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_pfn_mapped
;
55 DEFINE_PER_CPU(struct mmu_gather
, mmu_gathers
);
56 unsigned long highstart_pfn
, highend_pfn
;
58 static noinline
int do_test_wp_bit(void);
61 * Creates a middle page table and puts a pointer to it in the
62 * given global directory entry. This only returns the gd entry
63 * in non-PAE compilation mode, since the middle layer is folded.
65 static pmd_t
* __init
one_md_table_init(pgd_t
*pgd
)
71 if (!(pgd_val(*pgd
) & _PAGE_PRESENT
)) {
72 pmd_table
= (pmd_t
*) alloc_bootmem_low_pages(PAGE_SIZE
);
74 paravirt_alloc_pmd(&init_mm
, __pa(pmd_table
) >> PAGE_SHIFT
);
75 set_pgd(pgd
, __pgd(__pa(pmd_table
) | _PAGE_PRESENT
));
76 pud
= pud_offset(pgd
, 0);
77 BUG_ON(pmd_table
!= pmd_offset(pud
, 0));
80 pud
= pud_offset(pgd
, 0);
81 pmd_table
= pmd_offset(pud
, 0);
87 * Create a page table and place a pointer to it in a middle page
90 static pte_t
* __init
one_page_table_init(pmd_t
*pmd
)
92 if (!(pmd_val(*pmd
) & _PAGE_PRESENT
)) {
93 pte_t
*page_table
= NULL
;
95 #ifdef CONFIG_DEBUG_PAGEALLOC
96 page_table
= (pte_t
*) alloc_bootmem_pages(PAGE_SIZE
);
100 (pte_t
*)alloc_bootmem_low_pages(PAGE_SIZE
);
103 paravirt_alloc_pte(&init_mm
, __pa(page_table
) >> PAGE_SHIFT
);
104 set_pmd(pmd
, __pmd(__pa(page_table
) | _PAGE_TABLE
));
105 BUG_ON(page_table
!= pte_offset_kernel(pmd
, 0));
108 return pte_offset_kernel(pmd
, 0);
112 * This function initializes a certain range of kernel virtual memory
113 * with new bootmem page tables, everywhere page tables are missing in
116 * NOTE: The pagetables are allocated contiguous on the physical space
117 * so we can cache the place of the first one and move around without
118 * checking the pgd every time.
121 page_table_range_init(unsigned long start
, unsigned long end
, pgd_t
*pgd_base
)
123 int pgd_idx
, pmd_idx
;
129 pgd_idx
= pgd_index(vaddr
);
130 pmd_idx
= pmd_index(vaddr
);
131 pgd
= pgd_base
+ pgd_idx
;
133 for ( ; (pgd_idx
< PTRS_PER_PGD
) && (vaddr
!= end
); pgd
++, pgd_idx
++) {
134 pmd
= one_md_table_init(pgd
);
135 pmd
= pmd
+ pmd_index(vaddr
);
136 for (; (pmd_idx
< PTRS_PER_PMD
) && (vaddr
!= end
);
138 one_page_table_init(pmd
);
146 static inline int is_kernel_text(unsigned long addr
)
148 if (addr
>= PAGE_OFFSET
&& addr
<= (unsigned long)__init_end
)
154 * This maps the physical memory to kernel virtual address space, a total
155 * of max_low_pfn pages, by creating page tables starting from address
158 static void __init
kernel_physical_mapping_init(pgd_t
*pgd_base
)
160 int pgd_idx
, pmd_idx
, pte_ofs
;
166 pgd_idx
= pgd_index(PAGE_OFFSET
);
167 pgd
= pgd_base
+ pgd_idx
;
170 for (; pgd_idx
< PTRS_PER_PGD
; pgd
++, pgd_idx
++) {
171 pmd
= one_md_table_init(pgd
);
172 if (pfn
>= max_low_pfn
)
176 pmd_idx
< PTRS_PER_PMD
&& pfn
< max_low_pfn
;
178 unsigned int addr
= pfn
* PAGE_SIZE
+ PAGE_OFFSET
;
181 * Map with big pages if possible, otherwise
182 * create normal page tables:
184 * Don't use a large page for the first 2/4MB of memory
185 * because there are often fixed size MTRRs in there
186 * and overlapping MTRRs into large pages can cause
