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
34 #include <asm/asm.h>
35 #include <asm/bios_ebda.h>
36 #include <asm/processor.h>
37 #include <linux/uaccess.h>
38 #include <asm/dma.h>
39 #include <asm/fixmap.h>
40 #include <asm/e820/api.h>
41 #include <asm/apic.h>
42 #include <asm/bugs.h>
43 #include <asm/tlb.h>
44 #include <asm/tlbflush.h>
45 #include <asm/olpc_ofw.h>
46 #include <asm/pgalloc.h>
47 #include <asm/sections.h>
48 #include <asm/setup.h>
49 #include <asm/set_memory.h>
50 #include <asm/page_types.h>
51 #include <asm/cpu_entry_area.h>
52 #include <asm/init.h>
53 #include <asm/pgtable_areas.h>
54 #include <asm/numa.h>
55
56 #include "mm_internal.h"
57
58 unsigned long highstart_pfn, highend_pfn;
59
60 bool __read_mostly __vmalloc_start_set = false;
61
62 /*
63 * Creates a middle page table and puts a pointer to it in the
64 * given global directory entry. This only returns the gd entry
65 * in non-PAE compilation mode, since the middle layer is folded.
66 */
one_md_table_init(pgd_t * pgd)67 static pmd_t * __init one_md_table_init(pgd_t *pgd)
68 {
69 p4d_t *p4d;
70 pud_t *pud;
71 pmd_t *pmd_table;
72
73 #ifdef CONFIG_X86_PAE
74 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
75 pmd_table = (pmd_t *)alloc_low_page();
76 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
77 p4d = p4d_offset(pgd, 0);
78 pud = pud_offset(p4d, 0);
79 BUG_ON(pmd_table != pmd_offset(pud, 0));
80
81 return pmd_table;
82 }
83 #endif
84 p4d = p4d_offset(pgd, 0);
85 pud = pud_offset(p4d, 0);
86 pmd_table = pmd_offset(pud, 0);
87
88 return pmd_table;
89 }
90
91 /*
92 * Create a page table and place a pointer to it in a middle page
93 * directory entry:
94 */
one_page_table_init(pmd_t * pmd)95 static pte_t * __init one_page_table_init(pmd_t *pmd)
96 {
97 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
98 pte_t *page_table = (pte_t *)alloc_low_page();
99
100 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
101 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
102 }
103
104 return pte_offset_kernel(pmd, 0);
105 }
106
populate_extra_pmd(unsigned long vaddr)107 pmd_t * __init populate_extra_pmd(unsigned long vaddr)
108 {
109 int pgd_idx = pgd_index(vaddr);
110 int pmd_idx = pmd_index(vaddr);
111
112 return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx;
113 }
114
populate_extra_pte(unsigned long vaddr)115 pte_t * __init populate_extra_pte(unsigned long vaddr)
116 {
117 int pte_idx = pte_index(vaddr);
118 pmd_t *pmd;
119
120 pmd = populate_extra_pmd(vaddr);
121 return one_page_table_init(pmd) + pte_idx;
122 }
123
124 static unsigned long __init
page_table_range_init_count(unsigned long start,unsigned long end)125 page_table_range_init_count(unsigned long start, unsigned long end)
126 {
127 unsigned long count = 0;
128 #ifdef CONFIG_HIGHMEM
129 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
130 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
131 int pgd_idx, pmd_idx;
132 unsigned long vaddr;
133
134 if (pmd_idx_kmap_begin == pmd_idx_kmap_end)
135 return 0;
136
137 vaddr = start;
138 pgd_idx = pgd_index(vaddr);
139 pmd_idx = pmd_index(vaddr);
140
141 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) {
142 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
143 pmd_idx++) {
144 if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin &&
145 (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end)
146 count++;
147 vaddr += PMD_SIZE;
148 }
149 pmd_idx = 0;
150 }
151 #endif
152 return count;
153 }
154
page_table_kmap_check(pte_t * pte,pmd_t * pmd,unsigned long vaddr,pte_t * lastpte,void ** adr)155 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
156 unsigned long vaddr, pte_t *lastpte,
157 void **adr)
158 {
159 #ifdef CONFIG_HIGHMEM
160 /*
161 * Something (early fixmap) may already have put a pte
162 * page here, which causes the page table allocation
163 * to become nonlinear. Attempt to fix it, and if it
164 * is still nonlinear then we have to bug.
