553 lines
13 KiB
C
553 lines
13 KiB
C
/*
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* PPC64 (POWER4) Huge TLB Page Support for Kernel.
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*
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* Copyright (C) 2003 David Gibson, IBM Corporation.
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*
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* Based on the IA-32 version:
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* Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
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*/
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/pagemap.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include <linux/sysctl.h>
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#include <asm/mman.h>
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#include <asm/pgalloc.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/mmu_context.h>
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#include <asm/machdep.h>
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#include <asm/cputable.h>
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#include <asm/tlb.h>
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#include <asm/spu.h>
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#include <linux/sysctl.h>
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#define NUM_LOW_AREAS (0x100000000UL >> SID_SHIFT)
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#define NUM_HIGH_AREAS (PGTABLE_RANGE >> HTLB_AREA_SHIFT)
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#ifdef CONFIG_PPC_64K_PAGES
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#define HUGEPTE_INDEX_SIZE (PMD_SHIFT-HPAGE_SHIFT)
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#else
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#define HUGEPTE_INDEX_SIZE (PUD_SHIFT-HPAGE_SHIFT)
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#endif
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#define PTRS_PER_HUGEPTE (1 << HUGEPTE_INDEX_SIZE)
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#define HUGEPTE_TABLE_SIZE (sizeof(pte_t) << HUGEPTE_INDEX_SIZE)
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#define HUGEPD_SHIFT (HPAGE_SHIFT + HUGEPTE_INDEX_SIZE)
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#define HUGEPD_SIZE (1UL << HUGEPD_SHIFT)
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#define HUGEPD_MASK (~(HUGEPD_SIZE-1))
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#define huge_pgtable_cache (pgtable_cache[HUGEPTE_CACHE_NUM])
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/* Flag to mark huge PD pointers. This means pmd_bad() and pud_bad()
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* will choke on pointers to hugepte tables, which is handy for
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* catching screwups early. */
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#define HUGEPD_OK 0x1
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typedef struct { unsigned long pd; } hugepd_t;
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#define hugepd_none(hpd) ((hpd).pd == 0)
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static inline pte_t *hugepd_page(hugepd_t hpd)
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{
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BUG_ON(!(hpd.pd & HUGEPD_OK));
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return (pte_t *)(hpd.pd & ~HUGEPD_OK);
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}
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static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr)
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{
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unsigned long idx = ((addr >> HPAGE_SHIFT) & (PTRS_PER_HUGEPTE-1));
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pte_t *dir = hugepd_page(*hpdp);
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return dir + idx;
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}
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static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
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unsigned long address)
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{
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pte_t *new = kmem_cache_alloc(huge_pgtable_cache,
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GFP_KERNEL|__GFP_REPEAT);
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if (! new)
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return -ENOMEM;
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spin_lock(&mm->page_table_lock);
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if (!hugepd_none(*hpdp))
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kmem_cache_free(huge_pgtable_cache, new);
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else
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hpdp->pd = (unsigned long)new | HUGEPD_OK;
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spin_unlock(&mm->page_table_lock);
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return 0;
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}
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/* Modelled after find_linux_pte() */
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pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pg;
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pud_t *pu;
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BUG_ON(get_slice_psize(mm, addr) != mmu_huge_psize);
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addr &= HPAGE_MASK;
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pg = pgd_offset(mm, addr);
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if (!pgd_none(*pg)) {
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pu = pud_offset(pg, addr);
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if (!pud_none(*pu)) {
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#ifdef CONFIG_PPC_64K_PAGES
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pmd_t *pm;
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pm = pmd_offset(pu, addr);
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if (!pmd_none(*pm))
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return hugepte_offset((hugepd_t *)pm, addr);
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#else
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return hugepte_offset((hugepd_t *)pu, addr);
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#endif
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}
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}
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return NULL;
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}
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pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pg;
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pud_t *pu;
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hugepd_t *hpdp = NULL;
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BUG_ON(get_slice_psize(mm, addr) != mmu_huge_psize);
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addr &= HPAGE_MASK;
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pg = pgd_offset(mm, addr);
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pu = pud_alloc(mm, pg, addr);
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if (pu) {
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#ifdef CONFIG_PPC_64K_PAGES
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pmd_t *pm;
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pm = pmd_alloc(mm, pu, addr);
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if (pm)
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hpdp = (hugepd_t *)pm;
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#else
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hpdp = (hugepd_t *)pu;
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#endif
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}
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if (! hpdp)
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return NULL;
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if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr))
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return NULL;
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return hugepte_offset(hpdp, addr);
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}
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int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
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{
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return 0;
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}
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static void free_hugepte_range(struct mmu_gather *tlb, hugepd_t *hpdp)
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{
