xref: /openbmc/linux/arch/x86/mm/init_32.c (revision 545e4006)
1 /*
2  *
3  *  Copyright (C) 1995  Linus Torvalds
4  *
5  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
6  */
7 
8 #include <linux/module.h>
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/pfn.h>
25 #include <linux/poison.h>
26 #include <linux/bootmem.h>
27 #include <linux/slab.h>
28 #include <linux/proc_fs.h>
29 #include <linux/memory_hotplug.h>
30 #include <linux/initrd.h>
31 #include <linux/cpumask.h>
32 
33 #include <asm/asm.h>
34 #include <asm/processor.h>
35 #include <asm/system.h>
36 #include <asm/uaccess.h>
37 #include <asm/pgtable.h>
38 #include <asm/dma.h>
39 #include <asm/fixmap.h>
40 #include <asm/e820.h>
41 #include <asm/apic.h>
42 #include <asm/bugs.h>
43 #include <asm/tlb.h>
44 #include <asm/tlbflush.h>
45 #include <asm/pgalloc.h>
46 #include <asm/sections.h>
47 #include <asm/paravirt.h>
48 #include <asm/setup.h>
49 #include <asm/cacheflush.h>
50 
51 unsigned int __VMALLOC_RESERVE = 128 << 20;
52 
53 unsigned long max_low_pfn_mapped;
54 unsigned long max_pfn_mapped;
55 
56 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
57 unsigned long highstart_pfn, highend_pfn;
58 
59 static noinline int do_test_wp_bit(void);
60 
61 
62 static unsigned long __initdata table_start;
63 static unsigned long __meminitdata table_end;
64 static unsigned long __meminitdata table_top;
65 
66 static int __initdata after_init_bootmem;
67 
68 static __init void *alloc_low_page(unsigned long *phys)
69 {
70 	unsigned long pfn = table_end++;
71 	void *adr;
72 
73 	if (pfn >= table_top)
74 		panic("alloc_low_page: ran out of memory");
75 
76 	adr = __va(pfn * PAGE_SIZE);
77 	memset(adr, 0, PAGE_SIZE);
78 	*phys  = pfn * PAGE_SIZE;
79 	return adr;
80 }
81 
82 /*
83  * Creates a middle page table and puts a pointer to it in the
84  * given global directory entry. This only returns the gd entry
85  * in non-PAE compilation mode, since the middle layer is folded.
86  */
87 static pmd_t * __init one_md_table_init(pgd_t *pgd)
88 {
89 	pud_t *pud;
90 	pmd_t *pmd_table;
91 
92 #ifdef CONFIG_X86_PAE
93 	unsigned long phys;
94 	if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
95 		if (after_init_bootmem)
96 			pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
97 		else
98 			pmd_table = (pmd_t *)alloc_low_page(&phys);
99 		paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
100 		set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
101 		pud = pud_offset(pgd, 0);
102 		BUG_ON(pmd_table != pmd_offset(pud, 0));
103 	}
104 #endif
105 	pud = pud_offset(pgd, 0);
106 	pmd_table = pmd_offset(pud, 0);
107 
108 	return pmd_table;
109 }
110 
111 /*
112  * Create a page table and place a pointer to it in a middle page
113  * directory entry:
114  */
115 static pte_t * __init one_page_table_init(pmd_t *pmd)
116 {
117 	if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
118 		pte_t *page_table = NULL;
119 
120 		if (after_init_bootmem) {
121 #ifdef CONFIG_DEBUG_PAGEALLOC
122 			page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
123 #endif
124 			if (!page_table)
125 				page_table =
126 				(pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
127 		} else {
128 			unsigned long phys;
129 			page_table = (pte_t *)alloc_low_page(&phys);
130 		}
131 
132 		paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
133 		set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
134 		BUG_ON(page_table != pte_offset_kernel(pmd, 0));
135 	}
136 
137 	return pte_offset_kernel(pmd, 0);
138 }
139 
140 /*
141  * This function initializes a certain range of kernel virtual memory
142  * with new bootmem page tables, everywhere page tables are missing in
143  * the given range.
144  *
145  * NOTE: The pagetables are allocated contiguous on the physical space
146  * so we can cache the place of the first one and move around without
147  * checking the pgd every time.
