[PATCH] ppc64: Abolish ioremap_mm

[linux-2.6/openmoko-kernel/knife-kernel.git] / arch / ppc64 / mm / init.c

/*
 *  PowerPC version 
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Paul Mackerras
 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  Dave Engebretsen <engebret@us.ibm.com>
 *      Rework for PPC64 port.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 */

#include <linux/config.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/stddef.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/idr.h>
#include <linux/nodemask.h>
#include <linux/module.h>

#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/abs_addr.h>
#include <asm/prom.h>
#include <asm/lmb.h>
#include <asm/rtas.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/uaccess.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/tlb.h>
#include <asm/eeh.h>
#include <asm/processor.h>
#include <asm/mmzone.h>
#include <asm/cputable.h>
#include <asm/ppcdebug.h>
#include <asm/sections.h>
#include <asm/system.h>
#include <asm/iommu.h>
#include <asm/abs_addr.h>
#include <asm/vdso.h>
#include <asm/imalloc.h>

int mem_init_done;
unsigned long ioremap_bot = IMALLOC_BASE;
static unsigned long phbs_io_bot = PHBS_IO_BASE;

extern pgd_t swapper_pg_dir[];
extern struct task_struct *current_set[NR_CPUS];

unsigned long klimit = (unsigned long)_end;

unsigned long _SDR1=0;
unsigned long _ASR=0;

/* max amount of RAM to use */
unsigned long __max_memory;

/* info on what we think the IO hole is */
unsigned long   io_hole_start;
unsigned long   io_hole_size;

void show_mem(void)
{
        unsigned long total = 0, reserved = 0;
        unsigned long shared = 0, cached = 0;
        struct page *page;
        pg_data_t *pgdat;
        unsigned long i;

        printk("Mem-info:\n");
        show_free_areas();
        printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
        for_each_pgdat(pgdat) {
                for (i = 0; i < pgdat->node_spanned_pages; i++) {
                        page = pgdat->node_mem_map + i;
                        total++;
                        if (PageReserved(page))
                                reserved++;
                        else if (PageSwapCache(page))
                                cached++;
                        else if (page_count(page))
                                shared += page_count(page) - 1;
                }
        }
        printk("%ld pages of RAM\n", total);
        printk("%ld reserved pages\n", reserved);
        printk("%ld pages shared\n", shared);
        printk("%ld pages swap cached\n", cached);
}

#ifdef CONFIG_PPC_ISERIES

void __iomem *ioremap(unsigned long addr, unsigned long size)
{
        return (void __iomem *)addr;
}

extern void __iomem *__ioremap(unsigned long addr, unsigned long size,
                       unsigned long flags)
{
        return (void __iomem *)addr;
}

void iounmap(volatile void __iomem *addr)
{
        return;
}

#else

/*
 * map_io_page currently only called by __ioremap
 * map_io_page adds an entry to the ioremap page table
 * and adds an entry to the HPT, possibly bolting it
 */
static int map_io_page(unsigned long ea, unsigned long pa, int flags)
{
        pgd_t *pgdp;
        pud_t *pudp;
        pmd_t *pmdp;
        pte_t *ptep;
        unsigned long vsid;

        if (mem_init_done) {
                spin_lock(&init_mm.page_table_lock);
                pgdp = pgd_offset_k(ea);
                pudp = pud_alloc(&init_mm, pgdp, ea);
                if (!pudp)
                        return -ENOMEM;
                pmdp = pmd_alloc(&init_mm, pudp, ea);
                if (!pmdp)
                        return -ENOMEM;
                ptep = pte_alloc_kernel(&init_mm, pmdp, ea);
                if (!ptep)
                        return -ENOMEM;
                pa = abs_to_phys(pa);
                set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
                                                          __pgprot(flags)));
                spin_unlock(&init_mm.page_table_lock);
        } else {
                unsigned long va, vpn, hash, hpteg;

                /*
                 * If the mm subsystem is not fully up, we cannot create a
                 * linux page table entry for this mapping.  Simply bolt an
                 * entry in the hardware page table.
                 */
                vsid = get_kernel_vsid(ea);
                va = (vsid << 28) | (ea & 0xFFFFFFF);
                vpn = va >> PAGE_SHIFT;

                hash = hpt_hash(vpn, 0);

                hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);

