arch/ia64/mm/init.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Initialize MMU support.
   4  *
   5  * Copyright (C) 1998-2003 Hewlett-Packard Co
   6  *      David Mosberger-Tang <davidm@hpl.hp.com>
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/init.h>
  10
  11 #include <linux/dma-map-ops.h>
  12 #include <linux/dmar.h>
  13 #include <linux/efi.h>
  14 #include <linux/elf.h>
  15 #include <linux/memblock.h>
  16 #include <linux/mm.h>
  17 #include <linux/sched/signal.h>
  18 #include <linux/mmzone.h>
  19 #include <linux/module.h>
  20 #include <linux/personality.h>
  21 #include <linux/reboot.h>
  22 #include <linux/slab.h>
  23 #include <linux/swap.h>
  24 #include <linux/proc_fs.h>
  25 #include <linux/bitops.h>
  26 #include <linux/kexec.h>
  27 #include <linux/swiotlb.h>
  28
  29 #include <asm/dma.h>
  30 #include <asm/io.h>
  31 #include <asm/numa.h>
  32 #include <asm/patch.h>
  33 #include <asm/pgalloc.h>
  34 #include <asm/sal.h>
  35 #include <asm/sections.h>
  36 #include <asm/tlb.h>
  37 #include <linux/uaccess.h>
  38 #include <asm/unistd.h>
  39 #include <asm/mca.h>
  40
  41 extern void ia64_tlb_init (void);
  42
  43 unsigned long MAX_DMA_ADDRESS = PAGE_OFFSET + 0x100000000UL;
  44
  45 #ifdef CONFIG_VIRTUAL_MEM_MAP
  46 unsigned long VMALLOC_END = VMALLOC_END_INIT;
  47 EXPORT_SYMBOL(VMALLOC_END);
  48 struct page *vmem_map;
  49 EXPORT_SYMBOL(vmem_map);
  50 #endif
  51
  52 struct page *zero_page_memmap_ptr;      /* map entry for zero page */
  53 EXPORT_SYMBOL(zero_page_memmap_ptr);
  54
  55 void
  56 __ia64_sync_icache_dcache (pte_t pte)
  57 {
  58         unsigned long addr;
  59         struct page *page;
  60
  61         page = pte_page(pte);
  62         addr = (unsigned long) page_address(page);
  63
  64         if (test_bit(PG_arch_1, &page->flags))
  65                 return;                         /* i-cache is already coherent with d-cache */
  66
  67         flush_icache_range(addr, addr + page_size(page));
  68         set_bit(PG_arch_1, &page->flags);       /* mark page as clean */
  69 }
  70
  71 /*
  72  * Since DMA is i-cache coherent, any (complete) pages that were written via
  73  * DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to
  74  * flush them when they get mapped into an executable vm-area.
  75  */
  76 void arch_dma_mark_clean(phys_addr_t paddr, size_t size)
  77 {
  78         unsigned long pfn = PHYS_PFN(paddr);
  79
  80         do {
  81                 set_bit(PG_arch_1, &pfn_to_page(pfn)->flags);
  82         } while (++pfn <= PHYS_PFN(paddr + size - 1));
  83 }
  84
  85 inline void
  86 ia64_set_rbs_bot (void)
  87 {
  88         unsigned long stack_size = rlimit_max(RLIMIT_STACK) & -16;
  89
  90         if (stack_size > MAX_USER_STACK_SIZE)
  91                 stack_size = MAX_USER_STACK_SIZE;
  92         current->thread.rbs_bot = PAGE_ALIGN(current->mm->start_stack - stack_size);
  93 }
  94
  95 /*
  96  * This performs some platform-dependent address space initialization.
  97  * On IA-64, we want to setup the VM area for the register backing
  98  * store (which grows upwards) and install the gateway page which is
  99  * used for signal trampolines, etc.
