xref: /openbmc/linux/arch/ia64/mm/init.c (revision 7b73a9c8)
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 
41 extern void ia64_tlb_init (void);
42 
43 unsigned long MAX_DMA_ADDRESS = PAGE_OFFSET + 0x100000000UL;
44 
45 #ifdef CONFIG_VIRTUAL_MEM_MAP
46 unsigned long VMALLOC_END = VMALLOC_END_INIT;
47 EXPORT_SYMBOL(VMALLOC_END);
48 struct page *vmem_map;
49 EXPORT_SYMBOL(vmem_map);
50 #endif
51 
52 struct page *zero_page_memmap_ptr;	/* map entry for zero page */
53 EXPORT_SYMBOL(zero_page_memmap_ptr);
54 
55 void
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  */
76 void 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 
86 inline void
87 ia64_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  */
102 void
103 ia64_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 		down_write(&current->mm->mmap_sem);
122 		if (insert_vm_struct(current->mm, vma)) {
123 			up_write(&current->mm->mmap_sem);
124 			vm_area_free(vma);
125 			return;
126 		}
127 		up_write(&current->mm->mmap_sem);
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 			down_write(&current->mm->mmap_sem);
140 			if (insert_vm_struct(current->mm, vma)) {
141 				up_write(&current->mm->mmap_sem);
142 				vm_area_free(vma);
143 				return;
144 			}
145 			up_write(&current->mm->mmap_sem);
146 		}
147 	}
148 }
149 
150 void
151 free_initmem (void)
152 {
153 	free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
154 			   -1, "unused kernel");
155 }
156 
157 void __init
158 free_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  */
207 static struct page * __init
208 put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
209 {
210 	pgd_t *pgd;
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 		pud = pud_alloc(&init_mm, pgd, address);
219 		if (!pud)
220 			goto out;
221 		pmd = pmd_alloc(&init_mm, pud, address);
222 		if (!pmd)
223 			goto out;
224 		pte = pte_alloc_kernel(pmd, address);
225 		if (!pte)
226 			goto out;
227 		if (!pte_none(*pte))
228 			goto out;
229 		set_pte(pte, mk_pte(page, pgprot));
230 	}
231   out:
232 	/* no need for flush_tlb */
233 	return page;
234 }
235 
236 static void __init
237 setup_gate (void)
238 {
239 	struct page *page;
240 
241 	/*
242 	 * Map the gate page twice: once read-only to export the ELF
243 	 * headers etc. and once execute-only page to enable
244 	 * privilege-promotion via "epc":
245 	 */
246 	page = virt_to_page(ia64_imva(__start_gate_section));
247 	put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
248 #ifdef HAVE_BUGGY_SEGREL
249 	page = virt_to_page(ia64_imva(__start_gate_section + PAGE_SIZE));
250 	put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
251 #else
252 	put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
253 	/* Fill in the holes (if any) with read-only zero pages: */
254 	{
255 		unsigned long addr;
256 
257 		for (addr = GATE_ADDR + PAGE_SIZE;
258 		     addr < GATE_ADDR + PERCPU_PAGE_SIZE;
259 		     addr += PAGE_SIZE)
260 		{
261 			put_kernel_page(ZERO_PAGE(0), addr,
262 					PAGE_READONLY);
263 			put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
264 					PAGE_READONLY);
265 		}
266 	}
267 #endif
268 	ia64_patch_gate();
269 }
270 
271 static struct vm_area_struct gate_vma;
272 
273 static int __init gate_vma_init(void)
274 {
275 	vma_init(&gate_vma, NULL);
276 	gate_vma.vm_start = FIXADDR_USER_START;
277 	gate_vma.vm_end = FIXADDR_USER_END;
278 	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
279 	gate_vma.vm_page_prot = __P101;
280 
281 	return 0;
282 }
283 __initcall(gate_vma_init);
284 
285 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
286 {
287 	return &gate_vma;
288 }
289 
290 int in_gate_area_no_mm(unsigned long addr)
291 {
292 	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
293 		return 1;
294 	return 0;
295 }
296 
297 int in_gate_area(struct mm_struct *mm, unsigned long addr)
298 {
299 	return in_gate_area_no_mm(addr);
300 }
301 
302 void ia64_mmu_init(void *my_cpu_data)
303 {
304 	unsigned long pta, impl_va_bits;
305 	extern void tlb_init(void);
306 
307 #ifdef CONFIG_DISABLE_VHPT
308 #	define VHPT_ENABLE_BIT	0
309 #else
310 #	define VHPT_ENABLE_BIT	1
311 #endif
312 
313 	/*
314 	 * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
315 	 * address space.  The IA-64 architecture guarantees that at least 50 bits of
316 	 * virtual address space are implemented but if we pick a large enough page size
317 	 * (e.g., 64KB), the mapped address space is big enough that it will overlap with
318 	 * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
319 	 * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
320 	 * problem in practice.  Alternatively, we could truncate the top of the mapped
321 	 * address space to not permit mappings that would overlap with the VMLPT.
