arch/x86/kernel/cpu/microcode/core.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * CPU Microcode Update Driver for Linux
   4  *
   5  * Copyright (C) 2000-2006 Tigran Aivazian <aivazian.tigran@gmail.com>
   6  *            2006      Shaohua Li <shaohua.li@intel.com>
   7  *            2013-2016 Borislav Petkov <bp@alien8.de>
   8  *
   9  * X86 CPU microcode early update for Linux:
  10  *
  11  *      Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
  12  *                         H Peter Anvin" <hpa@zytor.com>
  13  *                (C) 2015 Borislav Petkov <bp@alien8.de>
  14  *
  15  * This driver allows to upgrade microcode on x86 processors.
  16  */
  17
  18 #define pr_fmt(fmt) "microcode: " fmt
  19
  20 #include <linux/platform_device.h>
  21 #include <linux/stop_machine.h>
  22 #include <linux/syscore_ops.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/capability.h>
  25 #include <linux/firmware.h>
  26 #include <linux/kernel.h>
  27 #include <linux/delay.h>
  28 #include <linux/mutex.h>
  29 #include <linux/cpu.h>
  30 #include <linux/nmi.h>
  31 #include <linux/fs.h>
  32 #include <linux/mm.h>
  33
  34 #include <asm/microcode_intel.h>
  35 #include <asm/cpu_device_id.h>
  36 #include <asm/microcode_amd.h>
  37 #include <asm/perf_event.h>
  38 #include <asm/microcode.h>
  39 #include <asm/processor.h>
  40 #include <asm/cmdline.h>
  41 #include <asm/setup.h>
  42
  43 #define DRIVER_VERSION  "2.2"
  44
  45 static struct microcode_ops     *microcode_ops;
  46 static bool dis_ucode_ldr = true;
  47
  48 bool initrd_gone;
  49
  50 LIST_HEAD(microcode_cache);
  51
  52 /*
  53  * Synchronization.
  54  *
  55  * All non cpu-hotplug-callback call sites use:
  56  *
  57  * - microcode_mutex to synchronize with each other;
  58  * - get/put_online_cpus() to synchronize with
  59  *   the cpu-hotplug-callback call sites.
  60  *
  61  * We guarantee that only a single cpu is being
  62  * updated at any particular moment of time.
  63  */
  64 static DEFINE_MUTEX(microcode_mutex);
  65
  66 struct ucode_cpu_info           ucode_cpu_info[NR_CPUS];
  67
  68 struct cpu_info_ctx {
  69         struct cpu_signature    *cpu_sig;
  70         int                     err;
  71 };
  72
  73 /*
  74  * Those patch levels cannot be updated to newer ones and thus should be final.
  75  */
  76 static u32 final_levels[] = {
  77         0x01000098,
  78         0x0100009f,
  79         0x010000af,
  80         0, /* T-101 terminator */
  81 };
  82
  83 /*
  84  * Check the current patch level on this CPU.
  85  *
  86  * Returns:
  87  *  - true: if update should stop
  88  *  - false: otherwise
  89  */
  90 static bool amd_check_current_patch_level(void)
  91 {
  92         u32 lvl, dummy, i;
  93         u32 *levels;
  94
  95         native_rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy);
  96
  97         if (IS_ENABLED(CONFIG_X86_32))
  98                 levels = (u32 *)__pa_nodebug(&final_levels);
  99         else
 100                 levels = final_levels;
 101
 102         for (i = 0; levels[i]; i++) {
 103                 if (lvl == levels[i])
 104                         return true;
 105         }
 106         return false;
 107 }
 108
 109 static bool __init check_loader_disabled_bsp(void)
 110 {
 111         static const char *__dis_opt_str = "dis_ucode_ldr";
 112
 113 #ifdef CONFIG_X86_32
 114         const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
 115         const char *option  = (const char *)__pa_nodebug(__dis_opt_str);
 116         bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr);
 117
 118 #else /* CONFIG_X86_64 */
 119         const char *cmdline = boot_command_line;
 120         const char *option  = __dis_opt_str;
 121         bool *res = &dis_ucode_ldr;
 122 #endif
 123
 124         /*
 125          * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
 126          * completely accurate as xen pv guests don't see that CPUID bit set but
 127          * that's good enough as they don't land on the BSP path anyway.
