arch/x86/kernel/aperture_64.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Firmware replacement code.
   4  *
   5  * Work around broken BIOSes that don't set an aperture, only set the
   6  * aperture in the AGP bridge, or set too small aperture.
   7  *
   8  * If all fails map the aperture over some low memory.  This is cheaper than
   9  * doing bounce buffering. The memory is lost. This is done at early boot
  10  * because only the bootmem allocator can allocate 32+MB.
  11  *
  12  * Copyright 2002 Andi Kleen, SuSE Labs.
  13  */
  14 #define pr_fmt(fmt) "AGP: " fmt
  15
  16 #include <linux/kernel.h>
  17 #include <linux/kcore.h>
  18 #include <linux/types.h>
  19 #include <linux/init.h>
  20 #include <linux/memblock.h>
  21 #include <linux/mmzone.h>
  22 #include <linux/pci_ids.h>
  23 #include <linux/pci.h>
  24 #include <linux/bitops.h>
  25 #include <linux/suspend.h>
  26 #include <asm/e820/api.h>
  27 #include <asm/io.h>
  28 #include <asm/iommu.h>
  29 #include <asm/gart.h>
  30 #include <asm/pci-direct.h>
  31 #include <asm/dma.h>
  32 #include <asm/amd_nb.h>
  33 #include <asm/x86_init.h>
  34 #include <linux/crash_dump.h>
  35
  36 /*
  37  * Using 512M as goal, in case kexec will load kernel_big
  38  * that will do the on-position decompress, and could overlap with
  39  * with the gart aperture that is used.
  40  * Sequence:
  41  * kernel_small
  42  * ==> kexec (with kdump trigger path or gart still enabled)
  43  * ==> kernel_small (gart area become e820_reserved)
  44  * ==> kexec (with kdump trigger path or gart still enabled)
  45  * ==> kerne_big (uncompressed size will be big than 64M or 128M)
  46  * So don't use 512M below as gart iommu, leave the space for kernel
  47  * code for safe.
  48  */
  49 #define GART_MIN_ADDR   (512ULL << 20)
  50 #define GART_MAX_ADDR   (1ULL   << 32)
  51
  52 int gart_iommu_aperture;
  53 int gart_iommu_aperture_disabled __initdata;
  54 int gart_iommu_aperture_allowed __initdata;
  55
  56 int fallback_aper_order __initdata = 1; /* 64MB */
  57 int fallback_aper_force __initdata;
  58
  59 int fix_aperture __initdata = 1;
  60
  61 #if defined(CONFIG_PROC_VMCORE) || defined(CONFIG_PROC_KCORE)
  62 /*
  63  * If the first kernel maps the aperture over e820 RAM, the kdump kernel will
  64  * use the same range because it will remain configured in the northbridge.
  65  * Trying to dump this area via /proc/vmcore may crash the machine, so exclude
  66  * it from vmcore.
  67  */
  68 static unsigned long aperture_pfn_start, aperture_page_count;
  69
  70 static int gart_mem_pfn_is_ram(unsigned long pfn)
  71 {
  72         return likely((pfn < aperture_pfn_start) ||
  73                       (pfn >= aperture_pfn_start + aperture_page_count));
  74 }
  75
  76 static void __init exclude_from_core(u64 aper_base, u32 aper_order)
  77 {
  78         aperture_pfn_start = aper_base >> PAGE_SHIFT;
  79         aperture_page_count = (32 * 1024 * 1024) << aper_order >> PAGE_SHIFT;
  80 #ifdef CONFIG_PROC_VMCORE
  81         WARN_ON(register_oldmem_pfn_is_ram(&gart_mem_pfn_is_ram));
  82 #endif
  83 #ifdef CONFIG_PROC_KCORE
  84         WARN_ON(register_mem_pfn_is_ram(&gart_mem_pfn_is_ram));
  85 #endif
  86 }
  87 #else
  88 static void exclude_from_core(u64 aper_base, u32 aper_order)
  89 {
  90 }
  91 #endif
  92
  93 /* This code runs before the PCI subsystem is initialized, so just
  94    access the northbridge directly. */
  95
  96 static u32 __init allocate_aperture(void)
  97 {
  98         u32 aper_size;
  99         unsigned long addr;
 100
 101         /* aper_size should <= 1G */
 102         if (fallback_aper_order > 5)
 103                 fallback_aper_order = 5;
 104         aper_size = (32 * 1024 * 1024) << fallback_aper_order;
 105
 106         /*
 107          * Aperture has to be naturally aligned. This means a 2GB aperture
 108          * won't have much chance of finding a place in the lower 4GB of
 109          * memory. Unfortunately we cannot move it up because that would
 110          * make the IOMMU useless.
