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/cpuid.h> 33 #include <asm/perf_event.h> 34 #include <asm/mmu_context.h> 35 #include <asm/doublefault.h> 36 #include <asm/archrandom.h> 37 #include <asm/hypervisor.h> 38 #include <asm/processor.h> 39 #include <asm/tlbflush.h> 40 #include <asm/debugreg.h> 41 #include <asm/sections.h> 42 #include <asm/vsyscall.h> 43 #include <linux/topology.h> 44 #include <linux/cpumask.h> 45 #include <linux/atomic.h> 46 #include <asm/proto.h> 47 #include <asm/setup.h> 48 #include <asm/apic.h> 49 #include <asm/desc.h> 50 #include <asm/fpu/api.h> 51 #include <asm/mtrr.h> 52 #include <asm/hwcap2.h> 53 #include <linux/numa.h> 54 #include <asm/numa.h> 55 #include <asm/asm.h> 56 #include <asm/bugs.h> 57 #include <asm/cpu.h> 58 #include <asm/mce.h> 59 #include <asm/msr.h> 60 #include <asm/cacheinfo.h> 61 #include <asm/memtype.h> 62 #include <asm/microcode.h> 63 #include <asm/intel-family.h> 64 #include <asm/cpu_device_id.h> 65 #include <asm/fred.h> 66 #include <asm/uv/uv.h> 67 #include <asm/ia32.h> 68 #include <asm/set_memory.h> 69 #include <asm/traps.h> 70 #include <asm/sev.h> 71 #include <asm/tdx.h> 72 #include <asm/posted_intr.h> 73 #include <asm/runtime-const.h> 74 75 #include "cpu.h" 76 77 DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info); 78 EXPORT_PER_CPU_SYMBOL(cpu_info); 79 80 u32 elf_hwcap2 __read_mostly; 81 82 /* Number of siblings per CPU package */ 83 unsigned int __max_threads_per_core __ro_after_init = 1; 84 EXPORT_SYMBOL(__max_threads_per_core); 85 86 unsigned int __max_dies_per_package __ro_after_init = 1; 87 EXPORT_SYMBOL(__max_dies_per_package); 88 89 unsigned int __max_logical_packages __ro_after_init = 1; 90 EXPORT_SYMBOL(__max_logical_packages); 91 92 unsigned int __num_cores_per_package __ro_after_init = 1; 93 EXPORT_SYMBOL(__num_cores_per_package); 94 95 unsigned int __num_threads_per_package __ro_after_init = 1; 96 EXPORT_SYMBOL(__num_threads_per_package); 97 98 static struct ppin_info { 99 int feature; 100 int msr_ppin_ctl; 101 int msr_ppin; 102 } ppin_info[] = { 103 [X86_VENDOR_INTEL] = { 104 .feature = X86_FEATURE_INTEL_PPIN, 105 .msr_ppin_ctl = MSR_PPIN_CTL, 106 .msr_ppin = MSR_PPIN 107 }, 108 [X86_VENDOR_AMD] = { 109 .feature = X86_FEATURE_AMD_PPIN, 110 .msr_ppin_ctl = MSR_AMD_PPIN_CTL, 111 .msr_ppin = MSR_AMD_PPIN 112 }, 113 }; 114 115 static const struct x86_cpu_id ppin_cpuids[] = { 116 X86_MATCH_FEATURE(X86_FEATURE_AMD_PPIN, &ppin_info[X86_VENDOR_AMD]), 117 X86_MATCH_FEATURE(X86_FEATURE_INTEL_PPIN, &ppin_info[X86_VENDOR_INTEL]), 118 119 /* Legacy models without CPUID enumeration */ 120 X86_MATCH_VFM(INTEL_IVYBRIDGE_X, &ppin_info[X86_VENDOR_INTEL]), 121 X86_MATCH_VFM(INTEL_HASWELL_X, &ppin_info[X86_VENDOR_INTEL]), 122 X86_MATCH_VFM(INTEL_BROADWELL_D, &ppin_info[X86_VENDOR_INTEL]), 123 X86_MATCH_VFM(INTEL_BROADWELL_X, &ppin_info[X86_VENDOR_INTEL]), 124 X86_MATCH_VFM(INTEL_SKYLAKE_X, &ppin_info[X86_VENDOR_INTEL]), 125 X86_MATCH_VFM(INTEL_ICELAKE_X, &ppin_info[X86_VENDOR_INTEL]), 126 X86_MATCH_VFM(INTEL_ICELAKE_D, &ppin_info[X86_VENDOR_INTEL]), 127 X86_MATCH_VFM(INTEL_SAPPHIRERAPIDS_X, &ppin_info[X86_VENDOR_INTEL]), 128 X86_MATCH_VFM(INTEL_EMERALDRAPIDS_X, &ppin_info[X86_VENDOR_INTEL]), 129 X86_MATCH_VFM(INTEL_XEON_PHI_KNL, &ppin_info[X86_VENDOR_INTEL]), 130 X86_MATCH_VFM(INTEL_XEON_PHI_KNM, &ppin_info[X86_VENDOR_INTEL]), 131 132 {} 133 }; 134 135 static void ppin_init(struct cpuinfo_x86 *c) 136 { 137 const struct x86_cpu_id *id; 138 unsigned long long val; 139 struct ppin_info *info; 140 141 id = x86_match_cpu(ppin_cpuids); 142 if (!id) 143 return; 144 145 /* 146 * Testing the presence of the MSR is not enough. Need to check 147 * that the PPIN_CTL allows reading of the PPIN. 148 */ 149 info = (struct ppin_info *)id->driver_data; 150 151 if (rdmsrl_safe(info->msr_ppin_ctl, &val)) 152 goto clear_ppin; 153 154 if ((val & 3UL) == 1UL) { 155 /* PPIN locked in disabled mode */ 156 goto clear_ppin; 157 } 158 159 /* If PPIN is disabled, try to enable */ 160 if (!(val & 2UL)) { 161 wrmsrl_safe(info->msr_ppin_ctl, val | 2UL); 162 rdmsrl_safe(info->msr_ppin_ctl, &val); 163 } 164 165 /* Is the enable bit set? */ 166 if (val & 2UL) { 167 c->ppin = __rdmsr(info->msr_ppin); 168 set_cpu_cap(c, info->feature); 169 return; 170 } 171 172 clear_ppin: 173 setup_clear_cpu_cap(info->feature); 174 } 175 176 static void default_init(struct cpuinfo_x86 *c) 177 { 178 #ifdef CONFIG_X86_64 179 cpu_detect_cache_sizes(c); 180 #else 181 /* Not much we can do here... */ 182 /* Check if at least it has cpuid */ 183 if (c->cpuid_level == -1) { 184 /* No cpuid. It must be an ancient CPU */ 185 if (c->x86 == 4) 186 strcpy(c->x86_model_id, "486"); 187 else if (c->x86 == 3) 188 strcpy(c->x86_model_id, "386"); 189 } 190 #endif 191 } 192 193 static const struct cpu_dev default_cpu = { 194 .c_init = default_init, 195 .c_vendor = "Unknown", 196 .c_x86_vendor = X86_VENDOR_UNKNOWN, 197 }; 198 199 static const struct cpu_dev *this_cpu = &default_cpu; 200 201 DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = { 202 #ifdef CONFIG_X86_64 203 /* 204 * We need valid kernel segments for data and code in long mode too 205 * IRET will check the segment types kkeil 2000/10/28 206 * Also sysret mandates a special GDT layout 207 * 208 * TLS descriptors are currently at a different place compared to i386. 209 * Hopefully nobody expects them at a fixed place (Wine?) 210 */ 211 [GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(DESC_CODE32, 0, 0xfffff), 212 [GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(DESC_CODE64, 0, 0xfffff), 213 [GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(DESC_DATA64, 0, 0xfffff), 214 [GDT_ENTRY_DEFAULT_USER32_CS] = GDT_ENTRY_INIT(DESC_CODE32 | DESC_USER, 0, 0xfffff), 215 [GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(DESC_DATA64 | DESC_USER, 0, 0xfffff), 216 [GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(DESC_CODE64 | DESC_USER, 0, 0xfffff), 217 #else 218 [GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(DESC_CODE32, 0, 0xfffff), 219 [GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(DESC_DATA32, 0, 0xfffff), 220 [GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(DESC_CODE32 | DESC_USER, 0, 0xfffff), 221 [GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(DESC_DATA32 | DESC_USER, 0, 0xfffff), 222 /* 223 * Segments used for calling PnP BIOS have byte granularity. 224 * They code segments and data segments have fixed 64k limits, 225 * the transfer segment sizes are set at run time. 226 */ 227 [GDT_ENTRY_PNPBIOS_CS32] = GDT_ENTRY_INIT(DESC_CODE32_BIOS, 0, 0xffff), 228 [GDT_ENTRY_PNPBIOS_CS16] = GDT_ENTRY_INIT(DESC_CODE16, 0, 0xffff), 229 [GDT_ENTRY_PNPBIOS_DS] = GDT_ENTRY_INIT(DESC_DATA16, 0, 0xffff), 230 [GDT_ENTRY_PNPBIOS_TS1] = GDT_ENTRY_INIT(DESC_DATA16, 0, 0), 231 [GDT_ENTRY_PNPBIOS_TS2] = GDT_ENTRY_INIT(DESC_DATA16, 0, 0), 232 /* 233 * The APM segments have byte granularity and their bases 234 * are set at run time. All have 64k limits. 235 */ 236 [GDT_ENTRY_APMBIOS_BASE] = GDT_ENTRY_INIT(DESC_CODE32_BIOS, 0, 0xffff), 237 [GDT_ENTRY_APMBIOS_BASE+1] = GDT_ENTRY_INIT(DESC_CODE16, 0, 0xffff), 238 [GDT_ENTRY_APMBIOS_BASE+2] = GDT_ENTRY_INIT(DESC_DATA32_BIOS, 0, 0xffff), 239 240 [GDT_ENTRY_ESPFIX_SS] = GDT_ENTRY_INIT(DESC_DATA32, 0, 0xfffff), 241 [GDT_ENTRY_PERCPU] = GDT_ENTRY_INIT(DESC_DATA32, 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 /* Standard macro to see if a specific flag is changeable */ 281 static inline bool flag_is_changeable_p(unsigned long flag) 282 { 283 unsigned long f1, f2; 284 285 if (!IS_ENABLED(CONFIG_X86_32)) 286 return true; 287 288 /* 289 * Cyrix and IDT cpus allow disabling of CPUID 290 * so the code below may return different results 291 * when it is executed before and after enabling 292 * the CPUID. Add "volatile" to not allow gcc to 293 * optimize the subsequent calls to this function. 294 */ 295 asm volatile ("pushfl \n\t" 296 "pushfl \n\t" 297 "popl %0 \n\t" 298 "movl %0, %1 \n\t" 299 "xorl %2, %0 \n\t" 300 "pushl %0 \n\t" 301 "popfl \n\t" 302 "pushfl \n\t" 303 "popl %0 \n\t" 304 "popfl \n\t" 305 306 : "=&r" (f1), "=&r" (f2) 307 : "ir" (flag)); 308 309 return (f1 ^ f2) & flag; 310 } 311 312 #ifdef CONFIG_X86_32 313 static int cachesize_override = -1; 314 static int disable_x86_serial_nr = 1; 315 316 static int __init cachesize_setup(char *str) 317 { 318 get_option(&str, &cachesize_override); 319 return 1; 320 } 321 __setup("cachesize=", cachesize_setup); 322 323 /* Probe for the CPUID instruction */ 324 bool have_cpuid_p(void) 325 { 326 return flag_is_changeable_p(X86_EFLAGS_ID); 327 } 328 329 static void squash_the_stupid_serial_number(struct cpuinfo_x86 *c) 330 { 331 unsigned long lo, hi; 332 333 if (!cpu_has(c, X86_FEATURE_PN) || !disable_x86_serial_nr) 334 return; 335 336 /* Disable processor serial number: */ 337 338 rdmsr(MSR_IA32_BBL_CR_CTL, lo, hi); 339 lo |= 0x200000; 340 wrmsr(MSR_IA32_BBL_CR_CTL, lo, hi); 341 342 pr_notice("CPU serial number disabled.