1a44e14908
We had a problem on ppc64 where with more than 4 threads a large system wouldn't scale well while faulting in the .text (most of the time was spent in the kernel despite it was an userland compute intensive app). The reason is the useless overwrite of the same pte from all cpu. I fixed it this way (verified on an older kernel but the forward port is almost identical). This will benefit all archs not just ppc64. Signed-off-by: Andrea Arcangeli <andrea@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2210 lines
58 KiB
C
2210 lines
58 KiB
C
/*
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* linux/mm/memory.c
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*
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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*/
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/*
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* demand-loading started 01.12.91 - seems it is high on the list of
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* things wanted, and it should be easy to implement. - Linus
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*/
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/*
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* Ok, demand-loading was easy, shared pages a little bit tricker. Shared
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* pages started 02.12.91, seems to work. - Linus.
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*
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* Tested sharing by executing about 30 /bin/sh: under the old kernel it
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* would have taken more than the 6M I have free, but it worked well as
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* far as I could see.
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*
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* Also corrected some "invalidate()"s - I wasn't doing enough of them.
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*/
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/*
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* Real VM (paging to/from disk) started 18.12.91. Much more work and
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* thought has to go into this. Oh, well..
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* 19.12.91 - works, somewhat. Sometimes I get faults, don't know why.
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* Found it. Everything seems to work now.
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* 20.12.91 - Ok, making the swap-device changeable like the root.
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*/
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/*
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* 05.04.94 - Multi-page memory management added for v1.1.
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* Idea by Alex Bligh (alex@cconcepts.co.uk)
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*
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* 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
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* (Gerhard.Wichert@pdb.siemens.de)
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*
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* Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
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*/
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#include <linux/kernel_stat.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/mman.h>
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#include <linux/swap.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/rmap.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <asm/pgalloc.h>
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#include <asm/uaccess.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/pgtable.h>
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#include <linux/swapops.h>
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#include <linux/elf.h>
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#ifndef CONFIG_NEED_MULTIPLE_NODES
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/* use the per-pgdat data instead for discontigmem - mbligh */
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unsigned long max_mapnr;
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struct page *mem_map;
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EXPORT_SYMBOL(max_mapnr);
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EXPORT_SYMBOL(mem_map);
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#endif
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unsigned long num_physpages;
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/*
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* A number of key systems in x86 including ioremap() rely on the assumption
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* that high_memory defines the upper bound on direct map memory, then end
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* of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
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* highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
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* and ZONE_HIGHMEM.
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*/
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void * high_memory;
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unsigned long vmalloc_earlyreserve;
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EXPORT_SYMBOL(num_physpages);
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EXPORT_SYMBOL(high_memory);
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EXPORT_SYMBOL(vmalloc_earlyreserve);
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/*
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* If a p?d_bad entry is found while walking page tables, report
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* the error, before resetting entry to p?d_none. Usually (but
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* very seldom) called out from the p?d_none_or_clear_bad macros.
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*/
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void pgd_clear_bad(pgd_t *pgd)
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{
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pgd_ERROR(*pgd);
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pgd_clear(pgd);
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}
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void pud_clear_bad(pud_t *pud)
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{
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pud_ERROR(*pud);
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pud_clear(pud);
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}
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void pmd_clear_bad(pmd_t *pmd)
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{
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pmd_ERROR(*pmd);
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pmd_clear(pmd);
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}
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/*
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* Note: this doesn't free the actual pages themselves. That
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* has been handled earlier when unmapping all the memory regions.
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*/
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static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
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{
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struct page *page = pmd_page(*pmd);
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pmd_clear(pmd);
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pte_lock_deinit(page);
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pte_free_tlb(tlb, page);
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dec_page_state(nr_page_table_pages);
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tlb->mm->nr_ptes--;
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}
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static inline void 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_or_clear_bad(pmd))
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continue;
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free_pte_range(tlb, 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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static inline void 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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if (pud_none_or_clear_bad(pud))
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continue;
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free_pmd_range(tlb, pud, addr, next, floor, ceiling);
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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 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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* The next few lines have given us lots of grief...
