1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 *
4 * Copyright (C) 1995 Linus Torvalds
5 *
6 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
7 */
8
9 #include <linux/signal.h>
10 #include <linux/sched.h>
11 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/string.h>
14 #include <linux/types.h>
15 #include <linux/ptrace.h>
16 #include <linux/mman.h>
17 #include <linux/mm.h>
18 #include <linux/hugetlb.h>
19 #include <linux/swap.h>
20 #include <linux/smp.h>
21 #include <linux/init.h>
22 #include <linux/highmem.h>
23 #include <linux/pagemap.h>
24 #include <linux/pci.h>
25 #include <linux/pfn.h>
26 #include <linux/poison.h>
27 #include <linux/memblock.h>
28 #include <linux/proc_fs.h>
29 #include <linux/memory_hotplug.h>
30 #include <linux/initrd.h>
31 #include <linux/cpumask.h>
32 #include <linux/gfp.h>
33 #include <linux/execmem.h>
34
35 #include <asm/asm.h>
36 #include <asm/bios_ebda.h>
37 #include <asm/processor.h>
38 #include <linux/uaccess.h>
39 #include <asm/dma.h>
40 #include <asm/fixmap.h>
41 #include <asm/e820/api.h>
42 #include <asm/apic.h>
43 #include <asm/bugs.h>
44 #include <asm/tlb.h>
45 #include <asm/tlbflush.h>
46 #include <asm/olpc_ofw.h>
47 #include <asm/pgalloc.h>
48 #include <asm/sections.h>
49 #include <asm/setup.h>
50 #include <asm/set_memory.h>
51 #include <asm/page_types.h>
52 #include <asm/cpu_entry_area.h>
53 #include <asm/init.h>
54 #include <asm/pgtable_areas.h>
55 #include <asm/numa.h>
56
57 #include "mm_internal.h"
58
59 unsigned long highstart_pfn, highend_pfn;
60
61 bool __read_mostly __vmalloc_start_set = false;
62
63 /*
64 * Creates a middle page table and puts a pointer to it in the
65 * given global directory entry. This only returns the gd entry
66 * in non-PAE compilation mode, since the middle layer is folded.
67 */
one_md_table_init(pgd_t * pgd)68 static pmd_t * __init one_md_table_init(pgd_t *pgd)
69 {
70 p4d_t *p4d;
71 pud_t *pud;
72 pmd_t *pmd_table;
73
74 #ifdef CONFIG_X86_PAE
75 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
76 pmd_table = (pmd_t *)alloc_low_page();
77 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
78 p4d = p4d_offset(pgd, 0);
79 pud = pud_offset(p4d, 0);
80 BUG_ON(pmd_table != pmd_offset(pud, 0));
81
82 return pmd_table;
83 }
84 #endif
85 p4d = p4d_offset(pgd, 0);
86 pud = pud_offset(p4d, 0);
87 pmd_table = pmd_offset(pud, 0);
88
89 return pmd_table;
90 }
91
92 /*
93 * Create a page table and place a pointer to it in a middle page
94 * directory entry:
95 */
one_page_table_init(pmd_t * pmd)96 static pte_t * __init one_page_table_init(pmd_t *pmd)
97 {
98 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
99 pte_t *page_table = (pte_t *)alloc_low_page();
100
101 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
102 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
103 }
104
105 return pte_offset_kernel(pmd, 0);
106 }
107
populate_extra_pmd(unsigned long vaddr)108 pmd_t * __init populate_extra_pmd(unsigned long vaddr)
109 {
110 int pgd_idx = pgd_index(vaddr);
111 int pmd_idx = pmd_index(vaddr);
112
113 return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx;
114 }
115
populate_extra_pte(unsigned long vaddr)116 pte_t * __init populate_extra_pte(unsigned long vaddr)
117 {
118 int pte_idx = pte_index(vaddr);
119 pmd_t *pmd;
120
121 pmd = populate_extra_pmd(vaddr);
122 return one_page_table_init(pmd) + pte_idx;
123 }
124
125 static unsigned long __init
page_table_range_init_count(unsigned long start,unsigned long end)126 page_table_range_init_count(unsigned long start, unsigned long end)
127 {
128 unsigned long count = 0;
129 #ifdef CONFIG_HIGHMEM
130 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
131 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
132 int pgd_idx, pmd_idx;
133 unsigned long vaddr;
134
135 if (pmd_idx_kmap_begin == pmd_idx_kmap_end)
136 return 0;
137
138 vaddr = start;
139 pgd_idx = pgd_index(vaddr);
140 pmd_idx = pmd_index(vaddr);
141
142 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) {
143 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
144 pmd_idx++) {
145 if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin &&