 128          */
 129         if (native_cpuid_ecx(1) & BIT(31))
 130                 return *res;
 131
 132         if (x86_cpuid_vendor() == X86_VENDOR_AMD) {
 133                 if (amd_check_current_patch_level())
 134                         return *res;
 135         }
 136
 137         if (cmdline_find_option_bool(cmdline, option) <= 0)
 138                 *res = false;
 139
 140         return *res;
 141 }
 142
 143 extern struct builtin_fw __start_builtin_fw[];
 144 extern struct builtin_fw __end_builtin_fw[];
 145
 146 bool get_builtin_firmware(struct cpio_data *cd, const char *name)
 147 {
 148 #ifdef CONFIG_FW_LOADER
 149         struct builtin_fw *b_fw;
 150
 151         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
 152                 if (!strcmp(name, b_fw->name)) {
 153                         cd->size = b_fw->size;
 154                         cd->data = b_fw->data;
 155                         return true;
 156                 }
 157         }
 158 #endif
 159         return false;
 160 }
 161
 162 void __init load_ucode_bsp(void)
 163 {
 164         unsigned int cpuid_1_eax;
 165         bool intel = true;
 166
 167         if (!have_cpuid_p())
 168                 return;
 169
 170         cpuid_1_eax = native_cpuid_eax(1);
 171
 172         switch (x86_cpuid_vendor()) {
 173         case X86_VENDOR_INTEL:
 174                 if (x86_family(cpuid_1_eax) < 6)
 175                         return;
 176                 break;
 177
 178         case X86_VENDOR_AMD:
 179                 if (x86_family(cpuid_1_eax) < 0x10)
 180                         return;
 181                 intel = false;
 182                 break;
 183
 184         default:
 185                 return;
 186         }
 187
 188         if (check_loader_disabled_bsp())
 189                 return;
 190
 191         if (intel)
 192                 load_ucode_intel_bsp();
 193         else
 194                 load_ucode_amd_bsp(cpuid_1_eax);
 195 }
 196
 197 static bool check_loader_disabled_ap(void)
 198 {
 199 #ifdef CONFIG_X86_32
 200         return *((bool *)__pa_nodebug(&dis_ucode_ldr));
 201 #else
 202         return dis_ucode_ldr;
 203 #endif
 204 }
 205
 206 void load_ucode_ap(void)
 207 {
 208         unsigned int cpuid_1_eax;
 209
 210         if (check_loader_disabled_ap())
 211                 return;
 212
 213         cpuid_1_eax = native_cpuid_eax(1);
 214
 215         switch (x86_cpuid_vendor()) {
 216         case X86_VENDOR_INTEL:
 217                 if (x86_family(cpuid_1_eax) >= 6)
 218                         load_ucode_intel_ap();
 219                 break;
 220         case X86_VENDOR_AMD:
 221                 if (x86_family(cpuid_1_eax) >= 0x10)
 222                         load_ucode_amd_ap(cpuid_1_eax);
 223                 break;
 224         default:
 225                 break;
 226         }
 227 }
 228
 229 static int __init save_microcode_in_initrd(void)
 230 {
 231         struct cpuinfo_x86 *c = &boot_cpu_data;
 232         int ret = -EINVAL;
 233
 234         switch (c->x86_vendor) {
 235         case X86_VENDOR_INTEL:
 236                 if (c->x86 >= 6)
 237                         ret = save_microcode_in_initrd_intel();
 238                 break;
 239         case X86_VENDOR_AMD:
 240                 if (c->x86 >= 0x10)
 241                         ret = save_microcode_in_initrd_amd(cpuid_eax(1));
 242                 break;
 243         default:
 244                 break;
 245         }
 246
 247         initrd_gone = true;
 248
 249         return ret;
 250 }
 251
 252 struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
 253 {
 254 #ifdef CONFIG_BLK_DEV_INITRD
 255         unsigned long start = 0;
 256         size_t size;
 257
 258 #ifdef CONFIG_X86_32
 259         struct boot_params *params;
 260
 261         if (use_pa)
 262                 params = (struct boot_params *)__pa_nodebug(&boot_params);
 263         else
 264                 params = &boot_params;
 265
 266         size = params->hdr.ramdisk_size;
 267
 268         /*
 269          * Set start only if we have an initrd image. We cannot use initrd_start
 270          * because it is not set that early yet.
