Merge branch 'next-i2c' of git://aeryn.fluff.org.uk/bjdooks/linux
[linux-2.6] / arch / x86 / mm / init.c
1 #include <linux/initrd.h>
2 #include <linux/ioport.h>
3 #include <linux/swap.h>
4
5 #include <asm/cacheflush.h>
6 #include <asm/e820.h>
7 #include <asm/init.h>
8 #include <asm/page.h>
9 #include <asm/page_types.h>
10 #include <asm/sections.h>
11 #include <asm/setup.h>
12 #include <asm/system.h>
13 #include <asm/tlbflush.h>
14 #include <asm/tlb.h>
15
16 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
17
18 unsigned long __initdata e820_table_start;
19 unsigned long __meminitdata e820_table_end;
20 unsigned long __meminitdata e820_table_top;
21
22 int after_bootmem;
23
24 int direct_gbpages
25 #ifdef CONFIG_DIRECT_GBPAGES
26                                 = 1
27 #endif
28 ;
29
30 int nx_enabled;
31
32 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
33 static int disable_nx __cpuinitdata;
34
35 /*
36  * noexec = on|off
37  *
38  * Control non-executable mappings for processes.
39  *
40  * on      Enable
41  * off     Disable
42  */
43 static int __init noexec_setup(char *str)
44 {
45         if (!str)
46                 return -EINVAL;
47         if (!strncmp(str, "on", 2)) {
48                 __supported_pte_mask |= _PAGE_NX;
49                 disable_nx = 0;
50         } else if (!strncmp(str, "off", 3)) {
51                 disable_nx = 1;
52                 __supported_pte_mask &= ~_PAGE_NX;
53         }
54         return 0;
55 }
56 early_param("noexec", noexec_setup);
57 #endif
58
59 #ifdef CONFIG_X86_PAE
60 static void __init set_nx(void)
61 {
62         unsigned int v[4], l, h;
63
64         if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
65                 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
66
67                 if ((v[3] & (1 << 20)) && !disable_nx) {
68                         rdmsr(MSR_EFER, l, h);
69                         l |= EFER_NX;
70                         wrmsr(MSR_EFER, l, h);
71                         nx_enabled = 1;
72                         __supported_pte_mask |= _PAGE_NX;
73                 }
74         }
75 }
76 #else
77 static inline void set_nx(void)
78 {
79 }
80 #endif
81
82 #ifdef CONFIG_X86_64
83 void __cpuinit check_efer(void)
84 {
85         unsigned long efer;
86
87         rdmsrl(MSR_EFER, efer);
88         if (!(efer & EFER_NX) || disable_nx)
89                 __supported_pte_mask &= ~_PAGE_NX;
90 }
91 #endif
92
93 static void __init find_early_table_space(unsigned long end, int use_pse,
94                                           int use_gbpages)
95 {
96         unsigned long puds, pmds, ptes, tables, start;
97
98         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
99         tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
100
101         if (use_gbpages) {
102                 unsigned long extra;
103
104                 extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
105                 pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
106         } else
107                 pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
108
109         tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
110
111         if (use_pse) {
112                 unsigned long extra;
113
114                 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
115 #ifdef CONFIG_X86_32
116                 extra += PMD_SIZE;
117 #endif
118                 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
119         } else
120                 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
121
122         tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
123
124 #ifdef CONFIG_X86_32
125         /* for fixmap */
126         tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
127 #endif
128
129         /*
130          * RED-PEN putting page tables only on node 0 could
131          * cause a hotspot and fill up ZONE_DMA. The page tables
132          * need roughly 0.5KB per GB.
133          */
134 #ifdef CONFIG_X86_32
135         start = 0x7000;
136 #else
137         start = 0x8000;
138 #endif
139         e820_table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
140                                         tables, PAGE_SIZE);
141         if (e820_table_start == -1UL)
142                 panic("Cannot find space for the kernel page tables");
143
144         e820_table_start >>= PAGE_SHIFT;
145         e820_table_end = e820_table_start;
146         e820_table_top = e820_table_start + (tables >> PAGE_SHIFT);
147
148         printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
149                 end, e820_table_start << PAGE_SHIFT, e820_table_top << PAGE_SHIFT);
150 }
151
152 struct map_range {
153         unsigned long start;
154         unsigned long end;
155         unsigned page_size_mask;
156 };
157
158 #ifdef CONFIG_X86_32
159 #define NR_RANGE_MR 3
160 #else /* CONFIG_X86_64 */
161 #define NR_RANGE_MR 5
162 #endif
163
164 static int __meminit save_mr(struct map_range *mr, int nr_range,
165                              unsigned long start_pfn, unsigned long end_pfn,
166                              unsigned long page_size_mask)
167 {
168         if (start_pfn < end_pfn) {
169                 if (nr_range >= NR_RANGE_MR)
170                         panic("run out of range for init_memory_mapping\n");
171                 mr[nr_range].start = start_pfn<<PAGE_SHIFT;
172                 mr[nr_range].end   = end_pfn<<PAGE_SHIFT;
173                 mr[nr_range].page_size_mask = page_size_mask;
174                 nr_range++;
175         }
176
177         return nr_range;
178 }
179
180 #ifdef CONFIG_X86_64
181 static void __init init_gbpages(void)
182 {
183         if (direct_gbpages && cpu_has_gbpages)
184                 printk(KERN_INFO "Using GB pages for direct mapping\n");
185         else
186                 direct_gbpages = 0;
187 }
188 #else
189 static inline void init_gbpages(void)
190 {
191 }
192 #endif
193
194 /*
195  * Setup the direct mapping of the physical memory at PAGE_OFFSET.
