linux/arch/ia64/mm/init.c
<<
>>
Prefs
   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-noncoherent.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
  41extern void ia64_tlb_init (void);
  42
  43unsigned long MAX_DMA_ADDRESS = PAGE_OFFSET + 0x100000000UL;
  44
  45#ifdef CONFIG_VIRTUAL_MEM_MAP
  46unsigned long VMALLOC_END = VMALLOC_END_INIT;
  47EXPORT_SYMBOL(VMALLOC_END);
  48struct page *vmem_map;
  49EXPORT_SYMBOL(vmem_map);
  50#endif
  51
  52struct page *zero_page_memmap_ptr;      /* map entry for zero page */
  53EXPORT_SYMBOL(zero_page_memmap_ptr);
  54
  55void
  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 */
  76void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
  77                size_t size, enum dma_data_direction dir)
  78{
  79        unsigned long pfn = PHYS_PFN(paddr);
  80
  81        do {
  82                set_bit(PG_arch_1, &pfn_to_page(pfn)->flags);
  83        } while (++pfn <= PHYS_PFN(paddr + size - 1));
  84}
  85
  86inline void
  87ia64_set_rbs_bot (void)
  88{
  89        unsigned long stack_size = rlimit_max(RLIMIT_STACK) & -16;
  90
  91        if (stack_size > MAX_USER_STACK_SIZE)
  92                stack_size = MAX_USER_STACK_SIZE;
  93        current->thread.rbs_bot = PAGE_ALIGN(current->mm->start_stack - stack_size);
  94}
  95
  96/*
  97 * This performs some platform-dependent address space initialization.
  98 * On IA-64, we want to setup the VM area for the register backing
  99 * store (which grows upwards) and install the gateway page which is
 100 * used for signal trampolines, etc.
 101 */
 102void
 103ia64_init_addr_space (void)
 104{
 105        struct vm_area_struct *vma;
 106
 107        ia64_set_rbs_bot();
 108
 109        /*
 110         * If we're out of memory and kmem_cache_alloc() returns NULL, we simply ignore
 111         * the problem.  When the process attempts to write to the register backing store
 112         * for the first time, it will get a SEGFAULT in this case.
 113         */
 114        vma = vm_area_alloc(current->mm);
 115        if (vma) {
 116                vma_set_anonymous(vma);
 117                vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
 118                vma->vm_end = vma->vm_start + PAGE_SIZE;
 119                vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
 120                vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 121                down_write(&current->mm->mmap_sem);
 122                if (insert_vm_struct(current->mm, vma)) {
 123                        up_write(&current->mm->mmap_sem);
 124                        vm_area_free(vma);
 125                        return;
 126                }
 127                up_write(&current->mm->mmap_sem);
 128        }
 129
 130        /* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
 131        if (!(current->personality & MMAP_PAGE_ZERO)) {
 132                vma = vm_area_alloc(current->mm);
 133                if (vma) {
 134                        vma_set_anonymous(vma);
 135                        vma->vm_end = PAGE_SIZE;
 136                        vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
 137                        vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
 138                                        VM_DONTEXPAND | VM_DONTDUMP;
 139                        down_write(&current->mm->mmap_sem);
 140                        if (insert_vm_struct(current->mm, vma)) {
 141                                up_write(&current->mm->mmap_sem);
 142                                vm_area_free(vma);
 143                                return;
 144                        }
 145                        up_write(&current->mm->mmap_sem);
 146                }
 147        }
 148}
 149
 150void
 151free_initmem (void)
 152{
 153        free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
 154                           -1, "unused kernel");
 155}
 156
 157void __init
 158free_initrd_mem (unsigned long start, unsigned long end)
 159{
 160        /*
 161         * EFI uses 4KB pages while the kernel can use 4KB or bigger.
 162         * Thus EFI and the kernel may have different page sizes. It is
 163         * therefore possible to have the initrd share the same page as
 164         * the end of the kernel (given current setup).