 271          */
 272         if (size)
 273                 start = params->hdr.ramdisk_image;
 274
 275 # else /* CONFIG_X86_64 */
 276         size  = (unsigned long)boot_params.ext_ramdisk_size << 32;
 277         size |= boot_params.hdr.ramdisk_size;
 278
 279         if (size) {
 280                 start  = (unsigned long)boot_params.ext_ramdisk_image << 32;
 281                 start |= boot_params.hdr.ramdisk_image;
 282
 283                 start += PAGE_OFFSET;
 284         }
 285 # endif
 286
 287         /*
 288          * Fixup the start address: after reserve_initrd() runs, initrd_start
 289          * has the virtual address of the beginning of the initrd. It also
 290          * possibly relocates the ramdisk. In either case, initrd_start contains
 291          * the updated address so use that instead.
 292          *
 293          * initrd_gone is for the hotplug case where we've thrown out initrd
 294          * already.
 295          */
 296         if (!use_pa) {
 297                 if (initrd_gone)
 298                         return (struct cpio_data){ NULL, 0, "" };
 299                 if (initrd_start)
 300                         start = initrd_start;
 301         } else {
 302                 /*
 303                  * The picture with physical addresses is a bit different: we
 304                  * need to get the *physical* address to which the ramdisk was
 305                  * relocated, i.e., relocated_ramdisk (not initrd_start) and
 306                  * since we're running from physical addresses, we need to access
 307                  * relocated_ramdisk through its *physical* address too.
 308                  */
 309                 u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
 310                 if (*rr)
 311                         start = *rr;
 312         }
 313
 314         return find_cpio_data(path, (void *)start, size, NULL);
 315 #else /* !CONFIG_BLK_DEV_INITRD */
 316         return (struct cpio_data){ NULL, 0, "" };
 317 #endif
 318 }
 319
 320 void reload_early_microcode(void)
 321 {
 322         int vendor, family;
 323
 324         vendor = x86_cpuid_vendor();
 325         family = x86_cpuid_family();
 326
 327         switch (vendor) {
 328         case X86_VENDOR_INTEL:
 329                 if (family >= 6)
 330                         reload_ucode_intel();
 331                 break;
 332         case X86_VENDOR_AMD:
 333                 if (family >= 0x10)
 334                         reload_ucode_amd();
 335                 break;
 336         default:
 337                 break;
 338         }
 339 }
 340
 341 static void collect_cpu_info_local(void *arg)
 342 {
 343         struct cpu_info_ctx *ctx = arg;
 344
 345         ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
 346                                                    ctx->cpu_sig);
 347 }
 348
 349 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
 350 {
 351         struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
 352         int ret;
 353
 354         ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
 355         if (!ret)
 356                 ret = ctx.err;
 357
 358         return ret;
 359 }
 360
 361 static int collect_cpu_info(int cpu)
 362 {
 363         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 364         int ret;
 365
 366         memset(uci, 0, sizeof(*uci));
 367
 368         ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
 369         if (!ret)
 370                 uci->valid = 1;
 371
 372         return ret;
 373 }
 374
 375 static void apply_microcode_local(void *arg)
 376 {
 377         enum ucode_state *err = arg;
 378
 379         *err = microcode_ops->apply_microcode(smp_processor_id());
 380 }
 381
 382 static int apply_microcode_on_target(int cpu)
 383 {
 384         enum ucode_state err;
 385         int ret;
 386
 387         ret = smp_call_function_single(cpu, apply_microcode_local, &err, 1);
