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/processor.h>
35 #include <asm/system.h>
36 #include <asm/uaccess.h>
37 #include <asm/pgtable.h>
39 #include <asm/fixmap.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>
51 unsigned int __VMALLOC_RESERVE
= 128 << 20;
53 unsigned long max_low_pfn_mapped
;
54 unsigned long max_pfn_mapped
;
56 DEFINE_PER_CPU(struct mmu_gather
, mmu_gathers
);
57 unsigned long highstart_pfn
, highend_pfn
;
59 static noinline
int do_test_wp_bit(void);
62 static unsigned long __initdata table_start
;
63 static unsigned long __meminitdata table_end
;
64 static unsigned long __meminitdata table_top
;
66 static int __initdata after_init_bootmem
;
68 static __init
void *alloc_low_page(unsigned long *phys
)
70 unsigned long pfn
= table_end
++;
74 panic("alloc_low_page: ran out of memory");
76 adr
= __va(pfn
* PAGE_SIZE
);
77 memset(adr
, 0, PAGE_SIZE
);
78 *phys
= pfn
* PAGE_SIZE
;
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.
87 static pmd_t
* __init
one_md_table_init(pgd_t
*pgd
)
94 if (!(pgd_val(*pgd
) & _PAGE_PRESENT
)) {
95 if (after_init_bootmem
)
96 pmd_table
= (pmd_t
*)alloc_bootmem_low_pages(PAGE_SIZE
);
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));
105 pud
= pud_offset(pgd
, 0);
106 pmd_table
= pmd_offset(pud
, 0);
112 * Create a page table and place a pointer to it in a middle page
115 static pte_t
* __init
one_page_table_init(pmd_t
*pmd
)
117 if (!(pmd_val(*pmd
) & _PAGE_PRESENT
)) {
118 pte_t
*page_table
= NULL
;
120 if (after_init_bootmem
) {
121 #ifdef CONFIG_DEBUG_PAGEALLOC
122 page_table
= (pte_t
*) alloc_bootmem_pages(PAGE_SIZE
);
126 (pte_t
*)alloc_bootmem_low_pages(PAGE_SIZE
);
129 page_table
= (pte_t
*)alloc_low_page(&phys
);
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));
137 return pte_offset_kernel(pmd
, 0);
141 * This function initializes a certain range of kernel virtual memory
142 * with new bootmem page tables, everywhere page tables are missing in
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.
150 page_table_range_init(unsigned long start
, unsigned long end
, pgd_t
*pgd_base
)
152 int pgd_idx
, pmd_idx
;
158 pgd_idx
= pgd_index(vaddr
);
159 pmd_idx
= pmd_index(vaddr
);
160 pgd
= pgd_base
+ pgd_idx
;
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
);
167 one_page_table_init(pmd
);
175 static inline int is_kernel_text(unsigned long addr
)
177 if (addr
>= PAGE_OFFSET
&& addr
<= (unsigned long)__init_end
)
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
187 static void __init
kernel_physical_mapping_init(pgd_t
*pgd_base
,
188 unsigned long start_pfn
,
189 unsigned long end_pfn
,
192 int pgd_idx
, pmd_idx
, pte_ofs
;
197 unsigned pages_2m
= 0, pages_4k
= 0;
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
);
210 #ifdef CONFIG_X86_PAE
211 pmd_idx
= pmd_index((pfn
<<PAGE_SHIFT
) + PAGE_OFFSET
);
216 for (; pmd_idx
< PTRS_PER_PMD
&& pfn
< end_pfn
;
218 unsigned int addr
= pfn
* PAGE_SIZE
+ PAGE_OFFSET
;
221 * Map with big pages if possible, otherwise
222 * create normal page tables:
226 pgprot_t prot
= PAGE_KERNEL_LARGE
;
228 addr2
= (pfn
+ PTRS_PER_PTE
-1) * PAGE_SIZE
+
229 PAGE_OFFSET
+ PAGE_SIZE
-1;
231 if (is_kernel_text(addr
) ||
232 is_kernel_text(addr2
))
233 prot
= PAGE_KERNEL_LARGE_EXEC
;
236 set_pmd(pmd
, pfn_pmd(pfn
, prot
));
241 pte
= one_page_table_init(pmd
);
243 pte_ofs
= pte_index((pfn
<<PAGE_SHIFT
) + PAGE_OFFSET
);
245 for (; pte_ofs
< PTRS_PER_PTE
&& pfn
< end_pfn
;
246 pte
++, pfn
++, pte_ofs
++, addr
+= PAGE_SIZE
) {
247 pgprot_t prot
= PAGE_KERNEL
;
249 if (is_kernel_text(addr
))
250 prot
= PAGE_KERNEL_EXEC
;
253 set_pte(pte
, pfn_pte(pfn
, prot
));
257 update_page_count(PG_LEVEL_2M
, pages_2m
);
258 update_page_count(PG_LEVEL_4K
, pages_4k
);
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.
