2 * linux/arch/i386/mm/init.c
4 * Copyright (C) 1995 Linus Torvalds
6 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
9 #include <linux/config.h>
10 #include <linux/module.h>
11 #include <linux/signal.h>
12 #include <linux/sched.h>
13 #include <linux/kernel.h>
14 #include <linux/errno.h>
15 #include <linux/string.h>
16 #include <linux/types.h>
17 #include <linux/ptrace.h>
18 #include <linux/mman.h>
20 #include <linux/hugetlb.h>
21 #include <linux/swap.h>
22 #include <linux/smp.h>
23 #include <linux/init.h>
24 #include <linux/highmem.h>
25 #include <linux/pagemap.h>
26 #include <linux/bootmem.h>
27 #include <linux/slab.h>
28 #include <linux/proc_fs.h>
29 #include <linux/efi.h>
31 #include <asm/processor.h>
32 #include <asm/system.h>
33 #include <asm/uaccess.h>
34 #include <asm/pgtable.h>
36 #include <asm/fixmap.h>
40 #include <asm/tlbflush.h>
41 #include <asm/sections.h>
43 unsigned int __VMALLOC_RESERVE
= 128 << 20;
45 DEFINE_PER_CPU(struct mmu_gather
, mmu_gathers
);
46 unsigned long highstart_pfn
, highend_pfn
;
48 static int noinline
do_test_wp_bit(void);
51 * Creates a middle page table and puts a pointer to it in the
52 * given global directory entry. This only returns the gd entry
53 * in non-PAE compilation mode, since the middle layer is folded.
55 static pmd_t
* __init
one_md_table_init(pgd_t
*pgd
)
61 pmd_table
= (pmd_t
*) alloc_bootmem_low_pages(PAGE_SIZE
);
62 set_pgd(pgd
, __pgd(__pa(pmd_table
) | _PAGE_PRESENT
));
63 pud
= pud_offset(pgd
, 0);
64 if (pmd_table
!= pmd_offset(pud
, 0))
67 pud
= pud_offset(pgd
, 0);
68 pmd_table
= pmd_offset(pud
, 0);
75 * Create a page table and place a pointer to it in a middle page
78 static pte_t
* __init
one_page_table_init(pmd_t
*pmd
)
81 pte_t
*page_table
= (pte_t
*) alloc_bootmem_low_pages(PAGE_SIZE
);
82 set_pmd(pmd
, __pmd(__pa(page_table
) | _PAGE_TABLE
));
83 if (page_table
!= pte_offset_kernel(pmd
, 0))
89 return pte_offset_kernel(pmd
, 0);
93 * This function initializes a certain range of kernel virtual memory
94 * with new bootmem page tables, everywhere page tables are missing in
99 * NOTE: The pagetables are allocated contiguous on the physical space
100 * so we can cache the place of the first one and move around without
101 * checking the pgd every time.
