[deliverable/linux.git] / arch / parisc / mm / init.c

/*
 *  linux/arch/parisc/mm/init.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *  Copyright 1999 SuSE GmbH
 *    changed by Philipp Rumpf
 *  Copyright 1999 Philipp Rumpf (prumpf@tux.org)
 *  Copyright 2004 Randolph Chung (tausq@debian.org)
 *
 */

#include <linux/config.h>

#include <linux/module.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/pci.h>          /* for hppa_dma_ops and pcxl_dma_ops */
#include <linux/initrd.h>
#include <linux/swap.h>
#include <linux/unistd.h>
#include <linux/nodemask.h>     /* for node_online_map */
#include <linux/pagemap.h>      /* for release_pages and page_cache_release */

#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/pdc_chassis.h>
#include <asm/mmzone.h>

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

extern char _text;      /* start of kernel code, defined by linker */
extern int  data_start;
extern char _end;       /* end of BSS, defined by linker */
extern char __init_begin, __init_end;

#ifdef CONFIG_DISCONTIGMEM
struct node_map_data node_data[MAX_NUMNODES] __read_mostly;
bootmem_data_t bmem_data[MAX_NUMNODES] __read_mostly;
unsigned char pfnnid_map[PFNNID_MAP_MAX] __read_mostly;
#endif

static struct resource data_resource = {
        .name   = "Kernel data",
        .flags  = IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource code_resource = {
        .name   = "Kernel code",
        .flags  = IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource pdcdata_resource = {
        .name   = "PDC data (Page Zero)",
        .start  = 0,
        .end    = 0x9ff,
        .flags  = IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource sysram_resources[MAX_PHYSMEM_RANGES] __read_mostly;

/* The following array is initialized from the firmware specific
 * information retrieved in kernel/inventory.c.
 */

physmem_range_t pmem_ranges[MAX_PHYSMEM_RANGES] __read_mostly;
int npmem_ranges __read_mostly;

#ifdef __LP64__
#define MAX_MEM         (~0UL)
#else /* !__LP64__ */
#define MAX_MEM         (3584U*1024U*1024U)
#endif /* !__LP64__ */

static unsigned long mem_limit __read_mostly = MAX_MEM;

static void __init mem_limit_func(void)
{
        char *cp, *end;
        unsigned long limit;
        extern char saved_command_line[];

        /* We need this before __setup() functions are called */

        limit = MAX_MEM;
        for (cp = saved_command_line; *cp; ) {
                if (memcmp(cp, "mem=", 4) == 0) {
                        cp += 4;
                        limit = memparse(cp, &end);
                        if (end != cp)
                                break;
                        cp = end;
                } else {
                        while (*cp != ' ' && *cp)
                                ++cp;
                        while (*cp == ' ')
                                ++cp;
                }
        }

        if (limit < mem_limit)
                mem_limit = limit;
}

#define MAX_GAP (0x40000000UL >> PAGE_SHIFT)

static void __init setup_bootmem(void)
{
        unsigned long bootmap_size;
        unsigned long mem_max;
        unsigned long bootmap_pages;
        unsigned long bootmap_start_pfn;
        unsigned long bootmap_pfn;
#ifndef CONFIG_DISCONTIGMEM
        physmem_range_t pmem_holes[MAX_PHYSMEM_RANGES - 1];
        int npmem_holes;
#endif
        int i, sysram_resource_count;

        disable_sr_hashing(); /* Turn off space register hashing */

        /*
         * Sort the ranges. Since the number of ranges is typically
         * small, and performance is not an issue here, just do
         * a simple insertion sort.
         */

        for (i = 1; i < npmem_ranges; i++) {
                int j;

                for (j = i; j > 0; j--) {
                        unsigned long tmp;

                        if (pmem_ranges[j-1].start_pfn <
                            pmem_ranges[j].start_pfn) {

                                break;
                        }
                        tmp = pmem_ranges[j-1].start_pfn;
                        pmem_ranges[j-1].start_pfn = pmem_ranges[j].start_pfn;
                        pmem_ranges[j].start_pfn = tmp;
                        tmp = pmem_ranges[j-1].pages;
                        pmem_ranges[j-1].pages = pmem_ranges[j].pages;
                        pmem_ranges[j].pages = tmp;
                }
        }

