a0668cdc15
Currently we have a fair bit of rather fiddly code to manage the
various kmem_caches used to store page tables of various levels. We
generally have two caches holding some combination of PGD, PUD and PMD
tables, plus several more for the special hugepage pagetables.
This patch cleans this all up by taking a different approach. Rather
than the caches being designated as for PUDs or for hugeptes for 16M
pages, the caches are simply allocated to be a specific size. Thus
sharing of caches between different types/levels of pagetables happens
naturally. The pagetable size, where needed, is passed around encoded
in the same way as {PGD,PUD,PMD}_INDEX_SIZE; that is n where the
pagetable contains 2^n pointers.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
281 lines
8.1 KiB
C
281 lines
8.1 KiB
C
/*
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* PowerPC version
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
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* and Cort Dougan (PReP) (cort@cs.nmt.edu)
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* Copyright (C) 1996 Paul Mackerras
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*
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* Derived from "arch/i386/mm/init.c"
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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*
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* Dave Engebretsen <engebret@us.ibm.com>
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* Rework for PPC64 port.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#undef DEBUG
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/mman.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/stddef.h>
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#include <linux/vmalloc.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/bootmem.h>
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#include <linux/highmem.h>
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#include <linux/idr.h>
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#include <linux/nodemask.h>
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#include <linux/module.h>
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#include <linux/poison.h>
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#include <linux/lmb.h>
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#include <asm/pgalloc.h>
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#include <asm/page.h>
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#include <asm/prom.h>
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#include <asm/rtas.h>
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#include <asm/io.h>
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#include <asm/mmu_context.h>
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#include <asm/pgtable.h>
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#include <asm/mmu.h>
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#include <asm/uaccess.h>
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#include <asm/smp.h>
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#include <asm/machdep.h>
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#include <asm/tlb.h>
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#include <asm/eeh.h>
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#include <asm/processor.h>
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#include <asm/mmzone.h>
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#include <asm/cputable.h>
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#include <asm/sections.h>
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#include <asm/system.h>
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#include <asm/iommu.h>
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#include <asm/abs_addr.h>
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#include <asm/vdso.h>
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#include "mmu_decl.h"
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#ifdef CONFIG_PPC_STD_MMU_64
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#if PGTABLE_RANGE > USER_VSID_RANGE
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#warning Limited user VSID range means pagetable space is wasted
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#endif
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#if (TASK_SIZE_USER64 < PGTABLE_RANGE) && (TASK_SIZE_USER64 < USER_VSID_RANGE)
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#warning TASK_SIZE is smaller than it needs to be.
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#endif
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#endif /* CONFIG_PPC_STD_MMU_64 */
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phys_addr_t memstart_addr = ~0;
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phys_addr_t kernstart_addr;
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void free_initmem(void)
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{
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unsigned long addr;
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addr = (unsigned long)__init_begin;
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for (; addr < (unsigned long)__init_end; addr += PAGE_SIZE) {
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memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
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ClearPageReserved(virt_to_page(addr));
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init_page_count(virt_to_page(addr));
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free_page(addr);
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totalram_pages++;
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}
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printk ("Freeing unused kernel memory: %luk freed\n",
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((unsigned long)__init_end - (unsigned long)__init_begin) >> 10);
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}
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#ifdef CONFIG_BLK_DEV_INITRD
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void free_initrd_mem(unsigned long start, unsigned long end)
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{
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if (start < end)
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printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
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for (; start < end; start += PAGE_SIZE) {
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ClearPageReserved(virt_to_page(start));
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init_page_count(virt_to_page(start));
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free_page(start);
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totalram_pages++;
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}
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}
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#endif
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static void pgd_ctor(void *addr)
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{
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memset(addr, 0, PGD_TABLE_SIZE);
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}
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static void pmd_ctor(void *addr)
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{
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memset(addr, 0, PMD_TABLE_SIZE);
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}
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struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE];
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/*
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* Create a kmem_cache() for pagetables. This is not used for PTE
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* pages - they're linked to struct page, come from the normal free
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* pages pool and have a different entry size (see real_pte_t) to
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* everything else. Caches created by this function are used for all
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* the higher level pagetables, and for hugepage pagetables.
