pgtable_32.c

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/*
 * This file contains the routines setting up the linux page tables.
 *  -- paulus
 *
 *  Derived from arch/ppc/mm/init.c:
 *    Copyright (C) 1995-1996 Gary Thomas ([email protected])
 *
 *  Modifications by Paul Mackerras (PowerMac) ([email protected])
 *  and Cort Dougan (PReP) ([email protected])
 *    Copyright (C) 1996 Paul Mackerras
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  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/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/memblock.h>
#include <linux/slab.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/fixmap.h>
#include <asm/io.h>
#include <asm/setup.h>

#include "mmu_decl.h"

unsigned long ioremap_base;
unsigned long ioremap_bot;
EXPORT_SYMBOL(ioremap_bot); /* aka VMALLOC_END */

#if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
#define HAVE_BATS   1
#endif

#if defined(CONFIG_FSL_BOOKE)
#define HAVE_TLBCAM 1
#endif

extern char etext[], _stext[];

#ifdef HAVE_BATS
extern phys_addr_t v_mapped_by_bats(unsigned long va);
extern unsigned long p_mapped_by_bats(phys_addr_t pa);
void setbat(int index, unsigned long virt, phys_addr_t phys,
        unsigned int size, int flags);

#else /* !HAVE_BATS */
#define v_mapped_by_bats(x) (0UL)
#define p_mapped_by_bats(x) (0UL)
#endif /* HAVE_BATS */

#ifdef HAVE_TLBCAM
extern unsigned int tlbcam_index;
extern phys_addr_t v_mapped_by_tlbcam(unsigned long va);
extern unsigned long p_mapped_by_tlbcam(phys_addr_t pa);
#else /* !HAVE_TLBCAM */
#define v_mapped_by_tlbcam(x)   (0UL)
#define p_mapped_by_tlbcam(x)   (0UL)
#endif /* HAVE_TLBCAM */

#define PGDIR_ORDER (32 + PGD_T_LOG2 - PGDIR_SHIFT)

pgd_t *pgd_alloc(struct mm_struct *mm)
{
    pgd_t *ret;

    /* pgdir take page or two with 4K pages and a page fraction otherwise */
#ifndef CONFIG_PPC_4K_PAGES
    ret = kzalloc(1 << PGDIR_ORDER, GFP_KERNEL);
#else
    ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
            PGDIR_ORDER - PAGE_SHIFT);
#endif
    return ret;
}

void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
#ifndef CONFIG_PPC_4K_PAGES
    kfree((void *)pgd);
#else
    free_pages((unsigned long)pgd, PGDIR_ORDER - PAGE_SHIFT);
#endif
}

__init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
    pte_t *pte;
    extern int mem_init_done;
    extern void *early_get_page(void);

    if (mem_init_done) {
        pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
    } else {
        pte = (pte_t *)early_get_page();
        if (pte)
            clear_page(pte);
    }
    return pte;
}

pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
    struct page *ptepage;

    gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;

    ptepage = alloc_pages(flags, 0);
    if (!ptepage)
        return NULL;
    pgtable_page_ctor(ptepage);
    return ptepage;
}

void __iomem *
ioremap(phys_addr_t addr, unsigned long size)
{
    return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED,
                __builtin_return_address(0));
}
EXPORT_SYMBOL(ioremap);

void __iomem *
ioremap_wc(phys_addr_t addr, unsigned long size)
{
    return __ioremap_caller(addr, size, _PAGE_NO_CACHE,
                __builtin_return_address(0));
}
EXPORT_SYMBOL(ioremap_wc);

void __iomem *
ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
{
    /* writeable implies dirty for kernel addresses */
    if (flags & _PAGE_RW)
        flags |= _PAGE_DIRTY | _PAGE_HWWRITE;

    /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
    flags &= ~(_PAGE_USER | _PAGE_EXEC);

#ifdef _PAGE_BAP_SR
    /* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format
     * which means that we just cleared supervisor access... oops ;-) This
     * restores it
     */
    flags |= _PAGE_BAP_SR;
#endif

    return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
}
EXPORT_SYMBOL(ioremap_prot);

void __iomem *
__ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
{
    return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
}

void __iomem *
__ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
         void *caller)
{
    unsigned long v, i;
    phys_addr_t p;
    int err;

    /* Make sure we have the base flags */
    if ((flags & _PAGE_PRESENT) == 0)
        flags |= PAGE_KERNEL;

    /* Non-cacheable page cannot be coherent */
    if (flags & _PAGE_NO_CACHE)
        flags &= ~_PAGE_COHERENT;

    /*
     * Choose an address to map it to.
     * Once the vmalloc system is running, we use it.
     * Before then, we use space going down from ioremap_base
     * (ioremap_bot records where we're up to).
     */
    p = addr & PAGE_MASK;
    size = PAGE_ALIGN(addr + size) - p;

    /*
     * If the address lies within the first 16 MB, assume it's in ISA
     * memory space
     */
    if (p < 16*1024*1024)
        p += _ISA_MEM_BASE;

#ifndef CONFIG_CRASH_DUMP
    /*
     * Don't allow anybody to remap normal RAM that we're using.
     * mem_init() sets high_memory so only do the check after that.
     */
    if (mem_init_done && (p < virt_to_phys(high_memory)) &&
        !(__allow_ioremap_reserved && memblock_is_region_reserved(p, size))) {
        printk("__ioremap(): phys addr 0x%llx is RAM lr %pf\n",
               (unsigned long long)p, __builtin_return_address(0));
        return NULL;
    }
#endif

    if (size == 0)
        return NULL;

