xref: /openbmc/linux/arch/ia64/mm/init.c (revision ac8b6f14)
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/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 = vm_area_alloc(current->mm);
117 	if (vma) {
118 		vma_set_anonymous(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_set_anonymous(vma);
137 			vma->vm_end = PAGE_SIZE;
138 			vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
139 			vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
140 					VM_DONTEXPAND | VM_DONTDUMP;
141 			down_write(&current->mm->mmap_sem);
142 			if (insert_vm_struct(current->mm, vma)) {
143 				up_write(&current->mm->mmap_sem);
144 				vm_area_free(vma);
145 				return;
146 			}
147 			up_write(&current->mm->mmap_sem);
148 		}
149 	}
150 }
151 
152 void
153 free_initmem (void)
154 {
155 	free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
156 			   -1, "unused kernel");
157 }
158 
159 void __init
160 free_initrd_mem (unsigned long start, unsigned long end)
161 {
162 	/*
163 	 * EFI uses 4KB pages while the kernel can use 4KB or bigger.
164 	 * Thus EFI and the kernel may have different page sizes. It is
165 	 * therefore possible to have the initrd share the same page as
166 	 * the end of the kernel (given current setup).
167 	 *
168 	 * To avoid freeing/using the wrong page (kernel sized) we:
169 	 *	- align up the beginning of initrd
170 	 *	- align down the end of initrd
171 	 *
172 	 *  |             |
173 	 *  |=============| a000
174 	 *  |             |
175 	 *  |             |
176 	 *  |             | 9000
177 	 *  |/////////////|
178 	 *  |/////////////|
179 	 *  |=============| 8000
180 	 *  |///INITRD////|
181 	 *  |/////////////|
182 	 *  |/////////////| 7000
183 	 *  |             |
184 	 *  |KKKKKKKKKKKKK|
185 	 *  |=============| 6000
186 	 *  |KKKKKKKKKKKKK|
187 	 *  |KKKKKKKKKKKKK|
188 	 *  K=kernel using 8KB pages
189 	 *
190 	 * In this example, we must free page 8000 ONLY. So we must align up
191 	 * initrd_start and keep initrd_end as is.
192 	 */
193 	start = PAGE_ALIGN(start);
194 	end = end & PAGE_MASK;
195 
196 	if (start < end)
197 		printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);
198 
199 	for (; start < end; start += PAGE_SIZE) {
200 		if (!virt_addr_valid(start))
201 			continue;
202 		free_reserved_page(virt_to_page(start));
203 	}
204 }
205 
206 /*
207  * This installs a clean page in the kernel's page table.
208  */
209 static struct page * __init
210 put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
211 {
212 	pgd_t *pgd;
213 	pud_t *pud;
214 	pmd_t *pmd;
215 	pte_t *pte;
216 
217 	pgd = pgd_offset_k(address);		/* note: this is NOT pgd_offset()! */
218 
219 	{
220 		pud = pud_alloc(&init_mm, pgd, address);
221 		if (!pud)
222 			goto out;
223 		pmd = pmd_alloc(&init_mm, pud, address);
224 		if (!pmd)
225 			goto out;
226 		pte = pte_alloc_kernel(pmd, address);
227 		if (!pte)
228 			goto out;
229 		if (!pte_none(*pte))
230 			goto out;
231 		set_pte(pte, mk_pte(page, pgprot));
232 	}
233   out:
234 	/* no need for flush_tlb */
235 	return page;
236 }
237 
238 static void __init
239 setup_gate (void)
240 {
241 	struct page *page;
242 
243 	/*
244 	 * Map the gate page twice: once read-only to export the ELF
245 	 * headers etc. and once execute-only page to enable
246 	 * privilege-promotion via "epc":
247 	 */
248 	page = virt_to_page(ia64_imva(__start_gate_section));
249 	put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
250 #ifdef HAVE_BUGGY_SEGREL
251 	page = virt_to_page(ia64_imva(__start_gate_section + PAGE_SIZE));
252 	put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
253 #else
254 	put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
255 	/* Fill in the holes (if any) with read-only zero pages: */