196  * This runs before bootmem is initialized and gets pages directly from
197  * the physical memory. To access them they are temporarily mapped.
198  */
199 unsigned long __init_refok init_memory_mapping(unsigned long start,
200                                                unsigned long end)
201 {
202         unsigned long page_size_mask = 0;
203         unsigned long start_pfn, end_pfn;
204         unsigned long ret = 0;
205         unsigned long pos;
206
207         struct map_range mr[NR_RANGE_MR];
208         int nr_range, i;
209         int use_pse, use_gbpages;
210
211         printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end);
212
213         if (!after_bootmem)
214                 init_gbpages();
215
216 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
217         /*
218          * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
219          * This will simplify cpa(), which otherwise needs to support splitting
220          * large pages into small in interrupt context, etc.
221          */
222         use_pse = use_gbpages = 0;
223 #else
224         use_pse = cpu_has_pse;
225         use_gbpages = direct_gbpages;
226 #endif
227
228         set_nx();
229         if (nx_enabled)
230                 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
231
232         /* Enable PSE if available */
233         if (cpu_has_pse)
234                 set_in_cr4(X86_CR4_PSE);
235
236         /* Enable PGE if available */
237         if (cpu_has_pge) {
238                 set_in_cr4(X86_CR4_PGE);
239                 __supported_pte_mask |= _PAGE_GLOBAL;
240         }
241
242         if (use_gbpages)
243                 page_size_mask |= 1 << PG_LEVEL_1G;
244         if (use_pse)
245                 page_size_mask |= 1 << PG_LEVEL_2M;
246
247         memset(mr, 0, sizeof(mr));
248         nr_range = 0;
249
250         /* head if not big page alignment ? */
251         start_pfn = start >> PAGE_SHIFT;
252         pos = start_pfn << PAGE_SHIFT;
253 #ifdef CONFIG_X86_32
254         /*
255          * Don't use a large page for the first 2/4MB of memory
256          * because there are often fixed size MTRRs in there
257          * and overlapping MTRRs into large pages can cause
258          * slowdowns.
259          */
260         if (pos == 0)
261                 end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
262         else
263                 end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
264                                  << (PMD_SHIFT - PAGE_SHIFT);
265 #else /* CONFIG_X86_64 */
266         end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)
267                         << (PMD_SHIFT - PAGE_SHIFT);
268 #endif
269         if (end_pfn > (end >> PAGE_SHIFT))
270                 end_pfn = end >> PAGE_SHIFT;
271         if (start_pfn < end_pfn) {
272                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
273                 pos = end_pfn << PAGE_SHIFT;
274         }
275
276         /* big page (2M) range */
277         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
278                          << (PMD_SHIFT - PAGE_SHIFT);
279 #ifdef CONFIG_X86_32
280         end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
281 #else /* CONFIG_X86_64 */
282         end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
283                          << (PUD_SHIFT - PAGE_SHIFT);
284         if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)))
285                 end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT));
286 #endif
287
288         if (start_pfn < end_pfn) {
289                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
290                                 page_size_mask & (1<<PG_LEVEL_2M));
291                 pos = end_pfn << PAGE_SHIFT;
292         }
293
294 #ifdef CONFIG_X86_64
295         /* big page (1G) range */
296         start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
297                          << (PUD_SHIFT - PAGE_SHIFT);
298         end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
299         if (start_pfn < end_pfn) {
300                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
301                                 page_size_mask &
302                                  ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
303                 pos = end_pfn << PAGE_SHIFT;
304         }
305
306         /* tail is not big page (1G) alignment */
307         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
308                          << (PMD_SHIFT - PAGE_SHIFT);
309         end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
310         if (start_pfn < end_pfn) {
311                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
312                                 page_size_mask & (1<<PG_LEVEL_2M));
313                 pos = end_pfn << PAGE_SHIFT;
314         }
315 #endif
316
317         /* tail is not big page (2M) alignment */
318         start_pfn = pos>>PAGE_SHIFT;
319         end_pfn = end>>PAGE_SHIFT;
320         nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
321
322         /* try to merge same page size and continuous */
323         for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
324                 unsigned long old_start;
325                 if (mr[i].end != mr[i+1].start ||
326                     mr[i].page_size_mask != mr[i+1].page_size_mask)
327                         continue;
328                 /* move it */
329                 old_start = mr[i].start;
330                 memmove(&mr[i], &mr[i+1],
331                         (nr_range - 1 - i) * sizeof(struct map_range));
332                 mr[i--].start = old_start;
333                 nr_range--;
334         }
335
336         for (i = 0; i < nr_range; i++)
337                 printk(KERN_DEBUG " %010lx - %010lx page %s\n",
338                                 mr[i].start, mr[i].end,
339                         (mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
340                          (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
341
342         /*
343          * Find space for the kernel direct mapping tables.
