arch/x86/cpu/mp_init.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2015 Google, Inc
   4  *
   5  * Based on code from the coreboot file of the same name
   6  */
   7
   8 #include <common.h>
   9 #include <cpu.h>
  10 #include <dm.h>
  11 #include <errno.h>
  12 #include <malloc.h>
  13 #include <qfw.h>
  14 #include <asm/atomic.h>
  15 #include <asm/cpu.h>
  16 #include <asm/interrupt.h>
  17 #include <asm/lapic.h>
  18 #include <asm/microcode.h>
  19 #include <asm/mp.h>
  20 #include <asm/msr.h>
  21 #include <asm/mtrr.h>
  22 #include <asm/processor.h>
  23 #include <asm/sipi.h>
  24 #include <dm/device-internal.h>
  25 #include <dm/uclass-internal.h>
  26 #include <dm/lists.h>
  27 #include <dm/root.h>
  28 #include <linux/linkage.h>
  29
  30 DECLARE_GLOBAL_DATA_PTR;
  31
  32 /* Total CPUs include BSP */
  33 static int num_cpus;
  34
  35 /* This also needs to match the sipi.S assembly code for saved MSR encoding */
  36 struct saved_msr {
  37         uint32_t index;
  38         uint32_t lo;
  39         uint32_t hi;
  40 } __packed;
  41
  42
  43 struct mp_flight_plan {
  44         int num_records;
  45         struct mp_flight_record *records;
  46 };
  47
  48 static struct mp_flight_plan mp_info;
  49
  50 struct cpu_map {
  51         struct udevice *dev;
  52         int apic_id;
  53         int err_code;
  54 };
  55
  56 static inline void barrier_wait(atomic_t *b)
  57 {
  58         while (atomic_read(b) == 0)
  59                 asm("pause");
  60         mfence();
  61 }
  62
  63 static inline void release_barrier(atomic_t *b)
  64 {
  65         mfence();
  66         atomic_set(b, 1);
  67 }
  68
  69 static inline void stop_this_cpu(void)
  70 {
  71         /* Called by an AP when it is ready to halt and wait for a new task */
  72         for (;;)
  73                 cpu_hlt();
  74 }
  75
  76 /* Returns 1 if timeout waiting for APs. 0 if target APs found */
  77 static int wait_for_aps(atomic_t *val, int target, int total_delay,
  78                         int delay_step)
  79 {
  80         int timeout = 0;
  81         int delayed = 0;
  82
  83         while (atomic_read(val) != target) {
  84                 udelay(delay_step);
  85                 delayed += delay_step;
  86                 if (delayed >= total_delay) {
  87                         timeout = 1;
  88                         break;
  89                 }
  90         }
  91
  92         return timeout;
  93 }
  94
  95 static void ap_do_flight_plan(struct udevice *cpu)
  96 {
  97         int i;
  98
  99         for (i = 0; i < mp_info.num_records; i++) {
 100                 struct mp_flight_record *rec = &mp_info.records[i];
 101
 102                 atomic_inc(&rec->cpus_entered);
 103                 barrier_wait(&rec->barrier);
 104
 105                 if (rec->ap_call != NULL)
 106                         rec->ap_call(cpu, rec->ap_arg);
 107         }
 108 }
 109
 110 static int find_cpu_by_apic_id(int apic_id, struct udevice **devp)
 111 {
 112         struct udevice *dev;
 113
 114         *devp = NULL;
 115         for (uclass_find_first_device(UCLASS_CPU, &dev);
 116              dev;
 117              uclass_find_next_device(&dev)) {
 118                 struct cpu_platdata *plat = dev_get_parent_platdata(dev);
 119
 120                 if (plat->cpu_id == apic_id) {
 121                         *devp = dev;
 122                         return 0;
 123                 }
 124         }
 125
 126         return -ENOENT;
 127 }
 128
 129 /*
 130  * By the time APs call ap_init() caching has been setup, and microcode has
 131  * been loaded
 132  */
 133 static void ap_init(unsigned int cpu_index)
 134 {
 135         struct udevice *dev;
 136         int apic_id;
 137         int ret;
 138
 139         /* Ensure the local apic is enabled */
 140         enable_lapic();
 141
 142         apic_id = lapicid();
