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/paravirt.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 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
78 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
79 p4d = p4d_offset(pgd, 0);
80 pud = pud_offset(p4d, 0);
81 BUG_ON(pmd_table != pmd_offset(pud, 0));
82
83 return pmd_table;
84 }
85 #endif
86 p4d = p4d_offset(pgd, 0);
87 pud = pud_offset(p4d, 0);
88 pmd_table = pmd_offset(pud, 0);
89
90 return pmd_table;
91 }
92
93 /*
94 * Create a page table and place a pointer to it in a middle page
95 * directory entry:
96 */
one_page_table_init(pmd_t * pmd)97 static pte_t * __init one_page_table_init(pmd_t *pmd)
98 {
99 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
100 pte_t *page_table = (pte_t *)alloc_low_page();
101
102 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
103 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
104 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
105 }
106
107 return pte_offset_kernel(pmd, 0);
108 }
109
populate_extra_pmd(unsigned long vaddr)110 pmd_t * __init populate_extra_pmd(unsigned long vaddr)
111 {
112 int pgd_idx = pgd_index(vaddr);
113 int pmd_idx = pmd_index(vaddr);
114
115 return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx;
116 }
117
populate_extra_pte(unsigned long vaddr)118 pte_t * __init populate_extra_pte(unsigned long vaddr)
119 {
120 int pte_idx = pte_index(vaddr);
121 pmd_t *pmd;
122
123 pmd = populate_extra_pmd(vaddr);
124 return one_page_table_init(pmd) + pte_idx;
125 }
126
127 static unsigned long __init
page_table_range_init_count(unsigned long start,unsigned long end)128 page_table_range_init_count(unsigned long start, unsigned long end)
129 {
130 unsigned long count = 0;
131 #ifdef CONFIG_HIGHMEM
132 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
133 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
134 int pgd_idx, pmd_idx;
135 unsigned long vaddr;
136
137 if (pmd_idx_kmap_begin == pmd_idx_kmap_end)
138 return 0;
139
140 vaddr = start;
141 pgd_idx = pgd_index(vaddr);
142 pmd_idx = pmd_index(vaddr);
143
144 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) {
145 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
146 pmd_idx++) {
147 if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin &&
148 (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end)
149 count++;
150 vaddr += PMD_SIZE;
151 }
152 pmd_idx = 0;
153 }
154 #endif
155 return count;
156 }
157
page_table_kmap_check(pte_t * pte,pmd_t * pmd,unsigned long vaddr,pte_t * lastpte,void ** adr)158 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
159 unsigned long vaddr, pte_t *lastpte,
160 void **adr)
161 {
162 #ifdef CONFIG_HIGHMEM
163 /*
164 * Something (early fixmap) may already have put a pte
165 * page here, which causes the page table allocation
166 * to become nonlinear. Attempt to fix it, and if it
167 * is still nonlinear then we have to bug.
168 */
169 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
170 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
171
172 if (pmd_idx_kmap_begin != pmd_idx_kmap_end
173 && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
174 && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) {
175 pte_t *newpte;
176 int i;
177
178 BUG_ON(after_bootmem);
179 newpte = *adr;
180 for (i = 0; i < PTRS_PER_PTE; i++)
181 set_pte(newpte + i, pte[i]);
182 *adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE);
183
184 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
185 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
186 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
187 __flush_tlb_all();
188
189 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
190 pte = newpte;
191 }
192 BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
193 && vaddr > fix_to_virt(FIX_KMAP_END)
194 && lastpte && lastpte + PTRS_PER_PTE != pte);
195 #endif
196 return pte;
197 }
198
199 /*
200 * This function initializes a certain range of kernel virtual memory
201 * with new bootmem page tables, everywhere page tables are missing in
202 * the given range.
203 *
204 * NOTE: The pagetables are allocated contiguous on the physical space
205 * so we can cache the place of the first one and move around without
206 * checking the pgd every time.