322 	 * --davidm 00/12/06
323 	 */
324 #	define pte_bits			3
325 #	define mapped_space_bits	(3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
326 	/*
327 	 * The virtual page table has to cover the entire implemented address space within
328 	 * a region even though not all of this space may be mappable.  The reason for
329 	 * this is that the Access bit and Dirty bit fault handlers perform
330 	 * non-speculative accesses to the virtual page table, so the address range of the
331 	 * virtual page table itself needs to be covered by virtual page table.
332 	 */
333 #	define vmlpt_bits		(impl_va_bits - PAGE_SHIFT + pte_bits)
334 #	define POW2(n)			(1ULL << (n))
335 
336 	impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));
337 
338 	if (impl_va_bits < 51 || impl_va_bits > 61)
339 		panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
340 	/*
341 	 * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
342 	 * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
343 	 * the test makes sure that our mapped space doesn't overlap the
344 	 * unimplemented hole in the middle of the region.
345 	 */
346 	if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
347 	    (mapped_space_bits > impl_va_bits - 1))
348 		panic("Cannot build a big enough virtual-linear page table"
349 		      " to cover mapped address space.\n"
350 		      " Try using a smaller page size.\n");
351 
352 
353 	/* place the VMLPT at the end of each page-table mapped region: */
354 	pta = POW2(61) - POW2(vmlpt_bits);
355 
356 	/*
357 	 * Set the (virtually mapped linear) page table address.  Bit
358 	 * 8 selects between the short and long format, bits 2-7 the
359 	 * size of the table, and bit 0 whether the VHPT walker is
360 	 * enabled.
361 	 */
362 	ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);
363 
364 	ia64_tlb_init();
365 
366 #ifdef	CONFIG_HUGETLB_PAGE
367 	ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
368 	ia64_srlz_d();
369 #endif
370 }
371 
372 #ifdef CONFIG_VIRTUAL_MEM_MAP
373 int vmemmap_find_next_valid_pfn(int node, int i)
374 {
375 	unsigned long end_address, hole_next_pfn;
376 	unsigned long stop_address;
377 	pg_data_t *pgdat = NODE_DATA(node);
378 
379 	end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
380 	end_address = PAGE_ALIGN(end_address);
381 	stop_address = (unsigned long) &vmem_map[pgdat_end_pfn(pgdat)];
382 
383 	do {
384 		pgd_t *pgd;
385 		pud_t *pud;
386 		pmd_t *pmd;
387 		pte_t *pte;
388 
389 		pgd = pgd_offset_k(end_address);
390 		if (pgd_none(*pgd)) {
391 			end_address += PGDIR_SIZE;
392 			continue;
393 		}
394 
395 		pud = pud_offset(pgd, end_address);
396 		if (pud_none(*pud)) {
397 			end_address += PUD_SIZE;
398 			continue;
399 		}
400 
401 		pmd = pmd_offset(pud, end_address);
402 		if (pmd_none(*pmd)) {
403 			end_address += PMD_SIZE;
404 			continue;
405 		}
406 
407 		pte = pte_offset_kernel(pmd, end_address);
408 retry_pte:
409 		if (pte_none(*pte)) {
410 			end_address += PAGE_SIZE;
411 			pte++;
412 			if ((end_address < stop_address) &&
413 			    (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
414 				goto retry_pte;
415 			continue;
416 		}
417 		/* Found next valid vmem_map page */
418 		break;
419 	} while (end_address < stop_address);
420 
421 	end_address = min(end_address, stop_address);
422 	end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
423 	hole_next_pfn = end_address / sizeof(struct page);
424 	return hole_next_pfn - pgdat->node_start_pfn;
425 }
426 
427 int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
428 {
429 	unsigned long address, start_page, end_page;
430 	struct page *map_start, *map_end;
431 	int node;
432 	pgd_t *pgd;
433 	pud_t *pud;
434 	pmd_t *pmd;
435 	pte_t *pte;
436 