189 if (cpu_has_pse
&& !(pgd_idx
== 0 && pmd_idx
== 0)) {
191 pgprot_t prot
= PAGE_KERNEL_LARGE
;
193 addr2
= (pfn
+ PTRS_PER_PTE
-1) * PAGE_SIZE
+
194 PAGE_OFFSET
+ PAGE_SIZE
-1;
196 if (is_kernel_text(addr
) ||
197 is_kernel_text(addr2
))
198 prot
= PAGE_KERNEL_LARGE_EXEC
;
200 set_pmd(pmd
, pfn_pmd(pfn
, prot
));
203 max_pfn_mapped
= pfn
;
206 pte
= one_page_table_init(pmd
);
209 pte_ofs
< PTRS_PER_PTE
&& pfn
< max_low_pfn
;
210 pte
++, pfn
++, pte_ofs
++, addr
+= PAGE_SIZE
) {
211 pgprot_t prot
= PAGE_KERNEL
;
213 if (is_kernel_text(addr
))
214 prot
= PAGE_KERNEL_EXEC
;
216 set_pte(pte
, pfn_pte(pfn
, prot
));
218 max_pfn_mapped
= pfn
;
223 static inline int page_kills_ppro(unsigned long pagenr
)
225 if (pagenr
>= 0x70000 && pagenr
<= 0x7003F)
231 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
232 * is valid. The argument is a physical page number.
235 * On x86, access has to be given to the first megabyte of ram because that area
236 * contains bios code and data regions used by X and dosemu and similar apps.
237 * Access has to be given to non-kernel-ram areas as well, these contain the PCI
238 * mmio resources as well as potential bios/acpi data regions.
240 int devmem_is_allowed(unsigned long pagenr
)
244 if (!page_is_ram(pagenr
))
249 #ifdef CONFIG_HIGHMEM
253 static inline pte_t
*kmap_get_fixmap_pte(unsigned long vaddr
)
255 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr
),
256 vaddr
), vaddr
), vaddr
);
259 static void __init
kmap_init(void)
261 unsigned long kmap_vstart
;
264 * Cache the first kmap pte:
266 kmap_vstart
= __fix_to_virt(FIX_KMAP_BEGIN
);
267 kmap_pte
= kmap_get_fixmap_pte(kmap_vstart
);
269 kmap_prot
= PAGE_KERNEL
;
272 static void __init
permanent_kmaps_init(pgd_t
*pgd_base
)
281 page_table_range_init(vaddr
, vaddr
+ PAGE_SIZE
*LAST_PKMAP
, pgd_base
);
283 pgd
= swapper_pg_dir
+ pgd_index(vaddr
);
284 pud
= pud_offset(pgd
, vaddr
);
285 pmd
= pmd_offset(pud
, vaddr
);
286 pte
= pte_offset_kernel(pmd
, vaddr
);
287 pkmap_page_table
= pte
;
291 add_one_highpage_init(struct page
*page
, int pfn
, int bad_ppro
)
293 if (!(bad_ppro
&& page_kills_ppro(pfn
))) {
294 ClearPageReserved(page
);
295 init_page_count(page
);
299 SetPageReserved(page
);
302 struct add_highpages_data
{
303 unsigned long start_pfn
;
304 unsigned long end_pfn
;
308 static void __init
add_highpages_work_fn(unsigned long start_pfn
,
309 unsigned long end_pfn
, void *datax
)
313 unsigned long final_start_pfn
, final_end_pfn
;
314 struct add_highpages_data
*data
;
317 data
= (struct add_highpages_data
*)datax
;
318 bad_ppro
= data
->bad_ppro
;
320 final_start_pfn
= max(start_pfn
, data
->start_pfn
);
321 final_end_pfn
= min(end_pfn
, data
->end_pfn
);
322 if (final_start_pfn
>= final_end_pfn
)
325 for (node_pfn
= final_start_pfn
; node_pfn
< final_end_pfn
;
327 if (!pfn_valid(node_pfn
))
329 page
= pfn_to_page(node_pfn
);
330 add_one_highpage_init(page
, node_pfn
, bad_ppro
);
335 void __init
add_highpages_with_active_regions(int nid
, unsigned long start_pfn
,
336 unsigned long end_pfn
,
339 struct add_highpages_data data
;
341 data
.start_pfn
= start_pfn
;
342 data
.end_pfn