146 (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end)
147 count++;
148 vaddr += PMD_SIZE;
149 }
150 pmd_idx = 0;
151 }
152 #endif
153 return count;
154 }
155
page_table_kmap_check(pte_t * pte,pmd_t * pmd,unsigned long vaddr,pte_t * lastpte,void ** adr)156 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
157 unsigned long vaddr, pte_t *lastpte,
158 void **adr)
159 {
160 #ifdef CONFIG_HIGHMEM
161 /*
162 * Something (early fixmap) may already have put a pte
163 * page here, which causes the page table allocation
164 * to become nonlinear. Attempt to fix it, and if it
165 * is still nonlinear then we have to bug.
166 */
167 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
168 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
169
170 if (pmd_idx_kmap_begin != pmd_idx_kmap_end
171 && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
172 && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) {
173 pte_t *newpte;
174 int i;
175
176 BUG_ON(after_bootmem);
177 newpte = *adr;
178 for (i = 0; i < PTRS_PER_PTE; i++)
179 set_pte(newpte + i, pte[i]);
180 *adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE);
181
182 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
183 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
184 __flush_tlb_all();
185
186 pte = newpte;
187 }
188 BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
189 && vaddr > fix_to_virt(FIX_KMAP_END)
190 && lastpte && lastpte + PTRS_PER_PTE != pte);
191 #endif
192 return pte;
193 }
194
195 /*
196 * This function initializes a certain range of kernel virtual memory
197 * with new bootmem page tables, everywhere page tables are missing in
198 * the given range.
199 *
200 * NOTE: The pagetables are allocated contiguous on the physical space
201 * so we can cache the place of the first one and move around without
202 * checking the pgd every time.
203 */
204 static void __init
page_table_range_init(unsigned long start,unsigned long end,pgd_t * pgd_base)205 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
206 {
207 int pgd_idx, pmd_idx;
208 unsigned long vaddr;
209 pgd_t *pgd;
210 pmd_t *pmd;
211 pte_t *pte = NULL;
212 unsigned long count = page_table_range_init_count(start, end);
213 void *adr = NULL;
214
215 if (count)
216 adr = alloc_low_pages(count);
217
218 vaddr = start;
219 pgd_idx = pgd_index(vaddr);
220 pmd_idx = pmd_index(vaddr);
221 pgd = pgd_base + pgd_idx;
222
223 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
224 pmd = one_md_table_init(pgd);
225 pmd = pmd + pmd_index(vaddr);
226 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
227 pmd++, pmd_idx++) {
228 pte = page_table_kmap_check(one_page_table_init(pmd),
229 pmd, vaddr, pte, &adr);
230
231 vaddr += PMD_SIZE;
232 }
233 pmd_idx = 0;
234 }
235 }
236
is_x86_32_kernel_text(unsigned long addr)237 static inline int is_x86_32_kernel_text(unsigned long addr)
238 {
239 if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end)
240 return 1;
241 return 0;
242 }
243
244 /*
245 * This maps the physical memory to kernel virtual address space, a total
246 * of max_low_pfn pages, by creating page tables starting from address
247 * PAGE_OFFSET:
248 */
249 unsigned long __init
kernel_physical_mapping_init(unsigned long start,unsigned long end,unsigned long page_size_mask,pgprot_t prot)250 kernel_physical_mapping_init(unsigned long start,
251 unsigned long end,
252 unsigned long page_size_mask,
253 pgprot_t prot)
254 {
255 int use_pse = page_size_mask == (1<<PG_LEVEL_2M);
256 unsigned long last_map_addr = end;
257 unsigned long start_pfn, end_pfn;
258 pgd_t *pgd_base = swapper_pg_dir;
259 int pgd_idx, pmd_idx, pte_ofs;
260 unsigned long pfn;
261 pgd_t *pgd;
262 pmd_t *pmd;
263 pte_t *pte;
264 unsigned pages_2m, pages_4k;
265 int mapping_iter;
266
267 start_pfn = start >> PAGE_SHIFT;
268 end_pfn = end >> PAGE_SHIFT;
269
270 /*
271 * First iteration will setup identity mapping using large/small pages
272 * based on use_pse, with other attributes same as set by
273 * the early code in head_32.S
274 *
275 * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
276 * as desired for the kernel identity mapping.