437 	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
438 	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
439 
440 	start_page = (unsigned long) map_start & PAGE_MASK;
441 	end_page = PAGE_ALIGN((unsigned long) map_end);
442 	node = paddr_to_nid(__pa(start));
443 
444 	for (address = start_page; address < end_page; address += PAGE_SIZE) {
445 		pgd = pgd_offset_k(address);
446 		if (pgd_none(*pgd)) {
447 			pud = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
448 			if (!pud)
449 				goto err_alloc;
450 			pgd_populate(&init_mm, pgd, pud);
451 		}
452 		pud = pud_offset(pgd, address);
453 
454 		if (pud_none(*pud)) {
455 			pmd = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
456 			if (!pmd)
457 				goto err_alloc;
458 			pud_populate(&init_mm, pud, pmd);
459 		}
460 		pmd = pmd_offset(pud, address);
461 
462 		if (pmd_none(*pmd)) {
463 			pte = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
464 			if (!pte)
465 				goto err_alloc;
466 			pmd_populate_kernel(&init_mm, pmd, pte);
467 		}
468 		pte = pte_offset_kernel(pmd, address);
469 
470 		if (pte_none(*pte)) {
471 			void *page = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE,
472 							 node);
473 			if (!page)
474 				goto err_alloc;
475 			set_pte(pte, pfn_pte(__pa(page) >> PAGE_SHIFT,
476 					     PAGE_KERNEL));
477 		}
478 	}
479 	return 0;
480 
481 err_alloc:
482 	panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d\n",
483 	      __func__, PAGE_SIZE, PAGE_SIZE, node);
484 	return -ENOMEM;
485 }
486 
487 struct memmap_init_callback_data {
488 	struct page *start;
489 	struct page *end;
490 	int nid;
491 	unsigned long zone;
492 };
493 
494 static int __meminit
495 virtual_memmap_init(u64 start, u64 end, void *arg)
496 {
497 	struct memmap_init_callback_data *args;
498 	struct page *map_start, *map_end;
499 
500 	args = (struct memmap_init_callback_data *) arg;
501 	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
502 	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
503 
504 	if (map_start < args->start)
505 		map_start = args->start;
506 	if (map_end > args->end)
507 		map_end = args->end;
508 
509 	/*
510 	 * We have to initialize "out of bounds" struct page elements that fit completely
511 	 * on the same pages that were allocated for the "in bounds" elements because they
512 	 * may be referenced later (and found to be "reserved").
513 	 */
514 	map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
515 	map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
516 		    / sizeof(struct page));
517 
518 	if (map_start < map_end)
519 		memmap_init_zone((unsigned long)(map_end - map_start),
520 				 args->nid, args->zone, page_to_pfn(map_start),
521 				 MEMMAP_EARLY, NULL);
522 	return 0;
523 }
524 
525 void __meminit
526 memmap_init (unsigned long size, int nid, unsigned long zone,
527 	     unsigned long start_pfn)
528 {
529 	if (!vmem_map) {
530 		memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY,
531 				NULL);
532 	} else {
533 		struct page *start;
534 		struct memmap_init_callback_data args;
535 
536 		start = pfn_to_page(start_pfn);
537 		args.start = start;
538 		args.end = start + size;
539 		args.nid = nid;
540 		args.zone = zone;
541 
542 		efi_memmap_walk(virtual_memmap_init, &args);
543 	}
544 }
545 
546 int
547 ia64_pfn_valid (unsigned long pfn)
548 {
549 	char byte;
550 	struct page *pg = pfn_to_page(pfn);
551 
552 	return     (__get_user(byte, (char __user *) pg) == 0)
553 		&& ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
554 			|| (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
555 }
556 EXPORT_SYMBOL(ia64_pfn_valid);
557 
558 int __init find_largest_hole(u64 start, u64 end, void *arg)
559 {
560 	u64 *max_gap = arg;
561 
