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* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (
* Modifications by Paul Mackerras (PowerMac) (
* and Cort Dougan (PReP) (
* Copyright (C) 1996 Paul Mackerras
* Derived from "arch/i386/mm/init.c"
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
* Dave Engebretsen <>
* 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"
#warning Limited user VSID range means pagetable space is wasted
#warning TASK_SIZE is smaller than it needs to be.
#endif /* CONFIG_PPC_STD_MMU_64 */
phys_addr_t memstart_addr = ~0;
phys_addr_t 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 * 2);
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,
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((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);
pgtable_cache[shift - 1] = 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_CACHE_INDEX, pmd_ctor);
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. */
* 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
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 |
/* 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,
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)) {
return NULL;
num_left = PAGE_SIZE / sizeof(struct vmemmap_backing);
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)) {
vmem_back->phys = phys;
vmem_back->virt_addr = start;
vmem_back->list = vmemmap_list;
vmemmap_list = vmem_back;
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
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 %lx..%lx, node %d\n", start, end, node);
for (; start < end; start += page_size) {
void *p;
if (vmemmap_populated(start, page_size))
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;
void vmemmap_free(unsigned long start, unsigned long end)
void register_page_bootmem_memmap(unsigned long section_nr,
struct page *start_page, unsigned long size)
* We do not have access to the sparsemem vmemmap, so we fallback to
* walking the list of sparsemem blocks which we already maintain for
* the sake of crashdump. In the long run, we might want to maintain
* a tree if performance of that linear walk becomes a problem.
* realmode_pfn_to_page functions can fail due to:
* 1) As real sparsemem blocks do not lay in RAM continously (they
* are in virtual address space which is not available in the real mode),
* the requested page struct can be split between blocks so get_page/put_page
* may fail.
* 2) When huge pages are used, the get_page/put_page API will fail
* in real mode as the linked addresses in the page struct are virtual
* too.
struct page *realmode_pfn_to_page(unsigned long pfn)
struct vmemmap_backing *vmem_back;
struct page *page;
unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
unsigned long pg_va = (unsigned long) pfn_to_page(pfn);
for (vmem_back = vmemmap_list; vmem_back; vmem_back = vmem_back->list) {
if (pg_va < vmem_back->virt_addr)
/* Check that page struct is not split between real pages */
if ((pg_va + sizeof(struct page)) >
(vmem_back->virt_addr + page_size))
return NULL;
page = (struct page *) (vmem_back->phys + pg_va -
return page;
return NULL;
#elif defined(CONFIG_FLATMEM)
struct page *realmode_pfn_to_page(unsigned long pfn)
struct page *page = pfn_to_page(pfn);
return page;