Branch data Line data Source code
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/swapfile.h>
7 : : #include <linux/swapops.h>
8 : : #include <linux/kmemleak.h>
9 : : #include <linux/sched/task.h>
10 : :
11 : : #include <asm/set_memory.h>
12 : : #include <asm/e820/api.h>
13 : : #include <asm/init.h>
14 : : #include <asm/page.h>
15 : : #include <asm/page_types.h>
16 : : #include <asm/sections.h>
17 : : #include <asm/setup.h>
18 : : #include <asm/tlbflush.h>
19 : : #include <asm/tlb.h>
20 : : #include <asm/proto.h>
21 : : #include <asm/dma.h> /* for MAX_DMA_PFN */
22 : : #include <asm/microcode.h>
23 : : #include <asm/kaslr.h>
24 : : #include <asm/hypervisor.h>
25 : : #include <asm/cpufeature.h>
26 : : #include <asm/pti.h>
27 : : #include <asm/text-patching.h>
28 : :
29 : : /*
30 : : * We need to define the tracepoints somewhere, and tlb.c
31 : : * is only compied when SMP=y.
32 : : */
33 : : #define CREATE_TRACE_POINTS
34 : : #include <trace/events/tlb.h>
35 : :
36 : : #include "mm_internal.h"
37 : :
38 : : /*
39 : : * Tables translating between page_cache_type_t and pte encoding.
40 : : *
41 : : * The default values are defined statically as minimal supported mode;
42 : : * WC and WT fall back to UC-. pat_init() updates these values to support
43 : : * more cache modes, WC and WT, when it is safe to do so. See pat_init()
44 : : * for the details. Note, __early_ioremap() used during early boot-time
45 : : * takes pgprot_t (pte encoding) and does not use these tables.
46 : : *
47 : : * Index into __cachemode2pte_tbl[] is the cachemode.
48 : : *
49 : : * Index into __pte2cachemode_tbl[] are the caching attribute bits of the pte
50 : : * (_PAGE_PWT, _PAGE_PCD, _PAGE_PAT) at index bit positions 0, 1, 2.
51 : : */
52 : : uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM] = {
53 : : [_PAGE_CACHE_MODE_WB ] = 0 | 0 ,
54 : : [_PAGE_CACHE_MODE_WC ] = 0 | _PAGE_PCD,
55 : : [_PAGE_CACHE_MODE_UC_MINUS] = 0 | _PAGE_PCD,
56 : : [_PAGE_CACHE_MODE_UC ] = _PAGE_PWT | _PAGE_PCD,
57 : : [_PAGE_CACHE_MODE_WT ] = 0 | _PAGE_PCD,
58 : : [_PAGE_CACHE_MODE_WP ] = 0 | _PAGE_PCD,
59 : : };
60 : : EXPORT_SYMBOL(__cachemode2pte_tbl);
61 : :
62 : : uint8_t __pte2cachemode_tbl[8] = {
63 : : [__pte2cm_idx( 0 | 0 | 0 )] = _PAGE_CACHE_MODE_WB,
64 : : [__pte2cm_idx(_PAGE_PWT | 0 | 0 )] = _PAGE_CACHE_MODE_UC_MINUS,
65 : : [__pte2cm_idx( 0 | _PAGE_PCD | 0 )] = _PAGE_CACHE_MODE_UC_MINUS,
66 : : [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | 0 )] = _PAGE_CACHE_MODE_UC,
67 : : [__pte2cm_idx( 0 | 0 | _PAGE_PAT)] = _PAGE_CACHE_MODE_WB,
68 : : [__pte2cm_idx(_PAGE_PWT | 0 | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
69 : : [__pte2cm_idx(0 | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
70 : : [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC,
71 : : };
72 : : EXPORT_SYMBOL(__pte2cachemode_tbl);
73 : :
74 : : static unsigned long __initdata pgt_buf_start;
75 : : static unsigned long __initdata pgt_buf_end;
76 : : static unsigned long __initdata pgt_buf_top;
77 : :
78 : : static unsigned long min_pfn_mapped;
79 : :
80 : : static bool __initdata can_use_brk_pgt = true;
81 : :
82 : : /*
83 : : * Pages returned are already directly mapped.
84 : : *
85 : : * Changing that is likely to break Xen, see commit:
86 : : *
87 : : * 279b706 x86,xen: introduce x86_init.mapping.pagetable_reserve
88 : : *
89 : : * for detailed information.
90 : : */
91 : 84 : __ref void *alloc_low_pages(unsigned int num)
92 : : {
93 : 84 : unsigned long pfn;
94 : 84 : int i;
95 : :
96 [ - + ]: 84 : if (after_bootmem) {
97 : 0 : unsigned int order;
98 : :
99 : 0 : order = get_order((unsigned long)num << PAGE_SHIFT);
100 : 0 : return (void *)__get_free_pages(GFP_ATOMIC | __GFP_ZERO, order);
101 : : }
102 : :
103 [ + - - + ]: 84 : if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) {
104 : 0 : unsigned long ret = 0;
105 : :
106 [ # # ]: 0 : if (min_pfn_mapped < max_pfn_mapped) {
107 : 0 : ret = memblock_find_in_range(
108 : 0 : min_pfn_mapped << PAGE_SHIFT,
109 : 0 : max_pfn_mapped << PAGE_SHIFT,
110 : 0 : PAGE_SIZE * num , PAGE_SIZE);
111 : : }
112 [ # # ]: 0 : if (ret)
113 : 0 : memblock_reserve(ret, PAGE_SIZE * num);
114 [ # # ]: 0 : else if (can_use_brk_pgt)
115 [ # # ]: 0 : ret = __pa(extend_brk(PAGE_SIZE * num, PAGE_SIZE));
116 : :
117 [ # # ]: 0 : if (!ret)
118 : 0 : panic("alloc_low_pages: can not alloc memory");
119 : :
120 : 0 : pfn = ret >> PAGE_SHIFT;
121 : : } else {
122 : 84 : pfn = pgt_buf_end;
123 : 84 : pgt_buf_end += num;
124 : 84 : printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
125 : 84 : pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
126 : : }
127 : :
128 [ + + ]: 168 : for (i = 0; i < num; i++) {
129 : 84 : void *adr;
130 : :
131 : 84 : adr = __va((pfn + i) << PAGE_SHIFT);
132 : 84 : clear_page(adr);
133 : : }
134 : :
135 : 84 : return __va(pfn << PAGE_SHIFT);
136 : : }
137 : :
138 : : /*
139 : : * By default need 3 4k for initial PMD_SIZE, 3 4k for 0-ISA_END_ADDRESS.