562 	static u64 last_end = PAGE_OFFSET;
563 
564 	/* NOTE: this algorithm assumes efi memmap table is ordered */
565 
566 	if (*max_gap < (start - last_end))
567 		*max_gap = start - last_end;
568 	last_end = end;
569 	return 0;
570 }
571 
572 #endif /* CONFIG_VIRTUAL_MEM_MAP */
573 
574 int __init register_active_ranges(u64 start, u64 len, int nid)
575 {
576 	u64 end = start + len;
577 
578 #ifdef CONFIG_KEXEC
579 	if (start > crashk_res.start && start < crashk_res.end)
580 		start = crashk_res.end;
581 	if (end > crashk_res.start && end < crashk_res.end)
582 		end = crashk_res.start;
583 #endif
584 
585 	if (start < end)
586 		memblock_add_node(__pa(start), end - start, nid);
587 	return 0;
588 }
589 
590 int
591 find_max_min_low_pfn (u64 start, u64 end, void *arg)
592 {
593 	unsigned long pfn_start, pfn_end;
594 #ifdef CONFIG_FLATMEM
595 	pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
596 	pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
597 #else
598 	pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
599 	pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
600 #endif
601 	min_low_pfn = min(min_low_pfn, pfn_start);
602 	max_low_pfn = max(max_low_pfn, pfn_end);
603 	return 0;
604 }
605 
606 /*
607  * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
608  * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
609  * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
610  * useful for performance testing, but conceivably could also come in handy for debugging
611  * purposes.
612  */
613 
614 static int nolwsys __initdata;
615 
616 static int __init
617 nolwsys_setup (char *s)
618 {
619 	nolwsys = 1;
620 	return 1;
621 }
622 
623 __setup("nolwsys", nolwsys_setup);
624 
625 void __init
626 mem_init (void)
627 {
628 	int i;
629 
630 	BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
631 	BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
632 	BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
633 
634 	/*
635 	 * This needs to be called _after_ the command line has been parsed but
636 	 * _before_ any drivers that may need the PCI DMA interface are
637 	 * initialized or bootmem has been freed.
638 	 */
639 #ifdef CONFIG_INTEL_IOMMU
640 	detect_intel_iommu();
641 	if (!iommu_detected)
642 #endif
643 #ifdef CONFIG_SWIOTLB
644 		swiotlb_init(1);
645 #endif
646 
647 #ifdef CONFIG_FLATMEM
648 	BUG_ON(!mem_map);
649 #endif
650 
651 	set_max_mapnr(max_low_pfn);
652 	high_memory = __va(max_low_pfn * PAGE_SIZE);
653 	memblock_free_all();
654 	mem_init_print_info(NULL);
655 
656 	/*
657 	 * For fsyscall entrpoints with no light-weight handler, use the ordinary
658 	 * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
659 	 * code can tell them apart.
660 	 */
661 	for (i = 0; i < NR_syscalls; ++i) {
662 		extern unsigned long fsyscall_table[NR_syscalls];
663 		extern unsigned long sys_call_table[NR_syscalls];
664 
665 		if (!fsyscall_table[i] || nolwsys)
666 			fsyscall_table[i] = sys_call_table[i] | 1;
667 	}
668 	setup_gate();
669 }
670 
671 #ifdef CONFIG_MEMORY_HOTPLUG
672 int arch_add_memory(int nid, u64 start, u64 size,
673 			struct mhp_restrictions *restrictions)
674 {
675 	unsigned long start_pfn = start >> PAGE_SHIFT;
676 	unsigned long nr_pages = size >> PAGE_SHIFT;
677 	int ret;
678 
679 	ret = __add_pages(nid, start_pfn, nr_pages, restrictions);
680 	if (ret)
681 		printk("%s: Problem encountered in __add_pages() as ret=%d\n",
682 		       __func__,  ret);
683 
684 	return ret;
685 }
686 
687 void arch_remove_memory(int nid, u64 start, u64 size,
688 			struct vmem_altmap *altmap)
689 {
690 	unsigned long start_pfn = start >> PAGE_SHIFT;
691 	unsigned long nr_pages = size >> PAGE_SHIFT;
692 
693 	__remove_pages(start_pfn, nr_pages, altmap);
694 }
695 #endif
696