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.
271 int devmem_is_allowed(unsigned long pagenr
)
275 if (!page_is_ram(pagenr
))
280 #ifdef CONFIG_HIGHMEM
284 static inline pte_t
*kmap_get_fixmap_pte(unsigned long vaddr
)
286 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr
),
287 vaddr
), vaddr
), vaddr
);
290 static void __init
kmap_init(void)
292 unsigned long kmap_vstart
;
295 * Cache the first kmap pte:
297 kmap_vstart
= __fix_to_virt(FIX_KMAP_BEGIN
);
298 kmap_pte
= kmap_get_fixmap_pte(kmap_vstart
);
300 kmap_prot
= PAGE_KERNEL
;
303 static void __init
permanent_kmaps_init(pgd_t
*pgd_base
)
312 page_table_range_init(vaddr
, vaddr
+ PAGE_SIZE
*LAST_PKMAP
, pgd_base
);
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
;
321 static void __init
add_one_highpage_init(struct page
*page
, int pfn
)
323 ClearPageReserved(page
);
324 init_page_count(page
);
329 struct add_highpages_data
{
330 unsigned long start_pfn
;
331 unsigned long end_pfn
;
334 static int __init
add_highpages_work_fn(unsigned long start_pfn
,
335 unsigned long end_pfn
, void *datax
)
339 unsigned long final_start_pfn
, final_end_pfn
;
340 struct add_highpages_data
*data
;
342 data
= (struct add_highpages_data
*)datax
;
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
)
349 for (node_pfn
= final_start_pfn
; node_pfn
< final_end_pfn
;
351 if (!pfn_valid(node_pfn
))
353 page
= pfn_to_page(node_pfn
);
354 add_one_highpage_init(page
, node_pfn
);
361 void __init
add_highpages_with_active_regions(int nid
, unsigned long start_pfn
,
362 unsigned long end_pfn
)
364 struct add_highpages_data data
;
366 data
.start_pfn
= start_pfn
;
367 data
.end_pfn
= end_pfn
;
369 work_with_active_regions(nid
, add_highpages_work_fn
, &data
);
373 static void __init
set_highmem_pages_init(void)
375 add_highpages_with_active_regions(0, highstart_pfn
, highend_pfn
);
377 totalram_pages
+= totalhigh_pages
;
379 #endif /* !CONFIG_NUMA */
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 */
387 void __init
native_pagetable_setup_start(pgd_t
*base
)
389 unsigned long pfn
, va
;
396 * Remove any mappings which extend past the end of physical
397 * memory from the boot time page table:
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
))
405 pud
= pud_offset(pgd
, va
);
406 pmd
= pmd_offset(pud
, va
);
407 if (!pmd_present(*pmd
))
410 pte
= pte_offset_kernel(pmd
, va
);
411 if (!pte_present(*pte
))
414 pte_clear(NULL
, va
, pte
);
416 paravirt_alloc_pmd(&init_mm
, __pa(base
) >> PAGE_SHIFT
);
419 void __init
native_pagetable_setup_done(pgd_t
*base
)
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
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.
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.