#ifndef CONFIG_DISCONTIGMEM
        /*
         * Throw out ranges that are too far apart (controlled by
         * MAX_GAP).
         */

        for (i = 1; i < npmem_ranges; i++) {
                if (pmem_ranges[i].start_pfn -
                        (pmem_ranges[i-1].start_pfn +
                         pmem_ranges[i-1].pages) > MAX_GAP) {
                        npmem_ranges = i;
                        printk("Large gap in memory detected (%ld pages). "
                               "Consider turning on CONFIG_DISCONTIGMEM\n",
                               pmem_ranges[i].start_pfn -
                               (pmem_ranges[i-1].start_pfn +
                                pmem_ranges[i-1].pages));
                        break;
                }
        }
#endif

        if (npmem_ranges > 1) {

                /* Print the memory ranges */

                printk(KERN_INFO "Memory Ranges:\n");

                for (i = 0; i < npmem_ranges; i++) {
                        unsigned long start;
                        unsigned long size;

                        size = (pmem_ranges[i].pages << PAGE_SHIFT);
                        start = (pmem_ranges[i].start_pfn << PAGE_SHIFT);
                        printk(KERN_INFO "%2d) Start 0x%016lx End 0x%016lx Size %6ld MB\n",
                                i,start, start + (size - 1), size >> 20);
                }
        }

        sysram_resource_count = npmem_ranges;
        for (i = 0; i < sysram_resource_count; i++) {
                struct resource *res = &sysram_resources[i];
                res->name = "System RAM";
                res->start = pmem_ranges[i].start_pfn << PAGE_SHIFT;
                res->end = res->start + (pmem_ranges[i].pages << PAGE_SHIFT)-1;
                res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
                request_resource(&iomem_resource, res);
        }

        /*
         * For 32 bit kernels we limit the amount of memory we can
         * support, in order to preserve enough kernel address space
         * for other purposes. For 64 bit kernels we don't normally
         * limit the memory, but this mechanism can be used to
         * artificially limit the amount of memory (and it is written
         * to work with multiple memory ranges).
         */

        mem_limit_func();       /* check for "mem=" argument */

        mem_max = 0;
        num_physpages = 0;
        for (i = 0; i < npmem_ranges; i++) {
                unsigned long rsize;

                rsize = pmem_ranges[i].pages << PAGE_SHIFT;
                if ((mem_max + rsize) > mem_limit) {
                        printk(KERN_WARNING "Memory truncated to %ld MB\n", mem_limit >> 20);
                        if (mem_max == mem_limit)
                                npmem_ranges = i;
                        else {
                                pmem_ranges[i].pages =   (mem_limit >> PAGE_SHIFT)
                                                       - (mem_max >> PAGE_SHIFT);
                                npmem_ranges = i + 1;
                                mem_max = mem_limit;
                        }
                num_physpages += pmem_ranges[i].pages;
                        break;
                }
            num_physpages += pmem_ranges[i].pages;
                mem_max += rsize;
        }

        printk(KERN_INFO "Total Memory: %ld MB\n",mem_max >> 20);

#ifndef CONFIG_DISCONTIGMEM
        /* Merge the ranges, keeping track of the holes */

        {
                unsigned long end_pfn;
                unsigned long hole_pages;

                npmem_holes = 0;
                end_pfn = pmem_ranges[0].start_pfn + pmem_ranges[0].pages;
                for (i = 1; i < npmem_ranges; i++) {

                        hole_pages = pmem_ranges[i].start_pfn - end_pfn;
                        if (hole_pages) {
                                pmem_holes[npmem_holes].start_pfn = end_pfn;
                                pmem_holes[npmem_holes++].pages = hole_pages;
                                end_pfn += hole_pages;
                        }
                        end_pfn += pmem_ranges[i].pages;
                }

                pmem_ranges[0].pages = end_pfn - pmem_ranges[0].start_pfn;
                npmem_ranges = 1;
        }
#endif

        bootmap_pages = 0;
        for (i = 0; i < npmem_ranges; i++)
                bootmap_pages += bootmem_bootmap_pages(pmem_ranges[i].pages);

        bootmap_start_pfn = PAGE_ALIGN(__pa((unsigned long) &_end)) >> PAGE_SHIFT;