 165         *
 166         * To avoid freeing/using the wrong page (kernel sized) we:
 167         *      - align up the beginning of initrd
 168         *      - align down the end of initrd
 169         *
 170         *  |             |
 171         *  |=============| a000
 172         *  |             |
 173         *  |             |
 174         *  |             | 9000
 175         *  |/////////////|
 176         *  |/////////////|
 177         *  |=============| 8000
 178         *  |///INITRD////|
 179         *  |/////////////|
 180         *  |/////////////| 7000
 181         *  |             |
 182         *  |KKKKKKKKKKKKK|
 183         *  |=============| 6000
 184         *  |KKKKKKKKKKKKK|
 185         *  |KKKKKKKKKKKKK|
 186         *  K=kernel using 8KB pages
 187         *
 188         * In this example, we must free page 8000 ONLY. So we must align up
 189         * initrd_start and keep initrd_end as is.
 190         */
 191        start = PAGE_ALIGN(start);
 192        end = end & PAGE_MASK;
 193
 194        if (start < end)
 195                printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);
 196
 197        for (; start < end; start += PAGE_SIZE) {
 198                if (!virt_addr_valid(start))
 199                        continue;
 200                free_reserved_page(virt_to_page(start));
 201        }
 202}
 203
 204/*
 205 * This installs a clean page in the kernel's page table.
 206 */
 207static struct page * __init
 208put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
 209{
 210        pgd_t *pgd;
 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                pud = pud_alloc(&init_mm, pgd, address);
 219                if (!pud)
 220                        goto out;
 221                pmd = pmd_alloc(&init_mm, pud, address);
 222                if (!pmd)
 223                        goto out;
 224                pte = pte_alloc_kernel(pmd, address);
 225                if (!pte)
 226                        goto out;
 227                if (!pte_none(*pte))
 228                        goto out;
 229                set_pte(pte, mk_pte(page, pgprot));
 230        }
 231  out:
 232        /* no need for flush_tlb */
 233        return page;
 234}
 235
 236static void __init
 237setup_gate (void)
 238{
 239        struct page *page;
 240
 241        /*
 242         * Map the gate page twice: once read-only to export the ELF
 243         * headers etc. and once execute-only page to enable
 244         * privilege-promotion via "epc":
 245         */
 246        page = virt_to_page(ia64_imva(__start_gate_section));
 247        put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
 248#ifdef HAVE_BUGGY_SEGREL
 249        page = virt_to_page(ia64_imva(__start_gate_section + PAGE_SIZE));
 250        put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
 251#else
 252        put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
 253        /* Fill in the holes (if any) with read-only zero pages: */
 254        {
 255                unsigned long addr;
 256
 257                for (addr = GATE_ADDR + PAGE_SIZE;
 258                     addr < GATE_ADDR + PERCPU_PAGE_SIZE;
 259                     addr += PAGE_SIZE)
 260                {
 261                        put_kernel_page(ZERO_PAGE(0), addr,
 262                                        PAGE_READONLY);
 263                        put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
 264                                        PAGE_READONLY);
 265                }
 266        }
 267#endif
 268        ia64_patch_gate();
 269}
 270
 271static struct vm_area_struct gate_vma;
 272
 273static int __init gate_vma_init(void)
 274{
 275        vma_init(&gate_vma, NULL);
 276        gate_vma.vm_start = FIXADDR_USER_START;
 277        gate_vma.vm_end = FIXADDR_USER_END;
 278        gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
 279        gate_vma.vm_page_prot = __P101;
 280
 281        return 0;
 282}
 283__initcall(gate_vma_init);
 284
 285struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 286{
 287        return &gate_vma;
 288}
 289
 290int in_gate_area_no_mm(unsigned long addr)
 291{
 292        if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
 293                return 1;
 294        return 0;
 295}
 296
 297int in_gate_area(struct mm_struct *mm, unsigned long addr)
 298{
 299        return in_gate_area_no_mm(addr);
 300}
 301
 302void ia64_mmu_init(void *my_cpu_data)
 303{
 304        unsigned long pta, impl_va_bits;
 305        extern void tlb_init(void);
 306
 307#ifdef CONFIG_DISABLE_VHPT
 308#       define VHPT_ENABLE_BIT  0
 309#else
 310#       define VHPT_ENABLE_BIT  1
 311#endif
 312
 313        /*
 314         * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
 315         * address space.  The IA-64 architecture guarantees that at least 50 bits of
 316         * virtual address space are implemented but if we pick a large enough page size
 317         * (e.g., 64KB), the mapped address space is big enough that it will overlap with
 318         * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
 319         * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
 320         * problem in practice.  Alternatively, we could truncate the top of the mapped
 321         * address space to not permit mappings that would overlap with the VMLPT.