 143         ret = find_cpu_by_apic_id(apic_id, &dev);
 144         if (ret) {
 145                 debug("Unknown CPU apic_id %x\n", apic_id);
 146                 goto done;
 147         }
 148
 149         debug("AP: slot %d apic_id %x, dev %s\n", cpu_index, apic_id,
 150               dev ? dev->name : "(apic_id not found)");
 151
 152         /* Walk the flight plan */
 153         ap_do_flight_plan(dev);
 154
 155         /* Park the AP */
 156         debug("parking\n");
 157 done:
 158         stop_this_cpu();
 159 }
 160
 161 static const unsigned int fixed_mtrrs[NUM_FIXED_MTRRS] = {
 162         MTRR_FIX_64K_00000_MSR, MTRR_FIX_16K_80000_MSR, MTRR_FIX_16K_A0000_MSR,
 163         MTRR_FIX_4K_C0000_MSR, MTRR_FIX_4K_C8000_MSR, MTRR_FIX_4K_D0000_MSR,
 164         MTRR_FIX_4K_D8000_MSR, MTRR_FIX_4K_E0000_MSR, MTRR_FIX_4K_E8000_MSR,
 165         MTRR_FIX_4K_F0000_MSR, MTRR_FIX_4K_F8000_MSR,
 166 };
 167
 168 static inline struct saved_msr *save_msr(int index, struct saved_msr *entry)
 169 {
 170         msr_t msr;
 171
 172         msr = msr_read(index);
 173         entry->index = index;
 174         entry->lo = msr.lo;
 175         entry->hi = msr.hi;
 176
 177         /* Return the next entry */
 178         entry++;
 179         return entry;
 180 }
 181
 182 static int save_bsp_msrs(char *start, int size)
 183 {
 184         int msr_count;
 185         int num_var_mtrrs;
 186         struct saved_msr *msr_entry;
 187         int i;
 188         msr_t msr;
 189
 190         /* Determine number of MTRRs need to be saved */
 191         msr = msr_read(MTRR_CAP_MSR);
 192         num_var_mtrrs = msr.lo & 0xff;
 193
 194         /* 2 * num_var_mtrrs for base and mask. +1 for IA32_MTRR_DEF_TYPE */
 195         msr_count = 2 * num_var_mtrrs + NUM_FIXED_MTRRS + 1;
 196
 197         if ((msr_count * sizeof(struct saved_msr)) > size) {
 198                 printf("Cannot mirror all %d msrs\n", msr_count);
 199                 return -ENOSPC;
 200         }
 201
 202         msr_entry = (void *)start;
 203         for (i = 0; i < NUM_FIXED_MTRRS; i++)
 204                 msr_entry = save_msr(fixed_mtrrs[i], msr_entry);
 205
 206         for (i = 0; i < num_var_mtrrs; i++) {
 207                 msr_entry = save_msr(MTRR_PHYS_BASE_MSR(i), msr_entry);
 208                 msr_entry = save_msr(MTRR_PHYS_MASK_MSR(i), msr_entry);
 209         }
 210
 211         msr_entry = save_msr(MTRR_DEF_TYPE_MSR, msr_entry);
 212
 213         return msr_count;
 214 }
 215
 216 static int load_sipi_vector(atomic_t **ap_countp, int num_cpus)
 217 {
 218         struct sipi_params_16bit *params16;
 219         struct sipi_params *params;
 220         static char msr_save[512];
 221         char *stack;
 222         ulong addr;
 223         int code_len;
 224         int size;
 225         int ret;
 226
 227         /* Copy in the code */
 228         code_len = ap_start16_code_end - ap_start16;
 229         debug("Copying SIPI code to %x: %d bytes\n", AP_DEFAULT_BASE,
 230               code_len);
 231         memcpy((void *)AP_DEFAULT_BASE, ap_start16, code_len);
 232
 233         addr = AP_DEFAULT_BASE + (ulong)sipi_params_16bit - (ulong)ap_start16;
 234         params16 = (struct sipi_params_16bit *)addr;
 235         params16->ap_start = (uint32_t)ap_start;
 236         params16->gdt = (uint32_t)gd->arch.gdt;
 237         params16->gdt_limit = X86_GDT_SIZE - 1;
 238         debug("gdt = %x, gdt_limit = %x\n", params16->gdt, params16->gdt_limit);
 239
 240         params = (struct sipi_params *)sipi_params;
 241         debug("SIPI 32-bit params at %p\n", params);
 242         params->idt_ptr = (uint32_t)x86_get_idt();
 243
 244         params->stack_size = CONFIG_AP_STACK_SIZE;
 245         size = params->stack_size * num_cpus;
 246         stack = memalign(4096, size);
 247         if (!stack)
 248                 return -ENOMEM;
 249         params->stack_top = (u32)(stack + size);