438 * In general, pagetable_init() assumes that the pagetable may already
439 * be partially populated, and so it avoids stomping on any existing
442 static void __init
early_ioremap_page_table_range_init(pgd_t
*pgd_base
)
444 unsigned long vaddr
, end
;
447 * Fixed mappings, only the page table structure has to be
448 * created - mappings will be set by set_fixmap():
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();
457 static void __init
pagetable_init(void)
459 pgd_t
*pgd_base
= swapper_pg_dir
;
461 paravirt_pagetable_setup_start(pgd_base
);
463 permanent_kmaps_init(pgd_base
);
465 paravirt_pagetable_setup_done(pgd_base
);
468 #ifdef CONFIG_ACPI_SLEEP
470 * ACPI suspend needs this for resume, because things like the intel-agp
471 * driver might have split up a kernel 4MB mapping.
473 char swsusp_pg_dir
[PAGE_SIZE
]
474 __attribute__ ((aligned(PAGE_SIZE
)));
476 static inline void save_pg_dir(void)
478 memcpy(swsusp_pg_dir
, swapper_pg_dir
, PAGE_SIZE
);
480 #else /* !CONFIG_ACPI_SLEEP */
481 static inline void save_pg_dir(void)
484 #endif /* !CONFIG_ACPI_SLEEP */
486 void zap_low_mappings(void)
491 * Zap initial low-memory mappings.
493 * Note that "pgd_clear()" doesn't do it for
494 * us, because pgd_clear() is a no-op on i386.
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
)));
500 set_pgd(swapper_pg_dir
+i
, __pgd(0));
508 pteval_t __supported_pte_mask __read_mostly
= ~(_PAGE_NX
| _PAGE_GLOBAL
);
509 EXPORT_SYMBOL_GPL(__supported_pte_mask
);
511 #ifdef CONFIG_X86_PAE
513 static int disable_nx __initdata
;
518 * Control non executable mappings.
523 static int __init
noexec_setup(char *str
)
525 if (!str
|| !strcmp(str
, "on")) {
527 __supported_pte_mask
|= _PAGE_NX
;
531 if (!strcmp(str
, "off")) {
533 __supported_pte_mask
&= ~_PAGE_NX
;
541 early_param("noexec", noexec_setup
);
543 static void __init
set_nx(void)
545 unsigned int v
[4], l
, h
;
547 if (cpu_has_pae
&& (cpuid_eax(0x80000000) > 0x80000001)) {
548 cpuid(0x80000001, &v
[0], &v
[1], &v
[2], &v
[3]);
550 if ((v
[3] & (1 << 20)) && !disable_nx
) {
551 rdmsr(MSR_EFER
, l
, h
);
553 wrmsr(MSR_EFER
, l
, h
);
555 __supported_pte_mask
|= _PAGE_NX
;
561 /* user-defined highmem size */
562 static unsigned int highmem_pages
= -1;
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.
569 static int __init
parse_highmem(char *arg
)
574 highmem_pages
= memparse(arg
, &arg
) >> PAGE_SHIFT
;
577 early_param("highmem", parse_highmem
);
580 * Determine low and high memory ranges:
582 void __init
find_low_pfn_range(void)
584 /* it could update max_pfn */
586 /* max_low_pfn is 0, we already have early_res support */
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
));
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",
606 if (max_pfn
> MAX_NONPAE_PFN
)
608 "Use a HIGHMEM64G enabled kernel.\n");
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");
619 #endif /* !CONFIG_HIGHMEM64G */
620 #endif /* !CONFIG_HIGHMEM */
622 if (highmem_pages
== -1)
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
));
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
));
640 max_low_pfn
-= highmem_pages
;
644 printk(KERN_ERR
"ignoring highmem size on non-highmem"
650 #ifndef CONFIG_NEED_MULTIPLE_NODES
651 void __init
initmem_init(unsigned long start_pfn
,
652 unsigned long end_pfn
)
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;
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;
670 #ifdef CONFIG_FLATMEM
671 max_mapnr
= num_physpages
;
673 printk(KERN_NOTICE
"%ldMB LOWMEM available.\n",
674 pages_to_mb(max_low_pfn
));
676 setup_bootmem_allocator();
