3 * Copyright (C) 1995 Linus Torvalds
5 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
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>
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>
34 #include <asm/bios_ebda.h>
35 #include <asm/processor.h>
36 #include <asm/system.h>
37 #include <asm/uaccess.h>
38 #include <asm/pgtable.h>
40 #include <asm/fixmap.h>
45 #include <asm/tlbflush.h>
46 #include <asm/pgalloc.h>
47 #include <asm/sections.h>
48 #include <asm/paravirt.h>
49 #include <asm/setup.h>
50 #include <asm/cacheflush.h>
53 unsigned int __VMALLOC_RESERVE
= 128 << 20;
55 unsigned long max_low_pfn_mapped
;
56 unsigned long max_pfn_mapped
;
58 DEFINE_PER_CPU(struct mmu_gather
, mmu_gathers
);
59 unsigned long highstart_pfn
, highend_pfn
;
61 static noinline
int do_test_wp_bit(void);
64 static unsigned long __initdata table_start
;
65 static unsigned long __meminitdata table_end
;
66 static unsigned long __meminitdata table_top
;
68 static int __initdata after_init_bootmem
;
70 static __init
void *alloc_low_page(unsigned long *phys
)
72 unsigned long pfn
= table_end
++;
76 panic("alloc_low_page: ran out of memory");
78 adr
= __va(pfn
* PAGE_SIZE
);
79 memset(adr
, 0, PAGE_SIZE
);
80 *phys
= pfn
* PAGE_SIZE
;
85 * Creates a middle page table and puts a pointer to it in the
86 * given global directory entry. This only returns the gd entry
87 * in non-PAE compilation mode, since the middle layer is folded.
89 static pmd_t
* __init
one_md_table_init(pgd_t
*pgd
)
96 if (!(pgd_val(*pgd
) & _PAGE_PRESENT
)) {
97 if (after_init_bootmem
)
98 pmd_table
= (pmd_t
*)alloc_bootmem_low_pages(PAGE_SIZE
);
100 pmd_table
= (pmd_t
*)alloc_low_page(&phys
);
101 paravirt_alloc_pmd(&init_mm
, __pa(pmd_table
) >> PAGE_SHIFT
);
102 set_pgd(pgd
, __pgd(__pa(pmd_table
) | _PAGE_PRESENT
));
103 pud
= pud_offset(pgd
, 0);
104 BUG_ON(pmd_table
!= pmd_offset(pud
, 0));
107 pud
= pud_offset(pgd
, 0);
108 pmd_table
= pmd_offset(pud
, 0);
114 * Create a page table and place a pointer to it in a middle page
117 static pte_t
* __init
one_page_table_init(pmd_t
*pmd
)
119 if (!(pmd_val(*pmd
) & _PAGE_PRESENT
)) {
120 pte_t
*page_table
= NULL
;
122 if (after_init_bootmem
) {
123 #ifdef CONFIG_DEBUG_PAGEALLOC
124 page_table
= (pte_t
*) alloc_bootmem_pages(PAGE_SIZE
);
128 (pte_t
*)alloc_bootmem_low_pages(PAGE_SIZE
);
131 page_table
= (pte_t
*)alloc_low_page(&phys
);
134 paravirt_alloc_pte(&init_mm
, __pa(page_table
) >> PAGE_SHIFT
);
135 set_pmd(pmd
, __pmd(__pa(page_table
) | _PAGE_TABLE
));
136 BUG_ON(page_table
!= pte_offset_kernel(pmd
, 0));
139 return pte_offset_kernel(pmd
, 0);
143 * This function initializes a certain range of kernel virtual memory
144 * with new bootmem page tables, everywhere page tables are missing in
147 * NOTE: The pagetables are allocated contiguous on the physical space
148 * so we can cache the place of the first one and move around without
149 * checking the pgd every time.
152 page_table_range_init(unsigned long start
, unsigned long end
, pgd_t
*pgd_base
)
154 int pgd_idx
, pmd_idx
;
160 pgd_idx
= pgd_index(vaddr
);
161 pmd_idx
= pmd_index(vaddr
);
162 pgd
= pgd_base
+ pgd_idx
;
164 for ( ; (pgd_idx
< PTRS_PER_PGD
) && (vaddr
!= end
); pgd
++, pgd_idx
++) {
165 pmd
= one_md_table_init(pgd
);
166 pmd
= pmd
+ pmd_index(vaddr
);
167 for (; (pmd_idx
< PTRS_PER_PMD
) && (vaddr
!= end
);
169 one_page_table_init(pmd
);
177 static inline int is_kernel_text(unsigned long addr
)
179 if (addr
>= PAGE_OFFSET
&& addr
<= (unsigned long)__init_end
)
185 * This maps the physical memory to kernel virtual address space, a total
186 * of max_low_pfn pages, by creating page tables starting from address
189 static void __init
kernel_physical_mapping_init(pgd_t
*pgd_base
,
190 unsigned long start_pfn
,
191 unsigned long end_pfn
,
194 int pgd_idx
, pmd_idx
, pte_ofs
;
199 unsigned pages_2m
, pages_4k
;
203 * First iteration will setup identity mapping using large/small pages
204 * based on use_pse, with other attributes same as set by
205 * the early code in head_32.S
207 * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
208 * as desired for the kernel identity mapping.