 111          */
 112         addr = memblock_find_in_range(GART_MIN_ADDR, GART_MAX_ADDR,
 113                                       aper_size, aper_size);
 114         if (!addr) {
 115                 pr_err("Cannot allocate aperture memory hole [mem %#010lx-%#010lx] (%uKB)\n",
 116                        addr, addr + aper_size - 1, aper_size >> 10);
 117                 return 0;
 118         }
 119         memblock_reserve(addr, aper_size);
 120         pr_info("Mapping aperture over RAM [mem %#010lx-%#010lx] (%uKB)\n",
 121                 addr, addr + aper_size - 1, aper_size >> 10);
 122         register_nosave_region(addr >> PAGE_SHIFT,
 123                                (addr+aper_size) >> PAGE_SHIFT);
 124
 125         return (u32)addr;
 126 }
 127
 128
 129 /* Find a PCI capability */
 130 static u32 __init find_cap(int bus, int slot, int func, int cap)
 131 {
 132         int bytes;
 133         u8 pos;
 134
 135         if (!(read_pci_config_16(bus, slot, func, PCI_STATUS) &
 136                                                 PCI_STATUS_CAP_LIST))
 137                 return 0;
 138
 139         pos = read_pci_config_byte(bus, slot, func, PCI_CAPABILITY_LIST);
 140         for (bytes = 0; bytes < 48 && pos >= 0x40; bytes++) {
 141                 u8 id;
 142
 143                 pos &= ~3;
 144                 id = read_pci_config_byte(bus, slot, func, pos+PCI_CAP_LIST_ID);
 145                 if (id == 0xff)
 146                         break;
 147                 if (id == cap)
 148                         return pos;
 149                 pos = read_pci_config_byte(bus, slot, func,
 150                                                 pos+PCI_CAP_LIST_NEXT);
 151         }
 152         return 0;
 153 }
 154
 155 /* Read a standard AGPv3 bridge header */
 156 static u32 __init read_agp(int bus, int slot, int func, int cap, u32 *order)
 157 {
 158         u32 apsize;
 159         u32 apsizereg;
 160         int nbits;
 161         u32 aper_low, aper_hi;
 162         u64 aper;
 163         u32 old_order;
 164
 165         pr_info("pci 0000:%02x:%02x:%02x: AGP bridge\n", bus, slot, func);
 166         apsizereg = read_pci_config_16(bus, slot, func, cap + 0x14);
 167         if (apsizereg == 0xffffffff) {
 168                 pr_err("pci 0000:%02x:%02x.%d: APSIZE unreadable\n",
 169                        bus, slot, func);
 170                 return 0;
 171         }
 172
 173         /* old_order could be the value from NB gart setting */
 174         old_order = *order;
 175
 176         apsize = apsizereg & 0xfff;
 177         /* Some BIOS use weird encodings not in the AGPv3 table. */
 178         if (apsize & 0xff)
 179                 apsize |= 0xf00;
 180         nbits = hweight16(apsize);
 181         *order = 7 - nbits;
 182         if ((int)*order < 0) /* < 32MB */
 183                 *order = 0;
 184
 185         aper_low = read_pci_config(bus, slot, func, 0x10);
 186         aper_hi = read_pci_config(bus, slot, func, 0x14);
 187         aper = (aper_low & ~((1<<22)-1)) | ((u64)aper_hi << 32);
 188
 189         /*
 190          * On some sick chips, APSIZE is 0. It means it wants 4G
 191          * so let double check that order, and lets trust AMD NB settings:
 192          */
 193         pr_info("pci 0000:%02x:%02x.%d: AGP aperture [bus addr %#010Lx-%#010Lx] (old size %uMB)\n",
 194                 bus, slot, func, aper, aper + (32ULL << (old_order + 20)) - 1,
 195                 32 << old_order);
 196         if (aper + (32ULL<<(20 + *order)) > 0x100000000ULL) {
 197                 pr_info("pci 0000:%02x:%02x.%d: AGP aperture size %uMB (APSIZE %#x) is not right, using settings from NB\n",
