1 /* 2 * Initialize MMU support. 3 * 4 * Copyright (C) 1998-2003 Hewlett-Packard Co 5 * David Mosberger-Tang <davidm@hpl.hp.com> 6 */ 7 #include <linux/kernel.h> 8 #include <linux/init.h> 9 10 #include <linux/bootmem.h> 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 = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); 117 if (vma) { 118 INIT_LIST_HEAD(&vma->anon_vma_chain); 119 vma->vm_mm = current->mm; 120 vma->vm_start = current->thread.rbs_bot & PAGE_MASK; 121 vma->vm_end = vma->vm_start + PAGE_SIZE; 122 vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT; 123 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 124 down_write(¤t->mm->mmap_sem); 125 if (insert_vm_struct(current->mm, vma)) { 126 up_write(¤t->mm->mmap_sem); 127 kmem_cache_free(vm_area_cachep, vma); 128 return; 129 } 130 up_write(¤t->mm->mmap_sem); 131 } 132 133 /* map NaT-page at address zero to speed up speculative dereferencing of NULL: */ 134 if (!(current->personality & MMAP_PAGE_ZERO)) { 135 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); 136 if (vma) { 137 INIT_LIST_HEAD(&vma->anon_vma_chain); 138 vma->vm_mm = current->mm; 139 vma->vm_end = PAGE_SIZE; 140 vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT); 141 vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO | 142 VM_DONTEXPAND | VM_DONTDUMP; 143 down_write(¤t->mm->mmap_sem); 144 if (insert_vm_struct(current->mm, vma)) { 145 up_write(¤t->mm->mmap_sem); 146 kmem_cache_free(vm_area_cachep, vma); 147 return; 148 } 149 up_write(¤t->mm->mmap_sem); 150 } 151 } 152 } 153 154 void 155 free_initmem (void) 156 { 157 free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end), 158 -1, "unused kernel"); 159 } 160 161 void __init 162 free_initrd_mem (unsigned long start, unsigned long end) 163 { 164 /* 165 * EFI uses 4KB pages while the kernel can use 4KB or bigger. 166 * Thus EFI and the kernel may have different page sizes. It is 167 * therefore possible to have the initrd share the same page as 168 * the end of the kernel (given current setup). 169 * 170 * To avoid freeing/using the wrong page (kernel sized) we: 171 * - align up the beginning of initrd 172 * - align down the end of initrd 173 * 174 * | | 175 * |=============| a000 176 * | | 177 * | | 178 * | | 9000 179 * |/////////////| 180 * |/////////////| 181 * |=============| 8000 182 * |///INITRD////| 183 * |/////////////| 184 * |/////////////| 7000 185 * | | 186 * |KKKKKKKKKKKKK| 187 * |=============| 6000 188 * |KKKKKKKKKKKKK| 189 * |KKKKKKKKKKKKK| 190 * K=kernel using 8KB pages 191 * 192 * In this example, we must free page 8000 ONLY. So we must align up 193 * initrd_start and keep initrd_end as is. 194 */ 195 start = PAGE_ALIGN(start); 196 end = end & PAGE_MASK; 197 198 if (start < end) 199 printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10); 200 201 for (; start < end; start += PAGE_SIZE) { 202 if (!virt_addr_valid(start)) 203 continue; 204 free_reserved_page(virt_to_page(start)); 205 } 206 } 207 208 /* 209 * This installs a clean page in the kernel's page table. 210 */ 211 static struct page * __init 212 put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot) 213 { 214 pgd_t *pgd; 215 pud_t *pud; 216 pmd_t *pmd; 217 pte_t *pte; 218 219 pgd = pgd_offset_k(address); /* note: this is NOT pgd_offset()! */ 220 221 { 222 pud = pud_alloc(&init_mm, pgd, address); 223 if (!pud) 224 goto out; 225 pmd = pmd_alloc(&init_mm, pud, address); 226 if (!pmd) 227 goto out; 228 pte = pte_alloc_kernel(pmd, address); 229 if (!pte) 230 goto out; 231 if (!pte_none(*pte)) 232 goto out; 233 set_pte(pte, mk_pte(page, pgprot)); 234 } 235 out: 236 /* no need for flush_tlb */ 237 return page; 238 } 239 240 static void __init 241 setup_gate (void) 242 { 243 struct page *page; 244 245 /* 246 * Map the gate page twice: once read-only to export the ELF 247 * headers etc. and once execute-only page to enable 248 * privilege-promotion via "epc": 249 */ 250 page = virt_to_page(ia64_imva(__start_gate_section)); 251 put_kernel_page(page, GATE_ADDR, PAGE_READONLY); 252 #ifdef HAVE_BUGGY_SEGREL 253 page = virt_to_page(ia64_imva(__start_gate_section + PAGE_SIZE)); 254 put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE); 255 #else 256 