148  */
149 static void __init
150 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
151 {
152 	int pgd_idx, pmd_idx;
153 	unsigned long vaddr;
154 	pgd_t *pgd;
155 	pmd_t *pmd;
156 
157 	vaddr = start;
158 	pgd_idx = pgd_index(vaddr);
159 	pmd_idx = pmd_index(vaddr);
160 	pgd = pgd_base + pgd_idx;
161 
162 	for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
163 		pmd = one_md_table_init(pgd);
164 		pmd = pmd + pmd_index(vaddr);
165 		for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
166 							pmd++, pmd_idx++) {
167 			one_page_table_init(pmd);
168 
169 			vaddr += PMD_SIZE;
170 		}
171 		pmd_idx = 0;
172 	}
173 }
174 
175 static inline int is_kernel_text(unsigned long addr)
176 {
177 	if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
178 		return 1;
179 	return 0;
180 }
181 
182 /*
183  * This maps the physical memory to kernel virtual address space, a total
184  * of max_low_pfn pages, by creating page tables starting from address
185  * PAGE_OFFSET:
186  */
187 static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
188 						unsigned long start_pfn,
189 						unsigned long end_pfn,
190 						int use_pse)
191 {
192 	int pgd_idx, pmd_idx, pte_ofs;
193 	unsigned long pfn;
194 	pgd_t *pgd;
195 	pmd_t *pmd;
196 	pte_t *pte;
197 	unsigned pages_2m = 0, pages_4k = 0;
198 
199 	if (!cpu_has_pse)
200 		use_pse = 0;
201 
202 	pfn = start_pfn;
203 	pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
204 	pgd = pgd_base + pgd_idx;
205 	for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
206 		pmd = one_md_table_init(pgd);
207 
208 		if (pfn >= end_pfn)
209 			continue;
210 #ifdef CONFIG_X86_PAE
211 		pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
212 		pmd += pmd_idx;
213 #else
214 		pmd_idx = 0;
215 #endif
216 		for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
217 		     pmd++, pmd_idx++) {
218 			unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
219 
220 			/*
221 			 * Map with big pages if possible, otherwise
222 			 * create normal page tables:
223 			 */
224 			if (use_pse) {
225 				unsigned int addr2;
226 				pgprot_t prot = PAGE_KERNEL_LARGE;
227 
228 				addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
229 					PAGE_OFFSET + PAGE_SIZE-1;
230 
231 				if (is_kernel_text(addr) ||
232 				    is_kernel_text(addr2))
233 					prot = PAGE_KERNEL_LARGE_EXEC;
234 
235 				pages_2m++;
236 				set_pmd(pmd, pfn_pmd(pfn, prot));
237 
238 				pfn += PTRS_PER_PTE;
239 				continue;
240 			}
241 			pte = one_page_table_init(pmd);
242 
243 			pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
244 			pte += pte_ofs;
245 			for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
246 			     pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
247 				pgprot_t prot = PAGE_KERNEL;
248 
249 				if (is_kernel_text(addr))
250 					prot = PAGE_KERNEL_EXEC;
251 
252 				pages_4k++;
253 				set_pte(pte, pfn_pte(pfn, prot));
254 			}
255 		}
256 	}
257 	update_page_count(PG_LEVEL_2M, pages_2m);
258 	update_page_count(PG_LEVEL_4K, pages_4k);
259 }
260 
261 /*
262  * devmem_is_allowed() checks to see if /dev/mem access to a certain address
263  * is valid. The argument is a physical page number.
264  *
265  *
266  * On x86, access has to be given to the first megabyte of ram because that area
267  * contains bios code and data regions used by X and dosemu and similar apps.
268  * Access has to be given to non-kernel-ram areas as well, these contain the PCI
269  * mmio resources as well as potential bios/acpi data regions.
