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

   1 /*
   2  * CPU Microcode Update Driver for Linux
   3  *
   4  * Copyright (C) 2000-2006 Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
   5  *            2006      Shaohua Li <shaohua.li@intel.com>
   6  *            2013-2016 Borislav Petkov <bp@alien8.de>
   7  *
   8  * X86 CPU microcode early update for Linux:
   9  *
  10  *      Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
  11  *                         H Peter Anvin" <hpa@zytor.com>
  12  *                (C) 2015 Borislav Petkov <bp@alien8.de>
  13  *
  14  * This driver allows to upgrade microcode on x86 processors.
  15  *
  16  * This program is free software; you can redistribute it and/or
  17  * modify it under the terms of the GNU General Public License
  18  * as published by the Free Software Foundation; either version
  19  * 2 of the License, or (at your option) any later version.
  20  */
  21
  22 #define pr_fmt(fmt) "microcode: " fmt
  23
  24 #include <linux/platform_device.h>
  25 #include <linux/syscore_ops.h>
  26 #include <linux/miscdevice.h>
  27 #include <linux/capability.h>
  28 #include <linux/firmware.h>
  29 #include <linux/kernel.h>
  30 #include <linux/mutex.h>
  31 #include <linux/cpu.h>
  32 #include <linux/fs.h>
  33 #include <linux/mm.h>
  34
  35 #include <asm/microcode_intel.h>
  36 #include <asm/cpu_device_id.h>
  37 #include <asm/microcode_amd.h>
  38 #include <asm/perf_event.h>
  39 #include <asm/microcode.h>
  40 #include <asm/processor.h>
  41 #include <asm/cmdline.h>
  42 #include <asm/setup.h>
  43
  44 #define DRIVER_VERSION  "2.2"
  45
  46 static struct microcode_ops     *microcode_ops;
  47 static bool dis_ucode_ldr = true;
  48
  49 LIST_HEAD(microcode_cache);
  50
  51 /*
  52  * Synchronization.
  53  *
  54  * All non cpu-hotplug-callback call sites use:
  55  *
  56  * - microcode_mutex to synchronize with each other;
  57  * - get/put_online_cpus() to synchronize with
  58  *   the cpu-hotplug-callback call sites.
  59  *
  60  * We guarantee that only a single cpu is being
  61  * updated at any particular moment of time.
  62  */
  63 static DEFINE_MUTEX(microcode_mutex);
  64
  65 struct ucode_cpu_info           ucode_cpu_info[NR_CPUS];
  66
  67 /*
  68  * Operations that are run on a target cpu:
  69  */
  70
  71 struct cpu_info_ctx {
  72         struct cpu_signature    *cpu_sig;
  73         int                     err;
  74 };
  75
  76 static bool __init check_loader_disabled_bsp(void)
  77 {
  78         static const char *__dis_opt_str = "dis_ucode_ldr";
  79         u32 a, b, c, d;
  80
  81 #ifdef CONFIG_X86_32
  82         const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
  83         const char *option  = (const char *)__pa_nodebug(__dis_opt_str);
  84         bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr);
  85
  86 #else /* CONFIG_X86_64 */
  87         const char *cmdline = boot_command_line;
  88         const char *option  = __dis_opt_str;
  89         bool *res = &dis_ucode_ldr;
  90 #endif
  91
  92         if (!have_cpuid_p())
  93                 return *res;
  94
  95         a = 1;
  96         c = 0;
  97         native_cpuid(&a, &b, &c, &d);
  98
  99         /*
 100          * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
 101          * completely accurate as xen pv guests don't see that CPUID bit set but
 102          * that's good enough as they don't land on the BSP path anyway.