210 * This two pass mechanism conforms to the TLB app note which says:
212 * "Software should not write to a paging-structure entry in a way
213 * that would change, for any linear address, both the page size
214 * and either the page frame or attributes."
222 pages_2m
= pages_4k
= 0;
224 pgd_idx
= pgd_index((pfn
<<PAGE_SHIFT
) + PAGE_OFFSET
);
225 pgd
= pgd_base
+ pgd_idx
;
226 for (; pgd_idx
< PTRS_PER_PGD
; pgd
++, pgd_idx
++) {
227 pmd
= one_md_table_init(pgd
);
231 #ifdef CONFIG_X86_PAE
232 pmd_idx
= pmd_index((pfn
<<PAGE_SHIFT
) + PAGE_OFFSET
);
237 for (; pmd_idx
< PTRS_PER_PMD
&& pfn
< end_pfn
;
239 unsigned int addr
= pfn
* PAGE_SIZE
+ PAGE_OFFSET
;
242 * Map with big pages if possible, otherwise
243 * create normal page tables:
247 pgprot_t prot
= PAGE_KERNEL_LARGE
;
249 * first pass will use the same initial
250 * identity mapping attribute + _PAGE_PSE.
253 __pgprot(PTE_IDENT_ATTR
|
256 addr2
= (pfn
+ PTRS_PER_PTE
-1) * PAGE_SIZE
+
257 PAGE_OFFSET
+ PAGE_SIZE
-1;
259 if (is_kernel_text(addr
) ||
260 is_kernel_text(addr2
))
261 prot
= PAGE_KERNEL_LARGE_EXEC
;
264 if (mapping_iter
== 1)
265 set_pmd(pmd
, pfn_pmd(pfn
, init_prot
));
267 set_pmd(pmd
, pfn_pmd(pfn
, prot
));
272 pte
= one_page_table_init(pmd
);
274 pte_ofs
= pte_index((pfn
<<PAGE_SHIFT
) + PAGE_OFFSET
);
276 for (; pte_ofs
< PTRS_PER_PTE
&& pfn
< end_pfn
;
277 pte
++, pfn
++, pte_ofs
++, addr
+= PAGE_SIZE
) {
278 pgprot_t prot
= PAGE_KERNEL
;
280 * first pass will use the same initial
281 * identity mapping attribute.
283 pgprot_t init_prot
= __pgprot(PTE_IDENT_ATTR
);
285 if (is_kernel_text(addr
))
286 prot
= PAGE_KERNEL_EXEC
;
289 if (mapping_iter
== 1)
290 set_pte(pte
, pfn_pte(pfn
, init_prot
));
292 set_pte(pte
, pfn_pte(pfn
, prot
));
296 if (mapping_iter
== 1) {
298 * update direct mapping page count only in the first
301 update_page_count(PG_LEVEL_2M
, pages_2m
);
302 update_page_count(PG_LEVEL_4K
, pages_4k
);
305 * local global flush tlb, which will flush the previous
306 * mappings present in both small and large page TLB's.
311 * Second iteration will set the actual desired PTE attributes.
319 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
320 * is valid. The argument is a physical page number.
323 * On x86, access has to be given to the first megabyte of ram because that area
324 * contains bios code and data regions used by X and dosemu and similar apps.
325 * Access has to be given to non-kernel-ram areas as well, these contain the PCI
326 * mmio resources as well as potential bios/acpi data regions.