270  */
271 int devmem_is_allowed(unsigned long pagenr)
272 {
273 	if (pagenr <= 256)
274 		return 1;
275 	if (!page_is_ram(pagenr))
276 		return 1;
277 	return 0;
278 }
279 
280 #ifdef CONFIG_HIGHMEM
281 pte_t *kmap_pte;
282 pgprot_t kmap_prot;
283 
284 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
285 {
286 	return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
287 			vaddr), vaddr), vaddr);
288 }
289 
290 static void __init kmap_init(void)
291 {
292 	unsigned long kmap_vstart;
293 
294 	/*
295 	 * Cache the first kmap pte:
296 	 */
297 	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
298 	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
299 
300 	kmap_prot = PAGE_KERNEL;
301 }
302 
303 static void __init permanent_kmaps_init(pgd_t *pgd_base)
304 {
305 	unsigned long vaddr;
306 	pgd_t *pgd;
307 	pud_t *pud;
308 	pmd_t *pmd;
309 	pte_t *pte;
310 
311 	vaddr = PKMAP_BASE;
312 	page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
313 
314 	pgd = swapper_pg_dir + pgd_index(vaddr);
315 	pud = pud_offset(pgd, vaddr);
316 	pmd = pmd_offset(pud, vaddr);
317 	pte = pte_offset_kernel(pmd, vaddr);
318 	pkmap_page_table = pte;
319 }
320 
321 static void __init add_one_highpage_init(struct page *page, int pfn)
322 {
323 	ClearPageReserved(page);
324 	init_page_count(page);
325 	__free_page(page);
326 	totalhigh_pages++;
327 }
328 
329 struct add_highpages_data {
330 	unsigned long start_pfn;
331 	unsigned long end_pfn;
332 };
333 
334 static int __init add_highpages_work_fn(unsigned long start_pfn,
335 					 unsigned long end_pfn, void *datax)
336 {
337 	int node_pfn;
338 	struct page *page;
339 	unsigned long final_start_pfn, final_end_pfn;
340 	struct add_highpages_data *data;
341 
342 	data = (struct add_highpages_data *)datax;
343 
344 	final_start_pfn = max(start_pfn, data->start_pfn);
345 	final_end_pfn = min(end_pfn, data->end_pfn);
346 	if (final_start_pfn >= final_end_pfn)
347 		return 0;
348 
349 	for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
350 	     node_pfn++) {
351 		if (!pfn_valid(node_pfn))
352 			continue;
353 		page = pfn_to_page(node_pfn);
354 		add_one_highpage_init(page, node_pfn);
355 	}
356 
357 	return 0;
358 
359 }
360 
361 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
362 					      unsigned long end_pfn)
363 {
364 	struct add_highpages_data data;
365 
366 	data.start_pfn = start_pfn;
367 	data.end_pfn = end_pfn;
368 
369 	work_with_active_regions(nid, add_highpages_work_fn, &data);
370 }
371 
372 #ifndef CONFIG_NUMA
373 static void __init set_highmem_pages_init(void)
374 {
375 	add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
376 
377 	totalram_pages += totalhigh_pages;
378 }
379 #endif /* !CONFIG_NUMA */
380 
381 #else
382 # define kmap_init()				do { } while (0)
383 # define permanent_kmaps_init(pgd_base)		do { } while (0)
384 # define set_highmem_pages_init()	do { } while (0)
385 #endif /* CONFIG_HIGHMEM */
386 
387 void __init native_pagetable_setup_start(pgd_t *base)
388 {
389 	unsigned long pfn, va;
390 	pgd_t *pgd;
391 	pud_t *pud;
392 	pmd_t *pmd;
393 	pte_t *pte;
394 
395 	/*
396 	 * Remove any mappings which extend past the end of physical
397 	 * memory from the boot time page table:
398 	 */
399 	for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
400 		va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
401 		pgd = base + pgd_index(va);
402 		if (!pgd_present(*pgd))
403 			break;
404 
405 		pud = pud_offset(pgd, va);
406 		pmd = pmd_offset(pud, va);
407 		if (!pmd_present(*pmd))
408 			break;
409 
410 		pte = pte_offset_kernel(pmd, va);
411 		if (!pte_present(*pte))
412 			break;
413 
414 		pte_clear(NULL, va, pte);
415 	}
416 	paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
417 }
418 
419 void __init native_pagetable_setup_done(pgd_t *base)
420 {
421 }
422 
423 /*
424  * Build a proper pagetable for the kernel mappings.  Up until this
425  * point, we've been running on some set of pagetables constructed by
426  * the boot process.
427  *
428  * If we're booting on native hardware, this will be a pagetable
429  * constructed in arch/x86/kernel/head_32.S.  The root of the
430  * pagetable will be swapper_pg_dir.
431  *
432  * If we're booting paravirtualized under a hypervisor, then there are
433  * more options: we may already be running PAE, and the pagetable may
434  * or may not be based in swapper_pg_dir.  In any case,
435  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
436  * appropriately for the rest of the initialization to work.
437  *
438  * In general, pagetable_init() assumes that the pagetable may already
439  * be partially populated, and so it avoids stomping on any existing
440  * mappings.