165 */
166 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
167 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
168
169 if (pmd_idx_kmap_begin != pmd_idx_kmap_end
170 && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
171 && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) {
172 pte_t *newpte;
173 int i;
174
175 BUG_ON(after_bootmem);
176 newpte = *adr;
177 for (i = 0; i < PTRS_PER_PTE; i++)
178 set_pte(newpte + i, pte[i]);
179 *adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE);
180
181 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
182 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
183 __flush_tlb_all();
184
185 pte = newpte;
186 }
187 BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
188 && vaddr > fix_to_virt(FIX_KMAP_END)
189 && lastpte && lastpte + PTRS_PER_PTE != pte);
190 #endif
191 return pte;
192 }
193
194 /*
195 * This function initializes a certain range of kernel virtual memory
196 * with new bootmem page tables, everywhere page tables are missing in
197 * the given range.
198 *
199 * NOTE: The pagetables are allocated contiguous on the physical space
200 * so we can cache the place of the first one and move around without
201 * checking the pgd every time.
202 */
203 static void __init
page_table_range_init(unsigned long start,unsigned long end,pgd_t * pgd_base)204 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
205 {
206 int pgd_idx, pmd_idx;
207 unsigned long vaddr;
208 pgd_t *pgd;
209 pmd_t *pmd;
210 pte_t *pte = NULL;
211 unsigned long count = page_table_range_init_count(start, end);
212 void *adr = NULL;
213
214 if (count)
215 adr = alloc_low_pages(count);
216
217 vaddr = start;
218 pgd_idx = pgd_index(vaddr);
219 pmd_idx = pmd_index(vaddr);
220 pgd = pgd_base + pgd_idx;
221
222 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
223 pmd = one_md_table_init(pgd);
224 pmd = pmd + pmd_index(vaddr);
225 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
226 pmd++, pmd_idx++) {
227 pte = page_table_kmap_check(one_page_table_init(pmd),
228 pmd, vaddr, pte, &adr);
229
230 vaddr += PMD_SIZE;
231 }
232 pmd_idx = 0;
233 }
234 }
235
is_x86_32_kernel_text(unsigned long addr)236 static inline int is_x86_32_kernel_text(unsigned long addr)
237 {
238 if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end)
239 return 1;
240 return 0;
241 }
242
243 /*
244 * This maps the physical memory to kernel virtual address space, a total
245 * of max_low_pfn pages, by creating page tables starting from address
246 * PAGE_OFFSET:
247 */
248 unsigned long __init
kernel_physical_mapping_init(unsigned long start,unsigned long end,unsigned long page_size_mask,pgprot_t prot)249 kernel_physical_mapping_init(unsigned long start,
250 unsigned long end,
251 unsigned long page_size_mask,
252 pgprot_t prot)
253 {
254 int use_pse = page_size_mask == (1<<PG_LEVEL_2M);
255 unsigned long last_map_addr = end;
256 unsigned long start_pfn, end_pfn;
257 pgd_t *pgd_base = swapper_pg_dir;
258 int pgd_idx, pmd_idx, pte_ofs;
259 unsigned long pfn;
260 pgd_t *pgd;
261 pmd_t *pmd;
262 pte_t *pte;
263 unsigned pages_2m, pages_4k;
264 int mapping_iter;
265
266 start_pfn = start >> PAGE_SHIFT;
267 end_pfn = end >> PAGE_SHIFT;
268
269 /*
270 * First iteration will setup identity mapping using large/small pages
271 * based on use_pse, with other attributes same as set by
272 * the early code in head_32.S
273 *
274 * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
275 * as desired for the kernel identity mapping.
276 *
277 * This two pass mechanism conforms to the TLB app note which says:
278 *
279 * "Software should not write to a paging-structure entry in a way
280 * that would change, for any linear address, both the page size
281 * and either the page frame or attributes."