140 : : * With KASLR memory randomization, depending on the machine e820 memory
141 : : * and the PUD alignment. We may need twice more pages when KASLR memory
142 : : * randomization is enabled.
143 : : */
144 : : #ifndef CONFIG_RANDOMIZE_MEMORY
145 : : #define INIT_PGD_PAGE_COUNT 6
146 : : #else
147 : : #define INIT_PGD_PAGE_COUNT 12
148 : : #endif
149 : : #define INIT_PGT_BUF_SIZE (INIT_PGD_PAGE_COUNT * PAGE_SIZE)
150 : 0 : RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE);
151 : 21 : void __init early_alloc_pgt_buf(void)
152 : : {
153 : 21 : unsigned long tables = INIT_PGT_BUF_SIZE;
154 : 21 : phys_addr_t base;
155 : :
156 [ - + ]: 21 : base = __pa(extend_brk(tables, PAGE_SIZE));
157 : :
158 : 21 : pgt_buf_start = base >> PAGE_SHIFT;
159 : 21 : pgt_buf_end = pgt_buf_start;
160 : 21 : pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);
161 : 21 : }
162 : :
163 : : int after_bootmem;
164 : :
165 : 0 : early_param_on_off("gbpages", "nogbpages", direct_gbpages, CONFIG_X86_DIRECT_GBPAGES);
166 : :
167 : : struct map_range {
168 : : unsigned long start;
169 : : unsigned long end;
170 : : unsigned page_size_mask;
171 : : };
172 : :
173 : : static int page_size_mask;
174 : :
175 : 21 : static void __init probe_page_size_mask(void)
176 : : {
177 : : /*
178 : : * For pagealloc debugging, identity mapping will use small pages.
179 : : * This will simplify cpa(), which otherwise needs to support splitting
180 : : * large pages into small in interrupt context, etc.
181 : : */
182 [ + - ]: 21 : if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled())
183 : 21 : page_size_mask |= 1 << PG_LEVEL_2M;
184 : : else
185 : 0 : direct_gbpages = 0;
186 : :
187 : : /* Enable PSE if available */
188 [ + - ]: 21 : if (boot_cpu_has(X86_FEATURE_PSE))
189 [ - + ]: 21 : cr4_set_bits_and_update_boot(X86_CR4_PSE);
190 : :
191 : : /* Enable PGE if available */
192 : 21 : __supported_pte_mask &= ~_PAGE_GLOBAL;
193 [ + - ]: 21 : if (boot_cpu_has(X86_FEATURE_PGE)) {
194 [ - + ]: 21 : cr4_set_bits_and_update_boot(X86_CR4_PGE);
195 : 21 : __supported_pte_mask |= _PAGE_GLOBAL;
196 : : }
197 : :
198 : : /* By the default is everything supported: */
199 : 21 : __default_kernel_pte_mask = __supported_pte_mask;
200 : : /* Except when with PTI where the kernel is mostly non-Global: */
201 [ - - + ]: 21 : if (cpu_feature_enabled(X86_FEATURE_PTI))
202 : 0 : __default_kernel_pte_mask &= ~_PAGE_GLOBAL;
203 : :
204 : : /* Enable 1 GB linear kernel mappings if available: */
205 [ + - - + ]: 42 : if (direct_gbpages && boot_cpu_has(X86_FEATURE_GBPAGES)) {
206 : 0 : printk(KERN_INFO "Using GB pages for direct mapping\n");
207 : 0 : page_size_mask |= 1 << PG_LEVEL_1G;
208 : : } else {
209 : 21 : direct_gbpages = 0;
210 : : }
211 : 21 : }
212 : :
213 : 21 : static void setup_pcid(void)
214 : : {
215 : 21 : if (!IS_ENABLED(CONFIG_X86_64))
216 : : return;
217 : :
218 [ - + ]: 21 : if (!boot_cpu_has(X86_FEATURE_PCID))
219 : : return;
220 : :
221 [ # # ]: 0 : if (boot_cpu_has(X86_FEATURE_PGE)) {
222 : : /*
223 : : * This can't be cr4_set_bits_and_update_boot() -- the
224 : : * trampoline code can't handle CR4.PCIDE and it wouldn't
225 : : * do any good anyway. Despite the name,
226 : : * cr4_set_bits_and_update_boot() doesn't actually cause
227 : : * the bits in question to remain set all the way through
228 : : * the secondary boot asm.
229 : : *
230 : : * Instead, we brute-force it and set CR4.PCIDE manually in
231 : : * start_secondary().
232 : : */
233 : 0 : cr4_set_bits(X86_CR4_PCIDE);
234 : :
235 : : /*
236 : : * INVPCID's single-context modes (2/3) only work if we set
237 : : * X86_CR4_PCIDE, *and* we INVPCID support. It's unusable
238 : : * on systems that have X86_CR4_PCIDE clear, or that have
239 : : * no INVPCID support at all.