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pte_t *hugepte = hugepd_page(*hpdp);
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hpdp->pd = 0;
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tlb->need_flush = 1;
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pgtable_free_tlb(tlb, pgtable_free_cache(hugepte, HUGEPTE_CACHE_NUM,
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PGF_CACHENUM_MASK));
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}
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#ifdef CONFIG_PPC_64K_PAGES
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static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
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unsigned long addr, unsigned long end,
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unsigned long floor, unsigned long ceiling)
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{
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pmd_t *pmd;
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unsigned long next;
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unsigned long start;
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start = addr;
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pmd = pmd_offset(pud, addr);
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do {
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next = pmd_addr_end(addr, end);
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if (pmd_none(*pmd))
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continue;
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free_hugepte_range(tlb, (hugepd_t *)pmd);
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} while (pmd++, addr = next, addr != end);
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start &= PUD_MASK;
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if (start < floor)
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return;
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if (ceiling) {
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ceiling &= PUD_MASK;
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if (!ceiling)
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return;
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}
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if (end - 1 > ceiling - 1)
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return;
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pmd = pmd_offset(pud, start);
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pud_clear(pud);
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pmd_free_tlb(tlb, pmd);
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}
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#endif
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static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
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unsigned long addr, unsigned long end,
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unsigned long floor, unsigned long ceiling)
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{
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pud_t *pud;
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unsigned long next;
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unsigned long start;
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start = addr;
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pud = pud_offset(pgd, addr);
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do {
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next = pud_addr_end(addr, end);
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#ifdef CONFIG_PPC_64K_PAGES
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if (pud_none_or_clear_bad(pud))
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continue;
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hugetlb_free_pmd_range(tlb, pud, addr, next, floor, ceiling);
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#else
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if (pud_none(*pud))
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continue;
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free_hugepte_range(tlb, (hugepd_t *)pud);
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#endif
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} while (pud++, addr = next, addr != end);
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start &= PGDIR_MASK;
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if (start < floor)
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return;
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if (ceiling) {
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ceiling &= PGDIR_MASK;
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if (!ceiling)
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return;
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}
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if (end - 1 > ceiling - 1)
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return;
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pud = pud_offset(pgd, start);
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pgd_clear(pgd);
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pud_free_tlb(tlb, pud);
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}
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/*
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* This function frees user-level page tables of a process.
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*
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* Must be called with pagetable lock held.
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*/
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void hugetlb_free_pgd_range(struct mmu_gather **tlb,
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unsigned long addr, unsigned long end,
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unsigned long floor, unsigned long ceiling)
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{
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pgd_t *pgd;
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unsigned long next;
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unsigned long start;
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/*
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* Comments below take from the normal free_pgd_range(). They
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* apply here too. The tests against HUGEPD_MASK below are
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* essential, because we *don't* test for this at the bottom
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* level. Without them we'll attempt to free a hugepte table
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* when we unmap just part of it, even if there are other
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* active mappings using it.
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*
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* The next few lines have given us lots of grief...
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*
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* Why are we testing HUGEPD* at this top level? Because
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* often there will be no work to do at all, and we'd prefer
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* not to go all the way down to the bottom just to discover
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* that.
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*
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* Why all these "- 1"s? Because 0 represents both the bottom
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* of the address space and the top of it (using -1 for the
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* top wouldn't help much: the masks would do the wrong thing).
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* The rule is that addr 0 and floor 0 refer to the bottom of
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* the address space, but end 0 and ceiling 0 refer to the top
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* Comparisons need to use "end - 1" and "ceiling - 1" (though
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* that end 0 case should be mythical).
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*
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* Wherever addr is brought up or ceiling brought down, we
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* must be careful to reject "the opposite 0" before it
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* confuses the subsequent tests. But what about where end is
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* brought down by HUGEPD_SIZE below? no, end can't go down to
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* 0 there.