 103          */
 104         if (c & BIT(31))
 105                 return *res;
 106
 107         if (cmdline_find_option_bool(cmdline, option) <= 0)
 108                 *res = false;
 109
 110         return *res;
 111 }
 112
 113 extern struct builtin_fw __start_builtin_fw[];
 114 extern struct builtin_fw __end_builtin_fw[];
 115
 116 bool get_builtin_firmware(struct cpio_data *cd, const char *name)
 117 {
 118 #ifdef CONFIG_FW_LOADER
 119         struct builtin_fw *b_fw;
 120
 121         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
 122                 if (!strcmp(name, b_fw->name)) {
 123                         cd->size = b_fw->size;
 124                         cd->data = b_fw->data;
 125                         return true;
 126                 }
 127         }
 128 #endif
 129         return false;
 130 }
 131
 132 void __init load_ucode_bsp(void)
 133 {
 134         int vendor;
 135         unsigned int family;
 136
 137         if (check_loader_disabled_bsp())
 138                 return;
 139
 140         vendor = x86_cpuid_vendor();
 141         family = x86_cpuid_family();
 142
 143         switch (vendor) {
 144         case X86_VENDOR_INTEL:
 145                 if (family >= 6)
 146                         load_ucode_intel_bsp();
 147                 break;
 148         case X86_VENDOR_AMD:
 149                 if (family >= 0x10)
 150                         load_ucode_amd_bsp(family);
 151                 break;
 152         default:
 153                 break;
 154         }
 155 }
 156
 157 static bool check_loader_disabled_ap(void)
 158 {
 159 #ifdef CONFIG_X86_32
 160         return *((bool *)__pa_nodebug(&dis_ucode_ldr));
 161 #else
 162         return dis_ucode_ldr;
 163 #endif
 164 }
 165
 166 void load_ucode_ap(void)
 167 {
 168         int vendor, family;
 169
 170         if (check_loader_disabled_ap())
 171                 return;
 172
 173         vendor = x86_cpuid_vendor();
 174         family = x86_cpuid_family();
 175
 176         switch (vendor) {
 177         case X86_VENDOR_INTEL:
 178                 if (family >= 6)
 179                         load_ucode_intel_ap();
 180                 break;
 181         case X86_VENDOR_AMD:
 182                 if (family >= 0x10)
 183                         load_ucode_amd_ap(family);
 184                 break;
 185         default:
 186                 break;
 187         }
 188 }
 189
 190 static int __init save_microcode_in_initrd(void)
 191 {
 192         struct cpuinfo_x86 *c = &boot_cpu_data;
 193
 194         switch (c->x86_vendor) {
 195         case X86_VENDOR_INTEL:
 196                 if (c->x86 >= 6)
 197                         return save_microcode_in_initrd_intel();
 198                 break;
 199         case X86_VENDOR_AMD:
 200                 if (c->x86 >= 0x10)
 201                         return save_microcode_in_initrd_amd(c->x86);
 202                 break;
 203         default:
 204                 break;
 205         }
 206
 207         return -EINVAL;
 208 }
 209
 210 struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
 211 {
 212 #ifdef CONFIG_BLK_DEV_INITRD
 213         unsigned long start = 0;
 214         size_t size;
 215
 216 #ifdef CONFIG_X86_32
 217         struct boot_params *params;
 218
 219         if (use_pa)
 220                 params = (struct boot_params *)__pa_nodebug(&boot_params);
 221         else
 222                 params = &boot_params;
 223
 224         size = params->hdr.ramdisk_size;
 225
 226         /*
 227          * Set start only if we have an initrd image. We cannot use initrd_start
 228          * because it is not set that early yet.
 229          */
 230         if (size)
 231                 start = params->hdr.ramdisk_image;
 232
 233 # else /* CONFIG_X86_64 */
 234         size  = (unsigned long)boot_params.ext_ramdisk_size << 32;
 235         size |= boot_params.hdr.ramdisk_size;
 236
 237         if (size) {
 238                 start  = (unsigned long)boot_params.ext_ramdisk_image << 32;
 239                 start |= boot_params.hdr.ramdisk_image;
 240
 241                 start += PAGE_OFFSET;
 242         }
 243 # endif
 244
 245         /*
 246          * Did we relocate the ramdisk?
 247          *
 248          * So we possibly relocate the ramdisk *after* applying microcode on the
 249          * BSP so we rely on use_pa (use physical addresses) - even if it is not
 250          * absolutely correct - to determine whether we've done the ramdisk
 251          * relocation already.
