init_32.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *
  4 *  Copyright (C) 1995  Linus Torvalds
  5 *
  6 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
  7 */
  8
  9#include <linux/signal.h>
 10#include <linux/sched.h>
 11#include <linux/kernel.h>
 12#include <linux/errno.h>
 13#include <linux/string.h>
 14#include <linux/types.h>
 15#include <linux/ptrace.h>
 16#include <linux/mman.h>
 17#include <linux/mm.h>
 18#include <linux/hugetlb.h>
 19#include <linux/swap.h>
 20#include <linux/smp.h>
 21#include <linux/init.h>
 22#include <linux/highmem.h>
 23#include <linux/pagemap.h>
 24#include <linux/pci.h>
 25#include <linux/pfn.h>
 26#include <linux/poison.h>
 27#include <linux/memblock.h>
 28#include <linux/proc_fs.h>
 29#include <linux/memory_hotplug.h>
 30#include <linux/initrd.h>
 31#include <linux/cpumask.h>
 32#include <linux/gfp.h>
 33
 34#include <asm/asm.h>
 35#include <asm/bios_ebda.h>
 36#include <asm/processor.h>
 37#include <linux/uaccess.h>
 38#include <asm/dma.h>
 39#include <asm/fixmap.h>
 40#include <asm/e820/api.h>
 41#include <asm/apic.h>
 42#include <asm/bugs.h>
 43#include <asm/tlb.h>
 44#include <asm/tlbflush.h>
 45#include <asm/olpc_ofw.h>
 46#include <asm/pgalloc.h>
 47#include <asm/sections.h>
 48#include <asm/setup.h>
 49#include <asm/set_memory.h>
 50#include <asm/page_types.h>
 51#include <asm/cpu_entry_area.h>
 52#include <asm/init.h>
 53#include <asm/pgtable_areas.h>
 54#include <asm/numa.h>
 55
 56#include "mm_internal.h"
 57
 58unsigned long highstart_pfn, highend_pfn;
 59
 60bool __read_mostly __vmalloc_start_set = false;
 61
 62/*
 63 * Creates a middle page table and puts a pointer to it in the
 64 * given global directory entry. This only returns the gd entry
 65 * in non-PAE compilation mode, since the middle layer is folded.
 66 */
 67static pmd_t * __init one_md_table_init(pgd_t *pgd)
 68{
 69	p4d_t *p4d;
 70	pud_t *pud;
 71	pmd_t *pmd_table;
 72
 73#ifdef CONFIG_X86_PAE
 74	if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
 75		pmd_table = (pmd_t *)alloc_low_page();
 76		set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
 77		p4d = p4d_offset(pgd, 0);
 78		pud = pud_offset(p4d, 0);
 79		BUG_ON(pmd_table != pmd_offset(pud, 0));
 80
 81		return pmd_table;
 82	}
 83#endif
 84	p4d = p4d_offset(pgd, 0);
 85	pud = pud_offset(p4d, 0);
 86	pmd_table = pmd_offset(pud, 0);
 87
 88	return pmd_table;
 89}
 90
 91/*
 92 * Create a page table and place a pointer to it in a middle page
 93 * directory entry:
 94 */
 95static pte_t * __init one_page_table_init(pmd_t *pmd)
 96{
 97	if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
 98		pte_t *page_table = (pte_t *)alloc_low_page();
 99
100		set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
101		BUG_ON(page_table != pte_offset_kernel(pmd, 0));
102	}
103
104	return pte_offset_kernel(pmd, 0);
105}
106
107pmd_t * __init populate_extra_pmd(unsigned long vaddr)
108{
109	int pgd_idx = pgd_index(vaddr);
110	int pmd_idx = pmd_index(vaddr);
111
112	return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx;
113}
114
115pte_t * __init populate_extra_pte(unsigned long vaddr)
116{
117	int pte_idx = pte_index(vaddr);
118	pmd_t *pmd;
119
120	pmd = populate_extra_pmd(vaddr);
121	return one_page_table_init(pmd) + pte_idx;
122}
123
124static unsigned long __init
125page_table_range_init_count(unsigned long start, unsigned long end)
126{
127	unsigned long count = 0;
128#ifdef CONFIG_HIGHMEM
129	int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
130	int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
131	int pgd_idx, pmd_idx;
132	unsigned long vaddr;
133
134	if (pmd_idx_kmap_begin == pmd_idx_kmap_end)
135		return 0;
136
137	vaddr = start;
138	pgd_idx = pgd_index(vaddr);
139	pmd_idx = pmd_index(vaddr);
140
141	for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) {
142		for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
143							pmd_idx++) {
