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#include <linux/execmem.h>
  11
  12#include <asm/set_memory.h>
  13#include <asm/cpu_device_id.h>
  14#include <asm/e820/api.h>
  15#include <asm/init.h>
  16#include <asm/page.h>
  17#include <asm/page_types.h>
  18#include <asm/sections.h>
  19#include <asm/setup.h>
  20#include <asm/tlbflush.h>
  21#include <asm/tlb.h>
  22#include <asm/proto.h>
  23#include <asm/dma.h>		/* for MAX_DMA_PFN */
  24#include <asm/kaslr.h>
  25#include <asm/hypervisor.h>
  26#include <asm/cpufeature.h>
  27#include <asm/pti.h>
  28#include <asm/text-patching.h>
  29#include <asm/memtype.h>
  30#include <asm/paravirt.h>
  31
  32/*
  33 * We need to define the tracepoints somewhere, and tlb.c
  34 * is only compiled when SMP=y.
  35 */
  36#include <trace/events/tlb.h>
  37
  38#include "mm_internal.h"
  39
  40/*
  41 * Tables translating between page_cache_type_t and pte encoding.
  42 *
  43 * The default values are defined statically as minimal supported mode;
  44 * WC and WT fall back to UC-.  pat_init() updates these values to support
  45 * more cache modes, WC and WT, when it is safe to do so.  See pat_init()
  46 * for the details.  Note, __early_ioremap() used during early boot-time
  47 * takes pgprot_t (pte encoding) and does not use these tables.
  48 *
  49 *   Index into __cachemode2pte_tbl[] is the cachemode.
  50 *
  51 *   Index into __pte2cachemode_tbl[] are the caching attribute bits of the pte
  52 *   (_PAGE_PWT, _PAGE_PCD, _PAGE_PAT) at index bit positions 0, 1, 2.
  53 */
  54static uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM] = {
  55	[_PAGE_CACHE_MODE_WB      ]	= 0         | 0        ,
  56	[_PAGE_CACHE_MODE_WC      ]	= 0         | _PAGE_PCD,
  57	[_PAGE_CACHE_MODE_UC_MINUS]	= 0         | _PAGE_PCD,
  58	[_PAGE_CACHE_MODE_UC      ]	= _PAGE_PWT | _PAGE_PCD,
  59	[_PAGE_CACHE_MODE_WT      ]	= 0         | _PAGE_PCD,
  60	[_PAGE_CACHE_MODE_WP      ]	= 0         | _PAGE_PCD,
  61};
  62
  63unsigned long cachemode2protval(enum page_cache_mode pcm)
  64{
  65	if (likely(pcm == 0))
  66		return 0;
  67	return __cachemode2pte_tbl[pcm];
  68}
  69EXPORT_SYMBOL(cachemode2protval);
  70
  71static uint8_t __pte2cachemode_tbl[8] = {
  72	[__pte2cm_idx( 0        | 0         | 0        )] = _PAGE_CACHE_MODE_WB,
  73	[__pte2cm_idx(_PAGE_PWT | 0         | 0        )] = _PAGE_CACHE_MODE_UC_MINUS,
  74	[__pte2cm_idx( 0        | _PAGE_PCD | 0        )] = _PAGE_CACHE_MODE_UC_MINUS,
  75	[__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | 0        )] = _PAGE_CACHE_MODE_UC,
  76	[__pte2cm_idx( 0        | 0         | _PAGE_PAT)] = _PAGE_CACHE_MODE_WB,
  77	[__pte2cm_idx(_PAGE_PWT | 0         | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
  78	[__pte2cm_idx(0         | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
  79	[__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC,
  80};
  81
  82/*
  83 * Check that the write-protect PAT entry is set for write-protect.
  84 * To do this without making assumptions how PAT has been set up (Xen has
  85 * another layout than the kernel), translate the _PAGE_CACHE_MODE_WP cache
  86 * mode via the __cachemode2pte_tbl[] into protection bits (those protection
  87 * bits will select a cache mode of WP or better), and then translate the
  88 * protection bits back into the cache mode using __pte2cm_idx() and the
  89 * __pte2cachemode_tbl[] array. This will return the really used cache mode.
  90 */
  91bool x86_has_pat_wp(void)
  92{
  93	uint16_t prot = __cachemode2pte_tbl[_PAGE_CACHE_MODE_WP];
  94
  95	return __pte2cachemode_tbl[__pte2cm_idx(prot)] == _PAGE_CACHE_MODE_WP;
  96}
  97
  98enum page_cache_mode pgprot2cachemode(pgprot_t pgprot)
  99{
 100	unsigned long masked;
 101
 102	masked = pgprot_val(pgprot) & _PAGE_CACHE_MASK;
 103	if (likely(masked == 0))
 104		return 0;
 105	return __pte2cachemode_tbl[__pte2cm_idx(masked)];
 106}
 107
 108static unsigned long __initdata pgt_buf_start;
 109static unsigned long __initdata pgt_buf_end;
 110static unsigned long __initdata pgt_buf_top;
 111
 112static unsigned long min_pfn_mapped;
 113
 114static bool __initdata can_use_brk_pgt = true;
 115
 116/*
 117 * Pages returned are already directly mapped.
 118 *
 119 * Changing that is likely to break Xen, see commit:
 120 *
 121 *    279b706 x86,xen: introduce x86_init.mapping.pagetable_reserve
 122 *
 123 * for detailed information.
 124 */
 125__ref void *alloc_low_pages(unsigned int num)
 126{
 127	unsigned long pfn;
 128	int i;
 129
 130	if (after_bootmem) {
 131		unsigned int order;
 132
 133		order = get_order((unsigned long)num << PAGE_SHIFT);
 134		return (void *)__get_free_pages(GFP_ATOMIC | __GFP_ZERO, order);
 