 322         * --davidm 00/12/06
 323         */
 324#       define pte_bits                 3
 325#       define mapped_space_bits        (3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
 326        /*
 327         * The virtual page table has to cover the entire implemented address space within
 328         * a region even though not all of this space may be mappable.  The reason for
 329         * this is that the Access bit and Dirty bit fault handlers perform
 330         * non-speculative accesses to the virtual page table, so the address range of the
 331         * virtual page table itself needs to be covered by virtual page table.
 332         */
 333#       define vmlpt_bits               (impl_va_bits - PAGE_SHIFT + pte_bits)
 334#       define POW2(n)                  (1ULL << (n))
 335
 336        impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));
 337
 338        if (impl_va_bits < 51 || impl_va_bits > 61)
 339                panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
 340        /*
 341         * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
 342         * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
 343         * the test makes sure that our mapped space doesn't overlap the
 344         * unimplemented hole in the middle of the region.
 345         */
 346        if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
 347            (mapped_space_bits > impl_va_bits - 1))
 348                panic("Cannot build a big enough virtual-linear page table"
 349                      " to cover mapped address space.\n"
 350                      " Try using a smaller page size.\n");
 351
 352
 353        /* place the VMLPT at the end of each page-table mapped region: */
 354        pta = POW2(61) - POW2(vmlpt_bits);
 355
 356        /*
 357         * Set the (virtually mapped linear) page table address.  Bit
 358         * 8 selects between the short and long format, bits 2-7 the
 359         * size of the table, and bit 0 whether the VHPT walker is
 360         * enabled.
 361         */
 362        ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);
 363
 364        ia64_tlb_init();
 365
 366#ifdef  CONFIG_HUGETLB_PAGE
 367        ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
 368        ia64_srlz_d();
 369#endif
 370}
 371
 372#ifdef CONFIG_VIRTUAL_MEM_MAP
 373int vmemmap_find_next_valid_pfn(int node, int i)
 374{
 375        unsigned long end_address, hole_next_pfn;
 376        unsigned long stop_address;
 377        pg_data_t *pgdat = NODE_DATA(node);
 378
 379        end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
 380        end_address = PAGE_ALIGN(end_address);
 381        stop_address = (unsigned long) &vmem_map[pgdat_end_pfn(pgdat)];
 382
 383        do {
 384                pgd_t *pgd;
 385                pud_t *pud;
 386                pmd_t *pmd;
 387                pte_t *pte;
 388
 389                pgd = pgd_offset_k(end_address);
 390                if (pgd_none(*pgd)) {
 391                        end_address += PGDIR_SIZE;
 392                        continue;
 393                }
 394
 395                pud = pud_offset(pgd, end_address);
 396                if (pud_none(*pud)) {
 397                        end_address += PUD_SIZE;
 398                        continue;
 399                }
 400
 401                pmd = pmd_offset(pud, end_address);
 402                if (pmd_none(*pmd)) {
 403                        end_address += PMD_SIZE;
 404                        continue;
 405                }
 406
 407                pte = pte_offset_kernel(pmd, end_address);
 408retry_pte:
 409                if (pte_none(*pte)) {
 410                        end_address += PAGE_SIZE;
 411                        pte++;
 412                        if ((end_address < stop_address) &&
 413                            (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
 414                                goto retry_pte;
 415                        continue;
 416                }
 417                /* Found next valid vmem_map page */
 418                break;
 419        } while (end_address < stop_address);
 420
 421        end_address = min(end_address, stop_address);
 422        end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
 423        hole_next_pfn = end_address / sizeof(struct page);
 424        return hole_next_pfn - pgdat->node_start_pfn;
 425}
 426
 427int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
 428{
 429        unsigned long address, start_page, end_page;
 430        struct page *map_start, *map_end;
 431        int node;
 432        pgd_t *pgd;
 433        pud_t *pud;
 434        pmd_t *pmd;