#ifdef CONFIG_DISCONTIGMEM
        for (i = 0; i < MAX_PHYSMEM_RANGES; i++) {
                memset(NODE_DATA(i), 0, sizeof(pg_data_t));
                NODE_DATA(i)->bdata = &bmem_data[i];
        }
        memset(pfnnid_map, 0xff, sizeof(pfnnid_map));

        for (i = 0; i < npmem_ranges; i++)
                node_set_online(i);
#endif

        /*
         * Initialize and free the full range of memory in each range.
         * Note that the only writing these routines do are to the bootmap,
         * and we've made sure to locate the bootmap properly so that they
         * won't be writing over anything important.
         */

        bootmap_pfn = bootmap_start_pfn;
        max_pfn = 0;
        for (i = 0; i < npmem_ranges; i++) {
                unsigned long start_pfn;
                unsigned long npages;

                start_pfn = pmem_ranges[i].start_pfn;
                npages = pmem_ranges[i].pages;

                bootmap_size = init_bootmem_node(NODE_DATA(i),
                                                bootmap_pfn,
                                                start_pfn,
                                                (start_pfn + npages) );
                free_bootmem_node(NODE_DATA(i),
                                  (start_pfn << PAGE_SHIFT),
                                  (npages << PAGE_SHIFT) );
                bootmap_pfn += (bootmap_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
                if ((start_pfn + npages) > max_pfn)
                        max_pfn = start_pfn + npages;
        }

        /* IOMMU is always used to access "high mem" on those boxes
         * that can support enough mem that a PCI device couldn't
         * directly DMA to any physical addresses.
         * ISA DMA support will need to revisit this.
         */
        max_low_pfn = max_pfn;

        if ((bootmap_pfn - bootmap_start_pfn) != bootmap_pages) {
                printk(KERN_WARNING "WARNING! bootmap sizing is messed up!\n");
                BUG();
        }

        /* reserve PAGE0 pdc memory, kernel text/data/bss & bootmap */

#define PDC_CONSOLE_IO_IODC_SIZE 32768

        reserve_bootmem_node(NODE_DATA(0), 0UL,
                        (unsigned long)(PAGE0->mem_free + PDC_CONSOLE_IO_IODC_SIZE));
        reserve_bootmem_node(NODE_DATA(0),__pa((unsigned long)&_text),
                        (unsigned long)(&_end - &_text));
        reserve_bootmem_node(NODE_DATA(0), (bootmap_start_pfn << PAGE_SHIFT),
                        ((bootmap_pfn - bootmap_start_pfn) << PAGE_SHIFT));

#ifndef CONFIG_DISCONTIGMEM

        /* reserve the holes */

        for (i = 0; i < npmem_holes; i++) {
                reserve_bootmem_node(NODE_DATA(0),
                                (pmem_holes[i].start_pfn << PAGE_SHIFT),
                                (pmem_holes[i].pages << PAGE_SHIFT));
        }
#endif

#ifdef CONFIG_BLK_DEV_INITRD
        if (initrd_start) {
                printk(KERN_INFO "initrd: %08lx-%08lx\n", initrd_start, initrd_end);
                if (__pa(initrd_start) < mem_max) {
                        unsigned long initrd_reserve;

                        if (__pa(initrd_end) > mem_max) {
                                initrd_reserve = mem_max - __pa(initrd_start);
                        } else {
                                initrd_reserve = initrd_end - initrd_start;
                        }
                        initrd_below_start_ok = 1;
                        printk(KERN_INFO "initrd: reserving %08lx-%08lx (mem_max %08lx)\n", __pa(initrd_start), __pa(initrd_start) + initrd_reserve, mem_max);

                        reserve_bootmem_node(NODE_DATA(0),__pa(initrd_start), initrd_reserve);
                }
        }
#endif

        data_resource.start =  virt_to_phys(&data_start);
        data_resource.end = virt_to_phys(&_end)-1;
        code_resource.start = virt_to_phys(&_text);
        code_resource.end = virt_to_phys(&data_start)-1;

