/* 
 * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
 * Licensed under the GPL
 */

#include "linux/stddef.h"
#include "linux/kernel.h"
#include "linux/mm.h"
#include "linux/bootmem.h"
#include "linux/swap.h"
#include "linux/highmem.h"
#include "linux/gfp.h"
#include "asm/page.h"
#include "asm/fixmap.h"
#include "asm/pgalloc.h"
#include "user_util.h"
#include "kern_util.h"
#include "kern.h"
#include "mem_user.h"
#include "uml_uaccess.h"
#include "os.h"

extern char __binary_start;

/* Changed during early boot */
unsigned long *empty_zero_page = NULL;
unsigned long *empty_bad_page = NULL;
pgd_t swapper_pg_dir[PTRS_PER_PGD];
unsigned long highmem;
int kmalloc_ok = 0;

static unsigned long brk_end;

void unmap_physmem(void)
{
        os_unmap_memory((void *) brk_end, uml_reserved - brk_end);
}

static void map_cb(void *unused)
{
        map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
}

#ifdef CONFIG_HIGHMEM
static void setup_highmem(unsigned long highmem_start,
                          unsigned long highmem_len)
{
        struct page *page;
        unsigned long highmem_pfn;
        int i;

        highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
        for(i = 0; i < highmem_len >> PAGE_SHIFT; i++){
                page = &mem_map[highmem_pfn + i];
                ClearPageReserved(page);
                set_bit(PG_highmem, &page->flags);
                set_page_count(page, 1);
                __free_page(page);
        }
}
#endif

void mem_init(void)
{
        unsigned long start;

        max_low_pfn = (high_physmem - uml_physmem) >> PAGE_SHIFT;

        /* clear the zero-page */
        memset((void *) empty_zero_page, 0, PAGE_SIZE);

        /* Map in the area just after the brk now that kmalloc is about
         * to be turned on.
         */
        brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
        map_cb(NULL);
        initial_thread_cb(map_cb, NULL);
        free_bootmem(__pa(brk_end), uml_reserved - brk_end);
        uml_reserved = brk_end;

        /* Fill in any hole at the start of the binary */
        start = (unsigned long) &__binary_start & PAGE_MASK;
        if(uml_physmem != start){
                map_memory(uml_physmem, __pa(uml_physmem), start - uml_physmem,
                           1, 1, 0);
        }

        /* this will put all low memory onto the freelists */
        totalram_pages = free_all_bootmem();
        totalhigh_pages = highmem >> PAGE_SHIFT;
        totalram_pages += totalhigh_pages;
        num_physpages = totalram_pages;
        max_pfn = totalram_pages;
        printk(KERN_INFO "Memory: %luk available\n", 
               (unsigned long) nr_free_pages() << (PAGE_SHIFT-10));
        kmalloc_ok = 1;

#ifdef CONFIG_HIGHMEM
        setup_highmem(end_iomem, highmem);
#endif
}

static void __init fixrange_init(unsigned long start, unsigned long end, 
                                 pgd_t *pgd_base)
{
        pgd_t *pgd;
        pmd_t *pmd;
        pte_t *pte;
        int i, j;
        unsigned long vaddr;

        vaddr = start;
        i = pgd_index(vaddr);
        j = pmd_index(vaddr);
        pgd = pgd_base + i;

        for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
                pmd = (pmd_t *)pgd;
                for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
                        if (pmd_none(*pmd)) {
                                pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
                                set_pmd(pmd, __pmd(_KERNPG_TABLE + 
                                                   (unsigned long) __pa(pte)));
                                if (pte != pte_offset_kernel(pmd, 0))
                                        BUG();
                        }
                        vaddr += PMD_SIZE;
                }
                j = 0;
        }
}

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;

#define kmap_get_fixmap_pte(vaddr)                                      \
        pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
                          (vaddr)), (vaddr))

void __init kmap_init(void)
{
        unsigned long kmap_vstart;

        /* cache the first kmap pte */
        kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
        kmap_pte = kmap_get_fixmap_pte(kmap_vstart);

        kmap_prot = PAGE_KERNEL;
}

static void init_highmem(void)
{
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
        pte_t *pte;
        unsigned long vaddr;