 100  */
 101 void
 102 ia64_init_addr_space (void)
 103 {
 104         struct vm_area_struct *vma;
 105
 106         ia64_set_rbs_bot();
 107
 108         /*
 109          * If we're out of memory and kmem_cache_alloc() returns NULL, we simply ignore
 110          * the problem.  When the process attempts to write to the register backing store
 111          * for the first time, it will get a SEGFAULT in this case.
 112          */
 113         vma = vm_area_alloc(current->mm);
 114         if (vma) {
 115                 vma_set_anonymous(vma);
 116                 vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
 117                 vma->vm_end = vma->vm_start + PAGE_SIZE;
 118                 vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
 119                 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 120                 mmap_write_lock(current->mm);
 121                 if (insert_vm_struct(current->mm, vma)) {
 122                         mmap_write_unlock(current->mm);
 123                         vm_area_free(vma);
 124                         return;
 125                 }
 126                 mmap_write_unlock(current->mm);
 127         }
 128
 129         /* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
 130         if (!(current->personality & MMAP_PAGE_ZERO)) {
 131                 vma = vm_area_alloc(current->mm);
 132                 if (vma) {
 133                         vma_set_anonymous(vma);
 134                         vma->vm_end = PAGE_SIZE;
 135                         vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
 136                         vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
 137                                         VM_DONTEXPAND | VM_DONTDUMP;
 138                         mmap_write_lock(current->mm);
 139                         if (insert_vm_struct(current->mm, vma)) {
 140                                 mmap_write_unlock(current->mm);
 141                                 vm_area_free(vma);
 142                                 return;
 143                         }
 144                         mmap_write_unlock(current->mm);
 145                 }
 146         }
 147 }
 148
 149 void
 150 free_initmem (void)
 151 {
 152         free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
 153                            -1, "unused kernel");
 154 }
 155
 156 void __init
 157 free_initrd_mem (unsigned long start, unsigned long end)
 158 {
 159         /*
 160          * EFI uses 4KB pages while the kernel can use 4KB or bigger.
 161          * Thus EFI and the kernel may have different page sizes. It is
 162          * therefore possible to have the initrd share the same page as
 163          * the end of the kernel (given current setup).
 164          *
 165          * To avoid freeing/using the wrong page (kernel sized) we:
 166          *      - align up the beginning of initrd
 167          *      - align down the end of initrd
 168          *
 169          *  |             |
 170          *  |=============| a000
 171          *  |             |
 172          *  |             |
 173          *  |             | 9000
 174          *  |/////////////|
 175          *  |/////////////|
 176          *  |=============| 8000
 177          *  |///INITRD////|
 178          *  |/////////////|
 179          *  |/////////////| 7000
 180          *  |             |
 181          *  |KKKKKKKKKKKKK|
 182          *  |=============| 6000
 183          *  |KKKKKKKKKKKKK|
 184          *  |KKKKKKKKKKKKK|
 185          *  K=kernel using 8KB pages
 186          *
 187          * In this example, we must free page 8000 ONLY. So we must align up
 188          * initrd_start and keep initrd_end as is.
 189          */
 190         start = PAGE_ALIGN(start);
 191         end = end & PAGE_MASK;
 192
 193         if (start < end)
 194                 printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);
 195
 196         for (; start < end; start += PAGE_SIZE) {
 197                 if (!virt_addr_valid(start))
 198                         continue;
 199                 free_reserved_page(virt_to_page(start));
 200         }
 201 }
 202
 203 /*
 204  * This installs a clean page in the kernel's page table.