 388         if (!ret) {
 389                 if (err == UCODE_ERROR)
 390                         ret = 1;
 391         }
 392         return ret;
 393 }
 394
 395 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
 396 static int do_microcode_update(const void __user *buf, size_t size)
 397 {
 398         int error = 0;
 399         int cpu;
 400
 401         for_each_online_cpu(cpu) {
 402                 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 403                 enum ucode_state ustate;
 404
 405                 if (!uci->valid)
 406                         continue;
 407
 408                 ustate = microcode_ops->request_microcode_user(cpu, buf, size);
 409                 if (ustate == UCODE_ERROR) {
 410                         error = -1;
 411                         break;
 412                 } else if (ustate == UCODE_NEW) {
 413                         apply_microcode_on_target(cpu);
 414                 }
 415         }
 416
 417         return error;
 418 }
 419
 420 static int microcode_open(struct inode *inode, struct file *file)
 421 {
 422         return capable(CAP_SYS_RAWIO) ? stream_open(inode, file) : -EPERM;
 423 }
 424
 425 static ssize_t microcode_write(struct file *file, const char __user *buf,
 426                                size_t len, loff_t *ppos)
 427 {
 428         ssize_t ret = -EINVAL;
 429         unsigned long nr_pages = totalram_pages();
 430
 431         if ((len >> PAGE_SHIFT) > nr_pages) {
 432                 pr_err("too much data (max %ld pages)\n", nr_pages);
 433                 return ret;
 434         }
 435
 436         get_online_cpus();
 437         mutex_lock(&microcode_mutex);
 438
 439         if (do_microcode_update(buf, len) == 0)
 440                 ret = (ssize_t)len;
 441
 442         if (ret > 0)
 443                 perf_check_microcode();
 444
 445         mutex_unlock(&microcode_mutex);
 446         put_online_cpus();
 447
 448         return ret;
 449 }
 450
 451 static const struct file_operations microcode_fops = {
 452         .owner                  = THIS_MODULE,
 453         .write                  = microcode_write,
 454         .open                   = microcode_open,
 455         .llseek         = no_llseek,
 456 };
 457
 458 static struct miscdevice microcode_dev = {
 459         .minor                  = MICROCODE_MINOR,
 460         .name                   = "microcode",
 461         .nodename               = "cpu/microcode",
 462         .fops                   = &microcode_fops,
 463 };
 464
 465 static int __init microcode_dev_init(void)
 466 {
 467         int error;
 468
 469         error = misc_register(&microcode_dev);
 470         if (error) {
 471                 pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
 472                 return error;
 473         }
 474
 475         return 0;
 476 }
 477
 478 static void __exit microcode_dev_exit(void)
 479 {
 480         misc_deregister(&microcode_dev);
 481 }
 482 #else
 483 #define microcode_dev_init()    0
 484 #define microcode_dev_exit()    do { } while (0)
 485 #endif
 486
 487 /* fake device for request_firmware */
 488 static struct platform_device   *microcode_pdev;
 489
 490 /*
 491  * Late loading dance. Why the heavy-handed stomp_machine effort?
 492  *
 493  * - HT siblings must be idle and not execute other code while the other sibling
 494  *   is loading microcode in order to avoid any negative interactions caused by
 495  *   the loading.
 496  *
 497  * - In addition, microcode update on the cores must be serialized until this
 498  *   requirement can be relaxed in the future. Right now, this is conservative
 499  *   and good.
 500  */
 501 #define SPINUNIT 100 /* 100 nsec */
 502
 503 static int check_online_cpus(void)
 504 {
 505         unsigned int cpu;
 506
 507         /*
 508          * Make sure all CPUs are online.  It's fine for SMT to be disabled if
 509          * all the primary threads are still online.