\n"); 343 clear_cpu_cap(c, X86_FEATURE_PN); 344 345 /* Disabling the serial number may affect the cpuid level */ 346 c->cpuid_level = cpuid_eax(0); 347 } 348 349 static int __init x86_serial_nr_setup(char *s) 350 { 351 disable_x86_serial_nr = 0; 352 return 1; 353 } 354 __setup("serialnumber", x86_serial_nr_setup); 355 #else 356 static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c) 357 { 358 } 359 #endif 360 361 static __always_inline void setup_smep(struct cpuinfo_x86 *c) 362 { 363 if (cpu_has(c, X86_FEATURE_SMEP)) 364 cr4_set_bits(X86_CR4_SMEP); 365 } 366 367 static __always_inline void setup_smap(struct cpuinfo_x86 *c) 368 { 369 unsigned long eflags = native_save_fl(); 370 371 /* This should have been cleared long ago */ 372 BUG_ON(eflags & X86_EFLAGS_AC); 373 374 if (cpu_has(c, X86_FEATURE_SMAP)) 375 cr4_set_bits(X86_CR4_SMAP); 376 } 377 378 static __always_inline void setup_umip(struct cpuinfo_x86 *c) 379 { 380 /* Check the boot processor, plus build option for UMIP. */ 381 if (!cpu_feature_enabled(X86_FEATURE_UMIP)) 382 goto out; 383 384 /* Check the current processor's cpuid bits. */ 385 if (!cpu_has(c, X86_FEATURE_UMIP)) 386 goto out; 387 388 cr4_set_bits(X86_CR4_UMIP); 389 390 pr_info_once("x86/cpu: User Mode Instruction Prevention (UMIP) activated\n"); 391 392 return; 393 394 out: 395 /* 396 * Make sure UMIP is disabled in case it was enabled in a 397 * previous boot (e.g., via kexec). 398 */ 399 cr4_clear_bits(X86_CR4_UMIP); 400 } 401 402 /* These bits should not change their value after CPU init is finished. */ 403 static const unsigned long cr4_pinned_mask = X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_UMIP | 404 X86_CR4_FSGSBASE | X86_CR4_CET | X86_CR4_FRED; 405 static DEFINE_STATIC_KEY_FALSE_RO(cr_pinning); 406 static unsigned long cr4_pinned_bits __ro_after_init; 407 408 void native_write_cr0(unsigned long val) 409 { 410 unsigned long bits_missing = 0; 411 412 set_register: 413 asm volatile("mov %0,%%cr0": "+r" (val) : : "memory"); 414 415 if (static_branch_likely(&cr_pinning)) { 416 if (unlikely((val & X86_CR0_WP) != X86_CR0_WP)) { 417 bits_missing = X86_CR0_WP; 418 val |= bits_missing; 419 goto set_register; 420 } 421 /* Warn after we've set the missing bits. */ 422 WARN_ONCE(bits_missing, "CR0 WP bit went missing!?\n"); 423 } 424 } 425 EXPORT_SYMBOL(native_write_cr0); 426 427 void __no_profile native_write_cr4(unsigned long val) 428 { 429 unsigned long bits_changed = 0; 430 431 set_register: 432 asm volatile("mov %0,%%cr4": "+r" (val) : : "memory"); 433 434 if (static_branch_likely(&cr_pinning)) { 435 if (unlikely((val & cr4_pinned_mask) != cr4_pinned_bits)) { 436 bits_changed = (val & cr4_pinned_mask) ^ cr4_pinned_bits; 437 val = (val & ~cr4_pinned_mask) | cr4_pinned_bits; 438 goto set_register; 439 } 440 /* Warn after we've corrected the changed bits. */ 441 WARN_ONCE(bits_changed, "pinned CR4 bits changed: 0x%lx!?\n", 442 bits_changed); 443 } 444 } 445 #if IS_MODULE(CONFIG_LKDTM) 446 EXPORT_SYMBOL_GPL(native_write_cr4); 447 #endif 448 449 void cr4_update_irqsoff(unsigned long set, unsigned long clear) 450 { 451 unsigned long newval, cr4 = this_cpu_read(cpu_tlbstate.cr4); 452 453 lockdep_assert_irqs_disabled(); 454 455 newval = (cr4 & ~clear) | set; 456 if (newval != cr4) { 457 this_cpu_write(cpu_tlbstate.cr4, newval); 458 __write_cr4(newval); 459 } 460 } 461 EXPORT_SYMBOL(cr4_update_irqsoff); 462 463 /* Read the CR4 shadow. */ 464 unsigned long cr4_read_shadow(void) 465 { 466 return this_cpu_read(cpu_tlbstate.cr4); 467 } 468 EXPORT_SYMBOL_GPL(cr4_read_shadow); 469 470 void cr4_init(void) 471 { 472 unsigned long cr4 = __read_cr4(); 473 474 if (boot_cpu_has(X86_FEATURE_PCID)) 475 cr4 |= X86_CR4_PCIDE; 476 if (static_branch_likely(&cr_pinning)) 477 cr4 = (cr4 & ~cr4_pinned_mask) | cr4_pinned_bits; 478 479 __write_cr4(cr4); 480 481 /* Initialize cr4 shadow for this CPU. */ 482 this_cpu_write(cpu_tlbstate.cr4, cr4); 483 } 484 485 /* 486 * Once CPU feature detection is finished (and boot params have been 487 * parsed), record any of the sensitive CR bits that are set, and 488 * enable CR pinning. 489 */ 490 static void __init setup_cr_pinning(void) 491 { 492 cr4_pinned_bits = this_cpu_read(cpu_tlbstate.cr4) & cr4_pinned_mask; 493 static_key_enable(&cr_pinning.key); 494 } 495 496 static __init int x86_nofsgsbase_setup(char *arg) 497 { 498 /* Require an exact match without trailing characters. */ 499 if (strlen(arg)) 500 return 0; 501 502 /* Do not emit a message if the feature is not present. */ 503 if (!boot_cpu_has(X86_FEATURE_FSGSBASE)) 504 return 1; 505 506 setup_clear_cpu_cap(X86_FEATURE_FSGSBASE); 507 pr_info("FSGSBASE disabled via kernel command line\n"); 508 return 1; 509 } 510 __setup("nofsgsbase", x86_nofsgsbase_setup); 511 512 /* 513 * Protection Keys are not available in 32-bit mode. 514 */ 515 static bool pku_disabled; 516 517 static __always_inline void setup_pku(struct cpuinfo_x86 *c) 518 { 519 if (c == &boot_cpu_data) { 520 if (pku_disabled || !cpu_feature_enabled(X86_FEATURE_PKU)) 521 return; 522 /* 523 * Setting CR4.PKE will cause the X86_FEATURE_OSPKE cpuid 524 * bit to be set. Enforce it. 525 */ 526 setup_force_cpu_cap(X86_FEATURE_OSPKE); 527 528 } else if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) { 529 return; 530 } 531 532 cr4_set_bits(X86_CR4_PKE); 533 /* Load the default PKRU value */ 534 pkru_write_default(); 535 } 536 537 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 538 static __init int setup_disable_pku(char *arg) 539 { 540 /* 541 * Do not clear the X86_FEATURE_PKU bit. All of the 542 * runtime checks are against OSPKE so clearing the 543 * bit does nothing. 544 * 545 * This way, we will see "pku" in cpuinfo, but not 546 * "ospke", which is exactly what we want. It shows 547 * that the CPU has PKU, but the OS has not enabled it. 548 * This happens to be exactly how a system would look 549 * if we disabled the config option. 550 */ 551 pr_info("x86: 'nopku' specified, disabling Memory Protection Keys\n"); 552 pku_disabled = true; 553 return 1; 554 } 555 __setup("nopku", setup_disable_pku); 556 #endif 557 558 #ifdef CONFIG_X86_KERNEL_IBT 559 560 __noendbr u64 ibt_save(bool disable) 561 { 562 u64 msr = 0; 563 564 if (cpu_feature_enabled(X86_FEATURE_IBT)) { 565 rdmsrl(MSR_IA32_S_CET, msr); 566 if (disable) 567 wrmsrl(MSR_IA32_S_CET, msr & ~CET_ENDBR_EN); 568 } 569 570 return msr; 571 } 572 573 __noendbr void ibt_restore(u64 save) 574 { 575 u64 msr; 576 577 if (cpu_feature_enabled(X86_FEATURE_IBT)) { 578 rdmsrl(MSR_IA32_S_CET, msr); 579 msr &= ~CET_ENDBR_EN; 580 msr |= (save & CET_ENDBR_EN); 581 wrmsrl(MSR_IA32_S_CET, msr); 582 } 583 } 584 585 #endif 586 587 static __always_inline void setup_cet(struct cpuinfo_x86 *c) 588 { 589 bool user_shstk, kernel_ibt; 590 591 if (!IS_ENABLED(CONFIG_X86_CET)) 592 return; 593 594 kernel_ibt = HAS_KERNEL_IBT && cpu_feature_enabled(X86_FEATURE_IBT); 595 user_shstk = cpu_feature_enabled(X86_FEATURE_SHSTK) && 596 IS_ENABLED(CONFIG_X86_USER_SHADOW_STACK); 597 598 if (!kernel_ibt && !user_shstk) 599 return; 600 601 if (user_shstk) 602 set_cpu_cap(c, X86_FEATURE_USER_SHSTK); 603 604 if (kernel_ibt) 605 wrmsrl(MSR_IA32_S_CET, CET_ENDBR_EN); 606 else 607 wrmsrl(MSR_IA32_S_CET, 0); 608 609 cr4_set_bits(X86_CR4_CET); 610 611 if (kernel_ibt && ibt_selftest()) { 612 pr_err("IBT selftest: Failed!\n"); 613 wrmsrl(MSR_IA32_S_CET, 0); 614 setup_clear_cpu_cap(X86_FEATURE_IBT); 615 } 616 } 617 618 __noendbr void cet_disable(void) 619 { 620 if (!(cpu_feature_enabled(X86_FEATURE_IBT) || 621 cpu_feature_enabled(X86_FEATURE_SHSTK))) 622 return; 623 624 wrmsrl(MSR_IA32_S_CET, 0); 625 wrmsrl(MSR_IA32_U_CET, 0); 626 } 627 628 /* 629 * Some CPU features depend on higher CPUID levels, which may not always 630 * be available due to CPUID level capping or broken virtualization 631 * software. Add those features to this table to auto-disable them. 632 */ 633 struct cpuid_dependent_feature { 634 u32 feature; 635 u32 level; 636 }; 637 638 static const struct cpuid_dependent_feature 639 cpuid_dependent_features[] = { 640 { X86_FEATURE_MWAIT, CPUID_LEAF_MWAIT }, 641 { X86_FEATURE_DCA, CPUID_LEAF_DCA }, 642 { X86_FEATURE_XSAVE, CPUID_LEAF_XSTATE }, 643 { 0, 0 } 644 }; 645 646 static void filter_cpuid_features(struct cpuinfo_x86 *c, bool warn) 647 { 648 const struct cpuid_dependent_feature *df; 649 650 for (df = cpuid_dependent_features; df->feature; df++) { 651 652 if (!cpu_has(c, df->feature)) 653 continue; 654 /* 655 * Note: cpuid_level is set to -1 if unavailable, but 656 * extended_extended_level is set to 0 if unavailable 657 * and the legitimate extended levels are all negative 658 * when signed; hence the weird messing around with 659 * signs here... 660 */ 661 if (!((s32)df->level < 0 ? 662 (u32)df->level > (u32)c->extended_cpuid_level : 663 (s32)df->level > (s32)c->cpuid_level)) 664 continue; 665 666 clear_cpu_cap(c, df->feature); 667 if (!warn) 668 continue; 669 670 pr_warn("CPU: CPU feature %s disabled, no CPUID level 0x%x\n", 671 x86_cap_flags[df->feature], df->level); 672 } 673 } 674 675 /* 676 * Naming convention should be: <Name> [(<Codename>)] 677 * This table only is used unless init_<vendor>() below doesn't set it; 678 * in particular, if CPUID levels 0x80000002..4 are supported, this 679 * isn't used 680 */ 681 682 /* Look up CPU names by table lookup. */ 683 static const char *table_lookup_model(struct cpuinfo_x86 *c) 684 { 685 #ifdef CONFIG_X86_32 686 const struct legacy_cpu_model_info *info; 687 688 if (c->x86_model >= 16) 689 return NULL; /* Range check */ 690 691 if (!this_cpu) 692 return NULL; 693 694 info = this_cpu->legacy_models; 695 696 while (info->family) { 697 if (info->family == c->x86) 698 return info->model_names[c->x86_model]; 699 info++; 700 } 701 #endif 702 return NULL; /* Not found */ 703 } 704 705 /* Aligned to unsigned long to avoid split lock in atomic bitmap ops */ 706 __u32 cpu_caps_cleared[NCAPINTS + NBUGINTS] __aligned(sizeof(unsigned long)); 707 __u32 cpu_caps_set[NCAPINTS + NBUGINTS] __aligned(sizeof(unsigned long)); 708 709 #ifdef CONFIG_X86_32 710 /* The 32-bit entry code needs to find cpu_entry_area. */ 711 DEFINE_PER_CPU(struct cpu_entry_area *, cpu_entry_area); 712 #endif 713 714 /* Load the original GDT from the per-cpu structure */ 715 void load_direct_gdt(int cpu) 716 { 717 struct desc_ptr gdt_descr; 718 719 gdt_descr.address = (long)get_cpu_gdt_rw(cpu); 720 gdt_descr.size = GDT_SIZE - 1; 721 load_gdt(&gdt_descr); 722 } 723 EXPORT_SYMBOL_GPL(load_direct_gdt); 724 725 /* Load a fixmap remapping of the per-cpu GDT */ 726 void load_fixmap_gdt(int cpu) 727 { 728 struct desc_ptr gdt_descr; 729 730 gdt_descr.address = (long)get_cpu_gdt_ro(cpu); 731 gdt_descr.size = GDT_SIZE - 1; 732 load_gdt(&gdt_descr); 733 } 734 EXPORT_SYMBOL_GPL(load_fixmap_gdt); 735 736 /** 737 * switch_gdt_and_percpu_base - Switch to direct GDT and runtime per CPU base 738 * @cpu: The CPU number for which this is invoked 739 * 740 * Invoked during early boot to switch from early GDT and early per CPU to 741 * the direct GDT and the runtime per CPU area. On 32-bit the percpu base 742 * switch is implicit by loading the direct GDT. On 64bit this requires 743 * to update GSBASE. 