Initial import

1 files changed, 752 insertions, 0 deletions

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
new file mode 100644
index 000000000..f971ac820
--- /dev/null
+++ b/arch/x86/mm/init.c
@@ -0,0 +1,752 @@
+#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/cacheflush.h>
+#include <asm/e820.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>
+
+/*
+ * 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.
+ *
+ * Minimal supported modes are defined statically, they are modified
+ * during bootup if more supported cache modes are available.
+ *
+ *   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      ]	= _PAGE_PWT | 0        ,
+	[_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_WC,
+	[__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_WC,
+	[__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);
+}
+
+/* need 3 4k for initial PMD_SIZE,  3 4k for 0-ISA_END_ADDRESS */
+#define INIT_PGT_BUF_SIZE	(6 * 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);
+}
+
+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)
+{
+#if !defined(CONFIG_DEBUG_PAGEALLOC) && !defined(CONFIG_KMEMCHECK) && !defined(CONFIG_TOI_INCREMENTAL)
+	/*
+	 * For CONFIG_DEBUG_PAGEALLOC or TuxOnIce's incremental image support,
+         * 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 (cpu_has_pse)
+		page_size_mask |= 1 << PG_LEVEL_2M;
+#endif
+
+	/* Enable PSE if available */
+	if (cpu_has_pse)
+		cr4_set_bits_and_update_boot(X86_CR4_PSE);
+
+	/* Enable PGE if available */
+	if (cpu_has_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 && cpu_has_gbpages) {
+		printk(KERN_INFO "Using GB pages for direct mapping\n");
+		page_size_mask |= 1 << PG_LEVEL_1G;
+	} else {
+		direct_gbpages = 0;
+	}
+}
+
+#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;
+}
+
+/*
+ * adjust the page_size_mask for small range to go with
+ *	big page size instead small one if nearby are ram too.
+ */
+static void __init_refok 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;
+		}
+	}
+}
+
+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;
+}
+
+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++)
+		printk(KERN_DEBUG " [mem %#010lx-%#010lx] page %s\n",
+				mr[i].start, mr[i].end - 1,
+				page_size_string(&mr[i]));
+
+	return nr_range;
+}
+
+struct range pfn_mapped[E820_X_MAX];
+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_X_MAX,
+					     nr_pfn_mapped, start_pfn, end_pfn);
+	nr_pfn_mapped = clean_sort_range(pfn_mapped, E820_X_MAX);
+
+	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)));
+}
+
+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;
+}
+
+/*
+ * 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 __init_refok 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_info("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;
+}
+
+/*
+ * We need to iterate through the E820 memory map and create direct mappings
+ * for only E820_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;
+}
+
+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);
+}
+
+/**
+ * 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);
+}
+
+/**
+ * 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);
+	}
+}
+
+void __init init_mem_mapping(void)
+{
+	unsigned long end;
+
+	probe_page_size_mask();
+
+#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);
+
+	/*
+	 * 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();
+
+	early_memtest(0, max_pfn_mapped << PAGE_SHIFT);
+}
+
+/*
+ * 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
+ * contains BIOS code and data regions used by X and dosemu and similar apps.
+ * 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 (pagenr < 256)
+		return 1;
+	if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
+		return 0;
+	if (!page_is_ram(pagenr))
+		return 1;
+	return 0;
+}
+
+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:
+	 */
+#ifdef CONFIG_DEBUG_PAGEALLOC
+	printk(KERN_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);
+#endif
+}
+
+void free_initmem(void)
+{
+	free_init_pages("unused kernel",
+			(unsigned long)(&__init_begin),
+			(unsigned long)(&__init_end));
+}
+
+#ifdef CONFIG_BLK_DEV_INITRD
+void __init free_initrd_mem(unsigned long start, unsigned long end)
+{
+#ifdef CONFIG_MICROCODE_EARLY
+	/*
+	 * Remember, initrd memory may contain microcode or other useful things.
+	 * Before we lose initrd mem, we need to find a place to hold them
+	 * now that normal virtual memory is enabled.
+	 */
+	save_microcode_in_initrd();
+#endif
+
+	/*
+	 * 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));
+}
+#endif
+
+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);
+}
+
+DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
+#ifdef CONFIG_SMP
+	.active_mm = &init_mm,
+	.state = 0,
+#endif
+	.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;
+}