init_64.c

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/*
 *  PowerPC version
 *    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.
 *
 */

#undef DEBUG

#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 <linux/poison.h>
#include <linux/memblock.h>
#include <linux/hugetlb.h>
#include <linux/slab.h>

#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/prom.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/sections.h>
#include <asm/iommu.h>
#include <asm/vdso.h>

#include "mmu_decl.h"

#ifdef CONFIG_PPC_STD_MMU_64
#if PGTABLE_RANGE > USER_VSID_RANGE
#warning Limited user VSID range means pagetable space is wasted
#endif

#if (TASK_SIZE_USER64 < PGTABLE_RANGE) && (TASK_SIZE_USER64 < USER_VSID_RANGE)
#warning TASK_SIZE is smaller than it needs to be.
#endif
#endif /* CONFIG_PPC_STD_MMU_64 */

phys_addr_t memstart_addr = ~0;
EXPORT_SYMBOL_GPL(memstart_addr);
phys_addr_t kernstart_addr;
EXPORT_SYMBOL_GPL(kernstart_addr);

static void pgd_ctor(void *addr)
{
    memset(addr, 0, PGD_TABLE_SIZE);
}

static void pmd_ctor(void *addr)
{
    memset(addr, 0, PMD_TABLE_SIZE);
}

struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE];

/*
 * Create a kmem_cache() for pagetables.  This is not used for PTE
 * pages - they're linked to struct page, come from the normal free
 * pages pool and have a different entry size (see real_pte_t) to
 * everything else.  Caches created by this function are used for all
 * the higher level pagetables, and for hugepage pagetables.
 */
void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
{
    char *name;
    unsigned long table_size = sizeof(void *) << shift;
    unsigned long align = table_size;

    /* When batching pgtable pointers for RCU freeing, we store
     * the index size in the low bits.  Table alignment must be
     * big enough to fit it.
     *
     * Likewise, hugeapge pagetable pointers contain a (different)
     * shift value in the low bits.  All tables must be aligned so
     * as to leave enough 0 bits in the address to contain it. */
    unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
                     HUGEPD_SHIFT_MASK + 1);
    struct kmem_cache *new;

    /* It would be nice if this was a BUILD_BUG_ON(), but at the
     * moment, gcc doesn't seem to recognize is_power_of_2 as a
     * constant expression, so so much for that. */
    BUG_ON(!is_power_of_2(minalign));
    BUG_ON((shift < 1) || (shift > MAX_PGTABLE_INDEX_SIZE));

    if (PGT_CACHE(shift))
        return; /* Already have a cache of this size */

    align = max_t(unsigned long, align, minalign);
    name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
    new = kmem_cache_create(name, table_size, align, 0, ctor);
    PGT_CACHE(shift) = new;

    pr_debug("Allocated pgtable cache for order %d\n", shift);
}


void pgtable_cache_init(void)
{
    pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor);
    pgtable_cache_add(PMD_INDEX_SIZE, pmd_ctor);
    if (!PGT_CACHE(PGD_INDEX_SIZE) || !PGT_CACHE(PMD_INDEX_SIZE))
        panic("Couldn't allocate pgtable caches");

    /* In all current configs, when the PUD index exists it's the
     * same size as either the pgd or pmd index.  Verify that the
     * initialization above has also created a PUD cache.  This
     * will need re-examiniation if we add new possibilities for
     * the pagetable layout. */
    BUG_ON(PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE));
}

#ifdef CONFIG_SPARSEMEM_VMEMMAP
/*
 * Given an address within the vmemmap, determine the pfn of the page that
 * represents the start of the section it is within.  Note that we have to
 * do this by hand as the proffered address may not be correctly aligned.
 * Subtraction of non-aligned pointers produces undefined results.
 */
static unsigned long __meminit vmemmap_section_start(unsigned long page)
{
    unsigned long offset = page - ((unsigned long)(vmemmap));