744 */ 745 void __init switch_gdt_and_percpu_base(int cpu) 746 { 747 load_direct_gdt(cpu); 748 749 #ifdef CONFIG_X86_64 750 /* 751 * No need to load %gs. It is already correct. 752 * 753 * Writing %gs on 64bit would zero GSBASE which would make any per 754 * CPU operation up to the point of the wrmsrl() fault. 755 * 756 * Set GSBASE to the new offset. Until the wrmsrl() happens the 757 * early mapping is still valid. That means the GSBASE update will 758 * lose any prior per CPU data which was not copied over in 759 * setup_per_cpu_areas(). 760 * 761 * This works even with stackprotector enabled because the 762 * per CPU stack canary is 0 in both per CPU areas. 763 */ 764 wrmsrl(MSR_GS_BASE, cpu_kernelmode_gs_base(cpu)); 765 #else 766 /* 767 * %fs is already set to __KERNEL_PERCPU, but after switching GDT 768 * it is required to load FS again so that the 'hidden' part is 769 * updated from the new GDT. Up to this point the early per CPU 770 * translation is active. Any content of the early per CPU data 771 * which was not copied over in setup_per_cpu_areas() is lost. 772 */ 773 loadsegment(fs, __KERNEL_PERCPU); 774 #endif 775 } 776 777 static const struct cpu_dev *cpu_devs[X86_VENDOR_NUM] = {}; 778 779 static void get_model_name(struct cpuinfo_x86 *c) 780 { 781 unsigned int *v; 782 char *p, *q, *s; 783 784 if (c->extended_cpuid_level < 0x80000004) 785 return; 786 787 v = (unsigned int *)c->x86_model_id; 788 cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]); 789 cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]); 790 cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]); 791 c->x86_model_id[48] = 0; 792 793 /* Trim whitespace */ 794 p = q = s = &c->x86_model_id[0]; 795 796 while (*p == ' ') 797 p++; 798 799 while (*p) { 800 /* Note the last non-whitespace index */ 801 if (!isspace(*p)) 802 s = q; 803 804 *q++ = *p++; 805 } 806 807 *(s + 1) = '\0'; 808 } 809 810 void cpu_detect_cache_sizes(struct cpuinfo_x86 *c) 811 { 812 unsigned int n, dummy, ebx, ecx, edx, l2size; 813 814 n = c->extended_cpuid_level; 815 816 if (n >= 0x80000005) { 817 cpuid(0x80000005, &dummy, &ebx, &ecx, &edx); 818 c->x86_cache_size = (ecx>>24) + (edx>>24); 819 #ifdef CONFIG_X86_64 820 /* On K8 L1 TLB is inclusive, so don't count it */ 821 c->x86_tlbsize = 0; 822 #endif 823 } 824 825 if (n < 0x80000006) /* Some chips just has a large L1. */ 826 return; 827 828 cpuid(0x80000006, &dummy, &ebx, &ecx, &edx); 829 l2size = ecx >> 16; 830 831 #ifdef CONFIG_X86_64 832 c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff); 833 #else 834 /* do processor-specific cache resizing */ 835 if (this_cpu->legacy_cache_size) 836 l2size = this_cpu->legacy_cache_size(c, l2size); 837 838 /* Allow user to override all this if necessary. */ 839 if (cachesize_override != -1) 840 l2size = cachesize_override; 841 842 if (l2size == 0) 843 return; /* Again, no L2 cache is possible */ 844 #endif 845 846 c->x86_cache_size = l2size; 847 } 848 849 u16 __read_mostly tlb_lli_4k; 850 u16 __read_mostly tlb_lli_2m; 851 u16 __read_mostly tlb_lli_4m; 852 u16 __read_mostly tlb_lld_4k; 853 u16 __read_mostly tlb_lld_2m; 854 u16 __read_mostly tlb_lld_4m; 855 u16 __read_mostly tlb_lld_1g; 856 857 static void cpu_detect_tlb(struct cpuinfo_x86 *c) 858 { 859 if (this_cpu->c_detect_tlb) 860 this_cpu->c_detect_tlb(c); 861 862 pr_info("Last level iTLB entries: 4KB %d, 2MB %d, 4MB %d\n", 863 tlb_lli_4k, tlb_lli_2m, tlb_lli_4m); 864 865 pr_info("Last level dTLB entries: 4KB %d, 2MB %d, 4MB %d, 1GB %d\n", 866 tlb_lld_4k, tlb_lld_2m, tlb_lld_4m, tlb_lld_1g); 867 } 868 869 void get_cpu_vendor(struct cpuinfo_x86 *c) 870 { 871 char *v = c->x86_vendor_id; 872 int i; 873 874 for (i = 0; i < X86_VENDOR_NUM; i++) { 875 if (!cpu_devs[i]) 876 break; 877 878 if (!strcmp(v, cpu_devs[i]->c_ident[0]) || 879 (cpu_devs[i]->c_ident[1] && 880 !strcmp(v, cpu_devs[i]->c_ident[1]))) { 881 882 this_cpu = cpu_devs[i]; 883 c->x86_vendor = this_cpu->c_x86_vendor; 884 return; 885 } 886 } 887 888 pr_err_once("CPU: vendor_id '%s' unknown, using generic init.\n" \ 889 "CPU: Your system may be unstable.\n", v); 890 891 c->x86_vendor = X86_VENDOR_UNKNOWN; 892 this_cpu = &default_cpu; 893 } 894 895 void cpu_detect(struct cpuinfo_x86 *c) 896 { 897 /* Get vendor name */ 898 cpuid(0x00000000, (unsigned int *)&c->cpuid_level, 899 (unsigned int *)&c->x86_vendor_id[0], 900 (unsigned int *)&c->x86_vendor_id[8], 901 (unsigned int *)&c->x86_vendor_id[4]); 902 903 c->x86 = 4; 904 /* Intel-defined flags: level 0x00000001 */ 905 if (c->cpuid_level >= 0x00000001) { 906 u32 junk, tfms, cap0, misc; 907 908 cpuid(0x00000001, &tfms, &misc, &junk, &cap0); 909 c->x86 = x86_family(tfms); 910 c->x86_model = x86_model(tfms); 911 c->x86_stepping = x86_stepping(tfms); 912 913 if (cap0 & (1<<19)) { 914 c->x86_clflush_size = ((misc >> 8) & 0xff) * 8; 915 c->x86_cache_alignment = c->x86_clflush_size; 916 } 917 } 918 } 919 920 static void apply_forced_caps(struct cpuinfo_x86 *c) 921 { 922 int i; 923 924 for (i = 0; i < NCAPINTS + NBUGINTS; i++) { 925 c->x86_capability[i] &= ~cpu_caps_cleared[i]; 926 c->x86_capability[i] |= cpu_caps_set[i]; 927 } 928 } 929 930 static void init_speculation_control(struct cpuinfo_x86 *c) 931 { 932 /* 933 * The Intel SPEC_CTRL CPUID bit implies IBRS and IBPB support, 934 * and they also have a different bit for STIBP support. Also, 935 * a hypervisor might have set the individual AMD bits even on 936 * Intel CPUs, for finer-grained selection of what's available. 937 */ 938 if (cpu_has(c, X86_FEATURE_SPEC_CTRL)) { 939 set_cpu_cap(c, X86_FEATURE_IBRS); 940 set_cpu_cap(c, X86_FEATURE_IBPB); 941 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 942 } 943 944 if (cpu_has(c, X86_FEATURE_INTEL_STIBP)) 945 set_cpu_cap(c, X86_FEATURE_STIBP); 946 947 if (cpu_has(c, X86_FEATURE_SPEC_CTRL_SSBD) || 948 cpu_has(c, X86_FEATURE_VIRT_SSBD)) 949 set_cpu_cap(c, X86_FEATURE_SSBD); 950 951 if (cpu_has(c, X86_FEATURE_AMD_IBRS)) { 952 set_cpu_cap(c, X86_FEATURE_IBRS); 953 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 954 } 955 956 if (cpu_has(c, X86_FEATURE_AMD_IBPB)) 957 set_cpu_cap(c, X86_FEATURE_IBPB); 958 959 if (cpu_has(c, X86_FEATURE_AMD_STIBP)) { 960 set_cpu_cap(c, X86_FEATURE_STIBP); 961 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 962 } 963 964 if (cpu_has(c, X86_FEATURE_AMD_SSBD)) { 965 set_cpu_cap(c, X86_FEATURE_SSBD); 966 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 967 clear_cpu_cap(c, X86_FEATURE_VIRT_SSBD); 968 } 969 } 970 971 void get_cpu_cap(struct cpuinfo_x86 *c) 972 { 973 u32 eax, ebx, ecx, edx; 974 975 /* Intel-defined flags: level 0x00000001 */ 976 if (c->cpuid_level >= 0x00000001) { 977 cpuid(0x00000001, &eax, &ebx, &ecx, &edx); 978 979 c->x86_capability[CPUID_1_ECX] = ecx; 980 c->x86_capability[CPUID_1_EDX] = edx; 981 } 982 983 /* Thermal and Power Management Leaf: level 0x00000006 (eax) */ 984 if (c->cpuid_level >= 0x00000006) 985 c->x86_capability[CPUID_6_EAX] = cpuid_eax(0x00000006); 986 987 /* Additional Intel-defined flags: level 0x00000007 */ 988 if (c->cpuid_level >= 0x00000007) { 989 cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx); 990 c->x86_capability[CPUID_7_0_EBX] = ebx; 991 c->x86_capability[CPUID_7_ECX] = ecx; 992 c->x86_capability[CPUID_7_EDX] = edx; 993 994 /* Check valid sub-leaf index before accessing it */ 995 if (eax >= 1) { 996 cpuid_count(0x00000007, 1, &eax, &ebx, &ecx, &edx); 997 c->x86_capability[CPUID_7_1_EAX] = eax; 998 } 999 } 1000 1001 /* Extended state features: level 0x0000000d */ 1002 if (c->cpuid_level >= 0x0000000d) { 1003 cpuid_count(0x0000000d, 1, &eax, &ebx, &ecx, &edx); 1004 1005 c->x86_capability[CPUID_D_1_EAX] = eax; 1006 } 1007 1008 /* AMD-defined flags: level 0x80000001 */ 1009 eax = cpuid_eax(0x80000000); 1010 c->extended_cpuid_level = eax; 1011 1012 if ((eax & 0xffff0000) == 0x80000000) { 1013 if (eax >= 0x80000001) { 1014 cpuid(0x80000001, &eax, &ebx, &ecx, &edx); 1015 1016 c->x86_capability[CPUID_8000_0001_ECX] = ecx; 1017 c->x86_capability[CPUID_8000_0001_EDX] = edx; 1018 } 1019 } 1020 1021 if (c->extended_cpuid_level >= 0x80000007) { 1022 cpuid(0x80000007, &eax, &ebx, &ecx, &edx); 1023 1024 c->x86_capability[CPUID_8000_0007_EBX] = ebx; 1025 c->x86_power = edx; 1026 } 1027 1028 if (c->extended_cpuid_level >= 0x80000008) { 1029 cpuid(0x80000008, &eax, &ebx, &ecx, &edx); 1030 c->x86_capability[CPUID_8000_0008_EBX] = ebx; 1031 } 1032 1033 if (c->extended_cpuid_level >= 0x8000000a) 1034 c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a); 1035 1036 if (c->extended_cpuid_level >= 0x8000001f) 1037 c->x86_capability[CPUID_8000_001F_EAX] = cpuid_eax(0x8000001f); 1038 1039 if (c->extended_cpuid_level >= 0x80000021) 1040 c->x86_capability[CPUID_8000_0021_EAX] = cpuid_eax(0x80000021); 1041 1042 init_scattered_cpuid_features(c); 1043 init_speculation_control(c); 1044 1045 /* 1046 * Clear/Set all flags overridden by options, after probe. 