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