#include <linux/gfp.h>
#include <linux/initrd.h>
#include <linux/ioport.h>
#include <linux/swap.h>
#include <linux/memblock.h>

#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/system.h>
#include <asm/tlbflush.h>
#include <asm/tlb.h>
#include <asm/proto.h>

unsigned long __initdata pgt_buf_start;
unsigned long __meminitdata pgt_buf_end;
unsigned long __meminitdata pgt_buf_top;

int after_bootmem;

int direct_gbpages
#ifdef CONFIG_DIRECT_GBPAGES
                                = 1
#endif
;

static void __init find_early_table_space(unsigned long end, int use_pse,
                                          int use_gbpages)
{
        unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;
        phys_addr_t base;

        puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
        tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);

        if (use_gbpages) {
                unsigned long extra;

                extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
                pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
        } else
                pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;

        tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);

        if (use_pse) {
                unsigned long extra;

                extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
#ifdef CONFIG_X86_32
                extra += PMD_SIZE;
#endif
                ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
        } else
                ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;

        tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);

#ifdef CONFIG_X86_32
        /* for fixmap */
        tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
#endif
        good_end = max_pfn_mapped << PAGE_SHIFT;

        base = memblock_find_in_range(start, good_end, tables, PAGE_SIZE);
        if (base == MEMBLOCK_ERROR)
                panic("Cannot find space for the kernel page tables");

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

        printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
                end, pgt_buf_start << PAGE_SHIFT, pgt_buf_top << PAGE_SHIFT);
}

void __init native_pagetable_reserve(u64 start, u64 end)
{
        memblock_x86_reserve_range(start, end, "PGTABLE");
}

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

#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;
}

/*
 * 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)
{
        unsigned long page_size_mask = 0;
        unsigned long start_pfn, end_pfn;
        unsigned long ret = 0;
        unsigned long pos;

        struct map_range mr[NR_RANGE_MR];
        int nr_range, i;
        int use_pse, use_gbpages;

        printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end);

#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
        /*
         * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
         * This will simplify cpa(), which otherwise needs to support splitting
         * large pages into small in interrupt context, etc.
         */
        use_pse = use_gbpages = 0;
#else
        use_pse = cpu_has_pse;
        use_gbpages = direct_gbpages;
#endif

        /* Enable PSE if available */
        if (cpu_has_pse)
                set_in_cr4(X86_CR4_PSE);

        /* Enable PGE if available */
        if (cpu_has_pge) {
                set_in_cr4(X86_CR4_PGE);
                __supported_pte_mask |= _PAGE_GLOBAL;
        }

        if (use_gbpages)
                page_size_mask |= 1 << PG_LEVEL_1G;
        if (use_pse)
                page_size_mask |= 1 << PG_LEVEL_2M;

        memset(mr, 0, sizeof(mr));
        nr_range = 0;

        /* head if not big page alignment ? */
        start_pfn = start >> PAGE_SHIFT;
        pos = start_pfn << PAGE_SHIFT;
#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 (pos == 0)
                end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
        else
                end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
                                 << (PMD_SHIFT - PAGE_SHIFT);
#else /* CONFIG_X86_64 */
        end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)
                        << (PMD_SHIFT - PAGE_SHIFT);
#endif
        if (end_pfn > (end >> PAGE_SHIFT))
                end_pfn = end >> PAGE_SHIFT;
        if (start_pfn < end_pfn) {
                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
                pos = end_pfn << PAGE_SHIFT;
        }

        /* big page (2M) range */
        start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
                         << (PMD_SHIFT - PAGE_SHIFT);
#ifdef CONFIG_X86_32
        end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
#else /* CONFIG_X86_64 */
        end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
                         << (PUD_SHIFT - PAGE_SHIFT);
        if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)))
                end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT));
#endif

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

#ifdef CONFIG_X86_64
        /* big page (1G) range */
        start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
                         << (PUD_SHIFT - PAGE_SHIFT);
        end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
        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)));
                pos = end_pfn << PAGE_SHIFT;
        }

        /* tail is not big page (1G) alignment */
        start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
                         << (PMD_SHIFT - PAGE_SHIFT);
        end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
        if (start_pfn < end_pfn) {
                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
                                page_size_mask & (1<<PG_LEVEL_2M));
                pos = end_pfn << PAGE_SHIFT;
        }
#endif

        /* tail is not big page (2M) alignment */
        start_pfn = pos>>PAGE_SHIFT;
        end_pfn = end>>PAGE_SHIFT;
        nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);

        /* 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 " %010lx - %010lx page %s\n",
                                mr[i].start, mr[i].end,
                        (mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
                         (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));

        /*
         * Find space for the kernel direct mapping tables.
         *
         * Later we should allocate these tables in the local node of the
         * memory mapped. Unfortunately this is done currently before the
         * nodes are discovered.
         */
        if (!after_bootmem)
                find_early_table_space(end, use_pse, use_gbpages);

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

#ifdef CONFIG_X86_32
        early_ioremap_page_table_range_init();

        load_cr3(swapper_pg_dir);
#endif

        __flush_tlb_all();

        /*
         * Reserve the kernel pagetable pages we used (pgt_buf_start -
         * pgt_buf_end) and free the other ones (pgt_buf_end - pgt_buf_top)
         * so that they can be reused for other purposes.
         *
         * On native it just means calling memblock_x86_reserve_range, on Xen it
         * also means marking RW the pagetable pages that we allocated before
         * but that haven't been used.
         *
         * In fact on xen we mark RO the whole range pgt_buf_start -
         * pgt_buf_top, because we have to make sure that when
         * init_memory_mapping reaches the pagetable pages area, it maps
         * RO all the pagetable pages, including the ones that are beyond
         * pgt_buf_end at that time.
         */
        if (!after_bootmem && pgt_buf_end > pgt_buf_start)
                x86_init.mapping.pagetable_reserve(PFN_PHYS(pgt_buf_start),
                                PFN_PHYS(pgt_buf_end));

        if (!after_bootmem)
                early_memtest(start, end);

        return ret >> 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 addr;
        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;

        addr = begin;

        /*
         * 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 memory %08lx..%08lx\n",
                begin, end);
        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);

        printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);

        for (; addr < end; addr += PAGE_SIZE) {
                ClearPageReserved(virt_to_page(addr));
                init_page_count(virt_to_page(addr));
                memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
                free_page(addr);
                totalram_pages++;
        }
#endif
}

void free_initmem(void)
{
        free_init_pages("unused kernel memory",
                        (unsigned long)(&__init_begin),
                        (unsigned long)(&__init_end));
}

#ifdef CONFIG_BLK_DEV_INITRD
void 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 memory", start, PAGE_ALIGN(end));
}
#endif