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*
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* Whereas we round start (addr) and ceiling down, by different
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* masks at different levels, in order to test whether a table
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* now has no other vmas using it, so can be freed, we don't
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* bother to round floor or end up - the tests don't need that.
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*/
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addr &= HUGEPD_MASK;
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if (addr < floor) {
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addr += HUGEPD_SIZE;
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if (!addr)
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return;
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}
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if (ceiling) {
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ceiling &= HUGEPD_MASK;
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if (!ceiling)
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return;
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}
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if (end - 1 > ceiling - 1)
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end -= HUGEPD_SIZE;
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if (addr > end - 1)
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return;
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start = addr;
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pgd = pgd_offset((*tlb)->mm, addr);
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do {
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BUG_ON(get_slice_psize((*tlb)->mm, addr) != mmu_huge_psize);
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next = pgd_addr_end(addr, end);
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if (pgd_none_or_clear_bad(pgd))
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continue;
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hugetlb_free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
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} while (pgd++, addr = next, addr != end);
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}
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void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep, pte_t pte)
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{
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if (pte_present(*ptep)) {
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/* We open-code pte_clear because we need to pass the right
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* argument to hpte_need_flush (huge / !huge). Might not be
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* necessary anymore if we make hpte_need_flush() get the
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* page size from the slices
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*/
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pte_update(mm, addr & HPAGE_MASK, ptep, ~0UL, 1);
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}
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*ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
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}
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pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep)
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{
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unsigned long old = pte_update(mm, addr, ptep, ~0UL, 1);
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return __pte(old);
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}
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struct page *
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follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
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{
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pte_t *ptep;
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struct page *page;
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if (get_slice_psize(mm, address) != mmu_huge_psize)
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return ERR_PTR(-EINVAL);
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ptep = huge_pte_offset(mm, address);
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page = pte_page(*ptep);
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if (page)
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page += (address % HPAGE_SIZE) / PAGE_SIZE;
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return page;
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}
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int pmd_huge(pmd_t pmd)
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{
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return 0;
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}
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struct page *
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follow_huge_pmd(struct mm_struct *mm, unsigned long address,
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pmd_t *pmd, int write)
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{
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BUG();
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return NULL;
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}
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unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
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unsigned long len, unsigned long pgoff,
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unsigned long flags)
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{
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return slice_get_unmapped_area(addr, len, flags,
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mmu_huge_psize, 1, 0);
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}
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/*
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* Called by asm hashtable.S for doing lazy icache flush
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*/
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static unsigned int hash_huge_page_do_lazy_icache(unsigned long rflags,
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pte_t pte, int trap)
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{
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struct page *page;
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int i;
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if (!pfn_valid(pte_pfn(pte)))
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return rflags;
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page = pte_page(pte);
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/* page is dirty */
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if (!test_bit(PG_arch_1, &page->flags) && !PageReserved(page)) {
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if (trap == 0x400) {
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for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++)
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__flush_dcache_icache(page_address(page+i));
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set_bit(PG_arch_1, &page->flags);
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} else {
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rflags |= HPTE_R_N;
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}
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}
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return rflags;
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}
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int hash_huge_page(struct mm_struct *mm, unsigned long access,
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unsigned long ea, unsigned long vsid, int local,
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unsigned long trap)
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{
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pte_t *ptep;
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unsigned long old_pte, new_pte;
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unsigned long va, rflags, pa;
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long slot;
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int err = 1;
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ptep = huge_pte_offset(mm, ea);
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/* Search the Linux page table for a match with va */
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va = (vsid << 28) | (ea & 0x0fffffff);
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/*
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* If no pte found or not present, send the problem up to
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* do_page_fault
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*/
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if (unlikely(!ptep || pte_none(*ptep)))
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goto out;
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/*
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* Check the user's access rights to the page. If access should be
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* prevented then send the problem up to do_page_fault.