1047 * This needs to happen each time we re-probe, which may happen 1048 * several times during CPU initialization. 1049 */ 1050 apply_forced_caps(c); 1051 } 1052 1053 void get_cpu_address_sizes(struct cpuinfo_x86 *c) 1054 { 1055 u32 eax, ebx, ecx, edx; 1056 1057 if (!cpu_has(c, X86_FEATURE_CPUID) || 1058 (c->extended_cpuid_level < 0x80000008)) { 1059 if (IS_ENABLED(CONFIG_X86_64)) { 1060 c->x86_clflush_size = 64; 1061 c->x86_phys_bits = 36; 1062 c->x86_virt_bits = 48; 1063 } else { 1064 c->x86_clflush_size = 32; 1065 c->x86_virt_bits = 32; 1066 c->x86_phys_bits = 32; 1067 1068 if (cpu_has(c, X86_FEATURE_PAE) || 1069 cpu_has(c, X86_FEATURE_PSE36)) 1070 c->x86_phys_bits = 36; 1071 } 1072 } else { 1073 cpuid(0x80000008, &eax, &ebx, &ecx, &edx); 1074 1075 c->x86_virt_bits = (eax >> 8) & 0xff; 1076 c->x86_phys_bits = eax & 0xff; 1077 1078 /* Provide a sane default if not enumerated: */ 1079 if (!c->x86_clflush_size) 1080 c->x86_clflush_size = 32; 1081 } 1082 1083 c->x86_cache_bits = c->x86_phys_bits; 1084 c->x86_cache_alignment = c->x86_clflush_size; 1085 } 1086 1087 static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c) 1088 { 1089 int i; 1090 1091 /* 1092 * First of all, decide if this is a 486 or higher 1093 * It's a 486 if we can modify the AC flag 1094 */ 1095 if (flag_is_changeable_p(X86_EFLAGS_AC)) 1096 c->x86 = 4; 1097 else 1098 c->x86 = 3; 1099 1100 for (i = 0; i < X86_VENDOR_NUM; i++) 1101 if (cpu_devs[i] && cpu_devs[i]->c_identify) { 1102 c->x86_vendor_id[0] = 0; 1103 cpu_devs[i]->c_identify(c); 1104 if (c->x86_vendor_id[0]) { 1105 get_cpu_vendor(c); 1106 break; 1107 } 1108 } 1109 } 1110 1111 #define NO_SPECULATION BIT(0) 1112 #define NO_MELTDOWN BIT(1) 1113 #define NO_SSB BIT(2) 1114 #define NO_L1TF BIT(3) 1115 #define NO_MDS BIT(4) 1116 #define MSBDS_ONLY BIT(5) 1117 #define NO_SWAPGS BIT(6) 1118 #define NO_ITLB_MULTIHIT BIT(7) 1119 #define NO_SPECTRE_V2 BIT(8) 1120 #define NO_MMIO BIT(9) 1121 #define NO_EIBRS_PBRSB BIT(10) 1122 #define NO_BHI BIT(11) 1123 1124 #define VULNWL(vendor, family, model, whitelist) \ 1125 X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, whitelist) 1126 1127 #define VULNWL_INTEL(vfm, whitelist) \ 1128 X86_MATCH_VFM(vfm, whitelist) 1129 1130 #define VULNWL_AMD(family, whitelist) \ 1131 VULNWL(AMD, family, X86_MODEL_ANY, whitelist) 1132 1133 #define VULNWL_HYGON(family, whitelist) \ 1134 VULNWL(HYGON, family, X86_MODEL_ANY, whitelist) 1135 1136 static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = { 1137 VULNWL(ANY, 4, X86_MODEL_ANY, NO_SPECULATION), 1138 VULNWL(CENTAUR, 5, X86_MODEL_ANY, NO_SPECULATION), 1139 VULNWL(INTEL, 5, X86_MODEL_ANY, NO_SPECULATION), 1140 VULNWL(NSC, 5, X86_MODEL_ANY, NO_SPECULATION), 1141 VULNWL(VORTEX, 5, X86_MODEL_ANY, NO_SPECULATION), 1142 VULNWL(VORTEX, 6, X86_MODEL_ANY, NO_SPECULATION), 1143 1144 /* Intel Family 6 */ 1145 VULNWL_INTEL(INTEL_TIGERLAKE, NO_MMIO), 1146 VULNWL_INTEL(INTEL_TIGERLAKE_L, NO_MMIO), 1147 VULNWL_INTEL(INTEL_ALDERLAKE, NO_MMIO), 1148 VULNWL_INTEL(INTEL_ALDERLAKE_L, NO_MMIO), 1149 1150 VULNWL_INTEL(INTEL_ATOM_SALTWELL, NO_SPECULATION | NO_ITLB_MULTIHIT), 1151 VULNWL_INTEL(INTEL_ATOM_SALTWELL_TABLET, NO_SPECULATION | NO_ITLB_MULTIHIT), 1152 VULNWL_INTEL(INTEL_ATOM_SALTWELL_MID, NO_SPECULATION | NO_ITLB_MULTIHIT), 1153 VULNWL_INTEL(INTEL_ATOM_BONNELL, NO_SPECULATION | NO_ITLB_MULTIHIT), 1154 VULNWL_INTEL(INTEL_ATOM_BONNELL_MID, NO_SPECULATION | NO_ITLB_MULTIHIT), 1155 1156 VULNWL_INTEL(INTEL_ATOM_SILVERMONT, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1157 VULNWL_INTEL(INTEL_ATOM_SILVERMONT_D, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1158 VULNWL_INTEL(INTEL_ATOM_SILVERMONT_MID, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1159 VULNWL_INTEL(INTEL_ATOM_AIRMONT, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1160 VULNWL_INTEL(INTEL_XEON_PHI_KNL, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1161 VULNWL_INTEL(INTEL_XEON_PHI_KNM, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT), 1162 1163 VULNWL_INTEL(INTEL_CORE_YONAH, NO_SSB), 1164 1165 VULNWL_INTEL(INTEL_ATOM_SILVERMONT_MID2,NO_SSB | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | MSBDS_ONLY), 1166 VULNWL_INTEL(INTEL_ATOM_AIRMONT_NP, NO_SSB | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT), 1167 1168 VULNWL_INTEL(INTEL_ATOM_GOLDMONT, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1169 VULNWL_INTEL(INTEL_ATOM_GOLDMONT_D, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO), 1170 VULNWL_INTEL(INTEL_ATOM_GOLDMONT_PLUS, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_EIBRS_PBRSB), 1171 1172 /* 1173 * Technically, swapgs isn't serializing on AMD (despite it previously 1174 * being documented as such in the APM). But according to AMD, %gs is 1175 * updated non-speculatively, and the issuing of %gs-relative memory 1176 * operands will be blocked until the %gs update completes, which is 1177 * good enough for our purposes. 1178 */ 1179 1180 VULNWL_INTEL(INTEL_ATOM_TREMONT, NO_EIBRS_PBRSB), 1181 VULNWL_INTEL(INTEL_ATOM_TREMONT_L, NO_EIBRS_PBRSB), 1182 VULNWL_INTEL(INTEL_ATOM_TREMONT_D, NO_ITLB_MULTIHIT | NO_EIBRS_PBRSB), 1183 1184 /* AMD Family 0xf - 0x12 */ 1185 VULNWL_AMD(0x0f, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_BHI), 1186 VULNWL_AMD(0x10, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_BHI), 1187 VULNWL_AMD(0x11, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_BHI), 1188 VULNWL_AMD(0x12, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_BHI), 1189 1190 /* FAMILY_ANY must be last, otherwise 0x0f - 0x12 matches won't work */ 1191 VULNWL_AMD(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_EIBRS_PBRSB | NO_BHI), 1192 VULNWL_HYGON(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_EIBRS_PBRSB | NO_BHI), 1193 1194 /* Zhaoxin Family 7 */ 1195 VULNWL(CENTAUR, 7, X86_MODEL_ANY, NO_SPECTRE_V2 | NO_SWAPGS | NO_MMIO | NO_BHI), 1196 VULNWL(ZHAOXIN, 7, X86_MODEL_ANY, NO_SPECTRE_V2 | NO_SWAPGS | NO_MMIO | NO_BHI), 1197 {} 1198 }; 1199 1200 #define VULNBL(vendor, family, model, blacklist) \ 1201 X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, blacklist) 1202 1203 #define VULNBL_INTEL_STEPS(vfm, max_stepping, issues) \ 1204 X86_MATCH_VFM_STEPS(vfm, X86_STEP_MIN, max_stepping, issues) 1205 1206 #define VULNBL_INTEL_TYPE(vfm, cpu_type, issues) \ 1207 X86_MATCH_VFM_CPU_TYPE(vfm, INTEL_CPU_TYPE_##cpu_type, issues) 1208 1209 #define VULNBL_AMD(family, blacklist) \ 1210 VULNBL(AMD, family, X86_MODEL_ANY, blacklist) 1211 1212 #define VULNBL_HYGON(family, blacklist) \ 1213 VULNBL(HYGON, family, X86_MODEL_ANY, blacklist) 1214 1215 #define SRBDS BIT(0) 1216 /* CPU is affected by X86_BUG_MMIO_STALE_DATA */ 1217 #define MMIO BIT(1) 1218 /* CPU is affected by Shared Buffers Data Sampling (SBDS), a variant of X86_BUG_MMIO_STALE_DATA */ 1219 #define MMIO_SBDS BIT(2) 1220 /* CPU is affected by RETbleed, speculating where you would not expect it */ 1221 #define RETBLEED BIT(3) 1222 /* CPU is affected by SMT (cross-thread) return predictions */ 1223 #define SMT_RSB BIT(4) 1224 /* CPU is affected by SRSO */ 1225 #define SRSO BIT(5) 1226 /* CPU is affected by GDS */ 1227 #define GDS BIT(6) 1228 /* CPU is affected by Register File Data Sampling */ 1229 #define RFDS BIT(7) 1230 1231 static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = { 1232 VULNBL_INTEL_STEPS(INTEL_IVYBRIDGE, X86_STEP_MAX, SRBDS), 1233 VULNBL_INTEL_STEPS(INTEL_HASWELL, X86_STEP_MAX, SRBDS), 1234 VULNBL_INTEL_STEPS(INTEL_HASWELL_L, X86_STEP_MAX, SRBDS), 1235 VULNBL_INTEL_STEPS(INTEL_HASWELL_G, X86_STEP_MAX, SRBDS), 1236 VULNBL_INTEL_STEPS(INTEL_HASWELL_X, X86_STEP_MAX, MMIO), 1237 VULNBL_INTEL_STEPS(INTEL_BROADWELL_D, X86_STEP_MAX, MMIO), 1238 VULNBL_INTEL_STEPS(INTEL_BROADWELL_G, X86_STEP_MAX, SRBDS), 1239 VULNBL_INTEL_STEPS(INTEL_BROADWELL_X, X86_STEP_MAX, MMIO), 1240 VULNBL_INTEL_STEPS(INTEL_BROADWELL, X86_STEP_MAX, SRBDS), 1241 VULNBL_INTEL_STEPS(INTEL_SKYLAKE_X, X86_STEP_MAX, MMIO | RETBLEED | GDS), 1242 VULNBL_INTEL_STEPS(INTEL_SKYLAKE_L, X86_STEP_MAX, MMIO | RETBLEED | GDS | SRBDS), 1243 VULNBL_INTEL_STEPS(INTEL_SKYLAKE, X86_STEP_MAX, MMIO | RETBLEED | GDS | SRBDS), 1244 VULNBL_INTEL_STEPS(INTEL_KABYLAKE_L, X86_STEP_MAX, MMIO | RETBLEED | GDS | SRBDS), 1245 VULNBL_INTEL_STEPS(INTEL_KABYLAKE, X86_STEP_MAX, MMIO | RETBLEED | GDS | SRBDS), 1246 VULNBL_INTEL_STEPS(INTEL_CANNONLAKE_L, X86_STEP_MAX, RETBLEED), 1247 VULNBL_INTEL_STEPS(INTEL_ICELAKE_L, X86_STEP_MAX, MMIO | MMIO_SBDS | RETBLEED | GDS), 1248 VULNBL_INTEL_STEPS(INTEL_ICELAKE_D, X86_STEP_MAX, MMIO | GDS), 1249 VULNBL_INTEL_STEPS(INTEL_ICELAKE_X, X86_STEP_MAX, MMIO | GDS), 1250 VULNBL_INTEL_STEPS(INTEL_COMETLAKE, X86_STEP_MAX, MMIO | MMIO_SBDS | RETBLEED | GDS), 1251 VULNBL_INTEL_STEPS(INTEL_COMETLAKE_L, 0x0, MMIO | RETBLEED), 1252 VULNBL_INTEL_STEPS(INTEL_COMETLAKE_L, X86_STEP_MAX, MMIO | MMIO_SBDS | RETBLEED | GDS), 1253 VULNBL_INTEL_STEPS(INTEL_TIGERLAKE_L, X86_STEP_MAX, GDS), 1254 VULNBL_INTEL_STEPS(INTEL_TIGERLAKE, X86_STEP_MAX, GDS), 1255 VULNBL_INTEL_STEPS(INTEL_LAKEFIELD, X86_STEP_MAX, MMIO | MMIO_SBDS | RETBLEED), 1256 VULNBL_INTEL_STEPS(INTEL_ROCKETLAKE, X86_STEP_MAX, MMIO | RETBLEED | GDS), 1257 VULNBL_INTEL_TYPE(INTEL_ALDERLAKE, ATOM, RFDS), 1258 VULNBL_INTEL_STEPS(INTEL_ALDERLAKE_L, X86_STEP_MAX, RFDS), 1259 VULNBL_INTEL_TYPE(INTEL_RAPTORLAKE, ATOM, RFDS), 1260 VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE_P, X86_STEP_MAX, RFDS), 1261 VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE_S, X86_STEP_MAX, RFDS), 1262 VULNBL_INTEL_STEPS(INTEL_ATOM_GRACEMONT, X86_STEP_MAX, RFDS), 1263 VULNBL_INTEL_STEPS(INTEL_ATOM_TREMONT, X86_STEP_MAX, MMIO | MMIO_SBDS | RFDS), 1264 VULNBL_INTEL_STEPS(INTEL_ATOM_TREMONT_D, X86_STEP_MAX, MMIO | RFDS), 1265 VULNBL_INTEL_STEPS(INTEL_ATOM_TREMONT_L, X86_STEP_MAX, MMIO | MMIO_SBDS | RFDS), 1266 VULNBL_INTEL_STEPS(INTEL_ATOM_GOLDMONT, X86_STEP_MAX, RFDS), 1267 VULNBL_INTEL_STEPS(INTEL_ATOM_GOLDMONT_D, X86_STEP_MAX, RFDS), 1268 VULNBL_INTEL_STEPS(INTEL_ATOM_GOLDMONT_PLUS, X86_STEP_MAX, RFDS), 1269 1270 VULNBL_AMD(0x15, RETBLEED), 1271 VULNBL_AMD(0x16, RETBLEED), 1272 VULNBL_AMD(0x17, RETBLEED | SMT_RSB | SRSO), 1273 VULNBL_HYGON(0x18, RETBLEED | SMT_RSB | SRSO), 1274 VULNBL_AMD(0x19, SRSO), 1275 VULNBL_AMD(0x1a, SRSO), 1276 {} 1277 }; 1278 1279 static bool __init cpu_matches(const struct x86_cpu_id *table, unsigned long which) 1280 { 1281 const struct x86_cpu_id *m = x86_match_cpu(table); 1282 1283 return m && !!