207 */
208 static void __init
page_table_range_init(unsigned long start,unsigned long end,pgd_t * pgd_base)209 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
210 {
211 int pgd_idx, pmd_idx;
212 unsigned long vaddr;
213 pgd_t *pgd;
214 pmd_t *pmd;
215 pte_t *pte = NULL;
216 unsigned long count = page_table_range_init_count(start, end);
217 void *adr = NULL;
218
219 if (count)
220 adr = alloc_low_pages(count);
221
222 vaddr = start;
223 pgd_idx = pgd_index(vaddr);
224 pmd_idx = pmd_index(vaddr);
225 pgd = pgd_base + pgd_idx;
226
227 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
228 pmd = one_md_table_init(pgd);
229 pmd = pmd + pmd_index(vaddr);
230 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
231 pmd++, pmd_idx++) {
232 pte = page_table_kmap_check(one_page_table_init(pmd),
233 pmd, vaddr, pte, &adr);
234
235 vaddr += PMD_SIZE;
236 }
237 pmd_idx = 0;
238 }
239 }
240
is_x86_32_kernel_text(unsigned long addr)241 static inline int is_x86_32_kernel_text(unsigned long addr)
242 {
243 if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end)
244 return 1;
245 return 0;
246 }
247
248 /*
249 * This maps the physical memory to kernel virtual address space, a total
250 * of max_low_pfn pages, by creating page tables starting from address
251 * PAGE_OFFSET:
252 */
253 unsigned long __init
kernel_physical_mapping_init(unsigned long start,unsigned long end,unsigned long page_size_mask,pgprot_t prot)254 kernel_physical_mapping_init(unsigned long start,
255 unsigned long end,
256 unsigned long page_size_mask,
257 pgprot_t prot)
258 {
259 int use_pse = page_size_mask == (1<<PG_LEVEL_2M);
260 unsigned long last_map_addr = end;
261 unsigned long start_pfn, end_pfn;
262 pgd_t *pgd_base = swapper_pg_dir;
263 int pgd_idx, pmd_idx, pte_ofs;
264 unsigned long pfn;
265 pgd_t *pgd;
266 pmd_t *pmd;
267 pte_t *pte;
268 unsigned pages_2m, pages_4k;
269 int mapping_iter;
270
271 start_pfn = start >> PAGE_SHIFT;
272 end_pfn = end >> PAGE_SHIFT;
273
274 /*
275 * First iteration will setup identity mapping using large/small pages
276 * based on use_pse, with other attributes same as set by
277 * the early code in head_32.S
278 *
279 * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
280 * as desired for the kernel identity mapping.
281 *
282 * This two pass mechanism conforms to the TLB app note which says:
283 *
284 * "Software should not write to a paging-structure entry in a way
285 * that would change, for any linear address, both the page size
286 * and either the page frame or attributes."
287 */
288 mapping_iter = 1;
289
290 if (!boot_cpu_has(X86_FEATURE_PSE))
291 use_pse = 0;
292
293 repeat:
294 pages_2m = pages_4k = 0;
295 pfn = start_pfn;
296 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
297 pgd = pgd_base + pgd_idx;
298 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
299 pmd = one_md_table_init(pgd);
300
301 if (pfn >= end_pfn)
302 continue;
303 #ifdef CONFIG_X86_PAE
304 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
305 pmd += pmd_idx;
306 #else
307 pmd_idx = 0;
308 #endif
309 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
310 pmd++, pmd_idx++) {
311 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
312
313 /*
314 * Map with big pages if possible, otherwise
315 * create normal page tables:
316 */
317 if (use_pse) {
318 unsigned int addr2;
319 pgprot_t prot = PAGE_KERNEL_LARGE;
320 /*
321 * first pass will use the same initial
322 * identity mapping attribute + _PAGE_PSE.