                /* Panic if a pte grpup is full */
                if (ppc_md.hpte_insert(hpteg, va, pa >> PAGE_SHIFT, 0,
                                       _PAGE_NO_CACHE|_PAGE_GUARDED|PP_RWXX,
                                       1, 0) == -1) {
                        panic("map_io_page: could not insert mapping");
                }
        }
        return 0;
}


static void __iomem * __ioremap_com(unsigned long addr, unsigned long pa,
                            unsigned long ea, unsigned long size,
                            unsigned long flags)
{
        unsigned long i;

        if ((flags & _PAGE_PRESENT) == 0)
                flags |= pgprot_val(PAGE_KERNEL);

        for (i = 0; i < size; i += PAGE_SIZE)
                if (map_io_page(ea+i, pa+i, flags))
                        return NULL;

        return (void __iomem *) (ea + (addr & ~PAGE_MASK));
}


void __iomem *
ioremap(unsigned long addr, unsigned long size)
{
        return __ioremap(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED);
}

void __iomem * __ioremap(unsigned long addr, unsigned long size,
                         unsigned long flags)
{
        unsigned long pa, ea;
        void __iomem *ret;

        /*
         * Choose an address to map it to.
         * Once the imalloc system is running, we use it.
         * Before that, we map using addresses going
         * up from ioremap_bot.  imalloc will use
         * the addresses from ioremap_bot through
         * IMALLOC_END (0xE000001fffffffff)
         * 
         */
        pa = addr & PAGE_MASK;
        size = PAGE_ALIGN(addr + size) - pa;

        if (size == 0)
                return NULL;

        if (mem_init_done) {
                struct vm_struct *area;
                area = im_get_free_area(size);
                if (area == NULL)
                        return NULL;
                ea = (unsigned long)(area->addr);
                ret = __ioremap_com(addr, pa, ea, size, flags);
                if (!ret)
                        im_free(area->addr);
        } else {
                ea = ioremap_bot;
                ret = __ioremap_com(addr, pa, ea, size, flags);
                if (ret)
                        ioremap_bot += size;
        }
        return ret;
}

#define IS_PAGE_ALIGNED(_val) ((_val) == ((_val) & PAGE_MASK))

int __ioremap_explicit(unsigned long pa, unsigned long ea,
                       unsigned long size, unsigned long flags)
{
        struct vm_struct *area;
        void __iomem *ret;
        
        /* For now, require page-aligned values for pa, ea, and size */
        if (!IS_PAGE_ALIGNED(pa) || !IS_PAGE_ALIGNED(ea) ||
            !IS_PAGE_ALIGNED(size)) {
                printk(KERN_ERR "unaligned value in %s\n", __FUNCTION__);
                return 1;
        }
        
        if (!mem_init_done) {
                /* Two things to consider in this case:
                 * 1) No records will be kept (imalloc, etc) that the region
                 *    has been remapped
                 * 2) It won't be easy to iounmap() the region later (because
                 *    of 1)
                 */
                ;
        } else {
                area = im_get_area(ea, size,
                        IM_REGION_UNUSED|IM_REGION_SUBSET|IM_REGION_EXISTS);
                if (area == NULL) {
                        /* Expected when PHB-dlpar is in play */
                        return 1;
                }
                if (ea != (unsigned long) area->addr) {
                        printk(KERN_ERR "unexpected addr return from "
                               "im_get_area\n");
                        return 1;
                }
        }
        
        ret = __ioremap_com(pa, pa, ea, size, flags);
        if (ret == NULL) {
                printk(KERN_ERR "ioremap_explicit() allocation failure !\n");
                return 1;
        }
        if (ret != (void *) ea) {
                printk(KERN_ERR "__ioremap_com() returned unexpected addr\n");
                return 1;
        }

        return 0;
}

/*  
 * Unmap an IO region and remove it from imalloc'd list.
 * Access to IO memory should be serialized by driver.
 * This code is modeled after vmalloc code - unmap_vm_area()
 *
 * XXX  what about calls before mem_init_done (ie python_countermeasures())
 */
void iounmap(volatile void __iomem *token)
{
        void *addr;

        if (!mem_init_done)
                return;
        
        addr = (void *) ((unsigned long __force) token & PAGE_MASK);

        im_free(addr);
}

static int iounmap_subset_regions(unsigned long addr, unsigned long size)
{
        struct vm_struct *area;