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*/
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void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
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{
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char *name;
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unsigned long table_size = sizeof(void *) << shift;
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unsigned long align = table_size;
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/* When batching pgtable pointers for RCU freeing, we store
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* the index size in the low bits. Table alignment must be
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* big enough to fit it */
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unsigned long minalign = MAX_PGTABLE_INDEX_SIZE + 1;
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struct kmem_cache *new;
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/* It would be nice if this was a BUILD_BUG_ON(), but at the
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* moment, gcc doesn't seem to recognize is_power_of_2 as a
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* constant expression, so so much for that. */
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BUG_ON(!is_power_of_2(minalign));
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BUG_ON((shift < 1) || (shift > MAX_PGTABLE_INDEX_SIZE));
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if (PGT_CACHE(shift))
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return; /* Already have a cache of this size */
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align = max_t(unsigned long, align, minalign);
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name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
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new = kmem_cache_create(name, table_size, align, 0, ctor);
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PGT_CACHE(shift) = new;
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pr_debug("Allocated pgtable cache for order %d\n", shift);
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}
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void pgtable_cache_init(void)
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{
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pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor);
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pgtable_cache_add(PMD_INDEX_SIZE, pmd_ctor);
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if (!PGT_CACHE(PGD_INDEX_SIZE) || !PGT_CACHE(PMD_INDEX_SIZE))
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panic("Couldn't allocate pgtable caches");
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/* In all current configs, when the PUD index exists it's the
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* same size as either the pgd or pmd index. Verify that the
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* initialization above has also created a PUD cache. This
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* will need re-examiniation if we add new possibilities for
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* the pagetable layout. */
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BUG_ON(PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE));
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}
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#ifdef CONFIG_SPARSEMEM_VMEMMAP
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/*
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* Given an address within the vmemmap, determine the pfn of the page that
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* represents the start of the section it is within. Note that we have to
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* do this by hand as the proffered address may not be correctly aligned.
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* Subtraction of non-aligned pointers produces undefined results.
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*/
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static unsigned long __meminit vmemmap_section_start(unsigned long page)
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{
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unsigned long offset = page - ((unsigned long)(vmemmap));
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/* Return the pfn of the start of the section. */
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return (offset / sizeof(struct page)) & PAGE_SECTION_MASK;
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}
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/*
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* Check if this vmemmap page is already initialised. If any section
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* which overlaps this vmemmap page is initialised then this page is
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* initialised already.
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*/
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static int __meminit vmemmap_populated(unsigned long start, int page_size)
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{
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unsigned long end = start + page_size;
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for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page)))
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if (pfn_valid(vmemmap_section_start(start)))
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return 1;
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return 0;
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}
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/* On hash-based CPUs, the vmemmap is bolted in the hash table.
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*
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* On Book3E CPUs, the vmemmap is currently mapped in the top half of
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* the vmalloc space using normal page tables, though the size of
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* pages encoded in the PTEs can be different
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*/
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#ifdef CONFIG_PPC_BOOK3E
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static void __meminit vmemmap_create_mapping(unsigned long start,
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unsigned long page_size,
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unsigned long phys)
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{
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/* Create a PTE encoding without page size */
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unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED |
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_PAGE_KERNEL_RW;
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/* PTEs only contain page size encodings up to 32M */
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BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf);
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/* Encode the size in the PTE */
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flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8;
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/* For each PTE for that area, map things. Note that we don't
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* increment phys because all PTEs are of the large size and
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* thus must have the low bits clear
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*/
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for (i = 0; i < page_size; i += PAGE_SIZE)
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BUG_ON(map_kernel_page(start + i, phys, flags));
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}
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#else /* CONFIG_PPC_BOOK3E */
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static void __meminit vmemmap_create_mapping(unsigned long start,
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unsigned long page_size,
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unsigned long phys)
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{
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int mapped = htab_bolt_mapping(start, start + page_size, phys,
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PAGE_KERNEL, mmu_vmemmap_psize,
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mmu_kernel_ssize);
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BUG_ON(mapped < 0);
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}
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#endif /* CONFIG_PPC_BOOK3E */
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int __meminit vmemmap_populate(struct page *start_page,
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unsigned long nr_pages, int node)
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{
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unsigned long start = (unsigned long)start_page;
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unsigned long end = (unsigned long)(start_page + nr_pages);
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unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
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/* Align to the page size of the linear mapping. */
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start = _ALIGN_DOWN(start, page_size);
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pr_debug("vmemmap_populate page %p, %ld pages, node %d\n",
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start_page, nr_pages, node);
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pr_debug(" -> map %lx..%lx\n", start, end);
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for (; start < end; start += page_size) {
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void *p;
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if (vmemmap_populated(start, page_size))
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continue;
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p = vmemmap_alloc_block(page_size, node);
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if (!p)
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return -ENOMEM;
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pr_debug(" * %016lx..%016lx allocated at %p\n",
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start, start + page_size, p);
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vmemmap_create_mapping(start, page_size, __pa(p));
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}
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return 0;
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}
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#endif /* CONFIG_SPARSEMEM_VMEMMAP */
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