summaryrefslogtreecommitdiffstats
path: root/arch/i386/mm/init.c
blob: 06e26f0062382301e02c13a6c2fa24617a48b663 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
/*
 *  linux/arch/i386/mm/init.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *
 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/efi.h>
#include <linux/memory_hotplug.h>
#include <linux/initrd.h>

#include <asm/processor.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/dma.h>
#include <asm/fixmap.h>
#include <asm/e820.h>
#include <asm/apic.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>

unsigned int __VMALLOC_RESERVE = 128 << 20;

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
unsigned long highstart_pfn, highend_pfn;

static int noinline do_test_wp_bit(void);

/*
 * Creates a middle page table and puts a pointer to it in the
 * given global directory entry. This only returns the gd entry
 * in non-PAE compilation mode, since the middle layer is folded.
 */
static pmd_t * __init one_md_table_init(pgd_t *pgd)
{
	pud_t *pud;
	pmd_t *pmd_table;
		
#ifdef CONFIG_X86_PAE
	pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
	set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
	pud = pud_offset(pgd, 0);
	if (pmd_table != pmd_offset(pud, 0)) 
		BUG();
#else
	pud = pud_offset(pgd, 0);
	pmd_table = pmd_offset(pud, 0);
#endif

	return pmd_table;
}

/*
 * Create a page table and place a pointer to it in a middle page
 * directory entry.
 */
static pte_t * __init one_page_table_init(pmd_t *pmd)
{
	if (pmd_none(*pmd)) {
		pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
		set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
		if (page_table != pte_offset_kernel(pmd, 0))
			BUG();	

		return page_table;
	}
	
	return pte_offset_kernel(pmd, 0);
}

/*
 * This function initializes a certain range of kernel virtual memory 
 * with new bootmem page tables, everywhere page tables are missing in
 * the given range.
 */

/*
 * NOTE: The pagetables are allocated contiguous on the physical space 
 * so we can cache the place of the first one and move around without 
 * checking the pgd every time.
 */
static void __init page_table_range_init (unsigned long start, unsigned long end, pgd_t *pgd_base)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	int pgd_idx, pmd_idx;
	unsigned long vaddr;

	vaddr = start;
	pgd_idx = pgd_index(vaddr);
	pmd_idx = pmd_index(vaddr);
	pgd = pgd_base + pgd_idx;

	for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
		if (pgd_none(*pgd)) 
			one_md_table_init(pgd);
		pud = pud_offset(pgd, vaddr);
		pmd = pmd_offset(pud, vaddr);
		for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) {
			if (pmd_none(*pmd)) 
				one_page_table_init(pmd);

			vaddr += PMD_SIZE;
		}
		pmd_idx = 0;
	}
}

static inline int is_kernel_text(unsigned long addr)
{
	if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
		return 1;
	return 0;
}

/*
 * This maps the physical memory to kernel virtual address space, a total 
 * of max_low_pfn pages, by creating page tables starting from address 
 * PAGE_OFFSET.
 */
static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
{
	unsigned long pfn;
	pgd_t *pgd;
	pmd_t *pmd;
	pte_t *pte;
	int pgd_idx, pmd_idx, pte_ofs;

	pgd_idx = pgd_index(PAGE_OFFSET);
	pgd = pgd_base + pgd_idx;
	pfn = 0;

	for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
		pmd = one_md_table_init(pgd);
		if (pfn >= max_low_pfn)
			continue;
		for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_idx++) {
			unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET;

			/* Map with big pages if possible, otherwise create normal page tables. */
			if (cpu_has_pse) {
				unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;

				if (is_kernel_text(address) || is_kernel_text(address2))
					set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
				else
					set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
				pfn += PTRS_PER_PTE;
			} else {
				pte = one_page_table_init(pmd);

				for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++) {
						if (is_kernel_text(address))
							set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
						else
							set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
				}
			}
		}
	}
}

static inline int page_kills_ppro(unsigned long pagenr)
{
	if (pagenr >= 0x70000 && pagenr <= 0x7003F)
		return 1;
	return 0;
}

extern int is_available_memory(efi_memory_desc_t *);

int page_is_ram(unsigned long pagenr)
{
	int i;
	unsigned long addr, end;

	if (efi_enabled) {
		efi_memory_desc_t *md;
		void *p;

		for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
			md = p;
			if (!is_available_memory(md))
				continue;
			addr = (md->phys_addr+PAGE_SIZE-1) >> PAGE_SHIFT;
			end = (md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT)) >> PAGE_SHIFT;

			if ((pagenr >= addr) && (pagenr < end))
				return 1;
		}
		return 0;
	}

	for (i = 0; i < e820.nr_map; i++) {

		if (e820.map[i].type != E820_RAM)	/* not usable memory */
			continue;
		/*
		 *	!!!FIXME!!! Some BIOSen report areas as RAM that
		 *	are not. Notably the 640->1Mb area. We need a sanity
		 *	check here.
		 */
		addr = (e820.map[i].addr+PAGE_SIZE-1) >> PAGE_SHIFT;
		end = (e820.map[i].addr+e820.map[i].size) >> PAGE_SHIFT;
		if  ((pagenr >= addr) && (pagenr < end))
			return 1;
	}
	return 0;
}

