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TOMOYO Linux Cross Reference
Linux/arch/um/kernel/mem.c

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  1 /*
  2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  3  * Licensed under the GPL
  4  */
  5 
  6 #include <linux/stddef.h>
  7 #include <linux/module.h>
  8 #include <linux/bootmem.h>
  9 #include <linux/highmem.h>
 10 #include <linux/mm.h>
 11 #include <linux/swap.h>
 12 #include <linux/slab.h>
 13 #include <asm/fixmap.h>
 14 #include <asm/page.h>
 15 #include <as-layout.h>
 16 #include <init.h>
 17 #include <kern.h>
 18 #include <kern_util.h>
 19 #include <mem_user.h>
 20 #include <os.h>
 21 
 22 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
 23 unsigned long *empty_zero_page = NULL;
 24 EXPORT_SYMBOL(empty_zero_page);
 25 /* allocated in paging_init and unchanged thereafter */
 26 static unsigned long *empty_bad_page = NULL;
 27 
 28 /*
 29  * Initialized during boot, and readonly for initializing page tables
 30  * afterwards
 31  */
 32 pgd_t swapper_pg_dir[PTRS_PER_PGD];
 33 
 34 /* Initialized at boot time, and readonly after that */
 35 unsigned long long highmem;
 36 int kmalloc_ok = 0;
 37 
 38 /* Used during early boot */
 39 static unsigned long brk_end;
 40 
 41 void __init mem_init(void)
 42 {
 43         /* clear the zero-page */
 44         memset(empty_zero_page, 0, PAGE_SIZE);
 45 
 46         /* Map in the area just after the brk now that kmalloc is about
 47          * to be turned on.
 48          */
 49         brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
 50         map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
 51         free_bootmem(__pa(brk_end), uml_reserved - brk_end);
 52         uml_reserved = brk_end;
 53 
 54         /* this will put all low memory onto the freelists */
 55         free_all_bootmem();
 56         max_low_pfn = totalram_pages;
 57         max_pfn = totalram_pages;
 58         mem_init_print_info(NULL);
 59         kmalloc_ok = 1;
 60 }
 61 
 62 /*
 63  * Create a page table and place a pointer to it in a middle page
 64  * directory entry.
 65  */
 66 static void __init one_page_table_init(pmd_t *pmd)
 67 {
 68         if (pmd_none(*pmd)) {
 69                 pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 70                 set_pmd(pmd, __pmd(_KERNPG_TABLE +
 71                                            (unsigned long) __pa(pte)));
 72                 if (pte != pte_offset_kernel(pmd, 0))
 73                         BUG();
 74         }
 75 }
 76 
 77 static void __init one_md_table_init(pud_t *pud)
 78 {
 79 #ifdef CONFIG_3_LEVEL_PGTABLES
 80         pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 81         set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 82         if (pmd_table != pmd_offset(pud, 0))
 83                 BUG();
 84 #endif
 85 }
 86 
 87 static void __init fixrange_init(unsigned long start, unsigned long end,
 88                                  pgd_t *pgd_base)
 89 {
 90         pgd_t *pgd;
 91         pud_t *pud;
 92         pmd_t *pmd;
 93         int i, j;
 94         unsigned long vaddr;
 95 
 96         vaddr = start;
 97         i = pgd_index(vaddr);
 98         j = pmd_index(vaddr);
 99         pgd = pgd_base + i;
100 
101         for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
102                 pud = pud_offset(pgd, vaddr);
103                 if (pud_none(*pud))
104                         one_md_table_init(pud);
105                 pmd = pmd_offset(pud, vaddr);
106                 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
107                         one_page_table_init(pmd);
108                         vaddr += PMD_SIZE;
109                 }
110                 j = 0;
111         }
112 }
113 
114 static void __init fixaddr_user_init( void)
115 {
116 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
117         long size = FIXADDR_USER_END - FIXADDR_USER_START;
118         pgd_t *pgd;
119         pud_t *pud;
120         pmd_t *pmd;
121         pte_t *pte;
122         phys_t p;
123         unsigned long v, vaddr = FIXADDR_USER_START;
124 
125         if (!size)
126                 return;
127 
128         fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
129         v = (unsigned long) alloc_bootmem_low_pages(size);
130         memcpy((void *) v , (void *) FIXADDR_USER_START, size);
131         p = __pa(v);
132         for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
133                       p += PAGE_SIZE) {
134                 pgd = swapper_pg_dir + pgd_index(vaddr);
135                 pud = pud_offset(pgd, vaddr);
136                 pmd = pmd_offset(pud, vaddr);
137                 pte = pte_offset_kernel(pmd, vaddr);
138                 pte_set_val(*pte, p, PAGE_READONLY);
139         }
140 #endif
141 }
142 
143 void __init paging_init(void)
144 {
145         unsigned long zones_size[MAX_NR_ZONES], vaddr;
146         int i;
147 
148         empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
149         empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
150         for (i = 0; i < ARRAY_SIZE(zones_size); i++)
151                 zones_size[i] = 0;
152 
153         zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
154                 (uml_physmem >> PAGE_SHIFT);
155         free_area_init(zones_size);
156 
157         /*
158          * Fixed mappings, only the page table structure has to be
159          * created - mappings will be set by set_fixmap():
160          */
161         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
162         fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
163 
164         fixaddr_user_init();
165 }
166 
167 /*
168  * This can't do anything because nothing in the kernel image can be freed
169  * since it's not in kernel physical memory.
170  */
171 
172 void free_initmem(void)
173 {
174 }
175 
176 #ifdef CONFIG_BLK_DEV_INITRD
177 void free_initrd_mem(unsigned long start, unsigned long end)
178 {
179         free_reserved_area((void *)start, (void *)end, -1, "initrd");
180 }
181 #endif
182 
183 /* Allocate and free page tables. */
184 
185 pgd_t *pgd_alloc(struct mm_struct *mm)
186 {
187         pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
188 
189         if (pgd) {
190                 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
191                 memcpy(pgd + USER_PTRS_PER_PGD,
192                        swapper_pg_dir + USER_PTRS_PER_PGD,
193                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
194         }
195         return pgd;
196 }
197 
198 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
199 {
200         free_page((unsigned long) pgd);
201 }
202 
203 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
204 {
205         pte_t *pte;
206 
207         pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
208         return pte;
209 }
210 
211 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
212 {
213         struct page *pte;
214 
215         pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
216         if (!pte)
217                 return NULL;
218         if (!pgtable_page_ctor(pte)) {
219                 __free_page(pte);
220                 return NULL;
221         }
222         return pte;
223 }
224 
225 #ifdef CONFIG_3_LEVEL_PGTABLES
226 pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
227 {
228         pmd_t *pmd = (pmd_t *) __get_free_page(GFP_KERNEL);
229 
230         if (pmd)
231                 memset(pmd, 0, PAGE_SIZE);
232 
233         return pmd;
234 }
235 #endif
236 
237 void *uml_kmalloc(int size, int flags)
238 {
239         return kmalloc(size, flags);
240 }
241 

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