pgtable_64.c

Go to the documentation of this file.

/*
 *  This file contains ioremap and related functions for 64-bit machines.
 *
 *  Derived from arch/ppc64/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
 *
 *  Dave Engebretsen <[email protected]>
 *      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/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/export.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/bootmem.h>
#include <linux/memblock.h>
#include <linux/slab.h>

#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/tlb.h>
#include <asm/processor.h>
#include <asm/cputable.h>
#include <asm/sections.h>
#include <asm/firmware.h>

#include "mmu_decl.h"

/* Some sanity checking */
#if TASK_SIZE_USER64 > PGTABLE_RANGE
#error TASK_SIZE_USER64 exceeds pagetable range
#endif

#ifdef CONFIG_PPC_STD_MMU_64
#if TASK_SIZE_USER64 > (1UL << (USER_ESID_BITS + SID_SHIFT))
#error TASK_SIZE_USER64 exceeds user VSID range
#endif
#endif

unsigned long ioremap_bot = IOREMAP_BASE;

#ifdef CONFIG_PPC_MMU_NOHASH
static void *early_alloc_pgtable(unsigned long size)
{
    void *pt;

    if (init_bootmem_done)
        pt = __alloc_bootmem(size, size, __pa(MAX_DMA_ADDRESS));
    else
        pt = __va(memblock_alloc_base(size, size,
                     __pa(MAX_DMA_ADDRESS)));
    memset(pt, 0, size);

    return pt;
}
#endif /* CONFIG_PPC_MMU_NOHASH */

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

    if (slab_is_available()) {
        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(pmdp, ea);
        if (!ptep)
            return -ENOMEM;
        set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
                              __pgprot(flags)));
    } else {
#ifdef CONFIG_PPC_MMU_NOHASH
        /* Warning ! This will blow up if bootmem is not initialized
         * which our ppc64 code is keen to do that, we'll need to
         * fix it and/or be more careful
         */
        pgdp = pgd_offset_k(ea);
#ifdef PUD_TABLE_SIZE
        if (pgd_none(*pgdp)) {
            pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
            BUG_ON(pudp == NULL);
            pgd_populate(&init_mm, pgdp, pudp);
        }
#endif /* PUD_TABLE_SIZE */
        pudp = pud_offset(pgdp, ea);
        if (pud_none(*pudp)) {
            pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
            BUG_ON(pmdp == NULL);
            pud_populate(&init_mm, pudp, pmdp);
        }
        pmdp = pmd_offset(pudp, ea);
        if (!pmd_present(*pmdp)) {
            ptep = early_alloc_pgtable(PAGE_SIZE);
            BUG_ON(ptep == NULL);
            pmd_populate_kernel(&init_mm, pmdp, ptep);
        }
        ptep = pte_offset_kernel(pmdp, ea);
        set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
                              __pgprot(flags)));
#else /* CONFIG_PPC_MMU_NOHASH */
        /*
         * 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.
         *
         */
        if (htab_bolt_mapping(ea, ea + PAGE_SIZE, pa, flags,
                      mmu_io_psize, mmu_kernel_ssize)) {
            printk(KERN_ERR "Failed to do bolted mapping IO "
                   "memory at %016lx !\n", pa);
            return -ENOMEM;
        }
#endif /* !CONFIG_PPC_MMU_NOHASH */
    }
    return 0;
}


void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
                unsigned long flags)
{
    unsigned long i;

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

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

    /* We don't support the 4K PFN hack with ioremap */
    if (flags & _PAGE_4K_PFN)
        return NULL;

    WARN_ON(pa & ~PAGE_MASK);
    WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
    WARN_ON(size & ~PAGE_MASK);

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

    return (void __iomem *)ea;
}

void __iounmap_at(void *ea, unsigned long size)
{
    WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
    WARN_ON(size & ~PAGE_MASK);

    unmap_kernel_range((unsigned long)ea, size);
}

void __iomem * __ioremap_caller(phys_addr_t addr, unsigned long size,
                unsigned long flags, void *caller)
{
    phys_addr_t paligned;
    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
     * 
     */
    paligned = addr & PAGE_MASK;
    size = PAGE_ALIGN(addr + size) - paligned;

    if ((size == 0) || (paligned == 0))
        return NULL;

    if (mem_init_done) {
        struct vm_struct *area;

        area = __get_vm_area_caller(size, VM_IOREMAP,
                        ioremap_bot, IOREMAP_END,
                        caller);
        if (area == NULL)
            return NULL;

        area->phys_addr = paligned;
        ret = __ioremap_at(paligned, area->addr, size, flags);
        if (!ret)
            vunmap(area->addr);
    } else {
        ret = __ioremap_at(paligned, (void *)ioremap_bot, size, flags);
        if (ret)
            ioremap_bot += size;
    }

    if (ret)
        ret += addr & ~PAGE_MASK;
    return ret;
}

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(phys_addr_t addr, unsigned long size)
{
    unsigned long flags = _PAGE_NO_CACHE | _PAGE_GUARDED;
    void *caller = __builtin_return_address(0);

    if (ppc_md.ioremap)
        return ppc_md.ioremap(addr, size, flags, caller);
    return __ioremap_caller(addr, size, flags, caller);
}

void __iomem * ioremap_wc(phys_addr_t addr, unsigned long size)
{
    unsigned long flags = _PAGE_NO_CACHE;
    void *caller = __builtin_return_address(0);

    if (ppc_md.ioremap)
        return ppc_md.ioremap(addr, size, flags, caller);
    return __ioremap_caller(addr, size, flags, caller);
}

void __iomem * ioremap_prot(phys_addr_t addr, unsigned long size,
                 unsigned long flags)
{
    void *caller = __builtin_return_address(0);

    /* writeable implies dirty for kernel addresses */
    if (flags & _PAGE_RW)
        flags |= _PAGE_DIRTY;

    /* 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

    if (ppc_md.ioremap)
        return ppc_md.ioremap(addr, size, flags, caller);
    return __ioremap_caller(addr, size, flags, caller);
}


/*  
 * Unmap an IO region and remove it from imalloc'd list.
 * Access to IO memory should be serialized by driver.
 */
void __iounmap(volatile void __iomem *token)
{
    void *addr;

    if (!mem_init_done)
        return;
    
    addr = (void *) ((unsigned long __force)
             PCI_FIX_ADDR(token) & PAGE_MASK);
    if ((unsigned long)addr < ioremap_bot) {
        printk(KERN_WARNING "Attempt to iounmap early bolted mapping"
               " at 0x%p\n", addr);
        return;
    }
    vunmap(addr);
}

void iounmap(volatile void __iomem *token)
{
    if (ppc_md.iounmap)
        ppc_md.iounmap(token);
    else
        __iounmap(token);
}

EXPORT_SYMBOL(ioremap);
EXPORT_SYMBOL(ioremap_wc);
EXPORT_SYMBOL(ioremap_prot);
EXPORT_SYMBOL(__ioremap);
EXPORT_SYMBOL(__ioremap_at);
EXPORT_SYMBOL(iounmap);
EXPORT_SYMBOL(__iounmap);
EXPORT_SYMBOL(__iounmap_at);