256 	{
257 		unsigned long addr;
258 
259 		for (addr = GATE_ADDR + PAGE_SIZE;
260 		     addr < GATE_ADDR + PERCPU_PAGE_SIZE;
261 		     addr += PAGE_SIZE)
262 		{
263 			put_kernel_page(ZERO_PAGE(0), addr,
264 					PAGE_READONLY);
265 			put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
266 					PAGE_READONLY);
267 		}
268 	}
269 #endif
270 	ia64_patch_gate();
271 }
272 
273 static struct vm_area_struct gate_vma;
274 
275 static int __init gate_vma_init(void)
276 {
277 	vma_init(&gate_vma, NULL);
278 	gate_vma.vm_start = FIXADDR_USER_START;
279 	gate_vma.vm_end = FIXADDR_USER_END;
280 	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
281 	gate_vma.vm_page_prot = __P101;
282 
283 	return 0;
284 }
285 __initcall(gate_vma_init);
286 
287 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
288 {
289 	return &gate_vma;
290 }
291 
292 int in_gate_area_no_mm(unsigned long addr)
293 {
294 	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
295 		return 1;
296 	return 0;
297 }
298 
299 int in_gate_area(struct mm_struct *mm, unsigned long addr)
300 {
301 	return in_gate_area_no_mm(addr);
302 }
303 
304 void ia64_mmu_init(void *my_cpu_data)
305 {
306 	unsigned long pta, impl_va_bits;
307 	extern void tlb_init(void);
308 
309 #ifdef CONFIG_DISABLE_VHPT
310 #	define VHPT_ENABLE_BIT	0
311 #else
312 #	define VHPT_ENABLE_BIT	1
313 #endif
314 
315 	/*
316 	 * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
317 	 * address space.  The IA-64 architecture guarantees that at least 50 bits of
318 	 * virtual address space are implemented but if we pick a large enough page size
319 	 * (e.g., 64KB), the mapped address space is big enough that it will overlap with
320 	 * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
321 	 * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
322 	 * problem in practice.  Alternatively, we could truncate the top of the mapped
323 	 * address space to not permit mappings that would overlap with the VMLPT.
324 	 * --davidm 00/12/06
325 	 */
326 #	define pte_bits			3
327 #	define mapped_space_bits	(3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
328 	/*
329 	 * The virtual page table has to cover the entire implemented address space within
330 	 * a region even though not all of this space may be mappable.  The reason for
331 	 * this is that the Access bit and Dirty bit fault handlers perform
332 	 * non-speculative accesses to the virtual page table, so the address range of the
333 	 * virtual page table itself needs to be covered by virtual page table.
334 	 */
335 #	define vmlpt_bits		(impl_va_bits - PAGE_SHIFT + pte_bits)
336 #	define POW2(n)			(1ULL << (n))
337 
338 	impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));
339 
340 	if (impl_va_bits < 51 || impl_va_bits > 61)
341 		panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
342 	/*
343 	 * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
344 	 * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
345 	 * the test makes sure that our mapped space doesn't overlap the
346 	 * unimplemented hole in the middle of the region.
347 	 */
348 	if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
349 	    (mapped_space_bits > impl_va_bits - 1))
350 		panic("Cannot build a big enough virtual-linear page table"
351 		      " to cover mapped address space.\n"
352 		      " Try using a smaller page size.\n");
353 
354 
355 	/* place the VMLPT at the end of each page-table mapped region: */
356 	pta = POW2(61) - POW2(vmlpt_bits);
357 
358 	/*
359 	 * Set the (virtually mapped linear) page table address.  Bit
360 	 * 8 selects between the short and long format, bits 2-7 the
361 	 * size of the table, and bit 0 whether the VHPT walker is
362 	 * enabled.
