1 /* cpu_feature_enabled() cannot be used this early */ 2 #define USE_EARLY_PGTABLE_L5 3 4 #include <linux/bootmem.h> 5 #include <linux/linkage.h> 6 #include <linux/bitops.h> 7 #include <linux/kernel.h> 8 #include <linux/export.h> 9 #include <linux/percpu.h> 10 #include <linux/string.h> 11 #include <linux/ctype.h> 12 #include <linux/delay.h> 13 #include <linux/sched/mm.h> 14 #include <linux/sched/clock.h> 15 #include <linux/sched/task.h> 16 #include <linux/init.h> 17 #include <linux/kprobes.h> 18 #include <linux/kgdb.h> 19 #include <linux/smp.h> 20 #include <linux/io.h> 21 #include <linux/syscore_ops.h> 22 23 #include <asm/stackprotector.h> 24 #include <asm/perf_event.h> 25 #include <asm/mmu_context.h> 26 #include <asm/archrandom.h> 27 #include <asm/hypervisor.h> 28 #include <asm/processor.h> 29 #include <asm/tlbflush.h> 30 #include <asm/debugreg.h> 31 #include <asm/sections.h> 32 #include <asm/vsyscall.h> 33 #include <linux/topology.h> 34 #include <linux/cpumask.h> 35 #include <asm/pgtable.h> 36 #include <linux/atomic.h> 37 #include <asm/proto.h> 38 #include <asm/setup.h> 39 #include <asm/apic.h> 40 #include <asm/desc.h> 41 #include <asm/fpu/internal.h> 42 #include <asm/mtrr.h> 43 #include <asm/hwcap2.h> 44 #include <linux/numa.h> 45 #include <asm/asm.h> 46 #include <asm/bugs.h> 47 #include <asm/cpu.h> 48 #include <asm/mce.h> 49 #include <asm/msr.h> 50 #include <asm/pat.h> 51 #include <asm/microcode.h> 52 #include <asm/microcode_intel.h> 53 #include <asm/intel-family.h> 54 #include <asm/cpu_device_id.h> 55 56 #ifdef CONFIG_X86_LOCAL_APIC 57 #include <asm/uv/uv.h> 58 #endif 59 60 #include "cpu.h" 61 62 u32 elf_hwcap2 __read_mostly; 63 64 /* all of these masks are initialized in setup_cpu_local_masks() */ 65 cpumask_var_t cpu_initialized_mask; 66 cpumask_var_t cpu_callout_mask; 67 cpumask_var_t cpu_callin_mask; 68 69 /* representing cpus for which sibling maps can be computed */ 70 cpumask_var_t cpu_sibling_setup_mask; 71 72 /* Number of siblings per CPU package */ 73 int smp_num_siblings = 1; 74 EXPORT_SYMBOL(smp_num_siblings); 75 76 /* Last level cache ID of each logical CPU */ 77 DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id) = BAD_APICID; 78 79 /* correctly size the local cpu masks */ 80 void __init setup_cpu_local_masks(void) 81 { 82 alloc_bootmem_cpumask_var(&cpu_initialized_mask); 83 alloc_bootmem_cpumask_var(&cpu_callin_mask); 84 alloc_bootmem_cpumask_var(&cpu_callout_mask); 85 alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask); 86 } 87 88 static void default_init(struct cpuinfo_x86 *c) 89 { 90 #ifdef CONFIG_X86_64 91 cpu_detect_cache_sizes(c); 92 #else 93 /* Not much we can do here... */ 94 /* Check if at least it has cpuid */ 95 if (c->cpuid_level == -1) { 96 /* No cpuid. It must be an ancient CPU */ 97 if (c->x86 == 4) 98 strcpy(c->x86_model_id, "486"); 99 else if (c->x86 == 3) 100 strcpy(c->x86_model_id, "386"); 101 } 102 #endif 103 } 104 105 static const struct cpu_dev default_cpu = { 106 .c_init = default_init, 107 .c_vendor = "Unknown", 108 .c_x86_vendor = X86_VENDOR_UNKNOWN, 109 }; 110 111 static const struct cpu_dev *this_cpu = &default_cpu; 112 113 DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = { 114 #ifdef CONFIG_X86_64 115 /* 116 * We need valid kernel segments for data and code in long mode too 117 * IRET will check the segment types kkeil 2000/10/28 118 * Also sysret mandates a special GDT layout 119 * 120 * TLS descriptors are currently at a different place compared to i386. 121 * Hopefully nobody expects them at a fixed place (Wine?) 122 */ 123 [GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(0xc09b, 0, 0xfffff), 124 [GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(0xa09b, 0, 0xfffff), 125 [GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(0xc093, 0, 0xfffff), 126 [GDT_ENTRY_DEFAULT_USER32_CS] = GDT_ENTRY_INIT(0xc0fb, 0, 0xfffff), 127 [GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(0xc0f3, 0, 0xfffff), 128 [GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(0xa0fb, 0, 0xfffff), 129 #else 130 [GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(0xc09a, 0, 0xfffff), 131 [GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff), 132 [GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(0xc0fa, 0, 0xfffff), 133 [GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(0xc0f2, 0, 0xfffff), 134 /* 135 * Segments used for calling PnP BIOS have byte granularity. 136 * They code segments and data segments have fixed 64k limits, 137 * the transfer segment sizes are set at run time. 138 */ 139 /* 32-bit code */ 140 [GDT_ENTRY_PNPBIOS_CS32] = GDT_ENTRY_INIT(0x409a, 0, 0xffff), 141 /* 16-bit code */ 142 [GDT_ENTRY_PNPBIOS_CS16] = GDT_ENTRY_INIT(0x009a, 0, 0xffff), 143 /* 16-bit data */ 144 [GDT_ENTRY_PNPBIOS_DS] = GDT_ENTRY_INIT(0x0092, 0, 0xffff), 145 /* 16-bit data */ 146 [GDT_ENTRY_PNPBIOS_TS1] = GDT_ENTRY_INIT(0x0092, 0, 0), 147 /* 16-bit data */ 148 [GDT_ENTRY_PNPBIOS_TS2] = GDT_ENTRY_INIT(0x0092, 0, 0), 149 /* 150 * The APM segments have byte granularity and their bases 151 * are set at run time. All have 64k limits. 152 */ 153 /* 32-bit code */ 154 [GDT_ENTRY_APMBIOS_BASE] = GDT_ENTRY_INIT(0x409a, 0, 0xffff), 155 /* 16-bit code */ 156 [GDT_ENTRY_APMBIOS_BASE+1] = GDT_ENTRY_INIT(0x009a, 0, 0xffff), 157 /* data */ 158 [GDT_ENTRY_APMBIOS_BASE+2] = GDT_ENTRY_INIT(0x4092, 0, 0xffff), 159 160 [GDT_ENTRY_ESPFIX_SS] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff), 161 [GDT_ENTRY_PERCPU] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff), 162 GDT_STACK_CANARY_INIT 163 #endif 164 } }; 165 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page); 166 167 static int __init x86_mpx_setup(char *s) 168 { 169 /* require an exact match without trailing characters */ 170 if (strlen(s)) 171 return 0; 172 173 /* do not emit a message if the feature is not present */ 174 if (!boot_cpu_has(X86_FEATURE_MPX)) 175 return 1; 176 177 setup_clear_cpu_cap(X86_FEATURE_MPX); 178 pr_info("nompx: Intel Memory Protection Extensions (MPX) disabled\n"); 179 return 1; 180 } 181 __setup("nompx", x86_mpx_setup); 182 183 #ifdef CONFIG_X86_64 184 static int __init x86_nopcid_setup(char *s) 185 { 186 /* nopcid doesn't accept parameters */ 187 if (s) 188 return -EINVAL; 189 190 /* do not emit a message if the feature is not present */ 191 if (!boot_cpu_has(X86_FEATURE_PCID)) 192 return 0; 193 194 setup_clear_cpu_cap(X86_FEATURE_PCID); 195 pr_info("nopcid: PCID feature disabled\n"); 196 return 0; 197 } 198 early_param("nopcid", x86_nopcid_setup); 199 #endif 200 201 static int __init x86_noinvpcid_setup(char *s) 202 { 203 /* noinvpcid doesn't accept parameters */ 204 if (s) 205 return -EINVAL; 206 207 /* do not emit a message if the feature is not present */ 208 if (!boot_cpu_has(X86_FEATURE_INVPCID)) 209 return 0; 210 211 setup_clear_cpu_cap(X86_FEATURE_INVPCID); 212 pr_info("noinvpcid: INVPCID feature disabled\n"); 213 return 0; 214 } 215 early_param("noinvpcid", x86_noinvpcid_setup); 216 217 #ifdef CONFIG_X86_32 218 static int cachesize_override = -1; 219 static int disable_x86_serial_nr = 1; 220 221 static int __init cachesize_setup(char *str) 222 { 223 get_option(&str, &cachesize_override); 224 return 1; 225 } 226 __setup("cachesize=", cachesize_setup); 227 228 static int __init x86_sep_setup(char *s) 229 { 230 setup_clear_cpu_cap(X86_FEATURE_SEP); 231 return 1; 232 } 233 __setup("nosep", x86_sep_setup); 234 235 /* Standard macro to see if a specific flag is changeable */ 236 static inline int flag_is_changeable_p(u32 flag) 237 { 238 u32 f1, f2; 239 240 /* 241 * Cyrix and IDT cpus allow disabling of CPUID 242 * so the code below may return different results 243 * when it is executed before and after enabling 244 * the CPUID. Add "volatile" to not allow gcc to 245 * optimize the subsequent calls to this function. 