678 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
680 static void __init
zone_sizes_init(void)
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
;
691 free_area_init_nodes(max_zone_pfns
);
694 void __init
setup_bootmem_allocator(void)
697 unsigned long bootmap_size
, bootmap
;
699 * Initialize the boot-time allocator (with low memory only):
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
,
706 panic("Cannot find bootmem map of size %ld\n", bootmap_size
);
707 reserve_early(bootmap
, bootmap
+ bootmap_size
, "BOOTMAP");
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
);
722 after_init_bootmem
= 1;
725 static void __init
find_early_table_space(unsigned long end
)
727 unsigned long puds
, pmds
, ptes
, tables
, start
;
729 puds
= (end
+ PUD_SIZE
- 1) >> PUD_SHIFT
;
730 tables
= PAGE_ALIGN(puds
* sizeof(pud_t
));
732 pmds
= (end
+ PMD_SIZE
- 1) >> PMD_SHIFT
;
733 tables
+= PAGE_ALIGN(pmds
* sizeof(pmd_t
));
738 extra
= end
- ((end
>>PMD_SHIFT
) << PMD_SHIFT
);
740 ptes
= (extra
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
742 ptes
= (end
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
744 tables
+= PAGE_ALIGN(ptes
* sizeof(pte_t
));
747 tables
+= PAGE_SIZE
* 2;
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.
755 table_start
= find_e820_area(start
, max_pfn_mapped
<<PAGE_SHIFT
,
757 if (table_start
== -1UL)
758 panic("Cannot find space for the kernel page tables");
760 table_start
>>= PAGE_SHIFT
;
761 table_end
= table_start
;
762 table_top
= table_start
+ (tables
>>PAGE_SHIFT
);
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
);
769 unsigned long __init_refok
init_memory_mapping(unsigned long start
,
772 pgd_t
*pgd_base
= swapper_pg_dir
;
773 unsigned long start_pfn
, end_pfn
;
774 unsigned long big_page_start
;
777 * Find space for the kernel direct mapping tables.
779 if (!after_init_bootmem
)
780 find_early_table_space(end
);
782 #ifdef CONFIG_X86_PAE
785 printk(KERN_INFO
"NX (Execute Disable) protection: active\n");
788 /* Enable PSE if available */
790 set_in_cr4(X86_CR4_PSE
);
792 /* Enable PGE if available */
794 set_in_cr4(X86_CR4_PGE
);
795 __supported_pte_mask
|= _PAGE_GLOBAL
;
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
804 big_page_start
= PMD_SIZE
;
806 if (start
< big_page_start
) {
807 start_pfn
= start
>> PAGE_SHIFT
;
808 end_pfn
= min(big_page_start
>>PAGE_SHIFT
, end
>>PAGE_SHIFT
);
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
);
815 if (start_pfn
< end_pfn
)
816 kernel_physical_mapping_init(pgd_base
, start_pfn
, end_pfn
, 0);
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
,
828 /* tail is not big page alignment ? */
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
,
837 early_ioremap_page_table_range_init(pgd_base
);
839 load_cr3(swapper_pg_dir
);
843 if (!after_init_bootmem
)
844 reserve_early(table_start
<< PAGE_SHIFT
,
845 table_end
<< PAGE_SHIFT
, "PGTABLE");
847 return end
>> PAGE_SHIFT
;
852 * paging_init() sets up the page tables - note that the first 8MB are
853 * already mapped by head.S.
855 * This routines also unmaps the page at virtual kernel address 0, so
856 * that we can trap those pesky NULL-reference errors in the kernel.
858 void __init
paging_init(void)
867 * NOTE: at this point the bootmem allocator is fully available.
872 paravirt_post_allocator_init();
876 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
877 * and also on some strange 486's. All 586+'s are OK. This used to involve
878 * black magic jumps to work around some nasty CPU bugs, but fortunately the
879 * switch to using exceptions got rid of all that.
