be: <Name> [(<Codename>)] 672 * This table only is used unless init_<vendor>() below doesn't set it; 673 * in particular, if CPUID levels 0x80000002..4 are supported, this 674 * isn't used 675 */ 676 677 /* Look up CPU names by table lookup. */ 678 static const char *table_lookup_model(struct cpuinfo_x86 *c) 679 { 680 #ifdef CONFIG_X86_32 681 const struct legacy_cpu_model_info *info; 682 683 if (c->x86_model >= 16) 684 return NULL; /* Range check */ 685 686 if (!this_cpu) 687 return NULL; 688 689 info = this_cpu->legacy_models; 690 691 while (info->family) { 692 if (info->family == c->x86) 693 return info->model_names[c->x86_model]; 694 info++; 695 } 696 #endif 697 return NULL; /* Not found */ 698 } 699 700 /* Aligned to unsigned long to avoid split lock in atomic bitmap ops */ 701 __u32 cpu_caps_cleared[NCAPINTS + NBUGINTS] __aligned(sizeof(unsigned long)); 702 __u32 cpu_caps_set[NCAPINTS + NBUGINTS] __aligned(sizeof(unsigned long)); 703 704 void load_percpu_segment(int cpu) 705 { 706 #ifdef CONFIG_X86_32 707 loadsegment(fs, __KERNEL_PERCPU); 708 #else 709 __loadsegment_simple(gs, 0); 710 wrmsrl(MSR_GS_BASE, cpu_kernelmode_gs_base(cpu)); 711 #endif 712 } 713 714 #ifdef CONFIG_X86_32 715 /* The 32-bit entry code needs to find cpu_entry_area. */ 716 DEFINE_PER_CPU(struct cpu_entry_area *, cpu_entry_area); 717 #endif 718 719 /* Load the original GDT from the per-cpu structure */ 720 void load_direct_gdt(int cpu) 721 { 722 struct desc_ptr gdt_descr; 723 724 gdt_descr.address = (long)get_cpu_gdt_rw(cpu); 725 gdt_descr.size = GDT_SIZE - 1; 726 load_gdt(&gdt_descr); 727 } 728 EXPORT_SYMBOL_GPL(load_direct_gdt); 729 730 /* Load a fixmap remapping of the per-cpu GDT */ 731 void load_fixmap_gdt(int cpu) 732 { 733 struct desc_ptr gdt_descr; 734 735 gdt_descr.address = (long)get_cpu_gdt_ro(cpu); 736 gdt_descr.size = GDT_SIZE - 1; 737 load_gdt(&gdt_descr); 738 } 739 EXPORT_SYMBOL_GPL(load_fixmap_gdt); 740 741 /* 742 * Current gdt points %fs at the "master" per-cpu area: after this, 743 * it's on the real one. 744 */ 745 void switch_to_new_gdt(int cpu) 746 { 747 /* Load the original GDT */ 748 load_direct_gdt(cpu); 749 /* Reload the per-cpu base */ 750 load_percpu_segment(cpu); 751 } 752 753 static const struct cpu_dev *cpu_devs[X86_VENDOR_NUM] = {}; 754 755 static void get_model_name(struct cpuinfo_x86 *c) 756 { 757 unsigned int *v; 758 char *p, *q, *s; 759 760 if (c->extended_cpuid_level < 0x80000004) 761 return; 762 763 v = (unsigned int *)c->x86_model_id; 764 cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]); 765 cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]); 766 cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]); 767 c->x86_model_id[48] = 0; 768 769 /* Trim whitespace */ 770 p = q = s = &c->x86_model_id[0]; 771 772 while (*p == ' ') 773 p++; 774 775 while (*p) { 776 /* Note the last non-whitespace index */ 777 if (!isspace(*p)) 778 s = q; 779 780 *q++ = *p++; 781 } 782 783 *(s + 1) = '\0'; 784 } 785 786 void detect_num_cpu_cores(struct cpuinfo_x86 *c) 787 { 788 unsigned int eax, ebx, ecx, edx; 789 790 c->x86_max_cores = 1; 791 if (!IS_ENABLED(CONFIG_SMP) || c->cpuid_level < 4) 792 return; 793 794 cpuid_count(4, 0, &eax, &ebx, &ecx, &edx); 795 if (eax & 0x1f) 796 c->x86_max_cores = (eax >> 26) + 1; 797 } 798 799 void cpu_detect_cache_sizes(struct cpuinfo_x86 *c) 800 { 801 unsigned int n, dummy, ebx, ecx, edx, l2size; 802 803 n = c->extended_cpuid_level; 804 805 if (n >= 0x80000005) { 806 cpuid(0x80000005, &dummy, &ebx, &ecx, &edx); 807 c->x86_cache_size = (ecx>>24) + (edx>>24); 808 #ifdef CONFIG_X86_64 809 /* On K8 L1 TLB is inclusive, so don't count it */ 810 c->x86_tlbsize = 0; 811 #endif 812 } 813 814 if (n < 0x80000006) /* Some chips just has a large L1. */ 815 return; 816 817 cpuid(0x80000006, &dummy, &ebx, &ecx, &edx); 818 l2size = ecx >> 16; 819 820 #ifdef CONFIG_X86_64 821 c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff); 822 #else 823 /* do processor-specific cache resizing */ 824 if (this_cpu->legacy_cache_size) 825 l2size = this_cpu->legacy_cache_size(c, l2size); 826 827 /* Allow user to override all this if necessary. */ 828 if (cachesize_override != -1) 829 l2size = cachesize_override; 830 831 if (l2size == 0) 832 return; /* Again, no L2 cache is possible */ 833 #endif 834 835 c->x86_cache_size = l2size; 836 } 837 838 u16 __read_mostly tlb_lli_4k[NR_INFO]; 839 u16 __read_mostly tlb_lli_2m[NR_INFO]; 840 u16 __read_mostly tlb_lli_4m[NR_INFO]; 841 u16 __read_mostly tlb_lld_4k[NR_INFO]; 842 u16 __read_mostly tlb_lld_2m[NR_INFO]; 843 u16 __read_mostly tlb_lld_4m[NR_INFO]; 844 u16 __read_mostly tlb_lld_1g[NR_INFO]; 845 846 static void cpu_detect_tlb(struct cpuinfo_x86 *c) 847 { 848 if (this_cpu->c_detect_tlb) 849 this_cpu->c_detect_tlb(c); 850 851 pr_info("Last level iTLB entries: 4KB %d, 2MB %d, 4MB %d\n", 852 tlb_lli_4k[ENTRIES], tlb_lli_2m[ENTRIES], 853 tlb_lli_4m[ENTRIES]); 854 855 pr_info("Last level dTLB entries: 4KB %d, 2MB %d, 4MB %d, 1GB %d\n", 856 tlb_lld_4k[ENTRIES], tlb_lld_2m[ENTRIES], 857 tlb_lld_4m[ENTRIES], tlb_lld_1g[ENTRIES]); 858 } 859 860 int detect_ht_early(struct cpuinfo_x86 *c) 861 { 862 #ifdef CONFIG_SMP 863 u32 eax, ebx, ecx, edx; 864 865 if (!cpu_has(c, X86_FEATURE_HT)) 866 return -1; 867 868 if (cpu_has(c, X86_FEATURE_CMP_LEGACY)) 869 return -1; 870 871 if (cpu_has(c, X86_FEATURE_XTOPOLOGY)) 872 return -1; 873 874 cpuid(1, &eax, &ebx, &ecx, &edx); 875 876 smp_num_siblings = (ebx & 0xff0000) >> 16; 877 if (smp_num_siblings == 1) 878 pr_info_once("CPU0: Hyper-Threading is disabled\n"); 879 #endif 880 return 0; 881 } 882 883 void detect_ht(struct cpuinfo_x86 *c) 884 { 885 #ifdef CONFIG_SMP 886 int index_msb, core_bits; 887 888 if (detect_ht_early(c) < 0) 889 return; 890 891 index_msb = get_count_order(smp_num_siblings); 892 c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb); 893 894 smp_num_siblings = smp_num_siblings / c->x86_max_cores; 895 896 index_msb = get_count_order(smp_num_siblings); 897 898 core_bits = get_count_order(c->x86_max_cores); 899 900 c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, index_msb) & 901 ((1 << core_bits) - 1); 902 #endif 903 } 904 905 static void get_cpu_vendor(struct cpuinfo_x86 *c) 906 { 907 char *v = c->x86_vendor_id; 908 int i; 909 910 for (i = 0; i < X86_VENDOR_NUM; i++) { 911 if (!cpu_devs[i]) 912 break; 913 914 if (!strcmp(v, cpu_devs[i]->c_ident[0]) || 915 (cpu_devs[i]->c_ident[1] && 916 !strcmp(v, cpu_devs[i]->c_ident[1]))) { 917 918 this_cpu = cpu_devs[i]; 919 c->x86_vendor = this_cpu->c_x86_vendor; 920 return; 921 } 922 } 923 924 pr_err_once("CPU: vendor_id '%s' unknown, using generic init.