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*
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* Why are we testing PMD* at this top level? Because often
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* there will be no work to do at all, and we'd prefer not to
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* go all the way down to the bottom just to discover 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 must
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* be careful to reject "the opposite 0" before it confuses the
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* subsequent tests. But what about where end is brought down
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* by PMD_SIZE below? no, end can't go down to 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 &= PMD_MASK;
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if (addr < floor) {
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addr += PMD_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 &= PMD_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 -= PMD_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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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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free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
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} while (pgd++, addr = next, addr != end);
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if (!(*tlb)->fullmm)
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flush_tlb_pgtables((*tlb)->mm, start, end);
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}
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void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
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unsigned long floor, unsigned long ceiling)
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{
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while (vma) {
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struct vm_area_struct *next = vma->vm_next;
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unsigned long addr = vma->vm_start;
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/*
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* Hide vma from rmap and vmtruncate before freeing pgtables
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*/
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anon_vma_unlink(vma);
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unlink_file_vma(vma);
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if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) {
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hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
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floor, next? next->vm_start: ceiling);
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} else {
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/*
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* Optimization: gather nearby vmas into one call down
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*/
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while (next && next->vm_start <= vma->vm_end + PMD_SIZE
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&& !is_hugepage_only_range(vma->vm_mm, next->vm_start,
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HPAGE_SIZE)) {
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vma = next;
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next = vma->vm_next;
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anon_vma_unlink(vma);
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unlink_file_vma(vma);
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}
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free_pgd_range(tlb, addr, vma->vm_end,
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floor, next? next->vm_start: ceiling);
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}
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vma = next;
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}
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}
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int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
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{
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struct page *new = pte_alloc_one(mm, address);
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if (!new)
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return -ENOMEM;
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pte_lock_init(new);
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spin_lock(&mm->page_table_lock);
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if (pmd_present(*pmd)) { /* Another has populated it */
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pte_lock_deinit(new);
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pte_free(new);
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} else {
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mm->nr_ptes++;
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inc_page_state(nr_page_table_pages);
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pmd_populate(mm, pmd, new);
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}
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spin_unlock(&mm->page_table_lock);
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return 0;
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}
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int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
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{
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pte_t *new = pte_alloc_one_kernel(&init_mm, address);
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if (!new)
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return -ENOMEM;
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spin_lock(&init_mm.page_table_lock);
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if (pmd_present(*pmd)) /* Another has populated it */
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pte_free_kernel(new);
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else
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pmd_populate_kernel(&init_mm, pmd, new);
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spin_unlock(&init_mm.page_table_lock);
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return 0;
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}
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static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
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{
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if (file_rss)
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add_mm_counter(mm, file_rss, file_rss);
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if (anon_rss)
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add_mm_counter(mm, anon_rss, anon_rss);
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}
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/*
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* This function is called to print an error when a pte in a
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* !VM_RESERVED region is found pointing to an invalid pfn (which
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* is an error.
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*
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* The calling function must still handle the error.
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*/
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void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
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{
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printk(KERN_ERR "Bad pte = %08llx, process = %s, "
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"vm_flags = %lx, vaddr = %lx\n",
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(long long)pte_val(pte),
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(vma->vm_mm == current->mm ? current->comm : "???"),
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vma->vm_flags, vaddr);
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dump_stack();
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}
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/*
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* copy one vm_area from one task to the other. Assumes the page tables
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* already present in the new task to be cleared in the whole range
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* covered by this vma.
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*/
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static inline void
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copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
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pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
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unsigned long addr, int *rss)
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{
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unsigned long vm_flags = vma->vm_flags;
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pte_t pte = *src_pte;
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struct page *page;
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unsigned long pfn;
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/* pte contains position in swap or file, so copy. */
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if (unlikely(!pte_present(pte))) {
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if (!pte_file(pte)) {
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swap_duplicate(pte_to_swp_entry(pte));
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/* make sure dst_mm is on swapoff's mmlist. */
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if (unlikely(list_empty(&dst_mm->mmlist))) {
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spin_lock(&mmlist_lock);
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if (list_empty(&dst_mm->mmlist))
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list_add(&dst_mm->mmlist,
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&src_mm->mmlist);
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spin_unlock(&mmlist_lock);
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}
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}
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goto out_set_pte;
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}
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|
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/* If the region is VM_RESERVED, the mapping is not
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* mapped via rmap - duplicate the pte as is.
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*/
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if (vm_flags & VM_RESERVED)
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goto out_set_pte;
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pfn = pte_pfn(pte);
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/* If the pte points outside of valid memory but
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* the region is not VM_RESERVED, we have a problem.
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*/
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if (unlikely(!pfn_valid(pfn))) {
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print_bad_pte(vma, pte, addr);
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goto out_set_pte; /* try to do something sane */
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}
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|
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page = pfn_to_page(pfn);
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|
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/*
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* If it's a COW mapping, write protect it both
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* in the parent and the child
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*/
|
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if ((vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE) {
|
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ptep_set_wrprotect(src_mm, addr, src_pte);
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pte = *src_pte;
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}
|
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|
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/*
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* If it's a shared mapping, mark it clean in
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* the child
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*/
|
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if (vm_flags & VM_SHARED)
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pte = pte_mkclean(pte);
|
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pte = pte_mkold(pte);
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get_page(page);
|
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page_dup_rmap(page);
|
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rss[!!PageAnon(page)]++;
|
|
|
|
out_set_pte:
|
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set_pte_at(dst_mm, addr, dst_pte, pte);
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}
|
|
|
|
static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
|
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pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
|
|
unsigned long addr, unsigned long end)
|
|
{
|
|
pte_t *src_pte, *dst_pte;
|
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spinlock_t *src_ptl, *dst_ptl;
|
|
int progress = 0;
|
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int rss[2];
|
|
|
|
again:
|
|
rss[1] = rss[0] = 0;
|
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dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
|
|
if (!dst_pte)
|
|
return -ENOMEM;
|
|
src_pte = pte_offset_map_nested(src_pmd, addr);
|
|
src_ptl = pte_lockptr(src_mm, src_pmd);
|
|
spin_lock(src_ptl);
|
|
|
|
do {
|
|
/*
|
|
* We are holding two locks at this point - either of them
|
|
* could generate latencies in another task on another CPU.