        /* We don't know which region the kernel will be in, so try
         * all of them.
         */
        for (i = 0; i < sysram_resource_count; i++) {
                struct resource *res = &sysram_resources[i];
                request_resource(res, &code_resource);
                request_resource(res, &data_resource);
        }
        request_resource(&sysram_resources[0], &pdcdata_resource);
}

void free_initmem(void)
{
        /* FIXME: */
#if 0
        printk(KERN_INFO "NOT FREEING INITMEM (%dk)\n",
                        (&__init_end - &__init_begin) >> 10);
        return;
#else
        unsigned long addr;
        
        printk(KERN_INFO "Freeing unused kernel memory: ");

#if 1
        /* Attempt to catch anyone trying to execute code here
         * by filling the page with BRK insns.
         * 
         * If we disable interrupts for all CPUs, then IPI stops working.
         * Kinda breaks the global cache flushing.
         */
        local_irq_disable();

        memset(&__init_begin, 0x00, 
                (unsigned long)&__init_end - (unsigned long)&__init_begin);

        flush_data_cache();
        asm volatile("sync" : : );
        flush_icache_range((unsigned long)&__init_begin, (unsigned long)&__init_end);
        asm volatile("sync" : : );

        local_irq_enable();
#endif
        
        addr = (unsigned long)(&__init_begin);
        for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
                ClearPageReserved(virt_to_page(addr));
                set_page_count(virt_to_page(addr), 1);
                free_page(addr);
                num_physpages++;
                totalram_pages++;
        }

        /* set up a new led state on systems shipped LED State panel */
        pdc_chassis_send_status(PDC_CHASSIS_DIRECT_BCOMPLETE);
        
        printk("%luk freed\n", (unsigned long)(&__init_end - &__init_begin) >> 10);
#endif
}

/*
 * Just an arbitrary offset to serve as a "hole" between mapping areas
 * (between top of physical memory and a potential pcxl dma mapping
 * area, and below the vmalloc mapping area).
 *
 * The current 32K value just means that there will be a 32K "hole"
 * between mapping areas. That means that  any out-of-bounds memory
 * accesses will hopefully be caught. The vmalloc() routines leaves
 * a hole of 4kB between each vmalloced area for the same reason.
 */

 /* Leave room for gateway page expansion */
#if KERNEL_MAP_START < GATEWAY_PAGE_SIZE
#error KERNEL_MAP_START is in gateway reserved region
#endif
#define MAP_START (KERNEL_MAP_START)

#define VM_MAP_OFFSET  (32*1024)
#define SET_MAP_OFFSET(x) ((void *)(((unsigned long)(x) + VM_MAP_OFFSET) \
                                     & ~(VM_MAP_OFFSET-1)))

void *vmalloc_start __read_mostly;
EXPORT_SYMBOL(vmalloc_start);

#ifdef CONFIG_PA11
unsigned long pcxl_dma_start __read_mostly;
#endif

void __init mem_init(void)
{
        high_memory = __va((max_pfn << PAGE_SHIFT));

#ifndef CONFIG_DISCONTIGMEM
        max_mapnr = page_to_pfn(virt_to_page(high_memory - 1)) + 1;
        totalram_pages += free_all_bootmem();
#else
        {
                int i;

                for (i = 0; i < npmem_ranges; i++)
                        totalram_pages += free_all_bootmem_node(NODE_DATA(i));
        }
#endif

        printk(KERN_INFO "Memory: %luk available\n", num_physpages << (PAGE_SHIFT-10));

#ifdef CONFIG_PA11
        if (hppa_dma_ops == &pcxl_dma_ops) {
                pcxl_dma_start = (unsigned long)SET_MAP_OFFSET(MAP_START);
                vmalloc_start = SET_MAP_OFFSET(pcxl_dma_start + PCXL_DMA_MAP_SIZE);
        } else {
                pcxl_dma_start = 0;
                vmalloc_start = SET_MAP_OFFSET(MAP_START);
        }
#else
        vmalloc_start = SET_MAP_OFFSET(MAP_START);
#endif