 510          */
 511         for_each_present_cpu(cpu) {
 512                 if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) {
 513                         pr_err("Not all CPUs online, aborting microcode update.\n");
 514                         return -EINVAL;
 515                 }
 516         }
 517
 518         return 0;
 519 }
 520
 521 static atomic_t late_cpus_in;
 522 static atomic_t late_cpus_out;
 523
 524 static int __wait_for_cpus(atomic_t *t, long long timeout)
 525 {
 526         int all_cpus = num_online_cpus();
 527
 528         atomic_inc(t);
 529
 530         while (atomic_read(t) < all_cpus) {
 531                 if (timeout < SPINUNIT) {
 532                         pr_err("Timeout while waiting for CPUs rendezvous, remaining: %d\n",
 533                                 all_cpus - atomic_read(t));
 534                         return 1;
 535                 }
 536
 537                 ndelay(SPINUNIT);
 538                 timeout -= SPINUNIT;
 539
 540                 touch_nmi_watchdog();
 541         }
 542         return 0;
 543 }
 544
 545 /*
 546  * Returns:
 547  * < 0 - on error
 548  *   0 - no update done
 549  *   1 - microcode was updated
 550  */
 551 static int __reload_late(void *info)
 552 {
 553         int cpu = smp_processor_id();
 554         enum ucode_state err;
 555         int ret = 0;
 556
 557         /*
 558          * Wait for all CPUs to arrive. A load will not be attempted unless all
 559          * CPUs show up.
 560          * */
 561         if (__wait_for_cpus(&late_cpus_in, NSEC_PER_SEC))
 562                 return -1;
 563
 564         /*
 565          * On an SMT system, it suffices to load the microcode on one sibling of
 566          * the core because the microcode engine is shared between the threads.
 567          * Synchronization still needs to take place so that no concurrent
 568          * loading attempts happen on multiple threads of an SMT core. See
 569          * below.
 570          */
 571         if (cpumask_first(topology_sibling_cpumask(cpu)) == cpu)
 572                 apply_microcode_local(&err);
 573         else
 574                 goto wait_for_siblings;
 575
 576         if (err > UCODE_NFOUND) {
 577                 pr_warn("Error reloading microcode on CPU %d\n", cpu);
 578                 ret = -1;
 579         } else if (err == UCODE_UPDATED || err == UCODE_OK) {
 580                 ret = 1;
 581         }
 582
 583 wait_for_siblings:
 584         if (__wait_for_cpus(&late_cpus_out, NSEC_PER_SEC))
 585                 panic("Timeout during microcode update!\n");
 586
 587         /*
 588          * At least one thread has completed update on each core.
 589          * For others, simply call the update to make sure the
 590          * per-cpu cpuinfo can be updated with right microcode
 591          * revision.
 592          */
 593         if (cpumask_first(topology_sibling_cpumask(cpu)) != cpu)
 594                 apply_microcode_local(&err);
 595
 596         return ret;
 597 }
 598
 599 /*
 600  * Reload microcode late on all CPUs. Wait for a sec until they
 601  * all gather together.
 602  */
 603 static int microcode_reload_late(void)
 604 {
 605         int ret;
 606
 607         atomic_set(&late_cpus_in,  0);
 608         atomic_set(&late_cpus_out, 0);
 609
 610         ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
 611         if (ret > 0)
 612                 microcode_check();
 613
 614         pr_info("Reload completed, microcode revision: 0x%x\n", boot_cpu_data.microcode);
 615
 616         return ret;
 617 }
 618
 619 static ssize_t reload_store(struct device *dev,
 620                             struct device_attribute *attr,
 621                             const char *buf, size_t size)
 622 {
 623         enum ucode_state tmp_ret = UCODE_OK;
 624         int bsp = boot_cpu_data.cpu_index;
 625         unsigned long val;
 626         ssize_t ret = 0;
 627
 628         ret = kstrtoul(buf, 0, &val);
 629         if (ret)
 630                 return ret;
 631
 632         if (val != 1)
 633                 return size;
 634
 635         tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev, true);
 636         if (tmp_ret != UCODE_NEW)
 637                 return size;
 638
 639         get_online_cpus();