(m->driver_data & which); 1284 } 1285 1286 u64 x86_read_arch_cap_msr(void) 1287 { 1288 u64 x86_arch_cap_msr = 0; 1289 1290 if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES)) 1291 rdmsrl(MSR_IA32_ARCH_CAPABILITIES, x86_arch_cap_msr); 1292 1293 return x86_arch_cap_msr; 1294 } 1295 1296 static bool arch_cap_mmio_immune(u64 x86_arch_cap_msr) 1297 { 1298 return (x86_arch_cap_msr & ARCH_CAP_FBSDP_NO && 1299 x86_arch_cap_msr & ARCH_CAP_PSDP_NO && 1300 x86_arch_cap_msr & ARCH_CAP_SBDR_SSDP_NO); 1301 } 1302 1303 static bool __init vulnerable_to_rfds(u64 x86_arch_cap_msr) 1304 { 1305 /* The "immunity" bit trumps everything else: */ 1306 if (x86_arch_cap_msr & ARCH_CAP_RFDS_NO) 1307 return false; 1308 1309 /* 1310 * VMMs set ARCH_CAP_RFDS_CLEAR for processors not in the blacklist to 1311 * indicate that mitigation is needed because guest is running on a 1312 * vulnerable hardware or may migrate to such hardware: 1313 */ 1314 if (x86_arch_cap_msr & ARCH_CAP_RFDS_CLEAR) 1315 return true; 1316 1317 /* Only consult the blacklist when there is no enumeration: */ 1318 return cpu_matches(cpu_vuln_blacklist, RFDS); 1319 } 1320 1321 static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) 1322 { 1323 u64 x86_arch_cap_msr = x86_read_arch_cap_msr(); 1324 1325 /* Set ITLB_MULTIHIT bug if cpu is not in the whitelist and not mitigated */ 1326 if (!cpu_matches(cpu_vuln_whitelist, NO_ITLB_MULTIHIT) && 1327 !(x86_arch_cap_msr & ARCH_CAP_PSCHANGE_MC_NO)) 1328 setup_force_cpu_bug(X86_BUG_ITLB_MULTIHIT); 1329 1330 if (cpu_matches(cpu_vuln_whitelist, NO_SPECULATION)) 1331 return; 1332 1333 setup_force_cpu_bug(X86_BUG_SPECTRE_V1); 1334 1335 if (!cpu_matches(cpu_vuln_whitelist, NO_SPECTRE_V2)) { 1336 setup_force_cpu_bug(X86_BUG_SPECTRE_V2); 1337 setup_force_cpu_bug(X86_BUG_SPECTRE_V2_USER); 1338 } 1339 1340 if (!cpu_matches(cpu_vuln_whitelist, NO_SSB) && 1341 !(x86_arch_cap_msr & ARCH_CAP_SSB_NO) && 1342 !cpu_has(c, X86_FEATURE_AMD_SSB_NO)) 1343 setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS); 1344 1345 /* 1346 * AMD's AutoIBRS is equivalent to Intel's eIBRS - use the Intel feature 1347 * flag and protect from vendor-specific bugs via the whitelist. 1348 * 1349 * Don't use AutoIBRS when SNP is enabled because it degrades host 1350 * userspace indirect branch performance. 1351 */ 1352 if ((x86_arch_cap_msr & ARCH_CAP_IBRS_ALL) || 1353 (cpu_has(c, X86_FEATURE_AUTOIBRS) && 1354 !cpu_feature_enabled(X86_FEATURE_SEV_SNP))) { 1355 setup_force_cpu_cap(X86_FEATURE_IBRS_ENHANCED); 1356 if (!cpu_matches(cpu_vuln_whitelist, NO_EIBRS_PBRSB) && 1357 !(x86_arch_cap_msr & ARCH_CAP_PBRSB_NO)) 1358 setup_force_cpu_bug(X86_BUG_EIBRS_PBRSB); 1359 } 1360 1361 if (!cpu_matches(cpu_vuln_whitelist, NO_MDS) && 1362 !(x86_arch_cap_msr & ARCH_CAP_MDS_NO)) { 1363 setup_force_cpu_bug(X86_BUG_MDS); 1364 if (cpu_matches(cpu_vuln_whitelist, MSBDS_ONLY)) 1365 setup_force_cpu_bug(X86_BUG_MSBDS_ONLY); 1366 } 1367 1368 if (!cpu_matches(cpu_vuln_whitelist, NO_SWAPGS)) 1369 setup_force_cpu_bug(X86_BUG_SWAPGS); 1370 1371 /* 1372 * When the CPU is not mitigated for TAA (TAA_NO=0) set TAA bug when: 1373 * - TSX is supported or 1374 * - TSX_CTRL is present 1375 * 1376 * TSX_CTRL check is needed for cases when TSX could be disabled before 1377 * the kernel boot e.g. kexec. 1378 * TSX_CTRL check alone is not sufficient for cases when the microcode 1379 * update is not present or running as guest that don't get TSX_CTRL. 1380 */ 1381 if (!(x86_arch_cap_msr & ARCH_CAP_TAA_NO) && 1382 (cpu_has(c, X86_FEATURE_RTM) || 1383 (x86_arch_cap_msr & ARCH_CAP_TSX_CTRL_MSR))) 1384 setup_force_cpu_bug(X86_BUG_TAA); 1385 1386 /* 1387 * SRBDS affects CPUs which support RDRAND or RDSEED and are listed 1388 * in the vulnerability blacklist. 1389 * 1390 * Some of the implications and mitigation of Shared Buffers Data 1391 * Sampling (SBDS) are similar to SRBDS. Give SBDS same treatment as 1392 * SRBDS. 1393 */ 1394 if ((cpu_has(c, X86_FEATURE_RDRAND) || 1395 cpu_has(c, X86_FEATURE_RDSEED)) && 1396 cpu_matches(cpu_vuln_blacklist, SRBDS | MMIO_SBDS)) 1397 setup_force_cpu_bug(X86_BUG_SRBDS); 1398 1399 /* 1400 * Processor MMIO Stale Data bug enumeration 1401 * 1402 * Affected CPU list is generally enough to enumerate the vulnerability, 1403 * but for virtualization case check for ARCH_CAP MSR bits also, VMM may 1404 * not want the guest to enumerate the bug. 1405 * 1406 * Set X86_BUG_MMIO_UNKNOWN for CPUs that are neither in the blacklist, 1407 * nor in the whitelist and also don't enumerate MSR ARCH_CAP MMIO bits. 1408 */ 1409 if (!arch_cap_mmio_immune(x86_arch_cap_msr)) { 1410 if (cpu_matches(cpu_vuln_blacklist, MMIO)) 1411 setup_force_cpu_bug(X86_BUG_MMIO_STALE_DATA); 1412 else if (!cpu_matches(cpu_vuln_whitelist, NO_MMIO)) 1413 setup_force_cpu_bug(X86_BUG_MMIO_UNKNOWN); 1414 } 1415 1416 if (!cpu_has(c, X86_FEATURE_BTC_NO)) { 1417 if (cpu_matches(cpu_vuln_blacklist, RETBLEED) || (x86_arch_cap_msr & ARCH_CAP_RSBA)) 1418 setup_force_cpu_bug(X86_BUG_RETBLEED); 1419 } 1420 1421 if (cpu_matches(cpu_vuln_blacklist, SMT_RSB)) 1422 setup_force_cpu_bug(X86_BUG_SMT_RSB); 1423 1424 if (!cpu_has(c, X86_FEATURE_SRSO_NO)) { 1425 if (cpu_matches(cpu_vuln_blacklist, SRSO)) 1426 setup_force_cpu_bug(X86_BUG_SRSO); 1427 } 1428 1429 /* 1430 * Check if CPU is vulnerable to GDS. If running in a virtual machine on 1431 * an affected processor, the VMM may have disabled the use of GATHER by 1432 * disabling AVX2. The only way to do this in HW is to clear XCR0[2], 1433 * which means that AVX will be disabled. 1434 */ 1435 if (cpu_matches(cpu_vuln_blacklist, GDS) && !(x86_arch_cap_msr & ARCH_CAP_GDS_NO) && 1436 boot_cpu_has(X86_FEATURE_AVX)) 1437 setup_force_cpu_bug(X86_BUG_GDS); 1438 1439 if (vulnerable_to_rfds(x86_arch_cap_msr)) 1440 setup_force_cpu_bug(X86_BUG_RFDS); 1441 1442 /* When virtualized, eIBRS could be hidden, assume vulnerable */ 1443 if (!(x86_arch_cap_msr & ARCH_CAP_BHI_NO) && 1444 !cpu_matches(cpu_vuln_whitelist, NO_BHI) && 1445 (boot_cpu_has(X86_FEATURE_IBRS_ENHANCED) || 1446 boot_cpu_has(X86_FEATURE_HYPERVISOR))) 1447 setup_force_cpu_bug(X86_BUG_BHI); 1448 1449 if (cpu_has(c, X86_FEATURE_AMD_IBPB) && !cpu_has(c, X86_FEATURE_AMD_IBPB_RET)) 1450 setup_force_cpu_bug(X86_BUG_IBPB_NO_RET); 1451 1452 if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN)) 1453 return; 1454 1455 /* Rogue Data Cache Load? No! */ 1456 if (x86_arch_cap_msr & ARCH_CAP_RDCL_NO) 1457 return; 1458 1459 setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN); 1460 1461 if (cpu_matches(cpu_vuln_whitelist, NO_L1TF)) 1462 return; 1463 1464 setup_force_cpu_bug(X86_BUG_L1TF); 1465 } 1466 1467 /* 1468 * The NOPL instruction is supposed to exist on all CPUs of family >= 6; 1469 * unfortunately, that's not true in practice because of early VIA 1470 * chips and (more importantly) broken virtualizers that are not easy 1471 * to detect. In the latter case it doesn't even *fail* reliably, so 1472 * probing for it doesn't even work. Disable it completely on 32-bit 1473 * unless we can find a reliable way to detect all the broken cases. 1474 * Enable it explicitly on 64-bit for non-constant inputs of cpu_has(). 1475 */ 1476 static void detect_nopl(void) 1477 { 1478 #ifdef CONFIG_X86_32 1479 setup_clear_cpu_cap(X86_FEATURE_NOPL); 1480 #else 1481 setup_force_cpu_cap(X86_FEATURE_NOPL); 1482 #endif 1483 } 1484 1485 static inline bool parse_set_clear_cpuid(char *arg, bool set) 1486 { 1487 char *opt; 1488 int taint = 0; 1489 1490 while (arg) { 1491 bool found __maybe_unused = false; 1492 unsigned int bit; 1493 1494 opt = strsep(&arg, ","); 1495 1496 /* 1497 * Handle naked numbers first for feature flags which don't 1498 * have names. It doesn't make sense for a bug not to have a 1499 * name so don't handle bug flags here. 1500 */ 1501 if (!kstrtouint(opt, 10, &bit)) { 1502 if (bit < NCAPINTS * 32) { 1503 1504 if (set) { 1505 pr_warn("setcpuid: force-enabling CPU feature flag:"); 1506 setup_force_cpu_cap(bit); 1507 } else { 1508 pr_warn("clearcpuid: force-disabling CPU feature flag:"); 1509 setup_clear_cpu_cap(bit); 1510 } 1511 /* empty-string, i.e., ""-defined feature flags */ 1512 if (!x86_cap_flags[bit]) 1513 pr_cont(" %d:%d\n", bit >> 5, bit & 31); 1514 else 1515 pr_cont(" %s\n", x86_cap_flags[bit]); 1516 1517 taint++; 1518 } 1519 /* 1520 * The assumption is that there are no feature names with only 1521 * numbers in the name thus go to the next argument. 