        /*
         * Permanent kmaps:
         */
        vaddr = PKMAP_BASE;
        fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);

        pgd = swapper_pg_dir + pgd_index(vaddr);
        pud = pud_offset(pgd, vaddr);
        pmd = pmd_offset(pud, vaddr);
        pte = pte_offset_kernel(pmd, vaddr);
        pkmap_page_table = pte;

        kmap_init();
}
#endif /* CONFIG_HIGHMEM */

static void __init fixaddr_user_init( void)
{
#if CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
        long size = FIXADDR_USER_END - FIXADDR_USER_START;
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
        pte_t *pte;
        unsigned long paddr, vaddr = FIXADDR_USER_START;

        if (  ! size )
                return;

        fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
        paddr = (unsigned long)alloc_bootmem_low_pages( size);
        memcpy( (void *)paddr, (void *)FIXADDR_USER_START, size);
        paddr = __pa(paddr);
        for ( ; size > 0; size-=PAGE_SIZE, vaddr+=PAGE_SIZE, paddr+=PAGE_SIZE){
                pgd = swapper_pg_dir + pgd_index(vaddr);
                pud = pud_offset(pgd, vaddr);
                pmd = pmd_offset(pud, vaddr);
                pte = pte_offset_kernel(pmd, vaddr);
                pte_set_val( (*pte), paddr, PAGE_READONLY);
        }
#endif
}

void paging_init(void)
{
        unsigned long zones_size[MAX_NR_ZONES], vaddr;
        int i;

        empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
        empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
        for(i=0;i<sizeof(zones_size)/sizeof(zones_size[0]);i++) 
                zones_size[i] = 0;
        zones_size[0] = (end_iomem >> PAGE_SHIFT) - (uml_physmem >> PAGE_SHIFT);
        zones_size[2] = highmem >> PAGE_SHIFT;
        free_area_init(zones_size);

        /*
         * Fixed mappings, only the page table structure has to be
         * created - mappings will be set by set_fixmap():
         */
        vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
        fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);

        fixaddr_user_init();

#ifdef CONFIG_HIGHMEM
        init_highmem();
#endif
}

struct page *arch_validate(struct page *page, int mask, int order)
{
        unsigned long addr, zero = 0;
        int i;

 again:
        if(page == NULL) return(page);
        if(PageHighMem(page)) return(page);

        addr = (unsigned long) page_address(page);
        for(i = 0; i < (1 << order); i++){
                current->thread.fault_addr = (void *) addr;
                if(__do_copy_to_user((void __user *) addr, &zero,
                                     sizeof(zero),
                                     &current->thread.fault_addr,
                                     &current->thread.fault_catcher)){
                        if(!(mask & __GFP_WAIT)) return(NULL);
                        else break;
                }
                addr += PAGE_SIZE;
        }

        if(i == (1 << order)) return(page);
        page = alloc_pages(mask, order);
        goto again;
}

/* This can't do anything because nothing in the kernel image can be freed
 * since it's not in kernel physical memory.
 */

void free_initmem(void)
{
}

#ifdef CONFIG_BLK_DEV_INITRD

void free_initrd_mem(unsigned long start, unsigned long end)
{
        if (start < end)
                printk ("Freeing initrd memory: %ldk freed\n", 
                        (end - start) >> 10);
        for (; start < end; start += PAGE_SIZE) {
                ClearPageReserved(virt_to_page(start));
                set_page_count(virt_to_page(start), 1);
                free_page(start);
                totalram_pages++;
        }
}
        
#endif

void show_mem(void)
{
        int pfn, total = 0, reserved = 0;
        int shared = 0, cached = 0;
        int highmem = 0;
        struct page *page;

        printk("Mem-info:\n");
        show_free_areas();
        printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
        pfn = max_mapnr;
        while(pfn-- > 0) {
                page = pfn_to_page(pfn);
                total++;
                if(PageHighMem(page))
                        highmem++;
                if(PageReserved(page))
                        reserved++;
                else if(PageSwapCache(page))
                        cached++;
                else if(page_count(page))
                        shared += page_count(page) - 1;
        }
        printk("%d pages of RAM\n", total);
        printk("%d pages of HIGHMEM\n", highmem);
        printk("%d reserved pages\n", reserved);
        printk("%d pages shared\n", shared);
        printk("%d pages swap cached\n", cached);
}

/*
 * Allocate and free page tables.
 */

pgd_t *pgd_alloc(struct mm_struct *mm)
{
        pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);

        if (pgd) {
                memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
                memcpy(pgd + USER_PTRS_PER_PGD, 
                       swapper_pg_dir + USER_PTRS_PER_PGD, 
                       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
        }
        return pgd;
}

void pgd_free(pgd_t *pgd)
{
        free_page((unsigned long) pgd);
}

pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
        pte_t *pte;

        pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
        return pte;
}

struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
        struct page *pte;
   
        pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
        return pte;
}

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-file-style: "linux"
 * End:
 */