363 	 */
364 	ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);
365 
366 	ia64_tlb_init();
367 
368 #ifdef	CONFIG_HUGETLB_PAGE
369 	ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
370 	ia64_srlz_d();
371 #endif
372 }
373 
374 #ifdef CONFIG_VIRTUAL_MEM_MAP
375 int vmemmap_find_next_valid_pfn(int node, int i)
376 {
377 	unsigned long end_address, hole_next_pfn;
378 	unsigned long stop_address;
379 	pg_data_t *pgdat = NODE_DATA(node);
380 
381 	end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
382 	end_address = PAGE_ALIGN(end_address);
383 	stop_address = (unsigned long) &vmem_map[pgdat_end_pfn(pgdat)];
384 
385 	do {
386 		pgd_t *pgd;
387 		pud_t *pud;
388 		pmd_t *pmd;
389 		pte_t *pte;
390 
391 		pgd = pgd_offset_k(end_address);
392 		if (pgd_none(*pgd)) {
393 			end_address += PGDIR_SIZE;
394 			continue;
395 		}
396 
397 		pud = pud_offset(pgd, end_address);
398 		if (pud_none(*pud)) {
399 			end_address += PUD_SIZE;
400 			continue;
401 		}
402 
403 		pmd = pmd_offset(pud, end_address);
404 		if (pmd_none(*pmd)) {
405 			end_address += PMD_SIZE;
406 			continue;
407 		}
408 
409 		pte = pte_offset_kernel(pmd, end_address);
410 retry_pte:
411 		if (pte_none(*pte)) {
412 			end_address += PAGE_SIZE;
413 			pte++;
414 			if ((end_address < stop_address) &&
415 			    (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
416 				goto retry_pte;
417 			continue;
418 		}
419 		/* Found next valid vmem_map page */
420 		break;
421 	} while (end_address < stop_address);
422 
423 	end_address = min(end_address, stop_address);
424 	end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
425 	hole_next_pfn = end_address / sizeof(struct page);
426 	return hole_next_pfn - pgdat->node_start_pfn;
427 }
428 
429 int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
430 {
431 	unsigned long address, start_page, end_page;
432 	struct page *map_start, *map_end;
433 	int node;
434 	pgd_t *pgd;
435 	pud_t *pud;
436 	pmd_t *pmd;
437 	pte_t *pte;
438 
439 	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
440 	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
441 
442 	start_page = (unsigned long) map_start & PAGE_MASK;
443 	end_page = PAGE_ALIGN((unsigned long) map_end);
444 	node = paddr_to_nid(__pa(start));
445 
446 	for (address = start_page; address < end_page; address += PAGE_SIZE) {
447 		pgd = pgd_offset_k(address);
448 		if (pgd_none(*pgd))
449 			pgd_populate(&init_mm, pgd, memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node));
450 		pud = pud_offset(pgd, address);
451 
452 		if (pud_none(*pud))
453 			pud_populate(&init_mm, pud, memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node));
454 		pmd = pmd_offset(pud, address);
455 
456 		if (pmd_none(*pmd))
457 			pmd_populate_kernel(&init_mm, pmd, memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node));
458 		pte = pte_offset_kernel(pmd, address);
459 
460 		if (pte_none(*pte))
461 			set_pte(pte, pfn_pte(__pa(memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node)) >> PAGE_SHIFT,
462 					     PAGE_KERNEL));
463 	}
464 	return 0;
465 }
466 
467 struct memmap_init_callback_data {
468 	struct page *start;
469 	struct page *end;
470 	int nid;
471 	unsigned long zone;
472 };
473 
474 static int __meminit
475 virtual_memmap_init(u64 start, u64 end, void *arg)
476 {
477 	struct memmap_init_callback_data *args;
478 	struct page *map_start, *map_end;
479 
480 	args = (struct memmap_init_callback_data *) arg;
481 	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
482 	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
483 
484 	if (map_start < args->start)
485 		map_start = args->start;
486 	if (map_end > args->end)
487 		map_end = args->end;
488 
489 	/*
490 	 * We have to initialize "out of bounds" struct page elements that fit completely
491 	 * on the same pages that were allocated for the "in bounds" elements because they
492 	 * may be referenced later (and found to be "reserved").