 198                         bus, slot, func, 32 << *order, apsizereg);
 199                 *order = old_order;
 200         }
 201
 202         pr_info("pci 0000:%02x:%02x.%d: AGP aperture [bus addr %#010Lx-%#010Lx] (%uMB, APSIZE %#x)\n",
 203                 bus, slot, func, aper, aper + (32ULL << (*order + 20)) - 1,
 204                 32 << *order, apsizereg);
 205
 206         if (!aperture_valid(aper, (32*1024*1024) << *order, 32<<20))
 207                 return 0;
 208         return (u32)aper;
 209 }
 210
 211 /*
 212  * Look for an AGP bridge. Windows only expects the aperture in the
 213  * AGP bridge and some BIOS forget to initialize the Northbridge too.
 214  * Work around this here.
 215  *
 216  * Do an PCI bus scan by hand because we're running before the PCI
 217  * subsystem.
 218  *
 219  * All AMD AGP bridges are AGPv3 compliant, so we can do this scan
 220  * generically. It's probably overkill to always scan all slots because
 221  * the AGP bridges should be always an own bus on the HT hierarchy,
 222  * but do it here for future safety.
 223  */
 224 static u32 __init search_agp_bridge(u32 *order, int *valid_agp)
 225 {
 226         int bus, slot, func;
 227
 228         /* Poor man's PCI discovery */
 229         for (bus = 0; bus < 256; bus++) {
 230                 for (slot = 0; slot < 32; slot++) {
 231                         for (func = 0; func < 8; func++) {
 232                                 u32 class, cap;
 233                                 u8 type;
 234                                 class = read_pci_config(bus, slot, func,
 235                                                         PCI_CLASS_REVISION);
 236                                 if (class == 0xffffffff)
 237                                         break;
 238
 239                                 switch (class >> 16) {
 240                                 case PCI_CLASS_BRIDGE_HOST:
 241                                 case PCI_CLASS_BRIDGE_OTHER: /* needed? */
 242                                         /* AGP bridge? */
 243                                         cap = find_cap(bus, slot, func,
 244                                                         PCI_CAP_ID_AGP);
 245                                         if (!cap)
 246                                                 break;
 247                                         *valid_agp = 1;
 248                                         return read_agp(bus, slot, func, cap,
 249                                                         order);
 250                                 }
 251
 252                                 /* No multi-function device? */
 253                                 type = read_pci_config_byte(bus, slot, func,
 254                                                                PCI_HEADER_TYPE);
 255                                 if (!(type & 0x80))
 256                                         break;
 257                         }
 258                 }
 259         }
 260         pr_info("No AGP bridge found\n");
 261
 262         return 0;
 263 }
 264
 265 static bool gart_fix_e820 __initdata = true;
 266
 267 static int __init parse_gart_mem(char *p)
 268 {
 269         return kstrtobool(p, &gart_fix_e820);
 270 }
 271 early_param("gart_fix_e820", parse_gart_mem);
 272
 273 /*
 274  * With kexec/kdump, if the first kernel doesn't shut down the GART and the
 275  * second kernel allocates a different GART region, there might be two
 276  * overlapping GART regions present:
 277  *
 278  * - the first still used by the GART initialized in the first kernel.
