xref: /openbmc/linux/arch/ia64/mm/init.c (revision 8bd1369b)
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/bootmem.h>
12 #include <linux/efi.h>
13 #include <linux/elf.h>
14 #include <linux/memblock.h>
15 #include <linux/mm.h>
16 #include <linux/sched/signal.h>
17 #include <linux/mmzone.h>
18 #include <linux/module.h>
19 #include <linux/personality.h>
20 #include <linux/reboot.h>
21 #include <linux/slab.h>
22 #include <linux/swap.h>
23 #include <linux/proc_fs.h>
24 #include <linux/bitops.h>
25 #include <linux/kexec.h>
26 
27 #include <asm/dma.h>
28 #include <asm/io.h>
29 #include <asm/machvec.h>
30 #include <asm/numa.h>
31 #include <asm/patch.h>
32 #include <asm/pgalloc.h>
33 #include <asm/sal.h>
34 #include <asm/sections.h>
35 #include <asm/tlb.h>
36 #include <linux/uaccess.h>
37 #include <asm/unistd.h>
38 #include <asm/mca.h>
39 
40 extern void ia64_tlb_init (void);
41 
42 unsigned long MAX_DMA_ADDRESS = PAGE_OFFSET + 0x100000000UL;
43 
44 #ifdef CONFIG_VIRTUAL_MEM_MAP
45 unsigned long VMALLOC_END = VMALLOC_END_INIT;
46 EXPORT_SYMBOL(VMALLOC_END);
47 struct page *vmem_map;
48 EXPORT_SYMBOL(vmem_map);
49 #endif
50 
51 struct page *zero_page_memmap_ptr;	/* map entry for zero page */
52 EXPORT_SYMBOL(zero_page_memmap_ptr);
53 
54 void
55 __ia64_sync_icache_dcache (pte_t pte)
56 {
57 	unsigned long addr;
58 	struct page *page;
59 
60 	page = pte_page(pte);
61 	addr = (unsigned long) page_address(page);
62 
63 	if (test_bit(PG_arch_1, &page->flags))
64 		return;				/* i-cache is already coherent with d-cache */
65 
66 	flush_icache_range(addr, addr + (PAGE_SIZE << compound_order(page)));
67 	set_bit(PG_arch_1, &page->flags);	/* mark page as clean */
68 }
69 
70 /*
71  * Since DMA is i-cache coherent, any (complete) pages that were written via
72  * DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to
73  * flush them when they get mapped into an executable vm-area.
74  */
75 void
76 dma_mark_clean(void *addr, size_t size)
77 {
78 	unsigned long pg_addr, end;
79 
80 	pg_addr = PAGE_ALIGN((unsigned long) addr);
81 	end = (unsigned long) addr + size;
82 	while (pg_addr + PAGE_SIZE <= end) {
83 		struct page *page = virt_to_page(pg_addr);
84 		set_bit(PG_arch_1, &page->flags);
85 		pg_addr += PAGE_SIZE;
86 	}
87 }
88 
89 inline void
90 ia64_set_rbs_bot (void)
91 {
92 	unsigned long stack_size = rlimit_max(RLIMIT_STACK) & -16;
93 
94 	if (stack_size > MAX_USER_STACK_SIZE)
95 		stack_size = MAX_USER_STACK_SIZE;
96 	current->thread.rbs_bot = PAGE_ALIGN(current->mm->start_stack - stack_size);
97 }
98 
99 /*
100  * This performs some platform-dependent address space initialization.
101  * On IA-64, we want to setup the VM area for the register backing
102  * store (which grows upwards) and install the gateway page which is
103  * used for signal trampolines, etc.
104  */
105 void
106 ia64_init_addr_space (void)
107 {
108 	struct vm_area_struct *vma;
109 
110 	ia64_set_rbs_bot();
111 
112 	/*
113 	 * If we're out of memory and kmem_cache_alloc() returns NULL, we simply ignore
114 	 * the problem.  When the process attempts to write to the register backing store
115 	 * for the first time, it will get a SEGFAULT in this case.
