cregit-Linux how code gets into the kernel

Release 4.14 arch/x86/mm/init.c

Directory: arch/x86/mm
#include <linux/gfp.h>
#include <linux/initrd.h>
#include <linux/ioport.h>
#include <linux/swap.h>
#include <linux/memblock.h>
#include <linux/bootmem.h>	/* for max_low_pfn */

#include <asm/set_memory.h>
#include <asm/e820/api.h>
#include <asm/init.h>
#include <asm/page.h>
#include <asm/page_types.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/tlbflush.h>
#include <asm/tlb.h>
#include <asm/proto.h>
#include <asm/dma.h>		/* for MAX_DMA_PFN */
#include <asm/microcode.h>
#include <asm/kaslr.h>
#include <asm/hypervisor.h>
#include <asm/cpufeature.h>

/*
 * We need to define the tracepoints somewhere, and tlb.c
 * is only compied when SMP=y.
 */

#define CREATE_TRACE_POINTS
#include <trace/events/tlb.h>

#include "mm_internal.h"

/*
 * Tables translating between page_cache_type_t and pte encoding.
 *
 * The default values are defined statically as minimal supported mode;
 * WC and WT fall back to UC-.  pat_init() updates these values to support
 * more cache modes, WC and WT, when it is safe to do so.  See pat_init()
 * for the details.  Note, __early_ioremap() used during early boot-time
 * takes pgprot_t (pte encoding) and does not use these tables.
 *
 *   Index into __cachemode2pte_tbl[] is the cachemode.
 *
 *   Index into __pte2cachemode_tbl[] are the caching attribute bits of the pte
 *   (_PAGE_PWT, _PAGE_PCD, _PAGE_PAT) at index bit positions 0, 1, 2.
 */

uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM] = {
	[_PAGE_CACHE_MODE_WB      ]	= 0         | 0        ,
	[_PAGE_CACHE_MODE_WC      ]	= 0         | _PAGE_PCD,
	[_PAGE_CACHE_MODE_UC_MINUS]	= 0         | _PAGE_PCD,
	[_PAGE_CACHE_MODE_UC      ]	= _PAGE_PWT | _PAGE_PCD,
	[_PAGE_CACHE_MODE_WT      ]	= 0         | _PAGE_PCD,
	[_PAGE_CACHE_MODE_WP      ]	= 0         | _PAGE_PCD,
};

EXPORT_SYMBOL(__cachemode2pte_tbl);


uint8_t __pte2cachemode_tbl[8] = {
	[__pte2cm_idx( 0        | 0         | 0        )] = _PAGE_CACHE_MODE_WB,
	[__pte2cm_idx(_PAGE_PWT | 0         | 0        )] = _PAGE_CACHE_MODE_UC_MINUS,
	[__pte2cm_idx( 0        | _PAGE_PCD | 0        )] = _PAGE_CACHE_MODE_UC_MINUS,
	[__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | 0        )] = _PAGE_CACHE_MODE_UC,
	[__pte2cm_idx( 0        | 0         | _PAGE_PAT)] = _PAGE_CACHE_MODE_WB,
	[__pte2cm_idx(_PAGE_PWT | 0         | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
	[__pte2cm_idx(0         | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
	[__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC,
};

EXPORT_SYMBOL(__pte2cachemode_tbl);


static unsigned long __initdata pgt_buf_start;

static unsigned long __initdata pgt_buf_end;

static unsigned long __initdata pgt_buf_top;


static unsigned long min_pfn_mapped;


static bool __initdata can_use_brk_pgt = true;

/*
 * Pages returned are already directly mapped.
 *
 * Changing that is likely to break Xen, see commit:
 *
 *    279b706 x86,xen: introduce x86_init.mapping.pagetable_reserve
 *
 * for detailed information.
 */