put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE); 257 /* Fill in the holes (if any) with read-only zero pages: */ 258 { 259 unsigned long addr; 260 261 for (addr = GATE_ADDR + PAGE_SIZE; 262 addr < GATE_ADDR + PERCPU_PAGE_SIZE; 263 addr += PAGE_SIZE) 264 { 265 put_kernel_page(ZERO_PAGE(0), addr, 266 PAGE_READONLY); 267 put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE, 268 PAGE_READONLY); 269 } 270 } 271 #endif 272 ia64_patch_gate(); 273 } 274 275 static struct vm_area_struct gate_vma; 276 277 static int __init gate_vma_init(void) 278 { 279 gate_vma.vm_mm = NULL; 280 gate_vma.vm_start = FIXADDR_USER_START; 281 gate_vma.vm_end = FIXADDR_USER_END; 282 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; 283 gate_vma.vm_page_prot = __P101; 284 285 return 0; 286 } 287 __initcall(gate_vma_init); 288 289 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 290 { 291 return &gate_vma; 292 } 293 294 int in_gate_area_no_mm(unsigned long addr) 295 { 296 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) 297 return 1; 298 return 0; 299 } 300 301 int in_gate_area(struct mm_struct *mm, unsigned long addr) 302 { 303 return in_gate_area_no_mm(addr); 304 } 305 306 void ia64_mmu_init(void *my_cpu_data) 307 { 308 unsigned long pta, impl_va_bits; 309 extern void tlb_init(void); 310 311 #ifdef CONFIG_DISABLE_VHPT 312 # define VHPT_ENABLE_BIT 0 313 #else 314 # define VHPT_ENABLE_BIT 1 315 #endif 316 317 /* 318 * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped 319 * address space. The IA-64 architecture guarantees that at least 50 bits of 320 * virtual address space are implemented but if we pick a large enough page size 321 * (e.g., 64KB), the mapped address space is big enough that it will overlap with 322 * VMLPT. I assume that once we run on machines big enough to warrant 64KB pages, 323 * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a 324 * problem in practice. Alternatively, we could truncate the top of the mapped 325 * address space to not permit mappings that would overlap with the VMLPT. 326 * --davidm 00/12/06 327 */ 328 # define pte_bits 3 329 # define mapped_space_bits (3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT) 330 /* 331 * The virtual page table has to cover the entire implemented address space within 332 * a region even though not all of this space may be mappable. The reason for 333 * this is that the Access bit and Dirty bit fault handlers perform 334 * non-speculative accesses to the virtual page table, so the address range of the 335 * virtual page table itself needs to be covered by virtual page table. 336 */ 337 # define vmlpt_bits (impl_va_bits - PAGE_SHIFT + pte_bits) 338 # define POW2(n) (1ULL << (n)) 339 340 impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61))); 341 342 if (impl_va_bits < 51 || impl_va_bits > 61) 343 panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1); 344 /* 345 * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need, 346 * which must fit into "vmlpt_bits - pte_bits" slots. Second half of 347 * the test makes sure that our mapped space doesn't overlap the 348 * unimplemented hole in the middle of the region. 349 */ 350 if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) || 351 (mapped_space_bits > impl_va_bits - 1)) 352 panic("Cannot build a big enough virtual-linear page table" 353 " to cover mapped address space.\n" 354 " Try using a smaller page size.\n"); 355 356 357 /* place the VMLPT at the end of each page-table mapped region: */ 358 pta = POW2(61) - POW2(vmlpt_bits); 359 360 /* 361 * Set the (virtually mapped linear) page table address. Bit 362 * 8 selects between the short and long format, bits 2-7 the 363 * size of the table, and bit 0 whether the VHPT walker is 364 * enabled. 