328 int devmem_is_allowed(unsigned long pagenr
)
332 if (!page_is_ram(pagenr
))
337 #ifdef CONFIG_HIGHMEM
341 static inline pte_t
*kmap_get_fixmap_pte(unsigned long vaddr
)
343 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr
),
344 vaddr
), vaddr
), vaddr
);
347 static void __init
kmap_init(void)
349 unsigned long kmap_vstart
;
352 * Cache the first kmap pte:
354 kmap_vstart
= __fix_to_virt(FIX_KMAP_BEGIN
);
355 kmap_pte
= kmap_get_fixmap_pte(kmap_vstart
);
357 kmap_prot
= PAGE_KERNEL
;
360 static void __init
permanent_kmaps_init(pgd_t
*pgd_base
)
369 page_table_range_init(vaddr
, vaddr
+ PAGE_SIZE
*LAST_PKMAP
, pgd_base
);
371 pgd
= swapper_pg_dir
+ pgd_index(vaddr
);
372 pud
= pud_offset(pgd
, vaddr
);
373 pmd
= pmd_offset(pud
, vaddr
);
374 pte
= pte_offset_kernel(pmd
, vaddr
);
375 pkmap_page_table
= pte
;
378 static void __init
add_one_highpage_init(struct page
*page
, int pfn
)
380 ClearPageReserved(page
);
381 init_page_count(page
);
386 struct add_highpages_data
{
387 unsigned long start_pfn
;
388 unsigned long end_pfn
;
391 static int __init
add_highpages_work_fn(unsigned long start_pfn
,
392 unsigned long end_pfn
, void *datax
)
396 unsigned long final_start_pfn
, final_end_pfn
;
397 struct add_highpages_data
*data
;
399 data
= (struct add_highpages_data
*)datax
;
401 final_start_pfn
= max(start_pfn
, data
->start_pfn
);
402 final_end_pfn
= min(end_pfn
, data
->end_pfn
);
403 if (final_start_pfn
>= final_end_pfn
)
406 for (node_pfn
= final_start_pfn
; node_pfn
< final_end_pfn
;
408 if (!pfn_valid(node_pfn
))
410 page
= pfn_to_page(node_pfn
);
411 add_one_highpage_init(page
, node_pfn
);
418 void __init
add_highpages_with_active_regions(int nid
, unsigned long start_pfn
,
419 unsigned long end_pfn
)
421 struct add_highpages_data data
;
423 data
.start_pfn
= start_pfn
;
424 data
.end_pfn
= end_pfn
;
426 work_with_active_regions(nid
, add_highpages_work_fn
, &data
);
430 static void __init
set_highmem_pages_init(void)
432 add_highpages_with_active_regions(0, highstart_pfn
, highend_pfn
);
434 totalram_pages
+= totalhigh_pages
;
436 #endif /* !CONFIG_NUMA */
439 # define kmap_init() do { } while (0)
440 # define permanent_kmaps_init(pgd_base) do { } while (0)
441 # define set_highmem_pages_init() do { } while (0)
442 #endif /* CONFIG_HIGHMEM */
444 void __init
native_pagetable_setup_start(pgd_t
*base
)
446 unsigned long pfn
, va
;
453 * Remove any mappings which extend past the end of physical
454 * memory from the boot time page table:
456 for (pfn
= max_low_pfn
+ 1; pfn
< 1<<(32-PAGE_SHIFT
); pfn
++) {
457 va
= PAGE_OFFSET
+ (pfn
<<PAGE_SHIFT
);
458 pgd
= base
+ pgd_index(va
);
459 if (!pgd_present(*pgd
))
462 pud
= pud_offset(pgd
, va
);
463 pmd
= pmd_offset(pud
, va
);
464 if (!pmd_present(*pmd
))
467 pte
= pte_offset_kernel(pmd
, va
);
468 if (!pte_present(*pte
))
471 pte_clear(NULL
, va
, pte
);
473 paravirt_alloc_pmd(&init_mm
, __pa(base
) >> PAGE_SHIFT
);
476 void __init
native_pagetable_setup_done(pgd_t
*base
)
481 * Build a proper pagetable for the kernel mappings. Up until this
482 * point, we've been running on some set of pagetables constructed by
485 * If we're booting on native hardware, this will be a pagetable
486 * constructed in arch/x86/kernel/head_32.S. The root of the
487 * pagetable will be swapper_pg_dir.
489 * If we're booting paravirtualized under a hypervisor, then there are
490 * more options: we may already be running PAE, and the pagetable may
491 * or may not be based in swapper_pg_dir. In any case,
492 * paravirt_pagetable_setup_start() will set up swapper_pg_dir
493 * appropriately for the rest of the initialization to work.
495 * In general, pagetable_init() assumes that the pagetable may already
496 * be partially populated, and so it avoids stomping on any existing
499 static void __init
early_ioremap_page_table_range_init(pgd_t
*pgd_base
)
501 unsigned long vaddr
, end
;
504 * Fixed mappings, only the page table structure has to be
505 * created - mappings will be set by set_fixmap():
507 early_ioremap_clear();
508 vaddr
= __fix_to_virt(__end_of_fixed_addresses
- 1) & PMD_MASK
;
509 end
= (FIXADDR_TOP
+ PMD_SIZE
- 1) & PMD_MASK
;
510 page_table_range_init(vaddr
, end
, pgd_base
);
511 early_ioremap_reset();
514 static void __init
pagetable_init(void)
516 pgd_t
*pgd_base
= swapper_pg_dir
;
518 permanent_kmaps_init(pgd_base
);
521 #ifdef CONFIG_ACPI_SLEEP
523 * ACPI suspend needs this for resume, because things like the intel-agp
524 * driver might have split up a kernel 4MB mapping.