__ref void *alloc_low_pages(unsigned int num)
{
	unsigned long pfn;
	int i;

	if (after_bootmem) {
		unsigned int order;

		order = get_order((unsigned long)num << PAGE_SHIFT);
		return (void *)__get_free_pages(GFP_ATOMIC | __GFP_NOTRACK |
						__GFP_ZERO, order);
	}

	if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) {
		unsigned long ret;
		if (min_pfn_mapped >= max_pfn_mapped)
			panic("alloc_low_pages: ran out of memory");
		ret = memblock_find_in_range(min_pfn_mapped << PAGE_SHIFT,
					max_pfn_mapped << PAGE_SHIFT,
					PAGE_SIZE * num , PAGE_SIZE);
		if (!ret)
			panic("alloc_low_pages: can not alloc memory");
		memblock_reserve(ret, PAGE_SIZE * num);
		pfn = ret >> PAGE_SHIFT;
	} else {
		pfn = pgt_buf_end;
		pgt_buf_end += num;
		printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
			pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
	}

	for (i = 0; i < num; i++) {
		void *adr;

		adr = __va((pfn + i) << PAGE_SHIFT);
		clear_page(adr);
	}

	return __va(pfn << PAGE_SHIFT);
}


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/*
 * By default need 3 4k for initial PMD_SIZE,  3 4k for 0-ISA_END_ADDRESS.
 * With KASLR memory randomization, depending on the machine e820 memory
 * and the PUD alignment. We may need twice more pages when KASLR memory
 * randomization is enabled.
 */
#ifndef CONFIG_RANDOMIZE_MEMORY

#define INIT_PGD_PAGE_COUNT      6
#else

#define INIT_PGD_PAGE_COUNT      12
#endif

#define INIT_PGT_BUF_SIZE	(INIT_PGD_PAGE_COUNT * PAGE_SIZE)
RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE);



void  __init early_alloc_pgt_buf(void)
{
	unsigned long tables = INIT_PGT_BUF_SIZE;
	phys_addr_t base;

	base = __pa(extend_brk(tables, PAGE_SIZE));

	pgt_buf_start = base >> PAGE_SHIFT;
	pgt_buf_end = pgt_buf_start;
	pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);
}


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int after_bootmem;

early_param_on_off("gbpages", "nogbpages", direct_gbpages, CONFIG_X86_DIRECT_GBPAGES);


struct map_range {
	
unsigned long start;
	
unsigned long end;
	
unsigned page_size_mask;
};


static int page_size_mask;




static void __init probe_page_size_mask(void)
{
	/*
         * For CONFIG_KMEMCHECK or pagealloc debugging, identity mapping will
         * use small pages.
         * This will simplify cpa(), which otherwise needs to support splitting
         * large pages into small in interrupt context, etc.
         */
	if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled() && !IS_ENABLED(CONFIG_KMEMCHECK))
		page_size_mask |= 1 << PG_LEVEL_2M;
	else
		direct_gbpages = 0;

	/* Enable PSE if available */
	if (boot_cpu_has(X86_FEATURE_PSE))
		cr4_set_bits_and_update_boot(X86_CR4_PSE);

	/* Enable PGE if available */
	if (boot_cpu_has(X86_FEATURE_PGE)) {
		cr4_set_bits_and_update_boot(X86_CR4_PGE);
		__supported_pte_mask |= _PAGE_GLOBAL;
	} else
		__supported_pte_mask &= ~_PAGE_GLOBAL;

	/* Enable 1 GB linear kernel mappings if available: */
	if (direct_gbpages && boot_cpu_has(X86_FEATURE_GBPAGES)) {
		printk(KERN_INFO "Using GB pages for direct mapping\n");
		page_size_mask |= 1 << PG_LEVEL_1G;
	} else {
		direct_gbpages = 0;
	}
}


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Ingo Molnar2725.23%110.00%


Borislav Petkov1614.95%330.00%


Vlastimil Babka1110.28%110.00%


Jan Beulich65.61%110.00%


Christian Bornträger54.67%110.00%


Andrew Lutomirski21.87%110.00%


Total107100.00%10100.00%






static void setup_pcid(void)
{
#ifdef CONFIG_X86_64
	if (boot_cpu_has(X86_FEATURE_PCID)) {
		if (boot_cpu_has(X86_FEATURE_PGE)) {
			/*
                         * This can't be cr4_set_bits_and_update_boot() --
                         * the trampoline code can't handle CR4.PCIDE and
                         * it wouldn't do any good anyway.  Despite the name,
                         * cr4_set_bits_and_update_boot() doesn't actually
                         * cause the bits in question to remain set all the
                         * way through the secondary boot asm.
                         *
                         * Instead, we brute-force it and set CR4.PCIDE
                         * manually in start_secondary().
                         */
			cr4_set_bits(X86_CR4_PCIDE);
		} else {
			/*
                         * flush_tlb_all(), as currently implemented, won't
                         * work if PCID is on but PGE is not.  Since that
                         * combination doesn't exist on real hardware, there's
                         * no reason to try to fully support it, but it's
                         * polite to avoid corrupting data if we're on
                         * an improperly configured VM.
                         */
			setup_clear_cpu_cap(X86_FEATURE_PCID);
		}
	}
#endif
}