 205  */
 206 static struct page * __init
 207 put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
 208 {
 209         pgd_t *pgd;
 210         p4d_t *p4d;
 211         pud_t *pud;
 212         pmd_t *pmd;
 213         pte_t *pte;
 214
 215         pgd = pgd_offset_k(address);            /* note: this is NOT pgd_offset()! */
 216
 217         {
 218                 p4d = p4d_alloc(&init_mm, pgd, address);
 219                 if (!p4d)
 220                         goto out;
 221                 pud = pud_alloc(&init_mm, p4d, address);
 222                 if (!pud)
 223                         goto out;
 224                 pmd = pmd_alloc(&init_mm, pud, address);
 225                 if (!pmd)
 226                         goto out;
 227                 pte = pte_alloc_kernel(pmd, address);
 228                 if (!pte)
 229                         goto out;
 230                 if (!pte_none(*pte))
 231                         goto out;
 232                 set_pte(pte, mk_pte(page, pgprot));
 233         }
 234   out:
 235         /* no need for flush_tlb */
 236         return page;
 237 }
 238
 239 static void __init
 240 setup_gate (void)
 241 {
 242         struct page *page;
 243
 244         /*
 245          * Map the gate page twice: once read-only to export the ELF
 246          * headers etc. and once execute-only page to enable
 247          * privilege-promotion via "epc":
 248          */
 249         page = virt_to_page(ia64_imva(__start_gate_section));
 250         put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
 251 #ifdef HAVE_BUGGY_SEGREL
 252         page = virt_to_page(ia64_imva(__start_gate_section + PAGE_SIZE));
 253         put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
 254 #else
 255         put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
 256         /* Fill in the holes (if any) with read-only zero pages: */
 257         {
 258                 unsigned long addr;
 259
 260                 for (addr = GATE_ADDR + PAGE_SIZE;
 261                      addr < GATE_ADDR + PERCPU_PAGE_SIZE;
 262                      addr += PAGE_SIZE)
 263                 {
 264                         put_kernel_page(ZERO_PAGE(0), addr,
 265                                         PAGE_READONLY);
 266                         put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
 267                                         PAGE_READONLY);
 268                 }
 269         }
 270 #endif
 271         ia64_patch_gate();
 272 }
 273
 274 static struct vm_area_struct gate_vma;
 275
 276 static int __init gate_vma_init(void)
 277 {
 278         vma_init(&gate_vma, NULL);
 279         gate_vma.vm_start = FIXADDR_USER_START;
 280         gate_vma.vm_end = FIXADDR_USER_END;
 281         gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
 282         gate_vma.vm_page_prot = __P101;
 283
 284         return 0;
 285 }
 286 __initcall(gate_vma_init);
 287
 288 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 289 {
 290         return &gate_vma;
 291 }
 292
 293 int in_gate_area_no_mm(unsigned long addr)
 294 {
 295         if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
 296                 return 1;
 297         return 0;
 298 }
 299
 300 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 301 {
 302         return in_gate_area_no_mm(addr);
 303 }
 304
 305 void ia64_mmu_init(void *my_cpu_data)
 306 {
 307         unsigned long pta, impl_va_bits;
 308         extern void tlb_init(void);
 309
 310 #ifdef CONFIG_DISABLE_VHPT
 311 #       define VHPT_ENABLE_BIT  0
 312 #else
 313 #       define VHPT_ENABLE_BIT  1
 314 #endif
 315
 316         /*
 317          * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
 318          * address space.  The IA-64 architecture guarantees that at least 50 bits of
 319          * virtual address space are implemented but if we pick a large enough page size
 320          * (e.g., 64KB), the mapped address space is big enough that it will overlap with
 321          * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
 322          * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
 323          * problem in practice.  Alternatively, we could truncate the top of the mapped
 324          * address space to not permit mappings that would overlap with the VMLPT.
 325          * --davidm 00/12/06
 326          */
 327 #       define pte_bits                 3
 328 #       define mapped_space_bits        (3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
 329         /*
 330          * The virtual page table has to cover the entire implemented address space within
 331          * a region even though not all of this space may be mappable.  The reason for
 332          * this is that the Access bit and Dirty bit fault handlers perform
 333          * non-speculative accesses to the virtual page table, so the address range of the
 334          * virtual page table itself needs to be covered by virtual page table.