277 *
278 * This two pass mechanism conforms to the TLB app note which says:
279 *
280 * "Software should not write to a paging-structure entry in a way
281 * that would change, for any linear address, both the page size
282 * and either the page frame or attributes."
283 */
284 mapping_iter = 1;
285
286 if (!boot_cpu_has(X86_FEATURE_PSE))
287 use_pse = 0;
288
289 repeat:
290 pages_2m = pages_4k = 0;
291 pfn = start_pfn;
292 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
293 pgd = pgd_base + pgd_idx;
294 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
295 pmd = one_md_table_init(pgd);
296
297 if (pfn >= end_pfn)
298 continue;
299 #ifdef CONFIG_X86_PAE
300 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
301 pmd += pmd_idx;
302 #else
303 pmd_idx = 0;
304 #endif
305 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
306 pmd++, pmd_idx++) {
307 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
308
309 /*
310 * Map with big pages if possible, otherwise
311 * create normal page tables:
312 */
313 if (use_pse) {
314 unsigned int addr2;
315 pgprot_t prot = PAGE_KERNEL_LARGE;
316 /*
317 * first pass will use the same initial
318 * identity mapping attribute + _PAGE_PSE.
319 */
320 pgprot_t init_prot =
321 __pgprot(PTE_IDENT_ATTR |
322 _PAGE_PSE);
323
324 pfn &= PMD_MASK >> PAGE_SHIFT;
325 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
326 PAGE_OFFSET + PAGE_SIZE-1;
327
328 if (is_x86_32_kernel_text(addr) ||
329 is_x86_32_kernel_text(addr2))
330 prot = PAGE_KERNEL_LARGE_EXEC;
331
332 pages_2m++;
333 if (mapping_iter == 1)
334 set_pmd(pmd, pfn_pmd(pfn, init_prot));
335 else
336 set_pmd(pmd, pfn_pmd(pfn, prot));
337
338 pfn += PTRS_PER_PTE;
339 continue;
340 }
341 pte = one_page_table_init(pmd);
342
343 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
344 pte += pte_ofs;
345 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
346 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
347 pgprot_t prot = PAGE_KERNEL;
348 /*
349 * first pass will use the same initial
350 * identity mapping attribute.
351 */
352 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
353
354 if (is_x86_32_kernel_text(addr))
355 prot = PAGE_KERNEL_EXEC;
356
357 pages_4k++;
358 if (mapping_iter == 1) {
359 set_pte(pte, pfn_pte(pfn, init_prot));
360 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE;
361 } else
362 set_pte(pte, pfn_pte(pfn, prot));
363 }
364 }
365 }
366 if (mapping_iter == 1) {
367 /*
368 * update direct mapping page count only in the first
369 * iteration.
370 */
371 update_page_count(PG_LEVEL_2M, pages_2m);
372 update_page_count(PG_LEVEL_4K, pages_4k);
373
374 /*
375 * local global flush tlb, which will flush the previous
376 * mappings present in both small and large page TLB's.
377 */
378 __flush_tlb_all();
379
380 /*
381 * Second iteration will set the actual desired PTE attributes.