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#ifdef CONFIG_X86_32

#define NR_RANGE_MR 3
#else /* CONFIG_X86_64 */

#define NR_RANGE_MR 5
#endif




static int __meminit save_mr(struct map_range *mr, int nr_range,
			     unsigned long start_pfn, unsigned long end_pfn,
			     unsigned long page_size_mask)
{
	if (start_pfn < end_pfn) {
		if (nr_range >= NR_RANGE_MR)
			panic("run out of range for init_memory_mapping\n");
		mr[nr_range].start = start_pfn<<PAGE_SHIFT;
		mr[nr_range].end   = end_pfn<<PAGE_SHIFT;
		mr[nr_range].page_size_mask = page_size_mask;
		nr_range++;
	}

	return nr_range;
}


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Total83100.00%3100.00%



/*
 * adjust the page_size_mask for small range to go with
 *      big page size instead small one if nearby are ram too.
 */



static void __ref adjust_range_page_size_mask(struct map_range *mr,
							 int nr_range)
{
	int i;

	for (i = 0; i < nr_range; i++) {
		if ((page_size_mask & (1<<PG_LEVEL_2M)) &&
		    !(mr[i].page_size_mask & (1<<PG_LEVEL_2M))) {
			unsigned long start = round_down(mr[i].start, PMD_SIZE);
			unsigned long end = round_up(mr[i].end, PMD_SIZE);

#ifdef CONFIG_X86_32
			if ((end >> PAGE_SHIFT) > max_low_pfn)
				continue;
#endif

			if (memblock_is_region_memory(start, end - start))
				mr[i].page_size_mask |= 1<<PG_LEVEL_2M;
		}
		if ((page_size_mask & (1<<PG_LEVEL_1G)) &&
		    !(mr[i].page_size_mask & (1<<PG_LEVEL_1G))) {
			unsigned long start = round_down(mr[i].start, PUD_SIZE);
			unsigned long end = round_up(mr[i].end, PUD_SIZE);

			if (memblock_is_region_memory(start, end - start))
				mr[i].page_size_mask |= 1<<PG_LEVEL_1G;
		}
	}
}


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static const char *page_size_string(struct map_range *mr)
{
	static const char str_1g[] = "1G";
	static const char str_2m[] = "2M";
	static const char str_4m[] = "4M";
	static const char str_4k[] = "4k";

	if (mr->page_size_mask & (1<<PG_LEVEL_1G))
		return str_1g;
	/*
         * 32-bit without PAE has a 4M large page size.
         * PG_LEVEL_2M is misnamed, but we can at least
         * print out the right size in the string.
         */
	if (IS_ENABLED(CONFIG_X86_32) &&
	    !IS_ENABLED(CONFIG_X86_PAE) &&
	    mr->page_size_mask & (1<<PG_LEVEL_2M))
		return str_4m;

	if (mr->page_size_mask & (1<<PG_LEVEL_2M))
		return str_2m;

	return str_4k;
}


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static int __meminit split_mem_range(struct map_range *mr, int nr_range,
				     unsigned long start,
				     unsigned long end)
{
	unsigned long start_pfn, end_pfn, limit_pfn;
	unsigned long pfn;
	int i;

	limit_pfn = PFN_DOWN(end);

	/* head if not big page alignment ? */
	pfn = start_pfn = PFN_DOWN(start);
#ifdef CONFIG_X86_32
	/*
         * Don't use a large page for the first 2/4MB of memory
         * because there are often fixed size MTRRs in there
         * and overlapping MTRRs into large pages can cause
         * slowdowns.
         */
	if (pfn == 0)
		end_pfn = PFN_DOWN(PMD_SIZE);
	else
		end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
#else /* CONFIG_X86_64 */
	end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
#endif
	if (end_pfn > limit_pfn)
		end_pfn = limit_pfn;
	if (start_pfn < end_pfn) {
		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
		pfn = end_pfn;
	}