441  */
442 static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
443 {
444 	unsigned long vaddr, end;
445 
446 	/*
447 	 * Fixed mappings, only the page table structure has to be
448 	 * created - mappings will be set by set_fixmap():
449 	 */
450 	early_ioremap_clear();
451 	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
452 	end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
453 	page_table_range_init(vaddr, end, pgd_base);
454 	early_ioremap_reset();
455 }
456 
457 static void __init pagetable_init(void)
458 {
459 	pgd_t *pgd_base = swapper_pg_dir;
460 
461 	paravirt_pagetable_setup_start(pgd_base);
462 
463 	permanent_kmaps_init(pgd_base);
464 
465 	paravirt_pagetable_setup_done(pgd_base);
466 }
467 
468 #ifdef CONFIG_ACPI_SLEEP
469 /*
470  * ACPI suspend needs this for resume, because things like the intel-agp
471  * driver might have split up a kernel 4MB mapping.
472  */
473 char swsusp_pg_dir[PAGE_SIZE]
474 	__attribute__ ((aligned(PAGE_SIZE)));
475 
476 static inline void save_pg_dir(void)
477 {
478 	memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
479 }
480 #else /* !CONFIG_ACPI_SLEEP */
481 static inline void save_pg_dir(void)
482 {
483 }
484 #endif /* !CONFIG_ACPI_SLEEP */
485 
486 void zap_low_mappings(void)
487 {
488 	int i;
489 
490 	/*
491 	 * Zap initial low-memory mappings.
492 	 *
493 	 * Note that "pgd_clear()" doesn't do it for
494 	 * us, because pgd_clear() is a no-op on i386.
495 	 */
496 	for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
497 #ifdef CONFIG_X86_PAE
498 		set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
499 #else
500 		set_pgd(swapper_pg_dir+i, __pgd(0));
501 #endif
502 	}
503 	flush_tlb_all();
504 }
505 
506 int nx_enabled;
507 
508 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL);
509 EXPORT_SYMBOL_GPL(__supported_pte_mask);
510 
511 #ifdef CONFIG_X86_PAE
512 
513 static int disable_nx __initdata;
514 
515 /*
516  * noexec = on|off
517  *
518  * Control non executable mappings.
519  *
520  * on      Enable
521  * off     Disable
522  */
523 static int __init noexec_setup(char *str)
524 {
525 	if (!str || !strcmp(str, "on")) {
526 		if (cpu_has_nx) {
527 			__supported_pte_mask |= _PAGE_NX;
528 			disable_nx = 0;
529 		}
530 	} else {
531 		if (!strcmp(str, "off")) {
532 			disable_nx = 1;
533 			__supported_pte_mask &= ~_PAGE_NX;
534 		} else {
535 			return -EINVAL;
536 		}
537 	}
538 
539 	return 0;
540 }
541 early_param("noexec", noexec_setup);
542 
543 static void __init set_nx(void)
544 {
545 	unsigned int v[4], l, h;
546 
547 	if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
548 		cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
549 
550 		if ((v[3] & (1 << 20)) && !disable_nx) {
551 			rdmsr(MSR_EFER, l, h);
552 			l |= EFER_NX;
553 			wrmsr(MSR_EFER, l, h);
554 			nx_enabled = 1;
555 			__supported_pte_mask |= _PAGE_NX;
556 		}
557 	}
558 }
559 #endif
560 
561 /* user-defined highmem size */
562 static unsigned int highmem_pages = -1;
563 
564 /*
565  * highmem=size forces highmem to be exactly 'size' bytes.
566  * This works even on boxes that have no highmem otherwise.
567  * This also works to reduce highmem size on bigger boxes.
568  */
569 static int __init parse_highmem(char *arg)
570 {
571 	if (!arg)
572 		return -EINVAL;
573 
574 	highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
575 	return 0;
576 }
577 early_param("highmem", parse_highmem);
578 
579 /*
580  * Determine low and high memory ranges:
581  */
582 void __init find_low_pfn_range(void)
583 {
584 	/* it could update max_pfn */
585 
586 	/* max_low_pfn is 0, we already have early_res support */
587 
588 	max_low_pfn = max_pfn;
589 	if (max_low_pfn > MAXMEM_PFN) {
590 		if (highmem_pages == -1)
591 			highmem_pages = max_pfn - MAXMEM_PFN;
592 		if (highmem_pages + MAXMEM_PFN < max_pfn)
593 			max_pfn = MAXMEM_PFN + highmem_pages;
594 		if (highmem_pages + MAXMEM_PFN > max_pfn) {
595 			printk(KERN_WARNING "only %luMB highmem pages "
596 				"available, ignoring highmem size of %uMB.\n",
597 				pages_to_mb(max_pfn - MAXMEM_PFN),
598 				pages_to_mb(highmem_pages));
599 			highmem_pages = 0;
600 		}
601 		max_low_pfn = MAXMEM_PFN;
602 #ifndef CONFIG_HIGHMEM
603 		/* Maximum memory usable is what is directly addressable */
604 		printk(KERN_WARNING "Warning only %ldMB will be used.\n",
605 					MAXMEM>>20);
606 		if (max_pfn > MAX_NONPAE_PFN)
607 			printk(KERN_WARNING
608 				 "Use a HIGHMEM64G enabled kernel.\n");
609 		else
610 			printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
611 		max_pfn = MAXMEM_PFN;
612 #else /* !CONFIG_HIGHMEM */
613 #ifndef CONFIG_HIGHMEM64G
614 		if (max_pfn > MAX_NONPAE_PFN) {
615 			max_pfn = MAX_NONPAE_PFN;
616 			printk(KERN_WARNING "Warning only 4GB will be used."
