arch/ia64/mm/init.c

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This source file includes following definitions.
__ia64_sync_icache_dcache
arch_sync_dma_for_cpu
ia64_set_rbs_bot
ia64_init_addr_space
free_initmem
free_initrd_mem
put_kernel_page
setup_gate
gate_vma_init
get_gate_vma
in_gate_area_no_mm
in_gate_area
ia64_mmu_init
vmemmap_find_next_valid_pfn
create_mem_map_page_table
virtual_memmap_init
memmap_init
ia64_pfn_valid
find_largest_hole
register_active_ranges
find_max_min_low_pfn
nolwsys_setup
mem_init
arch_add_memory
arch_remove_memory
   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 
  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_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 
  86 inline void
  87 ia64_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  */
 102 void
 103 ia64_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 
 150 void
 151 free_initmem (void)
 152 {
 153         free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
 154                            -1, "unused kernel");
 155 }
 156 
 157 void __init
 158 free_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  */
 207 static struct page * __init
 208 put_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 
 236 static void __init
 237 setup_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 
 271 static struct vm_area_struct gate_vma;
 272 
 273 static 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 
 285 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 286 {
 287         return &gate_vma;
 288 }
 289 
 290 int 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 
 297 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 298 {
 299         return in_gate_area_no_mm(addr);
 300 }
 301 
 302 void 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
 373 int 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);
 408 retry_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 
 427 int __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 
 481 err_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 
 487 struct memmap_init_callback_data {
 488         struct page *start;
 489         struct page *end;
 490         int nid;
 491         unsigned long zone;
 492 };
 493 
 494 static int __meminit
 495 virtual_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 
 525 void __meminit
 526 memmap_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 
 546 int
 547 ia64_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 }
 556 EXPORT_SYMBOL(ia64_pfn_valid);
 557 
 558 int __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 
 574 int __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 
 590 int
 591 find_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 
 614 static int nolwsys __initdata;
 615 
 616 static int __init
 617 nolwsys_setup (char *s)
 618 {
 619         nolwsys = 1;
 620         return 1;
 621 }
 622 
 623 __setup("nolwsys", nolwsys_setup);
 624 
 625 void __init
 626 mem_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
 672 int 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 
 687 void 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 
 693         __remove_pages(start_pfn, nr_pages, altmap);
 694 }
 695 #endif
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root/arch/ia64/mm/init.c

DEFINITIONS