= end_pfn
;
343 data
.bad_ppro
= bad_ppro
;
345 work_with_active_regions(nid
, add_highpages_work_fn
, &data
);
349 static void __init
set_highmem_pages_init(int bad_ppro
)
351 add_highpages_with_active_regions(0, highstart_pfn
, highend_pfn
,
354 totalram_pages
+= totalhigh_pages
;
356 #endif /* !CONFIG_NUMA */
359 # define kmap_init() do { } while (0)
360 # define permanent_kmaps_init(pgd_base) do { } while (0)
361 # define set_highmem_pages_init(bad_ppro) do { } while (0)
362 #endif /* CONFIG_HIGHMEM */
364 pteval_t __PAGE_KERNEL
= _PAGE_KERNEL
;
365 EXPORT_SYMBOL(__PAGE_KERNEL
);
367 pteval_t __PAGE_KERNEL_EXEC
= _PAGE_KERNEL_EXEC
;
369 void __init
native_pagetable_setup_start(pgd_t
*base
)
371 unsigned long pfn
, va
;
378 * Remove any mappings which extend past the end of physical
379 * memory from the boot time page table:
381 for (pfn
= max_low_pfn
+ 1; pfn
< 1<<(32-PAGE_SHIFT
); pfn
++) {
382 va
= PAGE_OFFSET
+ (pfn
<<PAGE_SHIFT
);
383 pgd
= base
+ pgd_index(va
);
384 if (!pgd_present(*pgd
))
387 pud
= pud_offset(pgd
, va
);
388 pmd
= pmd_offset(pud
, va
);
389 if (!pmd_present(*pmd
))
392 pte
= pte_offset_kernel(pmd
, va
);
393 if (!pte_present(*pte
))
396 pte_clear(NULL
, va
, pte
);
398 paravirt_alloc_pmd(&init_mm
, __pa(base
) >> PAGE_SHIFT
);
401 void __init
native_pagetable_setup_done(pgd_t
*base
)
406 * Build a proper pagetable for the kernel mappings. Up until this
407 * point, we've been running on some set of pagetables constructed by
410 * If we're booting on native hardware, this will be a pagetable
411 * constructed in arch/x86/kernel/head_32.S. The root of the
412 * pagetable will be swapper_pg_dir.
414 * If we're booting paravirtualized under a hypervisor, then there are
415 * more options: we may already be running PAE, and the pagetable may
416 * or may not be based in swapper_pg_dir. In any case,
417 * paravirt_pagetable_setup_start() will set up swapper_pg_dir
418 * appropriately for the rest of the initialization to work.
420 * In general, pagetable_init() assumes that the pagetable may already
421 * be partially populated, and so it avoids stomping on any existing
424 static void __init
pagetable_init(void)
426 pgd_t
*pgd_base
= swapper_pg_dir
;
427 unsigned long vaddr
, end
;
429 paravirt_pagetable_setup_start(pgd_base
);
431 /* Enable PSE if available */
433 set_in_cr4(X86_CR4_PSE
);
435 /* Enable PGE if available */
437 set_in_cr4(X86_CR4_PGE
);
438 __PAGE_KERNEL
|= _PAGE_GLOBAL
;
439 __PAGE_KERNEL_EXEC
|= _PAGE_GLOBAL
;
442 kernel_physical_mapping_init(pgd_base
);
446 * Fixed mappings, only the page table structure has to be
447 * created - mappings will be set by set_fixmap():
449 early_ioremap_clear();
450 vaddr
= __fix_to_virt(__end_of_fixed_addresses
- 1) & PMD_MASK
;
451 end
= (FIXADDR_TOP
+ PMD_SIZE
- 1) & PMD_MASK
;
452 page_table_range_init(vaddr
, end
, pgd_base
);
453 early_ioremap_reset();
455 permanent_kmaps_init(pgd_base
);
457 paravirt_pagetable_setup_done(pgd_base
);
460 #ifdef CONFIG_ACPI_SLEEP
462 * ACPI suspend needs this for resume, because things like the intel-agp
463 * driver might have split up a kernel 4MB mapping.