 335          */
 336 #       define vmlpt_bits               (impl_va_bits - PAGE_SHIFT + pte_bits)
 337 #       define POW2(n)                  (1ULL << (n))
 338
 339         impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));
 340
 341         if (impl_va_bits < 51 || impl_va_bits > 61)
 342                 panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
 343         /*
 344          * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
 345          * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
 346          * the test makes sure that our mapped space doesn't overlap the
 347          * unimplemented hole in the middle of the region.
 348          */
 349         if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
 350             (mapped_space_bits > impl_va_bits - 1))
 351                 panic("Cannot build a big enough virtual-linear page table"
 352                       " to cover mapped address space.\n"
 353                       " Try using a smaller page size.\n");
 354
 355
 356         /* place the VMLPT at the end of each page-table mapped region: */
 357         pta = POW2(61) - POW2(vmlpt_bits);
 358
 359         /*
 360          * Set the (virtually mapped linear) page table address.  Bit
 361          * 8 selects between the short and long format, bits 2-7 the
 362          * size of the table, and bit 0 whether the VHPT walker is
 363          * enabled.
 364          */
 365         ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);
 366
 367         ia64_tlb_init();
 368
 369 #ifdef  CONFIG_HUGETLB_PAGE
 370         ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
 371         ia64_srlz_d();
 372 #endif
 373 }
 374
 375 #ifdef CONFIG_VIRTUAL_MEM_MAP
 376 int vmemmap_find_next_valid_pfn(int node, int i)
 377 {
 378         unsigned long end_address, hole_next_pfn;
 379         unsigned long stop_address;
 380         pg_data_t *pgdat = NODE_DATA(node);
 381
 382         end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
 383         end_address = PAGE_ALIGN(end_address);
 384         stop_address = (unsigned long) &vmem_map[pgdat_end_pfn(pgdat)];
 385
 386         do {
 387                 pgd_t *pgd;
 388                 p4d_t *p4d;
 389                 pud_t *pud;
 390                 pmd_t *pmd;
 391                 pte_t *pte;
 392
 393                 pgd = pgd_offset_k(end_address);
 394                 if (pgd_none(*pgd)) {
 395                         end_address += PGDIR_SIZE;
 396                         continue;
 397                 }
 398
 399                 p4d = p4d_offset(pgd, end_address);
 400                 if (p4d_none(*p4d)) {
 401                         end_address += P4D_SIZE;
 402                         continue;
 403                 }
 404
 405                 pud = pud_offset(p4d, end_address);
 406                 if (pud_none(*pud)) {
 407                         end_address += PUD_SIZE;
 408                         continue;
 409                 }
 410
 411                 pmd = pmd_offset(pud, end_address);
 412                 if (pmd_none(*pmd)) {
 413                         end_address += PMD_SIZE;
 414                         continue;
 415                 }
 416
 417                 pte = pte_offset_kernel(pmd, end_address);
 418 retry_pte:
 419                 if (pte_none(*pte)) {
 420                         end_address += PAGE_SIZE;
 421                         pte++;
 422                         if ((end_address < stop_address) &&
 423                             (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
 424                                 goto retry_pte;
 425                         continue;
 426                 }
 427                 /* Found next valid vmem_map page */
 428                 break;
 429         } while (end_address < stop_address);
 430
 431         end_address = min(end_address, stop_address);
 432         end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
 433         hole_next_pfn = end_address / sizeof(struct page);
 434         return hole_next_pfn - pgdat->node_start_pfn;
 435 }
 436
 437 int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
 438 {
 439         unsigned long address, start_page, end_page;
 440         struct page *map_start, *map_end;
 441         int node;
 442         pgd_t *pgd;
 443         p4d_t *p4d;
 444         pud_t *pud;
 445         pmd_t *pmd;
 446         pte_t *pte;
 447
 448         map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
 449         map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
 450
 451         start_page = (unsigned long) map_start & PAGE_MASK;
 452         end_page = PAGE_ALIGN((unsigned long) map_end);
 453         node = paddr_to_nid(__pa(start));
 454
 455         for (address = start_page; address < end_page; address += PAGE_SIZE) {
 456                 pgd = pgd_offset_k(address);
 457                 if (pgd_none(*pgd)) {
 458                         p4d = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
 459                         if (!p4d)
 460                                 goto err_alloc;
 461                         pgd_populate(&init_mm, pgd, p4d);
 462                 }
 463                 p4d = p4d_offset(pgd, address);
 464
 465                 if (p4d_none(*p4d)) {
 466                         pud = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
 467                         if (!pud)
 468                                 goto err_alloc;
 469                         p4d_populate(&init_mm, p4d, pud);
 470                 }
 471                 pud = pud_offset(p4d, address);
 472