526 char swsusp_pg_dir
[PAGE_SIZE
]
527 __attribute__ ((aligned(PAGE_SIZE
)));
529 static inline void save_pg_dir(void)
531 memcpy(swsusp_pg_dir
, swapper_pg_dir
, PAGE_SIZE
);
533 #else /* !CONFIG_ACPI_SLEEP */
534 static inline void save_pg_dir(void)
537 #endif /* !CONFIG_ACPI_SLEEP */
539 void zap_low_mappings(void)
544 * Zap initial low-memory mappings.
546 * Note that "pgd_clear()" doesn't do it for
547 * us, because pgd_clear() is a no-op on i386.
549 for (i
= 0; i
< KERNEL_PGD_BOUNDARY
; i
++) {
550 #ifdef CONFIG_X86_PAE
551 set_pgd(swapper_pg_dir
+i
, __pgd(1 + __pa(empty_zero_page
)));
553 set_pgd(swapper_pg_dir
+i
, __pgd(0));
561 pteval_t __supported_pte_mask __read_mostly
= ~(_PAGE_NX
| _PAGE_GLOBAL
);
562 EXPORT_SYMBOL_GPL(__supported_pte_mask
);
564 #ifdef CONFIG_X86_PAE
566 static int disable_nx __initdata
;
571 * Control non executable mappings.
576 static int __init
noexec_setup(char *str
)
578 if (!str
|| !strcmp(str
, "on")) {
580 __supported_pte_mask
|= _PAGE_NX
;
584 if (!strcmp(str
, "off")) {
586 __supported_pte_mask
&= ~_PAGE_NX
;
594 early_param("noexec", noexec_setup
);
596 static void __init
set_nx(void)
598 unsigned int v
[4], l
, h
;
600 if (cpu_has_pae
&& (cpuid_eax(0x80000000) > 0x80000001)) {
601 cpuid(0x80000001, &v
[0], &v
[1], &v
[2], &v
[3]);
603 if ((v
[3] & (1 << 20)) && !disable_nx
) {
604 rdmsr(MSR_EFER
, l
, h
);
606 wrmsr(MSR_EFER
, l
, h
);
608 __supported_pte_mask
|= _PAGE_NX
;
614 /* user-defined highmem size */
615 static unsigned int highmem_pages
= -1;
618 * highmem=size forces highmem to be exactly 'size' bytes.
619 * This works even on boxes that have no highmem otherwise.
620 * This also works to reduce highmem size on bigger boxes.
622 static int __init
parse_highmem(char *arg
)
627 highmem_pages
= memparse(arg
, &arg
) >> PAGE_SHIFT
;
630 early_param("highmem", parse_highmem
);
633 * Determine low and high memory ranges:
635 void __init
find_low_pfn_range(void)
637 /* it could update max_pfn */
639 /* max_low_pfn is 0, we already have early_res support */
641 max_low_pfn
= max_pfn
;
642 if (max_low_pfn
> MAXMEM_PFN
) {
643 if (highmem_pages
== -1)
644 highmem_pages
= max_pfn
- MAXMEM_PFN
;
645 if (highmem_pages
+ MAXMEM_PFN
< max_pfn
)
646 max_pfn
= MAXMEM_PFN
+ highmem_pages
;
647 if (highmem_pages
+ MAXMEM_PFN
> max_pfn
) {
648 printk(KERN_WARNING
"only %luMB highmem pages "
649 "available, ignoring highmem size of %uMB.\n",
650 pages_to_mb(max_pfn
- MAXMEM_PFN
),
651 pages_to_mb(highmem_pages
));
654 max_low_pfn
= MAXMEM_PFN
;
655 #ifndef CONFIG_HIGHMEM
656 /* Maximum memory usable is what is directly addressable */
657 printk(KERN_WARNING
"Warning only %ldMB will be used.\n",
659 if (max_pfn
> MAX_NONPAE_PFN
)
661 "Use a HIGHMEM64G enabled kernel.\n");
663 printk(KERN_WARNING
"Use a HIGHMEM enabled kernel.\n");
664 max_pfn
= MAXMEM_PFN
;
665 #else /* !CONFIG_HIGHMEM */
666 #ifndef CONFIG_HIGHMEM64G
667 if (max_pfn
> MAX_NONPAE_PFN
) {
668 max_pfn
= MAX_NONPAE_PFN
;
669 printk(KERN_WARNING
"Warning only 4GB will be used."