465 char swsusp_pg_dir
[PAGE_SIZE
]
466 __attribute__ ((aligned(PAGE_SIZE
)));
468 static inline void save_pg_dir(void)
470 memcpy(swsusp_pg_dir
, swapper_pg_dir
, PAGE_SIZE
);
472 #else /* !CONFIG_ACPI_SLEEP */
473 static inline void save_pg_dir(void)
476 #endif /* !CONFIG_ACPI_SLEEP */
478 void zap_low_mappings(void)
483 * Zap initial low-memory mappings.
485 * Note that "pgd_clear()" doesn't do it for
486 * us, because pgd_clear() is a no-op on i386.
488 for (i
= 0; i
< KERNEL_PGD_BOUNDARY
; i
++) {
489 #ifdef CONFIG_X86_PAE
490 set_pgd(swapper_pg_dir
+i
, __pgd(1 + __pa(empty_zero_page
)));
492 set_pgd(swapper_pg_dir
+i
, __pgd(0));
500 pteval_t __supported_pte_mask __read_mostly
= ~_PAGE_NX
;
501 EXPORT_SYMBOL_GPL(__supported_pte_mask
);
503 #ifdef CONFIG_X86_PAE
505 static int disable_nx __initdata
;
510 * Control non executable mappings.
515 static int __init
noexec_setup(char *str
)
517 if (!str
|| !strcmp(str
, "on")) {
519 __supported_pte_mask
|= _PAGE_NX
;
523 if (!strcmp(str
, "off")) {
525 __supported_pte_mask
&= ~_PAGE_NX
;
533 early_param("noexec", noexec_setup
);
535 static void __init
set_nx(void)
537 unsigned int v
[4], l
, h
;
539 if (cpu_has_pae
&& (cpuid_eax(0x80000000) > 0x80000001)) {
540 cpuid(0x80000001, &v
[0], &v
[1], &v
[2], &v
[3]);
542 if ((v
[3] & (1 << 20)) && !disable_nx
) {
543 rdmsr(MSR_EFER
, l
, h
);
545 wrmsr(MSR_EFER
, l
, h
);
547 __supported_pte_mask
|= _PAGE_NX
;
554 * paging_init() sets up the page tables - note that the first 8MB are
555 * already mapped by head.S.
557 * This routines also unmaps the page at virtual kernel address 0, so
558 * that we can trap those pesky NULL-reference errors in the kernel.
560 void __init
paging_init(void)
562 #ifdef CONFIG_X86_PAE
565 printk(KERN_INFO
"NX (Execute Disable) protection: active\n");
569 load_cr3(swapper_pg_dir
);
577 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
578 * and also on some strange 486's. All 586+'s are OK. This used to involve
579 * black magic jumps to work around some nasty CPU bugs, but fortunately the
580 * switch to using exceptions got rid of all that.