240 : : */
241 [ # # ]: 0 : if (boot_cpu_has(X86_FEATURE_INVPCID))
242 : 0 : setup_force_cpu_cap(X86_FEATURE_INVPCID_SINGLE);
243 : : } else {
244 : : /*
245 : : * flush_tlb_all(), as currently implemented, won't work if
246 : : * PCID is on but PGE is not. Since that combination
247 : : * doesn't exist on real hardware, there's no reason to try
248 : : * to fully support it, but it's polite to avoid corrupting
249 : : * data if we're on an improperly configured VM.
250 : : */
251 : 0 : setup_clear_cpu_cap(X86_FEATURE_PCID);
252 : : }
253 : : }
254 : :
255 : : #ifdef CONFIG_X86_32
256 : : #define NR_RANGE_MR 3
257 : : #else /* CONFIG_X86_64 */
258 : : #define NR_RANGE_MR 5
259 : : #endif
260 : :
261 : 189 : static int __meminit save_mr(struct map_range *mr, int nr_range,
262 : : unsigned long start_pfn, unsigned long end_pfn,
263 : : unsigned long page_size_mask)
264 : : {
265 [ + + ]: 189 : if (start_pfn < end_pfn) {
266 [ - + ]: 126 : if (nr_range >= NR_RANGE_MR)
267 : 0 : panic("run out of range for init_memory_mapping\n");
268 : 126 : mr[nr_range].start = start_pfn<<PAGE_SHIFT;
269 : 126 : mr[nr_range].end = end_pfn<<PAGE_SHIFT;
270 : 126 : mr[nr_range].page_size_mask = page_size_mask;
271 : 126 : nr_range++;
272 : : }
273 : :
274 : 189 : return nr_range;
275 : : }
276 : :
277 : : /*
278 : : * adjust the page_size_mask for small range to go with
279 : : * big page size instead small one if nearby are ram too.
280 : : */
281 : 105 : static void __ref adjust_range_page_size_mask(struct map_range *mr,
282 : : int nr_range)
283 : : {
284 : 105 : int i;
285 : :
286 [ + + ]: 231 : for (i = 0; i < nr_range; i++) {
287 [ + - ]: 126 : if ((page_size_mask & (1<<PG_LEVEL_2M)) &&
288 [ + + ]: 126 : !(mr[i].page_size_mask & (1<<PG_LEVEL_2M))) {
289 : 63 : unsigned long start = round_down(mr[i].start, PMD_SIZE);
290 : 63 : unsigned long end = round_up(mr[i].end, PMD_SIZE);
291 : :
292 : : #ifdef CONFIG_X86_32
293 : : if ((end >> PAGE_SHIFT) > max_low_pfn)
294 : : continue;
295 : : #endif
296 : :
297 [ - + ]: 63 : if (memblock_is_region_memory(start, end - start))
298 : 0 : mr[i].page_size_mask |= 1<<PG_LEVEL_2M;
299 : : }
300 [ - + ]: 126 : if ((page_size_mask & (1<<PG_LEVEL_1G)) &&
301 [ # # ]: 0 : !(mr[i].page_size_mask & (1<<PG_LEVEL_1G))) {
302 : 0 : unsigned long start = round_down(mr[i].start, PUD_SIZE);
303 : 0 : unsigned long end = round_up(mr[i].end, PUD_SIZE);
304 : :
305 [ # # ]: 0 : if (memblock_is_region_memory(start, end - start))
306 : 0 : mr[i].page_size_mask |= 1<<PG_LEVEL_1G;
307 : : }
308 : : }
309 : 105 : }
310 : :
311 : : static const char *page_size_string(struct map_range *mr)
312 : : {
313 : : static const char str_1g[] = "1G";
314 : : static const char str_2m[] = "2M";
315 : : static const char str_4m[] = "4M";
316 : : static const char str_4k[] = "4k";
317 : :
318 : : if (mr->page_size_mask & (1<<PG_LEVEL_1G))
319 : : return str_1g;
320 : : /*
321 : : * 32-bit without PAE has a 4M large page size.
322 : : * PG_LEVEL_2M is misnamed, but we can at least
323 : : * print out the right size in the string.
324 : : */
325 : : if (IS_ENABLED(CONFIG_X86_32) &&
326 : : !IS_ENABLED(CONFIG_X86_PAE) &&
327 : : mr->page_size_mask & (1<<PG_LEVEL_2M))
328 : : return str_4m;
329 : :
330 : : if (mr->page_size_mask & (1<<PG_LEVEL_2M))
331 : : return str_2m;
332 : :
333 : : return str_4k;
334 : : }
335 : :
336 : 105 : static int __meminit split_mem_range(struct map_range *mr, int nr_range,
337 : : unsigned long start,
338 : : unsigned long end)
339 : : {
340 : 105 : unsigned long start_pfn, end_pfn, limit_pfn;
341 : 105 : unsigned long pfn;
342 : 105 : int i;
343 : :
344 : 105 : limit_pfn = PFN_DOWN(end);
345 : :
346 : : /* head if not big page alignment ? */
347 : 105 : pfn = start_pfn = PFN_DOWN(start);
348 : : #ifdef CONFIG_X86_32
349 : : /*
350 : : * Don't use a large page for the first 2/4MB of memory
351 : : * because there are often fixed size MTRRs in there
352 : : * and overlapping MTRRs into large pages can cause
353 : : * slowdowns.