        /* Check whether subsets of this region exist */
        area = im_get_area(addr, size, IM_REGION_SUPERSET);
        if (area == NULL)
                return 1;

        while (area) {
                iounmap((void __iomem *) area->addr);
                area = im_get_area(addr, size,
                                IM_REGION_SUPERSET);
        }

        return 0;
}

int iounmap_explicit(volatile void __iomem *start, unsigned long size)
{
        struct vm_struct *area;
        unsigned long addr;
        int rc;
        
        addr = (unsigned long __force) start & PAGE_MASK;

        /* Verify that the region either exists or is a subset of an existing
         * region.  In the latter case, split the parent region to create 
         * the exact region 
         */
        area = im_get_area(addr, size, 
                            IM_REGION_EXISTS | IM_REGION_SUBSET);
        if (area == NULL) {
                /* Determine whether subset regions exist.  If so, unmap */
                rc = iounmap_subset_regions(addr, size);
                if (rc) {
                        printk(KERN_ERR
                               "%s() cannot unmap nonexistent range 0x%lx\n",
                                __FUNCTION__, addr);
                        return 1;
                }
        } else {
                iounmap((void __iomem *) area->addr);
        }
        /*
         * FIXME! This can't be right:
        iounmap(area->addr);
         * Maybe it should be "iounmap(area);"
         */
        return 0;
}

#endif

EXPORT_SYMBOL(ioremap);
EXPORT_SYMBOL(__ioremap);
EXPORT_SYMBOL(iounmap);

void free_initmem(void)
{
        unsigned long addr;

        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);
                totalram_pages++;
        }
        printk ("Freeing unused kernel memory: %luk freed\n",
                ((unsigned long)__init_end - (unsigned long)__init_begin) >> 10);
}

#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

static DEFINE_SPINLOCK(mmu_context_lock);
static DEFINE_IDR(mmu_context_idr);

int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
        int index;
        int err;

#ifdef CONFIG_HUGETLB_PAGE
        /* We leave htlb_segs as it was, but for a fork, we need to
         * clear the huge_pgdir. */
        mm->context.huge_pgdir = NULL;
#endif

again:
        if (!idr_pre_get(&mmu_context_idr, GFP_KERNEL))
                return -ENOMEM;

        spin_lock(&mmu_context_lock);
        err = idr_get_new_above(&mmu_context_idr, NULL, 1, &index);
        spin_unlock(&mmu_context_lock);

        if (err == -EAGAIN)
                goto again;
        else if (err)
                return err;

        if (index > MAX_CONTEXT) {
                idr_remove(&mmu_context_idr, index);
                return -ENOMEM;
        }

        mm->context.id = index;

        return 0;
}

void destroy_context(struct mm_struct *mm)
{
        spin_lock(&mmu_context_lock);
        idr_remove(&mmu_context_idr, mm->context.id);
        spin_unlock(&mmu_context_lock);

        mm->context.id = NO_CONTEXT;

        hugetlb_mm_free_pgd(mm);
}

/*
 * Do very early mm setup.
 */
void __init mm_init_ppc64(void)
{
#ifndef CONFIG_PPC_ISERIES
        unsigned long i;
#endif

        ppc64_boot_msg(0x100, "MM Init");

        /* This is the story of the IO hole... please, keep seated,
         * unfortunately, we are out of oxygen masks at the moment.
         * So we need some rough way to tell where your big IO hole
         * is. On pmac, it's between 2G and 4G, on POWER3, it's around
         * that area as well, on POWER4 we don't have one, etc...
         * We need that as a "hint" when sizing the TCE table on POWER3
         * So far, the simplest way that seem work well enough for us it
         * to just assume that the first discontinuity in our physical
         * RAM layout is the IO hole. That may not be correct in the future
         * (and isn't on iSeries but then we don't care ;)
         */