\n" \ 925 "CPU: Your system may be unstable.\n", v); 926 927 c->x86_vendor = X86_VENDOR_UNKNOWN; 928 this_cpu = &default_cpu; 929 } 930 931 void cpu_detect(struct cpuinfo_x86 *c) 932 { 933 /* Get vendor name */ 934 cpuid(0x00000000, (unsigned int *)&c->cpuid_level, 935 (unsigned int *)&c->x86_vendor_id[0], 936 (unsigned int *)&c->x86_vendor_id[8], 937 (unsigned int *)&c->x86_vendor_id[4]); 938 939 c->x86 = 4; 940 /* Intel-defined flags: level 0x00000001 */ 941 if (c->cpuid_level >= 0x00000001) { 942 u32 junk, tfms, cap0, misc; 943 944 cpuid(0x00000001, &tfms, &misc, &junk, &cap0); 945 c->x86 = x86_family(tfms); 946 c->x86_model = x86_model(tfms); 947 c->x86_stepping = x86_stepping(tfms); 948 949 if (cap0 & (1<<19)) { 950 c->x86_clflush_size = ((misc >> 8) & 0xff) * 8; 951 c->x86_cache_alignment = c->x86_clflush_size; 952 } 953 } 954 } 955 956 static void apply_forced_caps(struct cpuinfo_x86 *c) 957 { 958 int i; 959 960 for (i = 0; i < NCAPINTS + NBUGINTS; i++) { 961 c->x86_capability[i] &= ~cpu_caps_cleared[i]; 962 c->x86_capability[i] |= cpu_caps_set[i]; 963 } 964 } 965 966 static void init_speculation_control(struct cpuinfo_x86 *c) 967 { 968 /* 969 * The Intel SPEC_CTRL CPUID bit implies IBRS and IBPB support, 970 * and they also have a different bit for STIBP support. Also, 971 * a hypervisor might have set the individual AMD bits even on 972 * Intel CPUs, for finer-grained selection of what's available. 973 */ 974 if (cpu_has(c, X86_FEATURE_SPEC_CTRL)) { 975 set_cpu_cap(c, X86_FEATURE_IBRS); 976 set_cpu_cap(c, X86_FEATURE_IBPB); 977 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 978 } 979 980 if (cpu_has(c, X86_FEATURE_INTEL_STIBP)) 981 set_cpu_cap(c, X86_FEATURE_STIBP); 982 983 if (cpu_has(c, X86_FEATURE_SPEC_CTRL_SSBD) || 984 cpu_has(c, X86_FEATURE_VIRT_SSBD)) 985 set_cpu_cap(c, X86_FEATURE_SSBD); 986 987 if (cpu_has(c, X86_FEATURE_AMD_IBRS)) { 988 set_cpu_cap(c, X86_FEATURE_IBRS); 989 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 990 } 991 992 if (cpu_has(c, X86_FEATURE_AMD_IBPB)) 993 set_cpu_cap(c, X86_FEATURE_IBPB); 994 995 if (cpu_has(c, X86_FEATURE_AMD_STIBP)) { 996 set_cpu_cap(c, X86_FEATURE_STIBP); 997 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 998 } 999 1000 if (cpu_has(c, X86_FEATURE_AMD_SSBD)) { 1001 set_cpu_cap(c, X86_FEATURE_SSBD); 1002 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 1003 clear_cpu_cap(c, X86_FEATURE_VIRT_SSBD); 1004 } 1005 } 1006 1007 void get_cpu_cap(struct cpuinfo_x86 *c) 1008 { 1009 u32 eax, ebx, ecx, edx; 1010 1011 /* Intel-defined flags: level 0x00000001 */ 1012 if (c->cpuid_level >= 0x00000001) { 1013 cpuid(0x00000001, &eax, &ebx, &ecx, &edx); 1014 1015 c->x86_capability[CPUID_1_ECX] = ecx; 1016 c->x86_capability[CPUID_1_EDX] = edx; 1017 } 1018 1019 /* Thermal and Power Management Leaf: level 0x00000006 (eax) */ 1020 if (c->cpuid_level >= 0x00000006) 1021 c->x86_capability[CPUID_6_EAX] = cpuid_eax(0x00000006); 1022 1023 /* Additional Intel-defined flags: level 0x00000007 */ 1024 if (c->cpuid_level >= 0x00000007) { 1025 cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx); 1026 c->x86_capability[CPUID_7_0_EBX] = ebx; 1027 c->x86_capability[CPUID_7_ECX] = ecx; 1028 c->x86_capability[CPUID_7_EDX] = edx; 1029 1030 /* Check valid sub-leaf index before accessing it */ 1031 if (eax >= 1) { 1032 cpuid_count(0x00000007, 1, &eax, &ebx, &ecx, &edx); 1033 c->x86_capability[CPUID_7_1_EAX] = eax; 1034 } 1035 } 1036 1037 /* Extended state features: level 0x0000000d */ 1038 if (c->cpuid_level >= 0x0000000d) { 1039 cpuid_count(0x0000000d, 1, &eax, &ebx, &ecx, &edx); 1040 1041 c->x86_capability[CPUID_D_1_EAX] = eax; 1042 } 1043 1044 /* AMD-defined flags: level 0x80000001 */ 1045 eax = cpuid_eax(0x80000000); 1046 c->extended_cpuid_level = eax; 1047 1048 if ((eax & 0xffff0000) == 0x80000000) { 1049 if (eax >= 0x80000001) { 1050 cpuid(0x80000001, &eax, &ebx, &ecx, &edx); 1051 1052 c->x86_capability[CPUID_8000_0001_ECX] = ecx; 1053 c->x86_capability[CPUID_8000_0001_EDX] = edx; 1054 } 1055 } 1056 1057 if (c->extended_cpuid_level >= 0x80000007) { 1058 cpuid(0x80000007, &eax, &ebx, &ecx, &edx); 1059 1060 c->x86_capability[CPUID_8000_0007_EBX] = ebx; 1061 c->x86_power = edx; 1062 } 1063 1064 if (c->extended_cpuid_level >= 0x80000008) { 1065 cpuid(0x80000008, &eax, &ebx, &ecx, &edx); 1066 c->x86_capability[CPUID_8000_0008_EBX] = ebx; 1067 } 1068 1069 if (c->extended_cpuid_level >= 0x8000000a) 1070 c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a); 1071 1072 if (c->extended_cpuid_level >= 0x8000001f) 1073 c->x86_capability[CPUID_8000_001F_EAX] = cpuid_eax(0x8000001f); 1074 1075 init_scattered_cpuid_features(c); 1076 init_speculation_control(c); 1077 1078 /* 1079 * Clear/Set all flags overridden by options, after probe. 1080 * This needs to happen each time we re-probe, which may happen 1081 * several times during CPU initialization. 1082 */ 1083 apply_forced_caps(c); 1084 } 1085 1086 void get_cpu_address_sizes(struct cpuinfo_x86 *c) 1087 { 1088 u32 eax, ebx, ecx, edx; 1089 1090 if (c->extended_cpuid_level >= 0x80000008) { 1091 cpuid(0x80000008, &eax, &ebx, &ecx, &edx); 1092 1093 c->x86_virt_bits = (eax >> 8) & 0xff; 1094 c->x86_phys_bits = eax & 0xff; 1095 } 1096 #ifdef CONFIG_X86_32 1097 else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36)) 1098 c->x86_phys_bits = 36; 1099 #endif 1100 c->x86_cache_bits = c->x86_phys_bits; 1101 } 1102 1103 static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c) 1104 { 1105 #ifdef CONFIG_X86_32 1106 int i; 1107 1108 /* 1109 * First of all, decide if this is a 486 or higher 1110 * It's a 486 if we can modify the AC flag 1111 */ 1112 if (flag_is_changeable_p(X86_EFLAGS_AC)) 1113 c->x86 = 4; 1114 else 1115 c->x86 = 3; 1116 1117 for (i = 0; i < X86_VENDOR_NUM; i++) 1118 if (cpu_devs[i] && cpu_devs[i]->c_identify) { 1119 c->x86_vendor_id[0] = 0; 1120 cpu_devs[i]->c_identify(c); 1121 if (c->x86_vendor_id[0]) { 1122 get_cpu_vendor(c); 1123 break; 1124 } 1125 } 1126 #endif 1127 } 1128 1129 #define NO_SPECULATION BIT(0) 1130 #define NO_MELTDOWN BIT(1) 1131 #define NO_SSB BIT(2) 1132 #define NO_L1TF BIT(3) 1133 #define NO_MDS BIT(4) 1134 #define MSBDS_ONLY BIT(5) 1135 #define NO_SWAPGS BIT(6) 1136 #define NO_ITLB_MULTIHIT BIT(7) 1137 #define NO_SPECTRE_V2 BIT(8) 1138 #define NO_MMIO BIT(9) 1139 #define NO_EIBRS_PBRSB BIT(10) 