116 	 */
117 	vma = vm_area_alloc(current->mm);
118 	if (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->vm_end = PAGE_SIZE;
137 			vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
138 			vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
139 					VM_DONTEXPAND | VM_DONTDUMP;
140 			down_write(&current->mm->mmap_sem);
141 			if (insert_vm_struct(current->mm, vma)) {
142 				up_write(&current->mm->mmap_sem);
143 				vm_area_free(vma);
144 				return;
145 			}
146 			up_write(&current->mm->mmap_sem);
147 		}
148 	}
149 }
150 
151 void
152 free_initmem (void)
153 {
154 	free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
155 			   -1, "unused kernel");
156 }
157 
158 void __init
159 free_initrd_mem (unsigned long start, unsigned long end)
160 {
161 	/*
162 	 * EFI uses 4KB pages while the kernel can use 4KB or bigger.
163 	 * Thus EFI and the kernel may have different page sizes. It is
164 	 * therefore possible to have the initrd share the same page as
165 	 * the end of the kernel (given current setup).
166 	 *
167 	 * To avoid freeing/using the wrong page (kernel sized) we:
168 	 *	- align up the beginning of initrd
169 	 *	- align down the end of initrd
170 	 *
171 	 *  |             |
172 	 *  |=============| a000
173 	 *  |             |
174 	 *  |             |
175 	 *  |             | 9000
176 	 *  |/////////////|
177 	 *  |/////////////|
178 	 *  |=============| 8000
179 	 *  |///INITRD////|
180 	 *  |/////////////|
181 	 *  |/////////////| 7000
182 	 *  |             |
183 	 *  |KKKKKKKKKKKKK|
184 	 *  |=============| 6000
185 	 *  |KKKKKKKKKKKKK|
186 	 *  |KKKKKKKKKKKKK|
187 	 *  K=kernel using 8KB pages
188 	 *
189 	 * In this example, we must free page 8000 ONLY. So we must align up
190 	 * initrd_start and keep initrd_end as is.
191 	 */
192 	start = PAGE_ALIGN(start);
193 	end = end & PAGE_MASK;
194 
195 	if (start < end)
196 		printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);
197 
198 	for (; start < end; start += PAGE_SIZE) {
199 		if (!virt_addr_valid(start))
200 			continue;
201 		free_reserved_page(virt_to_page(start));
202 	}
203 }
204 
205 /*
206  * This installs a clean page in the kernel's page table.
207  */
208 static struct page * __init
209 put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
210 {
211 	pgd_t *pgd;
212 	pud_t *pud;
213 	pmd_t *pmd;
214 	pte_t *pte;
215 
216 	pgd = pgd_offset_k(address);		/* note: this is NOT pgd_offset()! */
217 
218 	{
219 		pud = pud_alloc(&init_mm, pgd, address);
220 		if (!pud)
221 			goto out;
222 		pmd = pmd_alloc(&init_mm, pud, address);
223 		if (!pmd)
224 			goto out;
225 		pte = pte_alloc_kernel(pmd, address);
226 		if (!pte)
227 			goto out;
228 		if (!pte_none(*pte))
229 			goto out;
230 		set_pte(pte, mk_pte(page, pgprot));
231 	}
232   out:
233 	/* no need for flush_tlb */
234 	return page;
235 }
236 
237 static void __init
238 setup_gate (void)
239 {
240 	struct page *page;
241 
242 	/*
243 	 * Map the gate page twice: once read-only to export the ELF
244 	 * headers etc. and once execute-only page to enable
245 	 * privilege-promotion via "epc":
246 	 */
247 	page = virt_to_page(ia64_imva(__start_gate_section));
248 	put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
249 #ifdef HAVE_BUGGY_SEGREL
250 	page = virt_to_page(ia64_imva(__start_gate_section + PAGE_SIZE));
251 	put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
252 #else
253 	put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
254 	/* Fill in the holes (if any) with read-only zero pages: */
255 	{
256 		unsigned long addr;
257 
258 		for (addr = GATE_ADDR + PAGE_SIZE;
259 		     addr < GATE_ADDR + PERCPU_PAGE_SIZE;
260 		     addr += PAGE_SIZE)
261 		{
262 			put_kernel_page(ZERO_PAGE(0), addr,
263 					PAGE_READONLY);
264 			put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
265 					PAGE_READONLY);
266 		}
267 	}
268 #endif
269 	ia64_patch_gate();
270 }
271 
272 static struct vm_area_struct gate_vma;
273 
274 static int __init gate_vma_init(void)
275 {
276 	gate_vma.vm_mm = NULL;
277 	gate_vma.vm_start = FIXADDR_USER_START;
278 	gate_vma.vm_end = FIXADDR_USER_END;