323 */
324 pgprot_t init_prot =
325 __pgprot(PTE_IDENT_ATTR |
326 _PAGE_PSE);
327
328 pfn &= PMD_MASK >> PAGE_SHIFT;
329 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
330 PAGE_OFFSET + PAGE_SIZE-1;
331
332 if (is_x86_32_kernel_text(addr) ||
333 is_x86_32_kernel_text(addr2))
334 prot = PAGE_KERNEL_LARGE_EXEC;
335
336 pages_2m++;
337 if (mapping_iter == 1)
338 set_pmd(pmd, pfn_pmd(pfn, init_prot));
339 else
340 set_pmd(pmd, pfn_pmd(pfn, prot));
341
342 pfn += PTRS_PER_PTE;
343 continue;
344 }
345 pte = one_page_table_init(pmd);
346
347 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
348 pte += pte_ofs;
349 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
350 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
351 pgprot_t prot = PAGE_KERNEL;
352 /*
353 * first pass will use the same initial
354 * identity mapping attribute.
355 */
356 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
357
358 if (is_x86_32_kernel_text(addr))
359 prot = PAGE_KERNEL_EXEC;
360
361 pages_4k++;
362 if (mapping_iter == 1) {
363 set_pte(pte, pfn_pte(pfn, init_prot));
364 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE;
365 } else
366 set_pte(pte, pfn_pte(pfn, prot));
367 }
368 }
369 }
370 if (mapping_iter == 1) {
371 /*
372 * update direct mapping page count only in the first
373 * iteration.
374 */
375 update_page_count(PG_LEVEL_2M, pages_2m);
376 update_page_count(PG_LEVEL_4K, pages_4k);
377
378 /*
379 * local global flush tlb, which will flush the previous
380 * mappings present in both small and large page TLB's.
381 */
382 __flush_tlb_all();
383
384 /*
385 * Second iteration will set the actual desired PTE attributes.
386 */
387 mapping_iter = 2;
388 goto repeat;
389 }
390 return last_map_addr;
391 }
392
393 #ifdef CONFIG_HIGHMEM
permanent_kmaps_init(pgd_t * pgd_base)394 static void __init permanent_kmaps_init(pgd_t *pgd_base)
395 {
396 unsigned long vaddr = PKMAP_BASE;
397
398 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
399
400 pkmap_page_table = virt_to_kpte(vaddr);
401 }
402
add_highpages_with_active_regions(int nid,unsigned long start_pfn,unsigned long end_pfn)403 void __init add_highpages_with_active_regions(int nid,
404 unsigned long start_pfn, unsigned long end_pfn)
405 {
406 phys_addr_t start, end;
407 u64 i;
408
409 for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) {
410 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start),
411 start_pfn, end_pfn);
412 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end),
413 start_pfn, end_pfn);
414 for ( ; pfn < e_pfn; pfn++)
415 if (pfn_valid(pfn))
416 free_highmem_page(pfn_to_page(pfn));
417 }
418 }
419 #else
permanent_kmaps_init(pgd_t * pgd_base)420 static inline void permanent_kmaps_init(pgd_t *pgd_base)
421 {
422 }
423 #endif /* CONFIG_HIGHMEM */
424
sync_initial_page_table(void)425 void __init sync_initial_page_table(void)
426 {
427 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY,
428 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
429 KERNEL_PGD_PTRS);
430
431 /*
432 * sync back low identity map too. It is used for example
433 * in the 32-bit EFI stub.
434 */
435 clone_pgd_range(initial_page_table,
436 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
437 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
438 }
439
native_pagetable_init(void)440 void __init native_pagetable_init(void)
441 {
442 unsigned long pfn, va;
443 pgd_t *pgd, *base = swapper_pg_dir;
444 p4d_t *p4d;
445 pud_t *pud;
446 pmd_t *pmd;
447 pte_t *pte;
448
449 /*
450 * Remove any mappings which extend past the end of physical
451 * memory from the boot time page table.