}

int do_check_pgt_cache(int low, int high)
{
        return 0;
}

unsigned long *empty_zero_page __read_mostly;

void show_mem(void)
{
        int i,free = 0,total = 0,reserved = 0;
        int shared = 0, cached = 0;

        printk(KERN_INFO "Mem-info:\n");
        show_free_areas();
        printk(KERN_INFO "Free swap:     %6ldkB\n",
                                nr_swap_pages<<(PAGE_SHIFT-10));
#ifndef CONFIG_DISCONTIGMEM
        i = max_mapnr;
        while (i-- > 0) {
                total++;
                if (PageReserved(mem_map+i))
                        reserved++;
                else if (PageSwapCache(mem_map+i))
                        cached++;
                else if (!page_count(&mem_map[i]))
                        free++;
                else
                        shared += page_count(&mem_map[i]) - 1;
        }
#else
        for (i = 0; i < npmem_ranges; i++) {
                int j;

                for (j = node_start_pfn(i); j < node_end_pfn(i); j++) {
                        struct page *p;
                        unsigned long flags;

                        pgdat_resize_lock(NODE_DATA(i), &flags);
                        p = nid_page_nr(i, j) - node_start_pfn(i);

                        total++;
                        if (PageReserved(p))
                                reserved++;
                        else if (PageSwapCache(p))
                                cached++;
                        else if (!page_count(p))
                                free++;
                        else
                                shared += page_count(p) - 1;
                        pgdat_resize_unlock(NODE_DATA(i), &flags);
                }
        }
#endif
        printk(KERN_INFO "%d pages of RAM\n", total);
        printk(KERN_INFO "%d reserved pages\n", reserved);
        printk(KERN_INFO "%d pages shared\n", shared);
        printk(KERN_INFO "%d pages swap cached\n", cached);


#ifdef CONFIG_DISCONTIGMEM
        {
                struct zonelist *zl;
                int i, j, k;

                for (i = 0; i < npmem_ranges; i++) {
                        for (j = 0; j < MAX_NR_ZONES; j++) {
                                zl = NODE_DATA(i)->node_zonelists + j;

                                printk("Zone list for zone %d on node %d: ", j, i);
                                for (k = 0; zl->zones[k] != NULL; k++) 
                                        printk("[%d/%s] ", zl->zones[k]->zone_pgdat->node_id, zl->zones[k]->name);
                                printk("\n");
                        }
                }
        }
#endif
}


static void __init map_pages(unsigned long start_vaddr, unsigned long start_paddr, unsigned long size, pgprot_t pgprot)
{
        pgd_t *pg_dir;
        pmd_t *pmd;
        pte_t *pg_table;
        unsigned long end_paddr;
        unsigned long start_pmd;
        unsigned long start_pte;
        unsigned long tmp1;
        unsigned long tmp2;
        unsigned long address;
        unsigned long ro_start;
        unsigned long ro_end;
        unsigned long fv_addr;
        unsigned long gw_addr;
        extern const unsigned long fault_vector_20;
        extern void * const linux_gateway_page;

        ro_start = __pa((unsigned long)&_text);
        ro_end   = __pa((unsigned long)&data_start);
        fv_addr  = __pa((unsigned long)&fault_vector_20) & PAGE_MASK;
        gw_addr  = __pa((unsigned long)&linux_gateway_page) & PAGE_MASK;

        end_paddr = start_paddr + size;

        pg_dir = pgd_offset_k(start_vaddr);

#if PTRS_PER_PMD == 1
        start_pmd = 0;
#else
        start_pmd = ((start_vaddr >> PMD_SHIFT) & (PTRS_PER_PMD - 1));
#endif
        start_pte = ((start_vaddr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1));

        address = start_paddr;
        while (address < end_paddr) {
#if PTRS_PER_PMD == 1
                pmd = (pmd_t *)__pa(pg_dir);
#else
                pmd = (pmd_t *)pgd_address(*pg_dir);

                /*
                 * pmd is physical at this point
                 */

                if (!pmd) {
                        pmd = (pmd_t *) alloc_bootmem_low_pages_node(NODE_DATA(0),PAGE_SIZE << PMD_ORDER);
                        pmd = (pmd_t *) __pa(pmd);
                }

                pgd_populate(NULL, pg_dir, __va(pmd));
#endif
                pg_dir++;