103 static void __init
page_table_range_init (unsigned long start
, unsigned long end
, pgd_t
*pgd_base
)
108 int pgd_idx
, pmd_idx
;
112 pgd_idx
= pgd_index(vaddr
);
113 pmd_idx
= pmd_index(vaddr
);
114 pgd
= pgd_base
+ pgd_idx
;
116 for ( ; (pgd_idx
< PTRS_PER_PGD
) && (vaddr
!= end
); pgd
++, pgd_idx
++) {
118 one_md_table_init(pgd
);
119 pud
= pud_offset(pgd
, vaddr
);
120 pmd
= pmd_offset(pud
, vaddr
);
121 for (; (pmd_idx
< PTRS_PER_PMD
) && (vaddr
!= end
); pmd
++, pmd_idx
++) {
123 one_page_table_init(pmd
);
131 static inline int is_kernel_text(unsigned long addr
)
133 if (addr
>= PAGE_OFFSET
&& addr
<= (unsigned long)__init_end
)
139 * This maps the physical memory to kernel virtual address space, a total
140 * of max_low_pfn pages, by creating page tables starting from address
143 static void __init
kernel_physical_mapping_init(pgd_t
*pgd_base
)
149 int pgd_idx
, pmd_idx
, pte_ofs
;
151 pgd_idx
= pgd_index(PAGE_OFFSET
);
152 pgd
= pgd_base
+ pgd_idx
;
155 for (; pgd_idx
< PTRS_PER_PGD
; pgd
++, pgd_idx
++) {
156 pmd
= one_md_table_init(pgd
);
157 if (pfn
>= max_low_pfn
)
159 for (pmd_idx
= 0; pmd_idx
< PTRS_PER_PMD
&& pfn
< max_low_pfn
; pmd
++, pmd_idx
++) {
160 unsigned int address
= pfn
* PAGE_SIZE
+ PAGE_OFFSET
;
162 /* Map with big pages if possible, otherwise create normal page tables. */
164 unsigned int address2
= (pfn
+ PTRS_PER_PTE
- 1) * PAGE_SIZE
+ PAGE_OFFSET
+ PAGE_SIZE
-1;
166 if (is_kernel_text(address
) || is_kernel_text(address2
))
167 set_pmd(pmd
, pfn_pmd(pfn
, PAGE_KERNEL_LARGE_EXEC
));
169 set_pmd(pmd
, pfn_pmd(pfn
, PAGE_KERNEL_LARGE
));
172 pte
= one_page_table_init(pmd
);
174 for (pte_ofs
= 0; pte_ofs
< PTRS_PER_PTE
&& pfn
< max_low_pfn
; pte
++, pfn
++, pte_ofs
++) {
175 if (is_kernel_text(address
))
176 set_pte(pte
, pfn_pte(pfn
, PAGE_KERNEL_EXEC
));
178 set_pte(pte
, pfn_pte(pfn
, PAGE_KERNEL
));
185 static inline int page_kills_ppro(unsigned long pagenr
)
187 if (pagenr
>= 0x70000 && pagenr
<= 0x7003F)
192 extern int is_available_memory(efi_memory_desc_t
*);
194 int page_is_ram(unsigned long pagenr
)
197 unsigned long addr
, end
;
200 efi_memory_desc_t
*md
;
202 for (i
= 0; i
< memmap
.nr_map
; i
++) {
204 if (!is_available_memory(md
))
206 addr
= (md
->phys_addr
+PAGE_SIZE
-1) >> PAGE_SHIFT
;
207 end
= (md
->phys_addr
+ (md
->num_pages
<< EFI_PAGE_SHIFT
)) >> PAGE_SHIFT
;
209 if ((pagenr
>= addr
) && (pagenr
< end
))
215 for (i
= 0; i
< e820
.nr_map
; i
++) {
217 if (e820
.map
[i
].type
!= E820_RAM
) /* not usable memory */
220 * !!!FIXME!!! Some BIOSen report areas as RAM that
221 * are not. Notably the 640->1Mb area. We need a sanity
224 addr
= (e820
.map
[i
].addr
+PAGE_SIZE
-1) >> PAGE_SHIFT
;
225 end
= (e820
.map
[i
].addr
+e820
.map
[i
].size
) >> PAGE_SHIFT
;
226 if ((pagenr
>= addr
) && (pagenr
< end
))
232 #ifdef CONFIG_HIGHMEM
236 #define kmap_get_fixmap_pte(vaddr) \
237 pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), vaddr), (vaddr)), (vaddr))
239 static void __init
kmap_init(void)
241 unsigned long kmap_vstart
;
243 /* cache the first kmap pte */
244 kmap_vstart
= __fix_to_virt(FIX_KMAP_BEGIN
);
245 kmap_pte
= kmap_get_fixmap_pte(kmap_vstart
);
247 kmap_prot
= PAGE_KERNEL
;
250 static void __init
permanent_kmaps_init(pgd_t
*pgd_base