144			if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin &&
145			    (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end)
146				count++;
147			vaddr += PMD_SIZE;
148		}
149		pmd_idx = 0;
150	}
151#endif
152	return count;
153}
154
155static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
156					   unsigned long vaddr, pte_t *lastpte,
157					   void **adr)
158{
159#ifdef CONFIG_HIGHMEM
160	/*
161	 * Something (early fixmap) may already have put a pte
162	 * page here, which causes the page table allocation
163	 * to become nonlinear. Attempt to fix it, and if it
164	 * is still nonlinear then we have to bug.
165	 */
166	int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
167	int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
168
169	if (pmd_idx_kmap_begin != pmd_idx_kmap_end
170	    && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
171	    && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) {
172		pte_t *newpte;
173		int i;
174
175		BUG_ON(after_bootmem);
176		newpte = *adr;
177		for (i = 0; i < PTRS_PER_PTE; i++)
178			set_pte(newpte + i, pte[i]);
179		*adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE);
180
181		set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
182		BUG_ON(newpte != pte_offset_kernel(pmd, 0));
183		__flush_tlb_all();
184
185		pte = newpte;
186	}
187	BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
188	       && vaddr > fix_to_virt(FIX_KMAP_END)
189	       && lastpte && lastpte + PTRS_PER_PTE != pte);
190#endif
191	return pte;
192}
193
194/*
195 * This function initializes a certain range of kernel virtual memory
196 * with new bootmem page tables, everywhere page tables are missing in
197 * the given range.
198 *
199 * NOTE: The pagetables are allocated contiguous on the physical space
200 * so we can cache the place of the first one and move around without
201 * checking the pgd every time.
202 */
203static void __init
204page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
205{
206	int pgd_idx, pmd_idx;
207	unsigned long vaddr;
208	pgd_t *pgd;
209	pmd_t *pmd;
210	pte_t *pte = NULL;
211	unsigned long count = page_table_range_init_count(start, end);
212	void *adr = NULL;
213
214	if (count)
215		adr = alloc_low_pages(count);
216
217	vaddr = start;
218	pgd_idx = pgd_index(vaddr);
219	pmd_idx = pmd_index(vaddr);
220	pgd = pgd_base + pgd_idx;
221
222	for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
223		pmd = one_md_table_init(pgd);
224		pmd = pmd + pmd_index(vaddr);
225		for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
226							pmd++, pmd_idx++) {
227			pte = page_table_kmap_check(one_page_table_init(pmd),
228						    pmd, vaddr, pte, &adr);
229
230			vaddr += PMD_SIZE;
231		}
232		pmd_idx = 0;
233	}
234}
235
236static inline int is_x86_32_kernel_text(unsigned long addr)
237{
238	if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end)
239		return 1;
240	return 0;
241}
242
243/*
244 * This maps the physical memory to kernel virtual address space, a total
245 * of max_low_pfn pages, by creating page tables starting from address
246 * PAGE_OFFSET:
247 */
248unsigned long __init
249kernel_physical_mapping_init(unsigned long start,
250			     unsigned long end,
251			     unsigned long page_size_mask,
252			     pgprot_t prot)
253{
254	int use_pse = page_size_mask == (1<<PG_LEVEL_2M);
255	unsigned long last_map_addr = end;
256	unsigned long start_pfn, end_pfn;
257	pgd_t *pgd_base = swapper_pg_dir;
258	int pgd_idx, pmd_idx, pte_ofs;
259	unsigned long pfn;
260	pgd_t *pgd;
261	pmd_t *pmd;
262	pte_t *pte;
263	unsigned pages_2m, pages_4k;
264	int mapping_iter;
265
266	start_pfn = start >> PAGE_SHIFT;
267	end_pfn = end >> PAGE_SHIFT;
268
269	/*
270	 * First iteration will setup identity mapping using large/small pages
271	 * based on use_pse, with other attributes same as set by
272	 * the early code in head_32.S
273	 *
274	 * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
275	 * as desired for the kernel identity mapping.
