Linux Kernel  3.7.1
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init.c
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1 #include <linux/gfp.h>
2 #include <linux/initrd.h>
3 #include <linux/ioport.h>
4 #include <linux/swap.h>
5 #include <linux/memblock.h>
6 #include <linux/bootmem.h> /* for max_low_pfn */
7 
8 #include <asm/cacheflush.h>
9 #include <asm/e820.h>
10 #include <asm/init.h>
11 #include <asm/page.h>
12 #include <asm/page_types.h>
13 #include <asm/sections.h>
14 #include <asm/setup.h>
15 #include <asm/tlbflush.h>
16 #include <asm/tlb.h>
17 #include <asm/proto.h>
18 #include <asm/dma.h> /* for MAX_DMA_PFN */
19 
20 unsigned long __initdata pgt_buf_start;
21 unsigned long __meminitdata pgt_buf_end;
22 unsigned long __meminitdata pgt_buf_top;
23 
25 
27 #ifdef CONFIG_DIRECT_GBPAGES
28  = 1
29 #endif
30 ;
31 
32 struct map_range {
33  unsigned long start;
34  unsigned long end;
35  unsigned page_size_mask;
36 };
37 
38 /*
39  * First calculate space needed for kernel direct mapping page tables to cover
40  * mr[0].start to mr[nr_range - 1].end, while accounting for possible 2M and 1GB
41  * pages. Then find enough contiguous space for those page tables.
42  */
43 static void __init find_early_table_space(struct map_range *mr, int nr_range)
44 {
45  int i;
46  unsigned long puds = 0, pmds = 0, ptes = 0, tables;
47  unsigned long start = 0, good_end;
49 
50  for (i = 0; i < nr_range; i++) {
51  unsigned long range, extra;
52 
53  range = mr[i].end - mr[i].start;
54  puds += (range + PUD_SIZE - 1) >> PUD_SHIFT;
55 
56  if (mr[i].page_size_mask & (1 << PG_LEVEL_1G)) {
57  extra = range - ((range >> PUD_SHIFT) << PUD_SHIFT);
58  pmds += (extra + PMD_SIZE - 1) >> PMD_SHIFT;
59  } else {
60  pmds += (range + PMD_SIZE - 1) >> PMD_SHIFT;
61  }
62 
63  if (mr[i].page_size_mask & (1 << PG_LEVEL_2M)) {
64  extra = range - ((range >> PMD_SHIFT) << PMD_SHIFT);
65 #ifdef CONFIG_X86_32
66  extra += PMD_SIZE;
67 #endif
68  ptes += (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
69  } else {
70  ptes += (range + PAGE_SIZE - 1) >> PAGE_SHIFT;
71  }
72  }
73 
74  tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
75  tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
76  tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
77 
78 #ifdef CONFIG_X86_32
79  /* for fixmap */
81 #endif
82  good_end = max_pfn_mapped << PAGE_SHIFT;
83 
84  base = memblock_find_in_range(start, good_end, tables, PAGE_SIZE);
85  if (!base)
86  panic("Cannot find space for the kernel page tables");
87 
88  pgt_buf_start = base >> PAGE_SHIFT;
91 
92  printk(KERN_DEBUG "kernel direct mapping tables up to %#lx @ [mem %#010lx-%#010lx]\n",
93  mr[nr_range - 1].end - 1, pgt_buf_start << PAGE_SHIFT,
94  (pgt_buf_top << PAGE_SHIFT) - 1);
95 }
96 
98 {
99  memblock_reserve(start, end - start);
100 }
101 
102 #ifdef CONFIG_X86_32
103 #define NR_RANGE_MR 3
104 #else /* CONFIG_X86_64 */
105 #define NR_RANGE_MR 5
106 #endif
107 
108 static int __meminit save_mr(struct map_range *mr, int nr_range,
109  unsigned long start_pfn, unsigned long end_pfn,
110  unsigned long page_size_mask)
111 {
112  if (start_pfn < end_pfn) {
113  if (nr_range >= NR_RANGE_MR)
114  panic("run out of range for init_memory_mapping\n");
115  mr[nr_range].start = start_pfn<<PAGE_SHIFT;
116  mr[nr_range].end = end_pfn<<PAGE_SHIFT;
117  mr[nr_range].page_size_mask = page_size_mask;
118  nr_range++;
119  }
120 
121  return nr_range;
122 }
123 
124 /*
125  * Setup the direct mapping of the physical memory at PAGE_OFFSET.
126  * This runs before bootmem is initialized and gets pages directly from
127  * the physical memory. To access them they are temporarily mapped.