 135	}
 136
 137	if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) {
 138		unsigned long ret = 0;
 139
 140		if (min_pfn_mapped < max_pfn_mapped) {
 141			ret = memblock_phys_alloc_range(
 142					PAGE_SIZE * num, PAGE_SIZE,
 143					min_pfn_mapped << PAGE_SHIFT,
 144					max_pfn_mapped << PAGE_SHIFT);
 145		}
 146		if (!ret && can_use_brk_pgt)
 147			ret = __pa(extend_brk(PAGE_SIZE * num, PAGE_SIZE));
 148
 149		if (!ret)
 150			panic("alloc_low_pages: can not alloc memory");
 151
 152		pfn = ret >> PAGE_SHIFT;
 153	} else {
 154		pfn = pgt_buf_end;
 155		pgt_buf_end += num;
 
 
 156	}
 157
 158	for (i = 0; i < num; i++) {
 159		void *adr;
 160
 161		adr = __va((pfn + i) << PAGE_SHIFT);
 162		clear_page(adr);
 163	}
 164
 165	return __va(pfn << PAGE_SHIFT);
 166}
 167
 168/*
 169 * By default need to be able to allocate page tables below PGD firstly for
 170 * the 0-ISA_END_ADDRESS range and secondly for the initial PMD_SIZE mapping.
 171 * With KASLR memory randomization, depending on the machine e820 memory and the
 172 * PUD alignment, twice that many pages may be needed when KASLR memory
 173 * randomization is enabled.
 174 */
 175
 176#ifndef CONFIG_X86_5LEVEL
 177#define INIT_PGD_PAGE_TABLES    3
 178#else
 179#define INIT_PGD_PAGE_TABLES    4
 180#endif
 181
 182#ifndef CONFIG_RANDOMIZE_MEMORY
 183#define INIT_PGD_PAGE_COUNT      (2 * INIT_PGD_PAGE_TABLES)
 184#else
 185#define INIT_PGD_PAGE_COUNT      (4 * INIT_PGD_PAGE_TABLES)
 186#endif
 187
 188#define INIT_PGT_BUF_SIZE	(INIT_PGD_PAGE_COUNT * PAGE_SIZE)
 189RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE);
 190void  __init early_alloc_pgt_buf(void)
 191{
 192	unsigned long tables = INIT_PGT_BUF_SIZE;
 193	phys_addr_t base;
 194
 195	base = __pa(extend_brk(tables, PAGE_SIZE));
 196
 197	pgt_buf_start = base >> PAGE_SHIFT;
 198	pgt_buf_end = pgt_buf_start;
 199	pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);
 200}
 201
 202int after_bootmem;
 203
 204early_param_on_off("gbpages", "nogbpages", direct_gbpages, CONFIG_X86_DIRECT_GBPAGES);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 205
 206struct map_range {
 207	unsigned long start;
 208	unsigned long end;
 209	unsigned page_size_mask;
 210};
 211
 212static int page_size_mask;
 213
 214/*
 215 * Save some of cr4 feature set we're using (e.g.  Pentium 4MB
 216 * enable and PPro Global page enable), so that any CPU's that boot
 217 * up after us can get the correct flags. Invoked on the boot CPU.
 218 */
 219static inline void cr4_set_bits_and_update_boot(unsigned long mask)
 220{
 221	mmu_cr4_features |= mask;
 222	if (trampoline_cr4_features)
 223		*trampoline_cr4_features = mmu_cr4_features;
 224	cr4_set_bits(mask);
 225}
 226
 227static void __init probe_page_size_mask(void)
 228{
 
 
 
 229	/*
 230	 * For pagealloc debugging, identity mapping will use small pages.
 231	 * This will simplify cpa(), which otherwise needs to support splitting
 232	 * large pages into small in interrupt context, etc.
 233	 */
 234	if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled())
 