276	 *
277	 * This two pass mechanism conforms to the TLB app note which says:
278	 *
279	 *     "Software should not write to a paging-structure entry in a way
280	 *      that would change, for any linear address, both the page size
281	 *      and either the page frame or attributes."
282	 */
283	mapping_iter = 1;
284
285	if (!boot_cpu_has(X86_FEATURE_PSE))
286		use_pse = 0;
287
288repeat:
289	pages_2m = pages_4k = 0;
290	pfn = start_pfn;
291	pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
292	pgd = pgd_base + pgd_idx;
293	for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
294		pmd = one_md_table_init(pgd);
295
296		if (pfn >= end_pfn)
297			continue;
298#ifdef CONFIG_X86_PAE
299		pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
300		pmd += pmd_idx;
301#else
302		pmd_idx = 0;
303#endif
304		for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
305		     pmd++, pmd_idx++) {
306			unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
307
308			/*
309			 * Map with big pages if possible, otherwise
310			 * create normal page tables:
311			 */
312			if (use_pse) {
313				unsigned int addr2;
314				pgprot_t prot = PAGE_KERNEL_LARGE;
315				/*
316				 * first pass will use the same initial
317				 * identity mapping attribute + _PAGE_PSE.
318				 */
319				pgprot_t init_prot =
320					__pgprot(PTE_IDENT_ATTR |
321						 _PAGE_PSE);
322
323				pfn &= PMD_MASK >> PAGE_SHIFT;
324				addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
325					PAGE_OFFSET + PAGE_SIZE-1;
326
327				if (is_x86_32_kernel_text(addr) ||
328				    is_x86_32_kernel_text(addr2))
329					prot = PAGE_KERNEL_LARGE_EXEC;
330
331				pages_2m++;
332				if (mapping_iter == 1)
333					set_pmd(pmd, pfn_pmd(pfn, init_prot));
334				else
335					set_pmd(pmd, pfn_pmd(pfn, prot));
336
337				pfn += PTRS_PER_PTE;
338				continue;
339			}
340			pte = one_page_table_init(pmd);
341
342			pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
343			pte += pte_ofs;
344			for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
345			     pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
346				pgprot_t prot = PAGE_KERNEL;
347				/*
348				 * first pass will use the same initial
349				 * identity mapping attribute.
350				 */
351				pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
352
353				if (is_x86_32_kernel_text(addr))
354					prot = PAGE_KERNEL_EXEC;
355
356				pages_4k++;
357				if (mapping_iter == 1) {
358					set_pte(pte, pfn_pte(pfn, init_prot));
359					last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE;
360				} else
361					set_pte(pte, pfn_pte(pfn, prot));
362			}
363		}
364	}
365	if (mapping_iter == 1) {
366		/*
367		 * update direct mapping page count only in the first
368		 * iteration.
369		 */
370		update_page_count(PG_LEVEL_2M, pages_2m);
371		update_page_count(PG_LEVEL_4K, pages_4k);
372
373		/*
374		 * local global flush tlb, which will flush the previous
375		 * mappings present in both small and large page TLB's.
376		 */
377		__flush_tlb_all();
378
379		/*
380		 * Second iteration will set the actual desired PTE attributes.