1140 1141 #define VULNWL(vendor, family, model, whitelist) \ 1142 X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, whitelist) 1143 1144 #define VULNWL_INTEL(model, whitelist) \ 1145 VULNWL(INTEL, 6, INTEL_FAM6_##model, whitelist) 1146 1147 #define VULNWL_AMD(family, whitelist) \ 1148 VULNWL(AMD, family, X86_MODEL_ANY, whitelist) 1149 1150 #define VULNWL_HYGON(family, whitelist) \ 1151 VULNWL(HYGON, family, X86_MODEL_ANY, whitelist) 1152 1153 static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = { 1154 VULNWL(ANY, 4, X86_MODEL_ANY, NO_SPECULATION), 1155 VULNWL(CENTAUR, 5, X86_MODEL_ANY, NO_SPECULATION), 1156 VULNWL(INTEL, 5, X86_MODEL_ANY, NO_SPECULATION), 1157 VULNWL(NSC, 5, X86_MODEL_ANY, NO_SPECULATION), 1158 VULNWL(VORTEX, 5, X86_MODEL_ANY, NO_SPECULATION), 1159 VULNWL(VORTEX, 6, X86_MODEL_ANY, NO_SPECULATION), 1160 1161 /* Intel Family 6 */ 1162 VULNWL_INTEL(TIGERLAKE, NO_MMIO), 1163 VULNWL_INTEL(TIGERLAKE_L, NO_MMIO), 1164 VULNWL_INTEL(ALDERLAKE, NO_MMIO), 1165 VULNWL_INTEL(ALDERLAKE_L, NO_MMIO), 1166 1167 VULNWL_INTEL(ATOM_SALTWELL, NO_SPECULATION | NO_ITLB_MULTIHIT), 1168 VULNWL_INTEL(ATOM_SALTWELL_TABLET, NO_SPECULATION | NO_ITLB_MULTIHIT), 1169 VULNWL_INTEL(ATOM_SALTWELL_MID, NO_SPECULATION | NO_ITLB_MULTIHIT), 1170 VULNWL_INTEL(ATOM_BONNELL, NO_SPECULATION | NO_ITLB_MULTIHIT), 1171 VULNWL_INTEL(ATOM_BONNELL_MID, NO_SPECULATION | NO_ITLB_MULTIHIT), 1172 1173 VULNWL_INTEL(ATOM_SILVERMONT, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1174 VULNWL_INTEL(ATOM_SILVERMONT_D, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1175 VULNWL_INTEL(ATOM_SILVERMONT_MID, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1176 VULNWL_INTEL(ATOM_AIRMONT, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1177 VULNWL_INTEL(XEON_PHI_KNL, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1178 VULNWL_INTEL(XEON_PHI_KNM, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1179 1180 VULNWL_INTEL(CORE_YONAH, NO_SSB), 1181 1182 VULNWL_INTEL(ATOM_AIRMONT_MID, NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1183 VULNWL_INTEL(ATOM_AIRMONT_NP, NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT), 1184 1185 VULNWL_INTEL(ATOM_GOLDMONT, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1186 VULNWL_INTEL(ATOM_GOLDMONT_D, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1187 VULNWL_INTEL(ATOM_GOLDMONT_PLUS, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_EIBRS_PBRSB), 1188 1189 /* 1190 * Technically, swapgs isn't serializing on AMD (despite it previously 1191 * being documented as such in the APM). But according to AMD, %gs is 1192 * updated non-speculatively, and the issuing of %gs-relative memory 1193 * operands will be blocked until the %gs update completes, which is 1194 * good enough for our purposes. 1195 */ 1196 1197 VULNWL_INTEL(ATOM_TREMONT, NO_EIBRS_PBRSB), 1198 VULNWL_INTEL(ATOM_TREMONT_L, NO_EIBRS_PBRSB), 1199 VULNWL_INTEL(ATOM_TREMONT_D, NO_ITLB_MULTIHIT | NO_EIBRS_PBRSB), 1200 1201 /* AMD Family 0xf - 0x12 */ 1202 VULNWL_AMD(0x0f, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1203 VULNWL_AMD(0x10, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1204 VULNWL_AMD(0x11, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1205 VULNWL_AMD(0x12, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1206 1207 /* FAMILY_ANY must be last, otherwise 0x0f - 0x12 matches won't work */ 1208 VULNWL_AMD(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1209 VULNWL_HYGON(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1210 1211 /* Zhaoxin Family 7 */ 1212 VULNWL(CENTAUR, 7, X86_MODEL_ANY, NO_SPECTRE_V2 | NO_SWAPGS | NO_MMIO), 1213 VULNWL(ZHAOXIN, 7, X86_MODEL_ANY, NO_SPECTRE_V2 | NO_SWAPGS | NO_MMIO), 1214 {} 1215 }; 1216 1217 #define VULNBL(vendor, family, model, blacklist) \ 1218 X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, blacklist) 1219 1220 #define VULNBL_INTEL_STEPPINGS(model, steppings, issues) \ 1221 X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(INTEL, 6, \ 1222 INTEL_FAM6_##model, steppings, \ 1223 X86_FEATURE_ANY, issues) 1224 1225 #define VULNBL_AMD(family, blacklist) \ 1226 VULNBL(AMD, family, X86_MODEL_ANY, blacklist) 1227 1228 #define VULNBL_HYGON(family, blacklist) \ 1229 VULNBL(HYGON, family, X86_MODEL_ANY, blacklist) 1230 1231 #define SRBDS BIT(0) 1232 /* CPU is affected by X86_BUG_MMIO_STALE_DATA */ 1233 #define MMIO BIT(1) 1234 /* CPU is affected by Shared Buffers Data Sampling (SBDS), a variant of X86_BUG_MMIO_STALE_DATA */ 1235 #define MMIO_SBDS BIT(2) 1236 /* CPU is affected by RETbleed, speculating where you would not expect it */ 1237 #define RETBLEED BIT(3) 1238 1239 static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = { 1240 VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS), 1241 VULNBL_INTEL_STEPPINGS(HASWELL, X86_STEPPING_ANY, SRBDS), 1242 VULNBL_INTEL_STEPPINGS(HASWELL_L, X86_STEPPING_ANY, SRBDS), 1243 VULNBL_INTEL_STEPPINGS(HASWELL_G, X86_STEPPING_ANY, SRBDS), 1244 VULNBL_INTEL_STEPPINGS(HASWELL_X, X86_STEPPING_ANY, MMIO), 1245 VULNBL_INTEL_STEPPINGS(BROADWELL_D, X86_STEPPING_ANY, MMIO), 1246 VULNBL_INTEL_STEPPINGS(BROADWELL_G, X86_STEPPING_ANY, SRBDS), 1247 VULNBL_INTEL_STEPPINGS(BROADWELL_X, X86_STEPPING_ANY, MMIO), 1248 VULNBL_INTEL_STEPPINGS(BROADWELL, X86_STEPPING_ANY, SRBDS), 1249 VULNBL_INTEL_STEPPINGS(SKYLAKE_L, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED), 1250 VULNBL_INTEL_STEPPINGS(SKYLAKE_X, X86_STEPPING_ANY, MMIO | RETBLEED), 1251 VULNBL_INTEL_STEPPINGS(SKYLAKE, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED), 1252 VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED), 1253 VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED), 1254 VULNBL_INTEL_STEPPINGS(CANNONLAKE_L, X86_STEPPING_ANY, RETBLEED), 1255 VULNBL_INTEL_STEPPINGS(ICELAKE_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED), 1256 VULNBL_INTEL_STEPPINGS(ICELAKE_D, X86_STEPPING_ANY, MMIO), 1257 VULNBL_INTEL_STEPPINGS(ICELAKE_X, X86_STEPPING_ANY, MMIO), 1258 VULNBL_INTEL_STEPPINGS(COMETLAKE, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED), 1259 VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x0), MMIO | RETBLEED), 1260 VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED), 1261 VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED), 1262 VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPING_ANY, MMIO | RETBLEED), 1263 VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPING_ANY, MMIO | MMIO_SBDS), 1264 VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_D, X86_STEPPING_ANY, MMIO), 1265 VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS), 1266 1267 VULNBL_AMD(0x15, RETBLEED), 1268 VULNBL_AMD(0x16, RETBLEED), 1269 VULNBL_AMD(0x17, RETBLEED), 1270 VULNBL_HYGON(0x18, RETBLEED), 1271 {} 1272 }; 1273 1274 static bool __init cpu_matches(const struct x86_cpu_id *table, unsigned long which) 1275 { 1276 const struct x86_cpu_id *m = x86_match_cpu(table); 1277 1278 return m && !!