 
 235		page_size_mask |= 1 << PG_LEVEL_2M;
 236	else
 237		direct_gbpages = 0;
 238
 239	/* Enable PSE if available */
 240	if (boot_cpu_has(X86_FEATURE_PSE))
 241		cr4_set_bits_and_update_boot(X86_CR4_PSE);
 242
 243	/* Enable PGE if available */
 244	__supported_pte_mask &= ~_PAGE_GLOBAL;
 245	if (boot_cpu_has(X86_FEATURE_PGE)) {
 246		cr4_set_bits_and_update_boot(X86_CR4_PGE);
 247		__supported_pte_mask |= _PAGE_GLOBAL;
 248	}
 249
 250	/* By the default is everything supported: */
 251	__default_kernel_pte_mask = __supported_pte_mask;
 252	/* Except when with PTI where the kernel is mostly non-Global: */
 253	if (cpu_feature_enabled(X86_FEATURE_PTI))
 254		__default_kernel_pte_mask &= ~_PAGE_GLOBAL;
 255
 256	/* Enable 1 GB linear kernel mappings if available: */
 257	if (direct_gbpages && boot_cpu_has(X86_FEATURE_GBPAGES)) {
 258		printk(KERN_INFO "Using GB pages for direct mapping\n");
 259		page_size_mask |= 1 << PG_LEVEL_1G;
 260	} else {
 261		direct_gbpages = 0;
 262	}
 263}
 264
 265/*
 266 * INVLPG may not properly flush Global entries on
 267 * these CPUs.  New microcode fixes the issue.
 268 */
 269static const struct x86_cpu_id invlpg_miss_ids[] = {
 270	X86_MATCH_VFM(INTEL_ALDERLAKE,	    0x2e),
 271	X86_MATCH_VFM(INTEL_ALDERLAKE_L,    0x42c),
 272	X86_MATCH_VFM(INTEL_ATOM_GRACEMONT, 0x11),
 273	X86_MATCH_VFM(INTEL_RAPTORLAKE,	    0x118),
 274	X86_MATCH_VFM(INTEL_RAPTORLAKE_P,   0x4117),
 275	X86_MATCH_VFM(INTEL_RAPTORLAKE_S,   0x2e),
 276	{}
 277};
 278
 279static void setup_pcid(void)
 280{
 281	const struct x86_cpu_id *invlpg_miss_match;
 282
 283	if (!IS_ENABLED(CONFIG_X86_64))
 284		return;
 285
 286	if (!boot_cpu_has(X86_FEATURE_PCID))
 287		return;
 288
 289	invlpg_miss_match = x86_match_cpu(invlpg_miss_ids);
 290
 291	if (invlpg_miss_match &&
 292	    boot_cpu_data.microcode < invlpg_miss_match->driver_data) {
 293		pr_info("Incomplete global flushes, disabling PCID");
 294		setup_clear_cpu_cap(X86_FEATURE_PCID);
 295		return;
 296	}
 297
 298	if (boot_cpu_has(X86_FEATURE_PGE)) {
 299		/*
 300		 * This can't be cr4_set_bits_and_update_boot() -- the
 301		 * trampoline code can't handle CR4.PCIDE and it wouldn't
 302		 * do any good anyway.  Despite the name,
 303		 * cr4_set_bits_and_update_boot() doesn't actually cause
 304		 * the bits in question to remain set all the way through
 305		 * the secondary boot asm.
 306		 *
 307		 * Instead, we brute-force it and set CR4.PCIDE manually in
 308		 * start_secondary().
 309		 */
 310		cr4_set_bits(X86_CR4_PCIDE);
 311	} else {
 312		/*
 313		 * flush_tlb_all(), as currently implemented, won't work if
 314		 * PCID is on but PGE is not.  Since that combination
 315		 * doesn't exist on real hardware, there's no reason to try
 316		 * to fully support it, but it's polite to avoid corrupting
 317		 * data if we're on an improperly configured VM.
 318		 */
 319		setup_clear_cpu_cap(X86_FEATURE_PCID);
 320	}
 321}
 322
 323#ifdef CONFIG_X86_32
 324#define NR_RANGE_MR 3
 325#else /* CONFIG_X86_64 */
 326#define NR_RANGE_MR 5
 327#endif
 328
 329static int __meminit save_mr(struct map_range *mr, int nr_range,
 330			     unsigned long start_pfn, unsigned long end_pfn,
 331			     unsigned long page_size_mask)
 332{
 333	if (start_pfn < end_pfn) {
 334		if (nr_range >= NR_RANGE_MR)
 335			panic("run out of range for init_memory_mapping\n");
 336		mr[nr_range].start = start_pfn<<PAGE_SHIFT;
 337		mr[nr_range].end   = end_pfn<<PAGE_SHIFT;
 338		mr[nr_range].page_size_mask = page_size_mask;
 339		nr_range++;
 340	}
 341
 342	return nr_range;
 343}
 344
 345/*
 346 * adjust the page_size_mask for small range to go with
 347 *	big page size instead small one if nearby are ram too.
 348 */
 349static void __ref adjust_range_page_size_mask(struct map_range *mr,
 350							 int nr_range)
 351{
 352	int i;
 353
 354	for (i = 0; i < nr_range; i++) {
 355		if ((page_size_mask & (1<<PG_LEVEL_2M)) &&
 356		    !(mr[i].page_size_mask & (1<<PG_LEVEL_2M))) {
 357			unsigned long start = round_down(mr[i].start, PMD_SIZE);
 358			unsigned long end = round_up(mr[i].end, PMD_SIZE);
 359
 360#ifdef CONFIG_X86_32
 361			if ((end >> PAGE_SHIFT) > max_low_pfn)
 362				continue;
 363#endif
 364
 365			if (memblock_is_region_memory(start, end - start))
 366				mr[i].page_size_mask |= 1<<PG_LEVEL_2M;
 367		}
 368		if ((page_size_mask & (1<<PG_LEVEL_1G)) &&
 369		    !(mr[i].page_size_mask & (1<<PG_LEVEL_1G))) {
 370			unsigned long start = round_down(mr[i].start, PUD_SIZE);
 371			unsigned long end = round_up(mr[i].end, PUD_SIZE);
 372
 373			if (memblock_is_region_memory(start, end - start))
 374				mr[i].page_size_mask |= 1<<PG_LEVEL_1G;
 375		}
 376	}
 377}
 378
 379static const char *page_size_string(struct map_range *mr)
 380{
 381	static const char str_1g[] = "1G";
 382	static const char str_2m[] = "2M";
 383	static const char str_4m[] = "4M";
 384	static const char str_4k[] = "4k";
 385
 386	if (mr->page_size_mask & (1<<PG_LEVEL_1G))
 387		return str_1g;
 388	/*
 389	 * 32-bit without PAE has a 4M large page size.
 390	 * PG_LEVEL_2M is misnamed, but we can at least
 391	 * print out the right size in the string.
 392	 */
 393	if (IS_ENABLED(CONFIG_X86_32) &&
 394	    !IS_ENABLED(CONFIG_X86_PAE) &&
 395	    mr->page_size_mask & (1<<PG_LEVEL_2M))
 396		return str_4m;
 397
 398	if (mr->page_size_mask & (1<<PG_LEVEL_2M))
 399		return str_2m;
 400
 401	return str_4k;
 402}
 403
 404static int __meminit split_mem_range(struct map_range *mr, int nr_range,
 405				     unsigned long start,
 406				     unsigned long end)
 407{
 408	unsigned long start_pfn, end_pfn, limit_pfn;
 409	unsigned long pfn;
 410	int i;
 411
 412	limit_pfn = PFN_DOWN(end);
 413
 414	/* head if not big page alignment ? */
 415	pfn = start_pfn = PFN_DOWN(start);
 416#ifdef CONFIG_X86_32
 417	/*
 418	 * Don't use a large page for the first 2/4MB of memory
 419	 * because there are often fixed size MTRRs in there
 420	 * and overlapping MTRRs into large pages can cause
 421	 * slowdowns.
 422	 */
 423	if (pfn == 0)
 424		end_pfn = PFN_DOWN(PMD_SIZE);
 425	else
 426		end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
 427#else /* CONFIG_X86_64 */
 428	end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
 429#endif
 430	if (end_pfn > limit_pfn)
 431		end_pfn = limit_pfn;
 432	if (start_pfn < end_pfn) {
 433		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 434		pfn = end_pfn;
 435	}
 436
 437	/* big page (2M) range */
 438	start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
 439#ifdef CONFIG_X86_32
 440	end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
 441#else /* CONFIG_X86_64 */
 442	end_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
 443	if (end_pfn > round_down(limit_pfn, PFN_DOWN(PMD_SIZE)))
 444		end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
 445#endif
 446
 447	if (start_pfn < end_pfn) {
 448		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 449				page_size_mask & (1<<PG_LEVEL_2M));
 450		pfn = end_pfn;
 451	}
 452
 453#ifdef CONFIG_X86_64
 454	/* big page (1G) range */
 455	start_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
 456	end_pfn = round_down(limit_pfn, PFN_DOWN(PUD_SIZE));
 457	if (start_pfn < end_pfn) {
 458		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 459				page_size_mask &
 460				 ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
 461		pfn = end_pfn;
 462	}
 463
 464	/* tail is not big page (1G) alignment */
 465	start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
 466	end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
 467	if (start_pfn < end_pfn) {
 468		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 469				page_size_mask & (1<<PG_LEVEL_2M));
 470		pfn = end_pfn;
 471	}
 472#endif
 473
 474	/* tail is not big page (2M) alignment */
 475	start_pfn = pfn;
 476	end_pfn = limit_pfn;
 477	nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 478
 479	if (!after_bootmem)
 480		adjust_range_page_size_mask(mr, nr_range);
 481
 482	/* try to merge same page size and continuous */
 483	for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
 484		unsigned long old_start;
 485		if (mr[i].end != mr[i+1].start ||
 486		    mr[i].page_size_mask != mr[i+1].page_size_mask)
 487			continue;
 488		/* move it */
 489		old_start = mr[i].start;
 490		memmove(&mr[i], &mr[i+1],
 491			(nr_range - 1 - i) * sizeof(struct map_range));
 492		mr[i--].start = old_start;
 493		nr_range--;
 494	}
 495
 496	for (i = 0; i < nr_range; i++)
 497		pr_debug(" [mem %#010lx-%#010lx] page %s\n",
 498				mr[i].start, mr[i].end - 1,
 499				page_size_string(&mr[i]));
 