617 				"Use a HIGHMEM64G enabled kernel.\n");
618 		}
619 #endif /* !CONFIG_HIGHMEM64G */
620 #endif /* !CONFIG_HIGHMEM */
621 	} else {
622 		if (highmem_pages == -1)
623 			highmem_pages = 0;
624 #ifdef CONFIG_HIGHMEM
625 		if (highmem_pages >= max_pfn) {
626 			printk(KERN_ERR "highmem size specified (%uMB) is "
627 				"bigger than pages available (%luMB)!.\n",
628 				pages_to_mb(highmem_pages),
629 				pages_to_mb(max_pfn));
630 			highmem_pages = 0;
631 		}
632 		if (highmem_pages) {
633 			if (max_low_pfn - highmem_pages <
634 			    64*1024*1024/PAGE_SIZE){
635 				printk(KERN_ERR "highmem size %uMB results in "
636 				"smaller than 64MB lowmem, ignoring it.\n"
637 					, pages_to_mb(highmem_pages));
638 				highmem_pages = 0;
639 			}
640 			max_low_pfn -= highmem_pages;
641 		}
642 #else
643 		if (highmem_pages)
644 			printk(KERN_ERR "ignoring highmem size on non-highmem"
645 					" kernel!\n");
646 #endif
647 	}
648 }
649 
650 #ifndef CONFIG_NEED_MULTIPLE_NODES
651 void __init initmem_init(unsigned long start_pfn,
652 				  unsigned long end_pfn)
653 {
654 #ifdef CONFIG_HIGHMEM
655 	highstart_pfn = highend_pfn = max_pfn;
656 	if (max_pfn > max_low_pfn)
657 		highstart_pfn = max_low_pfn;
658 	memory_present(0, 0, highend_pfn);
659 	e820_register_active_regions(0, 0, highend_pfn);
660 	printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
661 		pages_to_mb(highend_pfn - highstart_pfn));
662 	num_physpages = highend_pfn;
663 	high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
664 #else
665 	memory_present(0, 0, max_low_pfn);
666 	e820_register_active_regions(0, 0, max_low_pfn);
667 	num_physpages = max_low_pfn;
668 	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
669 #endif
670 #ifdef CONFIG_FLATMEM
671 	max_mapnr = num_physpages;
672 #endif
673 	printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
674 			pages_to_mb(max_low_pfn));
675 
676 	setup_bootmem_allocator();
677 }
678 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
679 
680 static void __init zone_sizes_init(void)
681 {
682 	unsigned long max_zone_pfns[MAX_NR_ZONES];
683 	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
684 	max_zone_pfns[ZONE_DMA] =
685 		virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
686 	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
687 #ifdef CONFIG_HIGHMEM
688 	max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
689 #endif
690 
691 	free_area_init_nodes(max_zone_pfns);
692 }
693 
694 void __init setup_bootmem_allocator(void)
695 {
696 	int i;
697 	unsigned long bootmap_size, bootmap;
698 	/*
699 	 * Initialize the boot-time allocator (with low memory only):
700 	 */
701 	bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
702 	bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
703 				 max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
704 				 PAGE_SIZE);
705 	if (bootmap == -1L)
706 		panic("Cannot find bootmem map of size %ld\n", bootmap_size);
707 	reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
708 
709 	/* don't touch min_low_pfn */
710 	bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
711 					 min_low_pfn, max_low_pfn);
712 	printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
713 		 max_pfn_mapped<<PAGE_SHIFT);
714 	printk(KERN_INFO "  low ram: %08lx - %08lx\n",
715 		 min_low_pfn<<PAGE_SHIFT, max_low_pfn<<PAGE_SHIFT);
716 	printk(KERN_INFO "  bootmap %08lx - %08lx\n",
717 		 bootmap, bootmap + bootmap_size);
718 	for_each_online_node(i)
719 		free_bootmem_with_active_regions(i, max_low_pfn);
720 	early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
721 
722 	after_init_bootmem = 1;
723 }
724 
725 static void __init find_early_table_space(unsigned long end)
726 {
727 	unsigned long puds, pmds, ptes, tables, start;
728 
729 	puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
730 	tables = PAGE_ALIGN(puds * sizeof(pud_t));
731 
732 	pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
733 	tables += PAGE_ALIGN(pmds * sizeof(pmd_t));
734 
735 	if (cpu_has_pse) {
736 		unsigned long extra;
737 
738 		extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
739 		extra += PMD_SIZE;
740 		ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
741 	} else
742 		ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
743 
744 	tables += PAGE_ALIGN(ptes * sizeof(pte_t));
745 
746 	/* for fixmap */
747 	tables += PAGE_SIZE * 2;
748 
749 	/*
750 	 * RED-PEN putting page tables only on node 0 could
751 	 * cause a hotspot and fill up ZONE_DMA. The page tables
752 	 * need roughly 0.5KB per GB.