)
259 page_table_range_init(vaddr
, vaddr
+ PAGE_SIZE
*LAST_PKMAP
, pgd_base
);
261 pgd
= swapper_pg_dir
+ pgd_index(vaddr
);
262 pud
= pud_offset(pgd
, vaddr
);
263 pmd
= pmd_offset(pud
, vaddr
);
264 pte
= pte_offset_kernel(pmd
, vaddr
);
265 pkmap_page_table
= pte
;
268 void __init
one_highpage_init(struct page
*page
, int pfn
, int bad_ppro
)
270 if (page_is_ram(pfn
) && !(bad_ppro
&& page_kills_ppro(pfn
))) {
271 ClearPageReserved(page
);
272 set_page_count(page
, 1);
276 SetPageReserved(page
);
280 extern void set_highmem_pages_init(int);
282 static void __init
set_highmem_pages_init(int bad_ppro
)
285 for (pfn
= highstart_pfn
; pfn
< highend_pfn
; pfn
++)
286 one_highpage_init(pfn_to_page(pfn
), pfn
, bad_ppro
);
287 totalram_pages
+= totalhigh_pages
;
289 #endif /* CONFIG_FLATMEM */
292 #define kmap_init() do { } while (0)
293 #define permanent_kmaps_init(pgd_base) do { } while (0)
294 #define set_highmem_pages_init(bad_ppro) do { } while (0)
295 #endif /* CONFIG_HIGHMEM */
297 unsigned long long __PAGE_KERNEL
= _PAGE_KERNEL
;
298 unsigned long long __PAGE_KERNEL_EXEC
= _PAGE_KERNEL_EXEC
;
301 extern void __init
remap_numa_kva(void);
303 #define remap_numa_kva() do {} while (0)
306 static void __init
pagetable_init (void)
309 pgd_t
*pgd_base
= swapper_pg_dir
;
311 #ifdef CONFIG_X86_PAE
313 /* Init entries of the first-level page table to the zero page */
314 for (i
= 0; i
< PTRS_PER_PGD
; i
++)
315 set_pgd(pgd_base
+ i
, __pgd(__pa(empty_zero_page
) | _PAGE_PRESENT
));
318 /* Enable PSE if available */
320 set_in_cr4(X86_CR4_PSE
);
323 /* Enable PGE if available */
325 set_in_cr4(X86_CR4_PGE
);
326 __PAGE_KERNEL
|= _PAGE_GLOBAL
;
327 __PAGE_KERNEL_EXEC
|= _PAGE_GLOBAL
;
330 kernel_physical_mapping_init(pgd_base
);
334 * Fixed mappings, only the page table structure has to be
335 * created - mappings will be set by set_fixmap():
337 vaddr
= __fix_to_virt(__end_of_fixed_addresses
- 1) & PMD_MASK
;
338 page_table_range_init(vaddr
, 0, pgd_base
);
340 permanent_kmaps_init(pgd_base
);
342 #ifdef CONFIG_X86_PAE
344 * Add low memory identity-mappings - SMP needs it when
345 * starting up on an AP from real-mode. In the non-PAE
346 * case we already have these mappings through head.S.
347 * All user-space mappings are explicitly cleared after
350 pgd_base
[0] = pgd_base
[USER_PTRS_PER_PGD
];
354 #if defined(CONFIG_PM_DISK) || defined(CONFIG_SOFTWARE_SUSPEND)
356 * Swap suspend & friends need this for resume because things like the intel-agp
357 * driver might have split up a kernel 4MB mapping.
359 char __nosavedata swsusp_pg_dir
[PAGE_SIZE
]
360 __attribute__ ((aligned (PAGE_SIZE
)));
362 static inline void save_pg_dir(void)
364 memcpy(swsusp_pg_dir
, swapper_pg_dir
, PAGE_SIZE
);
367 static inline void save_pg_dir(void)
372 void zap_low_mappings (void)
379 * Zap initial low-memory mappings.
381 * Note that "pgd_clear()" doesn't do it for
382 * us, because pgd_clear() is a no-op on i386.
384 for (i
= 0; i
< USER_PTRS_PER_PGD
; i
++)
385 #ifdef CONFIG_X86_PAE
386 set_pgd(swapper_pg_dir
+i
, __pgd(1 + __pa(empty_zero_page
)));
388 set_pgd(swapper_pg_dir
+i
, __pgd(0));
393 static int disable_nx __initdata
= 0;
394 u64 __supported_pte_mask
= ~_PAGE_NX
;
399 * Control non executable mappings.