382 */
383 mapping_iter = 2;
384 goto repeat;
385 }
386 return last_map_addr;
387 }
388
389 #ifdef CONFIG_HIGHMEM
permanent_kmaps_init(pgd_t * pgd_base)390 static void __init permanent_kmaps_init(pgd_t *pgd_base)
391 {
392 unsigned long vaddr = PKMAP_BASE;
393
394 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
395
396 pkmap_page_table = virt_to_kpte(vaddr);
397 }
398 #else
permanent_kmaps_init(pgd_t * pgd_base)399 static inline void permanent_kmaps_init(pgd_t *pgd_base)
400 {
401 }
402 #endif /* CONFIG_HIGHMEM */
403
sync_initial_page_table(void)404 void __init sync_initial_page_table(void)
405 {
406 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY,
407 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
408 KERNEL_PGD_PTRS);
409
410 /*
411 * sync back low identity map too. It is used for example
412 * in the 32-bit EFI stub.
413 */
414 clone_pgd_range(initial_page_table,
415 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
416 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
417 }
418
native_pagetable_init(void)419 void __init native_pagetable_init(void)
420 {
421 unsigned long pfn, va;
422 pgd_t *pgd, *base = swapper_pg_dir;
423 p4d_t *p4d;
424 pud_t *pud;
425 pmd_t *pmd;
426 pte_t *pte;
427
428 /*
429 * Remove any mappings which extend past the end of physical
430 * memory from the boot time page table.
431 * In virtual address space, we should have at least two pages
432 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END
433 * definition. And max_low_pfn is set to VMALLOC_END physical
434 * address. If initial memory mapping is doing right job, we
435 * should have pte used near max_low_pfn or one pmd is not present.
436 */
437 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
438 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
439 pgd = base + pgd_index(va);
440 if (!pgd_present(*pgd))
441 break;
442
443 p4d = p4d_offset(pgd, va);
444 pud = pud_offset(p4d, va);
445 pmd = pmd_offset(pud, va);
446 if (!pmd_present(*pmd))
447 break;
448
449 /* should not be large page here */
450 if (pmd_leaf(*pmd)) {
451 pr_warn("try to clear pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx, but pmd is big page and is not using pte !\n",
452 pfn, pmd, __pa(pmd));
453 BUG_ON(1);
454 }
455
456 pte = pte_offset_kernel(pmd, va);
457 if (!pte_present(*pte))
458 break;
459
460 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n",
461 pfn, pmd, __pa(pmd), pte, __pa(pte));
462 pte_clear(NULL, va, pte);
463 }
464 paging_init();
465 }
466
467 /*
468 * Build a proper pagetable for the kernel mappings. Up until this
469 * point, we've been running on some set of pagetables constructed by
470 * the boot process.
471 *
472 * This will be a pagetable constructed in arch/x86/kernel/head_32.S.
473 * The root of the pagetable will be swapper_pg_dir.
474 *
475 * In general, pagetable_init() assumes that the pagetable may already
476 * be partially populated, and so it avoids stomping on any existing
477 * mappings.
478 */
early_ioremap_page_table_range_init(void)479 void __init early_ioremap_page_table_range_init(void)
480 {
481 pgd_t *pgd_base = swapper_pg_dir;
482 unsigned long vaddr, end;
483
484 /*
485 * Fixed mappings, only the page table structure has to be
486 * created - mappings will be set by set_fixmap():
487 */
488 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
489 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
490 page_table_range_init(vaddr, end, pgd_base);
491 early_ioremap_reset();
492 }
493
pagetable_init(void)494 static void __init pagetable_init(void)
495 {
496 pgd_t *pgd_base = swapper_pg_dir;
497
498 permanent_kmaps_init(pgd_base);
499 }
500
501 #define DEFAULT_PTE_MASK ~(_PAGE_NX | _PAGE_GLOBAL)
502 /* Bits supported by the hardware: */
503 pteval_t __supported_pte_mask __read_mostly = DEFAULT_PTE_MASK;
504 /* Bits allowed in normal kernel mappings: */
505 pteval_t __default_kernel_pte_mask __read_mostly = DEFAULT_PTE_MASK;
506 EXPORT_SYMBOL_GPL(__supported_pte_mask);
507 /* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */
508 EXPORT_SYMBOL(__default_kernel_pte_mask);
509
510 /* user-defined highmem size */
511 static unsigned int highmem_pages = -1;
512
513 /*
514 * highmem=size forces highmem to be exactly 'size' bytes.