                /* now change pmd to kernel virtual addresses */

                pmd = (pmd_t *)__va(pmd) + start_pmd;
                for (tmp1 = start_pmd; tmp1 < PTRS_PER_PMD; tmp1++,pmd++) {

                        /*
                         * pg_table is physical at this point
                         */

                        pg_table = (pte_t *)pmd_address(*pmd);
                        if (!pg_table) {
                                pg_table = (pte_t *)
                                        alloc_bootmem_low_pages_node(NODE_DATA(0),PAGE_SIZE);
                                pg_table = (pte_t *) __pa(pg_table);
                        }

                        pmd_populate_kernel(NULL, pmd, __va(pg_table));

                        /* now change pg_table to kernel virtual addresses */

                        pg_table = (pte_t *) __va(pg_table) + start_pte;
                        for (tmp2 = start_pte; tmp2 < PTRS_PER_PTE; tmp2++,pg_table++) {
                                pte_t pte;

                                /*
                                 * Map the fault vector writable so we can
                                 * write the HPMC checksum.
                                 */
                                if (address >= ro_start && address < ro_end
                                                        && address != fv_addr
                                                        && address != gw_addr)
                                    pte = __mk_pte(address, PAGE_KERNEL_RO);
                                else
                                    pte = __mk_pte(address, pgprot);

                                if (address >= end_paddr)
                                        pte_val(pte) = 0;

                                set_pte(pg_table, pte);

                                address += PAGE_SIZE;
                        }
                        start_pte = 0;

                        if (address >= end_paddr)
                            break;
                }
                start_pmd = 0;
        }
}

/*
 * pagetable_init() sets up the page tables
 *
 * Note that gateway_init() places the Linux gateway page at page 0.
 * Since gateway pages cannot be dereferenced this has the desirable
 * side effect of trapping those pesky NULL-reference errors in the
 * kernel.
 */
static void __init pagetable_init(void)
{
        int range;

        /* Map each physical memory range to its kernel vaddr */

        for (range = 0; range < npmem_ranges; range++) {
                unsigned long start_paddr;
                unsigned long end_paddr;
                unsigned long size;

                start_paddr = pmem_ranges[range].start_pfn << PAGE_SHIFT;
                end_paddr = start_paddr + (pmem_ranges[range].pages << PAGE_SHIFT);
                size = pmem_ranges[range].pages << PAGE_SHIFT;

                map_pages((unsigned long)__va(start_paddr), start_paddr,
                        size, PAGE_KERNEL);
        }

#ifdef CONFIG_BLK_DEV_INITRD
        if (initrd_end && initrd_end > mem_limit) {
                printk("initrd: mapping %08lx-%08lx\n", initrd_start, initrd_end);
                map_pages(initrd_start, __pa(initrd_start),
                        initrd_end - initrd_start, PAGE_KERNEL);
        }
#endif

        empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
        memset(empty_zero_page, 0, PAGE_SIZE);
}

static void __init gateway_init(void)
{
        unsigned long linux_gateway_page_addr;
        /* FIXME: This is 'const' in order to trick the compiler
           into not treating it as DP-relative data. */
        extern void * const linux_gateway_page;

        linux_gateway_page_addr = LINUX_GATEWAY_ADDR & PAGE_MASK;

        /*
         * Setup Linux Gateway page.
         *
         * The Linux gateway page will reside in kernel space (on virtual
         * page 0), so it doesn't need to be aliased into user space.
         */

        map_pages(linux_gateway_page_addr, __pa(&linux_gateway_page),
                PAGE_SIZE, PAGE_GATEWAY);
}

#ifdef CONFIG_HPUX
void
map_hpux_gateway_page(struct task_struct *tsk, struct mm_struct *mm)
{
        pgd_t *pg_dir;
        pmd_t *pmd;
        pte_t *pg_table;
        unsigned long start_pmd;
        unsigned long start_pte;
        unsigned long address;
        unsigned long hpux_gw_page_addr;
        /* FIXME: This is 'const' in order to trick the compiler
           into not treating it as DP-relative data. */
        extern void * const hpux_gateway_page;

        hpux_gw_page_addr = HPUX_GATEWAY_ADDR & PAGE_MASK;