246 */ 247 asm volatile ("pushfl \n\t" 248 "pushfl \n\t" 249 "popl %0 \n\t" 250 "movl %0, %1 \n\t" 251 "xorl %2, %0 \n\t" 252 "pushl %0 \n\t" 253 "popfl \n\t" 254 "pushfl \n\t" 255 "popl %0 \n\t" 256 "popfl \n\t" 257 258 : "=&r" (f1), "=&r" (f2) 259 : "ir" (flag)); 260 261 return ((f1^f2) & flag) != 0; 262 } 263 264 /* Probe for the CPUID instruction */ 265 int have_cpuid_p(void) 266 { 267 return flag_is_changeable_p(X86_EFLAGS_ID); 268 } 269 270 static void squash_the_stupid_serial_number(struct cpuinfo_x86 *c) 271 { 272 unsigned long lo, hi; 273 274 if (!cpu_has(c, X86_FEATURE_PN) || !disable_x86_serial_nr) 275 return; 276 277 /* Disable processor serial number: */ 278 279 rdmsr(MSR_IA32_BBL_CR_CTL, lo, hi); 280 lo |= 0x200000; 281 wrmsr(MSR_IA32_BBL_CR_CTL, lo, hi); 282 283 pr_notice("CPU serial number disabled.\n"); 284 clear_cpu_cap(c, X86_FEATURE_PN); 285 286 /* Disabling the serial number may affect the cpuid level */ 287 c->cpuid_level = cpuid_eax(0); 288 } 289 290 static int __init x86_serial_nr_setup(char *s) 291 { 292 disable_x86_serial_nr = 0; 293 return 1; 294 } 295 __setup("serialnumber", x86_serial_nr_setup); 296 #else 297 static inline int flag_is_changeable_p(u32 flag) 298 { 299 return 1; 300 } 301 static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c) 302 { 303 } 304 #endif 305 306 static __init int setup_disable_smep(char *arg) 307 { 308 setup_clear_cpu_cap(X86_FEATURE_SMEP); 309 /* Check for things that depend on SMEP being enabled: */ 310 check_mpx_erratum(&boot_cpu_data); 311 return 1; 312 } 313 __setup("nosmep", setup_disable_smep); 314 315 static __always_inline void setup_smep(struct cpuinfo_x86 *c) 316 { 317 if (cpu_has(c, X86_FEATURE_SMEP)) 318 cr4_set_bits(X86_CR4_SMEP); 319 } 320 321 static __init int setup_disable_smap(char *arg) 322 { 323 setup_clear_cpu_cap(X86_FEATURE_SMAP); 324 return 1; 325 } 326 __setup("nosmap", setup_disable_smap); 327 328 static __always_inline void setup_smap(struct cpuinfo_x86 *c) 329 { 330 unsigned long eflags = native_save_fl(); 331 332 /* This should have been cleared long ago */ 333 BUG_ON(eflags & X86_EFLAGS_AC); 334 335 if (cpu_has(c, X86_FEATURE_SMAP)) { 336 #ifdef CONFIG_X86_SMAP 337 cr4_set_bits(X86_CR4_SMAP); 338 #else 339 cr4_clear_bits(X86_CR4_SMAP); 340 #endif 341 } 342 } 343 344 static __always_inline void setup_umip(struct cpuinfo_x86 *c) 345 { 346 /* Check the boot processor, plus build option for UMIP. */ 347 if (!cpu_feature_enabled(X86_FEATURE_UMIP)) 348 goto out; 349 350 /* Check the current processor's cpuid bits. */ 351 if (!cpu_has(c, X86_FEATURE_UMIP)) 352 goto out; 353 354 cr4_set_bits(X86_CR4_UMIP); 355 356 pr_info("x86/cpu: Activated the Intel User Mode Instruction Prevention (UMIP) CPU feature\n"); 357 358 return; 359 360 out: 361 /* 362 * Make sure UMIP is disabled in case it was enabled in a 363 * previous boot (e.g., via kexec). 364 */ 365 cr4_clear_bits(X86_CR4_UMIP); 366 } 367 368 /* 369 * Protection Keys are not available in 32-bit mode. 370 */ 371 static bool pku_disabled; 372 373 static __always_inline void setup_pku(struct cpuinfo_x86 *c) 374 { 375 /* check the boot processor, plus compile options for PKU: */ 376 if (!cpu_feature_enabled(X86_FEATURE_PKU)) 377 return; 378 /* checks the actual processor's cpuid bits: */ 379 if (!cpu_has(c, X86_FEATURE_PKU)) 380 return; 381 if (pku_disabled) 382 return; 383 384 cr4_set_bits(X86_CR4_PKE); 385 /* 386 * Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE 387 * cpuid bit to be set. We need to ensure that we 388 * update that bit in this CPU's "cpu_info". 389 */ 390 get_cpu_cap(c); 391 } 392 393 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 394 static __init int setup_disable_pku(char *arg) 395 { 396 /* 397 * Do not clear the X86_FEATURE_PKU bit. All of the 398 * runtime checks are against OSPKE so clearing the 399 * bit does nothing. 400 * 401 * This way, we will see "pku" in cpuinfo, but not 402 * "ospke", which is exactly what we want. It shows 403 * that the CPU has PKU, but the OS has not enabled it. 404 * This happens to be exactly how a system would look 405 * if we disabled the config option. 406 */ 407 pr_info("x86: 'nopku' specified, disabling Memory Protection Keys\n"); 408 pku_disabled = true; 409 return 1; 410 } 411 __setup("nopku", setup_disable_pku); 412 #endif /* CONFIG_X86_64 */ 413 414 /* 415 * Some CPU features depend on higher CPUID levels, which may not always 416 * be available due to CPUID level capping or broken virtualization 417 * software. Add those features to this table to auto-disable them. 418 */ 419 struct cpuid_dependent_feature { 420 u32 feature; 421 u32 level; 422 }; 423 424 static const struct cpuid_dependent_feature 425 cpuid_dependent_features[] = { 426 { X86_FEATURE_MWAIT, 0x00000005 }, 427 { X86_FEATURE_DCA, 0x00000009 }, 428 { X86_FEATURE_XSAVE, 0x0000000d }, 429 { 0, 0 } 430 }; 431 432 static void filter_cpuid_features(struct cpuinfo_x86 *c, bool warn) 433 { 434 const struct cpuid_dependent_feature *df; 435 436 for (df = cpuid_dependent_features; df->feature; df++) { 437 438 if (!cpu_has(c, df->feature)) 439 continue; 440 /* 441 * Note: cpuid_level is set to -1 if unavailable, but 442 * extended_extended_level is set to 0 if unavailable 443 * and the legitimate extended levels are all negative 444 * when signed; hence the weird messing around with 445 * signs here... 446 */ 447 if (!((s32)df->level < 0 ? 