 473                 if (pud_none(*pud)) {
 474                         pmd = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
 475                         if (!pmd)
 476                                 goto err_alloc;
 477                         pud_populate(&init_mm, pud, pmd);
 478                 }
 479                 pmd = pmd_offset(pud, address);
 480
 481                 if (pmd_none(*pmd)) {
 482                         pte = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
 483                         if (!pte)
 484                                 goto err_alloc;
 485                         pmd_populate_kernel(&init_mm, pmd, pte);
 486                 }
 487                 pte = pte_offset_kernel(pmd, address);
 488
 489                 if (pte_none(*pte)) {
 490                         void *page = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE,
 491                                                          node);
 492                         if (!page)
 493                                 goto err_alloc;
 494                         set_pte(pte, pfn_pte(__pa(page) >> PAGE_SHIFT,
 495                                              PAGE_KERNEL));
 496                 }
 497         }
 498         return 0;
 499
 500 err_alloc:
 501         panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d\n",
 502               __func__, PAGE_SIZE, PAGE_SIZE, node);
 503         return -ENOMEM;
 504 }
 505
 506 struct memmap_init_callback_data {
 507         struct page *start;
 508         struct page *end;
 509         int nid;
 510         unsigned long zone;
 511 };
 512
 513 static int __meminit
 514 virtual_memmap_init(u64 start, u64 end, void *arg)
 515 {
 516         struct memmap_init_callback_data *args;
 517         struct page *map_start, *map_end;
 518
 519         args = (struct memmap_init_callback_data *) arg;
 520         map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
 521         map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
 522
 523         if (map_start < args->start)
 524                 map_start = args->start;
 525         if (map_end > args->end)
 526                 map_end = args->end;
 527
 528         /*
 529          * We have to initialize "out of bounds" struct page elements that fit completely
 530          * on the same pages that were allocated for the "in bounds" elements because they
 531          * may be referenced later (and found to be "reserved").
 532          */
 533         map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
 534         map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
 535                     / sizeof(struct page));
 536
 537         if (map_start < map_end)
 538                 memmap_init_zone((unsigned long)(map_end - map_start),
 539                                  args->nid, args->zone, page_to_pfn(map_start),
 540                                  MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
 541         return 0;
 542 }
 543
 544 void __meminit
 545 memmap_init (unsigned long size, int nid, unsigned long zone,
 546              unsigned long start_pfn)
 547 {
 548         if (!vmem_map) {
 549                 memmap_init_zone(size, nid, zone, start_pfn,
 550                                  MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
 551         } else {
 552                 struct page *start;
 553                 struct memmap_init_callback_data args;
 554
 555                 start = pfn_to_page(start_pfn);
 556                 args.start = start;
 557                 args.end = start + size;
 558                 args.nid = nid;
 559                 args.zone = zone;
 560
 561                 efi_memmap_walk(virtual_memmap_init, &args);
 562         }
 563 }
 564
 565 int
 566 ia64_pfn_valid (unsigned long pfn)
 567 {
 568         char byte;
 569         struct page *pg = pfn_to_page(pfn);
 570
 571         return     (__get_user(byte, (char __user *) pg) == 0)
 572                 && ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
 573                         || (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
 574 }
 575 EXPORT_SYMBOL(ia64_pfn_valid);
 576
 577 #endif /* CONFIG_VIRTUAL_MEM_MAP */
 578
 579 int __init register_active_ranges(u64 start, u64 len, int nid)
 580 {
 581         u64 end = start + len;
 582
 583 #ifdef CONFIG_KEXEC
 584         if (start > crashk_res.start && start < crashk_res.end)
 585                 start = crashk_res.end;
 586         if (end > crashk_res.start && end < crashk_res.end)
 587                 end = crashk_res.start;
 588 #endif
 589
 590         if (start < end)
 591                 memblock_add_node(__pa(start), end - start, nid);
 592         return 0;
 593 }
 594
 595 int
 596 find_max_min_low_pfn (u64 start, u64 end, void *arg)
 597 {
 598         unsigned long pfn_start, pfn_end;
 599 #ifdef CONFIG_FLATMEM
 600         pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
 601         pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
 602 #else
 603         pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
 604         pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
 605 #endif
 606         min_low_pfn = min(min_low_pfn, pfn_start);
 607         max_low_pfn = max(max_low_pfn, pfn_end);
 608         return 0;
 609 }
 610
 611 /*
 612  * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
 613  * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
 614  * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
 615  * useful for performance testing, but conceivably could also come in handy for debugging
 616  * purposes.