 500
 501	return nr_range;
 502}
 503
 504struct range pfn_mapped[E820_MAX_ENTRIES];
 505int nr_pfn_mapped;
 506
 507static void add_pfn_range_mapped(unsigned long start_pfn, unsigned long end_pfn)
 508{
 509	nr_pfn_mapped = add_range_with_merge(pfn_mapped, E820_MAX_ENTRIES,
 510					     nr_pfn_mapped, start_pfn, end_pfn);
 511	nr_pfn_mapped = clean_sort_range(pfn_mapped, E820_MAX_ENTRIES);
 512
 513	max_pfn_mapped = max(max_pfn_mapped, end_pfn);
 514
 515	if (start_pfn < (1UL<<(32-PAGE_SHIFT)))
 516		max_low_pfn_mapped = max(max_low_pfn_mapped,
 517					 min(end_pfn, 1UL<<(32-PAGE_SHIFT)));
 518}
 519
 520bool pfn_range_is_mapped(unsigned long start_pfn, unsigned long end_pfn)
 521{
 522	int i;
 523
 524	for (i = 0; i < nr_pfn_mapped; i++)
 525		if ((start_pfn >= pfn_mapped[i].start) &&
 526		    (end_pfn <= pfn_mapped[i].end))
 527			return true;
 528
 529	return false;
 530}
 531
 532/*
 533 * Setup the direct mapping of the physical memory at PAGE_OFFSET.
 534 * This runs before bootmem is initialized and gets pages directly from
 535 * the physical memory. To access them they are temporarily mapped.
 536 */
 537unsigned long __ref init_memory_mapping(unsigned long start,
 538					unsigned long end, pgprot_t prot)
 539{
 540	struct map_range mr[NR_RANGE_MR];
 541	unsigned long ret = 0;
 542	int nr_range, i;
 543
 544	pr_debug("init_memory_mapping: [mem %#010lx-%#010lx]\n",
 545	       start, end - 1);
 546
 547	memset(mr, 0, sizeof(mr));
 548	nr_range = split_mem_range(mr, 0, start, end);
 549
 550	for (i = 0; i < nr_range; i++)
 551		ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
 552						   mr[i].page_size_mask,
 553						   prot);
 554
 555	add_pfn_range_mapped(start >> PAGE_SHIFT, ret >> PAGE_SHIFT);
 556
 557	return ret >> PAGE_SHIFT;
 558}
 559
 560/*
 561 * We need to iterate through the E820 memory map and create direct mappings
 562 * for only E820_TYPE_RAM and E820_KERN_RESERVED regions. We cannot simply
 563 * create direct mappings for all pfns from [0 to max_low_pfn) and
 564 * [4GB to max_pfn) because of possible memory holes in high addresses
 565 * that cannot be marked as UC by fixed/variable range MTRRs.
 566 * Depending on the alignment of E820 ranges, this may possibly result
 567 * in using smaller size (i.e. 4K instead of 2M or 1G) page tables.
 568 *
 569 * init_mem_mapping() calls init_range_memory_mapping() with big range.
 570 * That range would have hole in the middle or ends, and only ram parts
 571 * will be mapped in init_range_memory_mapping().
 572 */
 573static unsigned long __init init_range_memory_mapping(
 574					   unsigned long r_start,
 575					   unsigned long r_end)
 576{
 577	unsigned long start_pfn, end_pfn;
 578	unsigned long mapped_ram_size = 0;
 579	int i;
 580
 581	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
 582		u64 start = clamp_val(PFN_PHYS(start_pfn), r_start, r_end);
 583		u64 end = clamp_val(PFN_PHYS(end_pfn), r_start, r_end);
 584		if (start >= end)
 585			continue;
 586
 587		/*
 588		 * if it is overlapping with brk pgt, we need to
 589		 * alloc pgt buf from memblock instead.
 590		 */
 591		can_use_brk_pgt = max(start, (u64)pgt_buf_end<<PAGE_SHIFT) >=
 592				    min(end, (u64)pgt_buf_top<<PAGE_SHIFT);
 593		init_memory_mapping(start, end, PAGE_KERNEL);
 594		mapped_ram_size += end - start;
 595		can_use_brk_pgt = true;
 596	}
 597
 598	return mapped_ram_size;
 599}
 600
 601static unsigned long __init get_new_step_size(unsigned long step_size)
 602{
 603	/*
 604	 * Initial mapped size is PMD_SIZE (2M).
 