448 (u32)df->level > (u32)c->extended_cpuid_level : 449 (s32)df->level > (s32)c->cpuid_level)) 450 continue; 451 452 clear_cpu_cap(c, df->feature); 453 if (!warn) 454 continue; 455 456 pr_warn("CPU: CPU feature " X86_CAP_FMT " disabled, no CPUID level 0x%x\n", 457 x86_cap_flag(df->feature), df->level); 458 } 459 } 460 461 /* 462 * Naming convention should be: <Name> [(<Codename>)] 463 * This table only is used unless init_<vendor>() below doesn't set it; 464 * in particular, if CPUID levels 0x80000002..4 are supported, this 465 * isn't used 466 */ 467 468 /* Look up CPU names by table lookup. */ 469 static const char *table_lookup_model(struct cpuinfo_x86 *c) 470 { 471 #ifdef CONFIG_X86_32 472 const struct legacy_cpu_model_info *info; 473 474 if (c->x86_model >= 16) 475 return NULL; /* Range check */ 476 477 if (!this_cpu) 478 return NULL; 479 480 info = this_cpu->legacy_models; 481 482 while (info->family) { 483 if (info->family == c->x86) 484 return info->model_names[c->x86_model]; 485 info++; 486 } 487 #endif 488 return NULL; /* Not found */ 489 } 490 491 __u32 cpu_caps_cleared[NCAPINTS + NBUGINTS]; 492 __u32 cpu_caps_set[NCAPINTS + NBUGINTS]; 493 494 void load_percpu_segment(int cpu) 495 { 496 #ifdef CONFIG_X86_32 497 loadsegment(fs, __KERNEL_PERCPU); 498 #else 499 __loadsegment_simple(gs, 0); 500 wrmsrl(MSR_GS_BASE, cpu_kernelmode_gs_base(cpu)); 501 #endif 502 load_stack_canary_segment(); 503 } 504 505 #ifdef CONFIG_X86_32 506 /* The 32-bit entry code needs to find cpu_entry_area. */ 507 DEFINE_PER_CPU(struct cpu_entry_area *, cpu_entry_area); 508 #endif 509 510 #ifdef CONFIG_X86_64 511 /* 512 * Special IST stacks which the CPU switches to when it calls 513 * an IST-marked descriptor entry. Up to 7 stacks (hardware 514 * limit), all of them are 4K, except the debug stack which 515 * is 8K. 516 */ 517 static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = { 518 [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ, 519 [DEBUG_STACK - 1] = DEBUG_STKSZ 520 }; 521 #endif 522 523 /* Load the original GDT from the per-cpu structure */ 524 void load_direct_gdt(int cpu) 525 { 526 struct desc_ptr gdt_descr; 527 528 gdt_descr.address = (long)get_cpu_gdt_rw(cpu); 529 gdt_descr.size = GDT_SIZE - 1; 530 load_gdt(&gdt_descr); 531 } 532 EXPORT_SYMBOL_GPL(load_direct_gdt); 533 534 /* Load a fixmap remapping of the per-cpu GDT */ 535 void load_fixmap_gdt(int cpu) 536 { 537 struct desc_ptr gdt_descr; 538 539 gdt_descr.address = (long)get_cpu_gdt_ro(cpu); 540 gdt_descr.size = GDT_SIZE - 1; 541 load_gdt(&gdt_descr); 542 } 543 EXPORT_SYMBOL_GPL(load_fixmap_gdt); 544 545 /* 546 * Current gdt points %fs at the "master" per-cpu area: after this, 547 * it's on the real one. 548 */ 549 void switch_to_new_gdt(int cpu) 550 { 551 /* Load the original GDT */ 552 load_direct_gdt(cpu); 553 /* Reload the per-cpu base */ 554 load_percpu_segment(cpu); 555 } 556 557 static const struct cpu_dev *cpu_devs[X86_VENDOR_NUM] = {}; 558 559 static void get_model_name(struct cpuinfo_x86 *c) 560 { 561 unsigned int *v; 562 char *p, *q, *s; 563 564 if (c->extended_cpuid_level < 0x80000004) 565 return; 566 567 v = (unsigned int *)c->x86_model_id; 568 cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]); 569 cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]); 570 cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]); 571 c->x86_model_id[48] = 0; 572 573 /* Trim whitespace */ 574 p = q = s = &c->x86_model_id[0]; 575 576 while (*p == ' ') 577 p++; 578 579 while (*p) { 580 /* Note the last non-whitespace index */ 581 if (!isspace(*p)) 582 s = q; 583 584 *q++ = *p++; 585 } 586 587 *(s + 1) = '\0'; 588 } 589 590 void detect_num_cpu_cores(struct cpuinfo_x86 *c) 591 { 592 unsigned int eax, ebx, ecx, edx; 593 594 c->x86_max_cores = 1; 595 if (!IS_ENABLED(CONFIG_SMP) || c->cpuid_level < 4) 596 return; 597 598 cpuid_count(4, 0, &eax, &ebx, &ecx, &edx); 599 if (eax & 0x1f) 600 c->x86_max_cores = (eax >> 26) + 1; 601 } 602 603 void cpu_detect_cache_sizes(struct cpuinfo_x86 *c) 604 { 605 unsigned int n, dummy, ebx, ecx, edx, l2size; 606 607 n = c->extended_cpuid_level; 608 609 if (n >= 0x80000005) { 610 cpuid(0x80000005, &dummy, &ebx, &ecx, &edx); 611 c->x86_cache_size = (ecx>>24) + (edx>>24); 612 #ifdef CONFIG_X86_64 613 /* On K8 L1 TLB is inclusive, so don't count it */ 614 c->x86_tlbsize = 0; 615 #endif 616 } 617 618 if (n < 0x80000006) /* Some chips just has a large L1. */ 619 return; 620 621 cpuid(0x80000006, &dummy, &ebx, &ecx, &edx); 622 l2size = ecx >> 16; 623 624 #ifdef CONFIG_X86_64 625 c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff); 626 #else 627 /* do processor-specific cache resizing */ 628 if (this_cpu->legacy_cache_size) 629 l2size = this_cpu->legacy_cache_size(c, l2size); 630 631 /* Allow user to override all this if necessary. */ 632 if (cachesize_override != -1) 633 l2size = cachesize_override; 634 635 if (l2size == 0) 636 return; /* Again, no L2 cache is possible */ 637 #endif 638 639 c->x86_cache_size = l2size; 640 } 641 642 u16 __read_mostly tlb_lli_4k[NR_INFO]; 643 u16 __read_mostly tlb_lli_2m[NR_INFO]; 644 u16 __read_mostly tlb_lli_4m[NR_INFO]; 645 u16 __read_mostly tlb_lld_4k[NR_INFO]; 646 u16 __read_mostly tlb_lld_2m[NR_INFO]; 647 u16 __read_mostly tlb_lld_4m[NR_INFO]; 648 u16 __read_mostly tlb_lld_1g[NR_INFO]; 649 650 static void cpu_detect_tlb(struct cpuinfo_x86 *c) 651 { 652 if (this_cpu->c_detect_tlb) 653 this_cpu->c_detect_tlb(c); 654 655 pr_info("Last level iTLB entries: 4KB %d, 2MB %d, 4MB %d\n", 656 tlb_lli_4k[ENTRIES], tlb_lli_2m[ENTRIES], 657 tlb_lli_4m[ENTRIES]); 658 659 pr_info("Last level dTLB entries: 4KB %d, 2MB %d, 4MB %d, 1GB %d\n", 660 tlb_lld_4k[ENTRIES], tlb_lld_2m[ENTRIES], 661 tlb_lld_4m[ENTRIES], tlb_lld_1g[ENTRIES]); 662 } 663 664 int detect_ht_early(struct cpuinfo_x86 *c) 665 { 666 #ifdef CONFIG_SMP 667 u32 eax, ebx, ecx, edx; 668 669 if (!cpu_has(c, X86_FEATURE_HT)) 670 return -1; 671 672 if (cpu_has(c, X86_FEATURE_CMP_LEGACY)) 673 return -1; 674 675 if (cpu_has(c, X86_FEATURE_XTOPOLOGY)) 676 return -1; 677 678 cpuid(1, &eax, &ebx, &ecx, &edx); 679 680 smp_num_siblings = (ebx & 0xff0000) >> 16; 681 if (smp_num_siblings == 1) 682 pr_info_once("CPU0: Hyper-Threading is disabled\n"); 683 #endif 684 return 0; 685 } 686 687 void detect_ht(struct cpuinfo_x86 *c) 688 { 689 #ifdef CONFIG_SMP 690 int index_msb, core_bits; 691 692 if (detect_ht_early(c) < 0) 693 return; 694 695 index_msb = get_count_order(smp_num_siblings); 696 c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb); 697 698 smp_num_siblings = smp_num_siblings / c->x86_max_cores; 699 700 index_msb = get_count_order(smp_num_siblings); 701 702 core_bits = get_count_order(c->x86_max_cores); 703 704 c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, index_msb) & 705 ((1 << core_bits) - 1); 706 #endif 707 } 708 709 static void get_cpu_vendor(struct cpuinfo_x86 *c) 710 { 711 char *v = c->x86_vendor_id; 712 int i; 713 714 for (i = 0; i < X86_VENDOR_NUM; i++) { 715 if (!cpu_devs[i]) 716 break; 717 718 if (!strcmp(v, cpu_devs[i]->c_ident[0]) || 719 (cpu_devs[i]->c_ident[1] && 720 !strcmp(v, cpu_devs[i]->c_ident[1]))) { 721 722 this_cpu = cpu_devs[i]; 723 c->x86_vendor = this_cpu->c_x86_vendor; 724 return; 725 } 726 } 727 728 pr_err_once("CPU: vendor_id '%s' unknown, using generic init.\n" \ 729 "CPU: Your system may be unstable.