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*/
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if (unlikely(access & ~pte_val(*ptep)))
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goto out;
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/*
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* At this point, we have a pte (old_pte) which can be used to build
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* or update an HPTE. There are 2 cases:
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*
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* 1. There is a valid (present) pte with no associated HPTE (this is
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* the most common case)
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* 2. There is a valid (present) pte with an associated HPTE. The
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* current values of the pp bits in the HPTE prevent access
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* because we are doing software DIRTY bit management and the
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* page is currently not DIRTY.
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*/
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do {
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old_pte = pte_val(*ptep);
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if (old_pte & _PAGE_BUSY)
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goto out;
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new_pte = old_pte | _PAGE_BUSY |
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_PAGE_ACCESSED | _PAGE_HASHPTE;
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} while(old_pte != __cmpxchg_u64((unsigned long *)ptep,
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old_pte, new_pte));
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rflags = 0x2 | (!(new_pte & _PAGE_RW));
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/* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
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rflags |= ((new_pte & _PAGE_EXEC) ? 0 : HPTE_R_N);
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if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
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/* No CPU has hugepages but lacks no execute, so we
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* don't need to worry about that case */
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rflags = hash_huge_page_do_lazy_icache(rflags, __pte(old_pte),
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trap);
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/* Check if pte already has an hpte (case 2) */
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if (unlikely(old_pte & _PAGE_HASHPTE)) {
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/* There MIGHT be an HPTE for this pte */
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unsigned long hash, slot;
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hash = hpt_hash(va, HPAGE_SHIFT);
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if (old_pte & _PAGE_F_SECOND)
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hash = ~hash;
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slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
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slot += (old_pte & _PAGE_F_GIX) >> 12;
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if (ppc_md.hpte_updatepp(slot, rflags, va, mmu_huge_psize,
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local) == -1)
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old_pte &= ~_PAGE_HPTEFLAGS;
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}
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if (likely(!(old_pte & _PAGE_HASHPTE))) {
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unsigned long hash = hpt_hash(va, HPAGE_SHIFT);
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unsigned long hpte_group;
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pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
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repeat:
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hpte_group = ((hash & htab_hash_mask) *
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HPTES_PER_GROUP) & ~0x7UL;
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/* clear HPTE slot informations in new PTE */
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new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
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/* Add in WIMG bits */
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/* XXX We should store these in the pte */
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/* --BenH: I think they are ... */
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rflags |= _PAGE_COHERENT;
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/* Insert into the hash table, primary slot */
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slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags, 0,
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mmu_huge_psize);
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/* Primary is full, try the secondary */
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if (unlikely(slot == -1)) {
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hpte_group = ((~hash & htab_hash_mask) *
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HPTES_PER_GROUP) & ~0x7UL;
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slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags,
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HPTE_V_SECONDARY,
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mmu_huge_psize);
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if (slot == -1) {
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if (mftb() & 0x1)
|
|
hpte_group = ((hash & htab_hash_mask) *
|
|
HPTES_PER_GROUP)&~0x7UL;
|
|
|
|
ppc_md.hpte_remove(hpte_group);
|
|
goto repeat;
|
|
}
|
|
}
|
|
|
|
if (unlikely(slot == -2))
|
|
panic("hash_huge_page: pte_insert failed\n");
|
|
|
|
new_pte |= (slot << 12) & (_PAGE_F_SECOND | _PAGE_F_GIX);
|
|
}
|
|
|
|
/*
|
|
* No need to use ldarx/stdcx here
|
|
*/
|
|
*ptep = __pte(new_pte & ~_PAGE_BUSY);
|
|
|
|
err = 0;
|
|
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static void zero_ctor(void *addr, struct kmem_cache *cache, unsigned long flags)
|
|
{
|
|
memset(addr, 0, kmem_cache_size(cache));
|
|
}
|
|
|
|
static int __init hugetlbpage_init(void)
|
|
{
|
|
if (!cpu_has_feature(CPU_FTR_16M_PAGE))
|
|
return -ENODEV;
|
|
|
|
huge_pgtable_cache = kmem_cache_create("hugepte_cache",
|
|
HUGEPTE_TABLE_SIZE,
|
|
HUGEPTE_TABLE_SIZE,
|
|
0,
|
|
zero_ctor, NULL);
|
|
if (! huge_pgtable_cache)
|
|
panic("hugetlbpage_init(): could not create hugepte cache\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
module_init(hugetlbpage_init);
|