 435        pte_t *pte;
 436
 437        map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
 438        map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
 439
 440        start_page = (unsigned long) map_start & PAGE_MASK;
 441        end_page = PAGE_ALIGN((unsigned long) map_end);
 442        node = paddr_to_nid(__pa(start));
 443
 444        for (address = start_page; address < end_page; address += PAGE_SIZE) {
 445                pgd = pgd_offset_k(address);
 446                if (pgd_none(*pgd)) {
 447                        pud = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
 448                        if (!pud)
 449                                goto err_alloc;
 450                        pgd_populate(&init_mm, pgd, pud);
 451                }
 452                pud = pud_offset(pgd, address);
 453
 454                if (pud_none(*pud)) {
 455                        pmd = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
 456                        if (!pmd)
 457                                goto err_alloc;
 458                        pud_populate(&init_mm, pud, pmd);
 459                }
 460                pmd = pmd_offset(pud, address);
 461
 462                if (pmd_none(*pmd)) {
 463                        pte = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
 464                        if (!pte)
 465                                goto err_alloc;
 466                        pmd_populate_kernel(&init_mm, pmd, pte);
 467                }
 468                pte = pte_offset_kernel(pmd, address);
 469
 470                if (pte_none(*pte)) {
 471                        void *page = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE,
 472                                                         node);
 473                        if (!page)
 474                                goto err_alloc;
 475                        set_pte(pte, pfn_pte(__pa(page) >> PAGE_SHIFT,
 476                                             PAGE_KERNEL));
 477                }
 478        }
 479        return 0;
 480
 481err_alloc:
 482        panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d\n",
 483              __func__, PAGE_SIZE, PAGE_SIZE, node);
 484        return -ENOMEM;
 485}
 486
 487struct memmap_init_callback_data {
 488        struct page *start;
 489        struct page *end;
 490        int nid;
 491        unsigned long zone;
 492};
 493
 494static int __meminit
 495virtual_memmap_init(u64 start, u64 end, void *arg)
 496{
 497        struct memmap_init_callback_data *args;
 498        struct page *map_start, *map_end;
 499
 500        args = (struct memmap_init_callback_data *) arg;
 501        map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
 502        map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
 503
 504        if (map_start < args->start)
 505                map_start = args->start;
 506        if (map_end > args->end)
 507                map_end = args->end;
 508
 509        /*
 510         * We have to initialize "out of bounds" struct page elements that fit completely
 511         * on the same pages that were allocated for the "in bounds" elements because they
 512         * may be referenced later (and found to be "reserved").
 513         */
 514        map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
 515        map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
 516                    / sizeof(struct page));
 517
 518        if (map_start < map_end)
 519                memmap_init_zone((unsigned long)(map_end - map_start),
 520                                 args->nid, args->zone, page_to_pfn(map_start),
 521                                 MEMMAP_EARLY, NULL);
 522        return 0;
 523}
 524
 525void __meminit
 526memmap_init (unsigned long size, int nid, unsigned long zone,
 527             unsigned long start_pfn)
 528{
 529        if (!vmem_map) {
 530                memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY,
 531                                NULL);
 532        } else {
 533                struct page *start;
 534                struct memmap_init_callback_data args;
 535
 536                start = pfn_to_page(start_pfn);
 537                args.start = start;
 538                args.end = start + size;
 539                args.nid = nid;
 540                args.zone = zone;
 541
 542                efi_memmap_walk(virtual_memmap_init, &args);
 543        }
 544}
 545
 546int
 547ia64_pfn_valid (unsigned long pfn)
 548{
 549        char byte;
 550        struct page *pg = pfn_to_page(pfn);
 551
 552        return     (__get_user(byte, (char __user *) pg) == 0)
 553                && ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