\n", v); 730 731 c->x86_vendor = X86_VENDOR_UNKNOWN; 732 this_cpu = &default_cpu; 733 } 734 735 void cpu_detect(struct cpuinfo_x86 *c) 736 { 737 /* Get vendor name */ 738 cpuid(0x00000000, (unsigned int *)&c->cpuid_level, 739 (unsigned int *)&c->x86_vendor_id[0], 740 (unsigned int *)&c->x86_vendor_id[8], 741 (unsigned int *)&c->x86_vendor_id[4]); 742 743 c->x86 = 4; 744 /* Intel-defined flags: level 0x00000001 */ 745 if (c->cpuid_level >= 0x00000001) { 746 u32 junk, tfms, cap0, misc; 747 748 cpuid(0x00000001, &tfms, &misc, &junk, &cap0); 749 c->x86 = x86_family(tfms); 750 c->x86_model = x86_model(tfms); 751 c->x86_stepping = x86_stepping(tfms); 752 753 if (cap0 & (1<<19)) { 754 c->x86_clflush_size = ((misc >> 8) & 0xff) * 8; 755 c->x86_cache_alignment = c->x86_clflush_size; 756 } 757 } 758 } 759 760 static void apply_forced_caps(struct cpuinfo_x86 *c) 761 { 762 int i; 763 764 for (i = 0; i < NCAPINTS + NBUGINTS; i++) { 765 c->x86_capability[i] &= ~cpu_caps_cleared[i]; 766 c->x86_capability[i] |= cpu_caps_set[i]; 767 } 768 } 769 770 static void init_speculation_control(struct cpuinfo_x86 *c) 771 { 772 /* 773 * The Intel SPEC_CTRL CPUID bit implies IBRS and IBPB support, 774 * and they also have a different bit for STIBP support. Also, 775 * a hypervisor might have set the individual AMD bits even on 776 * Intel CPUs, for finer-grained selection of what's available. 777 */ 778 if (cpu_has(c, X86_FEATURE_SPEC_CTRL)) { 779 set_cpu_cap(c, X86_FEATURE_IBRS); 780 set_cpu_cap(c, X86_FEATURE_IBPB); 781 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 782 } 783 784 if (cpu_has(c, X86_FEATURE_INTEL_STIBP)) 785 set_cpu_cap(c, X86_FEATURE_STIBP); 786 787 if (cpu_has(c, X86_FEATURE_SPEC_CTRL_SSBD) || 788 cpu_has(c, X86_FEATURE_VIRT_SSBD)) 789 set_cpu_cap(c, X86_FEATURE_SSBD); 790 791 if (cpu_has(c, X86_FEATURE_AMD_IBRS)) { 792 set_cpu_cap(c, X86_FEATURE_IBRS); 793 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 794 } 795 796 if (cpu_has(c, X86_FEATURE_AMD_IBPB)) 797 set_cpu_cap(c, X86_FEATURE_IBPB); 798 799 if (cpu_has(c, X86_FEATURE_AMD_STIBP)) { 800 set_cpu_cap(c, X86_FEATURE_STIBP); 801 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 802 } 803 804 if (cpu_has(c, X86_FEATURE_AMD_SSBD)) { 805 set_cpu_cap(c, X86_FEATURE_SSBD); 806 set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); 807 clear_cpu_cap(c, X86_FEATURE_VIRT_SSBD); 808 } 809 } 810 811 void get_cpu_cap(struct cpuinfo_x86 *c) 812 { 813 u32 eax, ebx, ecx, edx; 814 815 /* Intel-defined flags: level 0x00000001 */ 816 if (c->cpuid_level >= 0x00000001) { 817 cpuid(0x00000001, &eax, &ebx, &ecx, &edx); 818 819 c->x86_capability[CPUID_1_ECX] = ecx; 820 c->x86_capability[CPUID_1_EDX] = edx; 821 } 822 823 /* Thermal and Power Management Leaf: level 0x00000006 (eax) */ 824 if (c->cpuid_level >= 0x00000006) 825 c->x86_capability[CPUID_6_EAX] = cpuid_eax(0x00000006); 826 827 /* Additional Intel-defined flags: level 0x00000007 */ 828 if (c->cpuid_level >= 0x00000007) { 829 cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx); 830 c->x86_capability[CPUID_7_0_EBX] = ebx; 831 c->x86_capability[CPUID_7_ECX] = ecx; 832 c->x86_capability[CPUID_7_EDX] = edx; 833 } 834 835 /* Extended state features: level 0x0000000d */ 836 if (c->cpuid_level >= 0x0000000d) { 837 cpuid_count(0x0000000d, 1, &eax, &ebx, &ecx, &edx); 838 839 c->x86_capability[CPUID_D_1_EAX] = eax; 840 } 841 842 /* Additional Intel-defined flags: level 0x0000000F */ 843 if (c->cpuid_level >= 0x0000000F) { 844 845 /* QoS sub-leaf, EAX=0Fh, ECX=0 */ 846 cpuid_count(0x0000000F, 0, &eax, &ebx, &ecx, &edx); 847 c->x86_capability[CPUID_F_0_EDX] = edx; 848 849 if (cpu_has(c, X86_FEATURE_CQM_LLC)) { 850 /* will be overridden if occupancy monitoring exists */ 851 c->x86_cache_max_rmid = ebx; 852 853 /* QoS sub-leaf, EAX=0Fh, ECX=1 */ 854 cpuid_count(0x0000000F, 1, &eax, &ebx, &ecx, &edx); 855 c->x86_capability[CPUID_F_1_EDX] = edx; 856 857 if ((cpu_has(c, X86_FEATURE_CQM_OCCUP_LLC)) || 858 ((cpu_has(c, X86_FEATURE_CQM_MBM_TOTAL)) || 859 (cpu_has(c, X86_FEATURE_CQM_MBM_LOCAL)))) { 860 c->x86_cache_max_rmid = ecx; 861 c->x86_cache_occ_scale = ebx; 862 } 863 } else { 864 c->x86_cache_max_rmid = -1; 865 c->x86_cache_occ_scale = -1; 866 } 867 } 868 869 /* AMD-defined flags: level 0x80000001 */ 870 eax = cpuid_eax(0x80000000); 871 c->extended_cpuid_level = eax; 872 873 if ((eax & 0xffff0000) == 0x80000000) { 874 if (eax >= 0x80000001) { 875 cpuid(0x80000001, &eax, &ebx, &ecx, &edx); 876 877 c->x86_capability[CPUID_8000_0001_ECX] = ecx; 878 c->x86_capability[CPUID_8000_0001_EDX] = edx; 879 } 880 } 881 882 if (c->extended_cpuid_level >= 0x80000007) { 883 cpuid(0x80000007, &eax, &ebx, &ecx, &edx); 884 885 c->x86_capability[CPUID_8000_0007_EBX] = ebx; 886 c->x86_power = edx; 887 } 888 889 if (c->extended_cpuid_level >= 0x80000008) { 890 cpuid(0x80000008, &eax, &ebx, &ecx, &edx); 891 c->x86_capability[CPUID_8000_0008_EBX] = ebx; 892 } 893 894 if (c->extended_cpuid_level >= 0x8000000a) 895 c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a); 896 897 init_scattered_cpuid_features(c); 898 init_speculation_control(c); 899 900 /* 901 * Clear/Set all flags overridden by options, after probe. 902 * This needs to happen each time we re-probe, which may happen 903 * several times during CPU initialization. 904 */ 905 apply_forced_caps(c); 906 } 907 908 void get_cpu_address_sizes(struct cpuinfo_x86 *c) 909 { 910 u32 eax, ebx, ecx, edx; 911 912 if (c->extended_cpuid_level >= 0x80000008) { 913 cpuid(0x80000008, &eax, &ebx, &ecx, &edx); 914 915 c->x86_virt_bits = (eax >> 8) & 0xff; 916 c->x86_phys_bits = eax & 0xff; 917 } 918 #ifdef CONFIG_X86_32 919 else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36)) 920 c->x86_phys_bits = 36; 921 #endif 922 c->x86_cache_bits = c->x86_phys_bits; 923 } 924 925 static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c) 926 { 927 #ifdef CONFIG_X86_32 928 int i; 929 930 /* 931 * First of all, decide if this is a 486 or higher 932 * It's a 486 if we can modify the AC flag 933 */ 934 if (flag_is_changeable_p(X86_EFLAGS_AC)) 935 c->x86 = 4; 936 else 937 c->x86 = 3; 938 939 for (i = 0; i < X86_VENDOR_NUM; i++) 940 if (cpu_devs[i] && cpu_devs[i]->c_identify) { 941 c->x86_vendor_id[0] = 0; 942 cpu_devs[i]->c_identify(c); 943 if (c->x86_vendor_id[0]) { 944 get_cpu_vendor(c); 945 break; 946 } 947 } 948 #endif 949 } 950 951 static const __initconst struct x86_cpu_id cpu_no_speculation[] = { 952 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CEDARVIEW, X86_FEATURE_ANY }, 953 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CLOVERVIEW, X86_FEATURE_ANY }, 954 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_LINCROFT, X86_FEATURE_ANY }, 955 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PENWELL, X86_FEATURE_ANY }, 956 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PINEVIEW, X86_FEATURE_ANY }, 957 { X86_VENDOR_CENTAUR, 5 }, 958 { X86_VENDOR_INTEL, 5 }, 959 { X86_VENDOR_NSC, 5 }, 960 { X86_VENDOR_ANY, 4 }, 961 {} 962 }; 963 964 static const __initconst struct x86_cpu_id cpu_no_meltdown[] = { 965 { X86_VENDOR_AMD }, 966 {} 967 }; 968 969 /* Only list CPUs which speculate but are non susceptible to SSB */ 970 static const __initconst struct x86_cpu_id cpu_no_spec_store_bypass[] = { 971 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT1 }, 972 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_AIRMONT }, 973 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT2 }, 974 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_MERRIFIELD }, 975 { X86_VENDOR_INTEL, 6, INTEL_FAM6_CORE_YONAH }, 976 { X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNL }, 977 { X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNM }, 978 { X86_VENDOR_AMD, 0x12, }, 979 { X86_VENDOR_AMD, 0x11, }, 980 { X86_VENDOR_AMD, 0x10, }, 981 { X86_VENDOR_AMD, 0xf, }, 982 {} 983 }; 984 985 static const __initconst struct x86_cpu_id cpu_no_l1tf[] = { 986 /* in addition to cpu_no_speculation */ 987 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT1 }, 988 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT2 }, 989 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_AIRMONT }, 990 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_MERRIFIELD }, 991 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_MOOREFIELD }, 992 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_GOLDMONT }, 993 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_DENVERTON }, 994 { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_GEMINI_LAKE }, 995 { X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNL }, 996 { X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNM }, 997 {} 998 }; 999 1000 static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) 1001 { 1002 u64 ia32_cap = 0; 1003 1004 if (x86_match_cpu(cpu_no_speculation)) 1005 return; 1006 1007 setup_force_cpu_bug(X86_BUG_SPECTRE_V1); 1008 setup_force_cpu_bug(X86_BUG_SPECTRE_V2); 1009 1010 if (cpu_has(c, X86_FEATURE_ARCH_CAPABILITIES)) 1011 rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap); 1012 1013 if (!x86_match_cpu(cpu_no_spec_store_bypass) && 1014 !(ia32_cap & ARCH_CAP_SSB_NO) && 1015 !cpu_has(c, X86_FEATURE_AMD_SSB_NO)) 1016 setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS); 1017 1018 if (ia32_cap & ARCH_CAP_IBRS_ALL) 1019 setup_force_cpu_cap(X86_FEATURE_IBRS_ENHANCED); 1020 1021 if (x86_match_cpu(cpu_no_meltdown)) 1022 return; 1023 1024 /* Rogue Data Cache Load? No! */ 1025 if (ia32_cap & ARCH_CAP_RDCL_NO) 1026 return; 1027 1028 setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN); 1029 1030 if (x86_match_cpu(cpu_no_l1tf)) 1031 return; 1032 1033 setup_force_cpu_bug(X86_BUG_L1TF); 1034 } 1035 1036 /* 1037 * The NOPL instruction is supposed to exist on all CPUs of family >= 6; 1038 * unfortunately, that's not true in practice because of early VIA 1039 * chips and (more importantly) broken virtualizers that are not easy 1040 * to detect. In the latter case it doesn't even *fail* reliably, so 1041 * probing for it doesn't even work. Disable it completely on 32-bit 1042 * unless we can find a reliable way to detect all the broken cases. 1043 * Enable it explicitly on 64-bit for non-constant inputs of cpu_has(). 1044 */ 1045 static void detect_nopl(void) 1046 { 1047 #ifdef CONFIG_X86_32 1048 setup_clear_cpu_cap(X86_FEATURE_NOPL); 1049 #else 1050 setup_force_cpu_cap(X86_FEATURE_NOPL); 1051 #endif 1052 } 1053 1054 /* 1055 * Do minimum CPU detection early. 1056 * Fields really needed: vendor, cpuid_level, family, model, mask, 1057 * cache alignment. 1058 * The others are not touched to avoid unwanted side effects. 1059 * 1060 * WARNING: this function is only called on the boot CPU. Don't add code 1061 * here that is supposed to run on all CPUs. 1062 */ 1063 static void __init early_identify_cpu(struct cpuinfo_x86 *c) 1064 { 1065 #ifdef CONFIG_X86_64 1066 c->x86_clflush_size = 64; 1067 c->x86_phys_bits = 36; 1068 c->x86_virt_bits = 48; 1069 #else 1070 c->x86_clflush_size = 32; 1071 c->x86_phys_bits = 32; 1072 c->x86_virt_bits = 32; 1073 #endif 1074 c->x86_cache_alignment = c->x86_clflush_size; 1075 1076 memset(&c->x86_capability, 0, sizeof c->x86_capability); 1077 c->extended_cpuid_level = 0; 1078 1079 /* cyrix could have cpuid enabled via c_identify()*/ 1080 if (have_cpuid_p()) { 1081 cpu_detect(c); 1082 get_cpu_vendor(c); 1083 get_cpu_cap(c); 1084 get_cpu_address_sizes(c); 1085 setup_force_cpu_cap(X86_FEATURE_CPUID); 1086 1087 if (this_cpu->c_early_init) 1088 this_cpu->c_early_init(c); 1089 1090 c->cpu_index = 0; 1091 filter_cpuid_features(c, false); 1092 1093 if (this_cpu->c_bsp_init) 1094 this_cpu->c_bsp_init(c); 1095 } else { 1096 identify_cpu_without_cpuid(c); 1097 setup_clear_cpu_cap(X86_FEATURE_CPUID); 1098 } 1099 1100 setup_force_cpu_cap(X86_FEATURE_ALWAYS); 1101 1102 cpu_set_bug_bits(c); 1103 1104 fpu__init_system(c); 1105 1106 #ifdef CONFIG_X86_32 1107 /* 1108 * Regardless of whether PCID is enumerated, the SDM says 1109 * that it can't be enabled in 32-bit mode. 1110 */ 1111 setup_clear_cpu_cap(X86_FEATURE_PCID); 1112 #endif 1113 1114 /* 1115 * Later in the boot process pgtable_l5_enabled() relies on 1116 * cpu_feature_enabled(X86_FEATURE_LA57). If 5-level paging is not 1117 * enabled by this point we need to clear the feature bit to avoid 1118 * false-positives at the later stage. 1119 * 1120 * pgtable_l5_enabled() can be false here for several reasons: 1121 * - 5-level paging is disabled compile-time; 1122 * - it's 32-bit kernel; 1123 * - machine doesn't support 5-level paging; 1124 * - user specified 'no5lvl' in kernel command line. 1125 */ 1126 if (!pgtable_l5_enabled()) 1127 setup_clear_cpu_cap(X86_FEATURE_LA57); 1128 1129 detect_nopl(); 1130 } 1131 1132 void __init early_cpu_init(void) 1133 { 1134 const struct cpu_dev *const *cdev; 1135 int count = 0; 1136 1137 #ifdef CONFIG_PROCESSOR_SELECT 1138 pr_info("KERNEL supported cpus:\n"); 1139 #endif 1140 1141 for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) { 1142 const struct cpu_dev *cpudev = *cdev; 1143 1144 if (count >= X86_VENDOR_NUM) 1145 break; 1146 cpu_devs[count] = cpudev; 1147 count++; 1148 1149 #ifdef CONFIG_PROCESSOR_SELECT 1150 { 1151 unsigned int j; 1152 1153 for (j = 0; j < 2; j++) { 1154 if (!cpudev->c_ident[j]) 1155 continue; 1156 pr_info(" %s %s\n", cpudev->c_vendor, 1157 cpudev->c_ident[j]); 1158 } 1159 } 1160 #endif 1161 } 1162 early_identify_cpu(&boot_cpu_data); 1163 } 1164 1165 static void detect_null_seg_behavior(struct cpuinfo_x86 *c) 1166 { 1167 #ifdef CONFIG_X86_64 1168 /* 1169 * Empirically, writing zero to a segment selector on AMD does 1170 * not clear the base, whereas writing zero to a segment 1171 * selector on Intel does clear the base. Intel's behavior 1172 * allows slightly faster context switches in the common case 1173 * where GS is unused by the prev and next threads. 