	/* big page (2M) range */
	start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
#ifdef CONFIG_X86_32
	end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
#else /* CONFIG_X86_64 */
	end_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
	if (end_pfn > round_down(limit_pfn, PFN_DOWN(PMD_SIZE)))
		end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
#endif

	if (start_pfn < end_pfn) {
		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
				page_size_mask & (1<<PG_LEVEL_2M));
		pfn = end_pfn;
	}

#ifdef CONFIG_X86_64
	/* big page (1G) range */
	start_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
	end_pfn = round_down(limit_pfn, PFN_DOWN(PUD_SIZE));
	if (start_pfn < end_pfn) {
		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
				page_size_mask &
				 ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
		pfn = end_pfn;
	}

	/* tail is not big page (1G) alignment */
	start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
	end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
	if (start_pfn < end_pfn) {
		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
				page_size_mask & (1<<PG_LEVEL_2M));
		pfn = end_pfn;
	}
#endif

	/* tail is not big page (2M) alignment */
	start_pfn = pfn;
	end_pfn = limit_pfn;
	nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);

	if (!after_bootmem)
		adjust_range_page_size_mask(mr, nr_range);

	/* try to merge same page size and continuous */
	for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
		unsigned long old_start;
		if (mr[i].end != mr[i+1].start ||
		    mr[i].page_size_mask != mr[i+1].page_size_mask)
			continue;
		/* move it */
		old_start = mr[i].start;
		memmove(&mr[i], &mr[i+1],
			(nr_range - 1 - i) * sizeof(struct map_range));
		mr[i--].start = old_start;
		nr_range--;
	}

	for (i = 0; i < nr_range; i++)
		pr_debug(" [mem %#010lx-%#010lx] page %s\n",
				mr[i].start, mr[i].end - 1,
				page_size_string(&mr[i]));

	return nr_range;
}


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Dave Hansen30.53%17.69%


Dan J Williams10.18%17.69%


Total569100.00%13100.00%




struct range pfn_mapped[E820_MAX_ENTRIES];

int nr_pfn_mapped;




static void add_pfn_range_mapped(unsigned long start_pfn, unsigned long end_pfn)
{
	nr_pfn_mapped = add_range_with_merge(pfn_mapped, E820_MAX_ENTRIES,
					     nr_pfn_mapped, start_pfn, end_pfn);
	nr_pfn_mapped = clean_sort_range(pfn_mapped, E820_MAX_ENTRIES);

	max_pfn_mapped = max(max_pfn_mapped, end_pfn);

	if (start_pfn < (1UL<<(32-PAGE_SHIFT)))
		max_low_pfn_mapped = max(max_low_pfn_mapped,
					 min(end_pfn, 1UL<<(32-PAGE_SHIFT)));
}


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bool pfn_range_is_mapped(unsigned long start_pfn, unsigned long end_pfn)
{
	int i;

	for (i = 0; i < nr_pfn_mapped; i++)
		if ((start_pfn >= pfn_mapped[i].start) &&
		    (end_pfn <= pfn_mapped[i].end))
			return true;

	return false;
}


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/*
 * Setup the direct mapping of the physical memory at PAGE_OFFSET.
 * This runs before bootmem is initialized and gets pages directly from
 * the physical memory. To access them they are temporarily mapped.
 */



unsigned long __ref init_memory_mapping(unsigned long start,
					       unsigned long end)
{
	struct map_range mr[NR_RANGE_MR];
	unsigned long ret = 0;
	int nr_range, i;

	pr_debug("init_memory_mapping: [mem %#010lx-%#010lx]\n",
	       start, end - 1);

	memset(mr, 0, sizeof(mr));
	nr_range = split_mem_range(mr, 0, start, end);

	for (i = 0; i < nr_range; i++)
		ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
						   mr[i].page_size_mask);

	add_pfn_range_mapped(start >> PAGE_SHIFT, ret >> PAGE_SHIFT);