 
 
 605	 * We can not set step_size to be PUD_SIZE (1G) yet.
 606	 * In worse case, when we cross the 1G boundary, and
 607	 * PG_LEVEL_2M is not set, we will need 1+1+512 pages (2M + 8k)
 608	 * to map 1G range with PTE. Hence we use one less than the
 609	 * difference of page table level shifts.
 610	 *
 611	 * Don't need to worry about overflow in the top-down case, on 32bit,
 612	 * when step_size is 0, round_down() returns 0 for start, and that
 613	 * turns it into 0x100000000ULL.
 614	 * In the bottom-up case, round_up(x, 0) returns 0 though too, which
 615	 * needs to be taken into consideration by the code below.
 616	 */
 617	return step_size << (PMD_SHIFT - PAGE_SHIFT - 1);
 618}
 619
 620/**
 621 * memory_map_top_down - Map [map_start, map_end) top down
 622 * @map_start: start address of the target memory range
 623 * @map_end: end address of the target memory range
 624 *
 625 * This function will setup direct mapping for memory range
 626 * [map_start, map_end) in top-down. That said, the page tables
 627 * will be allocated at the end of the memory, and we map the
 628 * memory in top-down.
 629 */
 630static void __init memory_map_top_down(unsigned long map_start,
 631				       unsigned long map_end)
 632{
 633	unsigned long real_end, last_start;
 634	unsigned long step_size;
 635	unsigned long addr;
 636	unsigned long mapped_ram_size = 0;
 
 637
 638	/*
 639	 * Systems that have many reserved areas near top of the memory,
 640	 * e.g. QEMU with less than 1G RAM and EFI enabled, or Xen, will
 641	 * require lots of 4K mappings which may exhaust pgt_buf.
 642	 * Start with top-most PMD_SIZE range aligned at PMD_SIZE to ensure
 643	 * there is enough mapped memory that can be allocated from
 644	 * memblock.
 645	 */
 646	addr = memblock_phys_alloc_range(PMD_SIZE, PMD_SIZE, map_start,
 647					 map_end);
 648	memblock_phys_free(addr, PMD_SIZE);
 649	real_end = addr + PMD_SIZE;
 650
 651	/* step_size need to be small so pgt_buf from BRK could cover it */
 652	step_size = PMD_SIZE;
 653	max_pfn_mapped = 0; /* will get exact value next */
 654	min_pfn_mapped = real_end >> PAGE_SHIFT;
 655	last_start = real_end;
 656
 657	/*
 658	 * We start from the top (end of memory) and go to the bottom.
 659	 * The memblock_find_in_range() gets us a block of RAM from the
 660	 * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
 661	 * for page table.
 662	 */
 663	while (last_start > map_start) {
 664		unsigned long start;
 665
 666		if (last_start > step_size) {
 667			start = round_down(last_start - 1, step_size);
 668			if (start < map_start)
 669				start = map_start;
 670		} else
 671			start = map_start;
 672		mapped_ram_size += init_range_memory_mapping(start,
 673							last_start);
 674		last_start = start;
 675		min_pfn_mapped = last_start >> PAGE_SHIFT;
 676		if (mapped_ram_size >= step_size)
 
 677			step_size = get_new_step_size(step_size);
 