1174 * 1175 * Since neither vendor documents this anywhere that I can see, 1176 * detect it directly instead of hardcoding the choice by 1177 * vendor. 1178 * 1179 * I've designated AMD's behavior as the "bug" because it's 1180 * counterintuitive and less friendly. 1181 */ 1182 1183 unsigned long old_base, tmp; 1184 rdmsrl(MSR_FS_BASE, old_base); 1185 wrmsrl(MSR_FS_BASE, 1); 1186 loadsegment(fs, 0); 1187 rdmsrl(MSR_FS_BASE, tmp); 1188 if (tmp != 0) 1189 set_cpu_bug(c, X86_BUG_NULL_SEG); 1190 wrmsrl(MSR_FS_BASE, old_base); 1191 #endif 1192 } 1193 1194 static void generic_identify(struct cpuinfo_x86 *c) 1195 { 1196 c->extended_cpuid_level = 0; 1197 1198 if (!have_cpuid_p()) 1199 identify_cpu_without_cpuid(c); 1200 1201 /* cyrix could have cpuid enabled via c_identify()*/ 1202 if (!have_cpuid_p()) 1203 return; 1204 1205 cpu_detect(c); 1206 1207 get_cpu_vendor(c); 1208 1209 get_cpu_cap(c); 1210 1211 get_cpu_address_sizes(c); 1212 1213 if (c->cpuid_level >= 0x00000001) { 1214 c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xFF; 1215 #ifdef CONFIG_X86_32 1216 # ifdef CONFIG_SMP 1217 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0); 1218 # else 1219 c->apicid = c->initial_apicid; 1220 # endif 1221 #endif 1222 c->phys_proc_id = c->initial_apicid; 1223 } 1224 1225 get_model_name(c); /* Default name */ 1226 1227 detect_null_seg_behavior(c); 1228 1229 /* 1230 * ESPFIX is a strange bug. All real CPUs have it. Paravirt 1231 * systems that run Linux at CPL > 0 may or may not have the 1232 * issue, but, even if they have the issue, there's absolutely 1233 * nothing we can do about it because we can't use the real IRET 1234 * instruction. 1235 * 1236 * NB: For the time being, only 32-bit kernels support 1237 * X86_BUG_ESPFIX as such. 64-bit kernels directly choose 1238 * whether to apply espfix using paravirt hooks. If any 1239 * non-paravirt system ever shows up that does *not* have the 1240 * ESPFIX issue, we can change this. 1241 */ 1242 #ifdef CONFIG_X86_32 1243 # ifdef CONFIG_PARAVIRT 1244 do { 1245 extern void native_iret(void); 1246 if (pv_cpu_ops.iret == native_iret) 1247 set_cpu_bug(c, X86_BUG_ESPFIX); 1248 } while (0); 1249 # else 1250 set_cpu_bug(c, X86_BUG_ESPFIX); 1251 # endif 1252 #endif 1253 } 1254 1255 static void x86_init_cache_qos(struct cpuinfo_x86 *c) 1256 { 1257 /* 1258 * The heavy lifting of max_rmid and cache_occ_scale are handled 1259 * in get_cpu_cap(). Here we just set the max_rmid for the boot_cpu 1260 * in case CQM bits really aren't there in this CPU. 1261 */ 1262 if (c != &boot_cpu_data) { 1263 boot_cpu_data.x86_cache_max_rmid = 1264 min(boot_cpu_data.x86_cache_max_rmid, 1265 c->x86_cache_max_rmid); 1266 } 1267 } 1268 1269 /* 1270 * Validate that ACPI/mptables have the same information about the 1271 * effective APIC id and update the package map. 1272 */ 1273 static void validate_apic_and_package_id(struct cpuinfo_x86 *c) 1274 { 1275 #ifdef CONFIG_SMP 1276 unsigned int apicid, cpu = smp_processor_id(); 1277 1278 apicid = apic->cpu_present_to_apicid(cpu); 1279 1280 if (apicid != c->apicid) { 1281 pr_err(FW_BUG "CPU%u: APIC id mismatch. Firmware: %x APIC: %x\n", 1282 cpu, apicid, c->initial_apicid); 1283 } 1284 BUG_ON(topology_update_package_map(c->phys_proc_id, cpu)); 1285 #else 1286 c->logical_proc_id = 0; 1287 #endif 1288 } 1289 1290 /* 1291 * This does the hard work of actually picking apart the CPU stuff... 1292 */ 1293 static void identify_cpu(struct cpuinfo_x86 *c) 1294 { 1295 int i; 1296 1297 c->loops_per_jiffy = loops_per_jiffy; 1298 c->x86_cache_size = 0; 1299 c->x86_vendor = X86_VENDOR_UNKNOWN; 1300 c->x86_model = c->x86_stepping = 0; /* So far unknown... */ 1301 c->x86_vendor_id[0] = '\0'; /* Unset */ 1302 c->x86_model_id[0] = '\0'; /* Unset */ 1303 c->x86_max_cores = 1; 1304 c->x86_coreid_bits = 0; 1305 c->cu_id = 0xff; 1306 #ifdef CONFIG_X86_64 1307 c->x86_clflush_size = 64; 1308 c->x86_phys_bits = 36; 1309 c->x86_virt_bits = 48; 1310 #else 1311 c->cpuid_level = -1; /* CPUID not detected */ 1312 c->x86_clflush_size = 32; 1313 c->x86_phys_bits = 32; 1314 c->x86_virt_bits = 32; 1315 #endif 1316 c->x86_cache_alignment = c->x86_clflush_size; 1317 memset(&c->x86_capability, 0, sizeof c->x86_capability); 1318 1319 generic_identify(c); 1320 1321 if (this_cpu->c_identify) 1322 this_cpu->c_identify(c); 1323 1324 /* Clear/Set all flags overridden by options, after probe */ 1325 apply_forced_caps(c); 1326 1327 #ifdef CONFIG_X86_64 1328 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0); 1329 #endif 1330 1331 /* 1332 * Vendor-specific initialization. In this section we 1333 * canonicalize the feature flags, meaning if there are 1334 * features a certain CPU supports which CPUID doesn't 1335 * tell us, CPUID claiming incorrect flags, or other bugs, 1336 * we handle them here. 1337 * 1338 * At the end of this section, c->x86_capability better 1339 * indicate the features this CPU genuinely supports! 1340 */ 1341 if (this_cpu->c_init) 1342 this_cpu->c_init(c); 1343 1344 /* Disable the PN if appropriate */ 1345 squash_the_stupid_serial_number(c); 1346 1347 /* Set up SMEP/SMAP/UMIP */ 1348 setup_smep(c); 1349 setup_smap(c); 1350 setup_umip(c); 1351 1352 /* 1353 * The vendor-specific functions might have changed features. 1354 * Now we do "generic changes." 1355 */ 1356 1357 /* Filter out anything that depends on CPUID levels we don't have */ 1358 filter_cpuid_features(c, true); 1359 1360 /* If the model name is still unset, do table lookup. */ 1361 if (!c->x86_model_id[0]) { 1362 const char *p; 1363 p = table_lookup_model(c); 1364 if (p) 1365 strcpy(c->x86_model_id, p); 1366 else 1367 /* Last resort... */ 1368 sprintf(c->x86_model_id, "%02x/%02x", 1369 c->x86, c->x86_model); 1370 } 1371 1372 #ifdef CONFIG_X86_64 1373 detect_ht(c); 1374 #endif 1375 1376 x86_init_rdrand(c); 1377 x86_init_cache_qos(c); 1378 setup_pku(c); 1379 1380 /* 1381 * Clear/Set all flags overridden by options, need do it 1382 * before following smp all cpus cap AND. 1383 */ 1384 apply_forced_caps(c); 1385 1386 /* 1387 * On SMP, boot_cpu_data holds the common feature set between 1388 * all CPUs; so make sure that we indicate which features are 1389 * common between the CPUs. The first time this routine gets 1390 * executed, c == &boot_cpu_data. 1391 */ 1392 if (c != &boot_cpu_data) { 1393 /* AND the already accumulated flags with these */ 1394 for (i = 0; i < NCAPINTS; i++) 1395 boot_cpu_data.x86_capability[i] &= c->x86_capability[i]; 1396 1397 /* OR, i.e. replicate the bug flags */ 1398 for (i = NCAPINTS; i < NCAPINTS + NBUGINTS; i++) 1399 c->x86_capability[i] |= boot_cpu_data.x86_capability[i]; 1400 } 1401 1402 /* Init Machine Check Exception if available. */ 1403 mcheck_cpu_init(c); 1404 1405 select_idle_routine(c); 1406 1407 #ifdef CONFIG_NUMA 1408 numa_add_cpu(smp_processor_id()); 1409 #endif 1410 } 1411 1412 /* 1413 * Set up the CPU state needed to execute SYSENTER/SYSEXIT instructions 1414 * on 32-bit kernels: 1415 */ 1416 #ifdef CONFIG_X86_32 1417 void enable_sep_cpu(void) 1418 { 1419 struct tss_struct *tss; 1420 int cpu; 1421 1422 if (!boot_cpu_has(X86_FEATURE_SEP)) 1423 return; 1424 1425 cpu = get_cpu(); 1426 tss = &per_cpu(cpu_tss_rw, cpu); 1427 1428 /* 1429 * We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field -- 1430 * see the big comment in struct x86_hw_tss's definition. 