    /* Return the pfn of the start of the section. */
    return (offset / sizeof(struct page)) & PAGE_SECTION_MASK;
}

/*
 * Check if this vmemmap page is already initialised.  If any section
 * which overlaps this vmemmap page is initialised then this page is
 * initialised already.
 */
static int __meminit vmemmap_populated(unsigned long start, int page_size)
{
    unsigned long end = start + page_size;

    for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page)))
        if (pfn_valid(vmemmap_section_start(start)))
            return 1;

    return 0;
}

/* On hash-based CPUs, the vmemmap is bolted in the hash table.
 *
 * On Book3E CPUs, the vmemmap is currently mapped in the top half of
 * the vmalloc space using normal page tables, though the size of
 * pages encoded in the PTEs can be different
 */

#ifdef CONFIG_PPC_BOOK3E
static void __meminit vmemmap_create_mapping(unsigned long start,
                         unsigned long page_size,
                         unsigned long phys)
{
    /* Create a PTE encoding without page size */
    unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED |
        _PAGE_KERNEL_RW;

    /* PTEs only contain page size encodings up to 32M */
    BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf);

    /* Encode the size in the PTE */
    flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8;

    /* For each PTE for that area, map things. Note that we don't
     * increment phys because all PTEs are of the large size and
     * thus must have the low bits clear
     */
    for (i = 0; i < page_size; i += PAGE_SIZE)
        BUG_ON(map_kernel_page(start + i, phys, flags));
}
#else /* CONFIG_PPC_BOOK3E */
static void __meminit vmemmap_create_mapping(unsigned long start,
                         unsigned long page_size,
                         unsigned long phys)
{
    int  mapped = htab_bolt_mapping(start, start + page_size, phys,
                    PAGE_KERNEL, mmu_vmemmap_psize,
                    mmu_kernel_ssize);
    BUG_ON(mapped < 0);
}
#endif /* CONFIG_PPC_BOOK3E */

struct vmemmap_backing *vmemmap_list;

static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node)
{
    static struct vmemmap_backing *next;
    static int num_left;

    /* allocate a page when required and hand out chunks */
    if (!next || !num_left) {
        next = vmemmap_alloc_block(PAGE_SIZE, node);
        if (unlikely(!next)) {
            WARN_ON(1);
            return NULL;
        }
        num_left = PAGE_SIZE / sizeof(struct vmemmap_backing);
    }

    num_left--;

    return next++;
}

static __meminit void vmemmap_list_populate(unsigned long phys,
                        unsigned long start,
                        int node)
{
    struct vmemmap_backing *vmem_back;

    vmem_back = vmemmap_list_alloc(node);
    if (unlikely(!vmem_back)) {
        WARN_ON(1);
        return;
    }

    vmem_back->phys = phys;
    vmem_back->virt_addr = start;
    vmem_back->list = vmemmap_list;

    vmemmap_list = vmem_back;
}

int __meminit vmemmap_populate(struct page *start_page,
                   unsigned long nr_pages, int node)
{
    unsigned long start = (unsigned long)start_page;
    unsigned long end = (unsigned long)(start_page + nr_pages);
    unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;

    /* Align to the page size of the linear mapping. */
    start = _ALIGN_DOWN(start, page_size);

    pr_debug("vmemmap_populate page %p, %ld pages, node %d\n",
         start_page, nr_pages, node);
    pr_debug(" -> map %lx..%lx\n", start, end);

    for (; start < end; start += page_size) {
        void *p;

        if (vmemmap_populated(start, page_size))
            continue;

        p = vmemmap_alloc_block(page_size, node);
        if (!p)
            return -ENOMEM;

        vmemmap_list_populate(__pa(p), start, node);

        pr_debug("      * %016lx..%016lx allocated at %p\n",
             start, start + page_size, p);

        vmemmap_create_mapping(start, page_size, __pa(p));
    }

    return 0;
}
#endif /* CONFIG_SPARSEMEM_VMEMMAP */