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