753 	 */
754 	start = 0x7000;
755 	table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
756 					tables, PAGE_SIZE);
757 	if (table_start == -1UL)
758 		panic("Cannot find space for the kernel page tables");
759 
760 	table_start >>= PAGE_SHIFT;
761 	table_end = table_start;
762 	table_top = table_start + (tables>>PAGE_SHIFT);
763 
764 	printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
765 		end, table_start << PAGE_SHIFT,
766 		(table_start << PAGE_SHIFT) + tables);
767 }
768 
769 unsigned long __init_refok init_memory_mapping(unsigned long start,
770 						unsigned long end)
771 {
772 	pgd_t *pgd_base = swapper_pg_dir;
773 	unsigned long start_pfn, end_pfn;
774 	unsigned long big_page_start;
775 
776 	/*
777 	 * Find space for the kernel direct mapping tables.
778 	 */
779 	if (!after_init_bootmem)
780 		find_early_table_space(end);
781 
782 #ifdef CONFIG_X86_PAE
783 	set_nx();
784 	if (nx_enabled)
785 		printk(KERN_INFO "NX (Execute Disable) protection: active\n");
786 #endif
787 
788 	/* Enable PSE if available */
789 	if (cpu_has_pse)
790 		set_in_cr4(X86_CR4_PSE);
791 
792 	/* Enable PGE if available */
793 	if (cpu_has_pge) {
794 		set_in_cr4(X86_CR4_PGE);
795 		__supported_pte_mask |= _PAGE_GLOBAL;
796 	}
797 
798 	/*
799 	 * Don't use a large page for the first 2/4MB of memory
800 	 * because there are often fixed size MTRRs in there
801 	 * and overlapping MTRRs into large pages can cause
802 	 * slowdowns.
803 	 */
804 	big_page_start = PMD_SIZE;
805 
806 	if (start < big_page_start) {
807 		start_pfn = start >> PAGE_SHIFT;
808 		end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
809 	} else {
810 		/* head is not big page alignment ? */
811 		start_pfn = start >> PAGE_SHIFT;
812 		end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
813 				 << (PMD_SHIFT - PAGE_SHIFT);
814 	}
815 	if (start_pfn < end_pfn)
816 		kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
817 
818 	/* big page range */
819 	start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
820 			 << (PMD_SHIFT - PAGE_SHIFT);
821 	if (start_pfn < (big_page_start >> PAGE_SHIFT))
822 		start_pfn =  big_page_start >> PAGE_SHIFT;
823 	end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
824 	if (start_pfn < end_pfn)
825 		kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
826 						cpu_has_pse);
827 
828 	/* tail is not big page alignment ? */
829 	start_pfn = end_pfn;
830 	if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
831 		end_pfn = end >> PAGE_SHIFT;
832 		if (start_pfn < end_pfn)
833 			kernel_physical_mapping_init(pgd_base, start_pfn,
834 							 end_pfn, 0);
835 	}
836 
837 	early_ioremap_page_table_range_init(pgd_base);
838 
839 	load_cr3(swapper_pg_dir);
840 
841 	__flush_tlb_all();
842 
843 	if (!after_init_bootmem)
844 		reserve_early(table_start << PAGE_SHIFT,
845 				 table_end << PAGE_SHIFT, "PGTABLE");
846 
847 	if (!after_init_bootmem)
848 		early_memtest(start, end);
849 
850 	return end >> PAGE_SHIFT;
851 }
852 
853 
854 /*
855  * paging_init() sets up the page tables - note that the first 8MB are
856  * already mapped by head.S.
