xref: /kernel/linux/linux-5.10/arch/ia64/mm/init.c (revision 8c2ecf20)
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-map-ops.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_dma_mark_clean(phys_addr_t paddr, size_t size)
77{
78	unsigned long pfn = PHYS_PFN(paddr);
79
80	do {
81		set_bit(PG_arch_1, &pfn_to_page(pfn)->flags);
82	} while (++pfn <= PHYS_PFN(paddr + size - 1));
83}
84
85inline void
86ia64_set_rbs_bot (void)
87{
88	unsigned long stack_size = rlimit_max(RLIMIT_STACK) & -16;
89
90	if (stack_size > MAX_USER_STACK_SIZE)
91		stack_size = MAX_USER_STACK_SIZE;
92	current->thread.rbs_bot = PAGE_ALIGN(current->mm->start_stack - stack_size);
93}
94
95/*
96 * This performs some platform-dependent address space initialization.
97 * On IA-64, we want to setup the VM area for the register backing
98 * store (which grows upwards) and install the gateway page which is
99 * used for signal trampolines, etc.
100 */
101void
102ia64_init_addr_space (void)
103{
104	struct vm_area_struct *vma;
105
106	ia64_set_rbs_bot();
107
108	/*
109	 * If we're out of memory and kmem_cache_alloc() returns NULL, we simply ignore
110	 * the problem.  When the process attempts to write to the register backing store
111	 * for the first time, it will get a SEGFAULT in this case.
112	 */
113	vma = vm_area_alloc(current->mm);
114	if (vma) {
115		vma_set_anonymous(vma);
116		vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
117		vma->vm_end = vma->vm_start + PAGE_SIZE;
118		vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
119		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
120		mmap_write_lock(current->mm);
121		if (insert_vm_struct(current->mm, vma)) {
122			mmap_write_unlock(current->mm);
123			vm_area_free(vma);
124			return;
125		}
126		mmap_write_unlock(current->mm);
127	}
128
129	/* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
130	if (!(current->personality & MMAP_PAGE_ZERO)) {
131		vma = vm_area_alloc(current->mm);
132		if (vma) {
133			vma_set_anonymous(vma);
134			vma->vm_end = PAGE_SIZE;
135			vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
136			vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
137					VM_DONTEXPAND | VM_DONTDUMP;
138			mmap_write_lock(current->mm);
139			if (insert_vm_struct(current->mm, vma)) {
140				mmap_write_unlock(current->mm);
141				vm_area_free(vma);
142				return;
143			}
144			mmap_write_unlock(current->mm);
145		}
146	}
147}
148
149void
150free_initmem (void)
151{
152	free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
153			   -1, "unused kernel");
154}
155
156void __init
157free_initrd_mem (unsigned long start, unsigned long end)
158{
159	/*
160	 * EFI uses 4KB pages while the kernel can use 4KB or bigger.
161	 * Thus EFI and the kernel may have different page sizes. It is
162	 * therefore possible to have the initrd share the same page as
163	 * the end of the kernel (given current setup).
164	 *
165	 * To avoid freeing/using the wrong page (kernel sized) we:
166	 *	- align up the beginning of initrd
167	 *	- align down the end of initrd
168	 *
169	 *  |             |
170	 *  |=============| a000
171	 *  |             |
172	 *  |             |
173	 *  |             | 9000
174	 *  |/////////////|
175	 *  |/////////////|
176	 *  |=============| 8000
177	 *  |///INITRD////|
178	 *  |/////////////|
179	 *  |/////////////| 7000
180	 *  |             |
181	 *  |KKKKKKKKKKKKK|
182	 *  |=============| 6000
183	 *  |KKKKKKKKKKKKK|
184	 *  |KKKKKKKKKKKKK|
185	 *  K=kernel using 8KB pages
186	 *
187	 * In this example, we must free page 8000 ONLY. So we must align up
188	 * initrd_start and keep initrd_end as is.
189	 */
190	start = PAGE_ALIGN(start);
191	end = end & PAGE_MASK;
192
193	if (start < end)
194		printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);
195
196	for (; start < end; start += PAGE_SIZE) {
197		if (!virt_addr_valid(start))
198			continue;
199		free_reserved_page(virt_to_page(start));
200	}
201}
202
203/*
204 * This installs a clean page in the kernel's page table.