	return ret >> PAGE_SHIFT;
}


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Jacob Shin118.87%120.00%


Dan J Williams10.81%120.00%


Fabian Frederick10.81%120.00%


Total124100.00%5100.00%



/*
 * We need to iterate through the E820 memory map and create direct mappings
 * for only E820_TYPE_RAM and E820_KERN_RESERVED regions. We cannot simply
 * create direct mappings for all pfns from [0 to max_low_pfn) and
 * [4GB to max_pfn) because of possible memory holes in high addresses
 * that cannot be marked as UC by fixed/variable range MTRRs.
 * Depending on the alignment of E820 ranges, this may possibly result
 * in using smaller size (i.e. 4K instead of 2M or 1G) page tables.
 *
 * init_mem_mapping() calls init_range_memory_mapping() with big range.
 * That range would have hole in the middle or ends, and only ram parts
 * will be mapped in init_range_memory_mapping().
 */



static unsigned long __init init_range_memory_mapping(
					   unsigned long r_start,
					   unsigned long r_end)
{
	unsigned long start_pfn, end_pfn;
	unsigned long mapped_ram_size = 0;
	int i;

	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
		u64 start = clamp_val(PFN_PHYS(start_pfn), r_start, r_end);
		u64 end = clamp_val(PFN_PHYS(end_pfn), r_start, r_end);
		if (start >= end)
			continue;

		/*
                 * if it is overlapping with brk pgt, we need to
                 * alloc pgt buf from memblock instead.
                 */
		can_use_brk_pgt = max(start, (u64)pgt_buf_end<<PAGE_SHIFT) >=
				    min(end, (u64)pgt_buf_top<<PAGE_SHIFT);
		init_memory_mapping(start, end);
		mapped_ram_size += end - start;
		can_use_brk_pgt = true;
	}

	return mapped_ram_size;
}


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static unsigned long __init get_new_step_size(unsigned long step_size)
{
	/*
         * Initial mapped size is PMD_SIZE (2M).
         * We can not set step_size to be PUD_SIZE (1G) yet.
         * In worse case, when we cross the 1G boundary, and
         * PG_LEVEL_2M is not set, we will need 1+1+512 pages (2M + 8k)
         * to map 1G range with PTE. Hence we use one less than the
         * difference of page table level shifts.
         *
         * Don't need to worry about overflow in the top-down case, on 32bit,
         * when step_size is 0, round_down() returns 0 for start, and that
         * turns it into 0x100000000ULL.
         * In the bottom-up case, round_up(x, 0) returns 0 though too, which
         * needs to be taken into consideration by the code below.
         */
	return step_size << (PMD_SHIFT - PAGE_SHIFT - 1);
}


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/**
 * memory_map_top_down - Map [map_start, map_end) top down
 * @map_start: start address of the target memory range
 * @map_end: end address of the target memory range
 *
 * This function will setup direct mapping for memory range
 * [map_start, map_end) in top-down. That said, the page tables
 * will be allocated at the end of the memory, and we map the
 * memory in top-down.
 */



static void __init memory_map_top_down(unsigned long map_start,
				       unsigned long map_end)
{
	unsigned long real_end, start, last_start;
	unsigned long step_size;
	unsigned long addr;
	unsigned long mapped_ram_size = 0;

	/* xen has big range in reserved near end of ram, skip it at first.*/
	addr = memblock_find_in_range(map_start, map_end, PMD_SIZE, PMD_SIZE);
	real_end = addr + PMD_SIZE;

	/* step_size need to be small so pgt_buf from BRK could cover it */
	step_size = PMD_SIZE;
	max_pfn_mapped = 0; /* will get exact value next */
	min_pfn_mapped = real_end >> PAGE_SHIFT;
	last_start = start = real_end;

	/*
         * We start from the top (end of memory) and go to the bottom.
         * The memblock_find_in_range() gets us a block of RAM from the
         * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
         * for page table.
         */
	while (last_start > map_start) {
		if (last_start > step_size) {
			start = round_down(last_start - 1, step_size);
			if (start < map_start)
				start = map_start;
		} else
			start = map_start;
		mapped_ram_size += init_range_memory_mapping(start,
							last_start);
		last_start = start;
		min_pfn_mapped = last_start >> PAGE_SHIFT;
		if (mapped_ram_size >= step_size)
			step_size = get_new_step_size(step_size);
	}