452 * In virtual address space, we should have at least two pages
453 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END
454 * definition. And max_low_pfn is set to VMALLOC_END physical
455 * address. If initial memory mapping is doing right job, we
456 * should have pte used near max_low_pfn or one pmd is not present.
457 */
458 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
459 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
460 pgd = base + pgd_index(va);
461 if (!pgd_present(*pgd))
462 break;
463
464 p4d = p4d_offset(pgd, va);
465 pud = pud_offset(p4d, va);
466 pmd = pmd_offset(pud, va);
467 if (!pmd_present(*pmd))
468 break;
469
470 /* should not be large page here */
471 if (pmd_large(*pmd)) {
472 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",
473 pfn, pmd, __pa(pmd));
474 BUG_ON(1);
475 }
476
477 pte = pte_offset_kernel(pmd, va);
478 if (!pte_present(*pte))
479 break;
480
481 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n",
482 pfn, pmd, __pa(pmd), pte, __pa(pte));
483 pte_clear(NULL, va, pte);
484 }
485 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
486 paging_init();
487 }
488
489 /*
490 * Build a proper pagetable for the kernel mappings. Up until this
491 * point, we've been running on some set of pagetables constructed by
492 * the boot process.
493 *
494 * If we're booting on native hardware, this will be a pagetable
495 * constructed in arch/x86/kernel/head_32.S. The root of the
496 * pagetable will be swapper_pg_dir.
497 *
498 * If we're booting paravirtualized under a hypervisor, then there are
499 * more options: we may already be running PAE, and the pagetable may
500 * or may not be based in swapper_pg_dir. In any case,
501 * paravirt_pagetable_init() will set up swapper_pg_dir
502 * appropriately for the rest of the initialization to work.
503 *
504 * In general, pagetable_init() assumes that the pagetable may already
505 * be partially populated, and so it avoids stomping on any existing
506 * mappings.
507 */
early_ioremap_page_table_range_init(void)508 void __init early_ioremap_page_table_range_init(void)
509 {
510 pgd_t *pgd_base = swapper_pg_dir;
511 unsigned long vaddr, end;
512
513 /*
514 * Fixed mappings, only the page table structure has to be
515 * created - mappings will be set by set_fixmap():
516 */
517 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
518 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
519 page_table_range_init(vaddr, end, pgd_base);
520 early_ioremap_reset();
521 }
522
pagetable_init(void)523 static void __init pagetable_init(void)
524 {
525 pgd_t *pgd_base = swapper_pg_dir;
526
527 permanent_kmaps_init(pgd_base);
528 }
529
530 #define DEFAULT_PTE_MASK ~(_PAGE_NX | _PAGE_GLOBAL)
531 /* Bits supported by the hardware: */
532 pteval_t __supported_pte_mask __read_mostly = DEFAULT_PTE_MASK;
533 /* Bits allowed in normal kernel mappings: */
534 pteval_t __default_kernel_pte_mask __read_mostly = DEFAULT_PTE_MASK;
535 EXPORT_SYMBOL_GPL(__supported_pte_mask);
536 /* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */
537 EXPORT_SYMBOL(__default_kernel_pte_mask);
538
539 /* user-defined highmem size */
540 static unsigned int highmem_pages = -1;
541
542 /*
543 * highmem=size forces highmem to be exactly 'size' bytes.
544 * This works even on boxes that have no highmem otherwise.
545 * This also works to reduce highmem size on bigger boxes.