381		 */
382		mapping_iter = 2;
383		goto repeat;
384	}
385	return last_map_addr;
386}
387
388#ifdef CONFIG_HIGHMEM
389static void __init permanent_kmaps_init(pgd_t *pgd_base)
390{
391	unsigned long vaddr = PKMAP_BASE;
392
393	page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
394
395	pkmap_page_table = virt_to_kpte(vaddr);
396}
397#else
398static inline void permanent_kmaps_init(pgd_t *pgd_base)
399{
400}
401#endif /* CONFIG_HIGHMEM */
402
403void __init sync_initial_page_table(void)
404{
405	clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY,
406			swapper_pg_dir     + KERNEL_PGD_BOUNDARY,
407			KERNEL_PGD_PTRS);
408
409	/*
410	 * sync back low identity map too.  It is used for example
411	 * in the 32-bit EFI stub.
412	 */
413	clone_pgd_range(initial_page_table,
414			swapper_pg_dir     + KERNEL_PGD_BOUNDARY,
415			min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
416}
417
418void __init native_pagetable_init(void)
419{
420	unsigned long pfn, va;
421	pgd_t *pgd, *base = swapper_pg_dir;
422	p4d_t *p4d;
423	pud_t *pud;
424	pmd_t *pmd;
425	pte_t *pte;
426
427	/*
428	 * Remove any mappings which extend past the end of physical
429	 * memory from the boot time page table.
430	 * In virtual address space, we should have at least two pages
431	 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END
432	 * definition. And max_low_pfn is set to VMALLOC_END physical
433	 * address. If initial memory mapping is doing right job, we
434	 * should have pte used near max_low_pfn or one pmd is not present.
435	 */
436	for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
437		va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
438		pgd = base + pgd_index(va);
439		if (!pgd_present(*pgd))
440			break;
441
442		p4d = p4d_offset(pgd, va);
443		pud = pud_offset(p4d, va);
444		pmd = pmd_offset(pud, va);
445		if (!pmd_present(*pmd))
446			break;
447
448		/* should not be large page here */
449		if (pmd_leaf(*pmd)) {
450			pr_warn("try to clear pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx, but pmd is big page and is not using pte !\n",
451				pfn, pmd, __pa(pmd));
452			BUG_ON(1);
453		}
454
455		pte = pte_offset_kernel(pmd, va);
456		if (!pte_present(*pte))
457			break;
458
459		printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n",
460				pfn, pmd, __pa(pmd), pte, __pa(pte));
461		pte_clear(NULL, va, pte);
462	}
463	paging_init();
464}
465
466/*
467 * Build a proper pagetable for the kernel mappings.  Up until this
468 * point, we've been running on some set of pagetables constructed by
469 * the boot process.
470 *
471 * This will be a pagetable constructed in arch/x86/kernel/head_32.S.
472 * The root of the pagetable will be swapper_pg_dir.
473 *
474 * In general, pagetable_init() assumes that the pagetable may already
475 * be partially populated, and so it avoids stomping on any existing
476 * mappings.
477 */
478void __init early_ioremap_page_table_range_init(void)
479{
480	pgd_t *pgd_base = swapper_pg_dir;
481	unsigned long vaddr, end;
482
483	/*
484	 * Fixed mappings, only the page table structure has to be
485	 * created - mappings will be set by set_fixmap():
486	 */
487	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
488	end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
489	page_table_range_init(vaddr, end, pgd_base);
490	early_ioremap_reset();
491}
492
493static void __init pagetable_init(void)
494{
495	pgd_t *pgd_base = swapper_pg_dir;
496
497	permanent_kmaps_init(pgd_base);
498}
499
500#define DEFAULT_PTE_MASK ~(_PAGE_NX | _PAGE_GLOBAL)
501/* Bits supported by the hardware: */
502pteval_t __supported_pte_mask __read_mostly = DEFAULT_PTE_MASK;
503/* Bits allowed in normal kernel mappings: */
504pteval_t __default_kernel_pte_mask __read_mostly = DEFAULT_PTE_MASK;
505EXPORT_SYMBOL_GPL(__supported_pte_mask);
506/* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */
507EXPORT_SYMBOL(__default_kernel_pte_mask);
508
509/* user-defined highmem size */
510static unsigned int highmem_pages = -1;
511
512/*
513 * highmem=size forces highmem to be exactly 'size' bytes.