128  */
129 unsigned long __init_refok init_memory_mapping(unsigned long start,
130  unsigned long end)
131 {
132  unsigned long page_size_mask = 0;
133  unsigned long start_pfn, end_pfn;
134  unsigned long ret = 0;
135  unsigned long pos;
136 
137  struct map_range mr[NR_RANGE_MR];
138  int nr_range, i;
139  int use_pse, use_gbpages;
140 
141  printk(KERN_INFO "init_memory_mapping: [mem %#010lx-%#010lx]\n",
142  start, end - 1);
143 
144 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
145  /*
146  * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
147  * This will simplify cpa(), which otherwise needs to support splitting
148  * large pages into small in interrupt context, etc.
149  */
150  use_pse = use_gbpages = 0;
151 #else
152  use_pse = cpu_has_pse;
153  use_gbpages = direct_gbpages;
154 #endif
155 
156  /* Enable PSE if available */
157  if (cpu_has_pse)
158  set_in_cr4(X86_CR4_PSE);
159 
160  /* Enable PGE if available */
161  if (cpu_has_pge) {
162  set_in_cr4(X86_CR4_PGE);
164  }
165 
166  if (use_gbpages)
167  page_size_mask |= 1 << PG_LEVEL_1G;
168  if (use_pse)
169  page_size_mask |= 1 << PG_LEVEL_2M;
170 
171  memset(mr, 0, sizeof(mr));
172  nr_range = 0;
173 
174  /* head if not big page alignment ? */
175  start_pfn = start >> PAGE_SHIFT;
176  pos = start_pfn << PAGE_SHIFT;
177 #ifdef CONFIG_X86_32
178  /*
179  * Don't use a large page for the first 2/4MB of memory
180  * because there are often fixed size MTRRs in there
181  * and overlapping MTRRs into large pages can cause
182  * slowdowns.
183  */
184  if (pos == 0)
185  end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
186  else
187  end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
188  << (PMD_SHIFT - PAGE_SHIFT);
189 #else /* CONFIG_X86_64 */
190  end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)
191  << (PMD_SHIFT - PAGE_SHIFT);
192 #endif
193  if (end_pfn > (end >> PAGE_SHIFT))
194  end_pfn = end >> PAGE_SHIFT;
195  if (start_pfn < end_pfn) {
196  nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
197  pos = end_pfn << PAGE_SHIFT;
198  }
199 
200  /* big page (2M) range */
201  start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
202  << (PMD_SHIFT - PAGE_SHIFT);
203 #ifdef CONFIG_X86_32
204  end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
205 #else /* CONFIG_X86_64 */
206  end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
207  << (PUD_SHIFT - PAGE_SHIFT);
208  if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)))
209  end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT));
210 #endif
211 
212  if (start_pfn < end_pfn) {
213  nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
214  page_size_mask & (1<<PG_LEVEL_2M));
215  pos = end_pfn << PAGE_SHIFT;
216  }
217 
218 #ifdef CONFIG_X86_64
219  /* big page (1G) range */
220  start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
221  << (PUD_SHIFT - PAGE_SHIFT);
222  end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
223  if (start_pfn < end_pfn) {
224  nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
225  page_size_mask &
226  ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
227  pos = end_pfn << PAGE_SHIFT;
228  }
229 
230  /* tail is not big page (1G) alignment */
231  start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
232  << (PMD_SHIFT - PAGE_SHIFT);
233  end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
234  if (start_pfn < end_pfn) {
235  nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
236  page_size_mask & (1<<PG_LEVEL_2M));
237  pos = end_pfn << PAGE_SHIFT;
238  }
239 #endif
240 
241  /* tail is not big page (2M) alignment */
242  start_pfn = pos>>PAGE_SHIFT;
243  end_pfn = end>>PAGE_SHIFT;
244  nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
245 
246  /* try to merge same page size and continuous */
247  for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
248  unsigned long old_start;
249  if (mr[i].end != mr[i+1].start ||
250  mr[i].page_size_mask != mr[i+1].page_size_mask)
251  continue;
252  /* move it */
253  old_start = mr[i].start;
254  memmove(&mr[i], &mr[i+1],
255  (nr_range - 1 - i) * sizeof(struct map_range));
256  mr[i--].start = old_start;
257  nr_range--;
258  }
259 
260  for (i = 0; i < nr_range; i++)
261  printk(KERN_DEBUG " [mem %#010lx-%#010lx] page %s\n",
262  mr[i].start, mr[i].end - 1,
263  (mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
264  (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
265 
266  /*
267  * Find space for the kernel direct mapping tables.
268  *
269  * Later we should allocate these tables in the local node of the
270  * memory mapped. Unfortunately this is done currently before the
271  * nodes are discovered.