881 static void __init
test_wp_bit(void)
884 "Checking if this processor honours the WP bit even in supervisor mode...");
886 /* Any page-aligned address will do, the test is non-destructive */
887 __set_fixmap(FIX_WP_TEST
, __pa(&swapper_pg_dir
), PAGE_READONLY
);
888 boot_cpu_data
.wp_works_ok
= do_test_wp_bit();
889 clear_fixmap(FIX_WP_TEST
);
891 if (!boot_cpu_data
.wp_works_ok
) {
892 printk(KERN_CONT
"No.\n");
893 #ifdef CONFIG_X86_WP_WORKS_OK
895 "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
898 printk(KERN_CONT
"Ok.\n");
902 static struct kcore_list kcore_mem
, kcore_vmalloc
;
904 void __init
mem_init(void)
906 int codesize
, reservedpages
, datasize
, initsize
;
909 #ifdef CONFIG_FLATMEM
912 /* this will put all low memory onto the freelists */
913 totalram_pages
+= free_all_bootmem();
916 for (tmp
= 0; tmp
< max_low_pfn
; tmp
++)
918 * Only count reserved RAM pages:
920 if (page_is_ram(tmp
) && PageReserved(pfn_to_page(tmp
)))
923 set_highmem_pages_init();
925 codesize
= (unsigned long) &_etext
- (unsigned long) &_text
;
926 datasize
= (unsigned long) &_edata
- (unsigned long) &_etext
;
927 initsize
= (unsigned long) &__init_end
- (unsigned long) &__init_begin
;
929 kclist_add(&kcore_mem
, __va(0), max_low_pfn
<< PAGE_SHIFT
);
930 kclist_add(&kcore_vmalloc
, (void *)VMALLOC_START
,
931 VMALLOC_END
-VMALLOC_START
);
933 printk(KERN_INFO
"Memory: %luk/%luk available (%dk kernel code, "
934 "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
935 (unsigned long) nr_free_pages() << (PAGE_SHIFT
-10),
936 num_physpages
<< (PAGE_SHIFT
-10),
938 reservedpages
<< (PAGE_SHIFT
-10),
941 (unsigned long) (totalhigh_pages
<< (PAGE_SHIFT
-10))
944 printk(KERN_INFO
"virtual kernel memory layout:\n"
945 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
946 #ifdef CONFIG_HIGHMEM
947 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
949 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
950 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
951 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
952 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
953 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
954 FIXADDR_START
, FIXADDR_TOP
,
955 (FIXADDR_TOP
- FIXADDR_START
) >> 10,
957 #ifdef CONFIG_HIGHMEM
958 PKMAP_BASE
, PKMAP_BASE
+LAST_PKMAP
*PAGE_SIZE
,
959 (LAST_PKMAP
*PAGE_SIZE
) >> 10,
962 VMALLOC_START
, VMALLOC_END
,
963 (VMALLOC_END
- VMALLOC_START
) >> 20,
965 (unsigned long)__va(0), (unsigned long)high_memory
,
966 ((unsigned long)high_memory
- (unsigned long)__va(0)) >> 20,
968 (unsigned long)&__init_begin
, (unsigned long)&__init_end
,
969 ((unsigned long)&__init_end
-
970 (unsigned long)&__init_begin
) >> 10,
972 (unsigned long)&_etext
, (unsigned long)&_edata
,
973 ((unsigned long)&_edata
- (unsigned long)&_etext
) >> 10,
975 (unsigned long)&_text
, (unsigned long)&_etext
,
976 ((unsigned long)&_etext
- (unsigned long)&_text
) >> 10);
978 #ifdef CONFIG_HIGHMEM
979 BUG_ON(PKMAP_BASE
+ LAST_PKMAP
*PAGE_SIZE
> FIXADDR_START
);
980 BUG_ON(VMALLOC_END
> PKMAP_BASE
);
982 BUG_ON(VMALLOC_START
> VMALLOC_END
);
983 BUG_ON((unsigned long)high_memory
> VMALLOC_START
);
985 if (boot_cpu_data
.wp_works_ok
< 0)
993 #ifdef CONFIG_MEMORY_HOTPLUG
994 int arch_add_memory(int nid
, u64 start
, u64 size
)
996 struct pglist_data
*pgdata
= NODE_DATA(nid
);
997 struct zone
*zone
= pgdata
->node_zones
+ ZONE_HIGHMEM
;
998 unsigned long start_pfn
= start
>> PAGE_SHIFT
;
999 unsigned long nr_pages
= size
>> PAGE_SHIFT
;
1001 return __add_pages(zone
, start_pfn
, nr_pages
);
1006 * This function cannot be __init, since exceptions don't work in that
1007 * section. Put this after the callers, so that it cannot be inlined.