 252          */
 253         if (!use_pa && relocated_ramdisk)
 254                 start = initrd_start;
 255
 256         return find_cpio_data(path, (void *)start, size, NULL);
 257 #else /* !CONFIG_BLK_DEV_INITRD */
 258         return (struct cpio_data){ NULL, 0, "" };
 259 #endif
 260 }
 261
 262 void reload_early_microcode(void)
 263 {
 264         int vendor, family;
 265
 266         vendor = x86_cpuid_vendor();
 267         family = x86_cpuid_family();
 268
 269         switch (vendor) {
 270         case X86_VENDOR_INTEL:
 271                 if (family >= 6)
 272                         reload_ucode_intel();
 273                 break;
 274         case X86_VENDOR_AMD:
 275                 if (family >= 0x10)
 276                         reload_ucode_amd();
 277                 break;
 278         default:
 279                 break;
 280         }
 281 }
 282
 283 static void collect_cpu_info_local(void *arg)
 284 {
 285         struct cpu_info_ctx *ctx = arg;
 286
 287         ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
 288                                                    ctx->cpu_sig);
 289 }
 290
 291 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
 292 {
 293         struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
 294         int ret;
 295
 296         ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
 297         if (!ret)
 298                 ret = ctx.err;
 299
 300         return ret;
 301 }
 302
 303 static int collect_cpu_info(int cpu)
 304 {
 305         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 306         int ret;
 307
 308         memset(uci, 0, sizeof(*uci));
 309
 310         ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
 311         if (!ret)
 312                 uci->valid = 1;
 313
 314         return ret;
 315 }
 316
 317 struct apply_microcode_ctx {
 318         int err;
 319 };
 320
 321 static void apply_microcode_local(void *arg)
 322 {
 323         struct apply_microcode_ctx *ctx = arg;
 324
 325         ctx->err = microcode_ops->apply_microcode(smp_processor_id());
 326 }
 327
 328 static int apply_microcode_on_target(int cpu)
 329 {
 330         struct apply_microcode_ctx ctx = { .err = 0 };
 331         int ret;
 332
 333         ret = smp_call_function_single(cpu, apply_microcode_local, &ctx, 1);
 334         if (!ret)
 335                 ret = ctx.err;
 336
 337         return ret;
 338 }
 339
 340 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
 341 static int do_microcode_update(const void __user *buf, size_t size)
 342 {
 343         int error = 0;
 344         int cpu;
 345
 346         for_each_online_cpu(cpu) {
 347                 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 348                 enum ucode_state ustate;
 349
 350                 if (!uci->valid)
 351                         continue;
 352
 353                 ustate = microcode_ops->request_microcode_user(cpu, buf, size);
 354                 if (ustate == UCODE_ERROR) {
 355                         error = -1;
 356                         break;
 357                 } else if (ustate == UCODE_OK)
 358                         apply_microcode_on_target(cpu);
 359         }
 360
 361         return error;
 362 }
 363
 364 static int microcode_open(struct inode *inode, struct file *file)
 365 {
 366         return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
 367 }
 368
 369 static ssize_t microcode_write(struct file *file, const char __user *buf,
 370                                size_t len, loff_t *ppos)
 371 {
 372         ssize_t ret = -EINVAL;
 373
 374         if ((len >> PAGE_SHIFT) > totalram_pages) {
 375                 pr_err("too much data (max %ld pages)\n", totalram_pages);
 376                 return ret;
 377         }
 378
 379         get_online_cpus();
 380         mutex_lock(&microcode_mutex);
 381
 382         if (do_microcode_update(buf, len) == 0)
 383                 ret = (ssize_t)len;
 384
 385         if (ret > 0)
 386                 perf_check_microcode();
 387
 388         mutex_unlock(&microcode_mutex);
 389         put_online_cpus();
 390
 391         return ret;
 392 }
 393
 394 static const struct file_operations microcode_fops = {
 395         .owner                  = THIS_MODULE,
 396         .write                  = microcode_write,
 397         .open                   = microcode_open,
 398         .llseek         = no_llseek,
 399 };
 400
 401 static struct miscdevice microcode_dev = {
 402         .minor                  = MICROCODE_MINOR,
 403         .name                   = "microcode",
 404         .nodename               = "cpu/microcode",
 405         .fops                   = &microcode_fops,
 406 };
 407
 408 static int __init microcode_dev_init(void)
 409 {
 410         int error;
 411
 412         error = misc_register(&microcode_dev);
 413         if (error) {
 414                 pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
 415                 return error;
 416         }
 417
 418         return 0;
 419 }
 420
 421 static void __exit microcode_dev_exit(void)
 422 {
 423         misc_deregister(&microcode_dev);
 424 }
 425 #else
 426 #define microcode_dev_init()    0
 427 #define microcode_dev_exit()    do { } while (0)
 428 #endif
 429
 430 /* fake device for request_firmware */
 431 static struct platform_device   *microcode_pdev;
 432
 433 static int reload_for_cpu(int cpu)
 434 {
 435         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 436         enum ucode_state ustate;