    /*
     * Is it already mapped?  Perhaps overlapped by a previous
     * BAT mapping.  If the whole area is mapped then we're done,
     * otherwise remap it since we want to keep the virt addrs for
     * each request contiguous.
     *
     * We make the assumption here that if the bottom and top
     * of the range we want are mapped then it's mapped to the
     * same virt address (and this is contiguous).
     *  -- Cort
     */
    if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
        goto out;

    if ((v = p_mapped_by_tlbcam(p)))
        goto out;

    if (mem_init_done) {
        struct vm_struct *area;
        area = get_vm_area_caller(size, VM_IOREMAP, caller);
        if (area == 0)
            return NULL;
        area->phys_addr = p;
        v = (unsigned long) area->addr;
    } else {
        v = (ioremap_bot -= size);
    }

    /*
     * Should check if it is a candidate for a BAT mapping
     */

    err = 0;
    for (i = 0; i < size && err == 0; i += PAGE_SIZE)
        err = map_page(v+i, p+i, flags);
    if (err) {
        if (mem_init_done)
            vunmap((void *)v);
        return NULL;
    }

out:
    return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
}
EXPORT_SYMBOL(__ioremap);

void iounmap(volatile void __iomem *addr)
{
    /*
     * If mapped by BATs then there is nothing to do.
     * Calling vfree() generates a benign warning.
     */
    if (v_mapped_by_bats((unsigned long)addr)) return;

    if (addr > high_memory && (unsigned long) addr < ioremap_bot)
        vunmap((void *) (PAGE_MASK & (unsigned long)addr));
}
EXPORT_SYMBOL(iounmap);

int map_page(unsigned long va, phys_addr_t pa, int flags)
{
    pmd_t *pd;
    pte_t *pg;
    int err = -ENOMEM;

    /* Use upper 10 bits of VA to index the first level map */
    pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
    /* Use middle 10 bits of VA to index the second-level map */
    pg = pte_alloc_kernel(pd, va);
    if (pg != 0) {
        err = 0;
        /* The PTE should never be already set nor present in the
         * hash table
         */
        BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) &&
               flags);
        set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
                             __pgprot(flags)));
    }
    return err;
}

/*
 * Map in a chunk of physical memory starting at start.
 */
void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
{
    unsigned long v, s, f;
    phys_addr_t p;
    int ktext;

    s = offset;
    v = PAGE_OFFSET + s;
    p = memstart_addr + s;
    for (; s < top; s += PAGE_SIZE) {
        ktext = ((char *) v >= _stext && (char *) v < etext);
        f = ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL;
        map_page(v, p, f);
#ifdef CONFIG_PPC_STD_MMU_32
        if (ktext)
            hash_preload(&init_mm, v, 0, 0x300);
#endif
        v += PAGE_SIZE;
        p += PAGE_SIZE;
    }
}

void __init mapin_ram(void)
{
    unsigned long s, top;

#ifndef CONFIG_WII
    top = total_lowmem;
    s = mmu_mapin_ram(top);
    __mapin_ram_chunk(s, top);
#else
    if (!wii_hole_size) {
        s = mmu_mapin_ram(total_lowmem);
        __mapin_ram_chunk(s, total_lowmem);
    } else {
        top = wii_hole_start;
        s = mmu_mapin_ram(top);
        __mapin_ram_chunk(s, top);

        top = memblock_end_of_DRAM();
        s = wii_mmu_mapin_mem2(top);
        __mapin_ram_chunk(s, top);
    }
#endif
}

/* Scan the real Linux page tables and return a PTE pointer for
 * a virtual address in a context.
 * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 * the PTE pointer is unmodified if PTE is not found.
 */
int
get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
{
        pgd_t   *pgd;
    pud_t   *pud;
        pmd_t   *pmd;
        pte_t   *pte;
        int     retval = 0;

        pgd = pgd_offset(mm, addr & PAGE_MASK);
        if (pgd) {
        pud = pud_offset(pgd, addr & PAGE_MASK);
        if (pud && pud_present(*pud)) {
            pmd = pmd_offset(pud, addr & PAGE_MASK);
            if (pmd_present(*pmd)) {
                pte = pte_offset_map(pmd, addr & PAGE_MASK);
                if (pte) {
                    retval = 1;
                    *ptep = pte;
                    if (pmdp)
                        *pmdp = pmd;
                    /* XXX caller needs to do pte_unmap, yuck */
                }
            }
        }
        }
        return(retval);
}

#ifdef CONFIG_DEBUG_PAGEALLOC

static int __change_page_attr(struct page *page, pgprot_t prot)
{
    pte_t *kpte;
    pmd_t *kpmd;
    unsigned long address;

    BUG_ON(PageHighMem(page));
    address = (unsigned long)page_address(page);

    if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
        return 0;
    if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
        return -EINVAL;
    __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
    wmb();
    flush_tlb_page(NULL, address);
    pte_unmap(kpte);

    return 0;
}

/*
 * Change the page attributes of an page in the linear mapping.
 *
 * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
 */
static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
{
    int i, err = 0;
    unsigned long flags;

    local_irq_save(flags);
    for (i = 0; i < numpages; i++, page++) {
        err = __change_page_attr(page, prot);
        if (err)
            break;
    }
    local_irq_restore(flags);
    return err;
}


void kernel_map_pages(struct page *page, int numpages, int enable)
{
    if (PageHighMem(page))
        return;

    change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
}
#endif /* CONFIG_DEBUG_PAGEALLOC */

static int fixmaps;

void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
{
    unsigned long address = __fix_to_virt(idx);

    if (idx >= __end_of_fixed_addresses) {
        BUG();
        return;
    }

    map_page(address, phys, pgprot_val(flags));
    fixmaps++;
}

void __this_fixmap_does_not_exist(void)
{
    WARN_ON(1);
}