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;

#define kmap_get_fixmap_pte(vaddr)					\
	pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), vaddr), (vaddr)), (vaddr))

static void __init kmap_init(void)
{
	unsigned long kmap_vstart;

	/* cache the first kmap pte */
	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);

	kmap_prot = PAGE_KERNEL;
}

static void __init permanent_kmaps_init(pgd_t *pgd_base)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	unsigned long vaddr;

	vaddr = PKMAP_BASE;
	page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);

	pgd = swapper_pg_dir + pgd_index(vaddr);
	pud = pud_offset(pgd, vaddr);
	pmd = pmd_offset(pud, vaddr);
	pte = pte_offset_kernel(pmd, vaddr);
	pkmap_page_table = pte;	
}

static void __devinit free_new_highpage(struct page *page)
{
	set_page_count(page, 1);
	__free_page(page);
	totalhigh_pages++;
}

void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro)
{
	if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) {
		ClearPageReserved(page);
		free_new_highpage(page);
	} else
		SetPageReserved(page);
}

static int add_one_highpage_hotplug(struct page *page, unsigned long pfn)
{
	free_new_highpage(page);
	totalram_pages++;
#ifdef CONFIG_FLATMEM
	max_mapnr = max(pfn, max_mapnr);
#endif
	num_physpages++;
	return 0;
}

/*
 * Not currently handling the NUMA case.
 * Assuming single node and all memory that
 * has been added dynamically that would be
 * onlined here is in HIGHMEM
 */
void online_page(struct page *page)
{
	ClearPageReserved(page);
	add_one_highpage_hotplug(page, page_to_pfn(page));
}


#ifdef CONFIG_NUMA
extern void set_highmem_pages_init(int);
#else
static void __init set_highmem_pages_init(int bad_ppro)
{
	int pfn;
	for (pfn = highstart_pfn; pfn < highend_pfn; pfn++)
		add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro);
	totalram_pages += totalhigh_pages;
}
#endif /* CONFIG_FLATMEM */

#else
#define kmap_init() do { } while (0)
#define permanent_kmaps_init(pgd_base) do { } while (0)
#define set_highmem_pages_init(bad_ppro) do { } while (0)
#endif /* CONFIG_HIGHMEM */

unsigned long long __PAGE_KERNEL = _PAGE_KERNEL;
EXPORT_SYMBOL(__PAGE_KERNEL);
unsigned long long __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;

#ifdef CONFIG_NUMA
extern void __init remap_numa_kva(void);
#else
#define remap_numa_kva() do {} while (0)
#endif

static void __init pagetable_init (void)
{
	unsigned long vaddr;
	pgd_t *pgd_base = swapper_pg_dir;

#ifdef CONFIG_X86_PAE
	int i;
	/* Init entries of the first-level page table to the zero page */
	for (i = 0; i < PTRS_PER_PGD; i++)
		set_pgd(pgd_base + i, __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
#endif

	/* Enable PSE if available */
	if (cpu_has_pse) {
		set_in_cr4(X86_CR4_PSE);
	}

	/* Enable PGE if available */
	if (cpu_has_pge) {
		set_in_cr4(X86_CR4_PGE);
		__PAGE_KERNEL |= _PAGE_GLOBAL;
		__PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
	}

	kernel_physical_mapping_init(pgd_base);
	remap_numa_kva();

	/*
	 * Fixed mappings, only the page table structure has to be
	 * created - mappings will be set by set_fixmap():
	 */
	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
	page_table_range_init(vaddr, 0, pgd_base);

	permanent_kmaps_init(pgd_base);

#ifdef CONFIG_X86_PAE
	/*
	 * Add low memory identity-mappings - SMP needs it when
	 * starting up on an AP from real-mode. In the non-PAE
	 * case we already have these mappings through head.S.
	 * All user-space mappings are explicitly cleared after
	 * SMP startup.
	 */
	set_pgd(&pgd_base[0], pgd_base[USER_PTRS_PER_PGD]);
#endif
}