515 * This works even on boxes that have no highmem otherwise.
516 * This also works to reduce highmem size on bigger boxes.
517 */
parse_highmem(char * arg)518 static int __init parse_highmem(char *arg)
519 {
520 if (!arg)
521 return -EINVAL;
522
523 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
524 return 0;
525 }
526 early_param("highmem", parse_highmem);
527
528 #define MSG_HIGHMEM_TOO_BIG \
529 "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
530
531 #define MSG_LOWMEM_TOO_SMALL \
532 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
533 /*
534 * All of RAM fits into lowmem - but if user wants highmem
535 * artificially via the highmem=x boot parameter then create
536 * it:
537 */
lowmem_pfn_init(void)538 static void __init lowmem_pfn_init(void)
539 {
540 /* max_low_pfn is 0, we already have early_res support */
541 max_low_pfn = max_pfn;
542
543 if (highmem_pages == -1)
544 highmem_pages = 0;
545 #ifdef CONFIG_HIGHMEM
546 if (highmem_pages >= max_pfn) {
547 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
548 pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
549 highmem_pages = 0;
550 }
551 if (highmem_pages) {
552 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
553 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
554 pages_to_mb(highmem_pages));
555 highmem_pages = 0;
556 }
557 max_low_pfn -= highmem_pages;
558 }
559 #else
560 if (highmem_pages)
561 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
562 #endif
563 }
564
565 #define MSG_HIGHMEM_TOO_SMALL \
566 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
567
568 #define MSG_HIGHMEM_TRIMMED \
569 "Warning: only 4GB will be used. Support for CONFIG_HIGHMEM64G was removed!\n"
570 /*
571 * We have more RAM than fits into lowmem - we try to put it into
572 * highmem, also taking the highmem=x boot parameter into account:
573 */
highmem_pfn_init(void)574 static void __init highmem_pfn_init(void)
575 {
576 max_low_pfn = MAXMEM_PFN;
577
578 if (highmem_pages == -1)
579 highmem_pages = max_pfn - MAXMEM_PFN;
580
581 if (highmem_pages + MAXMEM_PFN < max_pfn)
582 max_pfn = MAXMEM_PFN + highmem_pages;
583
584 if (highmem_pages + MAXMEM_PFN > max_pfn) {
585 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
586 pages_to_mb(max_pfn - MAXMEM_PFN),
587 pages_to_mb(highmem_pages));
588 highmem_pages = 0;
589 }
590 #ifndef CONFIG_HIGHMEM
591 /* Maximum memory usable is what is directly addressable */
592 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
593 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
594 max_pfn = MAXMEM_PFN;
595 #else /* !CONFIG_HIGHMEM */
596 if (max_pfn > MAX_NONPAE_PFN) {
597 max_pfn = MAX_NONPAE_PFN;
598 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
599 }
600 #endif /* !CONFIG_HIGHMEM */
601 }
602
603 /*
604 * Determine low and high memory ranges:
605 */
find_low_pfn_range(void)606 void __init find_low_pfn_range(void)
607 {
608 /* it could update max_pfn */
609
610 if (max_pfn <= MAXMEM_PFN)
611 lowmem_pfn_init();
612 else
613 highmem_pfn_init();
614 }
615
616 #ifndef CONFIG_NUMA
initmem_init(void)617 void __init initmem_init(void)
618 {
619 #ifdef CONFIG_HIGHMEM
620 highstart_pfn = highend_pfn = max_pfn;
621 if (max_pfn > max_low_pfn)
622 highstart_pfn = max_low_pfn;
623 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
624 pages_to_mb(highend_pfn - highstart_pfn));
625 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
626 #else
627 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
628 #endif
629
630 memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0);
631
632 __vmalloc_start_set = true;
633
634 printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
635 pages_to_mb(max_low_pfn));
636
637 setup_bootmem_allocator();
638 }
639 #endif /* !CONFIG_NUMA */
640
setup_bootmem_allocator(void)641 void __init setup_bootmem_allocator(void)
642 {
643 printk(KERN_INFO " mapped low ram: 0 - %08lx\n",
644 max_pfn_mapped<<PAGE_SHIFT);
645 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
646 }
647
648 /*
649 * paging_init() sets up the page tables - note that the first 8MB are
650 * already mapped by head.S.