354 : : */
355 : : if (pfn == 0)
356 : : end_pfn = PFN_DOWN(PMD_SIZE);
357 : : else
358 : : end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
359 : : #else /* CONFIG_X86_64 */
360 : 105 : end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
361 : : #endif
362 : 105 : if (end_pfn > limit_pfn)
363 : : end_pfn = limit_pfn;
364 [ + + ]: 105 : if (start_pfn < end_pfn) {
365 : 21 : nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
366 : 21 : pfn = end_pfn;
367 : : }
368 : :
369 : : /* big page (2M) range */
370 : 105 : start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
371 : : #ifdef CONFIG_X86_32
372 : : end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
373 : : #else /* CONFIG_X86_64 */
374 : 105 : end_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
375 : 105 : if (end_pfn > round_down(limit_pfn, PFN_DOWN(PMD_SIZE)))
376 : : end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
377 : : #endif
378 : :
379 [ + + ]: 105 : if (start_pfn < end_pfn) {
380 : 63 : nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
381 : 63 : page_size_mask & (1<<PG_LEVEL_2M));
382 : 63 : pfn = end_pfn;
383 : : }
384 : :
385 : : #ifdef CONFIG_X86_64
386 : : /* big page (1G) range */
387 : 105 : start_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
388 : 105 : end_pfn = round_down(limit_pfn, PFN_DOWN(PUD_SIZE));
389 [ - + ]: 105 : if (start_pfn < end_pfn) {
390 : 0 : nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
391 : 0 : page_size_mask &
392 : : ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
393 : 0 : pfn = end_pfn;
394 : : }
395 : :
396 : : /* tail is not big page (1G) alignment */
397 : 105 : start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
398 : 105 : end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
399 [ - + ]: 105 : if (start_pfn < end_pfn) {
400 : 0 : nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
401 : 0 : page_size_mask & (1<<PG_LEVEL_2M));
402 : 0 : pfn = end_pfn;
403 : : }
404 : : #endif
405 : :
406 : : /* tail is not big page (2M) alignment */
407 : 105 : start_pfn = pfn;
408 : 105 : end_pfn = limit_pfn;
409 : 105 : nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
410 : :
411 [ + - ]: 105 : if (!after_bootmem)
412 : 105 : adjust_range_page_size_mask(mr, nr_range);
413 : :
414 : : /* try to merge same page size and continuous */
415 [ + + ]: 126 : for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
416 : 21 : unsigned long old_start;
417 [ + - ]: 21 : if (mr[i].end != mr[i+1].start ||
418 [ + - ]: 21 : mr[i].page_size_mask != mr[i+1].page_size_mask)
419 : 21 : continue;
420 : : /* move it */
421 : 0 : old_start = mr[i].start;
422 : 0 : memmove(&mr[i], &mr[i+1],
423 : 0 : (nr_range - 1 - i) * sizeof(struct map_range));
424 : 0 : mr[i--].start = old_start;
425 : 0 : nr_range--;
426 : : }
427 : :
428 : 105 : for (i = 0; i < nr_range; i++)
429 : : pr_debug(" [mem %#010lx-%#010lx] page %s\n",
430 : : mr[i].start, mr[i].end - 1,
431 : : page_size_string(&mr[i]));
432 : :
433 : 105 : return nr_range;
434 : : }
435 : :
436 : : struct range pfn_mapped[E820_MAX_ENTRIES];
437 : : int nr_pfn_mapped;
438 : :
439 : 105 : static void add_pfn_range_mapped(unsigned long start_pfn, unsigned long end_pfn)
440 : : {
441 : 105 : nr_pfn_mapped = add_range_with_merge(pfn_mapped, E820_MAX_ENTRIES,
442 : : nr_pfn_mapped, start_pfn, end_pfn);
443 : 105 : nr_pfn_mapped = clean_sort_range(pfn_mapped, E820_MAX_ENTRIES);
444 : :
445 : 105 : max_pfn_mapped = max(max_pfn_mapped, end_pfn);
446 : :
447 [ + - ]: 105 : if (start_pfn < (1UL<<(32-PAGE_SHIFT)))
448 : 105 : max_low_pfn_mapped = max(max_low_pfn_mapped,
449 : : min(end_pfn, 1UL<<(32-PAGE_SHIFT)));
450 : 105 : }
451 : :
452 : 38528 : bool pfn_range_is_mapped(unsigned long start_pfn, unsigned long end_pfn)
453 : : {
454 : 38528 : int i;
455 : :
456 [ + - ]: 38528 : for (i = 0; i < nr_pfn_mapped; i++)
457 [ + - ]: 38528 : if ((start_pfn >= pfn_mapped[i].start) &&
458 [ - + ]: 38528 : (end_pfn <= pfn_mapped[i].end))
459 : : return true;
460 : :
461 : : return false;
462 : : }
463 : :
464 : : /*
465 : : * Setup the direct mapping of the physical memory at PAGE_OFFSET.
466 : : * This runs before bootmem is initialized and gets pages directly from
467 : : * the physical memory. To access them they are temporarily mapped.
468 : : */
469 : 105 : unsigned long __ref init_memory_mapping(unsigned long start,
470 : : unsigned long end)
471 : : {
472 : 105 : struct map_range mr[NR_RANGE_MR];
473 : 105 : unsigned long ret = 0;
474 : 105 : int nr_range, i;
475 : :
476 : 105 : pr_debug("init_memory_mapping: [mem %#010lx-%#010lx]\n",
477 : : start, end - 1);
478 : :
479 : 105 : memset(mr, 0, sizeof(mr));
480 : 105 : nr_range = split_mem_range(mr, 0, start, end);
481 : :
482 [ + + ]: 336 : for (i = 0; i < nr_range; i++)
483 : 126 : ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
484 : 126 : mr[i].page_size_mask);
485 : :
486 : 105 : add_pfn_range_mapped(start >> PAGE_SHIFT, ret >> PAGE_SHIFT);
487 : :
488 : 105 : return ret >> PAGE_SHIFT;
489 : : }
490 : :
491 : : /*
492 : : * We need to iterate through the E820 memory map and create direct mappings
493 : : * for only E820_TYPE_RAM and E820_KERN_RESERVED regions. We cannot simply
494 : : * create direct mappings for all pfns from [0 to max_low_pfn) and
495 : : * [4GB to max_pfn) because of possible memory holes in high addresses
496 : : * that cannot be marked as UC by fixed/variable range MTRRs.