 640
 641         ret = check_online_cpus();
 642         if (ret)
 643                 goto put;
 644
 645         mutex_lock(&microcode_mutex);
 646         ret = microcode_reload_late();
 647         mutex_unlock(&microcode_mutex);
 648
 649 put:
 650         put_online_cpus();
 651
 652         if (ret >= 0)
 653                 ret = size;
 654
 655         return ret;
 656 }
 657
 658 static ssize_t version_show(struct device *dev,
 659                         struct device_attribute *attr, char *buf)
 660 {
 661         struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
 662
 663         return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
 664 }
 665
 666 static ssize_t pf_show(struct device *dev,
 667                         struct device_attribute *attr, char *buf)
 668 {
 669         struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
 670
 671         return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
 672 }
 673
 674 static DEVICE_ATTR_WO(reload);
 675 static DEVICE_ATTR(version, 0444, version_show, NULL);
 676 static DEVICE_ATTR(processor_flags, 0444, pf_show, NULL);
 677
 678 static struct attribute *mc_default_attrs[] = {
 679         &dev_attr_version.attr,
 680         &dev_attr_processor_flags.attr,
 681         NULL
 682 };
 683
 684 static const struct attribute_group mc_attr_group = {
 685         .attrs                  = mc_default_attrs,
 686         .name                   = "microcode",
 687 };
 688
 689 static void microcode_fini_cpu(int cpu)
 690 {
 691         if (microcode_ops->microcode_fini_cpu)
 692                 microcode_ops->microcode_fini_cpu(cpu);
 693 }
 694
 695 static enum ucode_state microcode_resume_cpu(int cpu)
 696 {
 697         if (apply_microcode_on_target(cpu))
 698                 return UCODE_ERROR;
 699
 700         pr_debug("CPU%d updated upon resume\n", cpu);
 701
 702         return UCODE_OK;
 703 }
 704
 705 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
 706 {
 707         enum ucode_state ustate;
 708         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 709
 710         if (uci->valid)
 711                 return UCODE_OK;
 712
 713         if (collect_cpu_info(cpu))
 714                 return UCODE_ERROR;
 715
 716         /* --dimm. Trigger a delayed update? */
 717         if (system_state != SYSTEM_RUNNING)
 718                 return UCODE_NFOUND;
 719
 720         ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, refresh_fw);
 721         if (ustate == UCODE_NEW) {
 722                 pr_debug("CPU%d updated upon init\n", cpu);
 723                 apply_microcode_on_target(cpu);
 724         }
 725
 726         return ustate;
 727 }
 728
 729 static enum ucode_state microcode_update_cpu(int cpu)
 730 {
 731         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 732
 733         /* Refresh CPU microcode revision after resume. */
 734         collect_cpu_info(cpu);
 735
 736         if (uci->valid)
 737                 return microcode_resume_cpu(cpu);
 738
 739         return microcode_init_cpu(cpu, false);
 740 }
 741
 742 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
 743 {
 744         int err, cpu = dev->id;
 745
 746         if (!cpu_online(cpu))
 747                 return 0;
 748
 749         pr_debug("CPU%d added\n", cpu);
 750
 751         err = sysfs_create_group(&dev->kobj, &mc_attr_group);
 752         if (err)
 753                 return err;
 754
 755         if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
 756                 return -EINVAL;
 757
 758         return err;
 759 }
 760
 761 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
 762 {
 763         int cpu = dev->id;
 764
 765         if (!cpu_online(cpu))
 766                 return;
 767
 768         pr_debug("CPU%d removed\n", cpu);
 769         microcode_fini_cpu(cpu);
 770         sysfs_remove_group(&dev->kobj, &mc_attr_group);
 771 }
 772
 773 static struct subsys_interface mc_cpu_interface = {
 774         .name                   = "microcode",
 775         .subsys                 = &cpu_subsys,
 776         .add_dev                = mc_device_add,
 777         .remove_dev             = mc_device_remove,
 778 };
 779
 780 /**
 781  * mc_bp_resume - Update boot CPU microcode during resume.