#ifndef CONFIG_PPC_ISERIES
        for (i = 1; i < lmb.memory.cnt; i++) {
                unsigned long base, prevbase, prevsize;

                prevbase = lmb.memory.region[i-1].physbase;
                prevsize = lmb.memory.region[i-1].size;
                base = lmb.memory.region[i].physbase;
                if (base > (prevbase + prevsize)) {
                        io_hole_start = prevbase + prevsize;
                        io_hole_size = base  - (prevbase + prevsize);
                        break;
                }
        }
#endif /* CONFIG_PPC_ISERIES */
        if (io_hole_start)
                printk("IO Hole assumed to be %lx -> %lx\n",
                       io_hole_start, io_hole_start + io_hole_size - 1);

        ppc64_boot_msg(0x100, "MM Init Done");
}

/*
 * This is called by /dev/mem to know if a given address has to
 * be mapped non-cacheable or not
 */
int page_is_ram(unsigned long pfn)
{
        int i;
        unsigned long paddr = (pfn << PAGE_SHIFT);

        for (i=0; i < lmb.memory.cnt; i++) {
                unsigned long base;

#ifdef CONFIG_MSCHUNKS
                base = lmb.memory.region[i].physbase;
#else
                base = lmb.memory.region[i].base;
#endif
                if ((paddr >= base) &&
                        (paddr < (base + lmb.memory.region[i].size))) {
                        return 1;
                }
        }

        return 0;
}
EXPORT_SYMBOL(page_is_ram);

/*
 * Initialize the bootmem system and give it all the memory we
 * have available.
 */
#ifndef CONFIG_DISCONTIGMEM
void __init do_init_bootmem(void)
{
        unsigned long i;
        unsigned long start, bootmap_pages;
        unsigned long total_pages = lmb_end_of_DRAM() >> PAGE_SHIFT;
        int boot_mapsize;

        /*
         * Find an area to use for the bootmem bitmap.  Calculate the size of
         * bitmap required as (Total Memory) / PAGE_SIZE / BITS_PER_BYTE.
         * Add 1 additional page in case the address isn't page-aligned.
         */
        bootmap_pages = bootmem_bootmap_pages(total_pages);

        start = abs_to_phys(lmb_alloc(bootmap_pages<<PAGE_SHIFT, PAGE_SIZE));
        BUG_ON(!start);

        boot_mapsize = init_bootmem(start >> PAGE_SHIFT, total_pages);

        max_pfn = max_low_pfn;

        /* add all physical memory to the bootmem map. Also find the first */
        for (i=0; i < lmb.memory.cnt; i++) {
                unsigned long physbase, size;

                physbase = lmb.memory.region[i].physbase;
                size = lmb.memory.region[i].size;
                free_bootmem(physbase, size);
        }

        /* reserve the sections we're already using */
        for (i=0; i < lmb.reserved.cnt; i++) {
                unsigned long physbase = lmb.reserved.region[i].physbase;
                unsigned long size = lmb.reserved.region[i].size;

                reserve_bootmem(physbase, size);
        }
}

/*
 * paging_init() sets up the page tables - in fact we've already done this.
 */
void __init paging_init(void)
{
        unsigned long zones_size[MAX_NR_ZONES];
        unsigned long zholes_size[MAX_NR_ZONES];
        unsigned long total_ram = lmb_phys_mem_size();
        unsigned long top_of_ram = lmb_end_of_DRAM();

        printk(KERN_INFO "Top of RAM: 0x%lx, Total RAM: 0x%lx\n",
               top_of_ram, total_ram);
        printk(KERN_INFO "Memory hole size: %ldMB\n",
               (top_of_ram - total_ram) >> 20);
        /*
         * All pages are DMA-able so we put them all in the DMA zone.
         */
        memset(zones_size, 0, sizeof(zones_size));
        memset(zholes_size, 0, sizeof(zholes_size));

        zones_size[ZONE_DMA] = top_of_ram >> PAGE_SHIFT;
        zholes_size[ZONE_DMA] = (top_of_ram - total_ram) >> PAGE_SHIFT;

        free_area_init_node(0, NODE_DATA(0), zones_size,
                            __pa(PAGE_OFFSET) >> PAGE_SHIFT, zholes_size);
}
#endif /* CONFIG_DISCONTIGMEM */

static struct kcore_list kcore_vmem;

static int __init setup_kcore(void)
{
        int i;

        for (i=0; i < lmb.memory.cnt; i++) {
                unsigned long physbase, size;
                struct kcore_list *kcore_mem;

                physbase = lmb.memory.region[i].physbase;
                size = lmb.memory.region[i].size;