(m->driver_data & which); 1279 } 1280 1281 u64 x86_read_arch_cap_msr(void) 1282 { 1283 u64 ia32_cap = 0; 1284 1285 if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES)) 1286 rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap); 1287 1288 return ia32_cap; 1289 } 1290 1291 static bool arch_cap_mmio_immune(u64 ia32_cap) 1292 { 1293 return (ia32_cap & ARCH_CAP_FBSDP_NO && 1294 ia32_cap & ARCH_CAP_PSDP_NO && 1295 ia32_cap & ARCH_CAP_SBDR_SSDP_NO); 1296 } 1297 1298 static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) 1299 { 1300 u64 ia32_cap = x86_read_arch_cap_msr(); 1301 1302 /* Set ITLB_MULTIHIT bug if cpu is not in the whitelist and not mitigated */ 1303 if (!cpu_matches(cpu_vuln_whitelist, NO_ITLB_MULTIHIT) && 1304 !(ia32_cap & ARCH_CAP_PSCHANGE_MC_NO)) 1305 setup_force_cpu_bug(X86_BUG_ITLB_MULTIHIT); 1306 1307 if (cpu_matches(cpu_vuln_whitelist, NO_SPECULATION)) 1308 return; 1309 1310 setup_force_cpu_bug(X86_BUG_SPECTRE_V1); 1311 1312 if (!cpu_matches(cpu_vuln_whitelist, NO_SPECTRE_V2)) 1313 setup_force_cpu_bug(X86_BUG_SPECTRE_V2); 1314 1315 if (!cpu_matches(cpu_vuln_whitelist, NO_SSB) && 1316 !(ia32_cap & ARCH_CAP_SSB_NO) && 1317 !cpu_has(c, X86_FEATURE_AMD_SSB_NO)) 1318 setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS); 1319 1320 if (ia32_cap & ARCH_CAP_IBRS_ALL) 1321 setup_force_cpu_cap(X86_FEATURE_IBRS_ENHANCED); 1322 1323 if (!cpu_matches(cpu_vuln_whitelist, NO_MDS) && 1324 !(ia32_cap & ARCH_CAP_MDS_NO)) { 1325 setup_force_cpu_bug(X86_BUG_MDS); 1326 if (cpu_matches(cpu_vuln_whitelist, MSBDS_ONLY)) 1327 setup_force_cpu_bug(X86_BUG_MSBDS_ONLY); 1328 } 1329 1330 if (!cpu_matches(cpu_vuln_whitelist, NO_SWAPGS)) 1331 setup_force_cpu_bug(X86_BUG_SWAPGS); 1332 1333 /* 1334 * When the CPU is not mitigated for TAA (TAA_NO=0) set TAA bug when: 1335 * - TSX is supported or 1336 * - TSX_CTRL is present 1337 * 1338 * TSX_CTRL check is needed for cases when TSX could be disabled before 1339 * the kernel boot e.g. kexec. 1340 * TSX_CTRL check alone is not sufficient for cases when the microcode 1341 * update is not present or running as guest that don't get TSX_CTRL. 1342 */ 1343 if (!(ia32_cap & ARCH_CAP_TAA_NO) && 1344 (cpu_has(c, X86_FEATURE_RTM) || 1345 (ia32_cap & ARCH_CAP_TSX_CTRL_MSR))) 1346 setup_force_cpu_bug(X86_BUG_TAA); 1347 1348 /* 1349 * SRBDS affects CPUs which support RDRAND or RDSEED and are listed 1350 * in the vulnerability blacklist. 1351 * 1352 * Some of the implications and mitigation of Shared Buffers Data 1353 * Sampling (SBDS) are similar to SRBDS. Give SBDS same treatment as 1354 * SRBDS. 1355 */ 1356 if ((cpu_has(c, X86_FEATURE_RDRAND) || 1357 cpu_has(c, X86_FEATURE_RDSEED)) && 1358 cpu_matches(cpu_vuln_blacklist, SRBDS | MMIO_SBDS)) 1359 setup_force_cpu_bug(X86_BUG_SRBDS); 1360 1361 /* 1362 * Processor MMIO Stale Data bug enumeration 1363 * 1364 * Affected CPU list is generally enough to enumerate the vulnerability, 1365 * but for virtualization case check for ARCH_CAP MSR bits also, VMM may 1366 * not want the guest to enumerate the bug. 1367 * 1368 * Set X86_BUG_MMIO_UNKNOWN for CPUs that are neither in the blacklist, 1369 * nor in the whitelist and also don't enumerate MSR ARCH_CAP MMIO bits. 1370 */ 1371 if (!arch_cap_mmio_immune(ia32_cap)) { 1372 if (cpu_matches(cpu_vuln_blacklist, MMIO)) 1373 setup_force_cpu_bug(X86_BUG_MMIO_STALE_DATA); 1374 else if (!cpu_matches(cpu_vuln_whitelist, NO_MMIO)) 1375 setup_force_cpu_bug(X86_BUG_MMIO_UNKNOWN); 1376 } 1377 1378 if (!cpu_has(c, X86_FEATURE_BTC_NO)) { 1379 if (cpu_matches(cpu_vuln_blacklist, RETBLEED) || (ia32_cap & ARCH_CAP_RSBA)) 1380 setup_force_cpu_bug(X86_BUG_RETBLEED); 1381 } 1382 1383 if (cpu_has(c, X86_FEATURE_IBRS_ENHANCED) && 1384 !cpu_matches(cpu_vuln_whitelist, NO_EIBRS_PBRSB) && 1385 !(ia32_cap & ARCH_CAP_PBRSB_NO)) 1386 setup_force_cpu_bug(X86_BUG_EIBRS_PBRSB); 1387 1388 if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN)) 1389 return; 1390 1391 /* Rogue Data Cache Load? No! */ 1392 if (ia32_cap & ARCH_CAP_RDCL_NO) 1393 return; 1394 1395 setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN); 1396 1397 if (cpu_matches(cpu_vuln_whitelist, NO_L1TF)) 1398 return; 1399 1400 setup_force_cpu_bug(X86_BUG_L1TF); 1401 } 1402 1403 /* 1404 * The NOPL instruction is supposed to exist on all CPUs of family >= 6; 1405 * unfortunately, that's not true in practice because of early VIA 1406 * chips and (more importantly) broken virtualizers that are not easy 1407 * to detect. In the latter case it doesn't even *fail* reliably, so 1408 * probing for it doesn't even work. Disable it completely on 32-bit 1409 * unless we can find a reliable way to detect all the broken cases. 1410 * Enable it explicitly on 64-bit for non-constant inputs of cpu_has(). 1411 */ 1412 static void detect_nopl(void) 1413 { 1414 #ifdef CONFIG_X86_32 1415 setup_clear_cpu_cap(X86_FEATURE_NOPL); 1416 #else 1417 setup_force_cpu_cap(X86_FEATURE_NOPL); 1418 #endif 1419 } 1420 1421 /* 1422 * We parse cpu parameters early because fpu__init_system() is executed 1423 * before parse_early_param(). 1424 */ 1425 static void __init cpu_parse_early_param(void) 1426 { 1427 char arg[128]; 1428 char *argptr = arg, *opt; 1429 int arglen, taint = 0; 1430 1431 #ifdef CONFIG_X86_32 1432 if (cmdline_find_option_bool(boot_command_line, "no387")) 1433 #ifdef CONFIG_MATH_EMULATION 1434 setup_clear_cpu_cap(X86_FEATURE_FPU); 1435 #else 1436 pr_err("Option 'no387' required CONFIG_MATH_EMULATION enabled.\n"); 1437 #endif 1438 1439 if (cmdline_find_option_bool(boot_command_line, "nofxsr")) 1440 setup_clear_cpu_cap(X86_FEATURE_FXSR); 1441 #endif 1442 1443 if (cmdline_find_option_bool(boot_command_line, "noxsave")) 1444 setup_clear_cpu_cap(X86_FEATURE_XSAVE); 1445 1446 if (cmdline_find_option_bool(boot_command_line, "noxsaveopt")) 1447 setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT); 1448 1449 if (cmdline_find_option_bool(boot_command_line, "noxsaves")) 1450 setup_clear_cpu_cap(X86_FEATURE_XSAVES); 1451 1452 arglen = cmdline_find_option(boot_command_line, "clearcpuid", arg, sizeof(arg)); 1453 if (arglen <= 0) 1454 return; 1455 1456 pr_info("Clearing CPUID bits:"); 1457 1458 while (argptr) { 1459 bool found __maybe_unused = false; 1460 unsigned int bit; 1461 1462 opt = strsep(&argptr, ","); 1463 1464 /* 1465 * Handle naked numbers first for feature flags which don't 1466 * have names. 