497 : : * Depending on the alignment of E820 ranges, this may possibly result
498 : : * in using smaller size (i.e. 4K instead of 2M or 1G) page tables.
499 : : *
500 : : * init_mem_mapping() calls init_range_memory_mapping() with big range.
501 : : * That range would have hole in the middle or ends, and only ram parts
502 : : * will be mapped in init_range_memory_mapping().
503 : : */
504 : 84 : static unsigned long __init init_range_memory_mapping(
505 : : unsigned long r_start,
506 : : unsigned long r_end)
507 : : {
508 : 84 : unsigned long start_pfn, end_pfn;
509 : 84 : unsigned long mapped_ram_size = 0;
510 : 84 : int i;
511 : :
512 [ + + ]: 252 : for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
513 : 168 : u64 start = clamp_val(PFN_PHYS(start_pfn), r_start, r_end);
514 : 168 : u64 end = clamp_val(PFN_PHYS(end_pfn), r_start, r_end);
515 [ + + ]: 168 : if (start >= end)
516 : 84 : continue;
517 : :
518 : : /*
519 : : * if it is overlapping with brk pgt, we need to
520 : : * alloc pgt buf from memblock instead.
521 : : */
522 : 84 : can_use_brk_pgt = max(start, (u64)pgt_buf_end<<PAGE_SHIFT) >=
523 : 84 : min(end, (u64)pgt_buf_top<<PAGE_SHIFT);
524 : 84 : init_memory_mapping(start, end);
525 : 84 : mapped_ram_size += end - start;
526 : 84 : can_use_brk_pgt = true;
527 : : }
528 : :
529 : 84 : return mapped_ram_size;
530 : : }
531 : :
532 : 42 : static unsigned long __init get_new_step_size(unsigned long step_size)
533 : : {
534 : : /*
535 : : * Initial mapped size is PMD_SIZE (2M).
536 : : * We can not set step_size to be PUD_SIZE (1G) yet.
537 : : * In worse case, when we cross the 1G boundary, and
538 : : * PG_LEVEL_2M is not set, we will need 1+1+512 pages (2M + 8k)
539 : : * to map 1G range with PTE. Hence we use one less than the
540 : : * difference of page table level shifts.
541 : : *
542 : : * Don't need to worry about overflow in the top-down case, on 32bit,
543 : : * when step_size is 0, round_down() returns 0 for start, and that
544 : : * turns it into 0x100000000ULL.
545 : : * In the bottom-up case, round_up(x, 0) returns 0 though too, which
546 : : * needs to be taken into consideration by the code below.
547 : : */
548 : 42 : return step_size << (PMD_SHIFT - PAGE_SHIFT - 1);
549 : : }
550 : :
551 : : /**
552 : : * memory_map_top_down - Map [map_start, map_end) top down
553 : : * @map_start: start address of the target memory range
554 : : * @map_end: end address of the target memory range
555 : : *
556 : : * This function will setup direct mapping for memory range
557 : : * [map_start, map_end) in top-down. That said, the page tables
558 : : * will be allocated at the end of the memory, and we map the
559 : : * memory in top-down.
560 : : */
561 : 21 : static void __init memory_map_top_down(unsigned long map_start,
562 : : unsigned long map_end)
563 : : {
564 : 21 : unsigned long real_end, start, last_start;
565 : 21 : unsigned long step_size;
566 : 21 : unsigned long addr;
567 : 21 : unsigned long mapped_ram_size = 0;
568 : :
569 : : /* xen has big range in reserved near end of ram, skip it at first.*/
570 : 21 : addr = memblock_find_in_range(map_start, map_end, PMD_SIZE, PMD_SIZE);
571 : 21 : real_end = addr + PMD_SIZE;
572 : :
573 : : /* step_size need to be small so pgt_buf from BRK could cover it */
574 : 21 : step_size = PMD_SIZE;
575 : 21 : max_pfn_mapped = 0; /* will get exact value next */
576 : 21 : min_pfn_mapped = real_end >> PAGE_SHIFT;
577 : 21 : last_start = start = real_end;
578 : :
579 : : /*
580 : : * We start from the top (end of memory) and go to the bottom.
581 : : * The memblock_find_in_range() gets us a block of RAM from the
582 : : * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
583 : : * for page table.
584 : : */
585 [ + + ]: 84 : while (last_start > map_start) {
586 [ + + ]: 63 : if (last_start > step_size) {
587 : 42 : start = round_down(last_start - 1, step_size);
588 : 42 : if (start < map_start)
589 : : start = map_start;
590 : : } else
591 : : start = map_start;
592 : 63 : mapped_ram_size += init_range_memory_mapping(start,
593 : : last_start);
594 : 63 : last_start = start;
595 : 63 : min_pfn_mapped = last_start >> PAGE_SHIFT;
596 [ + + ]: 63 : if (mapped_ram_size >= step_size)
597 : 42 : step_size = get_new_step_size(step_size);
598 : : }
599 : :
600 [ + - ]: 21 : if (real_end < map_end)
601 : 21 : init_range_memory_mapping(real_end, map_end);
602 : 21 : }
603 : :
604 : : /**
605 : : * memory_map_bottom_up - Map [map_start, map_end) bottom up
606 : : * @map_start: start address of the target memory range
607 : : * @map_end: end address of the target memory range
608 : : *
609 : : * This function will setup direct mapping for memory range
610 : : * [map_start, map_end) in bottom-up. Since we have limited the
611 : : * bottom-up allocation above the kernel, the page tables will
612 : : * be allocated just above the kernel and we map the memory
613 : : * in [map_start, map_end) in bottom-up.