 279  * - (sub-)set of it used as normal RAM by the second kernel.
 280  *
 281  * which leads to memory corruptions and a kernel panic eventually.
 282  *
 283  * This can also happen if the BIOS has forgotten to mark the GART region
 284  * as reserved.
 285  *
 286  * Try to update the e820 map to mark that new region as reserved.
 287  */
 288 void __init early_gart_iommu_check(void)
 289 {
 290         u32 agp_aper_order = 0;
 291         int i, fix, slot, valid_agp = 0;
 292         u32 ctl;
 293         u32 aper_size = 0, aper_order = 0, last_aper_order = 0;
 294         u64 aper_base = 0, last_aper_base = 0;
 295         int aper_enabled = 0, last_aper_enabled = 0, last_valid = 0;
 296
 297         if (!amd_gart_present())
 298                 return;
 299
 300         if (!early_pci_allowed())
 301                 return;
 302
 303         /* This is mostly duplicate of iommu_hole_init */
 304         search_agp_bridge(&agp_aper_order, &valid_agp);
 305
 306         fix = 0;
 307         for (i = 0; amd_nb_bus_dev_ranges[i].dev_limit; i++) {
 308                 int bus;
 309                 int dev_base, dev_limit;
 310
 311                 bus = amd_nb_bus_dev_ranges[i].bus;
 312                 dev_base = amd_nb_bus_dev_ranges[i].dev_base;
 313                 dev_limit = amd_nb_bus_dev_ranges[i].dev_limit;
 314
 315                 for (slot = dev_base; slot < dev_limit; slot++) {
 316                         if (!early_is_amd_nb(read_pci_config(bus, slot, 3, 0x00)))
 317                                 continue;
 318
 319                         ctl = read_pci_config(bus, slot, 3, AMD64_GARTAPERTURECTL);
 320                         aper_enabled = ctl & GARTEN;
 321                         aper_order = (ctl >> 1) & 7;
 322                         aper_size = (32 * 1024 * 1024) << aper_order;
 323                         aper_base = read_pci_config(bus, slot, 3, AMD64_GARTAPERTUREBASE) & 0x7fff;
 324                         aper_base <<= 25;
 325
 326                         if (last_valid) {
 327                                 if ((aper_order != last_aper_order) ||
 328                                     (aper_base != last_aper_base) ||
 329                                     (aper_enabled != last_aper_enabled)) {
 330                                         fix = 1;
 331                                         break;
 332                                 }
 333                         }
 334
 335                         last_aper_order = aper_order;
 336                         last_aper_base = aper_base;
 337                         last_aper_enabled = aper_enabled;
 338                         last_valid = 1;
 339                 }
 340         }
 341
 342         if (!fix && !aper_enabled)
 343                 return;
 344
 345         if (!aper_base || !aper_size || aper_base + aper_size > 0x100000000UL)
 346                 fix = 1;
 347
 348         if (gart_fix_e820 && !fix && aper_enabled) {
 349                 if (e820__mapped_any(aper_base, aper_base + aper_size,
 350                                     E820_TYPE_RAM)) {
 351                         /* reserve it, so we can reuse it in second kernel */
 352                         pr_info("e820: reserve [mem %#010Lx-%#010Lx] for GART\n",
 353                                 aper_base, aper_base + aper_size - 1);
 354                         e820__range_add(aper_base, aper_size, E820_TYPE_RESERVED);
 355                         e820__update_table_print();
 356                 }
 357         }
 358
 359         if (valid_agp)
 360                 return;
 361
 362         /* disable them all at first */
 363         for (i = 0; i < amd_nb_bus_dev_ranges[i].dev_limit; i++) {
 364                 int bus;
 365                 int dev_base, dev_limit;
 366
 367                 bus = amd_nb_bus_dev_ranges[i].bus;
 368                 dev_base = amd_nb_bus_dev_ranges[i].dev_base;
 369                 dev_limit = amd_nb_bus_dev_ranges[i].dev_limit;
 370
 371                 for (slot = dev_base; slot < dev_limit; slot++) {
 372                         if (!early_is_amd_nb(read_pci_config(bus, slot, 3, 0x00)))
 373                                 continue;
 374