205 */
206static struct page * __init
207put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
208{
209	pgd_t *pgd;
210	p4d_t *p4d;
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		p4d = p4d_alloc(&init_mm, pgd, address);
219		if (!p4d)
220			goto out;
221		pud = pud_alloc(&init_mm, p4d, address);
222		if (!pud)
223			goto out;
224		pmd = pmd_alloc(&init_mm, pud, address);
225		if (!pmd)
226			goto out;
227		pte = pte_alloc_kernel(pmd, address);
228		if (!pte)
229			goto out;
230		if (!pte_none(*pte))
231			goto out;
232		set_pte(pte, mk_pte(page, pgprot));
233	}
234  out:
235	/* no need for flush_tlb */
236	return page;
237}
238
239static void __init
240setup_gate (void)
241{
242	struct page *page;
243
244	/*
245	 * Map the gate page twice: once read-only to export the ELF
246	 * headers etc. and once execute-only page to enable
247	 * privilege-promotion via "epc":
248	 */
249	page = virt_to_page(ia64_imva(__start_gate_section));
250	put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
251#ifdef HAVE_BUGGY_SEGREL
252	page = virt_to_page(ia64_imva(__start_gate_section + PAGE_SIZE));
253	put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
254#else
255	put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
256	/* Fill in the holes (if any) with read-only zero pages: */
257	{
258		unsigned long addr;
259
260		for (addr = GATE_ADDR + PAGE_SIZE;
261		     addr < GATE_ADDR + PERCPU_PAGE_SIZE;
262		     addr += PAGE_SIZE)
263		{
264			put_kernel_page(ZERO_PAGE(0), addr,
265					PAGE_READONLY);
266			put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
267					PAGE_READONLY);
268		}
269	}
270#endif
271	ia64_patch_gate();
272}
273
274static struct vm_area_struct gate_vma;
275
276static int __init gate_vma_init(void)
277{
278	vma_init(&gate_vma, NULL);
279	gate_vma.vm_start = FIXADDR_USER_START;
280	gate_vma.vm_end = FIXADDR_USER_END;
281	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
282	gate_vma.vm_page_prot = __P101;
283
284	return 0;
285}
286__initcall(gate_vma_init);
287
288struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
289{
290	return &gate_vma;
291}
292
293int in_gate_area_no_mm(unsigned long addr)
294{
295	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
296		return 1;
297	return 0;
298}
299
300int in_gate_area(struct mm_struct *mm, unsigned long addr)
301{
302	return in_gate_area_no_mm(addr);
303}
304
305void ia64_mmu_init(void *my_cpu_data)
306{
307	unsigned long pta, impl_va_bits;
308	extern void tlb_init(void);
309
310#ifdef CONFIG_DISABLE_VHPT
311#	define VHPT_ENABLE_BIT	0
312#else
313#	define VHPT_ENABLE_BIT	1
314#endif
315
316	/*
317	 * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
318	 * address space.  The IA-64 architecture guarantees that at least 50 bits of
319	 * virtual address space are implemented but if we pick a large enough page size
320	 * (e.g., 64KB), the mapped address space is big enough that it will overlap with
321	 * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
322	 * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
323	 * problem in practice.  Alternatively, we could truncate the top of the mapped
324	 * address space to not permit mappings that would overlap with the VMLPT.
325	 * --davidm 00/12/06
326	 */
327#	define pte_bits			3
328#	define mapped_space_bits	(3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
329	/*
330	 * The virtual page table has to cover the entire implemented address space within
331	 * a region even though not all of this space may be mappable.  The reason for
332	 * this is that the Access bit and Dirty bit fault handlers perform
333	 * non-speculative accesses to the virtual page table, so the address range of the
334	 * virtual page table itself needs to be covered by virtual page table.
335	 */
336#	define vmlpt_bits		(impl_va_bits - PAGE_SHIFT + pte_bits)
337#	define POW2(n)			(1ULL << (n))
338
339	impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));
340
341	if (impl_va_bits < 51 || impl_va_bits > 61)
342		panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
343	/*
344	 * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
345	 * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
346	 * the test makes sure that our mapped space doesn't overlap the
347	 * unimplemented hole in the middle of the region.
348	 */
349	if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
350	    (mapped_space_bits > impl_va_bits - 1))
351		panic("Cannot build a big enough virtual-linear page table"
352		      " to cover mapped address space.\n"
353		      " Try using a smaller page size.\n");
354
355
356	/* place the VMLPT at the end of each page-table mapped region: */
357	pta = POW2(61) - POW2(vmlpt_bits);
358
359	/*
360	 * Set the (virtually mapped linear) page table address.  Bit
361	 * 8 selects between the short and long format, bits 2-7 the
362	 * size of the table, and bit 0 whether the VHPT walker is
363	 * enabled.