 678	}
 679
 680	if (real_end < map_end)
 681		init_range_memory_mapping(real_end, map_end);
 682}
 683
 684/**
 685 * memory_map_bottom_up - Map [map_start, map_end) bottom up
 686 * @map_start: start address of the target memory range
 687 * @map_end: end address of the target memory range
 688 *
 689 * This function will setup direct mapping for memory range
 690 * [map_start, map_end) in bottom-up. Since we have limited the
 691 * bottom-up allocation above the kernel, the page tables will
 692 * be allocated just above the kernel and we map the memory
 693 * in [map_start, map_end) in bottom-up.
 694 */
 695static void __init memory_map_bottom_up(unsigned long map_start,
 696					unsigned long map_end)
 697{
 698	unsigned long next, start;
 699	unsigned long mapped_ram_size = 0;
 700	/* step_size need to be small so pgt_buf from BRK could cover it */
 701	unsigned long step_size = PMD_SIZE;
 702
 703	start = map_start;
 704	min_pfn_mapped = start >> PAGE_SHIFT;
 705
 706	/*
 707	 * We start from the bottom (@map_start) and go to the top (@map_end).
 708	 * The memblock_find_in_range() gets us a block of RAM from the
 709	 * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
 710	 * for page table.
 711	 */
 712	while (start < map_end) {
 713		if (step_size && map_end - start > step_size) {
 714			next = round_up(start + 1, step_size);
 715			if (next > map_end)
 716				next = map_end;
 717		} else {
 718			next = map_end;
 719		}
 720
 721		mapped_ram_size += init_range_memory_mapping(start, next);
 722		start = next;
 723
 724		if (mapped_ram_size >= step_size)
 725			step_size = get_new_step_size(step_size);
 