1522 */ 1523 continue; 1524 } 1525 1526 for (bit = 0; bit < 32 * (NCAPINTS + NBUGINTS); bit++) { 1527 const char *flag; 1528 const char *kind; 1529 1530 if (bit < 32 * NCAPINTS) { 1531 flag = x86_cap_flags[bit]; 1532 kind = "feature"; 1533 } else { 1534 kind = "bug"; 1535 flag = x86_bug_flags[bit - (32 * NCAPINTS)]; 1536 } 1537 1538 if (!flag) 1539 continue; 1540 1541 if (strcmp(flag, opt)) 1542 continue; 1543 1544 if (set) { 1545 pr_warn("setcpuid: force-enabling CPU %s flag: %s\n", 1546 kind, flag); 1547 setup_force_cpu_cap(bit); 1548 } else { 1549 pr_warn("clearcpuid: force-disabling CPU %s flag: %s\n", 1550 kind, flag); 1551 setup_clear_cpu_cap(bit); 1552 } 1553 taint++; 1554 found = true; 1555 break; 1556 } 1557 1558 if (!found) 1559 pr_warn("%s: unknown CPU flag: %s", set ? "setcpuid" : "clearcpuid", opt); 1560 } 1561 1562 return taint; 1563 } 1564 1565 1566 /* 1567 * We parse cpu parameters early because fpu__init_system() is executed 1568 * before parse_early_param(). 1569 */ 1570 static void __init cpu_parse_early_param(void) 1571 { 1572 bool cpuid_taint = false; 1573 char arg[128]; 1574 int arglen; 1575 1576 #ifdef CONFIG_X86_32 1577 if (cmdline_find_option_bool(boot_command_line, "no387")) 1578 #ifdef CONFIG_MATH_EMULATION 1579 setup_clear_cpu_cap(X86_FEATURE_FPU); 1580 #else 1581 pr_err("Option 'no387' required CONFIG_MATH_EMULATION enabled.\n"); 1582 #endif 1583 1584 if (cmdline_find_option_bool(boot_command_line, "nofxsr")) 1585 setup_clear_cpu_cap(X86_FEATURE_FXSR); 1586 #endif 1587 1588 if (cmdline_find_option_bool(boot_command_line, "noxsave")) 1589 setup_clear_cpu_cap(X86_FEATURE_XSAVE); 1590 1591 if (cmdline_find_option_bool(boot_command_line, "noxsaveopt")) 1592 setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT); 1593 1594 if (cmdline_find_option_bool(boot_command_line, "noxsaves")) 1595 setup_clear_cpu_cap(X86_FEATURE_XSAVES); 1596 1597 if (cmdline_find_option_bool(boot_command_line, "nousershstk")) 1598 setup_clear_cpu_cap(X86_FEATURE_USER_SHSTK); 1599 1600 /* Minimize the gap between FRED is available and available but disabled. */ 1601 arglen = cmdline_find_option(boot_command_line, "fred", arg, sizeof(arg)); 1602 if (arglen != 2 || strncmp(arg, "on", 2)) 1603 setup_clear_cpu_cap(X86_FEATURE_FRED); 1604 1605 arglen = cmdline_find_option(boot_command_line, "clearcpuid", arg, sizeof(arg)); 1606 if (arglen > 0) 1607 cpuid_taint |= parse_set_clear_cpuid(arg, false); 1608 1609 arglen = cmdline_find_option(boot_command_line, "setcpuid", arg, sizeof(arg)); 1610 if (arglen > 0) 1611 cpuid_taint |= parse_set_clear_cpuid(arg, true); 1612 1613 if (cpuid_taint) { 1614 pr_warn("!!! setcpuid=/clearcpuid= in use, this is for TESTING ONLY, may break things horribly. Tainting kernel.\n"); 1615 add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); 1616 } 1617 } 1618 1619 /* 1620 * Do minimum CPU detection early. 1621 * Fields really needed: vendor, cpuid_level, family, model, mask, 1622 * cache alignment. 1623 * The others are not touched to avoid unwanted side effects. 1624 * 1625 * WARNING: this function is only called on the boot CPU. Don't add code 1626 * here that is supposed to run on all CPUs. 1627 */ 1628 static void __init early_identify_cpu(struct cpuinfo_x86 *c) 1629 { 1630 memset(&c->x86_capability, 0, sizeof(c->x86_capability)); 1631 c->extended_cpuid_level = 0; 1632 1633 if (!have_cpuid_p()) 1634 identify_cpu_without_cpuid(c); 1635 1636 /* cyrix could have cpuid enabled via c_identify()*/ 1637 if (have_cpuid_p()) { 1638 cpu_detect(c); 1639 get_cpu_vendor(c); 1640 intel_unlock_cpuid_leafs(c); 1641 get_cpu_cap(c); 1642 setup_force_cpu_cap(X86_FEATURE_CPUID); 1643 get_cpu_address_sizes(c); 1644 cpu_parse_early_param(); 1645 1646 cpu_init_topology(c); 1647 1648 if (this_cpu->c_early_init) 1649 this_cpu->c_early_init(c); 1650 1651 c->cpu_index = 0; 1652 filter_cpuid_features(c, false); 1653 check_cpufeature_deps(c); 1654 1655 if (this_cpu->c_bsp_init) 1656 this_cpu->c_bsp_init(c); 1657 } else { 1658 setup_clear_cpu_cap(X86_FEATURE_CPUID); 1659 get_cpu_address_sizes(c); 1660 cpu_init_topology(c); 1661 } 1662 1663 setup_force_cpu_cap(X86_FEATURE_ALWAYS); 1664 1665 cpu_set_bug_bits(c); 1666 1667 sld_setup(c); 1668 1669 #ifdef CONFIG_X86_32 1670 /* 1671 * Regardless of whether PCID is enumerated, the SDM says 1672 * that it can't be enabled in 32-bit mode. 1673 */ 1674 setup_clear_cpu_cap(X86_FEATURE_PCID); 1675 #endif 1676 1677 /* 1678 * Later in the boot process pgtable_l5_enabled() relies on 1679 * cpu_feature_enabled(X86_FEATURE_LA57). If 5-level paging is not 1680 * enabled by this point we need to clear the feature bit to avoid 1681 * false-positives at the later stage. 1682 * 1683 * pgtable_l5_enabled() can be false here for several reasons: 1684 * - 5-level paging is disabled compile-time; 1685 * - it's 32-bit kernel; 1686 * - machine doesn't support 5-level paging; 1687 * - user specified 'no5lvl' in kernel command line. 1688 */ 1689 if (!pgtable_l5_enabled()) 1690 setup_clear_cpu_cap(X86_FEATURE_LA57); 1691 1692 detect_nopl(); 1693 } 1694 1695 void __init init_cpu_devs(void) 1696 { 1697 const struct cpu_dev *const *cdev; 1698 int count = 0; 1699 1700 for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) { 1701 const struct cpu_dev *cpudev = *cdev; 1702 1703 if (count >= X86_VENDOR_NUM) 1704 break; 1705 cpu_devs[count] = cpudev; 1706 count++; 1707 } 1708 } 1709 1710 void __init early_cpu_init(void) 1711 { 1712 #ifdef CONFIG_PROCESSOR_SELECT 1713 unsigned int i, j; 1714 1715 pr_info("KERNEL supported cpus:\n"); 1716 #endif 1717 1718 init_cpu_devs(); 1719 1720 #ifdef CONFIG_PROCESSOR_SELECT 1721 for (i = 0; i < X86_VENDOR_NUM && cpu_devs[i]; i++) { 1722 for (j = 0; j < 2; j++) { 1723 if (!cpu_devs[i]->c_ident[j]) 1724 continue; 1725 pr_info(" %s %s\n", cpu_devs[i]->c_vendor, 1726 cpu_devs[i]->c_ident[j]); 1727 } 1728 } 1729 #endif 1730 1731 early_identify_cpu(&boot_cpu_data); 1732 } 1733 1734 static bool detect_null_seg_behavior(void) 1735 { 1736 /* 1737 * Empirically, writing zero to a segment selector on AMD does 1738 * not clear the base, whereas writing zero to a segment 1739 * selector on Intel does clear the base. Intel's behavior 1740 * allows slightly faster context switches in the common case 1741 * where GS is unused by the prev and next threads. 1742 * 1743 * Since neither vendor documents this anywhere that I can see, 1744 * detect it directly instead of hard-coding the choice by 1745 * vendor. 1746 * 1747 * I've designated AMD's behavior as the "bug" because it's 1748 * counterintuitive and less friendly. 1749 */ 1750 1751 unsigned long old_base, tmp; 1752 rdmsrl(MSR_FS_BASE, old_base); 1753 wrmsrl(MSR_FS_BASE, 1); 1754 loadsegment(fs, 0); 1755 rdmsrl(MSR_FS_BASE, tmp); 1756 wrmsrl(MSR_FS_BASE, old_base); 1757 return tmp == 0; 1758 } 1759 1760 void check_null_seg_clears_base(struct cpuinfo_x86 *c) 1761 { 1762 /* BUG_NULL_SEG is only relevant with 64bit userspace */ 1763 if (!IS_ENABLED(CONFIG_X86_64)) 1764 return; 1765 1766 if (cpu_has(c, X86_FEATURE_NULL_SEL_CLR_BASE)) 1767 return; 1768 1769 /* 1770 * CPUID bit above wasn't set. If this kernel is still running 1771 * as a HV guest, then the HV has decided not to advertize 1772 * that CPUID bit for whatever reason. For example, one 1773 * member of the migration pool might be vulnerable. Which 1774 * means, the bug is present: set the BUG flag and return. 1775 */ 1776 if (cpu_has(c, X86_FEATURE_HYPERVISOR)) { 1777 set_cpu_bug(c, X86_BUG_NULL_SEG); 1778 return; 1779 } 1780 1781 /* 1782 * Zen2 CPUs also have this behaviour, but no CPUID bit. 1783 * 0x18 is the respective family for Hygon. 1784 */ 1785 if ((c->x86 == 0x17 || c->x86 == 0x18) && 1786 detect_null_seg_behavior()) 1787 return; 1788 1789 /* All the remaining ones are affected */ 1790 set_cpu_bug(c, X86_BUG_NULL_SEG); 1791 } 1792 1793 static void generic_identify(struct cpuinfo_x86 *c) 1794 { 1795 c->extended_cpuid_level = 0; 1796 1797 if (!have_cpuid_p()) 1798 identify_cpu_without_cpuid(c); 1799 1800 /* cyrix could have cpuid enabled via c_identify()*/ 1801 if (!have_cpuid_p()) 1802 return; 1803 1804 cpu_detect(c); 1805 1806 get_cpu_vendor(c); 1807 intel_unlock_cpuid_leafs(c); 1808 get_cpu_cap(c); 1809 1810 get_cpu_address_sizes(c); 1811 1812 get_model_name(c); /* Default name */ 1813 1814 /* 1815 * ESPFIX is a strange bug. All real CPUs have it. Paravirt 1816 * systems that run Linux at CPL > 0 may or may not have the 1817 * issue, but, even if they have the issue, there's absolutely 1818 * nothing we can do about it because we can't use the real IRET 1819 * instruction. 1820 * 1821 * NB: For the time being, only 32-bit kernels support 1822 * X86_BUG_ESPFIX as such. 64-bit kernels directly choose 1823 * whether to apply espfix using paravirt hooks. If any 1824 * non-paravirt system ever shows up that does *not* have the 1825 * ESPFIX issue, we can change this. 1826 */ 1827 #ifdef CONFIG_X86_32 1828 set_cpu_bug(c, X86_BUG_ESPFIX); 1829 #endif 1830 } 1831 1832 /* 1833 * This does the hard work of actually picking apart the CPU stuff... 