670 "Use a HIGHMEM64G enabled kernel.\n");
672 #endif /* !CONFIG_HIGHMEM64G */
673 #endif /* !CONFIG_HIGHMEM */
675 if (highmem_pages
== -1)
677 #ifdef CONFIG_HIGHMEM
678 if (highmem_pages
>= max_pfn
) {
679 printk(KERN_ERR
"highmem size specified (%uMB) is "
680 "bigger than pages available (%luMB)!.\n",
681 pages_to_mb(highmem_pages
),
682 pages_to_mb(max_pfn
));
686 if (max_low_pfn
- highmem_pages
<
687 64*1024*1024/PAGE_SIZE
){
688 printk(KERN_ERR
"highmem size %uMB results in "
689 "smaller than 64MB lowmem, ignoring it.\n"
690 , pages_to_mb(highmem_pages
));
693 max_low_pfn
-= highmem_pages
;
697 printk(KERN_ERR
"ignoring highmem size on non-highmem"
703 #ifndef CONFIG_NEED_MULTIPLE_NODES
704 void __init
initmem_init(unsigned long start_pfn
,
705 unsigned long end_pfn
)
707 #ifdef CONFIG_HIGHMEM
708 highstart_pfn
= highend_pfn
= max_pfn
;
709 if (max_pfn
> max_low_pfn
)
710 highstart_pfn
= max_low_pfn
;
711 memory_present(0, 0, highend_pfn
);
712 e820_register_active_regions(0, 0, highend_pfn
);
713 printk(KERN_NOTICE
"%ldMB HIGHMEM available.\n",
714 pages_to_mb(highend_pfn
- highstart_pfn
));
715 num_physpages
= highend_pfn
;
716 high_memory
= (void *) __va(highstart_pfn
* PAGE_SIZE
- 1) + 1;
718 memory_present(0, 0, max_low_pfn
);
719 e820_register_active_regions(0, 0, max_low_pfn
);
720 num_physpages
= max_low_pfn
;
721 high_memory
= (void *) __va(max_low_pfn
* PAGE_SIZE
- 1) + 1;
723 #ifdef CONFIG_FLATMEM
724 max_mapnr
= num_physpages
;
726 printk(KERN_NOTICE
"%ldMB LOWMEM available.\n",
727 pages_to_mb(max_low_pfn
));
729 setup_bootmem_allocator();
731 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
733 static void __init
zone_sizes_init(void)
735 unsigned long max_zone_pfns
[MAX_NR_ZONES
];
736 memset(max_zone_pfns
, 0, sizeof(max_zone_pfns
));
737 max_zone_pfns
[ZONE_DMA
] =
738 virt_to_phys((char *)MAX_DMA_ADDRESS
) >> PAGE_SHIFT
;
739 max_zone_pfns
[ZONE_NORMAL
] = max_low_pfn
;
740 #ifdef CONFIG_HIGHMEM
741 max_zone_pfns
[ZONE_HIGHMEM
] = highend_pfn
;
744 free_area_init_nodes(max_zone_pfns
);
747 void __init
setup_bootmem_allocator(void)
750 unsigned long bootmap_size
, bootmap
;
752 * Initialize the boot-time allocator (with low memory only):
754 bootmap_size
= bootmem_bootmap_pages(max_low_pfn
)<<PAGE_SHIFT
;
755 bootmap
= find_e820_area(min_low_pfn
<<PAGE_SHIFT
,
756 max_pfn_mapped
<<PAGE_SHIFT
, bootmap_size
,
759 panic("Cannot find bootmem map of size %ld\n", bootmap_size
);
760 reserve_early(bootmap
, bootmap
+ bootmap_size
, "BOOTMAP");
762 /* don't touch min_low_pfn */
763 bootmap_size
= init_bootmem_node(NODE_DATA(0), bootmap
>> PAGE_SHIFT
,
764 min_low_pfn
, max_low_pfn
);
765 printk(KERN_INFO
" mapped low ram: 0 - %08lx\n",
766 max_pfn_mapped
<<PAGE_SHIFT
);
767 printk(KERN_INFO
" low ram: %08lx - %08lx\n",
768 min_low_pfn
<<PAGE_SHIFT
, max_low_pfn
<<PAGE_SHIFT
);
769 printk(KERN_INFO
" bootmap %08lx - %08lx\n",
770 bootmap
, bootmap
+ bootmap_size
);
771 for_each_online_node(i
)
772 free_bootmem_with_active_regions(i
, max_low_pfn
);
773 early_res_to_bootmem(0, max_low_pfn
<<PAGE_SHIFT
);
775 after_init_bootmem
= 1;
778 static void __init
find_early_table_space(unsigned long end
, int use_pse
)
780 unsigned long puds
, pmds
, ptes
, tables
, start
;
782 puds
= (end
+ PUD_SIZE
- 1) >> PUD_SHIFT
;
783 tables
= PAGE_ALIGN(puds
* sizeof(pud_t
));
785 pmds
= (end
+ PMD_SIZE
- 1) >> PMD_SHIFT
;
786 tables
+= PAGE_ALIGN(pmds
* sizeof(pmd_t
));
791 extra
= end
- ((end
>>PMD_SHIFT
) << PMD_SHIFT
);
793 ptes
= (extra
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
795 ptes
= (end
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
797 tables
+= PAGE_ALIGN(ptes
* sizeof(pte_t
));
800 tables
+= PAGE_SIZE
* 2;
803 * RED-PEN putting page tables only on node 0 could
804 * cause a hotspot and fill up ZONE_DMA. The page tables
805 * need roughly 0.5KB per GB.