 726	}
 727}
 728
 729/*
 730 * The real mode trampoline, which is required for bootstrapping CPUs
 731 * occupies only a small area under the low 1MB.  See reserve_real_mode()
 732 * for details.
 733 *
 734 * If KASLR is disabled the first PGD entry of the direct mapping is copied
 735 * to map the real mode trampoline.
 736 *
 737 * If KASLR is enabled, copy only the PUD which covers the low 1MB
 738 * area. This limits the randomization granularity to 1GB for both 4-level
 739 * and 5-level paging.
 740 */
 741static void __init init_trampoline(void)
 742{
 743#ifdef CONFIG_X86_64
 744	/*
 745	 * The code below will alias kernel page-tables in the user-range of the
 746	 * address space, including the Global bit. So global TLB entries will
 747	 * be created when using the trampoline page-table.
 748	 */
 749	if (!kaslr_memory_enabled())
 750		trampoline_pgd_entry = init_top_pgt[pgd_index(__PAGE_OFFSET)];
 751	else
 752		init_trampoline_kaslr();
 753#endif
 754}
 755
 756void __init init_mem_mapping(void)
 757{
 758	unsigned long end;
 759
 760	pti_check_boottime_disable();
 761	probe_page_size_mask();
 762	setup_pcid();
 763
 764#ifdef CONFIG_X86_64
 765	end = max_pfn << PAGE_SHIFT;
 766#else
 767	end = max_low_pfn << PAGE_SHIFT;
 768#endif
 769
 770	/* the ISA range is always mapped regardless of memory holes */
 771	init_memory_mapping(0, ISA_END_ADDRESS, PAGE_KERNEL);
 772
 773	/* Init the trampoline, possibly with KASLR memory offset */
 774	init_trampoline();
 775
 776	/*
 777	 * If the allocation is in bottom-up direction, we setup direct mapping
 778	 * in bottom-up, otherwise we setup direct mapping in top-down.
 779	 */
 780	if (memblock_bottom_up()) {
 781		unsigned long kernel_end = __pa_symbol(_end);
 782
 783		/*
 784		 * we need two separate calls here. This is because we want to
 785		 * allocate page tables above the kernel. So we first map
 786		 * [kernel_end, end) to make memory above the kernel be mapped
 787		 * as soon as possible. And then use page tables allocated above
 788		 * the kernel to map [ISA_END_ADDRESS, kernel_end).
 789		 */
 790		memory_map_bottom_up(kernel_end, end);
 791		memory_map_bottom_up(ISA_END_ADDRESS, kernel_end);
 792	} else {
 793		memory_map_top_down(ISA_END_ADDRESS, end);
 794	}
 795
 796#ifdef CONFIG_X86_64
 797	if (max_pfn > max_low_pfn) {
 798		/* can we preserve max_low_pfn ?*/
 799		max_low_pfn = max_pfn;
 800	}
 801#else
 802	early_ioremap_page_table_range_init();
 803#endif
 804
 805	load_cr3(swapper_pg_dir);
 806	__flush_tlb_all();
 807
 808	x86_init.hyper.init_mem_mapping();
 809
 810	early_memtest(0, max_pfn_mapped << PAGE_SHIFT);
 811}
 812
 813/*
 814 * Initialize an mm_struct to be used during poking and a pointer to be used
 815 * during patching.
 816 */
 817void __init poking_init(void)
 818{
 819	spinlock_t *ptl;
 820	pte_t *ptep;
 821
 822	poking_mm = mm_alloc();
 823	BUG_ON(!poking_mm);
 824
 825	/* Xen PV guests need the PGD to be pinned. */
 826	paravirt_enter_mmap(poking_mm);
 827
 828	/*
 829	 * Randomize the poking address, but make sure that the following page
 830	 * will be mapped at the same PMD. We need 2 pages, so find space for 3,
 831	 * and adjust the address if the PMD ends after the first one.
 832	 */
 833	poking_addr = TASK_UNMAPPED_BASE;
 834	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE))
 835		poking_addr += (kaslr_get_random_long("Poking") & PAGE_MASK) %
 836			(TASK_SIZE - TASK_UNMAPPED_BASE - 3 * PAGE_SIZE);
 837
 838	if (((poking_addr + PAGE_SIZE) & ~PMD_MASK) == 0)
 839		poking_addr += PAGE_SIZE;
 840
 841	/*
 842	 * We need to trigger the allocation of the page-tables that will be
 843	 * needed for poking now. Later, poking may be performed in an atomic
 844	 * section, which might cause allocation to fail.
 845	 */
 846	ptep = get_locked_pte(poking_mm, poking_addr, &ptl);
 847	BUG_ON(!ptep);
 848	pte_unmap_unlock(ptep, ptl);
 849}
 850
 851/*
 852 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 853 * is valid. The argument is a physical page number.
 854 *
 855 * On x86, access has to be given to the first megabyte of RAM because that
 856 * area traditionally contains BIOS code and data regions used by X, dosemu,
 857 * and similar apps. Since they map the entire memory range, the whole range
 858 * must be allowed (for mapping), but any areas that would otherwise be
 859 * disallowed are flagged as being "zero filled" instead of rejected.
 860 * Access has to be given to non-kernel-ram areas as well, these contain the
 861 * PCI mmio resources as well as potential bios/acpi data regions.
 862 */
 863int devmem_is_allowed(unsigned long pagenr)
 864{
 865	if (region_intersects(PFN_PHYS(pagenr), PAGE_SIZE,
 866				IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE)
 867			!= REGION_DISJOINT) {
 868		/*
 869		 * For disallowed memory regions in the low 1MB range,
 870		 * request that the page be shown as all zeros.
 871		 */
 872		if (pagenr < 256)
 873			return 2;
 874
 875		return 0;
 876	}
 877
 878	/*
 879	 * This must follow RAM test, since System RAM is considered a
 880	 * restricted resource under CONFIG_STRICT_DEVMEM.
 881	 */
 882	if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) {
 883		/* Low 1MB bypasses iomem restrictions. */
 884		if (pagenr < 256)
 885			return 1;
 886
 887		return 0;
 888	}
 889
 890	return 1;
 891}
 892
 893void free_init_pages(const char *what, unsigned long begin, unsigned long end)
 894{
 895	unsigned long begin_aligned, end_aligned;
 896
 897	/* Make sure boundaries are page aligned */
 898	begin_aligned = PAGE_ALIGN(begin);
 899	end_aligned   = end & PAGE_MASK;
 900
 901	if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
 902		begin = begin_aligned;
 903		end   = end_aligned;
 904	}
 905
 906	if (begin >= end)
 907		return;
 908
 909	/*
 910	 * If debugging page accesses then do not free this memory but
 911	 * mark them not present - any buggy init-section access will
 912	 * create a kernel page fault:
 913	 */
 914	if (debug_pagealloc_enabled()) {
 915		pr_info("debug: unmapping init [mem %#010lx-%#010lx]\n",
 916			begin, end - 1);
 917		/*
 918		 * Inform kmemleak about the hole in the memory since the
 919		 * corresponding pages will be unmapped.
 920		 */
 921		kmemleak_free_part((void *)begin, end - begin);
 922		set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
 923	} else {
 924		/*
 925		 * We just marked the kernel text read only above, now that
 926		 * we are going to free part of that, we need to make that
 927		 * writeable and non-executable first.
 928		 */
 929		set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
 930		set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
 931
 932		free_reserved_area((void *)begin, (void *)end,
 933				   POISON_FREE_INITMEM, what);
 934	}
 935}
 936
 937/*
 938 * begin/end can be in the direct map or the "high kernel mapping"
 939 * used for the kernel image only.  free_init_pages() will do the
 940 * right thing for either kind of address.
 941 */
 942void free_kernel_image_pages(const char *what, void *begin, void *end)
 943{
 944	unsigned long begin_ul = (unsigned long)begin;
 945	unsigned long end_ul = (unsigned long)end;
 946	unsigned long len_pages = (end_ul - begin_ul) >> PAGE_SHIFT;
 947
 948	free_init_pages(what, begin_ul, end_ul);
 949
 950	/*
 951	 * PTI maps some of the kernel into userspace.  For performance,
 952	 * this includes some kernel areas that do not contain secrets.
 953	 * Those areas might be adjacent to the parts of the kernel image
 954	 * being freed, which may contain secrets.  Remove the "high kernel
 955	 * image mapping" for these freed areas, ensuring they are not even
 956	 * potentially vulnerable to Meltdown regardless of the specific
 957	 * optimizations PTI is currently using.
 958	 *
 959	 * The "noalias" prevents unmapping the direct map alias which is
 960	 * needed to access the freed pages.
 961	 *
 962	 * This is only valid for 64bit kernels. 32bit has only one mapping
 963	 * which can't be treated in this way for obvious reasons.
 964	 */
 965	if (IS_ENABLED(CONFIG_X86_64) && cpu_feature_enabled(X86_FEATURE_PTI))
 966		set_memory_np_noalias(begin_ul, len_pages);
 
 
 
 967}
 968
 969void __ref free_initmem(void)
 970{
 971	e820__reallocate_tables();
 972
 973	mem_encrypt_free_decrypted_mem();
 974
 975	free_kernel_image_pages("unused kernel image (initmem)",
 976				&__init_begin, &__init_end);
 977}
 978
 979#ifdef CONFIG_BLK_DEV_INITRD
 980void __init free_initrd_mem(unsigned long start, unsigned long end)
 981{
 
 
 
 
 
 
 
 
 