282 */
283 mapping_iter = 1;
284
285 if (!boot_cpu_has(X86_FEATURE_PSE))
286 use_pse = 0;
287
288 repeat:
289 pages_2m = pages_4k = 0;
290 pfn = start_pfn;
291 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
292 pgd = pgd_base + pgd_idx;
293 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
294 pmd = one_md_table_init(pgd);
295
296 if (pfn >= end_pfn)
297 continue;
298 #ifdef CONFIG_X86_PAE
299 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
300 pmd += pmd_idx;
301 #else
302 pmd_idx = 0;
303 #endif
304 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
305 pmd++, pmd_idx++) {
306 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
307
308 /*
309 * Map with big pages if possible, otherwise
310 * create normal page tables:
311 */
312 if (use_pse) {
313 unsigned int addr2;
314 pgprot_t prot = PAGE_KERNEL_LARGE;
315 /*
316 * first pass will use the same initial
317 * identity mapping attribute + _PAGE_PSE.
318 */
319 pgprot_t init_prot =
320 __pgprot(PTE_IDENT_ATTR |
321 _PAGE_PSE);
322
323 pfn &= PMD_MASK >> PAGE_SHIFT;
324 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
325 PAGE_OFFSET + PAGE_SIZE-1;
326
327 if (is_x86_32_kernel_text(addr) ||
328 is_x86_32_kernel_text(addr2))
329 prot = PAGE_KERNEL_LARGE_EXEC;
330
331 pages_2m++;
332 if (mapping_iter == 1)
333 set_pmd(pmd, pfn_pmd(pfn, init_prot));
334 else
335 set_pmd(pmd, pfn_pmd(pfn, prot));
336
337 pfn += PTRS_PER_PTE;
338 continue;
339 }
340 pte = one_page_table_init(pmd);
341
342 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
343 pte += pte_ofs;
344 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
345 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
346 pgprot_t prot = PAGE_KERNEL;
347 /*
348 * first pass will use the same initial
349 * identity mapping attribute.
350 */
351 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
352
353 if (is_x86_32_kernel_text(addr))
354 prot = PAGE_KERNEL_EXEC;
355
356 pages_4k++;
357 if (mapping_iter == 1) {
358 set_pte(pte, pfn_pte(pfn, init_prot));
359 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE;
360 } else
361 set_pte(pte, pfn_pte(pfn, prot));
362 }
363 }
364 }
365 if (mapping_iter == 1) {
366 /*
367 * update direct mapping page count only in the first
368 * iteration.
369 */
370 update_page_count(PG_LEVEL_2M, pages_2m);
371 update_page_count(PG_LEVEL_4K, pages_4k);
372
373 /*
374 * local global flush tlb, which will flush the previous
375 * mappings present in both small and large page TLB's.
376 */
377 __flush_tlb_all();
378
379 /*
380 * Second iteration will set the actual desired PTE attributes.
381 */
382 mapping_iter = 2;
383 goto repeat;
384 }
385 return last_map_addr;
386 }
387
388 #ifdef CONFIG_HIGHMEM
permanent_kmaps_init(pgd_t * pgd_base)389 static void __init permanent_kmaps_init(pgd_t *pgd_base)
390 {
391 unsigned long vaddr = PKMAP_BASE;
392
393 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
394
395 pkmap_page_table = virt_to_kpte(vaddr);
396 }
397
add_highpages_with_active_regions(int nid,unsigned long start_pfn,unsigned long end_pfn)398 void __init add_highpages_with_active_regions(int nid,
399 unsigned long start_pfn, unsigned long end_pfn)
400 {
401 phys_addr_t start, end;
402 u64 i;
403
404 for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) {
405 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start),
406 start_pfn, end_pfn);
407 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end),
408 start_pfn, end_pfn);
409 for ( ; pfn < e_pfn; pfn++)
410 if (pfn_valid(pfn))
411 free_highmem_page(pfn_to_page(pfn));
412 }
413 }
414 #else
permanent_kmaps_init(pgd_t * pgd_base)415 static inline void permanent_kmaps_init(pgd_t *pgd_base)
416 {
417 }
418 #endif /* CONFIG_HIGHMEM */
419
sync_initial_page_table(void)420 void __init sync_initial_page_table(void)
421 {
422 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY,
423 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
424 KERNEL_PGD_PTRS);
425
426 /*
427 * sync back low identity map too. It is used for example
428 * in the 32-bit EFI stub.