                /* GFP_ATOMIC to avoid might_sleep warnings during boot */
                kcore_mem = kmalloc(sizeof(struct kcore_list), GFP_ATOMIC);
                if (!kcore_mem)
                        panic("mem_init: kmalloc failed\n");

                kclist_add(kcore_mem, __va(physbase), size);
        }

        kclist_add(&kcore_vmem, (void *)VMALLOC_START, VMALLOC_END-VMALLOC_START);

        return 0;
}
module_init(setup_kcore);

void __init mem_init(void)
{
#ifdef CONFIG_DISCONTIGMEM
        int nid;
#endif
        pg_data_t *pgdat;
        unsigned long i;
        struct page *page;
        unsigned long reservedpages = 0, codesize, initsize, datasize, bsssize;

        num_physpages = max_low_pfn;    /* RAM is assumed contiguous */
        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);

#ifdef CONFIG_DISCONTIGMEM
        for_each_online_node(nid) {
                if (NODE_DATA(nid)->node_spanned_pages != 0) {
                        printk("freeing bootmem node %x\n", nid);
                        totalram_pages +=
                                free_all_bootmem_node(NODE_DATA(nid));
                }
        }
#else
        max_mapnr = num_physpages;
        totalram_pages += free_all_bootmem();
#endif

        for_each_pgdat(pgdat) {
                for (i = 0; i < pgdat->node_spanned_pages; i++) {
                        page = pgdat->node_mem_map + i;
                        if (PageReserved(page))
                                reservedpages++;
                }
        }

        codesize = (unsigned long)&_etext - (unsigned long)&_stext;
        initsize = (unsigned long)&__init_end - (unsigned long)&__init_begin;
        datasize = (unsigned long)&_edata - (unsigned long)&__init_end;
        bsssize = (unsigned long)&__bss_stop - (unsigned long)&__bss_start;

        printk(KERN_INFO "Memory: %luk/%luk available (%luk kernel code, "
               "%luk reserved, %luk data, %luk bss, %luk init)\n",
                (unsigned long)nr_free_pages() << (PAGE_SHIFT-10),
                num_physpages << (PAGE_SHIFT-10),
                codesize >> 10,
                reservedpages << (PAGE_SHIFT-10),
                datasize >> 10,
                bsssize >> 10,
                initsize >> 10);

        mem_init_done = 1;

#ifdef CONFIG_PPC_ISERIES
        iommu_vio_init();
#endif
        /* Initialize the vDSO */
        vdso_init();
}

/*
 * This is called when a page has been modified by the kernel.
 * It just marks the page as not i-cache clean.  We do the i-cache
 * flush later when the page is given to a user process, if necessary.
 */
void flush_dcache_page(struct page *page)
{
        if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
                return;
        /* avoid an atomic op if possible */
        if (test_bit(PG_arch_1, &page->flags))
                clear_bit(PG_arch_1, &page->flags);
}
EXPORT_SYMBOL(flush_dcache_page);

void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
{
        clear_page(page);

        if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
                return;
        /*
         * We shouldnt have to do this, but some versions of glibc
         * require it (ld.so assumes zero filled pages are icache clean)
         * - Anton
         */

        /* avoid an atomic op if possible */
        if (test_bit(PG_arch_1, &pg->flags))
                clear_bit(PG_arch_1, &pg->flags);
}
EXPORT_SYMBOL(clear_user_page);

void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
                    struct page *pg)
{
        copy_page(vto, vfrom);