582 static void __init
test_wp_bit(void)
585 "Checking if this processor honours the WP bit even in supervisor mode...");
587 /* Any page-aligned address will do, the test is non-destructive */
588 __set_fixmap(FIX_WP_TEST
, __pa(&swapper_pg_dir
), PAGE_READONLY
);
589 boot_cpu_data
.wp_works_ok
= do_test_wp_bit();
590 clear_fixmap(FIX_WP_TEST
);
592 if (!boot_cpu_data
.wp_works_ok
) {
593 printk(KERN_CONT
"No.\n");
594 #ifdef CONFIG_X86_WP_WORKS_OK
596 "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
599 printk(KERN_CONT
"Ok.\n");
603 static struct kcore_list kcore_mem
, kcore_vmalloc
;
605 void __init
mem_init(void)
607 int codesize
, reservedpages
, datasize
, initsize
;
610 #ifdef CONFIG_FLATMEM
613 bad_ppro
= ppro_with_ram_bug();
615 #ifdef CONFIG_HIGHMEM
616 /* check that fixmap and pkmap do not overlap */
617 if (PKMAP_BASE
+ LAST_PKMAP
*PAGE_SIZE
>= FIXADDR_START
) {
619 "fixmap and kmap areas overlap - this will crash\n");
620 printk(KERN_ERR
"pkstart: %lxh pkend: %lxh fixstart %lxh\n",
621 PKMAP_BASE
, PKMAP_BASE
+ LAST_PKMAP
*PAGE_SIZE
,
626 /* this will put all low memory onto the freelists */
627 totalram_pages
+= free_all_bootmem();
630 for (tmp
= 0; tmp
< max_low_pfn
; tmp
++)
632 * Only count reserved RAM pages:
634 if (page_is_ram(tmp
) && PageReserved(pfn_to_page(tmp
)))
637 set_highmem_pages_init(bad_ppro
);
639 codesize
= (unsigned long) &_etext
- (unsigned long) &_text
;
640 datasize
= (unsigned long) &_edata
- (unsigned long) &_etext
;
641 initsize
= (unsigned long) &__init_end
- (unsigned long) &__init_begin
;
643 kclist_add(&kcore_mem
, __va(0), max_low_pfn
<< PAGE_SHIFT
);
644 kclist_add(&kcore_vmalloc
, (void *)VMALLOC_START
,
645 VMALLOC_END
-VMALLOC_START
);
647 printk(KERN_INFO
"Memory: %luk/%luk available (%dk kernel code, "
648 "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
649 (unsigned long) nr_free_pages() << (PAGE_SHIFT
-10),
650 num_physpages
<< (PAGE_SHIFT
-10),
652 reservedpages
<< (PAGE_SHIFT
-10),
655 (unsigned long) (totalhigh_pages
<< (PAGE_SHIFT
-10))
658 #if 1 /* double-sanity-check paranoia */
659 printk(KERN_INFO
"virtual kernel memory layout:\n"
660 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
661 #ifdef CONFIG_HIGHMEM
662 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
664 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
665 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
666 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
667 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
668 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
669 FIXADDR_START
, FIXADDR_TOP
,
670 (FIXADDR_TOP
- FIXADDR_START
) >> 10,
672 #ifdef CONFIG_HIGHMEM
673 PKMAP_BASE
, PKMAP_BASE
+LAST_PKMAP
*PAGE_SIZE
,
674 (LAST_PKMAP
*PAGE_SIZE
) >> 10,
677 VMALLOC_START
, VMALLOC_END
,
678 (VMALLOC_END
- VMALLOC_START
) >> 20,
680 (unsigned long)__va(0), (unsigned long)high_memory
,
681 ((unsigned long)high_memory
- (unsigned long)__va(0)) >> 20,
683 (unsigned long)&__init_begin
, (unsigned long)&__init_end
,
684 ((unsigned long)&__init_end
-
685 (unsigned long)&__init_begin
) >> 10,
687 (unsigned long)&_etext
, (unsigned long)&_edata
,
688 ((unsigned long)&_edata
- (unsigned long)&_etext
) >> 10,
690 (unsigned long)&_text
, (unsigned long)&_etext
,
691 ((unsigned long)&_etext
- (unsigned long)&_text
) >> 10);
693 #ifdef CONFIG_HIGHMEM
694 BUG_ON(PKMAP_BASE
+ LAST_PKMAP
*PAGE_SIZE
> FIXADDR_START
);
695 BUG_ON(VMALLOC_END
> PKMAP_BASE
);
697 BUG_ON(VMALLOC_START
> VMALLOC_END
);
698 BUG_ON((unsigned long)high_memory
> VMALLOC_START
);
699 #endif /* double-sanity-check paranoia */
701 if (boot_cpu_data
.wp_works_ok
< 0)
709 #ifdef CONFIG_MEMORY_HOTPLUG
710 int arch_add_memory(int nid
, u64 start
, u64 size
)
712 struct pglist_data
*pgdata
= NODE_DATA(nid
);
713 struct zone
*zone
= pgdata
->node_zones
+ ZONE_HIGHMEM
;
714 unsigned long start_pfn
= start
>> PAGE_SHIFT
;
715 unsigned long nr_pages
= size
>> PAGE_SHIFT
;
717 return __add_pages(zone
, start_pfn
, nr_pages
);
722 * This function cannot be __init, since exceptions don't work in that
723 * section. Put this after the callers, so that it cannot be inlined.