1431 */ 1432 1433 tss->x86_tss.ss1 = __KERNEL_CS; 1434 wrmsr(MSR_IA32_SYSENTER_CS, tss->x86_tss.ss1, 0); 1435 wrmsr(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_entry_stack(cpu) + 1), 0); 1436 wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0); 1437 1438 put_cpu(); 1439 } 1440 #endif 1441 1442 void __init identify_boot_cpu(void) 1443 { 1444 identify_cpu(&boot_cpu_data); 1445 #ifdef CONFIG_X86_32 1446 sysenter_setup(); 1447 enable_sep_cpu(); 1448 #endif 1449 cpu_detect_tlb(&boot_cpu_data); 1450 } 1451 1452 void identify_secondary_cpu(struct cpuinfo_x86 *c) 1453 { 1454 BUG_ON(c == &boot_cpu_data); 1455 identify_cpu(c); 1456 #ifdef CONFIG_X86_32 1457 enable_sep_cpu(); 1458 #endif 1459 mtrr_ap_init(); 1460 validate_apic_and_package_id(c); 1461 x86_spec_ctrl_setup_ap(); 1462 } 1463 1464 static __init int setup_noclflush(char *arg) 1465 { 1466 setup_clear_cpu_cap(X86_FEATURE_CLFLUSH); 1467 setup_clear_cpu_cap(X86_FEATURE_CLFLUSHOPT); 1468 return 1; 1469 } 1470 __setup("noclflush", setup_noclflush); 1471 1472 void print_cpu_info(struct cpuinfo_x86 *c) 1473 { 1474 const char *vendor = NULL; 1475 1476 if (c->x86_vendor < X86_VENDOR_NUM) { 1477 vendor = this_cpu->c_vendor; 1478 } else { 1479 if (c->cpuid_level >= 0) 1480 vendor = c->x86_vendor_id; 1481 } 1482 1483 if (vendor && !strstr(c->x86_model_id, vendor)) 1484 pr_cont("%s ", vendor); 1485 1486 if (c->x86_model_id[0]) 1487 pr_cont("%s", c->x86_model_id); 1488 else 1489 pr_cont("%d86", c->x86); 1490 1491 pr_cont(" (family: 0x%x, model: 0x%x", c->x86, c->x86_model); 1492 1493 if (c->x86_stepping || c->cpuid_level >= 0) 1494 pr_cont(", stepping: 0x%x)\n", c->x86_stepping); 1495 else 1496 pr_cont(")\n"); 1497 } 1498 1499 /* 1500 * clearcpuid= was already parsed in fpu__init_parse_early_param. 1501 * But we need to keep a dummy __setup around otherwise it would 1502 * show up as an environment variable for init. 1503 */ 1504 static __init int setup_clearcpuid(char *arg) 1505 { 1506 return 1; 1507 } 1508 __setup("clearcpuid=", setup_clearcpuid); 1509 1510 #ifdef CONFIG_X86_64 1511 DEFINE_PER_CPU_FIRST(union irq_stack_union, 1512 irq_stack_union) __aligned(PAGE_SIZE) __visible; 1513 EXPORT_PER_CPU_SYMBOL_GPL(irq_stack_union); 1514 1515 /* 1516 * The following percpu variables are hot. Align current_task to 1517 * cacheline size such that they fall in the same cacheline. 1518 */ 1519 DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned = 1520 &init_task; 1521 EXPORT_PER_CPU_SYMBOL(current_task); 1522 1523 DEFINE_PER_CPU(char *, irq_stack_ptr) = 1524 init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE; 1525 1526 DEFINE_PER_CPU(unsigned int, irq_count) __visible = -1; 1527 1528 DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT; 1529 EXPORT_PER_CPU_SYMBOL(__preempt_count); 1530 1531 /* May not be marked __init: used by software suspend */ 1532 void syscall_init(void) 1533 { 1534 extern char _entry_trampoline[]; 1535 extern char entry_SYSCALL_64_trampoline[]; 1536 1537 int cpu = smp_processor_id(); 1538 unsigned long SYSCALL64_entry_trampoline = 1539 (unsigned long)get_cpu_entry_area(cpu)->entry_trampoline + 1540 (entry_SYSCALL_64_trampoline - _entry_trampoline); 1541 1542 wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS); 1543 if (static_cpu_has(X86_FEATURE_PTI)) 1544 wrmsrl(MSR_LSTAR, SYSCALL64_entry_trampoline); 1545 else 1546 wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64); 1547 1548 #ifdef CONFIG_IA32_EMULATION 1549 wrmsrl(MSR_CSTAR, (unsigned long)entry_SYSCALL_compat); 1550 /* 1551 * This only works on Intel CPUs. 1552 * On AMD CPUs these MSRs are 32-bit, CPU truncates MSR_IA32_SYSENTER_EIP. 1553 * This does not cause SYSENTER to jump to the wrong location, because 1554 * AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit). 1555 */ 1556 wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS); 1557 wrmsrl_safe(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_entry_stack(cpu) + 1)); 1558 wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat); 1559 #else 1560 wrmsrl(MSR_CSTAR, (unsigned long)ignore_sysret); 1561 wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG); 1562 wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL); 1563 wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL); 1564 #endif 1565 1566 /* Flags to clear on syscall */ 1567 wrmsrl(MSR_SYSCALL_MASK, 1568 X86_EFLAGS_TF|X86_EFLAGS_DF|X86_EFLAGS_IF| 1569 X86_EFLAGS_IOPL|X86_EFLAGS_AC|X86_EFLAGS_NT); 1570 } 1571 1572 /* 1573 * Copies of the original ist values from the tss are only accessed during 1574 * debugging, no special alignment required. 1575 */ 1576 DEFINE_PER_CPU(struct orig_ist, orig_ist); 1577 1578 static DEFINE_PER_CPU(unsigned long, debug_stack_addr); 1579 DEFINE_PER_CPU(int, debug_stack_usage); 1580 1581 int is_debug_stack(unsigned long addr) 1582 { 1583 return __this_cpu_read(debug_stack_usage) || 1584 (addr <= __this_cpu_read(debug_stack_addr) && 1585 addr > (__this_cpu_read(debug_stack_addr) - DEBUG_STKSZ)); 1586 } 1587 NOKPROBE_SYMBOL(is_debug_stack); 1588 1589 DEFINE_PER_CPU(u32, debug_idt_ctr); 1590 1591 void debug_stack_set_zero(void) 1592 { 1593 this_cpu_inc(debug_idt_ctr); 1594 load_current_idt(); 1595 } 1596 NOKPROBE_SYMBOL(debug_stack_set_zero); 1597 1598 void debug_stack_reset(void) 1599 { 1600 if (WARN_ON(!this_cpu_read(debug_idt_ctr))) 1601 return; 1602 if (this_cpu_dec_return(debug_idt_ctr) == 0) 1603 load_current_idt(); 1604 } 1605 NOKPROBE_SYMBOL(debug_stack_reset); 1606 1607 #else /* CONFIG_X86_64 */ 1608 1609 DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task; 1610 EXPORT_PER_CPU_SYMBOL(current_task); 1611 DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT; 1612 EXPORT_PER_CPU_SYMBOL(__preempt_count); 1613 1614 /* 1615 * On x86_32, vm86 modifies tss.sp0, so sp0 isn't a reliable way to find 1616 * the top of the kernel stack. Use an extra percpu variable to track the 1617 * top of the kernel stack directly. 1618 */ 1619 DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack) = 1620 (unsigned long)&init_thread_union + THREAD_SIZE; 1621 EXPORT_PER_CPU_SYMBOL(cpu_current_top_of_stack); 1622 1623 #ifdef CONFIG_STACKPROTECTOR 1624 DEFINE_PER_CPU_ALIGNED(struct stack_canary, stack_canary); 1625 #endif 1626 1627 #endif /* CONFIG_X86_64 */ 1628 1629 /* 1630 * Clear all 6 debug registers: 1631 */ 1632 static void clear_all_debug_regs(void) 1633 { 1634 int i; 1635 1636 for (i = 0; i < 8; i++) { 1637 /* Ignore db4, db5 */ 1638 if ((i == 4) || (i == 5)) 1639 continue; 1640 1641 set_debugreg(0, i); 1642 } 1643 } 1644 1645 #ifdef CONFIG_KGDB 1646 /* 1647 * Restore debug regs if using kgdbwait and you have a kernel debugger 1648 * connection established. 