1467 */ 1468 if (!kstrtouint(opt, 10, &bit)) { 1469 if (bit < NCAPINTS * 32) { 1470 1471 #ifdef CONFIG_X86_FEATURE_NAMES 1472 /* empty-string, i.e., ""-defined feature flags */ 1473 if (!x86_cap_flags[bit]) 1474 pr_cont(" " X86_CAP_FMT_NUM, x86_cap_flag_num(bit)); 1475 else 1476 #endif 1477 pr_cont(" " X86_CAP_FMT, x86_cap_flag(bit)); 1478 1479 setup_clear_cpu_cap(bit); 1480 taint++; 1481 } 1482 /* 1483 * The assumption is that there are no feature names with only 1484 * numbers in the name thus go to the next argument. 1485 */ 1486 continue; 1487 } 1488 1489 #ifdef CONFIG_X86_FEATURE_NAMES 1490 for (bit = 0; bit < 32 * NCAPINTS; bit++) { 1491 if (!x86_cap_flag(bit)) 1492 continue; 1493 1494 if (strcmp(x86_cap_flag(bit), opt)) 1495 continue; 1496 1497 pr_cont(" %s", opt); 1498 setup_clear_cpu_cap(bit); 1499 taint++; 1500 found = true; 1501 break; 1502 } 1503 1504 if (!found) 1505 pr_cont(" (unknown: %s)", opt); 1506 #endif 1507 } 1508 pr_cont("\n"); 1509 1510 if (taint) 1511 add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); 1512 } 1513 1514 /* 1515 * Do minimum CPU detection early. 1516 * Fields really needed: vendor, cpuid_level, family, model, mask, 1517 * cache alignment. 1518 * The others are not touched to avoid unwanted side effects. 1519 * 1520 * WARNING: this function is only called on the boot CPU. Don't add code 1521 * here that is supposed to run on all CPUs. 1522 */ 1523 static void __init early_identify_cpu(struct cpuinfo_x86 *c) 1524 { 1525 #ifdef CONFIG_X86_64 1526 c->x86_clflush_size = 64; 1527 c->x86_phys_bits = 36; 1528 c->x86_virt_bits = 48; 1529 #else 1530 c->x86_clflush_size = 32; 1531 c->x86_phys_bits = 32; 1532 c->x86_virt_bits = 32; 1533 #endif 1534 c->x86_cache_alignment = c->x86_clflush_size; 1535 1536 memset(&c->x86_capability, 0, sizeof(c->x86_capability)); 1537 c->extended_cpuid_level = 0; 1538 1539 if (!have_cpuid_p()) 1540 identify_cpu_without_cpuid(c); 1541 1542 /* cyrix could have cpuid enabled via c_identify()*/ 1543 if (have_cpuid_p()) { 1544 cpu_detect(c); 1545 get_cpu_vendor(c); 1546 get_cpu_cap(c); 1547 get_cpu_address_sizes(c); 1548 setup_force_cpu_cap(X86_FEATURE_CPUID); 1549 cpu_parse_early_param(); 1550 1551 if (this_cpu->c_early_init) 1552 this_cpu->c_early_init(c); 1553 1554 c->cpu_index = 0; 1555 filter_cpuid_features(c, false); 1556 1557 if (this_cpu->c_bsp_init) 1558 this_cpu->c_bsp_init(c); 1559 } else { 1560 setup_clear_cpu_cap(X86_FEATURE_CPUID); 1561 } 1562 1563 setup_force_cpu_cap(X86_FEATURE_ALWAYS); 1564 1565 cpu_set_bug_bits(c); 1566 1567 sld_setup(c); 1568 1569 fpu__init_system(c); 1570 1571 init_sigframe_size(); 1572 1573 #ifdef CONFIG_X86_32 1574 /* 1575 * Regardless of whether PCID is enumerated, the SDM says 1576 * that it can't be enabled in 32-bit mode. 1577 */ 1578 setup_clear_cpu_cap(X86_FEATURE_PCID); 1579 #endif 1580 1581 /* 1582 * Later in the boot process pgtable_l5_enabled() relies on 1583 * cpu_feature_enabled(X86_FEATURE_LA57). If 5-level paging is not 1584 * enabled by this point we need to clear the feature bit to avoid 1585 * false-positives at the later stage. 1586 * 1587 * pgtable_l5_enabled() can be false here for several reasons: 1588 * - 5-level paging is disabled compile-time; 1589 * - it's 32-bit kernel; 1590 * - machine doesn't support 5-level paging; 1591 * - user specified 'no5lvl' in kernel command line. 1592 */ 1593 if (!pgtable_l5_enabled()) 1594 setup_clear_cpu_cap(X86_FEATURE_LA57); 1595 1596 detect_nopl(); 1597 } 1598 1599 void __init early_cpu_init(void) 1600 { 1601 const struct cpu_dev *const *cdev; 1602 int count = 0; 1603 1604 #ifdef CONFIG_PROCESSOR_SELECT 1605 pr_info("KERNEL supported cpus:\n"); 1606 #endif 1607 1608 for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) { 1609 const struct cpu_dev *cpudev = *cdev; 1610 1611 if (count >= X86_VENDOR_NUM) 1612 break; 1613 cpu_devs[count] = cpudev; 1614 count++; 1615 1616 #ifdef CONFIG_PROCESSOR_SELECT 1617 { 1618 unsigned int j; 1619 1620 for (j = 0; j < 2; j++) { 1621 if (!cpudev->c_ident[j]) 1622 continue; 1623 pr_info(" %s %s\n", cpudev->c_vendor, 1624 cpudev->c_ident[j]); 1625 } 1626 } 1627 #endif 1628 } 1629 early_identify_cpu(&boot_cpu_data); 1630 } 1631 1632 static bool detect_null_seg_behavior(void) 1633 { 1634 /* 1635 * Empirically, writing zero to a segment selector on AMD does 1636 * not clear the base, whereas writing zero to a segment 1637 * selector on Intel does clear the base. Intel's behavior 1638 * allows slightly faster context switches in the common case 1639 * where GS is unused by the prev and next threads. 1640 * 1641 * Since neither vendor documents this anywhere that I can see, 1642 * detect it directly instead of hard-coding the choice by 1643 * vendor. 1644 * 1645 * I've designated AMD's behavior as the "bug" because it's 1646 * counterintuitive and less friendly. 1647 */ 1648 1649 unsigned long old_base, tmp; 1650 rdmsrl(MSR_FS_BASE, old_base); 1651 wrmsrl(MSR_FS_BASE, 1); 1652 loadsegment(fs, 0); 1653 rdmsrl(MSR_FS_BASE, tmp); 1654 wrmsrl(MSR_FS_BASE, old_base); 1655 return tmp == 0; 1656 } 1657 1658 void check_null_seg_clears_base(struct cpuinfo_x86 *c) 1659 { 1660 /* BUG_NULL_SEG is only relevant with 64bit userspace */ 1661 if (!IS_ENABLED(CONFIG_X86_64)) 1662 return; 1663 1664 /* Zen3 CPUs advertise Null Selector Clears Base in CPUID. */ 1665 if (c->extended_cpuid_level >= 0x80000021 && 1666 cpuid_eax(0x80000021) & BIT(6)) 1667 return; 1668 1669 /* 1670 * CPUID bit above wasn't set. If this kernel is still running 1671 * as a HV guest, then the HV has decided not to advertize 1672 * that CPUID bit for whatever reason. For example, one 1673 * member of the migration pool might be vulnerable. Which 1674 * means, the bug is present: set the BUG flag and return. 1675 */ 1676 if (cpu_has(c, X86_FEATURE_HYPERVISOR)) { 1677 set_cpu_bug(c, X86_BUG_NULL_SEG); 1678 return; 1679 } 1680 1681 /* 1682 * Zen2 CPUs also have this behaviour, but no CPUID bit. 1683 * 0x18 is the respective family for Hygon. 