 375                         ctl = read_pci_config(bus, slot, 3, AMD64_GARTAPERTURECTL);
 376                         ctl &= ~GARTEN;
 377                         write_pci_config(bus, slot, 3, AMD64_GARTAPERTURECTL, ctl);
 378                 }
 379         }
 380
 381 }
 382
 383 static int __initdata printed_gart_size_msg;
 384
 385 int __init gart_iommu_hole_init(void)
 386 {
 387         u32 agp_aper_base = 0, agp_aper_order = 0;
 388         u32 aper_size, aper_alloc = 0, aper_order = 0, last_aper_order = 0;
 389         u64 aper_base, last_aper_base = 0;
 390         int fix, slot, valid_agp = 0;
 391         int i, node;
 392
 393         if (!amd_gart_present())
 394                 return -ENODEV;
 395
 396         if (gart_iommu_aperture_disabled || !fix_aperture ||
 397             !early_pci_allowed())
 398                 return -ENODEV;
 399
 400         pr_info("Checking aperture...\n");
 401
 402         if (!fallback_aper_force)
 403                 agp_aper_base = search_agp_bridge(&agp_aper_order, &valid_agp);
 404
 405         fix = 0;
 406         node = 0;
 407         for (i = 0; i < amd_nb_bus_dev_ranges[i].dev_limit; i++) {
 408                 int bus;
 409                 int dev_base, dev_limit;
 410                 u32 ctl;
 411
 412                 bus = amd_nb_bus_dev_ranges[i].bus;
 413                 dev_base = amd_nb_bus_dev_ranges[i].dev_base;
 414                 dev_limit = amd_nb_bus_dev_ranges[i].dev_limit;
 415
 416                 for (slot = dev_base; slot < dev_limit; slot++) {
 417                         if (!early_is_amd_nb(read_pci_config(bus, slot, 3, 0x00)))
 418                                 continue;
 419
 420                         iommu_detected = 1;
 421                         gart_iommu_aperture = 1;
 422                         x86_init.iommu.iommu_init = gart_iommu_init;
 423
 424                         ctl = read_pci_config(bus, slot, 3,
 425                                               AMD64_GARTAPERTURECTL);
 426
 427                         /*
 428                          * Before we do anything else disable the GART. It may
 429                          * still be enabled if we boot into a crash-kernel here.
 430                          * Reconfiguring the GART while it is enabled could have
 431                          * unknown side-effects.
 432                          */
 433                         ctl &= ~GARTEN;
 434                         write_pci_config(bus, slot, 3, AMD64_GARTAPERTURECTL, ctl);
 435
 436                         aper_order = (ctl >> 1) & 7;
 437                         aper_size = (32 * 1024 * 1024) << aper_order;
 438                         aper_base = read_pci_config(bus, slot, 3, AMD64_GARTAPERTUREBASE) & 0x7fff;
 439                         aper_base <<= 25;
 440
 441                         pr_info("Node %d: aperture [bus addr %#010Lx-%#010Lx] (%uMB)\n",
 442                                 node, aper_base, aper_base + aper_size - 1,
 443                                 aper_size >> 20);
 444                         node++;
 445
 446                         if (!aperture_valid(aper_base, aper_size, 64<<20)) {
 447                                 if (valid_agp && agp_aper_base &&
 448                                     agp_aper_base == aper_base &&
 449                                     agp_aper_order == aper_order) {
 450                                         /* the same between two setting from NB and agp */
 451                                         if (!no_iommu &&
 452                                             max_pfn > MAX_DMA32_PFN &&
 453                                             !printed_gart_size_msg) {
 454                                                 pr_err("you are using iommu with agp, but GART size is less than 64MB\n");
 455                                                 pr_err("please increase GART size in your BIOS setup\n");
 456                                                 pr_err("if BIOS doesn't have that option, contact your HW vendor!\n");
 457                                                 printed_gart_size_msg = 1;
 458                                         }
 459                                 } else {
 460                                         fix = 1;