404 void __init
noexec_setup(const char *str
)
406 if (!strncmp(str
, "on",2) && cpu_has_nx
) {
407 __supported_pte_mask
|= _PAGE_NX
;
409 } else if (!strncmp(str
,"off",3)) {
411 __supported_pte_mask
&= ~_PAGE_NX
;
416 #ifdef CONFIG_X86_PAE
418 static void __init
set_nx(void)
420 unsigned int v
[4], l
, h
;
422 if (cpu_has_pae
&& (cpuid_eax(0x80000000) > 0x80000001)) {
423 cpuid(0x80000001, &v
[0], &v
[1], &v
[2], &v
[3]);
424 if ((v
[3] & (1 << 20)) && !disable_nx
) {
425 rdmsr(MSR_EFER
, l
, h
);
427 wrmsr(MSR_EFER
, l
, h
);
429 __supported_pte_mask
|= _PAGE_NX
;
435 * Enables/disables executability of a given kernel page and
436 * returns the previous setting.
438 int __init
set_kernel_exec(unsigned long vaddr
, int enable
)
446 pte
= lookup_address(vaddr
);
449 if (!pte_exec_kernel(*pte
))
453 pte
->pte_high
&= ~(1 << (_PAGE_BIT_NX
- 32));
455 pte
->pte_high
|= 1 << (_PAGE_BIT_NX
- 32);
464 * paging_init() sets up the page tables - note that the first 8MB are
465 * already mapped by head.S.
467 * This routines also unmaps the page at virtual kernel address 0, so
468 * that we can trap those pesky NULL-reference errors in the kernel.
470 void __init
paging_init(void)
472 #ifdef CONFIG_X86_PAE
475 printk("NX (Execute Disable) protection: active\n");
480 load_cr3(swapper_pg_dir
);
482 #ifdef CONFIG_X86_PAE
484 * We will bail out later - printk doesn't work right now so
485 * the user would just see a hanging kernel.
488 set_in_cr4(X86_CR4_PAE
);
496 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
497 * and also on some strange 486's (NexGen etc.). All 586+'s are OK. This
498 * used to involve black magic jumps to work around some nasty CPU bugs,
499 * but fortunately the switch to using exceptions got rid of all that.
502 static void __init
test_wp_bit(void)
504 printk("Checking if this processor honours the WP bit even in supervisor mode... ");
506 /* Any page-aligned address will do, the test is non-destructive */
507 __set_fixmap(FIX_WP_TEST
, __pa(&swapper_pg_dir
), PAGE_READONLY
);
508 boot_cpu_data
.wp_works_ok
= do_test_wp_bit();
509 clear_fixmap(FIX_WP_TEST
);
511 if (!boot_cpu_data
.wp_works_ok
) {
513 #ifdef CONFIG_X86_WP_WORKS_OK
514 panic("This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
521 static void __init
set_max_mapnr_init(void)
523 #ifdef CONFIG_HIGHMEM
524 num_physpages
= highend_pfn
;
526 num_physpages
= max_low_pfn
;
528 #ifdef CONFIG_FLATMEM
529 max_mapnr
= num_physpages
;
533 static struct kcore_list kcore_mem
, kcore_vmalloc
;
535 void __init
mem_init(void)
537 extern int ppro_with_ram_bug(void);
538 int codesize
, reservedpages
, datasize
, initsize
;
542 #ifdef CONFIG_FLATMEM
547 bad_ppro
= ppro_with_ram_bug();
549 #ifdef CONFIG_HIGHMEM
550 /* check that fixmap and pkmap do not overlap */
551 if (PKMAP_BASE
+LAST_PKMAP
*PAGE_SIZE
>= FIXADDR_START
) {
552 printk(KERN_ERR
"fixmap and kmap areas overlap - this will crash\n");
553 printk(KERN_ERR
"pkstart: %lxh pkend: %lxh fixstart %lxh\n",
554 PKMAP_BASE
, PKMAP_BASE
+LAST_PKMAP