279 	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
280 	gate_vma.vm_page_prot = __P101;
281 
282 	return 0;
283 }
284 __initcall(gate_vma_init);
285 
286 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
287 {
288 	return &gate_vma;
289 }
290 
291 int in_gate_area_no_mm(unsigned long addr)
292 {
293 	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
294 		return 1;
295 	return 0;
296 }
297 
298 int in_gate_area(struct mm_struct *mm, unsigned long addr)
299 {
300 	return in_gate_area_no_mm(addr);
301 }
302 
303 void ia64_mmu_init(void *my_cpu_data)
304 {
305 	unsigned long pta, impl_va_bits;
306 	extern void tlb_init(void);
307 
308 #ifdef CONFIG_DISABLE_VHPT
309 #	define VHPT_ENABLE_BIT	0
310 #else
311 #	define VHPT_ENABLE_BIT	1
312 #endif
313 
314 	/*
315 	 * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
316 	 * address space.  The IA-64 architecture guarantees that at least 50 bits of
317 	 * virtual address space are implemented but if we pick a large enough page size
318 	 * (e.g., 64KB), the mapped address space is big enough that it will overlap with
319 	 * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
320 	 * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
321 	 * problem in practice.  Alternatively, we could truncate the top of the mapped
322 	 * address space to not permit mappings that would overlap with the VMLPT.
323 	 * --davidm 00/12/06
324 	 */
325 #	define pte_bits			3
326 #	define mapped_space_bits	(3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
327 	/*
328 	 * The virtual page table has to cover the entire implemented address space within
329 	 * a region even though not all of this space may be mappable.  The reason for
330 	 * this is that the Access bit and Dirty bit fault handlers perform
331 	 * non-speculative accesses to the virtual page table, so the address range of the
332 	 * virtual page table itself needs to be covered by virtual page table.
333 	 */
334 #	define vmlpt_bits		(impl_va_bits - PAGE_SHIFT + pte_bits)
335 #	define POW2(n)			(1ULL << (n))
336 
337 	impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));
338 
339 	if (impl_va_bits < 51 || impl_va_bits > 61)
340 		panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
341 	/*
342 	 * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
343 	 * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
344 	 * the test makes sure that our mapped space doesn't overlap the
345 	 * unimplemented hole in the middle of the region.
346 	 */
347 	if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
348 	    (mapped_space_bits > impl_va_bits - 1))
349 		panic("Cannot build a big enough virtual-linear page table"
350 		      " to cover mapped address space.\n"
351 		      " Try using a smaller page size.\n");
352 
353 
354 	/* place the VMLPT at the end of each page-table mapped region: */
355 	pta = POW2(61) - POW2(vmlpt_bits);
356 
357 	/*
358 	 * Set the (virtually mapped linear) page table address.  Bit
359 	 * 8 selects between the short and long format, bits 2-7 the
360 	 * size of the table, and bit 0 whether the VHPT walker is
361 	 * enabled.
362 	 */
363 	ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);
364 
365 	ia64_tlb_init();
366 
367 #ifdef	CONFIG_HUGETLB_PAGE
368 	ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
369 	ia64_srlz_d();
370 #endif
371 }
372 
373 #ifdef CONFIG_VIRTUAL_MEM_MAP
374 int vmemmap_find_next_valid_pfn(int node, int i)
375 {
376 	unsigned long end_address, hole_next_pfn;
377 	unsigned long stop_address;
378 	pg_data_t *pgdat = NODE_DATA(node);
379 
380 	end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
381 	end_address = PAGE_ALIGN(end_address);
382 	stop_address = (unsigned long) &vmem_map[pgdat_end_pfn(pgdat)];
383 
384 	do {
385 		pgd_t *pgd;
386 		pud_t *pud;
387 		pmd_t *pmd;
388 		pte_t *pte;
389 
390 		pgd = pgd_offset_k(end_address);
391 		if (pgd_none(*pgd)) {
392 			end_address += PGDIR_SIZE;
393 			continue;
394 		}
395 
396 		pud = pud_offset(pgd, end_address);
397 		if (pud_none(*pud)) {
398 			end_address += PUD_SIZE;
399 			continue;
