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  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(phys_addr_t paddr, size_t size,
 77		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		mmap_write_lock(current->mm);
122		if (insert_vm_struct(current->mm, vma)) {
123			mmap_write_unlock(current->mm);
124			vm_area_free(vma);
125			return;
126		}
127		mmap_write_unlock(current->mm);
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			mmap_write_lock(current->mm);
140			if (insert_vm_struct(current->mm, vma)) {
141				mmap_write_unlock(current->mm);
142				vm_area_free(vma);
143				return;
144			}
145			mmap_write_unlock(current->mm);
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	p4d_t *p4d;
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		p4d = p4d_alloc(&init_mm, pgd, address);
220		if (!p4d)
221			goto out;
222		pud = pud_alloc(&init_mm, p4d, 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
240static void __init
241setup_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
275static struct vm_area_struct gate_vma;
276
277static int __init gate_vma_init(void)
278{
279	vma_init(&gate_vma, 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
289struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
290{
291	return &gate_vma;
292}
293
294int 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
301int in_gate_area(struct mm_struct *mm, unsigned long addr)
302{
303	return in_gate_area_no_mm(addr);
304}
305
306void 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
377int 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		p4d_t *p4d;
390		pud_t *pud;
391		pmd_t *pmd;
392		pte_t *pte;
393
394		pgd = pgd_offset_k(end_address);
395		if (pgd_none(*pgd)) {
396			end_address += PGDIR_SIZE;
397			continue;
398		}
399
400		p4d = p4d_offset(pgd, end_address);
401		if (p4d_none(*p4d)) {
402			end_address += P4D_SIZE;
403			continue;
404		}
405
406		pud = pud_offset(p4d, end_address);
407		if (pud_none(*pud)) {
408			end_address += PUD_SIZE;
409			continue;
410		}
411
412		pmd = pmd_offset(pud, end_address);
413		if (pmd_none(*pmd)) {
414			end_address += PMD_SIZE;
415			continue;
416		}
417
418		pte = pte_offset_kernel(pmd, end_address);
419retry_pte:
420		if (pte_none(*pte)) {
421			end_address += PAGE_SIZE;
422			pte++;
423			if ((end_address < stop_address) &&
424			    (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
425				goto retry_pte;
426			continue;
427		}
428		/* Found next valid vmem_map page */
429		break;
430	} while (end_address < stop_address);
431
432	end_address = min(end_address, stop_address);
433	end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
434	hole_next_pfn = end_address / sizeof(struct page);
435	return hole_next_pfn - pgdat->node_start_pfn;
436}
437
438int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
439{
440	unsigned long address, start_page, end_page;
441	struct page *map_start, *map_end;
442	int node;
443	pgd_t *pgd;
444	p4d_t *p4d;
445	pud_t *pud;
446	pmd_t *pmd;
447	pte_t *pte;
448
449	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
450	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
451
452	start_page = (unsigned long) map_start & PAGE_MASK;
453	end_page = PAGE_ALIGN((unsigned long) map_end);
454	node = paddr_to_nid(__pa(start));
455
456	for (address = start_page; address < end_page; address += PAGE_SIZE) {
457		pgd = pgd_offset_k(address);
458		if (pgd_none(*pgd)) {
459			p4d = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
460			if (!p4d)
461				goto err_alloc;
462			pgd_populate(&init_mm, pgd, p4d);
463		}
464		p4d = p4d_offset(pgd, address);
465
466		if (p4d_none(*p4d)) {
467			pud = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
468			if (!pud)
469				goto err_alloc;
470			p4d_populate(&init_mm, p4d, pud);
471		}
472		pud = pud_offset(p4d, address);
473
474		if (pud_none(*pud)) {
475			pmd = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
476			if (!pmd)
477				goto err_alloc;
478			pud_populate(&init_mm, pud, pmd);
479		}
480		pmd = pmd_offset(pud, address);
481
482		if (pmd_none(*pmd)) {
483			pte = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
484			if (!pte)
485				goto err_alloc;
486			pmd_populate_kernel(&init_mm, pmd, pte);
487		}
488		pte = pte_offset_kernel(pmd, address);
489
490		if (pte_none(*pte)) {
491			void *page = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE,
492							 node);
493			if (!page)
494				goto err_alloc;
495			set_pte(pte, pfn_pte(__pa(page) >> PAGE_SHIFT,
496					     PAGE_KERNEL));
497		}
498	}
499	return 0;
500
501err_alloc:
502	panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d\n",
503	      __func__, PAGE_SIZE, PAGE_SIZE, node);
504	return -ENOMEM;
505}
506
507struct memmap_init_callback_data {
508	struct page *start;
509	struct page *end;
510	int nid;
511	unsigned long zone;
512};
513
514static int __meminit
515virtual_memmap_init(u64 start, u64 end, void *arg)
516{
517	struct memmap_init_callback_data *args;
518	struct page *map_start, *map_end;
519
520	args = (struct memmap_init_callback_data *) arg;
521	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
522	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
523
524	if (map_start < args->start)
525		map_start = args->start;
526	if (map_end > args->end)
527		map_end = args->end;
528
529	/*
530	 * We have to initialize "out of bounds" struct page elements that fit completely
531	 * on the same pages that were allocated for the "in bounds" elements because they
532	 * may be referenced later (and found to be "reserved").