#ifdef CONFIG_SOFTWARE_SUSPEND
/*
 * Swap suspend & friends need this for resume because things like the intel-agp
 * driver might have split up a kernel 4MB mapping.
 */
char __nosavedata swsusp_pg_dir[PAGE_SIZE]
	__attribute__ ((aligned (PAGE_SIZE)));

static inline void save_pg_dir(void)
{
	memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
}
#else
static inline void save_pg_dir(void)
{
}
#endif

void zap_low_mappings (void)
{
	int i;

	save_pg_dir();

	/*
	 * Zap initial low-memory mappings.
	 *
	 * Note that "pgd_clear()" doesn't do it for
	 * us, because pgd_clear() is a no-op on i386.
	 */
	for (i = 0; i < USER_PTRS_PER_PGD; i++)
#ifdef CONFIG_X86_PAE
		set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
#else
		set_pgd(swapper_pg_dir+i, __pgd(0));
#endif
	flush_tlb_all();
}

static int disable_nx __initdata = 0;
u64 __supported_pte_mask __read_mostly = ~_PAGE_NX;

/*
 * noexec = on|off
 *
 * Control non executable mappings.
 *
 * on      Enable
 * off     Disable
 */
void __init noexec_setup(const char *str)
{
	if (!strncmp(str, "on",2) && cpu_has_nx) {
		__supported_pte_mask |= _PAGE_NX;
		disable_nx = 0;
	} else if (!strncmp(str,"off",3)) {
		disable_nx = 1;
		__supported_pte_mask &= ~_PAGE_NX;
	}
}

int nx_enabled = 0;
#ifdef CONFIG_X86_PAE

static void __init set_nx(void)
{
	unsigned int v[4], l, h;

	if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
		cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
		if ((v[3] & (1 << 20)) && !disable_nx) {
			rdmsr(MSR_EFER, l, h);
			l |= EFER_NX;
			wrmsr(MSR_EFER, l, h);
			nx_enabled = 1;
			__supported_pte_mask |= _PAGE_NX;
		}
	}
}

/*
 * Enables/disables executability of a given kernel page and
 * returns the previous setting.
 */
int __init set_kernel_exec(unsigned long vaddr, int enable)
{
	pte_t *pte;
	int ret = 1;

	if (!nx_enabled)
		goto out;

	pte = lookup_address(vaddr);
	BUG_ON(!pte);

	if (!pte_exec_kernel(*pte))
		ret = 0;

	if (enable)
		pte->pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
	else
		pte->pte_high |= 1 << (_PAGE_BIT_NX - 32);
	__flush_tlb_all();
out:
	return ret;
}

#endif

/*
 * paging_init() sets up the page tables - note that the first 8MB are
 * already mapped by head.S.
 *
 * This routines also unmaps the page at virtual kernel address 0, so
 * that we can trap those pesky NULL-reference errors in the kernel.
 */
void __init paging_init(void)
{
#ifdef CONFIG_X86_PAE
	set_nx();
	if (nx_enabled)
		printk("NX (Execute Disable) protection: active\n");
#endif

	pagetable_init();

	load_cr3(swapper_pg_dir);

#ifdef CONFIG_X86_PAE
	/*
	 * We will bail out later - printk doesn't work right now so
	 * the user would just see a hanging kernel.
	 */
	if (cpu_has_pae)
		set_in_cr4(X86_CR4_PAE);
#endif
	__flush_tlb_all();

	kmap_init();
}

/*
 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 * and also on some strange 486's (NexGen etc.). All 586+'s are OK. This
 * used to involve black magic jumps to work around some nasty CPU bugs,
 * but fortunately the switch to using exceptions got rid of all that.
 */

static void __init test_wp_bit(void)
{
	printk("Checking if this processor honours the WP bit even in supervisor mode... ");

	/* Any page-aligned address will do, the test is non-destructive */
	__set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
	boot_cpu_data.wp_works_ok = do_test_wp_bit();
	clear_fixmap(FIX_WP_TEST);

	if (!boot_cpu_data.wp_works_ok) {
		printk("No.\n");
#ifdef CONFIG_X86_WP_WORKS_OK
		panic("This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
#endif
	} else {
		printk("Ok.\n");
	}
}

static void __init set_max_mapnr_init(void)
{
#ifdef CONFIG_HIGHMEM
	num_physpages = highend_pfn;
#else
	num_physpages = max_low_pfn;
#endif
#ifdef CONFIG_FLATMEM
	max_mapnr = num_physpages;
#endif
}

static struct kcore_list kcore_mem, kcore_vmalloc; 

void __init mem_init(void)
{
	extern int ppro_with_ram_bug(void);
	int codesize, reservedpages, datasize, initsize;
	int tmp;
	int bad_ppro;

#ifdef CONFIG_FLATMEM
	if (!mem_map)
		BUG();
#endif
	
	bad_ppro = ppro_with_ram_bug();