808 table_start
= find_e820_area(start
, max_pfn_mapped
<<PAGE_SHIFT
,
810 if (table_start
== -1UL)
811 panic("Cannot find space for the kernel page tables");
813 table_start
>>= PAGE_SHIFT
;
814 table_end
= table_start
;
815 table_top
= table_start
+ (tables
>>PAGE_SHIFT
);
817 printk(KERN_DEBUG
"kernel direct mapping tables up to %lx @ %lx-%lx\n",
818 end
, table_start
<< PAGE_SHIFT
,
819 (table_start
<< PAGE_SHIFT
) + tables
);
822 unsigned long __init_refok
init_memory_mapping(unsigned long start
,
825 pgd_t
*pgd_base
= swapper_pg_dir
;
826 unsigned long start_pfn
, end_pfn
;
827 unsigned long big_page_start
;
828 #ifdef CONFIG_DEBUG_PAGEALLOC
830 * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
831 * This will simplify cpa(), which otherwise needs to support splitting
832 * large pages into small in interrupt context, etc.
836 int use_pse
= cpu_has_pse
;
840 * Find space for the kernel direct mapping tables.
842 if (!after_init_bootmem
)
843 find_early_table_space(end
, use_pse
);
845 #ifdef CONFIG_X86_PAE
848 printk(KERN_INFO
"NX (Execute Disable) protection: active\n");
851 /* Enable PSE if available */
853 set_in_cr4(X86_CR4_PSE
);
855 /* Enable PGE if available */
857 set_in_cr4(X86_CR4_PGE
);
858 __supported_pte_mask
|= _PAGE_GLOBAL
;
862 * Don't use a large page for the first 2/4MB of memory
863 * because there are often fixed size MTRRs in there
864 * and overlapping MTRRs into large pages can cause
867 big_page_start
= PMD_SIZE
;
869 if (start
< big_page_start
) {
870 start_pfn
= start
>> PAGE_SHIFT
;
871 end_pfn
= min(big_page_start
>>PAGE_SHIFT
, end
>>PAGE_SHIFT
);
873 /* head is not big page alignment ? */
874 start_pfn
= start
>> PAGE_SHIFT
;
875 end_pfn
= ((start
+ (PMD_SIZE
- 1))>>PMD_SHIFT
)
876 << (PMD_SHIFT
- PAGE_SHIFT
);
878 if (start_pfn
< end_pfn
)
879 kernel_physical_mapping_init(pgd_base
, start_pfn
, end_pfn
, 0);
882 start_pfn
= ((start
+ (PMD_SIZE
- 1))>>PMD_SHIFT
)
883 << (PMD_SHIFT
- PAGE_SHIFT
);
884 if (start_pfn
< (big_page_start
>> PAGE_SHIFT
))
885 start_pfn
= big_page_start
>> PAGE_SHIFT
;
886 end_pfn
= (end
>>PMD_SHIFT
) << (PMD_SHIFT
- PAGE_SHIFT
);
887 if (start_pfn
< end_pfn
)
888 kernel_physical_mapping_init(pgd_base
, start_pfn
, end_pfn
,
891 /* tail is not big page alignment ? */
893 if (start_pfn
> (big_page_start
>>PAGE_SHIFT
)) {
894 end_pfn
= end
>> PAGE_SHIFT
;
895 if (start_pfn
< end_pfn
)
896 kernel_physical_mapping_init(pgd_base
, start_pfn
,
900 early_ioremap_page_table_range_init(pgd_base
);
902 load_cr3(swapper_pg_dir
);
906 if (!after_init_bootmem
)
907 reserve_early(table_start
<< PAGE_SHIFT
,
908 table_end
<< PAGE_SHIFT
, "PGTABLE");
910 if (!after_init_bootmem
)
911 early_memtest(start
, end
);
913 return end
>> PAGE_SHIFT
;
918 * paging_init() sets up the page tables - note that the first 8MB are
919 * already mapped by head.S.