1834 */ 1835 static void identify_cpu(struct cpuinfo_x86 *c) 1836 { 1837 int i; 1838 1839 c->loops_per_jiffy = loops_per_jiffy; 1840 c->x86_cache_size = 0; 1841 c->x86_vendor = X86_VENDOR_UNKNOWN; 1842 c->x86_model = c->x86_stepping = 0; /* So far unknown... */ 1843 c->x86_vendor_id[0] = '\0'; /* Unset */ 1844 c->x86_model_id[0] = '\0'; /* Unset */ 1845 #ifdef CONFIG_X86_64 1846 c->x86_clflush_size = 64; 1847 c->x86_phys_bits = 36; 1848 c->x86_virt_bits = 48; 1849 #else 1850 c->cpuid_level = -1; /* CPUID not detected */ 1851 c->x86_clflush_size = 32; 1852 c->x86_phys_bits = 32; 1853 c->x86_virt_bits = 32; 1854 #endif 1855 c->x86_cache_alignment = c->x86_clflush_size; 1856 memset(&c->x86_capability, 0, sizeof(c->x86_capability)); 1857 #ifdef CONFIG_X86_VMX_FEATURE_NAMES 1858 memset(&c->vmx_capability, 0, sizeof(c->vmx_capability)); 1859 #endif 1860 1861 generic_identify(c); 1862 1863 cpu_parse_topology(c); 1864 1865 if (this_cpu->c_identify) 1866 this_cpu->c_identify(c); 1867 1868 /* Clear/Set all flags overridden by options, after probe */ 1869 apply_forced_caps(c); 1870 1871 /* 1872 * Set default APIC and TSC_DEADLINE MSR fencing flag. AMD and 1873 * Hygon will clear it in ->c_init() below. 1874 */ 1875 set_cpu_cap(c, X86_FEATURE_APIC_MSRS_FENCE); 1876 1877 /* 1878 * Vendor-specific initialization. In this section we 1879 * canonicalize the feature flags, meaning if there are 1880 * features a certain CPU supports which CPUID doesn't 1881 * tell us, CPUID claiming incorrect flags, or other bugs, 1882 * we handle them here. 1883 * 1884 * At the end of this section, c->x86_capability better 1885 * indicate the features this CPU genuinely supports! 1886 */ 1887 if (this_cpu->c_init) 1888 this_cpu->c_init(c); 1889 1890 bus_lock_init(); 1891 1892 /* Disable the PN if appropriate */ 1893 squash_the_stupid_serial_number(c); 1894 1895 /* Set up SMEP/SMAP/UMIP */ 1896 setup_smep(c); 1897 setup_smap(c); 1898 setup_umip(c); 1899 1900 /* Enable FSGSBASE instructions if available. */ 1901 if (cpu_has(c, X86_FEATURE_FSGSBASE)) { 1902 cr4_set_bits(X86_CR4_FSGSBASE); 1903 elf_hwcap2 |= HWCAP2_FSGSBASE; 1904 } 1905 1906 /* 1907 * The vendor-specific functions might have changed features. 1908 * Now we do "generic changes." 1909 */ 1910 1911 /* Filter out anything that depends on CPUID levels we don't have */ 1912 filter_cpuid_features(c, true); 1913 1914 /* Check for unmet dependencies based on the CPUID dependency table */ 1915 check_cpufeature_deps(c); 1916 1917 /* If the model name is still unset, do table lookup. */ 1918 if (!c->x86_model_id[0]) { 1919 const char *p; 1920 p = table_lookup_model(c); 1921 if (p) 1922 strcpy(c->x86_model_id, p); 1923 else 1924 /* Last resort... */ 1925 sprintf(c->x86_model_id, "%02x/%02x", 1926 c->x86, c->x86_model); 1927 } 1928 1929 x86_init_rdrand(c); 1930 setup_pku(c); 1931 setup_cet(c); 1932 1933 /* 1934 * Clear/Set all flags overridden by options, need do it 1935 * before following smp all cpus cap AND. 1936 */ 1937 apply_forced_caps(c); 1938 1939 /* 1940 * On SMP, boot_cpu_data holds the common feature set between 1941 * all CPUs; so make sure that we indicate which features are 1942 * common between the CPUs. The first time this routine gets 1943 * executed, c == &boot_cpu_data. 1944 */ 1945 if (c != &boot_cpu_data) { 1946 /* AND the already accumulated flags with these */ 1947 for (i = 0; i < NCAPINTS; i++) 1948 boot_cpu_data.x86_capability[i] &= c->x86_capability[i]; 1949 1950 /* OR, i.e. replicate the bug flags */ 1951 for (i = NCAPINTS; i < NCAPINTS + NBUGINTS; i++) 1952 c->x86_capability[i] |= boot_cpu_data.x86_capability[i]; 1953 } 1954 1955 ppin_init(c); 1956 1957 /* Init Machine Check Exception if available. */ 1958 mcheck_cpu_init(c); 1959 1960 numa_add_cpu(smp_processor_id()); 1961 } 1962 1963 /* 1964 * Set up the CPU state needed to execute SYSENTER/SYSEXIT instructions 1965 * on 32-bit kernels: 1966 */ 1967 #ifdef CONFIG_X86_32 1968 void enable_sep_cpu(void) 1969 { 1970 struct tss_struct *tss; 1971 int cpu; 1972 1973 if (!boot_cpu_has(X86_FEATURE_SEP)) 1974 return; 1975 1976 cpu = get_cpu(); 1977 tss = &per_cpu(cpu_tss_rw, cpu); 1978 1979 /* 1980 * We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field -- 1981 * see the big comment in struct x86_hw_tss's definition. 1982 */ 1983 1984 tss->x86_tss.ss1 = __KERNEL_CS; 1985 wrmsr(MSR_IA32_SYSENTER_CS, tss->x86_tss.ss1, 0); 1986 wrmsr(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_entry_stack(cpu) + 1), 0); 1987 wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0); 1988 1989 put_cpu(); 1990 } 1991 #endif 1992 1993 static __init void identify_boot_cpu(void) 1994 { 1995 identify_cpu(&boot_cpu_data); 1996 if (HAS_KERNEL_IBT && cpu_feature_enabled(X86_FEATURE_IBT)) 1997 pr_info("CET detected: Indirect Branch Tracking enabled\n"); 1998 #ifdef CONFIG_X86_32 1999 enable_sep_cpu(); 2000 #endif 2001 cpu_detect_tlb(&boot_cpu_data); 2002 setup_cr_pinning(); 2003 2004 tsx_init(); 2005 tdx_init(); 2006 lkgs_init(); 2007 } 2008 2009 void identify_secondary_cpu(unsigned int cpu) 2010 { 2011 struct cpuinfo_x86 *c = &cpu_data(cpu); 2012 2013 /* Copy boot_cpu_data only on the first bringup */ 2014 if (!c->initialized) 2015 *c = boot_cpu_data; 2016 c->cpu_index = cpu; 2017 2018 identify_cpu(c); 2019 #ifdef CONFIG_X86_32 2020 enable_sep_cpu(); 2021 #endif 2022 x86_spec_ctrl_setup_ap(); 2023 update_srbds_msr(); 2024 if (boot_cpu_has_bug(X86_BUG_GDS)) 2025 update_gds_msr(); 2026 2027 tsx_ap_init(); 2028 c->initialized = true; 2029 } 2030 2031 void print_cpu_info(struct cpuinfo_x86 *c) 2032 { 2033 const char *vendor = NULL; 2034 2035 if (c->x86_vendor < X86_VENDOR_NUM) { 2036 vendor = this_cpu->c_vendor; 2037 } else { 2038 if (c->cpuid_level >= 0) 2039 vendor = c->x86_vendor_id; 2040 } 2041 2042 if (vendor && !strstr(c->x86_model_id, vendor)) 2043 pr_cont("%s ", vendor); 2044 2045 if (c->x86_model_id[0]) 2046 pr_cont("%s", c->x86_model_id); 2047 else 2048 pr_cont("%d86", c->x86); 2049 2050 pr_cont(" (family: 0x%x, model: 0x%x", c->x86, c->x86_model); 2051 2052 if (c->x86_stepping || c->cpuid_level >= 0) 2053 pr_cont(", stepping: 0x%x)\n", c->x86_stepping); 2054 else 2055 pr_cont(")\n"); 2056 } 2057 2058 /* 2059 * clearcpuid= and setcpuid= were already parsed in cpu_parse_early_param(). 2060 * These dummy functions prevent them from becoming an environment variable for 2061 * init. 2062 */ 2063 2064 static __init int setup_clearcpuid(char *arg) 2065 { 2066 return 1; 2067 } 2068 __setup("clearcpuid=", setup_clearcpuid); 2069 2070 static __init int setup_setcpuid(char *arg) 2071 { 2072 return 1; 2073 } 2074 __setup("setcpuid=", setup_setcpuid); 2075 2076 DEFINE_PER_CPU_CACHE_HOT(struct task_struct *, current_task) = &init_task; 2077 EXPORT_PER_CPU_SYMBOL(current_task); 2078 EXPORT_PER_CPU_SYMBOL(const_current_task); 2079 2080 DEFINE_PER_CPU_CACHE_HOT(int, __preempt_count) = INIT_PREEMPT_COUNT; 2081 EXPORT_PER_CPU_SYMBOL(__preempt_count); 2082 2083 DEFINE_PER_CPU_CACHE_HOT(unsigned long, cpu_current_top_of_stack) = TOP_OF_INIT_STACK; 2084 2085 #ifdef CONFIG_X86_64 2086 /* 2087 * Note: Do not make this dependant on CONFIG_MITIGATION_CALL_DEPTH_TRACKING 2088 * so that this space is reserved in the hot cache section even when the 2089 * mitigation is disabled. 2090 */ 2091 DEFINE_PER_CPU_CACHE_HOT(u64, __x86_call_depth); 2092 EXPORT_PER_CPU_SYMBOL(__x86_call_depth); 2093 2094 static void wrmsrl_cstar(unsigned long val) 2095 { 2096 /* 2097 * Intel CPUs do not support 32-bit SYSCALL. Writing to MSR_CSTAR 2098 * is so far ignored by the CPU, but raises a #VE trap in a TDX 2099 * guest. Avoid the pointless write on all Intel CPUs. 2100 */ 2101 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) 2102 wrmsrl(MSR_CSTAR, val); 2103 } 2104 2105 static inline void idt_syscall_init(void) 2106 { 2107 wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64); 2108 2109 if (ia32_enabled()) { 2110 wrmsrl_cstar((unsigned long)entry_SYSCALL_compat); 2111 /* 2112 * This only works on Intel CPUs. 2113 * On AMD CPUs these MSRs are 32-bit, CPU truncates MSR_IA32_SYSENTER_EIP. 2114 * This does not cause SYSENTER to jump to the wrong location, because 2115 * AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit). 2116 */ 2117 wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS); 2118 wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 2119 (unsigned long)(cpu_entry_stack(smp_processor_id()) + 1)); 2120 wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat); 2121 } else { 2122 wrmsrl_cstar((unsigned long)entry_SYSCALL32_ignore); 2123 wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG); 2124 wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL); 2125 wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL); 2126 } 2127 2128 /* 2129 * Flags to clear on syscall; clear as much as possible 2130 * to minimize user space-kernel interference. 2131 */ 2132 wrmsrl(MSR_SYSCALL_MASK, 2133 X86_EFLAGS_CF|X86_EFLAGS_PF|X86_EFLAGS_AF| 2134 X86_EFLAGS_ZF|X86_EFLAGS_SF|X86_EFLAGS_TF| 2135 X86_EFLAGS_IF|X86_EFLAGS_DF|X86_EFLAGS_OF| 2136 X86_EFLAGS_IOPL|X86_EFLAGS_NT|X86_EFLAGS_RF| 2137 X86_EFLAGS_AC|X86_EFLAGS_ID); 2138 } 2139 2140 /* May not be marked __init: used by software suspend */ 2141 void syscall_init(void) 2142 { 2143 /* The default user and kernel segments */ 2144 wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS); 2145 2146 /* 2147 * Except the IA32_STAR MSR, there is NO need to setup SYSCALL and 2148 * SYSENTER MSRs for FRED, because FRED uses the ring 3 FRED 2149 * entrypoint for SYSCALL and SYSENTER, and ERETU is the only legit 2150 * instruction to return to ring 3 (both sysexit and sysret cause 2151 * #UD when FRED is enabled). 2152 */ 2153 if (!cpu_feature_enabled(X86_FEATURE_FRED)) 2154 idt_syscall_init(); 2155 } 2156 #endif /* CONFIG_X86_64 */ 2157 2158 #ifdef CONFIG_STACKPROTECTOR 2159 DEFINE_PER_CPU_CACHE_HOT(unsigned long, __stack_chk_guard); 2160 #ifndef CONFIG_SMP 2161 EXPORT_PER_CPU_SYMBOL(__stack_chk_guard); 2162 #endif 2163 #endif 2164 2165 /* 2166 * Clear all 6 debug registers: 2167 */ 2168 static void clear_all_debug_regs(void) 2169 { 2170 int i; 2171 2172 for (i = 0; i < 8; i++) { 2173 /* Ignore db4, db5 */ 2174 if ((i == 4) || (i == 5)) 2175 continue; 2176 2177 set_debugreg(0, i); 2178 } 2179 } 2180 2181 #ifdef CONFIG_KGDB 2182 /* 2183 * Restore debug regs if using kgdbwait and you have a kernel debugger 2184 * connection established. 