*PAGE_SIZE
, FIXADDR_START
);
559 set_max_mapnr_init();
561 #ifdef CONFIG_HIGHMEM
562 high_memory
= (void *) __va(highstart_pfn
* PAGE_SIZE
- 1) + 1;
564 high_memory
= (void *) __va(max_low_pfn
* PAGE_SIZE
- 1) + 1;
567 /* this will put all low memory onto the freelists */
568 totalram_pages
+= free_all_bootmem();
571 for (tmp
= 0; tmp
< max_low_pfn
; tmp
++)
573 * Only count reserved RAM pages
575 if (page_is_ram(tmp
) && PageReserved(pfn_to_page(tmp
)))
578 set_highmem_pages_init(bad_ppro
);
580 codesize
= (unsigned long) &_etext
- (unsigned long) &_text
;
581 datasize
= (unsigned long) &_edata
- (unsigned long) &_etext
;
582 initsize
= (unsigned long) &__init_end
- (unsigned long) &__init_begin
;
584 kclist_add(&kcore_mem
, __va(0), max_low_pfn
<< PAGE_SHIFT
);
585 kclist_add(&kcore_vmalloc
, (void *)VMALLOC_START
,
586 VMALLOC_END
-VMALLOC_START
);
588 printk(KERN_INFO
"Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
589 (unsigned long) nr_free_pages() << (PAGE_SHIFT
-10),
590 num_physpages
<< (PAGE_SHIFT
-10),
592 reservedpages
<< (PAGE_SHIFT
-10),
595 (unsigned long) (totalhigh_pages
<< (PAGE_SHIFT
-10))
598 #ifdef CONFIG_X86_PAE
600 panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");
602 if (boot_cpu_data
.wp_works_ok
< 0)
606 * Subtle. SMP is doing it's boot stuff late (because it has to
607 * fork idle threads) - but it also needs low mappings for the
608 * protected-mode entry to work. We zap these entries only after
609 * the WP-bit has been tested.
616 kmem_cache_t
*pgd_cache
;
617 kmem_cache_t
*pmd_cache
;
619 void __init
pgtable_cache_init(void)
621 if (PTRS_PER_PMD
> 1) {
622 pmd_cache
= kmem_cache_create("pmd",
623 PTRS_PER_PMD
*sizeof(pmd_t
),
624 PTRS_PER_PMD
*sizeof(pmd_t
),
629 panic("pgtable_cache_init(): cannot create pmd cache");
631 pgd_cache
= kmem_cache_create("pgd",
632 PTRS_PER_PGD
*sizeof(pgd_t
),
633 PTRS_PER_PGD
*sizeof(pgd_t
),
636 PTRS_PER_PMD
== 1 ? pgd_dtor
: NULL
);
638 panic("pgtable_cache_init(): Cannot create pgd cache");
642 * This function cannot be __init, since exceptions don't work in that
643 * section. Put this after the callers, so that it cannot be inlined.
645 static int noinline
do_test_wp_bit(void)
650 __asm__
__volatile__(
655 ".section __ex_table,\"a\"\n"
659 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST
)),
668 void free_initmem(void)
672 addr
= (unsigned long)(&__init_begin
);
673 for (; addr
< (unsigned long)(&__init_end
); addr
+= PAGE_SIZE
) {
674 ClearPageReserved(virt_to_page(addr
));
675 set_page_count(virt_to_page(addr
), 1);
676 memset((void *)addr
, 0xcc, PAGE_SIZE
);
680 printk (KERN_INFO
"Freeing unused kernel memory: %dk freed\n", (__init_end
- __init_begin
) >> 10);
683 #ifdef CONFIG_BLK_DEV_INITRD
684 void free_initrd_mem(unsigned long start
, unsigned long end
)
687 printk (KERN_INFO
"Freeing initrd memory: %ldk freed\n", (end
- start
) >> 10);
688 for (; start
< end
; start
+= PAGE_SIZE
) {
689 ClearPageReserved(virt_to_page(start
));
690 set_page_count(virt_to_page(start
), 1);