921 * This routines also unmaps the page at virtual kernel address 0, so
922 * that we can trap those pesky NULL-reference errors in the kernel.
924 void __init
paging_init(void)
933 * NOTE: at this point the bootmem allocator is fully available.
940 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
941 * and also on some strange 486's. All 586+'s are OK. This used to involve
942 * black magic jumps to work around some nasty CPU bugs, but fortunately the
943 * switch to using exceptions got rid of all that.
945 static void __init
test_wp_bit(void)
948 "Checking if this processor honours the WP bit even in supervisor mode...");
950 /* Any page-aligned address will do, the test is non-destructive */
951 __set_fixmap(FIX_WP_TEST
, __pa(&swapper_pg_dir
), PAGE_READONLY
);
952 boot_cpu_data
.wp_works_ok
= do_test_wp_bit();
953 clear_fixmap(FIX_WP_TEST
);
955 if (!boot_cpu_data
.wp_works_ok
) {
956 printk(KERN_CONT
"No.\n");
957 #ifdef CONFIG_X86_WP_WORKS_OK
959 "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
962 printk(KERN_CONT
"Ok.\n");
966 static struct kcore_list kcore_mem
, kcore_vmalloc
;
968 void __init
mem_init(void)
970 int codesize
, reservedpages
, datasize
, initsize
;
973 start_periodic_check_for_corruption();
975 #ifdef CONFIG_FLATMEM
978 /* this will put all low memory onto the freelists */
979 totalram_pages
+= free_all_bootmem();
982 for (tmp
= 0; tmp
< max_low_pfn
; tmp
++)
984 * Only count reserved RAM pages:
986 if (page_is_ram(tmp
) && PageReserved(pfn_to_page(tmp
)))
989 set_highmem_pages_init();
991 codesize
= (unsigned long) &_etext
- (unsigned long) &_text
;
992 datasize
= (unsigned long) &_edata
- (unsigned long) &_etext
;
993 initsize
= (unsigned long) &__init_end
- (unsigned long) &__init_begin
;
995 kclist_add(&kcore_mem
, __va(0), max_low_pfn
<< PAGE_SHIFT
);
996 kclist_add(&kcore_vmalloc
, (void *)VMALLOC_START
,
997 VMALLOC_END
-VMALLOC_START
);
999 printk(KERN_INFO
"Memory: %luk/%luk available (%dk kernel code, "
1000 "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
1001 (unsigned long) nr_free_pages() << (PAGE_SHIFT
-10),
1002 num_physpages
<< (PAGE_SHIFT
-10),
1004 reservedpages
<< (PAGE_SHIFT
-10),
1007 (unsigned long) (totalhigh_pages
<< (PAGE_SHIFT
-10))
1010 printk(KERN_INFO
"virtual kernel memory layout:\n"
1011 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
1012 #ifdef CONFIG_HIGHMEM
1013 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
1015 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
1016 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
1017 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
1018 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
1019 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
1020 FIXADDR_START
, FIXADDR_TOP
,
1021 (FIXADDR_TOP
- FIXADDR_START
) >> 10,
1023 #ifdef CONFIG_HIGHMEM
1024 PKMAP_BASE
, PKMAP_BASE
+LAST_PKMAP
*PAGE_SIZE
,
1025 (LAST_PKMAP
*PAGE_SIZE
) >> 10,
1028 VMALLOC_START
, VMALLOC_END
,
1029 (VMALLOC_END
- VMALLOC_START
) >> 20,
1031 (unsigned long)__va(0), (unsigned long)high_memory
,
1032 ((unsigned long)high_memory
- (unsigned long)__va(0)) >> 20,
1034 (unsigned long)&__init_begin
, (unsigned long)&__init_end
,
1035 ((unsigned long)&__init_end
-
1036 (unsigned long)&__init_begin
) >> 10,
1038 (unsigned long)&_etext
, (unsigned long)&_edata
,
1039 ((unsigned long)&_edata
- (unsigned long)&_etext
) >> 10,
1041 (unsigned long)&_text
, (unsigned long)&_etext
,
1042 ((unsigned long)&_etext
- (unsigned long)&_text
) >> 10);
1044 #ifdef CONFIG_HIGHMEM
1045 BUG_ON(PKMAP_BASE
+ LAST_PKMAP
*PAGE_SIZE
> FIXADDR_START
);
1046 BUG_ON(VMALLOC_END
> PKMAP_BASE
);
1048 BUG_ON(VMALLOC_START
> VMALLOC_END
);
1049 BUG_ON((unsigned long)high_memory
> VMALLOC_START
);
1051 if (boot_cpu_data
.wp_works_ok
< 0)
1058 #ifdef CONFIG_MEMORY_HOTPLUG
1059 int arch_add_memory(int nid
, u64 start
, u64 size
)
1061 struct pglist_data
*pgdata
= NODE_DATA(nid
);
1062 struct zone
*zone
= pgdata
->node_zones
+ ZONE_HIGHMEM
;
1063 unsigned long start_pfn
= start
>> PAGE_SHIFT
;
1064 unsigned long nr_pages
= size
>> PAGE_SHIFT
;
1066 return __add_pages(zone
, start_pfn
, nr_pages
);
1071 * This function cannot be __init, since exceptions don't work in that
1072 * section. Put this after the callers, so that it cannot be inlined.