614 : : */
615 : 0 : static void __init memory_map_bottom_up(unsigned long map_start,
616 : : unsigned long map_end)
617 : : {
618 : 0 : unsigned long next, start;
619 : 0 : unsigned long mapped_ram_size = 0;
620 : : /* step_size need to be small so pgt_buf from BRK could cover it */
621 : 0 : unsigned long step_size = PMD_SIZE;
622 : :
623 : 0 : start = map_start;
624 : 0 : min_pfn_mapped = start >> PAGE_SHIFT;
625 : :
626 : : /*
627 : : * We start from the bottom (@map_start) and go to the top (@map_end).
628 : : * The memblock_find_in_range() gets us a block of RAM from the
629 : : * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
630 : : * for page table.
631 : : */
632 [ # # ]: 0 : while (start < map_end) {
633 [ # # # # ]: 0 : if (step_size && map_end - start > step_size) {
634 : 0 : next = round_up(start + 1, step_size);
635 : 0 : if (next > map_end)
636 : : next = map_end;
637 : : } else {
638 : : next = map_end;
639 : : }
640 : :
641 : 0 : mapped_ram_size += init_range_memory_mapping(start, next);
642 : 0 : start = next;
643 : :
644 [ # # ]: 0 : if (mapped_ram_size >= step_size)
645 : 0 : step_size = get_new_step_size(step_size);
646 : : }
647 : 0 : }
648 : :
649 : 21 : void __init init_mem_mapping(void)
650 : : {
651 : 21 : unsigned long end;
652 : :
653 : 21 : pti_check_boottime_disable();
654 : 21 : probe_page_size_mask();
655 : 21 : setup_pcid();
656 : :
657 : : #ifdef CONFIG_X86_64
658 : 21 : end = max_pfn << PAGE_SHIFT;
659 : : #else
660 : : end = max_low_pfn << PAGE_SHIFT;
661 : : #endif
662 : :
663 : : /* the ISA range is always mapped regardless of memory holes */
664 : 21 : init_memory_mapping(0, ISA_END_ADDRESS);
665 : :
666 : : /* Init the trampoline, possibly with KASLR memory offset */
667 : 21 : init_trampoline();
668 : :
669 : : /*
670 : : * If the allocation is in bottom-up direction, we setup direct mapping
671 : : * in bottom-up, otherwise we setup direct mapping in top-down.
672 : : */
673 [ - + ]: 21 : if (memblock_bottom_up()) {
674 : 0 : unsigned long kernel_end = __pa_symbol(_end);
675 : :
676 : : /*
677 : : * we need two separate calls here. This is because we want to
678 : : * allocate page tables above the kernel. So we first map
679 : : * [kernel_end, end) to make memory above the kernel be mapped
680 : : * as soon as possible. And then use page tables allocated above
681 : : * the kernel to map [ISA_END_ADDRESS, kernel_end).
682 : : */
683 : 0 : memory_map_bottom_up(kernel_end, end);
684 : 0 : memory_map_bottom_up(ISA_END_ADDRESS, kernel_end);
685 : : } else {
686 : 21 : memory_map_top_down(ISA_END_ADDRESS, end);
687 : : }
688 : :
689 : : #ifdef CONFIG_X86_64
690 [ - + ]: 21 : if (max_pfn > max_low_pfn) {
691 : : /* can we preseve max_low_pfn ?*/
692 : 0 : max_low_pfn = max_pfn;
693 : : }
694 : : #else
695 : : early_ioremap_page_table_range_init();
696 : : #endif
697 : :
698 [ - + ]: 21 : load_cr3(swapper_pg_dir);
699 : 21 : __flush_tlb_all();
700 : :
701 : 21 : x86_init.hyper.init_mem_mapping();
702 : :
703 : 21 : early_memtest(0, max_pfn_mapped << PAGE_SHIFT);
704 : 21 : }
705 : :
706 : : /*
707 : : * Initialize an mm_struct to be used during poking and a pointer to be used
708 : : * during patching.
709 : : */
710 : 21 : void __init poking_init(void)
711 : : {
712 : 21 : spinlock_t *ptl;
713 : 21 : pte_t *ptep;
714 : :
715 : 21 : poking_mm = copy_init_mm();
716 [ - + ]: 21 : BUG_ON(!poking_mm);
717 : :
718 : : /*
719 : : * Randomize the poking address, but make sure that the following page
720 : : * will be mapped at the same PMD. We need 2 pages, so find space for 3,
721 : : * and adjust the address if the PMD ends after the first one.
722 : : */
723 [ - + - - ]: 21 : poking_addr = TASK_UNMAPPED_BASE;
724 : 21 : if (IS_ENABLED(CONFIG_RANDOMIZE_BASE))
725 : : poking_addr += (kaslr_get_random_long("Poking") & PAGE_MASK) %
726 : : (TASK_SIZE - TASK_UNMAPPED_BASE - 3 * PAGE_SIZE);
727 : :
728 [ - + ]: 21 : if (((poking_addr + PAGE_SIZE) & ~PMD_MASK) == 0)
729 : 0 : poking_addr += PAGE_SIZE;
730 : :
731 : : /*
732 : : * We need to trigger the allocation of the page-tables that will be
733 : : * needed for poking now. Later, poking may be performed in an atomic
734 : : * section, which might cause allocation to fail.