1684 */ 1685 if ((c->x86 == 0x17 || c->x86 == 0x18) && 1686 detect_null_seg_behavior()) 1687 return; 1688 1689 /* All the remaining ones are affected */ 1690 set_cpu_bug(c, X86_BUG_NULL_SEG); 1691 } 1692 1693 static void generic_identify(struct cpuinfo_x86 *c) 1694 { 1695 c->extended_cpuid_level = 0; 1696 1697 if (!have_cpuid_p()) 1698 identify_cpu_without_cpuid(c); 1699 1700 /* cyrix could have cpuid enabled via c_identify()*/ 1701 if (!have_cpuid_p()) 1702 return; 1703 1704 cpu_detect(c); 1705 1706 get_cpu_vendor(c); 1707 1708 get_cpu_cap(c); 1709 1710 get_cpu_address_sizes(c); 1711 1712 if (c->cpuid_level >= 0x00000001) { 1713 c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xFF; 1714 #ifdef CONFIG_X86_32 1715 # ifdef CONFIG_SMP 1716 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0); 1717 # else 1718 c->apicid = c->initial_apicid; 1719 # endif 1720 #endif 1721 c->phys_proc_id = c->initial_apicid; 1722 } 1723 1724 get_model_name(c); /* Default name */ 1725 1726 /* 1727 * ESPFIX is a strange bug. All real CPUs have it. Paravirt 1728 * systems that run Linux at CPL > 0 may or may not have the 1729 * issue, but, even if they have the issue, there's absolutely 1730 * nothing we can do about it because we can't use the real IRET 1731 * instruction. 1732 * 1733 * NB: For the time being, only 32-bit kernels support 1734 * X86_BUG_ESPFIX as such. 64-bit kernels directly choose 1735 * whether to apply espfix using paravirt hooks. If any 1736 * non-paravirt system ever shows up that does *not* have the 1737 * ESPFIX issue, we can change this. 1738 */ 1739 #ifdef CONFIG_X86_32 1740 set_cpu_bug(c, X86_BUG_ESPFIX); 1741 #endif 1742 } 1743 1744 /* 1745 * Validate that ACPI/mptables have the same information about the 1746 * effective APIC id and update the package map. 1747 */ 1748 static void validate_apic_and_package_id(struct cpuinfo_x86 *c) 1749 { 1750 #ifdef CONFIG_SMP 1751 unsigned int apicid, cpu = smp_processor_id(); 1752 1753 apicid = apic->cpu_present_to_apicid(cpu); 1754 1755 if (apicid != c->apicid) { 1756 pr_err(FW_BUG "CPU%u: APIC id mismatch. Firmware: %x APIC: %x\n", 1757 cpu, apicid, c->initial_apicid); 1758 } 1759 BUG_ON(topology_update_package_map(c->phys_proc_id, cpu)); 1760 BUG_ON(topology_update_die_map(c->cpu_die_id, cpu)); 1761 #else 1762 c->logical_proc_id = 0; 1763 #endif 1764 } 1765 1766 /* 1767 * This does the hard work of actually picking apart the CPU stuff... 1768 */ 1769 static void identify_cpu(struct cpuinfo_x86 *c) 1770 { 1771 int i; 1772 1773 c->loops_per_jiffy = loops_per_jiffy; 1774 c->x86_cache_size = 0; 1775 c->x86_vendor = X86_VENDOR_UNKNOWN; 1776 c->x86_model = c->x86_stepping = 0; /* So far unknown... */ 1777 c->x86_vendor_id[0] = '\0'; /* Unset */ 1778 c->x86_model_id[0] = '\0'; /* Unset */ 1779 c->x86_max_cores = 1; 1780 c->x86_coreid_bits = 0; 1781 c->cu_id = 0xff; 1782 #ifdef CONFIG_X86_64 1783 c->x86_clflush_size = 64; 1784 c->x86_phys_bits = 36; 1785 c->x86_virt_bits = 48; 1786 #else 1787 c->cpuid_level = -1; /* CPUID not detected */ 1788 c->x86_clflush_size = 32; 1789 c->x86_phys_bits = 32; 1790 c->x86_virt_bits = 32; 1791 #endif 1792 c->x86_cache_alignment = c->x86_clflush_size; 1793 memset(&c->x86_capability, 0, sizeof(c->x86_capability)); 1794 #ifdef CONFIG_X86_VMX_FEATURE_NAMES 1795 memset(&c->vmx_capability, 0, sizeof(c->vmx_capability)); 1796 #endif 1797 1798 generic_identify(c); 1799 1800 if (this_cpu->c_identify) 1801 this_cpu->c_identify(c); 1802 1803 /* Clear/Set all flags overridden by options, after probe */ 1804 apply_forced_caps(c); 1805 1806 #ifdef CONFIG_X86_64 1807 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0); 1808 #endif 1809 1810 /* 1811 * Vendor-specific initialization. In this section we 1812 * canonicalize the feature flags, meaning if there are 1813 * features a certain CPU supports which CPUID doesn't 1814 * tell us, CPUID claiming incorrect flags, or other bugs, 1815 * we handle them here. 1816 * 1817 * At the end of this section, c->x86_capability better 1818 * indicate the features this CPU genuinely supports! 1819 */ 1820 if (this_cpu->c_init) 1821 this_cpu->c_init(c); 1822 1823 /* Disable the PN if appropriate */ 1824 squash_the_stupid_serial_number(c); 1825 1826 /* Set up SMEP/SMAP/UMIP */ 1827 setup_smep(c); 1828 setup_smap(c); 1829 setup_umip(c); 1830 1831 /* Enable FSGSBASE instructions if available. */ 1832 if (cpu_has(c, X86_FEATURE_FSGSBASE)) { 1833 cr4_set_bits(X86_CR4_FSGSBASE); 1834 elf_hwcap2 |= HWCAP2_FSGSBASE; 1835 } 1836 1837 /* 1838 * The vendor-specific functions might have changed features. 1839 * Now we do "generic changes." 1840 */ 1841 1842 /* Filter out anything that depends on CPUID levels we don't have */ 1843 filter_cpuid_features(c, true); 1844 1845 /* If the model name is still unset, do table lookup. */ 1846 if (!c->x86_model_id[0]) { 1847 const char *p; 1848 p = table_lookup_model(c); 1849 if (p) 1850 strcpy(c->x86_model_id, p); 1851 else 1852 /* Last resort... */ 1853 sprintf(c->x86_model_id, "%02x/%02x", 1854 c->x86, c->x86_model); 1855 } 1856 1857 #ifdef CONFIG_X86_64 1858 detect_ht(c); 1859 #endif 1860 1861 x86_init_rdrand(c); 1862 setup_pku(c); 1863 setup_cet(c); 1864 1865 /* 1866 * Clear/Set all flags overridden by options, need do it 1867 * before following smp all cpus cap AND. 1868 */ 1869 apply_forced_caps(c); 1870 1871 /* 1872 * On SMP, boot_cpu_data holds the common feature set between 1873 * all CPUs; so make sure that we indicate which features are 1874 * common between the CPUs. The first time this routine gets 1875 * executed, c == &boot_cpu_data. 1876 */ 1877 if (c != &boot_cpu_data) { 1878 /* AND the already accumulated flags with these */ 1879 for (i = 0; i < NCAPINTS; i++) 1880 boot_cpu_data.x86_capability[i] &= c->x86_capability[i]; 1881 1882 /* OR, i.e. replicate the bug flags */ 1883 for (i = NCAPINTS; i < NCAPINTS + NBUGINTS; i++) 1884 c->x86_capability[i] |= boot_cpu_data.x86_capability[i]; 1885 } 1886 1887 ppin_init(c); 1888 1889 /* Init Machine Check Exception if available. */ 1890 mcheck_cpu_init(c); 1891 1892 select_idle_routine(c); 1893 1894 #ifdef CONFIG_NUMA 1895 numa_add_cpu(smp_processor_id()); 1896 #endif 1897 } 1898 1899 /* 1900 * Set up the CPU state needed to execute SYSENTER/SYSEXIT instructions 1901 * on 32-bit kernels: 1902 */ 1903 #ifdef CONFIG_X86_32 1904 void enable_sep_cpu(void) 1905 { 1906 struct tss_struct *tss; 1907 int cpu; 1908 1909 if (!boot_cpu_has(X86_FEATURE_SEP)) 1910 return; 1911 1912 cpu = get_cpu(); 1913 tss = &per_cpu(cpu_tss_rw, cpu); 1914 1915 /* 1916 * We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field -- 1917 * see the big comment in struct x86_hw_tss's definition. 