 617  */
 618
 619 static int nolwsys __initdata;
 620
 621 static int __init
 622 nolwsys_setup (char *s)
 623 {
 624         nolwsys = 1;
 625         return 1;
 626 }
 627
 628 __setup("nolwsys", nolwsys_setup);
 629
 630 void __init
 631 mem_init (void)
 632 {
 633         int i;
 634
 635         BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
 636         BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
 637         BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
 638
 639         /*
 640          * This needs to be called _after_ the command line has been parsed but
 641          * _before_ any drivers that may need the PCI DMA interface are
 642          * initialized or bootmem has been freed.
 643          */
 644 #ifdef CONFIG_INTEL_IOMMU
 645         detect_intel_iommu();
 646         if (!iommu_detected)
 647 #endif
 648 #ifdef CONFIG_SWIOTLB
 649                 swiotlb_init(1);
 650 #endif
 651
 652 #ifdef CONFIG_FLATMEM
 653         BUG_ON(!mem_map);
 654 #endif
 655
 656         set_max_mapnr(max_low_pfn);
 657         high_memory = __va(max_low_pfn * PAGE_SIZE);
 658         memblock_free_all();
 659         mem_init_print_info(NULL);
 660
 661         /*
 662          * For fsyscall entrpoints with no light-weight handler, use the ordinary
 663          * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
 664          * code can tell them apart.
 665          */
 666         for (i = 0; i < NR_syscalls; ++i) {
 667                 extern unsigned long fsyscall_table[NR_syscalls];
 668                 extern unsigned long sys_call_table[NR_syscalls];
 669
 670                 if (!fsyscall_table[i] || nolwsys)
 671                         fsyscall_table[i] = sys_call_table[i] | 1;
 672         }
 673         setup_gate();
 674 }
 675
 676 #ifdef CONFIG_MEMORY_HOTPLUG
 677 int arch_add_memory(int nid, u64 start, u64 size,
 678                     struct mhp_params *params)
 679 {
 680         unsigned long start_pfn = start >> PAGE_SHIFT;
 681         unsigned long nr_pages = size >> PAGE_SHIFT;
 682         int ret;
 683
 684         if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot))
 685                 return -EINVAL;
 686
 687         ret = __add_pages(nid, start_pfn, nr_pages, params);
 688         if (ret)
 689                 printk("%s: Problem encountered in __add_pages() as ret=%d\n",
 690                        __func__,  ret);
 691
 692         return ret;
 693 }
 694
 695 void arch_remove_memory(int nid, u64 start, u64 size,
 696                         struct vmem_altmap *altmap)
 697 {
 698         unsigned long start_pfn = start >> PAGE_SHIFT;
 699         unsigned long nr_pages = size >> PAGE_SHIFT;
 700
 701         __remove_pages(start_pfn, nr_pages, altmap);
 702 }
 703 #endif