	if (real_end < map_end)
		init_range_memory_mapping(real_end, map_end);
}


Contributors
PersonTokensPropCommitsCommitProp
Yinghai Lu14083.83%763.64%


Tang Chen2011.98%19.09%


Jan Beulich42.40%19.09%


Jacob Shin21.20%19.09%


Zhang Yanfei10.60%19.09%


Total167100.00%11100.00%



/**
 * memory_map_bottom_up - Map [map_start, map_end) bottom up
 * @map_start: start address of the target memory range
 * @map_end: end address of the target memory range
 *
 * This function will setup direct mapping for memory range
 * [map_start, map_end) in bottom-up. Since we have limited the
 * bottom-up allocation above the kernel, the page tables will
 * be allocated just above the kernel and we map the memory
 * in [map_start, map_end) in bottom-up.
 */



static void __init memory_map_bottom_up(unsigned long map_start,
					unsigned long map_end)
{
	unsigned long next, start;
	unsigned long mapped_ram_size = 0;
	/* step_size need to be small so pgt_buf from BRK could cover it */
	unsigned long step_size = PMD_SIZE;

	start = map_start;
	min_pfn_mapped = start >> PAGE_SHIFT;

	/*
         * We start from the bottom (@map_start) and go to the top (@map_end).
         * The memblock_find_in_range() gets us a block of RAM from the
         * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
         * for page table.
         */
	while (start < map_end) {
		if (step_size && map_end - start > step_size) {
			next = round_up(start + 1, step_size);
			if (next > map_end)
				next = map_end;
		} else {
			next = map_end;
		}

		mapped_ram_size += init_range_memory_mapping(start, next);
		start = next;

		if (mapped_ram_size >= step_size)
			step_size = get_new_step_size(step_size);
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Tang Chen11193.28%150.00%


Jan Beulich86.72%150.00%


Total119100.00%2100.00%






void __init init_mem_mapping(void)
{
	unsigned long end;

	probe_page_size_mask();
	setup_pcid();

#ifdef CONFIG_X86_64
	end = max_pfn << PAGE_SHIFT;
#else
	end = max_low_pfn << PAGE_SHIFT;
#endif

	/* the ISA range is always mapped regardless of memory holes */
	init_memory_mapping(0, ISA_END_ADDRESS);

	/* Init the trampoline, possibly with KASLR memory offset */
	init_trampoline();

	/*
         * If the allocation is in bottom-up direction, we setup direct mapping
         * in bottom-up, otherwise we setup direct mapping in top-down.
         */
	if (memblock_bottom_up()) {
		unsigned long kernel_end = __pa_symbol(_end);

		/*
                 * we need two separate calls here. This is because we want to
                 * allocate page tables above the kernel. So we first map
                 * [kernel_end, end) to make memory above the kernel be mapped
                 * as soon as possible. And then use page tables allocated above
                 * the kernel to map [ISA_END_ADDRESS, kernel_end).
                 */
		memory_map_bottom_up(kernel_end, end);
		memory_map_bottom_up(ISA_END_ADDRESS, kernel_end);
	} else {
		memory_map_top_down(ISA_END_ADDRESS, end);
	}

#ifdef CONFIG_X86_64
	if (max_pfn > max_low_pfn) {
		/* can we preseve max_low_pfn ?*/
		max_low_pfn = max_pfn;
	}
#else
	early_ioremap_page_table_range_init();
#endif

	load_cr3(swapper_pg_dir);
	__flush_tlb_all();

	hypervisor_init_mem_mapping();

	early_memtest(0, max_pfn_mapped << PAGE_SHIFT);
}


Contributors
PersonTokensPropCommitsCommitProp
Tang Chen8059.70%220.00%


Yinghai Lu4231.34%440.00%


Thomas Garnier42.99%110.00%


Juergen Gross32.24%110.00%


Andrew Lutomirski32.24%110.00%


H. Peter Anvin21.49%110.00%


Total134100.00%10100.00%



/*
 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 * is valid. The argument is a physical page number.
 *
 * On x86, access has to be given to the first megabyte of RAM because that
 * area traditionally contains BIOS code and data regions used by X, dosemu,
 * and similar apps. Since they map the entire memory range, the whole range
 * must be allowed (for mapping), but any areas that would otherwise be
 * disallowed are flagged as being "zero filled" instead of rejected.
 * Access has to be given to non-kernel-ram areas as well, these contain the
 * PCI mmio resources as well as potential bios/acpi data regions.
 */