429 */
430 clone_pgd_range(initial_page_table,
431 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
432 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
433 }
434
native_pagetable_init(void)435 void __init native_pagetable_init(void)
436 {
437 unsigned long pfn, va;
438 pgd_t *pgd, *base = swapper_pg_dir;
439 p4d_t *p4d;
440 pud_t *pud;
441 pmd_t *pmd;
442 pte_t *pte;
443
444 /*
445 * Remove any mappings which extend past the end of physical
446 * memory from the boot time page table.
447 * In virtual address space, we should have at least two pages
448 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END
449 * definition. And max_low_pfn is set to VMALLOC_END physical
450 * address. If initial memory mapping is doing right job, we
451 * should have pte used near max_low_pfn or one pmd is not present.
452 */
453 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
454 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
455 pgd = base + pgd_index(va);
456 if (!pgd_present(*pgd))
457 break;
458
459 p4d = p4d_offset(pgd, va);
460 pud = pud_offset(p4d, va);
461 pmd = pmd_offset(pud, va);
462 if (!pmd_present(*pmd))
463 break;
464
465 /* should not be large page here */
466 if (pmd_large(*pmd)) {
467 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",
468 pfn, pmd, __pa(pmd));
469 BUG_ON(1);
470 }
471
472 pte = pte_offset_kernel(pmd, va);
473 if (!pte_present(*pte))
474 break;
475
476 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n",
477 pfn, pmd, __pa(pmd), pte, __pa(pte));
478 pte_clear(NULL, va, pte);
479 }
480 paging_init();
481 }
482
483 /*
484 * Build a proper pagetable for the kernel mappings. Up until this
485 * point, we've been running on some set of pagetables constructed by
486 * the boot process.
487 *
488 * This will be a pagetable constructed in arch/x86/kernel/head_32.S.
489 * The root of the pagetable will be swapper_pg_dir.
490 *
491 * In general, pagetable_init() assumes that the pagetable may already
492 * be partially populated, and so it avoids stomping on any existing
493 * mappings.
494 */
early_ioremap_page_table_range_init(void)495 void __init early_ioremap_page_table_range_init(void)
496 {
497 pgd_t *pgd_base = swapper_pg_dir;
498 unsigned long vaddr, end;
499
500 /*
501 * Fixed mappings, only the page table structure has to be
502 * created - mappings will be set by set_fixmap():
503 */
504 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
505 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
506 page_table_range_init(vaddr, end, pgd_base);
507 early_ioremap_reset();
508 }
509
pagetable_init(void)510 static void __init pagetable_init(void)
511 {
512 pgd_t *pgd_base = swapper_pg_dir;
513
514 permanent_kmaps_init(pgd_base);
515 }
516
517 #define DEFAULT_PTE_MASK ~(_PAGE_NX | _PAGE_GLOBAL)
518 /* Bits supported by the hardware: */
519 pteval_t __supported_pte_mask __read_mostly = DEFAULT_PTE_MASK;
520 /* Bits allowed in normal kernel mappings: */
521 pteval_t __default_kernel_pte_mask __read_mostly = DEFAULT_PTE_MASK;
522 EXPORT_SYMBOL_GPL(__supported_pte_mask);
523 /* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */
524 EXPORT_SYMBOL(__default_kernel_pte_mask);
525
526 /* user-defined highmem size */
527 static unsigned int highmem_pages = -1;
528
529 /*
530 * highmem=size forces highmem to be exactly 'size' bytes.
531 * This works even on boxes that have no highmem otherwise.
532 * This also works to reduce highmem size on bigger boxes.