735 : : */
736 : 21 : ptep = get_locked_pte(poking_mm, poking_addr, &ptl);
737 [ - + ]: 21 : BUG_ON(!ptep);
738 : 21 : pte_unmap_unlock(ptep, ptl);
739 : 21 : }
740 : :
741 : : /*
742 : : * devmem_is_allowed() checks to see if /dev/mem access to a certain address
743 : : * is valid. The argument is a physical page number.
744 : : *
745 : : * On x86, access has to be given to the first megabyte of RAM because that
746 : : * area traditionally contains BIOS code and data regions used by X, dosemu,
747 : : * and similar apps. Since they map the entire memory range, the whole range
748 : : * must be allowed (for mapping), but any areas that would otherwise be
749 : : * disallowed are flagged as being "zero filled" instead of rejected.
750 : : * Access has to be given to non-kernel-ram areas as well, these contain the
751 : : * PCI mmio resources as well as potential bios/acpi data regions.
752 : : */
753 : 0 : int devmem_is_allowed(unsigned long pagenr)
754 : : {
755 [ # # ]: 0 : if (region_intersects(PFN_PHYS(pagenr), PAGE_SIZE,
756 : : IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE)
757 : : != REGION_DISJOINT) {
758 : : /*
759 : : * For disallowed memory regions in the low 1MB range,
760 : : * request that the page be shown as all zeros.
761 : : */
762 [ # # ]: 0 : if (pagenr < 256)
763 : : return 2;
764 : :
765 : 0 : return 0;
766 : : }
767 : :
768 : : /*
769 : : * This must follow RAM test, since System RAM is considered a
770 : : * restricted resource under CONFIG_STRICT_IOMEM.
771 : : */
772 [ # # ]: 0 : if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) {
773 : : /* Low 1MB bypasses iomem restrictions. */
774 [ # # ]: 0 : if (pagenr < 256)
775 : : return 1;
776 : :
777 : 0 : return 0;
778 : : }
779 : :
780 : : return 1;
781 : : }
782 : :
783 : 84 : void free_init_pages(const char *what, unsigned long begin, unsigned long end)
784 : : {
785 : 84 : unsigned long begin_aligned, end_aligned;
786 : :
787 : : /* Make sure boundaries are page aligned */
788 : 84 : begin_aligned = PAGE_ALIGN(begin);
789 : 84 : end_aligned = end & PAGE_MASK;
790 : :
791 [ - + - + ]: 84 : if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
792 : 0 : begin = begin_aligned;
793 : 0 : end = end_aligned;
794 : : }
795 : :
796 [ + - ]: 84 : if (begin >= end)
797 : : return;
798 : :
799 : : /*
800 : : * If debugging page accesses then do not free this memory but
801 : : * mark them not present - any buggy init-section access will
802 : : * create a kernel page fault:
803 : : */
804 : 84 : if (debug_pagealloc_enabled()) {
805 : : pr_info("debug: unmapping init [mem %#010lx-%#010lx]\n",
806 : : begin, end - 1);
807 : : /*
808 : : * Inform kmemleak about the hole in the memory since the
809 : : * corresponding pages will be unmapped.
810 : : */
811 : : kmemleak_free_part((void *)begin, end - begin);
812 : : set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
813 : : } else {
814 : : /*
815 : : * We just marked the kernel text read only above, now that
816 : : * we are going to free part of that, we need to make that
817 : : * writeable and non-executable first.
818 : : */
819 : 84 : set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
820 : 84 : set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
821 : :
822 : 84 : free_reserved_area((void *)begin, (void *)end,
823 : : POISON_FREE_INITMEM, what);
824 : : }
825 : : }
826 : :
827 : : /*
828 : : * begin/end can be in the direct map or the "high kernel mapping"
829 : : * used for the kernel image only. free_init_pages() will do the
830 : : * right thing for either kind of address.
831 : : */
832 : 63 : void free_kernel_image_pages(const char *what, void *begin, void *end)
833 : : {
834 : 63 : unsigned long begin_ul = (unsigned long)begin;
835 : 63 : unsigned long end_ul = (unsigned long)end;
836 : 63 : unsigned long len_pages = (end_ul - begin_ul) >> PAGE_SHIFT;
837 : :
838 : 63 : free_init_pages(what, begin_ul, end_ul);
839 : :
840 : : /*
841 : : * PTI maps some of the kernel into userspace. For performance,
842 : : * this includes some kernel areas that do not contain secrets.
843 : : * Those areas might be adjacent to the parts of the kernel image
844 : : * being freed, which may contain secrets. Remove the "high kernel
845 : : * image mapping" for these freed areas, ensuring they are not even
846 : : * potentially vulnerable to Meltdown regardless of the specific
847 : : * optimizations PTI is currently using.
848 : : *
849 : : * The "noalias" prevents unmapping the direct map alias which is
850 : : * needed to access the freed pages.
851 : : *
852 : : * This is only valid for 64bit kernels. 32bit has only one mapping
853 : : * which can't be treated in this way for obvious reasons.
