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Christoph Lameter8f6aac42007-10-16 01:24:13 -07001/*
2 * Virtual Memory Map support
3 *
Christoph Lametercde53532008-07-04 09:59:22 -07004 * (C) 2007 sgi. Christoph Lameter.
Christoph Lameter8f6aac42007-10-16 01:24:13 -07005 *
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.
9 *
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.
16 *
Andy Whitcroft29c71112007-10-16 01:24:14 -070017 * The architecture is expected to provide a vmemmap_populate() function
18 * to instantiate the mapping.
Christoph Lameter8f6aac42007-10-16 01:24:13 -070019 */
20#include <linux/mm.h>
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>
Glauber de Oliveira Costa8bca44b2007-10-29 14:37:19 -070027#include <linux/sched.h>
Christoph Lameter8f6aac42007-10-16 01:24:13 -070028#include <asm/dma.h>
29#include <asm/pgalloc.h>
30#include <asm/pgtable.h>
31
32/*
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.
36 */
KAMEZAWA Hiroyukie0dc3a52007-11-28 16:21:57 -080037
38static void * __init_refok __earlyonly_bootmem_alloc(int node,
39 unsigned long size,
40 unsigned long align,
41 unsigned long goal)
42{
43 return __alloc_bootmem_node(NODE_DATA(node), size, align, goal);
44}
45
46
Christoph Lameter8f6aac42007-10-16 01:24:13 -070047void * __meminit vmemmap_alloc_block(unsigned long size, int node)
48{
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));
53 if (page)
54 return page_address(page);
55 return NULL;
56 } else
KAMEZAWA Hiroyukie0dc3a52007-11-28 16:21:57 -080057 return __earlyonly_bootmem_alloc(node, size, size,
Christoph Lameter8f6aac42007-10-16 01:24:13 -070058 __pa(MAX_DMA_ADDRESS));
59}
60
Christoph Lameter8f6aac42007-10-16 01:24:13 -070061void __meminit vmemmap_verify(pte_t *pte, int node,
62 unsigned long start, unsigned long end)
63{
64 unsigned long pfn = pte_pfn(*pte);
65 int actual_node = early_pfn_to_nid(pfn);
66
David Rientjesb41ad142008-11-06 12:53:31 -080067 if (node_distance(actual_node, node) > LOCAL_DISTANCE)
Christoph Lameter8f6aac42007-10-16 01:24:13 -070068 printk(KERN_WARNING "[%lx-%lx] potential offnode "
69 "page_structs\n", start, end - 1);
70}
71
Andy Whitcroft29c71112007-10-16 01:24:14 -070072pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node)
Christoph Lameter8f6aac42007-10-16 01:24:13 -070073{
Andy Whitcroft29c71112007-10-16 01:24:14 -070074 pte_t *pte = pte_offset_kernel(pmd, addr);
75 if (pte_none(*pte)) {
76 pte_t entry;
77 void *p = vmemmap_alloc_block(PAGE_SIZE, node);
78 if (!p)
Al Viro9dce07f2008-03-29 03:07:28 +000079 return NULL;
Andy Whitcroft29c71112007-10-16 01:24:14 -070080 entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
81 set_pte_at(&init_mm, addr, pte, entry);
82 }
83 return pte;
84}
85
86pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
87{
88 pmd_t *pmd = pmd_offset(pud, addr);
89 if (pmd_none(*pmd)) {
90 void *p = vmemmap_alloc_block(PAGE_SIZE, node);
91 if (!p)
Al Viro9dce07f2008-03-29 03:07:28 +000092 return NULL;
Andy Whitcroft29c71112007-10-16 01:24:14 -070093 pmd_populate_kernel(&init_mm, pmd, p);
94 }
95 return pmd;
96}
97
98pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node)
99{
100 pud_t *pud = pud_offset(pgd, addr);
101 if (pud_none(*pud)) {
102 void *p = vmemmap_alloc_block(PAGE_SIZE, node);
103 if (!p)
Al Viro9dce07f2008-03-29 03:07:28 +0000104 return NULL;
Andy Whitcroft29c71112007-10-16 01:24:14 -0700105 pud_populate(&init_mm, pud, p);
106 }
107 return pud;
108}
109
110pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
111{
112 pgd_t *pgd = pgd_offset_k(addr);
113 if (pgd_none(*pgd)) {
114 void *p = vmemmap_alloc_block(PAGE_SIZE, node);
115 if (!p)
Al Viro9dce07f2008-03-29 03:07:28 +0000116 return NULL;
Andy Whitcroft29c71112007-10-16 01:24:14 -0700117 pgd_populate(&init_mm, pgd, p);
118 }
119 return pgd;
120}
121
122int __meminit vmemmap_populate_basepages(struct page *start_page,
123 unsigned long size, int node)
124{
125 unsigned long addr = (unsigned long)start_page;
126 unsigned long end = (unsigned long)(start_page + size);
127 pgd_t *pgd;
128 pud_t *pud;
129 pmd_t *pmd;
Christoph Lameter8f6aac42007-10-16 01:24:13 -0700130 pte_t *pte;
131
Andy Whitcroft29c71112007-10-16 01:24:14 -0700132 for (; addr < end; addr += PAGE_SIZE) {
133 pgd = vmemmap_pgd_populate(addr, node);
134 if (!pgd)
135 return -ENOMEM;
136 pud = vmemmap_pud_populate(pgd, addr, node);
137 if (!pud)
138 return -ENOMEM;
139 pmd = vmemmap_pmd_populate(pud, addr, node);
140 if (!pmd)
141 return -ENOMEM;
142 pte = vmemmap_pte_populate(pmd, addr, node);
143 if (!pte)
144 return -ENOMEM;
145 vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
146 }
Christoph Lameter8f6aac42007-10-16 01:24:13 -0700147
148 return 0;
149}
150
Yasunori Goto98f3cfc2007-10-16 01:26:14 -0700151struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid)
Christoph Lameter8f6aac42007-10-16 01:24:13 -0700152{
153 struct page *map = pfn_to_page(pnum * PAGES_PER_SECTION);
154 int error = vmemmap_populate(map, PAGES_PER_SECTION, nid);
155 if (error)
156 return NULL;
157
158 return map;
159}