365 */ 366 ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT); 367 368 ia64_tlb_init(); 369 370 #ifdef CONFIG_HUGETLB_PAGE 371 ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2); 372 ia64_srlz_d(); 373 #endif 374 } 375 376 #ifdef CONFIG_VIRTUAL_MEM_MAP 377 int vmemmap_find_next_valid_pfn(int node, int i) 378 { 379 unsigned long end_address, hole_next_pfn; 380 unsigned long stop_address; 381 pg_data_t *pgdat = NODE_DATA(node); 382 383 end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i]; 384 end_address = PAGE_ALIGN(end_address); 385 stop_address = (unsigned long) &vmem_map[pgdat_end_pfn(pgdat)]; 386 387 do { 388 pgd_t *pgd; 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 pud = pud_offset(pgd, end_address); 400 if (pud_none(*pud)) { 401 end_address += PUD_SIZE; 402 continue; 403 } 404 405 pmd = pmd_offset(pud, end_address); 406 if (pmd_none(*pmd)) { 407 end_address += PMD_SIZE; 408 continue; 409 } 410 411 pte = pte_offset_kernel(pmd, end_address); 412 retry_pte: 413 if (pte_none(*pte)) { 414 end_address += PAGE_SIZE; 415 pte++; 416 if ((end_address < stop_address) && 417 (end_address != ALIGN(end_address, 1UL << PMD_SHIFT))) 418 goto retry_pte; 419 continue; 420 } 421 /* Found next valid vmem_map page */ 422 break; 423 } while (end_address < stop_address); 424 425 end_address = min(end_address, stop_address); 426 end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1; 427 hole_next_pfn = end_address / sizeof(struct page); 428 return hole_next_pfn - pgdat->node_start_pfn; 429 } 430 431 int __init create_mem_map_page_table(u64 start, u64 end, void *arg) 432 { 433 unsigned long address, start_page, end_page; 434 struct page *map_start, *map_end; 435 int node; 436 pgd_t *pgd; 437 pud_t *pud; 438 pmd_t *pmd; 439 pte_t *pte; 440 441 map_start = vmem_map + (__pa(start) >> PAGE_SHIFT); 442 map_end = vmem_map + (__pa(end) >> PAGE_SHIFT); 443 444 start_page = (unsigned long) map_start & PAGE_MASK; 445 end_page = PAGE_ALIGN((unsigned long) map_end); 446 node = paddr_to_nid(__pa(start)); 447 448 for (address = start_page; address < end_page; address += PAGE_SIZE) { 449 pgd = pgd_offset_k(address); 450 if (pgd_none(*pgd)) 451 pgd_populate(&init_mm, pgd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE)); 452 pud = pud_offset(pgd, address); 453 454 if (pud_none(*pud)) 455 pud_populate(&init_mm, pud, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE)); 456 pmd = pmd_offset(pud, address); 457 458 if (pmd_none(*pmd)) 459 pmd_populate_kernel(&init_mm, pmd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE)); 460 pte = pte_offset_kernel(pmd, address); 461 462 if (pte_none(*pte)) 463 set_pte(pte, pfn_pte(__pa(alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE)) >> PAGE_SHIFT, 464 PAGE_KERNEL)); 465 } 466 return 0; 467 } 468 469 struct memmap_init_callback_data { 470 struct page *start; 471 struct page *end; 472 int nid; 473 unsigned long zone; 474 }; 475 476 static int __meminit 477 virtual_memmap_init(u64 start, u64 end, void *arg) 478 { 479 struct memmap_init_callback_data *args; 480 struct page *map_start, *map_end; 481 482 args = (struct memmap_init_callback_data *) arg; 483 map_start = vmem_map + (__pa(start) >> PAGE_SHIFT); 484 map_end = vmem_map + (__pa(end) >> PAGE_SHIFT); 485 486 if (map_start < args->start) 487 map_start = args->start; 488 if (map_end > args->end) 489 map_end = args->end; 490 491 /* 492 * We have to initialize "out of bounds" struct page elements that fit completely 493 * on the same pages that were allocated for the "in bounds" elements because they 494 * may be referenced later (and found to be "reserved"). 495 */ 496 map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page); 497 map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end) 498 / sizeof(struct page)); 499 500 if (map_start < map_end) 501 memmap_init_zone((unsigned long)(map_end - map_start), 502 args->nid, args->zone, page_to_pfn(map_start), 503 MEMMAP_EARLY); 504 return 0; 505 } 506 507 void __meminit 508 memmap_init (unsigned long size, int nid, unsigned long zone, 509 unsigned long start_pfn) 510 { 511 if (!vmem_map) 512 memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY); 513 else { 514 struct page *start; 515 struct memmap_init_callback_data args; 516 517 start = pfn_to_page(start_pfn); 518 args.start = start; 519 args.end = start + size; 520 args.nid = nid; 521 args.zone = zone; 522 523 efi_memmap_walk(virtual_memmap_init, &args); 524 } 525 } 526 527 int 528 ia64_pfn_valid (unsigned long pfn) 529 { 530 char byte; 531 struct page *pg = pfn_to_page(pfn); 532 533 return (__get_user(byte, (char __user *) pg) == 0) 534 && ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK)) 535 || (__get_user(byte, (char __user *) (pg + 1) - 1) == 0)); 536 } 537 EXPORT_SYMBOL(ia64_pfn_valid); 538 539 int __init find_largest_hole(u64 start, u64 end, void *arg) 540 { 541 u64 *max_gap = arg; 542 543 static u64 last_end = PAGE_OFFSET; 544 545 /* NOTE: this algorithm assumes efi memmap table is ordered */ 546 547 if (*max_gap < (start - last_end)) 548 *max_gap = start - last_end; 549 last_end = end; 550 return 0; 551 } 552 553 #endif /* CONFIG_VIRTUAL_MEM_MAP */ 554 555 int __init register_active_ranges(u64 start, u64 len, int nid) 556 { 557 u64 end = start + len; 558 559 #ifdef CONFIG_KEXEC 560 if (start > crashk_res.start && start < crashk_res.end) 561 start = crashk_res.end; 562 if (end > crashk_res.start && end < crashk_res.end) 563 end = crashk_res.start; 564 #endif 565 566 if (start < end) 567 memblock_add_node(__pa(start), end - start, nid); 568 return 0; 569 } 570 571 int 572 find_max_min_low_pfn (u64 start, u64 end, void *arg) 573 { 574 unsigned long pfn_start, pfn_end; 575 #ifdef CONFIG_FLATMEM 576 pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT; 577 pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT; 578 #else 579 pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT; 580 pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT; 581 #endif 582 min_low_pfn = min(min_low_pfn, pfn_start); 583 max_low_pfn = max(max_low_pfn, pfn_end); 584 return 0; 585 } 586 587 /* 588 * Boot command-line option "nolwsys" can be used to disable the use of any light-weight 589 * system call handler. When this option is in effect, all fsyscalls will end up bubbling 590 * down into the kernel and calling the normal (heavy-weight) syscall handler. This is 591 * useful for performance testing, but conceivably could also come in handy for debugging 592 * purposes. 593 */ 594 595 static int nolwsys __initdata; 596 597 static int __init 598 nolwsys_setup (char *s) 599 { 600 nolwsys = 1; 601 return 1; 602 } 603 604 __setup("nolwsys", nolwsys_setup); 605 606 void __init 607 mem_init (void) 608 { 609 int i; 610 611 BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE); 612 BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE); 613 BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE); 614 615 #ifdef CONFIG_PCI 616 /* 617 * This needs to be called _after_ the command line has been parsed but _before_ 618 * any drivers that may need the PCI DMA interface are initialized or bootmem has 619 * been freed. 620 */ 621 platform_dma_init(); 622 #endif 623 624 #ifdef CONFIG_FLATMEM 625 BUG_ON(!mem_map); 626 #endif 627 628 set_max_mapnr(max_low_pfn); 629 high_memory = __va(max_low_pfn * PAGE_SIZE); 630 free_all_bootmem(); 631 mem_init_print_info(NULL); 632 633 /* 634 * For fsyscall entrpoints with no light-weight handler, use the ordinary 635 * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry 636 * code can tell them apart. 637 */ 638 for (i = 0; i < NR_syscalls; ++i) { 639 extern unsigned long fsyscall_table[NR_syscalls]; 640 extern unsigned long sys_call_table[NR_syscalls]; 641 642 if (!fsyscall_table[i] || nolwsys) 643 fsyscall_table[i] = sys_call_table[i] | 1; 644 } 645 setup_gate(); 646 } 647 648 #ifdef CONFIG_MEMORY_HOTPLUG 649 int arch_add_memory(int nid, u64 start, u64 size, bool for_device) 650 { 651 pg_data_t *pgdat; 652 struct zone *zone; 653 unsigned long start_pfn = start >> PAGE_SHIFT; 654 unsigned long nr_pages = size >> PAGE_SHIFT; 655 int ret; 656 657 pgdat = NODE_DATA(nid); 658 659 zone = pgdat->node_zones + 660 zone_for_memory(nid, start, size, ZONE_NORMAL, for_device); 661 ret = __add_pages(nid, zone, start_pfn, nr_pages); 662 663 if (ret) 664 printk("%s: Problem encountered in __add_pages() as ret=%d\n", 665 __func__, ret); 666 667 return ret; 668 } 669 670 #ifdef CONFIG_MEMORY_HOTREMOVE 671 int arch_remove_memory(u64 start, u64 size) 672 { 673 unsigned long start_pfn = start >> PAGE_SHIFT; 674 unsigned long nr_pages = size >> PAGE_SHIFT; 675 struct zone *zone; 676 int ret; 677 678 zone = page_zone(pfn_to_page(start_pfn)); 679 ret = __remove_pages(zone, start_pfn, nr_pages); 680 if (ret) 681 pr_warn("%s: Problem encountered in __remove_pages() as" 682 " ret=%d\n", __func__, ret); 683 684 return ret; 685 } 686 #endif 687 #endif 688