514 * This works even on boxes that have no highmem otherwise.
515 * This also works to reduce highmem size on bigger boxes.
516 */
517static int __init parse_highmem(char *arg)
518{
519	if (!arg)
520		return -EINVAL;
521
522	highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
523	return 0;
524}
525early_param("highmem", parse_highmem);
526
527#define MSG_HIGHMEM_TOO_BIG \
528	"highmem size (%luMB) is bigger than pages available (%luMB)!\n"
529
530#define MSG_LOWMEM_TOO_SMALL \
531	"highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
532/*
533 * All of RAM fits into lowmem - but if user wants highmem
534 * artificially via the highmem=x boot parameter then create
535 * it:
536 */
537static void __init lowmem_pfn_init(void)
538{
539	/* max_low_pfn is 0, we already have early_res support */
540	max_low_pfn = max_pfn;
541
542	if (highmem_pages == -1)
543		highmem_pages = 0;
544#ifdef CONFIG_HIGHMEM
545	if (highmem_pages >= max_pfn) {
546		printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
547			pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
548		highmem_pages = 0;
549	}
550	if (highmem_pages) {
551		if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
552			printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
553				pages_to_mb(highmem_pages));
554			highmem_pages = 0;
555		}
556		max_low_pfn -= highmem_pages;
557	}
558#else
559	if (highmem_pages)
560		printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
561#endif
562}
563
564#define MSG_HIGHMEM_TOO_SMALL \
565	"only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
566
567#define MSG_HIGHMEM_TRIMMED \
568	"Warning: only 4GB will be used. Support for CONFIG_HIGHMEM64G was removed!\n"
569/*
570 * We have more RAM than fits into lowmem - we try to put it into
571 * highmem, also taking the highmem=x boot parameter into account:
572 */
573static void __init highmem_pfn_init(void)
574{
575	max_low_pfn = MAXMEM_PFN;
576
577	if (highmem_pages == -1)
578		highmem_pages = max_pfn - MAXMEM_PFN;
579
580	if (highmem_pages + MAXMEM_PFN < max_pfn)
581		max_pfn = MAXMEM_PFN + highmem_pages;
582
583	if (highmem_pages + MAXMEM_PFN > max_pfn) {
584		printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
585			pages_to_mb(max_pfn - MAXMEM_PFN),
586			pages_to_mb(highmem_pages));
587		highmem_pages = 0;
588	}
589#ifndef CONFIG_HIGHMEM
590	/* Maximum memory usable is what is directly addressable */
591	printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
592	printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
593	max_pfn = MAXMEM_PFN;
594#else /* !CONFIG_HIGHMEM */
595	if (max_pfn > MAX_NONPAE_PFN) {
596		max_pfn = MAX_NONPAE_PFN;
597		printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
598	}
599#endif /* !CONFIG_HIGHMEM */
600}
601
602/*
603 * Determine low and high memory ranges:
604 */
605void __init find_low_pfn_range(void)
606{
607	/* it could update max_pfn */
608
609	if (max_pfn <= MAXMEM_PFN)
610		lowmem_pfn_init();
611	else
612		highmem_pfn_init();
613}
614
615void __init initmem_init(void)
616{
617#ifdef CONFIG_HIGHMEM
618	highstart_pfn = highend_pfn = max_pfn;
619	if (max_pfn > max_low_pfn)
620		highstart_pfn = max_low_pfn;
621	printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
622		pages_to_mb(highend_pfn - highstart_pfn));
623	high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
624#else
625	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
626#endif
627
628	memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0);
629
630	__vmalloc_start_set = true;
631
632	printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
633			pages_to_mb(max_low_pfn));
634
635	printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
636		 max_pfn_mapped<<PAGE_SHIFT);
637	printk(KERN_INFO "  low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
638}
639
640/*
641 * paging_init() sets up the page tables - note that the first 8MB are
642 * already mapped by head.S.