546 */
parse_highmem(char * arg)547 static int __init parse_highmem(char *arg)
548 {
549 if (!arg)
550 return -EINVAL;
551
552 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
553 return 0;
554 }
555 early_param("highmem", parse_highmem);
556
557 #define MSG_HIGHMEM_TOO_BIG \
558 "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
559
560 #define MSG_LOWMEM_TOO_SMALL \
561 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
562 /*
563 * All of RAM fits into lowmem - but if user wants highmem
564 * artificially via the highmem=x boot parameter then create
565 * it:
566 */
lowmem_pfn_init(void)567 static void __init lowmem_pfn_init(void)
568 {
569 /* max_low_pfn is 0, we already have early_res support */
570 max_low_pfn = max_pfn;
571
572 if (highmem_pages == -1)
573 highmem_pages = 0;
574 #ifdef CONFIG_HIGHMEM
575 if (highmem_pages >= max_pfn) {
576 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
577 pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
578 highmem_pages = 0;
579 }
580 if (highmem_pages) {
581 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
582 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
583 pages_to_mb(highmem_pages));
584 highmem_pages = 0;
585 }
586 max_low_pfn -= highmem_pages;
587 }
588 #else
589 if (highmem_pages)
590 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
591 #endif
592 }
593
594 #define MSG_HIGHMEM_TOO_SMALL \
595 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
596
597 #define MSG_HIGHMEM_TRIMMED \
598 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
599 /*
600 * We have more RAM than fits into lowmem - we try to put it into
601 * highmem, also taking the highmem=x boot parameter into account:
602 */
highmem_pfn_init(void)603 static void __init highmem_pfn_init(void)
604 {
605 max_low_pfn = MAXMEM_PFN;
606
607 if (highmem_pages == -1)
608 highmem_pages = max_pfn - MAXMEM_PFN;
609
610 if (highmem_pages + MAXMEM_PFN < max_pfn)
611 max_pfn = MAXMEM_PFN + highmem_pages;
612
613 if (highmem_pages + MAXMEM_PFN > max_pfn) {
614 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
615 pages_to_mb(max_pfn - MAXMEM_PFN),
616 pages_to_mb(highmem_pages));
617 highmem_pages = 0;
618 }
619 #ifndef CONFIG_HIGHMEM
620 /* Maximum memory usable is what is directly addressable */
621 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
622 if (max_pfn > MAX_NONPAE_PFN)
623 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
624 else
625 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
626 max_pfn = MAXMEM_PFN;
627 #else /* !CONFIG_HIGHMEM */
628 #ifndef CONFIG_HIGHMEM64G
629 if (max_pfn > MAX_NONPAE_PFN) {
630 max_pfn = MAX_NONPAE_PFN;
631 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
632 }
633 #endif /* !CONFIG_HIGHMEM64G */
634 #endif /* !CONFIG_HIGHMEM */
635 }
636
637 /*
638 * Determine low and high memory ranges:
639 */
find_low_pfn_range(void)640 void __init find_low_pfn_range(void)
641 {
642 /* it could update max_pfn */
643
644 if (max_pfn <= MAXMEM_PFN)
645 lowmem_pfn_init();
646 else
647 highmem_pfn_init();
648 }
649
650 #ifndef CONFIG_NUMA
initmem_init(void)651 void __init initmem_init(void)
652 {
653 #ifdef CONFIG_HIGHMEM
654 highstart_pfn = highend_pfn = max_pfn;
655 if (max_pfn > max_low_pfn)
656 highstart_pfn = max_low_pfn;
657 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
658 pages_to_mb(highend_pfn - highstart_pfn));
659 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
660 #else
661 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
662 #endif
663
664 memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0);
665
666 #ifdef CONFIG_FLATMEM
667 max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn;
668 #endif
669 __vmalloc_start_set = true;
670
671 printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
672 pages_to_mb(max_low_pfn));
673
674 setup_bootmem_allocator();
675 }
676 #endif /* !CONFIG_NUMA */
677
setup_bootmem_allocator(void)678 void __init setup_bootmem_allocator(void)
679 {
680 printk(KERN_INFO " mapped low ram: 0 - %08lx\n",
681 max_pfn_mapped<<PAGE_SHIFT);
682 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
683 }
684
685 /*
686 * paging_init() sets up the page tables - note that the first 8MB are
687 * already mapped by head.S.