364	 */
365	ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);
366
367	ia64_tlb_init();
368
369#ifdef	CONFIG_HUGETLB_PAGE
370	ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
371	ia64_srlz_d();
372#endif
373}
374
375#ifdef CONFIG_VIRTUAL_MEM_MAP
376int vmemmap_find_next_valid_pfn(int node, int i)
377{
378	unsigned long end_address, hole_next_pfn;
379	unsigned long stop_address;
380	pg_data_t *pgdat = NODE_DATA(node);
381
382	end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
383	end_address = PAGE_ALIGN(end_address);
384	stop_address = (unsigned long) &vmem_map[pgdat_end_pfn(pgdat)];
385
386	do {
387		pgd_t *pgd;
388		p4d_t *p4d;
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		p4d = p4d_offset(pgd, end_address);
400		if (p4d_none(*p4d)) {
401			end_address += P4D_SIZE;
402			continue;
403		}
404
405		pud = pud_offset(p4d, end_address);
406		if (pud_none(*pud)) {
407			end_address += PUD_SIZE;
408			continue;
409		}
410
411		pmd = pmd_offset(pud, end_address);
412		if (pmd_none(*pmd)) {
413			end_address += PMD_SIZE;
414			continue;
415		}
416
417		pte = pte_offset_kernel(pmd, end_address);
418retry_pte:
419		if (pte_none(*pte)) {
420			end_address += PAGE_SIZE;
421			pte++;
422			if ((end_address < stop_address) &&
423			    (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
424				goto retry_pte;
425			continue;
426		}
427		/* Found next valid vmem_map page */
428		break;
429	} while (end_address < stop_address);
430
431	end_address = min(end_address, stop_address);
432	end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
433	hole_next_pfn = end_address / sizeof(struct page);
434	return hole_next_pfn - pgdat->node_start_pfn;
435}
436
437int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
438{
439	unsigned long address, start_page, end_page;
440	struct page *map_start, *map_end;
441	int node;
442	pgd_t *pgd;
443	p4d_t *p4d;
444	pud_t *pud;
445	pmd_t *pmd;
446	pte_t *pte;
447
448	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
449	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
450
451	start_page = (unsigned long) map_start & PAGE_MASK;
452	end_page = PAGE_ALIGN((unsigned long) map_end);
453	node = paddr_to_nid(__pa(start));
454
455	for (address = start_page; address < end_page; address += PAGE_SIZE) {
456		pgd = pgd_offset_k(address);
457		if (pgd_none(*pgd)) {
458			p4d = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
459			if (!p4d)
460				goto err_alloc;
461			pgd_populate(&init_mm, pgd, p4d);
462		}
463		p4d = p4d_offset(pgd, address);
464
465		if (p4d_none(*p4d)) {
466			pud = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
467			if (!pud)
468				goto err_alloc;
469			p4d_populate(&init_mm, p4d, pud);
470		}
471		pud = pud_offset(p4d, address);
472
473		if (pud_none(*pud)) {
474			pmd = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
475			if (!pmd)
476				goto err_alloc;
477			pud_populate(&init_mm, pud, pmd);
478		}
479		pmd = pmd_offset(pud, address);
480
481		if (pmd_none(*pmd)) {
482			pte = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
483			if (!pte)
484				goto err_alloc;
485			pmd_populate_kernel(&init_mm, pmd, pte);
486		}
487		pte = pte_offset_kernel(pmd, address);
488
489		if (pte_none(*pte)) {
490			void *page = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE,
491							 node);
492			if (!page)
493				goto err_alloc;
494			set_pte(pte, pfn_pte(__pa(page) >> PAGE_SHIFT,
495					     PAGE_KERNEL));
496		}
497	}
498	return 0;
499
500err_alloc:
501	panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d\n",
502	      __func__, PAGE_SIZE, PAGE_SIZE, node);
503	return -ENOMEM;
504}
505
506struct memmap_init_callback_data {
507	struct page *start;
508	struct page *end;
509	int nid;
510	unsigned long zone;
511};
512
513static int __meminit
514virtual_memmap_init(u64 start, u64 end, void *arg)
515{
516	struct memmap_init_callback_data *args;
517	struct page *map_start, *map_end;
518
519	args = (struct memmap_init_callback_data *) arg;
520	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
521	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
522
523	if (map_start < args->start)
524		map_start = args->start;
525	if (map_end > args->end)
526		map_end = args->end;
527
528	/*
529	 * We have to initialize "out of bounds" struct page elements that fit completely
530	 * on the same pages that were allocated for the "in bounds" elements because they
531	 * may be referenced later (and found to be "reserved").