 782  */
 783 static void mc_bp_resume(void)
 784 {
 785         int cpu = smp_processor_id();
 786         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 787
 788         if (uci->valid && uci->mc)
 789                 microcode_ops->apply_microcode(cpu);
 790         else if (!uci->mc)
 791                 reload_early_microcode();
 792 }
 793
 794 static struct syscore_ops mc_syscore_ops = {
 795         .resume                 = mc_bp_resume,
 796 };
 797
 798 static int mc_cpu_starting(unsigned int cpu)
 799 {
 800         microcode_update_cpu(cpu);
 801         pr_debug("CPU%d added\n", cpu);
 802         return 0;
 803 }
 804
 805 static int mc_cpu_online(unsigned int cpu)
 806 {
 807         struct device *dev = get_cpu_device(cpu);
 808
 809         if (sysfs_create_group(&dev->kobj, &mc_attr_group))
 810                 pr_err("Failed to create group for CPU%d\n", cpu);
 811         return 0;
 812 }
 813
 814 static int mc_cpu_down_prep(unsigned int cpu)
 815 {
 816         struct device *dev;
 817
 818         dev = get_cpu_device(cpu);
 819         /* Suspend is in progress, only remove the interface */
 820         sysfs_remove_group(&dev->kobj, &mc_attr_group);
 821         pr_debug("CPU%d removed\n", cpu);
 822
 823         return 0;
 824 }
 825
 826 static struct attribute *cpu_root_microcode_attrs[] = {
 827         &dev_attr_reload.attr,
 828         NULL
 829 };
 830
 831 static const struct attribute_group cpu_root_microcode_group = {
 832         .name  = "microcode",
 833         .attrs = cpu_root_microcode_attrs,
 834 };
 835
 836 int __init microcode_init(void)
 837 {
 838         struct cpuinfo_x86 *c = &boot_cpu_data;
 839         int error;
 840
 841         if (dis_ucode_ldr)
 842                 return -EINVAL;
 843
 844         if (c->x86_vendor == X86_VENDOR_INTEL)
 845                 microcode_ops = init_intel_microcode();
 846         else if (c->x86_vendor == X86_VENDOR_AMD)
 847                 microcode_ops = init_amd_microcode();
 848         else
 849                 pr_err("no support for this CPU vendor\n");
 850
 851         if (!microcode_ops)
 852                 return -ENODEV;
 853
 854         microcode_pdev = platform_device_register_simple("microcode", -1,
 855                                                          NULL, 0);
 856         if (IS_ERR(microcode_pdev))
 857                 return PTR_ERR(microcode_pdev);
 858
 859         get_online_cpus();
 860         mutex_lock(&microcode_mutex);
 861
 862         error = subsys_interface_register(&mc_cpu_interface);
 863         if (!error)
 864                 perf_check_microcode();
 865         mutex_unlock(&microcode_mutex);
 866         put_online_cpus();
 867
 868         if (error)
 869                 goto out_pdev;
 870
 871         error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
 872                                    &cpu_root_microcode_group);
 873
 874         if (error) {
 875                 pr_err("Error creating microcode group!\n");
 876                 goto out_driver;
 877         }
 878
 879         error = microcode_dev_init();
 880         if (error)
 881                 goto out_ucode_group;
 882
 883         register_syscore_ops(&mc_syscore_ops);
 884         cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
 885                                   mc_cpu_starting, NULL);
 886         cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
 887                                   mc_cpu_online, mc_cpu_down_prep);
 888
 889         pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
 890
 891         return 0;
 892
 893  out_ucode_group:
 894         sysfs_remove_group(&cpu_subsys.dev_root->kobj,
 895                            &cpu_root_microcode_group);
 896
 897  out_driver:
 898         get_online_cpus();
 899         mutex_lock(&microcode_mutex);
 900
 901         subsys_interface_unregister(&mc_cpu_interface);
 902
 903         mutex_unlock(&microcode_mutex);
 904         put_online_cpus();
 905
 906  out_pdev:
 907         platform_device_unregister(microcode_pdev);
 908         return error;
 909
 910 }
 911 fs_initcall(save_microcode_in_initrd);
 912 late_initcall(microcode_init);