725 static noinline
int do_test_wp_bit(void)
730 __asm__
__volatile__(
736 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST
)),
745 #ifdef CONFIG_DEBUG_RODATA
746 const int rodata_test_data
= 0xC3;
747 EXPORT_SYMBOL_GPL(rodata_test_data
);
749 void mark_rodata_ro(void)
751 unsigned long start
= PFN_ALIGN(_text
);
752 unsigned long size
= PFN_ALIGN(_etext
) - start
;
754 set_pages_ro(virt_to_page(start
), size
>> PAGE_SHIFT
);
755 printk(KERN_INFO
"Write protecting the kernel text: %luk\n",
758 #ifdef CONFIG_CPA_DEBUG
759 printk(KERN_INFO
"Testing CPA: Reverting %lx-%lx\n",
761 set_pages_rw(virt_to_page(start
), size
>>PAGE_SHIFT
);
763 printk(KERN_INFO
"Testing CPA: write protecting again\n");
764 set_pages_ro(virt_to_page(start
), size
>>PAGE_SHIFT
);
767 size
= (unsigned long)__end_rodata
- start
;
768 set_pages_ro(virt_to_page(start
), size
>> PAGE_SHIFT
);
769 printk(KERN_INFO
"Write protecting the kernel read-only data: %luk\n",
773 #ifdef CONFIG_CPA_DEBUG
774 printk(KERN_INFO
"Testing CPA: undo %lx-%lx\n", start
, start
+ size
);
775 set_pages_rw(virt_to_page(start
), size
>> PAGE_SHIFT
);
777 printk(KERN_INFO
"Testing CPA: write protecting again\n");
778 set_pages_ro(virt_to_page(start
), size
>> PAGE_SHIFT
);
783 void free_init_pages(char *what
, unsigned long begin
, unsigned long end
)
785 #ifdef CONFIG_DEBUG_PAGEALLOC
787 * If debugging page accesses then do not free this memory but
788 * mark them not present - any buggy init-section access will
789 * create a kernel page fault:
791 printk(KERN_INFO
"debug: unmapping init memory %08lx..%08lx\n",
792 begin
, PAGE_ALIGN(end
));
793 set_memory_np(begin
, (end
- begin
) >> PAGE_SHIFT
);
798 * We just marked the kernel text read only above, now that
799 * we are going to free part of that, we need to make that
802 set_memory_rw(begin
, (end
- begin
) >> PAGE_SHIFT
);
804 for (addr
= begin
; addr
< end
; addr
+= PAGE_SIZE
) {
805 ClearPageReserved(virt_to_page(addr
));
806 init_page_count(virt_to_page(addr
));
807 memset((void *)addr
, POISON_FREE_INITMEM
, PAGE_SIZE
);
811 printk(KERN_INFO
"Freeing %s: %luk freed\n", what
, (end
- begin
) >> 10);
815 void free_initmem(void)
817 free_init_pages("unused kernel memory",
818 (unsigned long)(&__init_begin
),
819 (unsigned long)(&__init_end
));
822 #ifdef CONFIG_BLK_DEV_INITRD
823 void free_initrd_mem(unsigned long start
, unsigned long end
)
825 free_init_pages("initrd memory", start
, end
);
829 int __init
reserve_bootmem_generic(unsigned long phys
, unsigned long len
,
832 return reserve_bootmem(phys
, len
, flags
);