 461                                         goto out;
 462                                 }
 463                         }
 464
 465                         if ((last_aper_order && aper_order != last_aper_order) ||
 466                             (last_aper_base && aper_base != last_aper_base)) {
 467                                 fix = 1;
 468                                 goto out;
 469                         }
 470                         last_aper_order = aper_order;
 471                         last_aper_base = aper_base;
 472                 }
 473         }
 474
 475 out:
 476         if (!fix && !fallback_aper_force) {
 477                 if (last_aper_base) {
 478                         /*
 479                          * If this is the kdump kernel, the first kernel
 480                          * may have allocated the range over its e820 RAM
 481                          * and fixed up the northbridge
 482                          */
 483                         exclude_from_core(last_aper_base, last_aper_order);
 484
 485                         return 1;
 486                 }
 487                 return 0;
 488         }
 489
 490         if (!fallback_aper_force) {
 491                 aper_alloc = agp_aper_base;
 492                 aper_order = agp_aper_order;
 493         }
 494
 495         if (aper_alloc) {
 496                 /* Got the aperture from the AGP bridge */
 497         } else if ((!no_iommu && max_pfn > MAX_DMA32_PFN) ||
 498                    force_iommu ||
 499                    valid_agp ||
 500                    fallback_aper_force) {
 501                 pr_info("Your BIOS doesn't leave an aperture memory hole\n");
 502                 pr_info("Please enable the IOMMU option in the BIOS setup\n");
 503                 pr_info("This costs you %dMB of RAM\n",
 504                         32 << fallback_aper_order);
 505
 506                 aper_order = fallback_aper_order;
 507                 aper_alloc = allocate_aperture();
 508                 if (!aper_alloc) {
 509                         /*
 510                          * Could disable AGP and IOMMU here, but it's
 511                          * probably not worth it. But the later users
 512                          * cannot deal with bad apertures and turning
 513                          * on the aperture over memory causes very
 514                          * strange problems, so it's better to panic
 515                          * early.
 516                          */
 517                         panic("Not enough memory for aperture");
 518                 }
 519         } else {
 520                 return 0;
 521         }
 522
 523         /*
 524          * If this is the kdump kernel _and_ the first kernel did not
 525          * configure the aperture in the northbridge, this range may
 526          * overlap with the first kernel's memory. We can't access the
 527          * range through vmcore even though it should be part of the dump.
 528          */
 529         exclude_from_core(aper_alloc, aper_order);
 530
 531         /* Fix up the north bridges */
 532         for (i = 0; i < amd_nb_bus_dev_ranges[i].dev_limit; i++) {
 533                 int bus, dev_base, dev_limit;
 534
 535                 /*
 536                  * Don't enable translation yet but enable GART IO and CPU
 537                  * accesses and set DISTLBWALKPRB since GART table memory is UC.
 538                  */
 539                 u32 ctl = aper_order << 1;
 540
 541                 bus = amd_nb_bus_dev_ranges[i].bus;
 542                 dev_base = amd_nb_bus_dev_ranges[i].dev_base;
 543                 dev_limit = amd_nb_bus_dev_ranges[i].dev_limit;
 544                 for (slot = dev_base; slot < dev_limit; slot++) {
 545                         if (!early_is_amd_nb(read_pci_config(bus, slot, 3, 0x00)))
 546                                 continue;
 547
 548                         write_pci_config(bus, slot, 3, AMD64_GARTAPERTURECTL, ctl);
 549                         write_pci_config(bus, slot, 3, AMD64_GARTAPERTUREBASE, aper_alloc >> 25);
 550                 }
 551         }
 552
 553         set_up_gart_resume(aper_order, aper_alloc);
 554
 555         return 1;
 556 }