        /*
         * Setup HP-UX Gateway page.
         *
         * The HP-UX gateway page resides in the user address space,
         * so it needs to be aliased into each process.
         */

        pg_dir = pgd_offset(mm,hpux_gw_page_addr);

#if PTRS_PER_PMD == 1
        start_pmd = 0;
#else
        start_pmd = ((hpux_gw_page_addr >> PMD_SHIFT) & (PTRS_PER_PMD - 1));
#endif
        start_pte = ((hpux_gw_page_addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1));

        address = __pa(&hpux_gateway_page);
#if PTRS_PER_PMD == 1
        pmd = (pmd_t *)__pa(pg_dir);
#else
        pmd = (pmd_t *) pgd_address(*pg_dir);

        /*
         * pmd is physical at this point
         */

        if (!pmd) {
                pmd = (pmd_t *) get_zeroed_page(GFP_KERNEL);
                pmd = (pmd_t *) __pa(pmd);
        }

        __pgd_val_set(*pg_dir, PxD_FLAG_PRESENT | PxD_FLAG_VALID | (unsigned long) pmd);
#endif
        /* now change pmd to kernel virtual addresses */

        pmd = (pmd_t *)__va(pmd) + start_pmd;

        /*
         * pg_table is physical at this point
         */

        pg_table = (pte_t *) pmd_address(*pmd);
        if (!pg_table)
                pg_table = (pte_t *) __pa(get_zeroed_page(GFP_KERNEL));

        __pmd_val_set(*pmd, PxD_FLAG_PRESENT | PxD_FLAG_VALID | (unsigned long) pg_table);

        /* now change pg_table to kernel virtual addresses */

        pg_table = (pte_t *) __va(pg_table) + start_pte;
        set_pte(pg_table, __mk_pte(address, PAGE_GATEWAY));
}
EXPORT_SYMBOL(map_hpux_gateway_page);
#endif

void __init paging_init(void)
{
        int i;

        setup_bootmem();
        pagetable_init();
        gateway_init();
        flush_cache_all_local(); /* start with known state */
        flush_tlb_all_local(NULL);

        for (i = 0; i < npmem_ranges; i++) {
                unsigned long zones_size[MAX_NR_ZONES] = { 0, 0, 0 };

                /* We have an IOMMU, so all memory can go into a single
                   ZONE_DMA zone. */
                zones_size[ZONE_DMA] = pmem_ranges[i].pages;

#ifdef CONFIG_DISCONTIGMEM
                /* Need to initialize the pfnnid_map before we can initialize
                   the zone */
                {
                    int j;
                    for (j = (pmem_ranges[i].start_pfn >> PFNNID_SHIFT);
                         j <= ((pmem_ranges[i].start_pfn + pmem_ranges[i].pages) >> PFNNID_SHIFT);
                         j++) {
                        pfnnid_map[j] = i;
                    }
                }
#endif

                free_area_init_node(i, NODE_DATA(i), zones_size,
                                pmem_ranges[i].start_pfn, NULL);
        }
}

#ifdef CONFIG_PA20

/*
 * Currently, all PA20 chips have 18 bit protection id's, which is the
 * limiting factor (space ids are 32 bits).
 */

#define NR_SPACE_IDS 262144

#else

/*
 * Currently we have a one-to-one relationship between space id's and
 * protection id's. Older parisc chips (PCXS, PCXT, PCXL, PCXL2) only
 * support 15 bit protection id's, so that is the limiting factor.
 * PCXT' has 18 bit protection id's, but only 16 bit spaceids, so it's
 * probably not worth the effort for a special case here.
 */

#define NR_SPACE_IDS 32768

#endif  /* !CONFIG_PA20 */

#define RECYCLE_THRESHOLD (NR_SPACE_IDS / 2)
#define SID_ARRAY_SIZE  (NR_SPACE_IDS / (8 * sizeof(long)))

static unsigned long space_id[SID_ARRAY_SIZE] = { 1 }; /* disallow space 0 */
static unsigned long dirty_space_id[SID_ARRAY_SIZE];
static unsigned long space_id_index;
static unsigned long free_space_ids = NR_SPACE_IDS - 1;
static unsigned long dirty_space_ids = 0;

static DEFINE_SPINLOCK(sid_lock);

unsigned long alloc_sid(void)
{
        unsigned long index;