 250 #if !defined(CONFIG_QEMU) && !defined(CONFIG_HAVE_FSP) && \
 251         !defined(CONFIG_INTEL_MID)
 252         params->microcode_ptr = ucode_base;
 253         debug("Microcode at %x\n", params->microcode_ptr);
 254 #endif
 255         params->msr_table_ptr = (u32)msr_save;
 256         ret = save_bsp_msrs(msr_save, sizeof(msr_save));
 257         if (ret < 0)
 258                 return ret;
 259         params->msr_count = ret;
 260
 261         params->c_handler = (uint32_t)&ap_init;
 262
 263         *ap_countp = &params->ap_count;
 264         atomic_set(*ap_countp, 0);
 265         debug("SIPI vector is ready\n");
 266
 267         return 0;
 268 }
 269
 270 static int check_cpu_devices(int expected_cpus)
 271 {
 272         int i;
 273
 274         for (i = 0; i < expected_cpus; i++) {
 275                 struct udevice *dev;
 276                 int ret;
 277
 278                 ret = uclass_find_device(UCLASS_CPU, i, &dev);
 279                 if (ret) {
 280                         debug("Cannot find CPU %d in device tree\n", i);
 281                         return ret;
 282                 }
 283         }
 284
 285         return 0;
 286 }
 287
 288 /* Returns 1 for timeout. 0 on success */
 289 static int apic_wait_timeout(int total_delay, const char *msg)
 290 {
 291         int total = 0;
 292
 293         if (!(lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY))
 294                 return 0;
 295
 296         debug("Waiting for %s...", msg);
 297         while (lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY) {
 298                 udelay(50);
 299                 total += 50;
 300                 if (total >= total_delay) {
 301                         debug("timed out: aborting\n");
 302                         return -ETIMEDOUT;
 303                 }
 304         }
 305         debug("done\n");
 306
 307         return 0;
 308 }
 309
 310 static int start_aps(int ap_count, atomic_t *num_aps)
 311 {
 312         int sipi_vector;
 313         /* Max location is 4KiB below 1MiB */
 314         const int max_vector_loc = ((1 << 20) - (1 << 12)) >> 12;
 315
 316         if (ap_count == 0)
 317                 return 0;
 318
 319         /* The vector is sent as a 4k aligned address in one byte */
 320         sipi_vector = AP_DEFAULT_BASE >> 12;
 321
 322         if (sipi_vector > max_vector_loc) {
 323                 printf("SIPI vector too large! 0x%08x\n",
 324                        sipi_vector);
 325                 return -1;
 326         }
 327
 328         debug("Attempting to start %d APs\n", ap_count);
 329
 330         if (apic_wait_timeout(1000, "ICR not to be busy"))
 331                 return -ETIMEDOUT;
 332
 333         /* Send INIT IPI to all but self */
 334         lapic_write(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(0));
 335         lapic_write(LAPIC_ICR, LAPIC_DEST_ALLBUT | LAPIC_INT_ASSERT |
 336                     LAPIC_DM_INIT);
 337         debug("Waiting for 10ms after sending INIT\n");
 338         mdelay(10);
 339
 340         /* Send 1st SIPI */
 341         if (apic_wait_timeout(1000, "ICR not to be busy"))
 342                 return -ETIMEDOUT;
 343
 344         lapic_write(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(0));
 345         lapic_write(LAPIC_ICR, LAPIC_DEST_ALLBUT | LAPIC_INT_ASSERT |
 346                     LAPIC_DM_STARTUP | sipi_vector);
 347         if (apic_wait_timeout(10000, "first SIPI to complete"))
 348                 return -ETIMEDOUT;
 349
 350         /* Wait for CPUs to check in up to 200 us */
 351         wait_for_aps(num_aps, ap_count, 200, 15);
 352
 353         /* Send 2nd SIPI */
 354         if (apic_wait_timeout(1000, "ICR not to be busy"))
 355                 return -ETIMEDOUT;
 356
 357         lapic_write(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(0));
 358         lapic_write(LAPIC_ICR, LAPIC_DEST_ALLBUT | LAPIC_INT_ASSERT |