643 *
644 * This routines also unmaps the page at virtual kernel address 0, so
645 * that we can trap those pesky NULL-reference errors in the kernel.
646 */
647void __init paging_init(void)
648{
649	pagetable_init();
650
651	__flush_tlb_all();
652
653	/*
654	 * NOTE: at this point the bootmem allocator is fully available.
655	 */
656	olpc_dt_build_devicetree();
657	sparse_init();
658	zone_sizes_init();
659}
660
661/*
662 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
663 * and also on some strange 486's. All 586+'s are OK. This used to involve
664 * black magic jumps to work around some nasty CPU bugs, but fortunately the
665 * switch to using exceptions got rid of all that.
666 */
667static void __init test_wp_bit(void)
668{
669	char z = 0;
670
671	printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode...");
672
673	__set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO);
674
675	if (copy_to_kernel_nofault((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) {
676		clear_fixmap(FIX_WP_TEST);
677		printk(KERN_CONT "Ok.\n");
678		return;
679	}
680
681	printk(KERN_CONT "No.\n");
682	panic("Linux doesn't support CPUs with broken WP.");
683}
684
685void __init arch_mm_preinit(void)
686{
687	pci_iommu_alloc();
688
689#ifdef CONFIG_FLATMEM
690	BUG_ON(!mem_map);
691#endif
692}
693
694void __init mem_init(void)
695{
696	after_bootmem = 1;
697	x86_init.hyper.init_after_bootmem();
698
699	/*
700	 * Check boundaries twice: Some fundamental inconsistencies can
701	 * be detected at build time already.
702	 */
703#define __FIXADDR_TOP (-PAGE_SIZE)
704#ifdef CONFIG_HIGHMEM
705	BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE	> FIXADDR_START);
706	BUILD_BUG_ON(VMALLOC_END			> PKMAP_BASE);
707#endif
708#define high_memory (-128UL << 20)
709	BUILD_BUG_ON(VMALLOC_START			>= VMALLOC_END);
710#undef high_memory
711#undef __FIXADDR_TOP
712
713#ifdef CONFIG_HIGHMEM
714	BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE	> FIXADDR_START);
715	BUG_ON(VMALLOC_END				> PKMAP_BASE);
716#endif
717	BUG_ON(VMALLOC_START				>= VMALLOC_END);
718	BUG_ON((unsigned long)high_memory		> VMALLOC_START);
719
720	test_wp_bit();
721}
722
723int kernel_set_to_readonly __read_mostly;
724
725static void mark_nxdata_nx(void)
726{
727	/*
728	 * When this called, init has already been executed and released,
729	 * so everything past _etext should be NX.
730	 */
731	unsigned long start = PFN_ALIGN(_etext);
732	/*
733	 * This comes from is_x86_32_kernel_text upper limit. Also HPAGE where used:
734	 */
735	unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start;
736
737	if (__supported_pte_mask & _PAGE_NX)
738		printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10);
739	set_memory_nx(start, size >> PAGE_SHIFT);
740}
741
742void mark_rodata_ro(void)
743{
744	unsigned long start = PFN_ALIGN(_text);
745	unsigned long size = (unsigned long)__end_rodata - start;
746
747	set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
748	pr_info("Write protecting kernel text and read-only data: %luk\n",
749		size >> 10);
750
751	kernel_set_to_readonly = 1;
752
753#ifdef CONFIG_CPA_DEBUG
754	pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size);
755	set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
756
757	pr_info("Testing CPA: write protecting again\n");
758	set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
759#endif
760	mark_nxdata_nx();
761}