int devmem_is_allowed(unsigned long pagenr)
{
	if (page_is_ram(pagenr)) {
		/*
                 * For disallowed memory regions in the low 1MB range,
                 * request that the page be shown as all zeros.
                 */
		if (pagenr < 256)
			return 2;

		return 0;
	}

	/*
         * This must follow RAM test, since System RAM is considered a
         * restricted resource under CONFIG_STRICT_IOMEM.
         */
	if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) {
		/* Low 1MB bypasses iomem restrictions. */
		if (pagenr < 256)
			return 1;

		return 0;
	}

	return 1;
}


Contributors
PersonTokensPropCommitsCommitProp
Pekka J Enberg3559.32%133.33%


Kees Cook2338.98%133.33%


T Makphaibulchoke11.69%133.33%


Total59100.00%3100.00%






void free_init_pages(char *what, unsigned long begin, unsigned long end)
{
	unsigned long begin_aligned, end_aligned;

	/* Make sure boundaries are page aligned */
	begin_aligned = PAGE_ALIGN(begin);
	end_aligned   = end & PAGE_MASK;

	if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
		begin = begin_aligned;
		end   = end_aligned;
	}

	if (begin >= end)
		return;

	/*
         * If debugging page accesses then do not free this memory but
         * mark them not present - any buggy init-section access will
         * create a kernel page fault:
         */
	if (debug_pagealloc_enabled()) {
		pr_info("debug: unmapping init [mem %#010lx-%#010lx]\n",
			begin, end - 1);
		set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
	} else {
		/*
                 * We just marked the kernel text read only above, now that
                 * we are going to free part of that, we need to make that
                 * writeable and non-executable first.
                 */
		set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
		set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);

		free_reserved_area((void *)begin, (void *)end,
				   POISON_FREE_INITMEM, what);
	}
}


Contributors
PersonTokensPropCommitsCommitProp
Pekka J Enberg7047.30%114.29%


Yinghai Lu4228.38%114.29%


Matthieu Castet138.78%114.29%


Christian Bornträger128.11%114.29%


Jiang Liu85.41%228.57%


Björn Helgaas32.03%114.29%


Total148100.00%7100.00%






void __ref free_initmem(void)
{
	e820__reallocate_tables();

	free_init_pages("unused kernel",
			(unsigned long)(&__init_begin),
			(unsigned long)(&__init_end));
}


Contributors
PersonTokensPropCommitsCommitProp
Pekka J Enberg2985.29%125.00%


Denys Vlasenko38.82%125.00%


Ingo Molnar12.94%125.00%


Jiang Liu12.94%125.00%


Total34100.00%4100.00%



#ifdef CONFIG_BLK_DEV_INITRD



void __init free_initrd_mem(unsigned long start, unsigned long end)
{
	/*
         * end could be not aligned, and We can not align that,
         * decompresser could be confused by aligned initrd_end
         * We already reserve the end partial page before in
         *   - i386_start_kernel()
         *   - x86_64_start_kernel()
         *   - relocate_initrd()
         * So here We can do PAGE_ALIGN() safely to get partial page to be freed
         */
	free_init_pages("initrd", start, PAGE_ALIGN(end));
}

Contributors
PersonTokensPropCommitsCommitProp
Pekka J Enberg2177.78%125.00%


Yinghai Lu414.81%125.00%


Jiang Liu13.70%125.00%


Jan Beulich13.70%125.00%


Total27100.00%4100.00%



#endif

/*
 * Calculate the precise size of the DMA zone (first 16 MB of RAM),
 * and pass it to the MM layer - to help it set zone watermarks more
 * accurately.
 *
 * Done on 64-bit systems only for the time being, although 32-bit systems
 * might benefit from this as well.
 */



void __init memblock_find_dma_reserve(void)
{
#ifdef CONFIG_X86_64
	u64 nr_pages = 0, nr_free_pages = 0;
	unsigned long start_pfn, end_pfn;
	phys_addr_t start_addr, end_addr;
	int i;
	u64 u;