857  *
858  * This routines also unmaps the page at virtual kernel address 0, so
859  * that we can trap those pesky NULL-reference errors in the kernel.
860  */
861 void __init paging_init(void)
862 {
863 	pagetable_init();
864 
865 	__flush_tlb_all();
866 
867 	kmap_init();
868 
869 	/*
870 	 * NOTE: at this point the bootmem allocator is fully available.
871 	 */
872 	sparse_init();
873 	zone_sizes_init();
874 }
875 
876 /*
877  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
878  * and also on some strange 486's. All 586+'s are OK. This used to involve
879  * black magic jumps to work around some nasty CPU bugs, but fortunately the
880  * switch to using exceptions got rid of all that.
881  */
882 static void __init test_wp_bit(void)
883 {
884 	printk(KERN_INFO
885   "Checking if this processor honours the WP bit even in supervisor mode...");
886 
887 	/* Any page-aligned address will do, the test is non-destructive */
888 	__set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
889 	boot_cpu_data.wp_works_ok = do_test_wp_bit();
890 	clear_fixmap(FIX_WP_TEST);
891 
892 	if (!boot_cpu_data.wp_works_ok) {
893 		printk(KERN_CONT "No.\n");
894 #ifdef CONFIG_X86_WP_WORKS_OK
895 		panic(
896   "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
897 #endif
898 	} else {
899 		printk(KERN_CONT "Ok.\n");
900 	}
901 }
902 
903 static struct kcore_list kcore_mem, kcore_vmalloc;
904 
905 void __init mem_init(void)
906 {
907 	int codesize, reservedpages, datasize, initsize;
908 	int tmp;
909 
910 #ifdef CONFIG_FLATMEM
911 	BUG_ON(!mem_map);
912 #endif
913 	/* this will put all low memory onto the freelists */
914 	totalram_pages += free_all_bootmem();
915 
916 	reservedpages = 0;
917 	for (tmp = 0; tmp < max_low_pfn; tmp++)
918 		/*
919 		 * Only count reserved RAM pages:
920 		 */
921 		if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
922 			reservedpages++;
923 
924 	set_highmem_pages_init();
925 
926 	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
927 	datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
928 	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
929 
930 	kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
931 	kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
932 		   VMALLOC_END-VMALLOC_START);
933 
934 	printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
935 			"%dk reserved, %dk data, %dk init, %ldk highmem)\n",
936 		(unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
937 		num_physpages << (PAGE_SHIFT-10),
938 		codesize >> 10,
939 		reservedpages << (PAGE_SHIFT-10),
940 		datasize >> 10,
941 		initsize >> 10,
942 		(unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
943 	       );
944 
945 	printk(KERN_INFO "virtual kernel memory layout:\n"
946 		"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
947 #ifdef CONFIG_HIGHMEM
948 		"    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
949 #endif
950 		"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
951 		"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
952 		"      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
953 		"      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
954 		"      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
955 		FIXADDR_START, FIXADDR_TOP,
956 		(FIXADDR_TOP - FIXADDR_START) >> 10,
957 
958 #ifdef CONFIG_HIGHMEM
959 		PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
960 		(LAST_PKMAP*PAGE_SIZE) >> 10,
961 #endif
962 
963 		VMALLOC_START, VMALLOC_END,
964 		(VMALLOC_END - VMALLOC_START) >> 20,
965 
966 		(unsigned long)__va(0), (unsigned long)high_memory,
967 		((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
968 
969 		(unsigned long)&__init_begin, (unsigned long)&__init_end,
970 		((unsigned long)&__init_end -
971 		 (unsigned long)&__init_begin) >> 10,
972 
973 		(unsigned long)&_etext, (unsigned long)&_edata,
974 		((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
975 
976 		(unsigned long)&_text, (unsigned long)&_etext,
977 		((unsigned long)&_etext - (unsigned long)&_text) >> 10);
978 
979 #ifdef CONFIG_HIGHMEM
980 	BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE	> FIXADDR_START);
981 	BUG_ON(VMALLOC_END				> PKMAP_BASE);
982 #endif
983 	BUG_ON(VMALLOC_START				> VMALLOC_END);
984 	BUG_ON((unsigned long)high_memory		> VMALLOC_START);
985 
986 	if (boot_cpu_data.wp_works_ok < 0)
987 		test_wp_bit();
988 
989 	cpa_init();
990 	save_pg_dir();
991 	zap_low_mappings();
992 }
993 
994 #ifdef CONFIG_MEMORY_HOTPLUG
995 int arch_add_memory(int nid, u64 start, u64 size)
996 {
997 	struct pglist_data *pgdata = NODE_DATA(nid);
998 	struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
999 	unsigned long start_pfn = start >> PAGE_SHIFT;
1000 	unsigned long nr_pages = size >> PAGE_SHIFT;
1001 
1002 	return __add_pages(zone, start_pfn, nr_pages);
1003 }
1004 #endif
1005 
1006 /*
1007  * This function cannot be __init, since exceptions don't work in that
1008  * section.  Put this after the callers, so that it cannot be inlined.