 554                        || (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
 555}
 556EXPORT_SYMBOL(ia64_pfn_valid);
 557
 558int __init find_largest_hole(u64 start, u64 end, void *arg)
 559{
 560        u64 *max_gap = arg;
 561
 562        static u64 last_end = PAGE_OFFSET;
 563
 564        /* NOTE: this algorithm assumes efi memmap table is ordered */
 565
 566        if (*max_gap < (start - last_end))
 567                *max_gap = start - last_end;
 568        last_end = end;
 569        return 0;
 570}
 571
 572#endif /* CONFIG_VIRTUAL_MEM_MAP */
 573
 574int __init register_active_ranges(u64 start, u64 len, int nid)
 575{
 576        u64 end = start + len;
 577
 578#ifdef CONFIG_KEXEC
 579        if (start > crashk_res.start && start < crashk_res.end)
 580                start = crashk_res.end;
 581        if (end > crashk_res.start && end < crashk_res.end)
 582                end = crashk_res.start;
 583#endif
 584
 585        if (start < end)
 586                memblock_add_node(__pa(start), end - start, nid);
 587        return 0;
 588}
 589
 590int
 591find_max_min_low_pfn (u64 start, u64 end, void *arg)
 592{
 593        unsigned long pfn_start, pfn_end;
 594#ifdef CONFIG_FLATMEM
 595        pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
 596        pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
 597#else
 598        pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
 599        pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
 600#endif
 601        min_low_pfn = min(min_low_pfn, pfn_start);
 602        max_low_pfn = max(max_low_pfn, pfn_end);
 603        return 0;
 604}
 605
 606/*
 607 * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
 608 * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
 609 * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
 610 * useful for performance testing, but conceivably could also come in handy for debugging
 611 * purposes.
 612 */
 613
 614static int nolwsys __initdata;
 615
 616static int __init
 617nolwsys_setup (char *s)
 618{
 619        nolwsys = 1;
 620        return 1;
 621}
 622
 623__setup("nolwsys", nolwsys_setup);
 624
 625void __init
 626mem_init (void)
 627{
 628        int i;
 629
 630        BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
 631        BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
 632        BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
 633
 634        /*
 635         * This needs to be called _after_ the command line has been parsed but
 636         * _before_ any drivers that may need the PCI DMA interface are
 637         * initialized or bootmem has been freed.
 638         */
 639#ifdef CONFIG_INTEL_IOMMU
 640        detect_intel_iommu();
 641        if (!iommu_detected)
 642#endif
 643#ifdef CONFIG_SWIOTLB
 644                swiotlb_init(1);
 645#endif
 646
 647#ifdef CONFIG_FLATMEM
 648        BUG_ON(!mem_map);
 649#endif
 650
 651        set_max_mapnr(max_low_pfn);
 652        high_memory = __va(max_low_pfn * PAGE_SIZE);
 653        memblock_free_all();
 654        mem_init_print_info(NULL);
 655
 656        /*
 657         * For fsyscall entrpoints with no light-weight handler, use the ordinary
 658         * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
 659         * code can tell them apart.
 660         */
 661        for (i = 0; i < NR_syscalls; ++i) {
 662                extern unsigned long fsyscall_table[NR_syscalls];
 663                extern unsigned long sys_call_table[NR_syscalls];
 664
 665                if (!fsyscall_table[i] || nolwsys)
 666                        fsyscall_table[i] = sys_call_table[i] | 1;
 667        }
 668        setup_gate();
 669}
 670
 671#ifdef CONFIG_MEMORY_HOTPLUG
 672int arch_add_memory(int nid, u64 start, u64 size,
 673                        struct mhp_restrictions *restrictions)
 674{
 675        unsigned long start_pfn = start >> PAGE_SHIFT;
 676        unsigned long nr_pages = size >> PAGE_SHIFT;
 677        int ret;
 678
 679        ret = __add_pages(nid, start_pfn, nr_pages, restrictions);
 680        if (ret)
 681                printk("%s: Problem encountered in __add_pages() as ret=%d\n",
 682                       __func__,  ret);
 683
 684        return ret;
 685}
 686
 687void arch_remove_memory(int nid, u64 start, u64 size,
 688                        struct vmem_altmap *altmap)
 689{
 690        unsigned long start_pfn = start >> PAGE_SHIFT;
 691        unsigned long nr_pages = size >> PAGE_SHIFT;
 692        struct zone *zone;
 693
 694        zone = page_zone(pfn_to_page(start_pfn));
 695        __remove_pages(zone, start_pfn, nr_pages, altmap);
 696}
 697#endif
 698