854 : : */
855 [ - - + ]: 63 : if (IS_ENABLED(CONFIG_X86_64) && cpu_feature_enabled(X86_FEATURE_PTI))
856 : 0 : set_memory_np_noalias(begin_ul, len_pages);
857 : 63 : }
858 : :
859 : 21 : void __weak mem_encrypt_free_decrypted_mem(void) { }
860 : :
861 : 21 : void __ref free_initmem(void)
862 : : {
863 : 21 : e820__reallocate_tables();
864 : :
865 : 21 : mem_encrypt_free_decrypted_mem();
866 : :
867 : 21 : free_kernel_image_pages("unused kernel image (initmem)",
868 : : &__init_begin, &__init_end);
869 : 21 : }
870 : :
871 : : #ifdef CONFIG_BLK_DEV_INITRD
872 : 0 : void __init free_initrd_mem(unsigned long start, unsigned long end)
873 : : {
874 : : /*
875 : : * end could be not aligned, and We can not align that,
876 : : * decompresser could be confused by aligned initrd_end
877 : : * We already reserve the end partial page before in
878 : : * - i386_start_kernel()
879 : : * - x86_64_start_kernel()
880 : : * - relocate_initrd()
881 : : * So here We can do PAGE_ALIGN() safely to get partial page to be freed
882 : : */
883 : 0 : free_init_pages("initrd", start, PAGE_ALIGN(end));
884 : 0 : }
885 : : #endif
886 : :
887 : : /*
888 : : * Calculate the precise size of the DMA zone (first 16 MB of RAM),
889 : : * and pass it to the MM layer - to help it set zone watermarks more
890 : : * accurately.
891 : : *
892 : : * Done on 64-bit systems only for the time being, although 32-bit systems
893 : : * might benefit from this as well.
894 : : */
895 : 21 : void __init memblock_find_dma_reserve(void)
896 : : {
897 : : #ifdef CONFIG_X86_64
898 : 21 : u64 nr_pages = 0, nr_free_pages = 0;
899 : 21 : unsigned long start_pfn, end_pfn;
900 : 21 : phys_addr_t start_addr, end_addr;
901 : 21 : int i;
902 : 21 : u64 u;
903 : :
904 : : /*
905 : : * Iterate over all memory ranges (free and reserved ones alike),
906 : : * to calculate the total number of pages in the first 16 MB of RAM:
907 : : */
908 : 21 : nr_pages = 0;
909 [ + + ]: 63 : for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
910 : 42 : start_pfn = min(start_pfn, MAX_DMA_PFN);
911 : 42 : end_pfn = min(end_pfn, MAX_DMA_PFN);
912 : :
913 : 42 : nr_pages += end_pfn - start_pfn;
914 : : }
915 : :
916 : : /*
917 : : * Iterate over free memory ranges to calculate the number of free
918 : : * pages in the DMA zone, while not counting potential partial
919 : : * pages at the beginning or the end of the range:
920 : : */
921 : 21 : nr_free_pages = 0;
922 [ + + ]: 84 : for_each_free_mem_range(u, NUMA_NO_NODE, MEMBLOCK_NONE, &start_addr, &end_addr, NULL) {
923 : 63 : start_pfn = min_t(unsigned long, PFN_UP(start_addr), MAX_DMA_PFN);
924 : 63 : end_pfn = min_t(unsigned long, PFN_DOWN(end_addr), MAX_DMA_PFN);
925 : :
926 [ + + ]: 63 : if (start_pfn < end_pfn)
927 : 42 : nr_free_pages += end_pfn - start_pfn;
928 : : }
929 : :
930 : 21 : set_dma_reserve(nr_pages - nr_free_pages);
931 : : #endif
932 : 21 : }
933 : :
934 : 21 : void __init zone_sizes_init(void)
935 : : {
936 : 21 : unsigned long max_zone_pfns[MAX_NR_ZONES];
937 : :
938 : 21 : memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
939 : :
940 : : #ifdef CONFIG_ZONE_DMA
941 : 21 : max_zone_pfns[ZONE_DMA] = min(MAX_DMA_PFN, max_low_pfn);
942 : : #endif
943 : : #ifdef CONFIG_ZONE_DMA32
944 : 21 : max_zone_pfns[ZONE_DMA32] = min(MAX_DMA32_PFN, max_low_pfn);
945 : : #endif
946 : 21 : max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
947 : : #ifdef CONFIG_HIGHMEM
948 : : max_zone_pfns[ZONE_HIGHMEM] = max_pfn;
949 : : #endif
950 : :
951 : 21 : free_area_init_nodes(max_zone_pfns);
952 : 21 : }
953 : :
954 : : __visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
955 : : .loaded_mm = &init_mm,
956 : : .next_asid = 1,
957 : : .cr4 = ~0UL, /* fail hard if we screw up cr4 shadow initialization */
958 : : };
959 : : EXPORT_PER_CPU_SYMBOL(cpu_tlbstate);
960 : :
961 : 168 : void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
962 : : {
963 : : /* entry 0 MUST be WB (hardwired to speed up translations) */
964 [ - + ]: 168 : BUG_ON(!entry && cache != _PAGE_CACHE_MODE_WB);
965 : :
966 : 168 : __cachemode2pte_tbl[cache] = __cm_idx2pte(entry);
967 : 168 : __pte2cachemode_tbl[entry] = cache;
968 : 168 : }
969 : :
970 : : #ifdef CONFIG_SWAP
971 : 0 : unsigned long max_swapfile_size(void)
972 : : {
973 : 0 : unsigned long pages;
974 : :
975 : 0 : pages = generic_max_swapfile_size();
976 : :
977 [ # # # # ]: 0 : if (boot_cpu_has_bug(X86_BUG_L1TF) && l1tf_mitigation != L1TF_MITIGATION_OFF) {
978 : : /* Limit the swap file size to MAX_PA/2 for L1TF workaround */
979 : 0 : unsigned long long l1tf_limit = l1tf_pfn_limit();
980 : : /*
981 : : * We encode swap offsets also with 3 bits below those for pfn
982 : : * which makes the usable limit higher.
983 : : */
984 : : #if CONFIG_PGTABLE_LEVELS > 2
985 : 0 : l1tf_limit <<= PAGE_SHIFT - SWP_OFFSET_FIRST_BIT;
986 : : #endif
987 : 0 : pages = min_t(unsigned long long, l1tf_limit, pages);
988 : : }
989 : 0 : return pages;
990 : : }
991 : : #endif
|