1009  */
1010 static noinline int do_test_wp_bit(void)
1011 {
1012 	char tmp_reg;
1013 	int flag;
1014 
1015 	__asm__ __volatile__(
1016 		"	movb %0, %1	\n"
1017 		"1:	movb %1, %0	\n"
1018 		"	xorl %2, %2	\n"
1019 		"2:			\n"
1020 		_ASM_EXTABLE(1b,2b)
1021 		:"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1022 		 "=q" (tmp_reg),
1023 		 "=r" (flag)
1024 		:"2" (1)
1025 		:"memory");
1026 
1027 	return flag;
1028 }
1029 
1030 #ifdef CONFIG_DEBUG_RODATA
1031 const int rodata_test_data = 0xC3;
1032 EXPORT_SYMBOL_GPL(rodata_test_data);
1033 
1034 void mark_rodata_ro(void)
1035 {
1036 	unsigned long start = PFN_ALIGN(_text);
1037 	unsigned long size = PFN_ALIGN(_etext) - start;
1038 
1039 #ifndef CONFIG_DYNAMIC_FTRACE
1040 	/* Dynamic tracing modifies the kernel text section */
1041 	set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1042 	printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1043 		size >> 10);
1044 
1045 #ifdef CONFIG_CPA_DEBUG
1046 	printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1047 		start, start+size);
1048 	set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1049 
1050 	printk(KERN_INFO "Testing CPA: write protecting again\n");
1051 	set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1052 #endif
1053 #endif /* CONFIG_DYNAMIC_FTRACE */
1054 
1055 	start += size;
1056 	size = (unsigned long)__end_rodata - start;
1057 	set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1058 	printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1059 		size >> 10);
1060 	rodata_test();
1061 
1062 #ifdef CONFIG_CPA_DEBUG
1063 	printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1064 	set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1065 
1066 	printk(KERN_INFO "Testing CPA: write protecting again\n");
1067 	set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1068 #endif
1069 }
1070 #endif
1071 
1072 void free_init_pages(char *what, unsigned long begin, unsigned long end)
1073 {
1074 #ifdef CONFIG_DEBUG_PAGEALLOC
1075 	/*
1076 	 * If debugging page accesses then do not free this memory but
1077 	 * mark them not present - any buggy init-section access will
1078 	 * create a kernel page fault:
1079 	 */
1080 	printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
1081 		begin, PAGE_ALIGN(end));
1082 	set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
1083 #else
1084 	unsigned long addr;
1085 
1086 	/*
1087 	 * We just marked the kernel text read only above, now that
1088 	 * we are going to free part of that, we need to make that
1089 	 * writeable first.
1090 	 */
1091 	set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
1092 
1093 	for (addr = begin; addr < end; addr += PAGE_SIZE) {
1094 		ClearPageReserved(virt_to_page(addr));
1095 		init_page_count(virt_to_page(addr));
1096 		memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
1097 		free_page(addr);
1098 		totalram_pages++;
1099 	}
1100 	printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
1101 #endif
1102 }
1103 
1104 void free_initmem(void)
1105 {
1106 	free_init_pages("unused kernel memory",
1107 			(unsigned long)(&__init_begin),
1108 			(unsigned long)(&__init_end));
1109 }
1110 
1111 #ifdef CONFIG_BLK_DEV_INITRD
1112 void free_initrd_mem(unsigned long start, unsigned long end)
1113 {
1114 	free_init_pages("initrd memory", start, end);
1115 }
1116 #endif
1117 
1118 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1119 				   int flags)
1120 {
1121 	return reserve_bootmem(phys, len, flags);
1122 }
1123