1009 static noinline
int do_test_wp_bit(void)
1014 __asm__
__volatile__(
1020 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST
)),
1029 #ifdef CONFIG_DEBUG_RODATA
1030 const int rodata_test_data
= 0xC3;
1031 EXPORT_SYMBOL_GPL(rodata_test_data
);
1033 void mark_rodata_ro(void)
1035 unsigned long start
= PFN_ALIGN(_text
);
1036 unsigned long size
= PFN_ALIGN(_etext
) - start
;
1038 set_pages_ro(virt_to_page(start
), size
>> PAGE_SHIFT
);
1039 printk(KERN_INFO
"Write protecting the kernel text: %luk\n",
1042 #ifdef CONFIG_CPA_DEBUG
1043 printk(KERN_INFO
"Testing CPA: Reverting %lx-%lx\n",
1045 set_pages_rw(virt_to_page(start
), size
>>PAGE_SHIFT
);
1047 printk(KERN_INFO
"Testing CPA: write protecting again\n");
1048 set_pages_ro(virt_to_page(start
), size
>>PAGE_SHIFT
);
1051 size
= (unsigned long)__end_rodata
- start
;
1052 set_pages_ro(virt_to_page(start
), size
>> PAGE_SHIFT
);
1053 printk(KERN_INFO
"Write protecting the kernel read-only data: %luk\n",
1057 #ifdef CONFIG_CPA_DEBUG
1058 printk(KERN_INFO
"Testing CPA: undo %lx-%lx\n", start
, start
+ size
);
1059 set_pages_rw(virt_to_page(start
), size
>> PAGE_SHIFT
);
1061 printk(KERN_INFO
"Testing CPA: write protecting again\n");
1062 set_pages_ro(virt_to_page(start
), size
>> PAGE_SHIFT
);
1067 void free_init_pages(char *what
, unsigned long begin
, unsigned long end
)
1069 #ifdef CONFIG_DEBUG_PAGEALLOC
1071 * If debugging page accesses then do not free this memory but
1072 * mark them not present - any buggy init-section access will
1073 * create a kernel page fault:
1075 printk(KERN_INFO
"debug: unmapping init memory %08lx..%08lx\n",
1076 begin
, PAGE_ALIGN(end
));
1077 set_memory_np(begin
, (end
- begin
) >> PAGE_SHIFT
);
1082 * We just marked the kernel text read only above, now that
1083 * we are going to free part of that, we need to make that
1086 set_memory_rw(begin
, (end
- begin
) >> PAGE_SHIFT
);
1088 for (addr
= begin
; addr
< end
; addr
+= PAGE_SIZE
) {
1089 ClearPageReserved(virt_to_page(addr
));
1090 init_page_count(virt_to_page(addr
));
1091 memset((void *)addr
, POISON_FREE_INITMEM
, PAGE_SIZE
);
1095 printk(KERN_INFO
"Freeing %s: %luk freed\n", what
, (end
- begin
) >> 10);
1099 void free_initmem(void)
1101 free_init_pages("unused kernel memory",
1102 (unsigned long)(&__init_begin
),
1103 (unsigned long)(&__init_end
));
1106 #ifdef CONFIG_BLK_DEV_INITRD
1107 void free_initrd_mem(unsigned long start
, unsigned long end
)
1109 free_init_pages("initrd memory", start
, end
);
1113 int __init
reserve_bootmem_generic(unsigned long phys
, unsigned long len
,
1116 return reserve_bootmem(phys
, len
, flags
);