 359                     LAPIC_DM_STARTUP | sipi_vector);
 360         if (apic_wait_timeout(10000, "second SIPI to complete"))
 361                 return -ETIMEDOUT;
 362
 363         /* Wait for CPUs to check in */
 364         if (wait_for_aps(num_aps, ap_count, 10000, 50)) {
 365                 debug("Not all APs checked in: %d/%d\n",
 366                       atomic_read(num_aps), ap_count);
 367                 return -1;
 368         }
 369
 370         return 0;
 371 }
 372
 373 static int bsp_do_flight_plan(struct udevice *cpu, struct mp_params *mp_params)
 374 {
 375         int i;
 376         int ret = 0;
 377         const int timeout_us = 100000;
 378         const int step_us = 100;
 379         int num_aps = num_cpus - 1;
 380
 381         for (i = 0; i < mp_params->num_records; i++) {
 382                 struct mp_flight_record *rec = &mp_params->flight_plan[i];
 383
 384                 /* Wait for APs if the record is not released */
 385                 if (atomic_read(&rec->barrier) == 0) {
 386                         /* Wait for the APs to check in */
 387                         if (wait_for_aps(&rec->cpus_entered, num_aps,
 388                                          timeout_us, step_us)) {
 389                                 debug("MP record %d timeout\n", i);
 390                                 ret = -1;
 391                         }
 392                 }
 393
 394                 if (rec->bsp_call != NULL)
 395                         rec->bsp_call(cpu, rec->bsp_arg);
 396
 397                 release_barrier(&rec->barrier);
 398         }
 399         return ret;
 400 }
 401
 402 static int init_bsp(struct udevice **devp)
 403 {
 404         char processor_name[CPU_MAX_NAME_LEN];
 405         int apic_id;
 406         int ret;
 407
 408         cpu_get_name(processor_name);
 409         debug("CPU: %s\n", processor_name);
 410
 411         apic_id = lapicid();
 412         ret = find_cpu_by_apic_id(apic_id, devp);
 413         if (ret) {
 414                 printf("Cannot find boot CPU, APIC ID %d\n", apic_id);
 415                 return ret;
 416         }
 417
 418         return 0;
 419 }
 420
 421 #ifdef CONFIG_QFW
 422 static int qemu_cpu_fixup(void)
 423 {
 424         int ret;
 425         int cpu_num;
 426         int cpu_online;
 427         struct udevice *dev, *pdev;
 428         struct cpu_platdata *plat;
 429         char *cpu;
 430
 431         /* first we need to find '/cpus' */
 432         for (device_find_first_child(dm_root(), &pdev);
 433              pdev;
 434              device_find_next_child(&pdev)) {
 435                 if (!strcmp(pdev->name, "cpus"))
 436                         break;
 437         }
 438         if (!pdev) {
 439                 printf("unable to find cpus device\n");
 440                 return -ENODEV;
 441         }
 442
 443         /* calculate cpus that are already bound */
 444         cpu_num = 0;
 445         for (uclass_find_first_device(UCLASS_CPU, &dev);
 446              dev;
 447              uclass_find_next_device(&dev)) {
 448                 cpu_num++;
 449         }
 450
 451         /* get actual cpu number */
 452         cpu_online = qemu_fwcfg_online_cpus();
 453         if (cpu_online < 0) {
 454                 printf("unable to get online cpu number: %d\n", cpu_online);
 455                 return cpu_online;
 456         }
 457
 458         /* bind addtional cpus */
 459         dev = NULL;
 460         for (; cpu_num < cpu_online; cpu_num++) {
 461                 /*
 462                  * allocate device name here as device_bind_driver() does
 463                  * not copy device name, 8 bytes are enough for
 464                  * sizeof("cpu@") + 3 digits cpu number + '\0'
 465                  */
 466                 cpu = malloc(8);
 467                 if (!cpu) {