532	 */
533	map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
534	map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
535		    / sizeof(struct page));
536
537	if (map_start < map_end)
538		memmap_init_zone((unsigned long)(map_end - map_start),
539				 args->nid, args->zone, page_to_pfn(map_start), page_to_pfn(map_end),
540				 MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
541	return 0;
542}
543
544void __meminit
545arch_memmap_init (unsigned long size, int nid, unsigned long zone,
546	     unsigned long start_pfn)
547{
548	if (!vmem_map) {
549		memmap_init_zone(size, nid, zone, start_pfn, start_pfn + size,
550				 MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
551	} else {
552		struct page *start;
553		struct memmap_init_callback_data args;
554
555		start = pfn_to_page(start_pfn);
556		args.start = start;
557		args.end = start + size;
558		args.nid = nid;
559		args.zone = zone;
560
561		efi_memmap_walk(virtual_memmap_init, &args);
562	}
563}
564
565void __init memmap_init(void)
566{
567}
568
569int
570ia64_pfn_valid (unsigned long pfn)
571{
572	char byte;
573	struct page *pg = pfn_to_page(pfn);
574
575	return     (__get_user(byte, (char __user *) pg) == 0)
576		&& ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
577			|| (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
578}
579EXPORT_SYMBOL(ia64_pfn_valid);
580
581int __init find_largest_hole(u64 start, u64 end, void *arg)
582{
583	u64 *max_gap = arg;
584
585	static u64 last_end = PAGE_OFFSET;
586
587	/* NOTE: this algorithm assumes efi memmap table is ordered */
588
589	if (*max_gap < (start - last_end))
590		*max_gap = start - last_end;
591	last_end = end;
592	return 0;
593}
594
595#endif /* CONFIG_VIRTUAL_MEM_MAP */
596
597int __init register_active_ranges(u64 start, u64 len, int nid)
598{
599	u64 end = start + len;
600
601#ifdef CONFIG_KEXEC
602	if (start > crashk_res.start && start < crashk_res.end)
603		start = crashk_res.end;
604	if (end > crashk_res.start && end < crashk_res.end)
605		end = crashk_res.start;
606#endif
607
608	if (start < end)
609		memblock_add_node(__pa(start), end - start, nid);
610	return 0;
611}
612
613int
614find_max_min_low_pfn (u64 start, u64 end, void *arg)
615{
616	unsigned long pfn_start, pfn_end;
617#ifdef CONFIG_FLATMEM
618	pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
619	pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
620#else
621	pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
622	pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
623#endif
624	min_low_pfn = min(min_low_pfn, pfn_start);
625	max_low_pfn = max(max_low_pfn, pfn_end);
626	return 0;
627}
628
629/*
630 * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
631 * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
632 * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
633 * useful for performance testing, but conceivably could also come in handy for debugging
634 * purposes.
635 */
636
637static int nolwsys __initdata;
638
639static int __init
640nolwsys_setup (char *s)
641{
642	nolwsys = 1;
643	return 1;
644}
645
646__setup("nolwsys", nolwsys_setup);
647
648void __init
649mem_init (void)
650{
651	int i;
652
653	BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
654	BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
655	BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
656
657	/*
658	 * This needs to be called _after_ the command line has been parsed but
659	 * _before_ any drivers that may need the PCI DMA interface are
660	 * initialized or bootmem has been freed.
661	 */
662#ifdef CONFIG_INTEL_IOMMU
663	detect_intel_iommu();
664	if (!iommu_detected)
665#endif
666#ifdef CONFIG_SWIOTLB
667		swiotlb_init(1);
668#endif
669
670#ifdef CONFIG_FLATMEM
671	BUG_ON(!mem_map);
672#endif
673
674	set_max_mapnr(max_low_pfn);
675	high_memory = __va(max_low_pfn * PAGE_SIZE);
676	memblock_free_all();
677	mem_init_print_info(NULL);
678
679	/*
680	 * For fsyscall entrpoints with no light-weight handler, use the ordinary
681	 * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
682	 * code can tell them apart.
683	 */
684	for (i = 0; i < NR_syscalls; ++i) {
685		extern unsigned long fsyscall_table[NR_syscalls];
686		extern unsigned long sys_call_table[NR_syscalls];
687
688		if (!fsyscall_table[i] || nolwsys)
689			fsyscall_table[i] = sys_call_table[i] | 1;
690	}
691	setup_gate();
692}
693
694#ifdef CONFIG_MEMORY_HOTPLUG
695int arch_add_memory(int nid, u64 start, u64 size,
696		    struct mhp_params *params)
697{
698	unsigned long start_pfn = start >> PAGE_SHIFT;
699	unsigned long nr_pages = size >> PAGE_SHIFT;
700	int ret;
701
702	if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot))
703		return -EINVAL;
704
705	ret = __add_pages(nid, start_pfn, nr_pages, params);
706	if (ret)
707		printk("%s: Problem encountered in __add_pages() as ret=%d\n",
708		       __func__,  ret);
709
710	return ret;
711}
712
713void arch_remove_memory(int nid, u64 start, u64 size,
714			struct vmem_altmap *altmap)
715{
716	unsigned long start_pfn = start >> PAGE_SHIFT;
717	unsigned long nr_pages = size >> PAGE_SHIFT;
718
719	__remove_pages(start_pfn, nr_pages, altmap);
720}
721#endif
722