493 	 */
494 	map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
495 	map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
496 		    / sizeof(struct page));
497 
498 	if (map_start < map_end)
499 		memmap_init_zone((unsigned long)(map_end - map_start),
500 				 args->nid, args->zone, page_to_pfn(map_start),
501 				 MEMMAP_EARLY, NULL);
502 	return 0;
503 }
504 
505 void __meminit
506 memmap_init (unsigned long size, int nid, unsigned long zone,
507 	     unsigned long start_pfn)
508 {
509 	if (!vmem_map) {
510 		memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY,
511 				NULL);
512 	} else {
513 		struct page *start;
514 		struct memmap_init_callback_data args;
515 
516 		start = pfn_to_page(start_pfn);
517 		args.start = start;
518 		args.end = start + size;
519 		args.nid = nid;
520 		args.zone = zone;
521 
522 		efi_memmap_walk(virtual_memmap_init, &args);
523 	}
524 }
525 
526 int
527 ia64_pfn_valid (unsigned long pfn)
528 {
529 	char byte;
530 	struct page *pg = pfn_to_page(pfn);
531 
532 	return     (__get_user(byte, (char __user *) pg) == 0)
533 		&& ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
534 			|| (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
535 }
536 EXPORT_SYMBOL(ia64_pfn_valid);
537 
538 int __init find_largest_hole(u64 start, u64 end, void *arg)
539 {
540 	u64 *max_gap = arg;
541 
542 	static u64 last_end = PAGE_OFFSET;
543 
544 	/* NOTE: this algorithm assumes efi memmap table is ordered */
545 
546 	if (*max_gap < (start - last_end))
547 		*max_gap = start - last_end;
548 	last_end = end;
549 	return 0;
550 }
551 
552 #endif /* CONFIG_VIRTUAL_MEM_MAP */
553 
554 int __init register_active_ranges(u64 start, u64 len, int nid)
555 {
556 	u64 end = start + len;
557 
558 #ifdef CONFIG_KEXEC
559 	if (start > crashk_res.start && start < crashk_res.end)
560 		start = crashk_res.end;
561 	if (end > crashk_res.start && end < crashk_res.end)
562 		end = crashk_res.start;
563 #endif
564 
565 	if (start < end)
566 		memblock_add_node(__pa(start), end - start, nid);
567 	return 0;
568 }
569 
570 int
571 find_max_min_low_pfn (u64 start, u64 end, void *arg)
572 {
573 	unsigned long pfn_start, pfn_end;
574 #ifdef CONFIG_FLATMEM
575 	pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
576 	pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
577 #else
578 	pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
579 	pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
580 #endif
581 	min_low_pfn = min(min_low_pfn, pfn_start);
582 	max_low_pfn = max(max_low_pfn, pfn_end);
583 	return 0;
584 }
585 
586 /*
587  * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
588  * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
589  * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
590  * useful for performance testing, but conceivably could also come in handy for debugging
591  * purposes.
592  */
593 
594 static int nolwsys __initdata;
595 
596 static int __init
597 nolwsys_setup (char *s)
598 {
599 	nolwsys = 1;
600 	return 1;
601 }
602 
603 __setup("nolwsys", nolwsys_setup);
604 
605 void __init
606 mem_init (void)
607 {
608 	int i;
609 
610 	BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
611 	BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
612 	BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
613 
614 #ifdef CONFIG_PCI
615 	/*
616 	 * This needs to be called _after_ the command line has been parsed but _before_
617 	 * any drivers that may need the PCI DMA interface are initialized or bootmem has
618 	 * been freed.
619 	 */
620 	platform_dma_init();
621 #endif
622 
623 #ifdef CONFIG_FLATMEM
624 	BUG_ON(!mem_map);
625 #endif
626 
627 	set_max_mapnr(max_low_pfn);
628 	high_memory = __va(max_low_pfn * PAGE_SIZE);
629 	memblock_free_all();
630 	mem_init_print_info(NULL);
631 
632 	/*
633 	 * For fsyscall entrpoints with no light-weight handler, use the ordinary
634 	 * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
635 	 * code can tell them apart.
636 	 */
637 	for (i = 0; i < NR_syscalls; ++i) {
638 		extern unsigned long fsyscall_table[NR_syscalls];
639 		extern unsigned long sys_call_table[NR_syscalls];
640 
641 		if (!fsyscall_table[i] || nolwsys)
642 			fsyscall_table[i] = sys_call_table[i] | 1;
643 	}
644 	setup_gate();
645 }
646 
647 #ifdef CONFIG_MEMORY_HOTPLUG
648 int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap,
649 		bool want_memblock)
650 {
651 	unsigned long start_pfn = start >> PAGE_SHIFT;
652 	unsigned long nr_pages = size >> PAGE_SHIFT;
653 	int ret;
654 
655 	ret = __add_pages(nid, start_pfn, nr_pages, altmap, want_memblock);
656 	if (ret)
657 		printk("%s: Problem encountered in __add_pages() as ret=%d\n",
658 		       __func__,  ret);
659 
660 	return ret;
661 }
662 
663 #ifdef CONFIG_MEMORY_HOTREMOVE
664 int arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
665 {
666 	unsigned long start_pfn = start >> PAGE_SHIFT;
667 	unsigned long nr_pages = size >> PAGE_SHIFT;
668 	struct zone *zone;
669 	int ret;
670 
671 	zone = page_zone(pfn_to_page(start_pfn));
672 	ret = __remove_pages(zone, start_pfn, nr_pages, altmap);
673 	if (ret)
674 		pr_warn("%s: Problem encountered in __remove_pages() as"
675 			" ret=%d\n", __func__,  ret);
676 
677 	return ret;
678 }
679 #endif
680 #endif
681