1918 */ 1919 1920 tss->x86_tss.ss1 = __KERNEL_CS; 1921 wrmsr(MSR_IA32_SYSENTER_CS, tss->x86_tss.ss1, 0); 1922 wrmsr(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_entry_stack(cpu) + 1), 0); 1923 wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0); 1924 1925 put_cpu(); 1926 } 1927 #endif 1928 1929 void __init identify_boot_cpu(void) 1930 { 1931 identify_cpu(&boot_cpu_data); 1932 if (HAS_KERNEL_IBT && cpu_feature_enabled(X86_FEATURE_IBT)) 1933 pr_info("CET detected: Indirect Branch Tracking enabled\n"); 1934 #ifdef CONFIG_X86_32 1935 sysenter_setup(); 1936 enable_sep_cpu(); 1937 #endif 1938 cpu_detect_tlb(&boot_cpu_data); 1939 setup_cr_pinning(); 1940 1941 tsx_init(); 1942 } 1943 1944 void identify_secondary_cpu(struct cpuinfo_x86 *c) 1945 { 1946 BUG_ON(c == &boot_cpu_data); 1947 identify_cpu(c); 1948 #ifdef CONFIG_X86_32 1949 enable_sep_cpu(); 1950 #endif 1951 mtrr_ap_init(); 1952 validate_apic_and_package_id(c); 1953 x86_spec_ctrl_setup_ap(); 1954 update_srbds_msr(); 1955 1956 tsx_ap_init(); 1957 } 1958 1959 void print_cpu_info(struct cpuinfo_x86 *c) 1960 { 1961 const char *vendor = NULL; 1962 1963 if (c->x86_vendor < X86_VENDOR_NUM) { 1964 vendor = this_cpu->c_vendor; 1965 } else { 1966 if (c->cpuid_level >= 0) 1967 vendor = c->x86_vendor_id; 1968 } 1969 1970 if (vendor && !strstr(c->x86_model_id, vendor)) 1971 pr_cont("%s ", vendor); 1972 1973 if (c->x86_model_id[0]) 1974 pr_cont("%s", c->x86_model_id); 1975 else 1976 pr_cont("%d86", c->x86); 1977 1978 pr_cont(" (family: 0x%x, model: 0x%x", c->x86, c->x86_model); 1979 1980 if (c->x86_stepping || c->cpuid_level >= 0) 1981 pr_cont(", stepping: 0x%x)\n", c->x86_stepping); 1982 else 1983 pr_cont(")\n"); 1984 } 1985 1986 /* 1987 * clearcpuid= was already parsed in cpu_parse_early_param(). This dummy 1988 * function prevents it from becoming an environment variable for init. 1989 */ 1990 static __init int setup_clearcpuid(char *arg) 1991 { 1992 return 1; 1993 } 1994 __setup("clearcpuid=", setup_clearcpuid); 1995 1996 #ifdef CONFIG_X86_64 1997 DEFINE_PER_CPU_FIRST(struct fixed_percpu_data, 1998 fixed_percpu_data) __aligned(PAGE_SIZE) __visible; 1999 EXPORT_PER_CPU_SYMBOL_GPL(fixed_percpu_data); 2000 2001 /* 2002 * The following percpu variables are hot. Align current_task to 2003 * cacheline size such that they fall in the same cacheline. 2004 */ 2005 DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned = 2006 &init_task; 2007 EXPORT_PER_CPU_SYMBOL(current_task); 2008 2009 DEFINE_PER_CPU(void *, hardirq_stack_ptr); 2010 DEFINE_PER_CPU(bool, hardirq_stack_inuse); 2011 2012 DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT; 2013 EXPORT_PER_CPU_SYMBOL(__preempt_count); 2014 2015 DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack) = TOP_OF_INIT_STACK; 2016 2017 static void wrmsrl_cstar(unsigned long val) 2018 { 2019 /* 2020 * Intel CPUs do not support 32-bit SYSCALL. Writing to MSR_CSTAR 2021 * is so far ignored by the CPU, but raises a #VE trap in a TDX 2022 * guest. Avoid the pointless write on all Intel CPUs. 2023 */ 2024 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) 2025 wrmsrl(MSR_CSTAR, val); 2026 } 2027 2028 /* May not be marked __init: used by software suspend */ 2029 void syscall_init(void) 2030 { 2031 wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS); 2032 wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64); 2033 2034 #ifdef CONFIG_IA32_EMULATION 2035 wrmsrl_cstar((unsigned long)entry_SYSCALL_compat); 2036 /* 2037 * This only works on Intel CPUs. 2038 * On AMD CPUs these MSRs are 32-bit, CPU truncates MSR_IA32_SYSENTER_EIP. 2039 * This does not cause SYSENTER to jump to the wrong location, because 2040 * AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit). 2041 */ 2042 wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS); 2043 wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 2044 (unsigned long)(cpu_entry_stack(smp_processor_id()) + 1)); 2045 wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat); 2046 #else 2047 wrmsrl_cstar((unsigned long)ignore_sysret); 2048 wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG); 2049 wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL); 2050 wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL); 2051 #endif 2052 2053 /* 2054 * Flags to clear on syscall; clear as much as possible 2055 * to minimize user space-kernel interference. 2056 */ 2057 wrmsrl(MSR_SYSCALL_MASK, 2058 X86_EFLAGS_CF|X86_EFLAGS_PF|X86_EFLAGS_AF| 2059 X86_EFLAGS_ZF|X86_EFLAGS_SF|X86_EFLAGS_TF| 2060 X86_EFLAGS_IF|X86_EFLAGS_DF|X86_EFLAGS_OF| 2061 X86_EFLAGS_IOPL|X86_EFLAGS_NT|X86_EFLAGS_RF| 2062 X86_EFLAGS_AC|X86_EFLAGS_ID); 2063 } 2064 2065 #else /* CONFIG_X86_64 */ 2066 2067 DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task; 2068 EXPORT_PER_CPU_SYMBOL(current_task); 2069 DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT; 2070 EXPORT_PER_CPU_SYMBOL(__preempt_count); 2071 2072 /* 2073 * On x86_32, vm86 modifies tss.sp0, so sp0 isn't a reliable way to find 2074 * the top of the kernel stack. Use an extra percpu variable to track the 2075 * top of the kernel stack directly. 2076 */ 2077 DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack) = 2078 (unsigned long)&init_thread_union + THREAD_SIZE; 2079 EXPORT_PER_CPU_SYMBOL(cpu_current_top_of_stack); 2080 2081 #ifdef CONFIG_STACKPROTECTOR 2082 DEFINE_PER_CPU(unsigned long, __stack_chk_guard); 2083 EXPORT_PER_CPU_SYMBOL(__stack_chk_guard); 2084 #endif 2085 2086 #endif /* CONFIG_X86_64 */ 2087 2088 /* 2089 * Clear all 6 debug registers: 2090 */ 2091 static void clear_all_debug_regs(void) 2092 { 2093 int i; 2094 2095 for (i = 0; i < 8; i++) { 2096 /* Ignore db4, db5 */ 2097 if ((i == 4) || (i == 5)) 2098 continue; 2099 2100 set_debugreg(0, i); 2101 } 2102 } 2103 2104 #ifdef CONFIG_KGDB 2105 /* 2106 * Restore debug regs if using kgdbwait and you have a kernel debugger 2107 * connection established. 