2 * Virtual Memory Map support
4 * (C) 2007 sgi. Christoph Lameter <clameter@sgi.com>.
6 * Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn,
7 * virt_to_page, page_address() to be implemented as a base offset
8 * calculation without memory access.
10 * However, virtual mappings need a page table and TLBs. Many Linux
11 * architectures already map their physical space using 1-1 mappings
12 * via TLBs. For those arches the virtual memmory map is essentially
13 * for free if we use the same page size as the 1-1 mappings. In that
14 * case the overhead consists of a few additional pages that are
15 * allocated to create a view of memory for vmemmap.
17 * The architecture is expected to provide a vmemmap_populate() function
18 * to instantiate the mapping.
21 #include <linux/mmzone.h>
22 #include <linux/bootmem.h>
23 #include <linux/highmem.h>
24 #include <linux/module.h>
25 #include <linux/spinlock.h>
26 #include <linux/vmalloc.h>
27 #include <linux/sched.h>
29 #include <asm/pgalloc.h>
30 #include <asm/pgtable.h>
33 * Allocate a block of memory to be used to back the virtual memory map
34 * or to back the page tables that are used to create the mapping.
35 * Uses the main allocators if they are available, else bootmem.
38 static void * __init_refok
__earlyonly_bootmem_alloc(int node
,
43 return __alloc_bootmem_node(NODE_DATA(node
), size
, align
, goal
);
47 void * __meminit
vmemmap_alloc_block(unsigned long size
, int node
)
49 /* If the main allocator is up use that, fallback to bootmem. */
50 if (slab_is_available()) {
51 struct page
*page
= alloc_pages_node(node
,
52 GFP_KERNEL
| __GFP_ZERO
, get_order(size
));
54 return page_address(page
);
57 return __earlyonly_bootmem_alloc(node
, size
, size
,
58 __pa(MAX_DMA_ADDRESS
));
61 void __meminit
vmemmap_verify(pte_t
*pte
, int node
,
62 unsigned long start
, unsigned long end
)
64 unsigned long pfn
= pte_pfn(*pte
);
65 int actual_node
= early_pfn_to_nid(pfn
);
67 if (actual_node
!= node
)
68 printk(KERN_WARNING
"[%lx-%lx] potential offnode "
69 "page_structs\n", start
, end
- 1);
72 pte_t
* __meminit
vmemmap_pte_populate(pmd_t
*pmd
, unsigned long addr
, int node
)
74 pte_t
*pte
= pte_offset_kernel(pmd
, addr
);
77 void *p
= vmemmap_alloc_block(PAGE_SIZE
, node
);
80 entry
= pfn_pte(__pa(p
) >> PAGE_SHIFT
, PAGE_KERNEL
);
81 set_pte_at(&init_mm
, addr
, pte
, entry
);
86 pmd_t
* __meminit
vmemmap_pmd_populate(pud_t
*pud
, unsigned long addr
, int node
)
88 pmd_t
*pmd
= pmd_offset(pud
, addr
);
90 void *p
= vmemmap_alloc_block(PAGE_SIZE
, node
);
93 pmd_populate_kernel(&init_mm
, pmd
, p
);
98 pud_t
* __meminit
vmemmap_pud_populate(pgd_t
*pgd
, unsigned long addr
, int node
)
100 pud_t
*pud
= pud_offset(pgd
, addr
);
101 if (pud_none(*pud
)) {
102 void *p
= vmemmap_alloc_block(PAGE_SIZE
, node
);
105 pud_populate(&init_mm
, pud
, p
);
110 pgd_t
* __meminit
vmemmap_pgd_populate(unsigned long addr
, int node
)
112 pgd_t
*pgd
= pgd_offset_k(addr
);
113 if (pgd_none(*pgd
)) {
114 void *p
= vmemmap_alloc_block(PAGE_SIZE
, node
);
117 pgd_populate(&init_mm
, pgd
, p
);
122 int __meminit
vmemmap_populate_basepages(struct page
*start_page
,
123 unsigned long size
, int node
)
125 unsigned long addr
= (unsigned long)start_page
;
126 unsigned long end
= (unsigned long)(start_page
+ size
);
132 for (; addr
< end
; addr
+= PAGE_SIZE
) {
133 pgd
= vmemmap_pgd_populate(addr
, node
);
136 pud
= vmemmap_pud_populate(pgd
, addr
, node
);
139 pmd
= vmemmap_pmd_populate(pud
, addr
, node
);
142 pte
= vmemmap_pte_populate(pmd
, addr
, node
);
145 vmemmap_verify(pte
, node
, addr
, addr
+ PAGE_SIZE
);
151 struct page
* __meminit
sparse_mem_map_populate(unsigned long pnum
, int nid
)
153 struct page
*map
= pfn_to_page(pnum
* PAGES_PER_SECTION
);
154 int error
= vmemmap_populate(map
, PAGES_PER_SECTION
, nid
);
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