 437         int err = 0;
 438
 439         if (!uci->valid)
 440                 return err;
 441
 442         ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, true);
 443         if (ustate == UCODE_OK)
 444                 apply_microcode_on_target(cpu);
 445         else
 446                 if (ustate == UCODE_ERROR)
 447                         err = -EINVAL;
 448         return err;
 449 }
 450
 451 static ssize_t reload_store(struct device *dev,
 452                             struct device_attribute *attr,
 453                             const char *buf, size_t size)
 454 {
 455         unsigned long val;
 456         int cpu;
 457         ssize_t ret = 0, tmp_ret;
 458
 459         ret = kstrtoul(buf, 0, &val);
 460         if (ret)
 461                 return ret;
 462
 463         if (val != 1)
 464                 return size;
 465
 466         get_online_cpus();
 467         mutex_lock(&microcode_mutex);
 468         for_each_online_cpu(cpu) {
 469                 tmp_ret = reload_for_cpu(cpu);
 470                 if (tmp_ret != 0)
 471                         pr_warn("Error reloading microcode on CPU %d\n", cpu);
 472
 473                 /* save retval of the first encountered reload error */
 474                 if (!ret)
 475                         ret = tmp_ret;
 476         }
 477         if (!ret)
 478                 perf_check_microcode();
 479         mutex_unlock(&microcode_mutex);
 480         put_online_cpus();
 481
 482         if (!ret)
 483                 ret = size;
 484
 485         return ret;
 486 }
 487
 488 static ssize_t version_show(struct device *dev,
 489                         struct device_attribute *attr, char *buf)
 490 {
 491         struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
 492
 493         return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
 494 }
 495
 496 static ssize_t pf_show(struct device *dev,
 497                         struct device_attribute *attr, char *buf)
 498 {
 499         struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
 500
 501         return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
 502 }
 503
 504 static DEVICE_ATTR(reload, 0200, NULL, reload_store);
 505 static DEVICE_ATTR(version, 0400, version_show, NULL);
 506 static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
 507
 508 static struct attribute *mc_default_attrs[] = {
 509         &dev_attr_version.attr,
 510         &dev_attr_processor_flags.attr,
 511         NULL
 512 };
 513
 514 static struct attribute_group mc_attr_group = {
 515         .attrs                  = mc_default_attrs,
 516         .name                   = "microcode",
 517 };
 518
 519 static void microcode_fini_cpu(int cpu)
 520 {
 521         if (microcode_ops->microcode_fini_cpu)
 522                 microcode_ops->microcode_fini_cpu(cpu);
 523 }
 524
 525 static enum ucode_state microcode_resume_cpu(int cpu)
 526 {
 527         if (apply_microcode_on_target(cpu))
 528                 return UCODE_ERROR;
 529
 530         pr_debug("CPU%d updated upon resume\n", cpu);
 531
 532         return UCODE_OK;
 533 }
 534
 535 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
 536 {
 537         enum ucode_state ustate;
 538         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 539
 540         if (uci->valid)
 541                 return UCODE_OK;
 542
 543         if (collect_cpu_info(cpu))
 544                 return UCODE_ERROR;
 545
 546         /* --dimm. Trigger a delayed update? */
 547         if (system_state != SYSTEM_RUNNING)
 548                 return UCODE_NFOUND;
 549
 550         ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev,
 551                                                      refresh_fw);
 552
 553         if (ustate == UCODE_OK) {
 554                 pr_debug("CPU%d updated upon init\n", cpu);
 555                 apply_microcode_on_target(cpu);
 556         }
 557
 558         return ustate;
 559 }
 560
 561 static enum ucode_state microcode_update_cpu(int cpu)
 562 {
 563         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 564
 565         /* Refresh CPU microcode revision after resume. */
 566         collect_cpu_info(cpu);
 567
 568         if (uci->valid)
 569                 return microcode_resume_cpu(cpu);
 570
 571         return microcode_init_cpu(cpu, false);
 572 }
 573
 574 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
 575 {
 576         int err, cpu = dev->id;
 577
 578         if (!cpu_online(cpu))
 579                 return 0;
 580
 581         pr_debug("CPU%d added\n", cpu);
 582
 583         err = sysfs_create_group(&dev->kobj, &mc_attr_group);
 584         if (err)
 585                 return err;
 586
 587         if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
 588                 return -EINVAL;
 589
 590         return err;
 591 }
 592
 593 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
 594 {
 595         int cpu = dev->id;
 596
 597         if (!cpu_online(cpu))
 598                 return;
 599
 600         pr_debug("CPU%d removed\n", cpu);
 601         microcode_fini_cpu(cpu);
 602         sysfs_remove_group(&dev->kobj, &mc_attr_group);
 603 }
 604
 605 static struct subsys_interface mc_cpu_interface = {
 606         .name                   = "microcode",
 607         .subsys                 = &cpu_subsys,
 608         .add_dev                = mc_device_add,
 609         .remove_dev             = mc_device_remove,
 610 };
 611
 612 /**
 613  * mc_bp_resume - Update boot CPU microcode during resume.