	/*
         * Iterate over all memory ranges (free and reserved ones alike),
         * to calculate the total number of pages in the first 16 MB of RAM:
         */
	nr_pages = 0;
	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
		start_pfn = min(start_pfn, MAX_DMA_PFN);
		end_pfn   = min(end_pfn,   MAX_DMA_PFN);

		nr_pages += end_pfn - start_pfn;
	}

	/*
         * Iterate over free memory ranges to calculate the number of free
         * pages in the DMA zone, while not counting potential partial
         * pages at the beginning or the end of the range:
         */
	nr_free_pages = 0;
	for_each_free_mem_range(u, NUMA_NO_NODE, MEMBLOCK_NONE, &start_addr, &end_addr, NULL) {
		start_pfn = min_t(unsigned long, PFN_UP(start_addr), MAX_DMA_PFN);
		end_pfn   = min_t(unsigned long, PFN_DOWN(end_addr), MAX_DMA_PFN);

		if (start_pfn < end_pfn)
			nr_free_pages += end_pfn - start_pfn;
	}

	set_dma_reserve(nr_pages - nr_free_pages);
#endif
}


Contributors
PersonTokensPropCommitsCommitProp
Ingo Molnar144100.00%1100.00%


Total144100.00%1100.00%






void __init zone_sizes_init(void)
{
	unsigned long max_zone_pfns[MAX_NR_ZONES];

	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));

#ifdef CONFIG_ZONE_DMA
	max_zone_pfns[ZONE_DMA]		= min(MAX_DMA_PFN, max_low_pfn);
#endif
#ifdef CONFIG_ZONE_DMA32
	max_zone_pfns[ZONE_DMA32]	= min(MAX_DMA32_PFN, max_low_pfn);
#endif
	max_zone_pfns[ZONE_NORMAL]	= max_low_pfn;
#ifdef CONFIG_HIGHMEM
	max_zone_pfns[ZONE_HIGHMEM]	= max_pfn;
#endif

	free_area_init_nodes(max_zone_pfns);
}


Contributors
PersonTokensPropCommitsCommitProp
Pekka J Enberg7588.24%150.00%


Xishi Qiu1011.76%150.00%


Total85100.00%2100.00%



DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
	.loaded_mm = &init_mm,
	.next_asid = 1,
	.cr4 = ~0UL,	/* fail hard if we screw up cr4 shadow initialization */
};

EXPORT_SYMBOL_GPL(cpu_tlbstate);




void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
{
	/* entry 0 MUST be WB (hardwired to speed up translations) */
	BUG_ON(!entry && cache != _PAGE_CACHE_MODE_WB);

	__cachemode2pte_tbl[cache] = __cm_idx2pte(entry);
	__pte2cachemode_tbl[entry] = cache;
}

Contributors
PersonTokensPropCommitsCommitProp
Juergen Gross40100.00%1100.00%


Total40100.00%1100.00%




Overall Contributors
PersonTokensPropCommitsCommitProp
Yinghai Lu163351.47%2829.47%


Pekka J Enberg41112.95%77.37%


Tang Chen2136.71%22.11%


Ingo Molnar2126.68%88.42%


Juergen Gross1875.89%44.21%


Dave Hansen1153.62%22.11%


Jacob Shin1123.53%22.11%


Andrew Lutomirski882.77%55.26%


Jan Beulich300.95%44.21%


Thomas Garnier240.76%33.16%


Kees Cook240.76%11.05%


Borislav Petkov200.63%44.21%


Christian Bornträger170.54%22.11%


Matthieu Castet130.41%11.05%


Vlastimil Babka110.35%11.05%


Xishi Qiu100.32%11.05%


Jiang Liu100.32%22.11%


Luis R. Rodriguez70.22%22.11%


Jaswinder Singh Rajput60.19%22.11%


Stefano Stabellini60.19%22.11%


Denys Vlasenko30.09%11.05%


Tejun Heo30.09%11.05%


Björn Helgaas30.09%11.05%


Fenghua Yu30.09%11.05%


Dan J Williams20.06%11.05%


Zhi Yong Wu20.06%11.05%


Fabian Frederick20.06%11.05%


H. Peter Anvin20.06%11.05%


Laura Abbott10.03%11.05%


T Makphaibulchoke10.03%11.05%


Zhang Yanfei10.03%11.05%


Toshi Kani10.03%11.05%


Total3173100.00%95100.00%


Directory: arch/x86/mm



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