533 */
parse_highmem(char * arg)534 static int __init parse_highmem(char *arg)
535 {
536 if (!arg)
537 return -EINVAL;
538
539 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
540 return 0;
541 }
542 early_param("highmem", parse_highmem);
543
544 #define MSG_HIGHMEM_TOO_BIG \
545 "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
546
547 #define MSG_LOWMEM_TOO_SMALL \
548 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
549 /*
550 * All of RAM fits into lowmem - but if user wants highmem
551 * artificially via the highmem=x boot parameter then create
552 * it:
553 */
lowmem_pfn_init(void)554 static void __init lowmem_pfn_init(void)
555 {
556 /* max_low_pfn is 0, we already have early_res support */
557 max_low_pfn = max_pfn;
558
559 if (highmem_pages == -1)
560 highmem_pages = 0;
561 #ifdef CONFIG_HIGHMEM
562 if (highmem_pages >= max_pfn) {
563 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
564 pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
565 highmem_pages = 0;
566 }
567 if (highmem_pages) {
568 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
569 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
570 pages_to_mb(highmem_pages));
571 highmem_pages = 0;
572 }
573 max_low_pfn -= highmem_pages;
574 }
575 #else
576 if (highmem_pages)
577 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
578 #endif
579 }
580
581 #define MSG_HIGHMEM_TOO_SMALL \
582 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
583
584 #define MSG_HIGHMEM_TRIMMED \
585 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
586 /*
587 * We have more RAM than fits into lowmem - we try to put it into
588 * highmem, also taking the highmem=x boot parameter into account:
589 */
highmem_pfn_init(void)590 static void __init highmem_pfn_init(void)
591 {
592 max_low_pfn = MAXMEM_PFN;
593
594 if (highmem_pages == -1)
595 highmem_pages = max_pfn - MAXMEM_PFN;
596
597 if (highmem_pages + MAXMEM_PFN < max_pfn)
598 max_pfn = MAXMEM_PFN + highmem_pages;
599
600 if (highmem_pages + MAXMEM_PFN > max_pfn) {
601 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
602 pages_to_mb(max_pfn - MAXMEM_PFN),
603 pages_to_mb(highmem_pages));
604 highmem_pages = 0;
605 }
606 #ifndef CONFIG_HIGHMEM
607 /* Maximum memory usable is what is directly addressable */
608 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
609 if (max_pfn > MAX_NONPAE_PFN)
610 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
611 else
612 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
613 max_pfn = MAXMEM_PFN;
614 #else /* !CONFIG_HIGHMEM */
615 #ifndef CONFIG_HIGHMEM64G
616 if (max_pfn > MAX_NONPAE_PFN) {
617 max_pfn = MAX_NONPAE_PFN;
618 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
619 }
620 #endif /* !CONFIG_HIGHMEM64G */
621 #endif /* !CONFIG_HIGHMEM */
622 }
623
624 /*
625 * Determine low and high memory ranges:
626 */
find_low_pfn_range(void)627 void __init find_low_pfn_range(void)
628 {
629 /* it could update max_pfn */
630
631 if (max_pfn <= MAXMEM_PFN)
632 lowmem_pfn_init();
633 else
634 highmem_pfn_init();
635 }
636
637 #ifndef CONFIG_NUMA
initmem_init(void)638 void __init initmem_init(void)
639 {
640 #ifdef CONFIG_HIGHMEM
641 highstart_pfn = highend_pfn = max_pfn;
642 if (max_pfn > max_low_pfn)
643 highstart_pfn = max_low_pfn;
644 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
645 pages_to_mb(highend_pfn - highstart_pfn));
646 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
647 #else
648 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
649 #endif
650
651 memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0);
652
653 #ifdef CONFIG_FLATMEM
654 max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn;
655 #endif
656 __vmalloc_start_set = true;
657
658 printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
659 pages_to_mb(max_low_pfn));
660
661 setup_bootmem_allocator();
662 }
663 #endif /* !CONFIG_NUMA */
664
setup_bootmem_allocator(void)665 void __init setup_bootmem_allocator(void)
666 {
667 printk(KERN_INFO " mapped low ram: 0 - %08lx\n",
668 max_pfn_mapped<<PAGE_SHIFT);
669 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
670 }
671
672 /*
673 * paging_init() sets up the page tables - note that the first 8MB are
674 * already mapped by head.S.