 614  */
 615 static void mc_bp_resume(void)
 616 {
 617         int cpu = smp_processor_id();
 618         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 619
 620         if (uci->valid && uci->mc)
 621                 microcode_ops->apply_microcode(cpu);
 622         else if (!uci->mc)
 623                 reload_early_microcode();
 624 }
 625
 626 static struct syscore_ops mc_syscore_ops = {
 627         .resume                 = mc_bp_resume,
 628 };
 629
 630 static int mc_cpu_online(unsigned int cpu)
 631 {
 632         struct device *dev;
 633
 634         dev = get_cpu_device(cpu);
 635         microcode_update_cpu(cpu);
 636         pr_debug("CPU%d added\n", cpu);
 637
 638         if (sysfs_create_group(&dev->kobj, &mc_attr_group))
 639                 pr_err("Failed to create group for CPU%d\n", cpu);
 640         return 0;
 641 }
 642
 643 static int mc_cpu_down_prep(unsigned int cpu)
 644 {
 645         struct device *dev;
 646
 647         dev = get_cpu_device(cpu);
 648         /* Suspend is in progress, only remove the interface */
 649         sysfs_remove_group(&dev->kobj, &mc_attr_group);
 650         pr_debug("CPU%d removed\n", cpu);
 651
 652         return 0;
 653 }
 654
 655 static struct attribute *cpu_root_microcode_attrs[] = {
 656         &dev_attr_reload.attr,
 657         NULL
 658 };
 659
 660 static struct attribute_group cpu_root_microcode_group = {
 661         .name  = "microcode",
 662         .attrs = cpu_root_microcode_attrs,
 663 };
 664
 665 int __init microcode_init(void)
 666 {
 667         struct cpuinfo_x86 *c = &boot_cpu_data;
 668         int error;
 669
 670         if (dis_ucode_ldr)
 671                 return -EINVAL;
 672
 673         if (c->x86_vendor == X86_VENDOR_INTEL)
 674                 microcode_ops = init_intel_microcode();
 675         else if (c->x86_vendor == X86_VENDOR_AMD)
 676                 microcode_ops = init_amd_microcode();
 677         else
 678                 pr_err("no support for this CPU vendor\n");
 679
 680         if (!microcode_ops)
 681                 return -ENODEV;
 682
 683         microcode_pdev = platform_device_register_simple("microcode", -1,
 684                                                          NULL, 0);
 685         if (IS_ERR(microcode_pdev))
 686                 return PTR_ERR(microcode_pdev);
 687
 688         get_online_cpus();
 689         mutex_lock(&microcode_mutex);
 690
 691         error = subsys_interface_register(&mc_cpu_interface);
 692         if (!error)
 693                 perf_check_microcode();
 694         mutex_unlock(&microcode_mutex);
 695         put_online_cpus();
 696
 697         if (error)
 698                 goto out_pdev;
 699
 700         error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
 701                                    &cpu_root_microcode_group);
 702
 703         if (error) {
 704                 pr_err("Error creating microcode group!\n");
 705                 goto out_driver;
 706         }
 707
 708         error = microcode_dev_init();
 709         if (error)
 710                 goto out_ucode_group;
 711
 712         register_syscore_ops(&mc_syscore_ops);
 713         cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
 714                                   mc_cpu_online, mc_cpu_down_prep);
 715
 716         pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
 717
 718         return 0;
 719
 720  out_ucode_group:
 721         sysfs_remove_group(&cpu_subsys.dev_root->kobj,
 722                            &cpu_root_microcode_group);
 723
 724  out_driver:
 725         get_online_cpus();
 726         mutex_lock(&microcode_mutex);
 727
 728         subsys_interface_unregister(&mc_cpu_interface);
 729
 730         mutex_unlock(&microcode_mutex);
 731         put_online_cpus();
 732
 733  out_pdev:
 734         platform_device_unregister(microcode_pdev);
 735         return error;
 736
 737 }
 738 fs_initcall(save_microcode_in_initrd);
 739 late_initcall(microcode_init);