        spin_lock(&sid_lock);

        if (free_space_ids == 0) {
                if (dirty_space_ids != 0) {
                        spin_unlock(&sid_lock);
                        flush_tlb_all(); /* flush_tlb_all() calls recycle_sids() */
                        spin_lock(&sid_lock);
                }
                if (free_space_ids == 0)
                        BUG();
        }

        free_space_ids--;

        index = find_next_zero_bit(space_id, NR_SPACE_IDS, space_id_index);
        space_id[index >> SHIFT_PER_LONG] |= (1L << (index & (BITS_PER_LONG - 1)));
        space_id_index = index;

        spin_unlock(&sid_lock);

        return index << SPACEID_SHIFT;
}

void free_sid(unsigned long spaceid)
{
        unsigned long index = spaceid >> SPACEID_SHIFT;
        unsigned long *dirty_space_offset;

        dirty_space_offset = dirty_space_id + (index >> SHIFT_PER_LONG);
        index &= (BITS_PER_LONG - 1);

        spin_lock(&sid_lock);

        if (*dirty_space_offset & (1L << index))
            BUG(); /* attempt to free space id twice */

        *dirty_space_offset |= (1L << index);
        dirty_space_ids++;

        spin_unlock(&sid_lock);
}


#ifdef CONFIG_SMP
static void get_dirty_sids(unsigned long *ndirtyptr,unsigned long *dirty_array)
{
        int i;

        /* NOTE: sid_lock must be held upon entry */

        *ndirtyptr = dirty_space_ids;
        if (dirty_space_ids != 0) {
            for (i = 0; i < SID_ARRAY_SIZE; i++) {
                dirty_array[i] = dirty_space_id[i];
                dirty_space_id[i] = 0;
            }
            dirty_space_ids = 0;
        }

        return;
}

static void recycle_sids(unsigned long ndirty,unsigned long *dirty_array)
{
        int i;

        /* NOTE: sid_lock must be held upon entry */

        if (ndirty != 0) {
                for (i = 0; i < SID_ARRAY_SIZE; i++) {
                        space_id[i] ^= dirty_array[i];
                }

                free_space_ids += ndirty;
                space_id_index = 0;
        }
}

#else /* CONFIG_SMP */

static void recycle_sids(void)
{
        int i;

        /* NOTE: sid_lock must be held upon entry */

        if (dirty_space_ids != 0) {
                for (i = 0; i < SID_ARRAY_SIZE; i++) {
                        space_id[i] ^= dirty_space_id[i];
                        dirty_space_id[i] = 0;
                }

                free_space_ids += dirty_space_ids;
                dirty_space_ids = 0;
                space_id_index = 0;
        }
}
#endif

/*
 * flush_tlb_all() calls recycle_sids(), since whenever the entire tlb is
 * purged, we can safely reuse the space ids that were released but
 * not flushed from the tlb.
 */

#ifdef CONFIG_SMP

static unsigned long recycle_ndirty;
static unsigned long recycle_dirty_array[SID_ARRAY_SIZE];
static unsigned int recycle_inuse = 0;

void flush_tlb_all(void)
{
        int do_recycle;

        do_recycle = 0;
        spin_lock(&sid_lock);
        if (dirty_space_ids > RECYCLE_THRESHOLD) {
            if (recycle_inuse) {
                BUG();  /* FIXME: Use a semaphore/wait queue here */
            }
            get_dirty_sids(&recycle_ndirty,recycle_dirty_array);
            recycle_inuse++;
            do_recycle++;
        }
        spin_unlock(&sid_lock);
        on_each_cpu(flush_tlb_all_local, NULL, 1, 1);
        if (do_recycle) {
            spin_lock(&sid_lock);
            recycle_sids(recycle_ndirty,recycle_dirty_array);
            recycle_inuse = 0;
            spin_unlock(&sid_lock);
        }
}
#else
void flush_tlb_all(void)
{
        spin_lock(&sid_lock);
        flush_tlb_all_local(NULL);
        recycle_sids();
        spin_unlock(&sid_lock);
}
#endif

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
#if 0
        if (start < end)
                printk(KERN_INFO "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);
                num_physpages++;
                totalram_pages++;
        }
#endif
}
#endif