 468                         printf("unable to allocate device name\n");
 469                         return -ENOMEM;
 470                 }
 471                 sprintf(cpu, "cpu@%d", cpu_num);
 472                 ret = device_bind_driver(pdev, "cpu_qemu", cpu, &dev);
 473                 if (ret) {
 474                         printf("binding cpu@%d failed: %d\n", cpu_num, ret);
 475                         return ret;
 476                 }
 477                 plat = dev_get_parent_platdata(dev);
 478                 plat->cpu_id = cpu_num;
 479         }
 480         return 0;
 481 }
 482 #endif
 483
 484 int mp_init(struct mp_params *p)
 485 {
 486         int num_aps;
 487         atomic_t *ap_count;
 488         struct udevice *cpu;
 489         int ret;
 490
 491         /* This will cause the CPUs devices to be bound */
 492         struct uclass *uc;
 493         ret = uclass_get(UCLASS_CPU, &uc);
 494         if (ret)
 495                 return ret;
 496
 497 #ifdef CONFIG_QFW
 498         ret = qemu_cpu_fixup();
 499         if (ret)
 500                 return ret;
 501 #endif
 502
 503         ret = init_bsp(&cpu);
 504         if (ret) {
 505                 debug("Cannot init boot CPU: err=%d\n", ret);
 506                 return ret;
 507         }
 508
 509         if (p == NULL || p->flight_plan == NULL || p->num_records < 1) {
 510                 printf("Invalid MP parameters\n");
 511                 return -1;
 512         }
 513
 514         num_cpus = cpu_get_count(cpu);
 515         if (num_cpus < 0) {
 516                 debug("Cannot get number of CPUs: err=%d\n", num_cpus);
 517                 return num_cpus;
 518         }
 519
 520         if (num_cpus < 2)
 521                 debug("Warning: Only 1 CPU is detected\n");
 522
 523         ret = check_cpu_devices(num_cpus);
 524         if (ret)
 525                 debug("Warning: Device tree does not describe all CPUs. Extra ones will not be started correctly\n");
 526
 527         /* Copy needed parameters so that APs have a reference to the plan */
 528         mp_info.num_records = p->num_records;
 529         mp_info.records = p->flight_plan;
 530
 531         /* Load the SIPI vector */
 532         ret = load_sipi_vector(&ap_count, num_cpus);
 533         if (ap_count == NULL)
 534                 return -1;
 535
 536         /*
 537          * Make sure SIPI data hits RAM so the APs that come up will see
 538          * the startup code even if the caches are disabled
 539          */
 540         wbinvd();
 541
 542         /* Start the APs providing number of APs and the cpus_entered field */
 543         num_aps = num_cpus - 1;
 544         ret = start_aps(num_aps, ap_count);
 545         if (ret) {
 546                 mdelay(1000);
 547                 debug("%d/%d eventually checked in?\n", atomic_read(ap_count),
 548                       num_aps);
 549                 return ret;
 550         }
 551
 552         /* Walk the flight plan for the BSP */
 553         ret = bsp_do_flight_plan(cpu, p);
 554         if (ret) {
 555                 debug("CPU init failed: err=%d\n", ret);
 556                 return ret;
 557         }
 558
 559         return 0;
 560 }
 561
 562 int mp_init_cpu(struct udevice *cpu, void *unused)
 563 {
 564         struct cpu_platdata *plat = dev_get_parent_platdata(cpu);
 565
 566         /*
 567          * Multiple APs are brought up simultaneously and they may get the same
 568          * seq num in the uclass_resolve_seq() during device_probe(). To avoid
 569          * this, set req_seq to the reg number in the device tree in advance.
 570          */
 571         cpu->req_seq = fdtdec_get_int(gd->fdt_blob, dev_of_offset(cpu), "reg",
 572                                       -1);
 573         plat->ucode_version = microcode_read_rev();
 574         plat->device_id = gd->arch.x86_device;
 575
 576         return device_probe(cpu);
 577 }