272  */
273  if (!after_bootmem)
274  find_early_table_space(mr, nr_range);
275 
276  for (i = 0; i < nr_range; i++)
277  ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
278  mr[i].page_size_mask);
279 
280 #ifdef CONFIG_X86_32
282 
283  load_cr3(swapper_pg_dir);
284 #endif
285 
286  __flush_tlb_all();
287 
288  /*
289  * Reserve the kernel pagetable pages we used (pgt_buf_start -
290  * pgt_buf_end) and free the other ones (pgt_buf_end - pgt_buf_top)
291  * so that they can be reused for other purposes.
292  *
293  * On native it just means calling memblock_reserve, on Xen it also
294  * means marking RW the pagetable pages that we allocated before
295  * but that haven't been used.
296  *
297  * In fact on xen we mark RO the whole range pgt_buf_start -
298  * pgt_buf_top, because we have to make sure that when
299  * init_memory_mapping reaches the pagetable pages area, it maps
300  * RO all the pagetable pages, including the ones that are beyond
301  * pgt_buf_end at that time.
302  */
304  x86_init.mapping.pagetable_reserve(PFN_PHYS(pgt_buf_start),
306 
307  if (!after_bootmem)
308  early_memtest(start, end);
309 
310  return ret >> PAGE_SHIFT;
311 }
312 
313 
314 /*
315  * devmem_is_allowed() checks to see if /dev/mem access to a certain address
316  * is valid. The argument is a physical page number.
317  *
318  *
319  * On x86, access has to be given to the first megabyte of ram because that area
320  * contains bios code and data regions used by X and dosemu and similar apps.
321  * Access has to be given to non-kernel-ram areas as well, these contain the PCI
322  * mmio resources as well as potential bios/acpi data regions.
323  */
324 int devmem_is_allowed(unsigned long pagenr)
325 {
326  if (pagenr < 256)
327  return 1;
328  if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
329  return 0;
330  if (!page_is_ram(pagenr))
331  return 1;
332  return 0;
333 }
334 
335 void free_init_pages(char *what, unsigned long begin, unsigned long end)
336 {
337  unsigned long addr;
338  unsigned long begin_aligned, end_aligned;
339 
340  /* Make sure boundaries are page aligned */
341  begin_aligned = PAGE_ALIGN(begin);
342  end_aligned = end & PAGE_MASK;
343 
344  if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
345  begin = begin_aligned;
346  end = end_aligned;
347  }
348 
349  if (begin >= end)
350  return;
351 
352  addr = begin;
353 
354  /*
355  * If debugging page accesses then do not free this memory but
356  * mark them not present - any buggy init-section access will
357  * create a kernel page fault:
358  */
359 #ifdef CONFIG_DEBUG_PAGEALLOC
360  printk(KERN_INFO "debug: unmapping init [mem %#010lx-%#010lx]\n",
361  begin, end - 1);
362  set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
363 #else
364  /*
365  * We just marked the kernel text read only above, now that
366  * we are going to free part of that, we need to make that
367  * writeable and non-executable first.
368  */
369  set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
370  set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
371 
372  printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
373 
374  for (; addr < end; addr += PAGE_SIZE) {
375  ClearPageReserved(virt_to_page(addr));
376  init_page_count(virt_to_page(addr));
377  memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
378  free_page(addr);
379  totalram_pages++;
380  }
381 #endif
382 }
383 
384 void free_initmem(void)
385 {
386  free_init_pages("unused kernel memory",
387  (unsigned long)(&__init_begin),
388  (unsigned long)(&__init_end));
389 }
390 
391 #ifdef CONFIG_BLK_DEV_INITRD
392 void __init free_initrd_mem(unsigned long start, unsigned long end)
393 {
394  /*
395  * end could be not aligned, and We can not align that,
396  * decompresser could be confused by aligned initrd_end
397  * We already reserve the end partial page before in
398  * - i386_start_kernel()
399  * - x86_64_start_kernel()
400  * - relocate_initrd()
401  * So here We can do PAGE_ALIGN() safely to get partial page to be freed
402  */
403  free_init_pages("initrd memory", start, PAGE_ALIGN(end));
404 }
405 #endif
406 
408 {
409  unsigned long max_zone_pfns[MAX_NR_ZONES];
410 
411  memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
412 
413 #ifdef CONFIG_ZONE_DMA
414  max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
415 #endif
416 #ifdef CONFIG_ZONE_DMA32
417  max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
418 #endif
419  max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
420 #ifdef CONFIG_HIGHMEM
421  max_zone_pfns[ZONE_HIGHMEM] = max_pfn;
422 #endif
423 
424  free_area_init_nodes(max_zone_pfns);
425 }
426