400 		}
401 
402 		pmd = pmd_offset(pud, end_address);
403 		if (pmd_none(*pmd)) {
404 			end_address += PMD_SIZE;
405 			continue;
406 		}
407 
408 		pte = pte_offset_kernel(pmd, end_address);
409 retry_pte:
410 		if (pte_none(*pte)) {
411 			end_address += PAGE_SIZE;
412 			pte++;
413 			if ((end_address < stop_address) &&
414 			    (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
415 				goto retry_pte;
416 			continue;
417 		}
418 		/* Found next valid vmem_map page */
419 		break;
420 	} while (end_address < stop_address);
421 
422 	end_address = min(end_address, stop_address);
423 	end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
424 	hole_next_pfn = end_address / sizeof(struct page);
425 	return hole_next_pfn - pgdat->node_start_pfn;
426 }
427 
428 int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
429 {
430 	unsigned long address, start_page, end_page;
431 	struct page *map_start, *map_end;
432 	int node;
433 	pgd_t *pgd;
434 	pud_t *pud;
435 	pmd_t *pmd;
436 	pte_t *pte;
437 
438 	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
439 	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
440 
441 	start_page = (unsigned long) map_start & PAGE_MASK;
442 	end_page = PAGE_ALIGN((unsigned long) map_end);
443 	node = paddr_to_nid(__pa(start));
444 
445 	for (address = start_page; address < end_page; address += PAGE_SIZE) {
446 		pgd = pgd_offset_k(address);
447 		if (pgd_none(*pgd))
448 			pgd_populate(&init_mm, pgd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
449 		pud = pud_offset(pgd, address);
450 
451 		if (pud_none(*pud))
452 			pud_populate(&init_mm, pud, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
453 		pmd = pmd_offset(pud, address);
454 
455 		if (pmd_none(*pmd))
456 			pmd_populate_kernel(&init_mm, pmd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
457 		pte = pte_offset_kernel(pmd, address);
458 
459 		if (pte_none(*pte))
460 			set_pte(pte, pfn_pte(__pa(alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE)) >> PAGE_SHIFT,
461 					     PAGE_KERNEL));
462 	}
463 	return 0;
464 }
465 
466 struct memmap_init_callback_data {
467 	struct page *start;
468 	struct page *end;
469 	int nid;
470 	unsigned long zone;
471 };
472 
473 static int __meminit
474 virtual_memmap_init(u64 start, u64 end, void *arg)
475 {
476 	struct memmap_init_callback_data *args;
477 	struct page *map_start, *map_end;
478 
479 	args = (struct memmap_init_callback_data *) arg;
480 	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
481 	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
482 
483 	if (map_start < args->start)
484 		map_start = args->start;
485 	if (map_end > args->end)
486 		map_end = args->end;
487 
488 	/*
489 	 * We have to initialize "out of bounds" struct page elements that fit completely
490 	 * on the same pages that were allocated for the "in bounds" elements because they
491 	 * may be referenced later (and found to be "reserved").
492 	 */
493 	map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
494 	map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
495 		    / sizeof(struct page));
496 
497 	if (map_start < map_end)
498 		memmap_init_zone((unsigned long)(map_end - map_start),
499 				 args->nid, args->zone, page_to_pfn(map_start),
500 				 MEMMAP_EARLY, NULL);
501 	return 0;
502 }
503 
504 void __meminit
505 memmap_init (unsigned long size, int nid, unsigned long zone,
506 	     unsigned long start_pfn)
507 {
508 	if (!vmem_map) {
509 		memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY,
510 				NULL);
511 	} else {
512 		struct page *start;
513 		struct memmap_init_callback_data args;
514 
515 		start = pfn_to_page(start_pfn);
516 		args.start = start;
517 		args.end = start + size;
518 		args.nid = nid;
519 		args.zone = zone;
520 
521 		efi_memmap_walk(virtual_memmap_init, &args);
522 	}
523 }
524 
525 int
526 ia64_pfn_valid (unsigned long pfn)
527 {
528 	char byte;
529 	struct page *pg = pfn_to_page(pfn);
530 
531 	return     (__get_user(byte, (char __user *) pg) == 0)
532 		&& ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