1074 static noinline
int do_test_wp_bit(void)
1079 __asm__
__volatile__(
1085 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST
)),
1094 #ifdef CONFIG_DEBUG_RODATA
1095 const int rodata_test_data
= 0xC3;
1096 EXPORT_SYMBOL_GPL(rodata_test_data
);
1098 void mark_rodata_ro(void)
1100 unsigned long start
= PFN_ALIGN(_text
);
1101 unsigned long size
= PFN_ALIGN(_etext
) - start
;
1103 #ifndef CONFIG_DYNAMIC_FTRACE
1104 /* Dynamic tracing modifies the kernel text section */
1105 set_pages_ro(virt_to_page(start
), size
>> PAGE_SHIFT
);
1106 printk(KERN_INFO
"Write protecting the kernel text: %luk\n",
1109 #ifdef CONFIG_CPA_DEBUG
1110 printk(KERN_INFO
"Testing CPA: Reverting %lx-%lx\n",
1112 set_pages_rw(virt_to_page(start
), size
>>PAGE_SHIFT
);
1114 printk(KERN_INFO
"Testing CPA: write protecting again\n");
1115 set_pages_ro(virt_to_page(start
), size
>>PAGE_SHIFT
);
1117 #endif /* CONFIG_DYNAMIC_FTRACE */
1120 size
= (unsigned long)__end_rodata
- start
;
1121 set_pages_ro(virt_to_page(start
), size
>> PAGE_SHIFT
);
1122 printk(KERN_INFO
"Write protecting the kernel read-only data: %luk\n",
1126 #ifdef CONFIG_CPA_DEBUG
1127 printk(KERN_INFO
"Testing CPA: undo %lx-%lx\n", start
, start
+ size
);
1128 set_pages_rw(virt_to_page(start
), size
>> PAGE_SHIFT
);
1130 printk(KERN_INFO
"Testing CPA: write protecting again\n");
1131 set_pages_ro(virt_to_page(start
), size
>> PAGE_SHIFT
);
1136 void free_init_pages(char *what
, unsigned long begin
, unsigned long end
)
1138 #ifdef CONFIG_DEBUG_PAGEALLOC
1140 * If debugging page accesses then do not free this memory but
1141 * mark them not present - any buggy init-section access will
1142 * create a kernel page fault:
1144 printk(KERN_INFO
"debug: unmapping init memory %08lx..%08lx\n",
1145 begin
, PAGE_ALIGN(end
));
1146 set_memory_np(begin
, (end
- begin
) >> PAGE_SHIFT
);
1151 * We just marked the kernel text read only above, now that
1152 * we are going to free part of that, we need to make that
1155 set_memory_rw(begin
, (end
- begin
) >> PAGE_SHIFT
);
1157 for (addr
= begin
; addr
< end
; addr
+= PAGE_SIZE
) {
1158 ClearPageReserved(virt_to_page(addr
));
1159 init_page_count(virt_to_page(addr
));
1160 memset((void *)addr
, POISON_FREE_INITMEM
, PAGE_SIZE
);
1164 printk(KERN_INFO
"Freeing %s: %luk freed\n", what
, (end
- begin
) >> 10);
1168 void free_initmem(void)
1170 free_init_pages("unused kernel memory",
1171 (unsigned long)(&__init_begin
),
1172 (unsigned long)(&__init_end
));
1175 #ifdef CONFIG_BLK_DEV_INITRD
1176 void free_initrd_mem(unsigned long start
, unsigned long end
)
1178 free_init_pages("initrd memory", start
, end
);
1182 int __init
reserve_bootmem_generic(unsigned long phys
, unsigned long len
,
1185 return reserve_bootmem(phys
, len
, flags
);