        /*
         * We should be able to use the following optimisation, however
         * there are two problems.
         * Firstly a bug in some versions of binutils meant PLT sections
         * were not marked executable.
         * Secondly the first word in the GOT section is blrl, used
         * to establish the GOT address. Until recently the GOT was
         * not marked executable.
         * - Anton
         */
#if 0
        if (!vma->vm_file && ((vma->vm_flags & VM_EXEC) == 0))
                return;
#endif

        if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
                return;

        /* avoid an atomic op if possible */
        if (test_bit(PG_arch_1, &pg->flags))
                clear_bit(PG_arch_1, &pg->flags);
}

void flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
                             unsigned long addr, int len)
{
        unsigned long maddr;

        maddr = (unsigned long)page_address(page) + (addr & ~PAGE_MASK);
        flush_icache_range(maddr, maddr + len);
}
EXPORT_SYMBOL(flush_icache_user_range);

/*
 * This is called at the end of handling a user page fault, when the
 * fault has been handled by updating a PTE in the linux page tables.
 * We use it to preload an HPTE into the hash table corresponding to
 * the updated linux PTE.
 * 
 * This must always be called with the mm->page_table_lock held
 */
void update_mmu_cache(struct vm_area_struct *vma, unsigned long ea,
                      pte_t pte)
{
        unsigned long vsid;
        void *pgdir;
        pte_t *ptep;
        int local = 0;
        cpumask_t tmp;
        unsigned long flags;

        /* handle i-cache coherency */
        if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE) &&
            !cpu_has_feature(CPU_FTR_NOEXECUTE)) {
                unsigned long pfn = pte_pfn(pte);
                if (pfn_valid(pfn)) {
                        struct page *page = pfn_to_page(pfn);
                        if (!PageReserved(page)
                            && !test_bit(PG_arch_1, &page->flags)) {
                                __flush_dcache_icache(page_address(page));
                                set_bit(PG_arch_1, &page->flags);
                        }
                }
        }

        /* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
        if (!pte_young(pte))
                return;

        pgdir = vma->vm_mm->pgd;
        if (pgdir == NULL)
                return;

        ptep = find_linux_pte(pgdir, ea);
        if (!ptep)
                return;

        vsid = get_vsid(vma->vm_mm->context.id, ea);

        local_irq_save(flags);
        tmp = cpumask_of_cpu(smp_processor_id());
        if (cpus_equal(vma->vm_mm->cpu_vm_mask, tmp))
                local = 1;

        __hash_page(ea, pte_val(pte) & (_PAGE_USER|_PAGE_RW), vsid, ptep,
                    0x300, local);
        local_irq_restore(flags);
}

void __iomem * reserve_phb_iospace(unsigned long size)
{
        void __iomem *virt_addr;
                
        if (phbs_io_bot >= IMALLOC_BASE) 
                panic("reserve_phb_iospace(): phb io space overflow\n");
                        
        virt_addr = (void __iomem *) phbs_io_bot;
        phbs_io_bot += size;

        return virt_addr;
}

kmem_cache_t *zero_cache;

static void zero_ctor(void *pte, kmem_cache_t *cache, unsigned long flags)
{
        memset(pte, 0, PAGE_SIZE);
}

void pgtable_cache_init(void)
{
        zero_cache = kmem_cache_create("zero",
                                PAGE_SIZE,
                                0,
                                SLAB_HWCACHE_ALIGN | SLAB_MUST_HWCACHE_ALIGN,
                                zero_ctor,
                                NULL);
        if (!zero_cache)
                panic("pgtable_cache_init(): could not create zero_cache!\n");
}

pgprot_t phys_mem_access_prot(struct file *file, unsigned long addr,
                              unsigned long size, pgprot_t vma_prot)
{
        if (ppc_md.phys_mem_access_prot)
                return ppc_md.phys_mem_access_prot(file, addr, size, vma_prot);

        if (!page_is_ram(addr >> PAGE_SHIFT))
                vma_prot = __pgprot(pgprot_val(vma_prot)
                                    | _PAGE_GUARDED | _PAGE_NO_CACHE);
        return vma_prot;
}
EXPORT_SYMBOL(phys_mem_access_prot);