2108 */ 2109 static void dbg_restore_debug_regs(void) 2110 { 2111 if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break)) 2112 arch_kgdb_ops.correct_hw_break(); 2113 } 2114 #else /* ! CONFIG_KGDB */ 2115 #define dbg_restore_debug_regs() 2116 #endif /* ! CONFIG_KGDB */ 2117 2118 static void wait_for_master_cpu(int cpu) 2119 { 2120 #ifdef CONFIG_SMP 2121 /* 2122 * wait for ACK from master CPU before continuing 2123 * with AP initialization 2124 */ 2125 WARN_ON(cpumask_test_and_set_cpu(cpu, cpu_initialized_mask)); 2126 while (!cpumask_test_cpu(cpu, cpu_callout_mask)) 2127 cpu_relax(); 2128 #endif 2129 } 2130 2131 #ifdef CONFIG_X86_64 2132 static inline void setup_getcpu(int cpu) 2133 { 2134 unsigned long cpudata = vdso_encode_cpunode(cpu, early_cpu_to_node(cpu)); 2135 struct desc_struct d = { }; 2136 2137 if (boot_cpu_has(X86_FEATURE_RDTSCP) || boot_cpu_has(X86_FEATURE_RDPID)) 2138 wrmsr(MSR_TSC_AUX, cpudata, 0); 2139 2140 /* Store CPU and node number in limit. */ 2141 d.limit0 = cpudata; 2142 d.limit1 = cpudata >> 16; 2143 2144 d.type = 5; /* RO data, expand down, accessed */ 2145 d.dpl = 3; /* Visible to user code */ 2146 d.s = 1; /* Not a system segment */ 2147 d.p = 1; /* Present */ 2148 d.d = 1; /* 32-bit */ 2149 2150 write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_CPUNODE, &d, DESCTYPE_S); 2151 } 2152 2153 static inline void ucode_cpu_init(int cpu) 2154 { 2155 if (cpu) 2156 load_ucode_ap(); 2157 } 2158 2159 static inline void tss_setup_ist(struct tss_struct *tss) 2160 { 2161 /* Set up the per-CPU TSS IST stacks */ 2162 tss->x86_tss.ist[IST_INDEX_DF] = __this_cpu_ist_top_va(DF); 2163 tss->x86_tss.ist[IST_INDEX_NMI] = __this_cpu_ist_top_va(NMI); 2164 tss->x86_tss.ist[IST_INDEX_DB] = __this_cpu_ist_top_va(DB); 2165 tss->x86_tss.ist[IST_INDEX_MCE] = __this_cpu_ist_top_va(MCE); 2166 /* Only mapped when SEV-ES is active */ 2167 tss->x86_tss.ist[IST_INDEX_VC] = __this_cpu_ist_top_va(VC); 2168 } 2169 2170 #else /* CONFIG_X86_64 */ 2171 2172 static inline void setup_getcpu(int cpu) { } 2173 2174 static inline void ucode_cpu_init(int cpu) 2175 { 2176 show_ucode_info_early(); 2177 } 2178 2179 static inline void tss_setup_ist(struct tss_struct *tss) { } 2180 2181 #endif /* !CONFIG_X86_64 */ 2182 2183 static inline void tss_setup_io_bitmap(struct tss_struct *tss) 2184 { 2185 tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID; 2186 2187 #ifdef CONFIG_X86_IOPL_IOPERM 2188 tss->io_bitmap.prev_max = 0; 2189 tss->io_bitmap.prev_sequence = 0; 2190 memset(tss->io_bitmap.bitmap, 0xff, sizeof(tss->io_bitmap.bitmap)); 2191 /* 2192 * Invalidate the extra array entry past the end of the all 2193 * permission bitmap as required by the hardware. 2194 */ 2195 tss->io_bitmap.mapall[IO_BITMAP_LONGS] = ~0UL; 2196 #endif 2197 } 2198 2199 /* 2200 * Setup everything needed to handle exceptions from the IDT, including the IST 2201 * exceptions which use paranoid_entry(). 2202 */ 2203 void cpu_init_exception_handling(void) 2204 { 2205 struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw); 2206 int cpu = raw_smp_processor_id(); 2207 2208 /* paranoid_entry() gets the CPU number from the GDT */ 2209 setup_getcpu(cpu); 2210 2211 /* IST vectors need TSS to be set up. */ 2212 tss_setup_ist(tss); 2213 tss_setup_io_bitmap(tss); 2214 set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); 2215 2216 load_TR_desc(); 2217 2218 /* GHCB needs to be setup to handle #VC. */ 2219 setup_ghcb(); 2220 2221 /* Finally load the IDT */ 2222 load_current_idt(); 2223 } 2224 2225 /* 2226 * cpu_init() initializes state that is per-CPU. Some data is already 2227 * initialized (naturally) in the bootstrap process, such as the GDT. We 2228 * reload it nevertheless, this function acts as a 'CPU state barrier', 2229 * nothing should get across. 2230 */ 2231 void cpu_init(void) 2232 { 2233 struct task_struct *cur = current; 2234 int cpu = raw_smp_processor_id(); 2235 2236 wait_for_master_cpu(cpu); 2237 2238 ucode_cpu_init(cpu); 2239 2240 #ifdef CONFIG_NUMA 2241 if (this_cpu_read(numa_node) == 0 && 2242 early_cpu_to_node(cpu) != NUMA_NO_NODE) 2243 set_numa_node(early_cpu_to_node(cpu)); 2244 #endif 2245 pr_debug("Initializing CPU#%d\n", cpu); 2246 2247 if (IS_ENABLED(CONFIG_X86_64) || cpu_feature_enabled(X86_FEATURE_VME) || 2248 boot_cpu_has(X86_FEATURE_TSC) || boot_cpu_has(X86_FEATURE_DE)) 2249 cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE); 2250 2251 /* 2252 * Initialize the per-CPU GDT with the boot GDT, 2253 * and set up the GDT descriptor: 2254 */ 2255 switch_to_new_gdt(cpu); 2256 2257 if (IS_ENABLED(CONFIG_X86_64)) { 2258 loadsegment(fs, 0); 2259 memset(cur->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8); 2260 syscall_init(); 2261 2262 wrmsrl(MSR_FS_BASE, 0); 2263 wrmsrl(MSR_KERNEL_GS_BASE, 0); 2264 barrier(); 2265 2266 x2apic_setup(); 2267 } 2268 2269 mmgrab(&init_mm); 2270 cur->active_mm = &init_mm; 2271 BUG_ON(cur->mm); 2272 initialize_tlbstate_and_flush(); 2273 enter_lazy_tlb(&init_mm, cur); 2274 2275 /* 2276 * sp0 points to the entry trampoline stack regardless of what task 2277 * is running. 2278 */ 2279 load_sp0((unsigned long)(cpu_entry_stack(cpu) + 1)); 2280 2281 load_mm_ldt(&init_mm); 2282 2283 clear_all_debug_regs(); 2284 dbg_restore_debug_regs(); 2285 2286 doublefault_init_cpu_tss(); 2287 2288 fpu__init_cpu(); 2289 2290 if (is_uv_system()) 2291 uv_cpu_init(); 2292 2293 load_fixmap_gdt(cpu); 2294 } 2295 2296 #ifdef CONFIG_SMP 2297 void cpu_init_secondary(void) 2298 { 2299 /* 2300 * Relies on the BP having set-up the IDT tables, which are loaded 2301 * on this CPU in cpu_init_exception_handling(). 2302 */ 2303 cpu_init_exception_handling(); 2304 cpu_init(); 2305 } 2306 #endif 2307 2308 #ifdef CONFIG_MICROCODE_LATE_LOADING 2309 /* 2310 * The microcode loader calls this upon late microcode load to recheck features, 2311 * only when microcode has been updated. Caller holds microcode_mutex and CPU 2312 * hotplug lock. 2313 */ 2314 void microcode_check(void) 2315 { 2316 struct cpuinfo_x86 info; 2317 2318 perf_check_microcode(); 2319 2320 /* Reload CPUID max function as it might've changed. */ 2321 info.cpuid_level = cpuid_eax(0); 2322 2323 /* 2324 * Copy all capability leafs to pick up the synthetic ones so that 2325 * memcmp() below doesn't fail on that. The ones coming from CPUID will 2326 * get overwritten in get_cpu_cap(). 2327 */ 2328 memcpy(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability)); 2329 2330 get_cpu_cap(&info); 2331 2332 if (!memcmp(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability))) 2333 return; 2334 2335 pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n"); 2336 pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n"); 2337 } 2338 #endif 2339 2340 /* 2341 * Invoked from core CPU hotplug code after hotplug operations 2342 */ 2343 void arch_smt_update(void) 2344 { 2345 /* Handle the speculative execution misfeatures */ 2346 cpu_bugs_smt_update(); 2347 /* Check whether IPI broadcasting can be enabled */ 2348 apic_smt_update(); 2349 } 2350