#ifdef CONFIG_HIGHMEM
	/* check that fixmap and pkmap do not overlap */
	if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
		printk(KERN_ERR "fixmap and kmap areas overlap - this will crash\n");
		printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n",
				PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, FIXADDR_START);
		BUG();
	}
#endif
 
	set_max_mapnr_init();

#ifdef CONFIG_HIGHMEM
	high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
#else
	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
#endif

	/* this will put all low memory onto the freelists */
	totalram_pages += free_all_bootmem();

	reservedpages = 0;
	for (tmp = 0; tmp < max_low_pfn; tmp++)
		/*
		 * Only count reserved RAM pages
		 */
		if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
			reservedpages++;

	set_highmem_pages_init(bad_ppro);

	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
	datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;

	kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT); 
	kclist_add(&kcore_vmalloc, (void *)VMALLOC_START, 
		   VMALLOC_END-VMALLOC_START);

	printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
		(unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
		num_physpages << (PAGE_SHIFT-10),
		codesize >> 10,
		reservedpages << (PAGE_SHIFT-10),
		datasize >> 10,
		initsize >> 10,
		(unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
	       );

#ifdef CONFIG_X86_PAE
	if (!cpu_has_pae)
		panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");
#endif
	if (boot_cpu_data.wp_works_ok < 0)
		test_wp_bit();

	/*
	 * Subtle. SMP is doing it's boot stuff late (because it has to
	 * fork idle threads) - but it also needs low mappings for the
	 * protected-mode entry to work. We zap these entries only after
	 * the WP-bit has been tested.
	 */
#ifndef CONFIG_SMP
	zap_low_mappings();
#endif
}

/*
 * this is for the non-NUMA, single node SMP system case.
 * Specifically, in the case of x86, we will always add
 * memory to the highmem for now.
 */
#ifndef CONFIG_NEED_MULTIPLE_NODES
int add_memory(u64 start, u64 size)
{
	struct pglist_data *pgdata = &contig_page_data;
	struct zone *zone = pgdata->node_zones + MAX_NR_ZONES-1;
	unsigned long start_pfn = start >> PAGE_SHIFT;
	unsigned long nr_pages = size >> PAGE_SHIFT;

	return __add_pages(zone, start_pfn, nr_pages);
}

int remove_memory(u64 start, u64 size)
{
	return -EINVAL;
}
#endif

kmem_cache_t *pgd_cache;
kmem_cache_t *pmd_cache;

void __init pgtable_cache_init(void)
{
	if (PTRS_PER_PMD > 1) {
		pmd_cache = kmem_cache_create("pmd",
					PTRS_PER_PMD*sizeof(pmd_t),
					PTRS_PER_PMD*sizeof(pmd_t),
					0,
					pmd_ctor,
					NULL);
		if (!pmd_cache)
			panic("pgtable_cache_init(): cannot create pmd cache");
	}
	pgd_cache = kmem_cache_create("pgd",
				PTRS_PER_PGD*sizeof(pgd_t),
				PTRS_PER_PGD*sizeof(pgd_t),
				0,
				pgd_ctor,
				PTRS_PER_PMD == 1 ? pgd_dtor : NULL);
	if (!pgd_cache)
		panic("pgtable_cache_init(): Cannot create pgd cache");
}

/*
 * This function cannot be __init, since exceptions don't work in that
 * section.  Put this after the callers, so that it cannot be inlined.
 */
static int noinline do_test_wp_bit(void)
{
	char tmp_reg;
	int flag;

	__asm__ __volatile__(
		"	movb %0,%1	\n"
		"1:	movb %1,%0	\n"
		"	xorl %2,%2	\n"
		"2:			\n"
		".section __ex_table,\"a\"\n"
		"	.align 4	\n"
		"	.long 1b,2b	\n"
		".previous		\n"
		:"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
		 "=q" (tmp_reg),
		 "=r" (flag)
		:"2" (1)
		:"memory");
	
	return flag;
}

void free_initmem(void)
{
	unsigned long addr;

	addr = (unsigned long)(&__init_begin);
	for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
		ClearPageReserved(virt_to_page(addr));
		set_page_count(virt_to_page(addr), 1);
		memset((void *)addr, 0xcc, PAGE_SIZE);
		free_page(addr);
		totalram_pages++;
	}
	printk (KERN_INFO "Freeing unused kernel memory: %dk freed\n", (__init_end - __init_begin) >> 10);
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
	if (start < end)
		printk (KERN_INFO "Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
	for (; start < end; start += PAGE_SIZE) {
		ClearPageReserved(virt_to_page(start));
		set_page_count(virt_to_page(start), 1);
		free_page(start);
		totalram_pages++;
	}
}
#endif
OpenPOWER on IntegriCloud