1649 */ 1650 static void dbg_restore_debug_regs(void) 1651 { 1652 if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break)) 1653 arch_kgdb_ops.correct_hw_break(); 1654 } 1655 #else /* ! CONFIG_KGDB */ 1656 #define dbg_restore_debug_regs() 1657 #endif /* ! CONFIG_KGDB */ 1658 1659 static void wait_for_master_cpu(int cpu) 1660 { 1661 #ifdef CONFIG_SMP 1662 /* 1663 * wait for ACK from master CPU before continuing 1664 * with AP initialization 1665 */ 1666 WARN_ON(cpumask_test_and_set_cpu(cpu, cpu_initialized_mask)); 1667 while (!cpumask_test_cpu(cpu, cpu_callout_mask)) 1668 cpu_relax(); 1669 #endif 1670 } 1671 1672 /* 1673 * cpu_init() initializes state that is per-CPU. Some data is already 1674 * initialized (naturally) in the bootstrap process, such as the GDT 1675 * and IDT. We reload them nevertheless, this function acts as a 1676 * 'CPU state barrier', nothing should get across. 1677 * A lot of state is already set up in PDA init for 64 bit 1678 */ 1679 #ifdef CONFIG_X86_64 1680 1681 void cpu_init(void) 1682 { 1683 struct orig_ist *oist; 1684 struct task_struct *me; 1685 struct tss_struct *t; 1686 unsigned long v; 1687 int cpu = raw_smp_processor_id(); 1688 int i; 1689 1690 wait_for_master_cpu(cpu); 1691 1692 /* 1693 * Initialize the CR4 shadow before doing anything that could 1694 * try to read it. 1695 */ 1696 cr4_init_shadow(); 1697 1698 if (cpu) 1699 load_ucode_ap(); 1700 1701 t = &per_cpu(cpu_tss_rw, cpu); 1702 oist = &per_cpu(orig_ist, cpu); 1703 1704 #ifdef CONFIG_NUMA 1705 if (this_cpu_read(numa_node) == 0 && 1706 early_cpu_to_node(cpu) != NUMA_NO_NODE) 1707 set_numa_node(early_cpu_to_node(cpu)); 1708 #endif 1709 1710 me = current; 1711 1712 pr_debug("Initializing CPU#%d\n", cpu); 1713 1714 cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE); 1715 1716 /* 1717 * Initialize the per-CPU GDT with the boot GDT, 1718 * and set up the GDT descriptor: 1719 */ 1720 1721 switch_to_new_gdt(cpu); 1722 loadsegment(fs, 0); 1723 1724 load_current_idt(); 1725 1726 memset(me->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8); 1727 syscall_init(); 1728 1729 wrmsrl(MSR_FS_BASE, 0); 1730 wrmsrl(MSR_KERNEL_GS_BASE, 0); 1731 barrier(); 1732 1733 x86_configure_nx(); 1734 x2apic_setup(); 1735 1736 /* 1737 * set up and load the per-CPU TSS 1738 */ 1739 if (!oist->ist[0]) { 1740 char *estacks = get_cpu_entry_area(cpu)->exception_stacks; 1741 1742 for (v = 0; v < N_EXCEPTION_STACKS; v++) { 1743 estacks += exception_stack_sizes[v]; 1744 oist->ist[v] = t->x86_tss.ist[v] = 1745 (unsigned long)estacks; 1746 if (v == DEBUG_STACK-1) 1747 per_cpu(debug_stack_addr, cpu) = (unsigned long)estacks; 1748 } 1749 } 1750 1751 t->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET; 1752 1753 /* 1754 * <= is required because the CPU will access up to 1755 * 8 bits beyond the end of the IO permission bitmap. 1756 */ 1757 for (i = 0; i <= IO_BITMAP_LONGS; i++) 1758 t->io_bitmap[i] = ~0UL; 1759 1760 mmgrab(&init_mm); 1761 me->active_mm = &init_mm; 1762 BUG_ON(me->mm); 1763 initialize_tlbstate_and_flush(); 1764 enter_lazy_tlb(&init_mm, me); 1765 1766 /* 1767 * Initialize the TSS. sp0 points to the entry trampoline stack 1768 * regardless of what task is running. 1769 */ 1770 set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); 1771 load_TR_desc(); 1772 load_sp0((unsigned long)(cpu_entry_stack(cpu) + 1)); 1773 1774 load_mm_ldt(&init_mm); 1775 1776 clear_all_debug_regs(); 1777 dbg_restore_debug_regs(); 1778 1779 fpu__init_cpu(); 1780 1781 if (is_uv_system()) 1782 uv_cpu_init(); 1783 1784 load_fixmap_gdt(cpu); 1785 } 1786 1787 #else 1788 1789 void cpu_init(void) 1790 { 1791 int cpu = smp_processor_id(); 1792 struct task_struct *curr = current; 1793 struct tss_struct *t = &per_cpu(cpu_tss_rw, cpu); 1794 1795 wait_for_master_cpu(cpu); 1796 1797 /* 1798 * Initialize the CR4 shadow before doing anything that could 1799 * try to read it. 1800 */ 1801 cr4_init_shadow(); 1802 1803 show_ucode_info_early(); 1804 1805 pr_info("Initializing CPU#%d\n", cpu); 1806 1807 if (cpu_feature_enabled(X86_FEATURE_VME) || 1808 boot_cpu_has(X86_FEATURE_TSC) || 1809 boot_cpu_has(X86_FEATURE_DE)) 1810 cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE); 1811 1812 load_current_idt(); 1813 switch_to_new_gdt(cpu); 1814 1815 /* 1816 * Set up and load the per-CPU TSS and LDT 1817 */ 1818 mmgrab(&init_mm); 1819 curr->active_mm = &init_mm; 1820 BUG_ON(curr->mm); 1821 initialize_tlbstate_and_flush(); 1822 enter_lazy_tlb(&init_mm, curr); 1823 1824 /* 1825 * Initialize the TSS. sp0 points to the entry trampoline stack 1826 * regardless of what task is running. 1827 */ 1828 set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); 1829 load_TR_desc(); 1830 load_sp0((unsigned long)(cpu_entry_stack(cpu) + 1)); 1831 1832 load_mm_ldt(&init_mm); 1833 1834 t->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET; 1835 1836 #ifdef CONFIG_DOUBLEFAULT 1837 /* Set up doublefault TSS pointer in the GDT */ 1838 __set_tss_desc(cpu, GDT_ENTRY_DOUBLEFAULT_TSS, &doublefault_tss); 1839 #endif 1840 1841 clear_all_debug_regs(); 1842 dbg_restore_debug_regs(); 1843 1844 fpu__init_cpu(); 1845 1846 load_fixmap_gdt(cpu); 1847 } 1848 #endif 1849 1850 static void bsp_resume(void) 1851 { 1852 if (this_cpu->c_bsp_resume) 1853 this_cpu->c_bsp_resume(&boot_cpu_data); 1854 } 1855 1856 static struct syscore_ops cpu_syscore_ops = { 1857 .resume = bsp_resume, 1858 }; 1859 1860 static int __init init_cpu_syscore(void) 1861 { 1862 register_syscore_ops(&cpu_syscore_ops); 1863 return 0; 1864 } 1865 core_initcall(init_cpu_syscore); 1866 1867 /* 1868 * The microcode loader calls this upon late microcode load to recheck features, 1869 * only when microcode has been updated. Caller holds microcode_mutex and CPU 1870 * hotplug lock. 1871 */ 1872 void microcode_check(void) 1873 { 1874 struct cpuinfo_x86 info; 1875 1876 perf_check_microcode(); 1877 1878 /* Reload CPUID max function as it might've changed. */ 1879 info.cpuid_level = cpuid_eax(0); 1880 1881 /* 1882 * Copy all capability leafs to pick up the synthetic ones so that 1883 * memcmp() below doesn't fail on that. The ones coming from CPUID will 1884 * get overwritten in get_cpu_cap(). 1885 */ 1886 memcpy(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability)); 1887 1888 get_cpu_cap(&info); 1889 1890 if (!memcmp(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability))) 1891 return; 1892 1893 pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n"); 1894 pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n"); 1895 } 1896