344          *
345          * Later we should allocate these tables in the local node of the
346          * memory mapped. Unfortunately this is done currently before the
347          * nodes are discovered.
348          */
349         if (!after_bootmem)
350                 find_early_table_space(end, use_pse, use_gbpages);
351
352 #ifdef CONFIG_X86_32
353         for (i = 0; i < nr_range; i++)
354                 kernel_physical_mapping_init(mr[i].start, mr[i].end,
355                                              mr[i].page_size_mask);
356         ret = end;
357 #else /* CONFIG_X86_64 */
358         for (i = 0; i < nr_range; i++)
359                 ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
360                                                    mr[i].page_size_mask);
361 #endif
362
363 #ifdef CONFIG_X86_32
364         early_ioremap_page_table_range_init();
365
366         load_cr3(swapper_pg_dir);
367 #endif
368
369 #ifdef CONFIG_X86_64
370         if (!after_bootmem && !start) {
371                 pud_t *pud;
372                 pmd_t *pmd;
373
374                 mmu_cr4_features = read_cr4();
375
376                 /*
377                  * _brk_end cannot change anymore, but it and _end may be
378                  * located on different 2M pages. cleanup_highmap(), however,
379                  * can only consider _end when it runs, so destroy any
380                  * mappings beyond _brk_end here.
381                  */
382                 pud = pud_offset(pgd_offset_k(_brk_end), _brk_end);
383                 pmd = pmd_offset(pud, _brk_end - 1);
384                 while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1))
385                         pmd_clear(pmd);
386         }
387 #endif
388         __flush_tlb_all();
389
390         if (!after_bootmem && e820_table_end > e820_table_start)
391                 reserve_early(e820_table_start << PAGE_SHIFT,
392                                  e820_table_end << PAGE_SHIFT, "PGTABLE");
393
394         if (!after_bootmem)
395                 early_memtest(start, end);
396
397         return ret >> PAGE_SHIFT;
398 }
399
400
401 /*
402  * devmem_is_allowed() checks to see if /dev/mem access to a certain address
403  * is valid. The argument is a physical page number.
404  *
405  *
406  * On x86, access has to be given to the first megabyte of ram because that area
407  * contains bios code and data regions used by X and dosemu and similar apps.
408  * Access has to be given to non-kernel-ram areas as well, these contain the PCI
409  * mmio resources as well as potential bios/acpi data regions.
410  */
411 int devmem_is_allowed(unsigned long pagenr)
412 {
413         if (pagenr <= 256)
414                 return 1;
415         if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
416                 return 0;
417         if (!page_is_ram(pagenr))
418                 return 1;
419         return 0;
420 }
421
422 void free_init_pages(char *what, unsigned long begin, unsigned long end)
423 {
424         unsigned long addr = begin;
425
426         if (addr >= end)
427                 return;
428
429         /*
430          * If debugging page accesses then do not free this memory but
431          * mark them not present - any buggy init-section access will
432          * create a kernel page fault:
433          */
434 #ifdef CONFIG_DEBUG_PAGEALLOC
435         printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
436                 begin, PAGE_ALIGN(end));
437         set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
438 #else
439         /*
440          * We just marked the kernel text read only above, now that
441          * we are going to free part of that, we need to make that
442          * writeable first.
443          */
444         set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
445
446         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
447
448         for (; addr < end; addr += PAGE_SIZE) {
449                 ClearPageReserved(virt_to_page(addr));
450                 init_page_count(virt_to_page(addr));
451                 memset((void *)(addr & ~(PAGE_SIZE-1)),
452                         POISON_FREE_INITMEM, PAGE_SIZE);
453                 free_page(addr);
454                 totalram_pages++;
455         }
456 #endif
457 }
458
459 void free_initmem(void)
460 {
461         free_init_pages("unused kernel memory",
462                         (unsigned long)(&__init_begin),
463                         (unsigned long)(&__init_end));
464 }
465
466 #ifdef CONFIG_BLK_DEV_INITRD
467 void free_initrd_mem(unsigned long start, unsigned long end)
468 {
469         free_init_pages("initrd memory", start, end);
470 }
471 #endif