2185 */ 2186 static void dbg_restore_debug_regs(void) 2187 { 2188 if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break)) 2189 arch_kgdb_ops.correct_hw_break(); 2190 } 2191 #else /* ! CONFIG_KGDB */ 2192 #define dbg_restore_debug_regs() 2193 #endif /* ! CONFIG_KGDB */ 2194 2195 static inline void setup_getcpu(int cpu) 2196 { 2197 unsigned long cpudata = vdso_encode_cpunode(cpu, early_cpu_to_node(cpu)); 2198 struct desc_struct d = { }; 2199 2200 if (boot_cpu_has(X86_FEATURE_RDTSCP) || boot_cpu_has(X86_FEATURE_RDPID)) 2201 wrmsr(MSR_TSC_AUX, cpudata, 0); 2202 2203 /* Store CPU and node number in limit. */ 2204 d.limit0 = cpudata; 2205 d.limit1 = cpudata >> 16; 2206 2207 d.type = 5; /* RO data, expand down, accessed */ 2208 d.dpl = 3; /* Visible to user code */ 2209 d.s = 1; /* Not a system segment */ 2210 d.p = 1; /* Present */ 2211 d.d = 1; /* 32-bit */ 2212 2213 write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_CPUNODE, &d, DESCTYPE_S); 2214 } 2215 2216 #ifdef CONFIG_X86_64 2217 static inline void tss_setup_ist(struct tss_struct *tss) 2218 { 2219 /* Set up the per-CPU TSS IST stacks */ 2220 tss->x86_tss.ist[IST_INDEX_DF] = __this_cpu_ist_top_va(DF); 2221 tss->x86_tss.ist[IST_INDEX_NMI] = __this_cpu_ist_top_va(NMI); 2222 tss->x86_tss.ist[IST_INDEX_DB] = __this_cpu_ist_top_va(DB); 2223 tss->x86_tss.ist[IST_INDEX_MCE] = __this_cpu_ist_top_va(MCE); 2224 /* Only mapped when SEV-ES is active */ 2225 tss->x86_tss.ist[IST_INDEX_VC] = __this_cpu_ist_top_va(VC); 2226 } 2227 #else /* CONFIG_X86_64 */ 2228 static inline void tss_setup_ist(struct tss_struct *tss) { } 2229 #endif /* !CONFIG_X86_64 */ 2230 2231 static inline void tss_setup_io_bitmap(struct tss_struct *tss) 2232 { 2233 tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID; 2234 2235 #ifdef CONFIG_X86_IOPL_IOPERM 2236 tss->io_bitmap.prev_max = 0; 2237 tss->io_bitmap.prev_sequence = 0; 2238 memset(tss->io_bitmap.bitmap, 0xff, sizeof(tss->io_bitmap.bitmap)); 2239 /* 2240 * Invalidate the extra array entry past the end of the all 2241 * permission bitmap as required by the hardware. 2242 */ 2243 tss->io_bitmap.mapall[IO_BITMAP_LONGS] = ~0UL; 2244 #endif 2245 } 2246 2247 /* 2248 * Setup everything needed to handle exceptions from the IDT, including the IST 2249 * exceptions which use paranoid_entry(). 2250 */ 2251 void cpu_init_exception_handling(bool boot_cpu) 2252 { 2253 struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw); 2254 int cpu = raw_smp_processor_id(); 2255 2256 /* paranoid_entry() gets the CPU number from the GDT */ 2257 setup_getcpu(cpu); 2258 2259 /* For IDT mode, IST vectors need to be set in TSS. */ 2260 if (!cpu_feature_enabled(X86_FEATURE_FRED)) 2261 tss_setup_ist(tss); 2262 tss_setup_io_bitmap(tss); 2263 set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); 2264 2265 load_TR_desc(); 2266 2267 /* GHCB needs to be setup to handle #VC. */ 2268 setup_ghcb(); 2269 2270 if (cpu_feature_enabled(X86_FEATURE_FRED)) { 2271 /* The boot CPU has enabled FRED during early boot */ 2272 if (!boot_cpu) 2273 cpu_init_fred_exceptions(); 2274 2275 cpu_init_fred_rsps(); 2276 } else { 2277 load_current_idt(); 2278 } 2279 } 2280 2281 void __init cpu_init_replace_early_idt(void) 2282 { 2283 if (cpu_feature_enabled(X86_FEATURE_FRED)) 2284 cpu_init_fred_exceptions(); 2285 else 2286 idt_setup_early_pf(); 2287 } 2288 2289 /* 2290 * cpu_init() initializes state that is per-CPU. Some data is already 2291 * initialized (naturally) in the bootstrap process, such as the GDT. We 2292 * reload it nevertheless, this function acts as a 'CPU state barrier', 2293 * nothing should get across. 2294 */ 2295 void cpu_init(void) 2296 { 2297 struct task_struct *cur = current; 2298 int cpu = raw_smp_processor_id(); 2299 2300 #ifdef CONFIG_NUMA 2301 if (this_cpu_read(numa_node) == 0 && 2302 early_cpu_to_node(cpu) != NUMA_NO_NODE) 2303 set_numa_node(early_cpu_to_node(cpu)); 2304 #endif 2305 pr_debug("Initializing CPU#%d\n", cpu); 2306 2307 if (IS_ENABLED(CONFIG_X86_64) || cpu_feature_enabled(X86_FEATURE_VME) || 2308 boot_cpu_has(X86_FEATURE_TSC) || boot_cpu_has(X86_FEATURE_DE)) 2309 cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE); 2310 2311 if (IS_ENABLED(CONFIG_X86_64)) { 2312 loadsegment(fs, 0); 2313 memset(cur->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8); 2314 syscall_init(); 2315 2316 wrmsrl(MSR_FS_BASE, 0); 2317 wrmsrl(MSR_KERNEL_GS_BASE, 0); 2318 barrier(); 2319 2320 x2apic_setup(); 2321 2322 intel_posted_msi_init(); 2323 } 2324 2325 mmgrab(&init_mm); 2326 cur->active_mm = &init_mm; 2327 BUG_ON(cur->mm); 2328 initialize_tlbstate_and_flush(); 2329 enter_lazy_tlb(&init_mm, cur); 2330 2331 /* 2332 * sp0 points to the entry trampoline stack regardless of what task 2333 * is running. 2334 */ 2335 load_sp0((unsigned long)(cpu_entry_stack(cpu) + 1)); 2336 2337 load_mm_ldt(&init_mm); 2338 2339 clear_all_debug_regs(); 2340 dbg_restore_debug_regs(); 2341 2342 doublefault_init_cpu_tss(); 2343 2344 if (is_uv_system()) 2345 uv_cpu_init(); 2346 2347 load_fixmap_gdt(cpu); 2348 } 2349 2350 #ifdef CONFIG_MICROCODE_LATE_LOADING 2351 /** 2352 * store_cpu_caps() - Store a snapshot of CPU capabilities 2353 * @curr_info: Pointer where to store it 2354 * 2355 * Returns: None 2356 */ 2357 void store_cpu_caps(struct cpuinfo_x86 *curr_info) 2358 { 2359 /* Reload CPUID max function as it might've changed. */ 2360 curr_info->cpuid_level = cpuid_eax(0); 2361 2362 /* Copy all capability leafs and pick up the synthetic ones. */ 2363 memcpy(&curr_info->x86_capability, &boot_cpu_data.x86_capability, 2364 sizeof(curr_info->x86_capability)); 2365 2366 /* Get the hardware CPUID leafs */ 2367 get_cpu_cap(curr_info); 2368 } 2369 2370 /** 2371 * microcode_check() - Check if any CPU capabilities changed after an update. 2372 * @prev_info: CPU capabilities stored before an update. 2373 * 2374 * The microcode loader calls this upon late microcode load to recheck features, 2375 * only when microcode has been updated. Caller holds and CPU hotplug lock. 2376 * 2377 * Return: None 2378 */ 2379 void microcode_check(struct cpuinfo_x86 *prev_info) 2380 { 2381 struct cpuinfo_x86 curr_info; 2382 2383 perf_check_microcode(); 2384 2385 amd_check_microcode(); 2386 2387 store_cpu_caps(&curr_info); 2388 2389 if (!memcmp(&prev_info->x86_capability, &curr_info.x86_capability, 2390 sizeof(prev_info->x86_capability))) 2391 return; 2392 2393 pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n"); 2394 pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n"); 2395 } 2396 #endif 2397 2398 /* 2399 * Invoked from core CPU hotplug code after hotplug operations 2400 */ 2401 void arch_smt_update(void) 2402 { 2403 /* Handle the speculative execution misfeatures */ 2404 cpu_bugs_smt_update(); 2405 /* Check whether IPI broadcasting can be enabled */ 2406 apic_smt_update(); 2407 } 2408 2409 void __init arch_cpu_finalize_init(void) 2410 { 2411 struct cpuinfo_x86 *c = this_cpu_ptr(&cpu_info); 2412 2413 identify_boot_cpu(); 2414 2415 select_idle_routine(); 2416 2417 /* 2418 * identify_boot_cpu() initialized SMT support information, let the 2419 * core code know. 2420 */ 2421 cpu_smt_set_num_threads(__max_threads_per_core, __max_threads_per_core); 2422 2423 if (!IS_ENABLED(CONFIG_SMP)) { 2424 pr_info("CPU: "); 2425 print_cpu_info(&boot_cpu_data); 2426 } 2427 2428 cpu_select_mitigations(); 2429 2430 arch_smt_update(); 2431 2432 if (IS_ENABLED(CONFIG_X86_32)) { 2433 /* 2434 * Check whether this is a real i386 which is not longer 2435 * supported and fixup the utsname. 2436 */ 2437 if (boot_cpu_data.x86 < 4) 2438 panic("Kernel requires i486+ for 'invlpg' and other features"); 2439 2440 init_utsname()->machine[1] = 2441 '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86); 2442 } 2443 2444 /* 2445 * Must be before alternatives because it might set or clear 2446 * feature bits. 2447 */ 2448 fpu__init_system(); 2449 fpu__init_cpu(); 2450 2451 /* 2452 * Ensure that access to the per CPU representation has the initial 2453 * boot CPU configuration. 2454 */ 2455 *c = boot_cpu_data; 2456 c->initialized = true; 2457 2458 alternative_instructions(); 2459 2460 if (IS_ENABLED(CONFIG_X86_64)) { 2461 unsigned long USER_PTR_MAX = TASK_SIZE_MAX; 2462 2463 /* 2464 * Enable this when LAM is gated on LASS support 2465 if (cpu_feature_enabled(X86_FEATURE_LAM)) 2466 USER_PTR_MAX = (1ul << 63) - PAGE_SIZE; 2467 */ 2468 runtime_const_init(ptr, USER_PTR_MAX); 2469 2470 /* 2471 * Make sure the first 2MB area is not mapped by huge pages 2472 * There are typically fixed size MTRRs in there and overlapping 2473 * MTRRs into large pages causes slow downs. 2474 * 2475 * Right now we don't do that with gbpages because there seems 2476 * very little benefit for that case. 2477 */ 2478 if (!direct_gbpages) 2479 set_memory_4k((unsigned long)__va(0), 1); 2480 } else { 2481 fpu__init_check_bugs(); 2482 } 2483 2484 /* 2485 * This needs to be called before any devices perform DMA 2486 * operations that might use the SWIOTLB bounce buffers. It will 2487 * mark the bounce buffers as decrypted so that their usage will 2488 * not cause "plain-text" data to be decrypted when accessed. It 2489 * must be called after late_time_init() so that Hyper-V x86/x64 2490 * hypercalls work when the SWIOTLB bounce buffers are decrypted. 2491 */ 2492 mem_encrypt_init(); 2493 } 2494