675 *
676 * This routines also unmaps the page at virtual kernel address 0, so
677 * that we can trap those pesky NULL-reference errors in the kernel.
678 */
paging_init(void)679 void __init paging_init(void)
680 {
681 pagetable_init();
682
683 __flush_tlb_all();
684
685 /*
686 * NOTE: at this point the bootmem allocator is fully available.
687 */
688 olpc_dt_build_devicetree();
689 sparse_init();
690 zone_sizes_init();
691 }
692
693 /*
694 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
695 * and also on some strange 486's. All 586+'s are OK. This used to involve
696 * black magic jumps to work around some nasty CPU bugs, but fortunately the
697 * switch to using exceptions got rid of all that.
698 */
test_wp_bit(void)699 static void __init test_wp_bit(void)
700 {
701 char z = 0;
702
703 printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode...");
704
705 __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO);
706
707 if (copy_to_kernel_nofault((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) {
708 clear_fixmap(FIX_WP_TEST);
709 printk(KERN_CONT "Ok.\n");
710 return;
711 }
712
713 printk(KERN_CONT "No.\n");
714 panic("Linux doesn't support CPUs with broken WP.");
715 }
716
mem_init(void)717 void __init mem_init(void)
718 {
719 pci_iommu_alloc();
720
721 #ifdef CONFIG_FLATMEM
722 BUG_ON(!mem_map);
723 #endif
724 /*
725 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to
726 * be done before memblock_free_all(). Memblock use free low memory for
727 * temporary data (see find_range_array()) and for this purpose can use
728 * pages that was already passed to the buddy allocator, hence marked as
729 * not accessible in the page tables when compiled with
730 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not
731 * important here.
732 */
733 set_highmem_pages_init();
734
735 /* this will put all low memory onto the freelists */
736 memblock_free_all();
737
738 after_bootmem = 1;
739 x86_init.hyper.init_after_bootmem();
740
741 /*
742 * Check boundaries twice: Some fundamental inconsistencies can
743 * be detected at build time already.
744 */
745 #define __FIXADDR_TOP (-PAGE_SIZE)
746 #ifdef CONFIG_HIGHMEM
747 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
748 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE);
749 #endif
750 #define high_memory (-128UL << 20)
751 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END);
752 #undef high_memory
753 #undef __FIXADDR_TOP
754
755 #ifdef CONFIG_HIGHMEM
756 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
757 BUG_ON(VMALLOC_END > PKMAP_BASE);
758 #endif
759 BUG_ON(VMALLOC_START >= VMALLOC_END);
760 BUG_ON((unsigned long)high_memory > VMALLOC_START);
761
762 test_wp_bit();
763 }
764
765 int kernel_set_to_readonly __read_mostly;
766
mark_nxdata_nx(void)767 static void mark_nxdata_nx(void)
768 {
769 /*
770 * When this called, init has already been executed and released,
771 * so everything past _etext should be NX.
772 */
773 unsigned long start = PFN_ALIGN(_etext);
774 /*
775 * This comes from is_x86_32_kernel_text upper limit. Also HPAGE where used:
776 */
777 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start;
778
779 if (__supported_pte_mask & _PAGE_NX)
780 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10);
781 set_memory_nx(start, size >> PAGE_SHIFT);
782 }
783
mark_rodata_ro(void)784 void mark_rodata_ro(void)
785 {
786 unsigned long start = PFN_ALIGN(_text);
787 unsigned long size = (unsigned long)__end_rodata - start;
788
789 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
790 pr_info("Write protecting kernel text and read-only data: %luk\n",
791 size >> 10);
792
793 kernel_set_to_readonly = 1;
794
795 #ifdef CONFIG_CPA_DEBUG
796 pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size);
797 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
798
799 pr_info("Testing CPA: write protecting again\n");
800 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
801 #endif
802 mark_nxdata_nx();
803 if (__supported_pte_mask & _PAGE_NX)
804 debug_checkwx();
805 }
806