533	 */
534	map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
535	map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
536		    / sizeof(struct page));
537
538	if (map_start < map_end)
539		memmap_init_zone((unsigned long)(map_end - map_start),
540				 args->nid, args->zone, page_to_pfn(map_start),
541				 MEMINIT_EARLY, NULL);
542	return 0;
543}
544
545void __meminit
546memmap_init (unsigned long size, int nid, unsigned long zone,
547	     unsigned long start_pfn)
548{
549	if (!vmem_map) {
550		memmap_init_zone(size, nid, zone, start_pfn,
551				 MEMINIT_EARLY, NULL);
552	} else {
553		struct page *start;
554		struct memmap_init_callback_data args;
555
556		start = pfn_to_page(start_pfn);
557		args.start = start;
558		args.end = start + size;
559		args.nid = nid;
560		args.zone = zone;
561
562		efi_memmap_walk(virtual_memmap_init, &args);
563	}
564}
565
566int
567ia64_pfn_valid (unsigned long pfn)
568{
569	char byte;
570	struct page *pg = pfn_to_page(pfn);
571
572	return     (__get_user(byte, (char __user *) pg) == 0)
573		&& ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
574			|| (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
575}
576EXPORT_SYMBOL(ia64_pfn_valid);
577
578int __init find_largest_hole(u64 start, u64 end, void *arg)
579{
580	u64 *max_gap = arg;
581
582	static u64 last_end = PAGE_OFFSET;
583
584	/* NOTE: this algorithm assumes efi memmap table is ordered */
585
586	if (*max_gap < (start - last_end))
587		*max_gap = start - last_end;
588	last_end = end;
589	return 0;
590}
591
592#endif /* CONFIG_VIRTUAL_MEM_MAP */
593
594int __init register_active_ranges(u64 start, u64 len, int nid)
595{
596	u64 end = start + len;
597
598#ifdef CONFIG_KEXEC
599	if (start > crashk_res.start && start < crashk_res.end)
600		start = crashk_res.end;
601	if (end > crashk_res.start && end < crashk_res.end)
602		end = crashk_res.start;
603#endif
604
605	if (start < end)
606		memblock_add_node(__pa(start), end - start, nid);
607	return 0;
608}
609
610int
611find_max_min_low_pfn (u64 start, u64 end, void *arg)
612{
613	unsigned long pfn_start, pfn_end;
614#ifdef CONFIG_FLATMEM
615	pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
616	pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
617#else
618	pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
619	pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
620#endif
621	min_low_pfn = min(min_low_pfn, pfn_start);
622	max_low_pfn = max(max_low_pfn, pfn_end);
623	return 0;
624}
625
626/*
627 * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
628 * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
629 * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
630 * useful for performance testing, but conceivably could also come in handy for debugging
631 * purposes.
632 */
633
634static int nolwsys __initdata;
635
636static int __init
637nolwsys_setup (char *s)
638{
639	nolwsys = 1;
640	return 1;
641}
642
643__setup("nolwsys", nolwsys_setup);
644
645void __init
646mem_init (void)
647{
648	int i;
649
650	BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
651	BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
652	BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
653
654	/*
655	 * This needs to be called _after_ the command line has been parsed but
656	 * _before_ any drivers that may need the PCI DMA interface are
657	 * initialized or bootmem has been freed.
658	 */
659#ifdef CONFIG_INTEL_IOMMU
660	detect_intel_iommu();
661	if (!iommu_detected)
662#endif
663#ifdef CONFIG_SWIOTLB
664		swiotlb_init(1);
665#endif
666
667#ifdef CONFIG_FLATMEM
668	BUG_ON(!mem_map);
669#endif
670
671	set_max_mapnr(max_low_pfn);
672	high_memory = __va(max_low_pfn * PAGE_SIZE);
673	memblock_free_all();
674	mem_init_print_info(NULL);
675
676	/*
677	 * For fsyscall entrpoints with no light-weight handler, use the ordinary
678	 * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
679	 * code can tell them apart.
680	 */
681	for (i = 0; i < NR_syscalls; ++i) {
682		extern unsigned long fsyscall_table[NR_syscalls];
683		extern unsigned long sys_call_table[NR_syscalls];
684
685		if (!fsyscall_table[i] || nolwsys)
686			fsyscall_table[i] = sys_call_table[i] | 1;
687	}
688	setup_gate();
689}
690
691#ifdef CONFIG_MEMORY_HOTPLUG
692int arch_add_memory(int nid, u64 start, u64 size,
693		    struct mhp_params *params)
694{
695	unsigned long start_pfn = start >> PAGE_SHIFT;
696	unsigned long nr_pages = size >> PAGE_SHIFT;
697	int ret;
698
699	if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot))
700		return -EINVAL;
701
702	ret = __add_pages(nid, start_pfn, nr_pages, params);
703	if (ret)
704		printk("%s: Problem encountered in __add_pages() as ret=%d\n",
705		       __func__,  ret);
706
707	return ret;
708}
709
710void arch_remove_memory(int nid, u64 start, u64 size,
711			struct vmem_altmap *altmap)
712{
713	unsigned long start_pfn = start >> PAGE_SHIFT;
714	unsigned long nr_pages = size >> PAGE_SHIFT;
715
716	__remove_pages(start_pfn, nr_pages, altmap);
717}
718#endif