688 *
689 * This routines also unmaps the page at virtual kernel address 0, so
690 * that we can trap those pesky NULL-reference errors in the kernel.
691 */
paging_init(void)692 void __init paging_init(void)
693 {
694 pagetable_init();
695
696 __flush_tlb_all();
697
698 /*
699 * NOTE: at this point the bootmem allocator is fully available.
700 */
701 olpc_dt_build_devicetree();
702 sparse_init();
703 zone_sizes_init();
704 }
705
706 /*
707 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
708 * and also on some strange 486's. All 586+'s are OK. This used to involve
709 * black magic jumps to work around some nasty CPU bugs, but fortunately the
710 * switch to using exceptions got rid of all that.
711 */
test_wp_bit(void)712 static void __init test_wp_bit(void)
713 {
714 char z = 0;
715
716 printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode...");
717
718 __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO);
719
720 if (copy_to_kernel_nofault((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) {
721 clear_fixmap(FIX_WP_TEST);
722 printk(KERN_CONT "Ok.\n");
723 return;
724 }
725
726 printk(KERN_CONT "No.\n");
727 panic("Linux doesn't support CPUs with broken WP.");
728 }
729
mem_init(void)730 void __init mem_init(void)
731 {
732 pci_iommu_alloc();
733
734 #ifdef CONFIG_FLATMEM
735 BUG_ON(!mem_map);
736 #endif
737 /*
738 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to
739 * be done before memblock_free_all(). Memblock use free low memory for
740 * temporary data (see find_range_array()) and for this purpose can use
741 * pages that was already passed to the buddy allocator, hence marked as
742 * not accessible in the page tables when compiled with
743 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not
744 * important here.
745 */
746 set_highmem_pages_init();
747
748 /* this will put all low memory onto the freelists */
749 memblock_free_all();
750
751 after_bootmem = 1;
752 x86_init.hyper.init_after_bootmem();
753
754 /*
755 * Check boundaries twice: Some fundamental inconsistencies can
756 * be detected at build time already.
757 */
758 #define __FIXADDR_TOP (-PAGE_SIZE)
759 #ifdef CONFIG_HIGHMEM
760 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
761 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE);
762 #endif
763 #define high_memory (-128UL << 20)
764 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END);
765 #undef high_memory
766 #undef __FIXADDR_TOP
767
768 #ifdef CONFIG_HIGHMEM
769 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
770 BUG_ON(VMALLOC_END > PKMAP_BASE);
771 #endif
772 BUG_ON(VMALLOC_START >= VMALLOC_END);
773 BUG_ON((unsigned long)high_memory > VMALLOC_START);
774
775 test_wp_bit();
776 }
777
778 int kernel_set_to_readonly __read_mostly;
779
mark_nxdata_nx(void)780 static void mark_nxdata_nx(void)
781 {
782 /*
783 * When this called, init has already been executed and released,
784 * so everything past _etext should be NX.
785 */
786 unsigned long start = PFN_ALIGN(_etext);
787 /*
788 * This comes from is_x86_32_kernel_text upper limit. Also HPAGE where used:
789 */
790 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start;
791
792 if (__supported_pte_mask & _PAGE_NX)
793 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10);
794 set_memory_nx(start, size >> PAGE_SHIFT);
795 }
796
mark_rodata_ro(void)797 void mark_rodata_ro(void)
798 {
799 unsigned long start = PFN_ALIGN(_text);
800 unsigned long size = (unsigned long)__end_rodata - start;
801
802 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
803 pr_info("Write protecting kernel text and read-only data: %luk\n",
804 size >> 10);
805
806 kernel_set_to_readonly = 1;
807
808 #ifdef CONFIG_CPA_DEBUG
809 pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size);
810 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
811
812 pr_info("Testing CPA: write protecting again\n");
813 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
814 #endif
815 mark_nxdata_nx();
816 if (__supported_pte_mask & _PAGE_NX)
817 debug_checkwx();
818 }
819