533 			|| (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
534 }
535 EXPORT_SYMBOL(ia64_pfn_valid);
536 
537 int __init find_largest_hole(u64 start, u64 end, void *arg)
538 {
539 	u64 *max_gap = arg;
540 
541 	static u64 last_end = PAGE_OFFSET;
542 
543 	/* NOTE: this algorithm assumes efi memmap table is ordered */
544 
545 	if (*max_gap < (start - last_end))
546 		*max_gap = start - last_end;
547 	last_end = end;
548 	return 0;
549 }
550 
551 #endif /* CONFIG_VIRTUAL_MEM_MAP */
552 
553 int __init register_active_ranges(u64 start, u64 len, int nid)
554 {
555 	u64 end = start + len;
556 
557 #ifdef CONFIG_KEXEC
558 	if (start > crashk_res.start && start < crashk_res.end)
559 		start = crashk_res.end;
560 	if (end > crashk_res.start && end < crashk_res.end)
561 		end = crashk_res.start;
562 #endif
563 
564 	if (start < end)
565 		memblock_add_node(__pa(start), end - start, nid);
566 	return 0;
567 }
568 
569 int
570 find_max_min_low_pfn (u64 start, u64 end, void *arg)
571 {
572 	unsigned long pfn_start, pfn_end;
573 #ifdef CONFIG_FLATMEM
574 	pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
575 	pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
576 #else
577 	pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
578 	pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
579 #endif
580 	min_low_pfn = min(min_low_pfn, pfn_start);
581 	max_low_pfn = max(max_low_pfn, pfn_end);
582 	return 0;
583 }
584 
585 /*
586  * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
587  * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
588  * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
589  * useful for performance testing, but conceivably could also come in handy for debugging
590  * purposes.
591  */
592 
593 static int nolwsys __initdata;
594 
595 static int __init
596 nolwsys_setup (char *s)
597 {
598 	nolwsys = 1;
599 	return 1;
600 }
601 
602 __setup("nolwsys", nolwsys_setup);
603 
604 void __init
605 mem_init (void)
606 {
607 	int i;
608 
609 	BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
610 	BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
611 	BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
612 
613 #ifdef CONFIG_PCI
614 	/*
615 	 * This needs to be called _after_ the command line has been parsed but _before_
616 	 * any drivers that may need the PCI DMA interface are initialized or bootmem has
617 	 * been freed.
618 	 */
619 	platform_dma_init();
620 #endif
621 
622 #ifdef CONFIG_FLATMEM
623 	BUG_ON(!mem_map);
624 #endif
625 
626 	set_max_mapnr(max_low_pfn);
627 	high_memory = __va(max_low_pfn * PAGE_SIZE);
628 	free_all_bootmem();
629 	mem_init_print_info(NULL);
630 
631 	/*
632 	 * For fsyscall entrpoints with no light-weight handler, use the ordinary
633 	 * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
634 	 * code can tell them apart.
635 	 */
636 	for (i = 0; i < NR_syscalls; ++i) {
637 		extern unsigned long fsyscall_table[NR_syscalls];
638 		extern unsigned long sys_call_table[NR_syscalls];
639 
640 		if (!fsyscall_table[i] || nolwsys)
641 			fsyscall_table[i] = sys_call_table[i] | 1;
642 	}
643 	setup_gate();
644 }
645 
646 #ifdef CONFIG_MEMORY_HOTPLUG
647 int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap,
648 		bool want_memblock)
649 {
650 	unsigned long start_pfn = start >> PAGE_SHIFT;
651 	unsigned long nr_pages = size >> PAGE_SHIFT;
652 	int ret;
653 
654 	ret = __add_pages(nid, start_pfn, nr_pages, altmap, want_memblock);
655 	if (ret)
656 		printk("%s: Problem encountered in __add_pages() as ret=%d\n",
657 		       __func__,  ret);
658 
659 	return ret;
660 }
661 
662 #ifdef CONFIG_MEMORY_HOTREMOVE
663 int arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
664 {
665 	unsigned long start_pfn = start >> PAGE_SHIFT;
666 	unsigned long nr_pages = size >> PAGE_SHIFT;
667 	struct zone *zone;
668 	int ret;
669 
670 	zone = page_zone(pfn_to_page(start_pfn));
671 	ret = __remove_pages(zone, start_pfn, nr_pages, altmap);
672 	if (ret)
673 		pr_warn("%s: Problem encountered in __remove_pages() as"
674 			" ret=%d\n", __func__,  ret);
675 
676 	return ret;
677 }
678 #endif
679 #endif
680