651 *
652 * This routines also unmaps the page at virtual kernel address 0, so
653 * that we can trap those pesky NULL-reference errors in the kernel.
654 */
paging_init(void)655 void __init paging_init(void)
656 {
657 pagetable_init();
658
659 __flush_tlb_all();
660
661 /*
662 * NOTE: at this point the bootmem allocator is fully available.
663 */
664 olpc_dt_build_devicetree();
665 sparse_init();
666 zone_sizes_init();
667 }
668
669 /*
670 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
671 * and also on some strange 486's. All 586+'s are OK. This used to involve
672 * black magic jumps to work around some nasty CPU bugs, but fortunately the
673 * switch to using exceptions got rid of all that.
674 */
test_wp_bit(void)675 static void __init test_wp_bit(void)
676 {
677 char z = 0;
678
679 printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode...");
680
681 __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO);
682
683 if (copy_to_kernel_nofault((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) {
684 clear_fixmap(FIX_WP_TEST);
685 printk(KERN_CONT "Ok.\n");
686 return;
687 }
688
689 printk(KERN_CONT "No.\n");
690 panic("Linux doesn't support CPUs with broken WP.");
691 }
692
arch_mm_preinit(void)693 void __init arch_mm_preinit(void)
694 {
695 pci_iommu_alloc();
696
697 #ifdef CONFIG_FLATMEM
698 BUG_ON(!mem_map);
699 #endif
700 }
701
mem_init(void)702 void __init mem_init(void)
703 {
704 after_bootmem = 1;
705 x86_init.hyper.init_after_bootmem();
706
707 /*
708 * Check boundaries twice: Some fundamental inconsistencies can
709 * be detected at build time already.
710 */
711 #define __FIXADDR_TOP (-PAGE_SIZE)
712 #ifdef CONFIG_HIGHMEM
713 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
714 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE);
715 #endif
716 #define high_memory (-128UL << 20)
717 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END);
718 #undef high_memory
719 #undef __FIXADDR_TOP
720
721 #ifdef CONFIG_HIGHMEM
722 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
723 BUG_ON(VMALLOC_END > PKMAP_BASE);
724 #endif
725 BUG_ON(VMALLOC_START >= VMALLOC_END);
726 BUG_ON((unsigned long)high_memory > VMALLOC_START);
727
728 test_wp_bit();
729 }
730
731 int kernel_set_to_readonly __read_mostly;
732
mark_nxdata_nx(void)733 static void mark_nxdata_nx(void)
734 {
735 /*
736 * When this called, init has already been executed and released,
737 * so everything past _etext should be NX.
738 */
739 unsigned long start = PFN_ALIGN(_etext);
740 /*
741 * This comes from is_x86_32_kernel_text upper limit. Also HPAGE where used:
742 */
743 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start;
744
745 if (__supported_pte_mask & _PAGE_NX)
746 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10);
747 set_memory_nx(start, size >> PAGE_SHIFT);
748 }
749
mark_rodata_ro(void)750 void mark_rodata_ro(void)
751 {
752 unsigned long start = PFN_ALIGN(_text);
753 unsigned long size = (unsigned long)__end_rodata - start;
754
755 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
756 pr_info("Write protecting kernel text and read-only data: %luk\n",
757 size >> 10);
758
759 execmem_cache_make_ro();
760
761 kernel_set_to_readonly = 1;
762
763 #ifdef CONFIG_CPA_DEBUG
764 pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size);
765 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
766
767 pr_info("Testing CPA: write protecting again\n");
768 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
769 #endif
770 mark_nxdata_nx();
771 }
772