 982	/*
 983	 * end could be not aligned, and We can not align that,
 984	 * decompressor could be confused by aligned initrd_end
 985	 * We already reserve the end partial page before in
 986	 *   - i386_start_kernel()
 987	 *   - x86_64_start_kernel()
 988	 *   - relocate_initrd()
 989	 * So here We can do PAGE_ALIGN() safely to get partial page to be freed
 990	 */
 991	free_init_pages("initrd", start, PAGE_ALIGN(end));
 992}
 993#endif
 994
 995void __init zone_sizes_init(void)
 996{
 997	unsigned long max_zone_pfns[MAX_NR_ZONES];
 998
 999	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
1000
1001#ifdef CONFIG_ZONE_DMA
1002	max_zone_pfns[ZONE_DMA]		= min(MAX_DMA_PFN, max_low_pfn);
1003#endif
1004#ifdef CONFIG_ZONE_DMA32
1005	max_zone_pfns[ZONE_DMA32]	= min(MAX_DMA32_PFN, max_low_pfn);
1006#endif
1007	max_zone_pfns[ZONE_NORMAL]	= max_low_pfn;
1008#ifdef CONFIG_HIGHMEM
1009	max_zone_pfns[ZONE_HIGHMEM]	= max_pfn;
1010#endif
1011
1012	free_area_init(max_zone_pfns);
1013}
1014
1015__visible DEFINE_PER_CPU_ALIGNED(struct tlb_state, cpu_tlbstate) = {
1016	.loaded_mm = &init_mm,
1017	.next_asid = 1,
1018	.cr4 = ~0UL,	/* fail hard if we screw up cr4 shadow initialization */
1019};
1020
1021#ifdef CONFIG_ADDRESS_MASKING
1022DEFINE_PER_CPU(u64, tlbstate_untag_mask);
1023EXPORT_PER_CPU_SYMBOL(tlbstate_untag_mask);
1024#endif
1025
1026void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
1027{
1028	/* entry 0 MUST be WB (hardwired to speed up translations) */
1029	BUG_ON(!entry && cache != _PAGE_CACHE_MODE_WB);
1030
1031	__cachemode2pte_tbl[cache] = __cm_idx2pte(entry);
1032	__pte2cachemode_tbl[entry] = cache;
1033}
1034
1035#ifdef CONFIG_SWAP
1036unsigned long arch_max_swapfile_size(void)
1037{
1038	unsigned long pages;
1039
1040	pages = generic_max_swapfile_size();
1041
1042	if (boot_cpu_has_bug(X86_BUG_L1TF) && l1tf_mitigation != L1TF_MITIGATION_OFF) {
1043		/* Limit the swap file size to MAX_PA/2 for L1TF workaround */
1044		unsigned long long l1tf_limit = l1tf_pfn_limit();
1045		/*
1046		 * We encode swap offsets also with 3 bits below those for pfn
1047		 * which makes the usable limit higher.
1048		 */
1049#if CONFIG_PGTABLE_LEVELS > 2
1050		l1tf_limit <<= PAGE_SHIFT - SWP_OFFSET_FIRST_BIT;
1051#endif
1052		pages = min_t(unsigned long long, l1tf_limit, pages);
1053	}
1054	return pages;
1055}
1056#endif
1057
1058#ifdef CONFIG_EXECMEM
1059static struct execmem_info execmem_info __ro_after_init;
1060
1061#ifdef CONFIG_ARCH_HAS_EXECMEM_ROX
1062void execmem_fill_trapping_insns(void *ptr, size_t size, bool writeable)
1063{
1064	/* fill memory with INT3 instructions */
1065	if (writeable)
1066		memset(ptr, INT3_INSN_OPCODE, size);
1067	else
1068		text_poke_set(ptr, INT3_INSN_OPCODE, size);
1069}
1070#endif
1071
1072struct execmem_info __init *execmem_arch_setup(void)
1073{
1074	unsigned long start, offset = 0;
1075	enum execmem_range_flags flags;
1076	pgprot_t pgprot;
1077
1078	if (kaslr_enabled())
1079		offset = get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
1080
1081	start = MODULES_VADDR + offset;
1082
1083	if (IS_ENABLED(CONFIG_ARCH_HAS_EXECMEM_ROX) &&
1084	    cpu_feature_enabled(X86_FEATURE_PSE)) {
1085		pgprot = PAGE_KERNEL_ROX;
1086		flags = EXECMEM_KASAN_SHADOW | EXECMEM_ROX_CACHE;
1087	} else {
1088		pgprot = PAGE_KERNEL;
1089		flags = EXECMEM_KASAN_SHADOW;
1090	}
1091
1092	execmem_info = (struct execmem_info){
1093		.ranges = {
1094			[EXECMEM_MODULE_TEXT] = {
1095				.flags	= flags,
1096				.start	= start,
1097				.end	= MODULES_END,
1098				.pgprot	= pgprot,
1099				.alignment = MODULE_ALIGN,
1100			},
1101			[EXECMEM_KPROBES ... EXECMEM_BPF] = {
1102				.flags	= EXECMEM_KASAN_SHADOW,
1103				.start	= start,
1104				.end	= MODULES_END,
1105				.pgprot	= PAGE_KERNEL,
1106				.alignment = MODULE_ALIGN,
1107			},
1108			[EXECMEM_MODULE_DATA] = {
1109				.flags	= EXECMEM_KASAN_SHADOW,
1110				.start	= start,
1111				.end	= MODULES_END,
1112				.pgprot	= PAGE_KERNEL,
1113				.alignment = MODULE_ALIGN,
1114			},
1115		},
1116	};
1117
1118	return &execmem_info;
1119}
1120#endif /* CONFIG_EXECMEM */