|
|
*/
|
|
if (progress >= 32) {
|
|
progress = 0;
|
|
if (need_resched() ||
|
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need_lockbreak(src_ptl) ||
|
|
need_lockbreak(dst_ptl))
|
|
break;
|
|
}
|
|
if (pte_none(*src_pte)) {
|
|
progress++;
|
|
continue;
|
|
}
|
|
copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
|
|
progress += 8;
|
|
} while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
|
|
|
|
spin_unlock(src_ptl);
|
|
pte_unmap_nested(src_pte - 1);
|
|
add_mm_rss(dst_mm, rss[0], rss[1]);
|
|
pte_unmap_unlock(dst_pte - 1, dst_ptl);
|
|
cond_resched();
|
|
if (addr != end)
|
|
goto again;
|
|
return 0;
|
|
}
|
|
|
|
static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
|
|
pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
|
|
unsigned long addr, unsigned long end)
|
|
{
|
|
pmd_t *src_pmd, *dst_pmd;
|
|
unsigned long next;
|
|
|
|
dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
|
|
if (!dst_pmd)
|
|
return -ENOMEM;
|
|
src_pmd = pmd_offset(src_pud, addr);
|
|
do {
|
|
next = pmd_addr_end(addr, end);
|
|
if (pmd_none_or_clear_bad(src_pmd))
|
|
continue;
|
|
if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
|
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vma, addr, next))
|
|
return -ENOMEM;
|
|
} while (dst_pmd++, src_pmd++, addr = next, addr != end);
|
|
return 0;
|
|
}
|
|
|
|
static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
|
|
pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
|
|
unsigned long addr, unsigned long end)
|
|
{
|
|
pud_t *src_pud, *dst_pud;
|
|
unsigned long next;
|
|
|
|
dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
|
|
if (!dst_pud)
|
|
return -ENOMEM;
|
|
src_pud = pud_offset(src_pgd, addr);
|
|
do {
|
|
next = pud_addr_end(addr, end);
|
|
if (pud_none_or_clear_bad(src_pud))
|
|
continue;
|
|
if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
|
|
vma, addr, next))
|
|
return -ENOMEM;
|
|
} while (dst_pud++, src_pud++, addr = next, addr != end);
|
|
return 0;
|
|
}
|
|
|
|
int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
|
|
struct vm_area_struct *vma)
|
|
{
|
|
pgd_t *src_pgd, *dst_pgd;
|
|
unsigned long next;
|
|
unsigned long addr = vma->vm_start;
|
|
unsigned long end = vma->vm_end;
|
|
|
|
/*
|
|
* Don't copy ptes where a page fault will fill them correctly.
|
|
* Fork becomes much lighter when there are big shared or private
|
|
* readonly mappings. The tradeoff is that copy_page_range is more
|
|
* efficient than faulting.
|
|
*/
|
|
if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_RESERVED))) {
|
|
if (!vma->anon_vma)
|
|
return 0;
|
|
}
|
|
|
|
if (is_vm_hugetlb_page(vma))
|
|
return copy_hugetlb_page_range(dst_mm, src_mm, vma);
|
|
|
|
dst_pgd = pgd_offset(dst_mm, addr);
|
|
src_pgd = pgd_offset(src_mm, addr);
|
|
do {
|
|
next = pgd_addr_end(addr, end);
|
|
if (pgd_none_or_clear_bad(src_pgd))
|
|
continue;
|
|
if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
|
|
vma, addr, next))
|
|
return -ENOMEM;
|
|
} while (dst_pgd++, src_pgd++, addr = next, addr != end);
|
|
return 0;
|
|
}
|
|
|
|
static void zap_pte_range(struct mmu_gather *tlb,
|
|
struct vm_area_struct *vma, pmd_t *pmd,
|
|
unsigned long addr, unsigned long end,
|
|
struct zap_details *details)
|
|
{
|
|
struct mm_struct *mm = tlb->mm;
|
|
pte_t *pte;
|
|
spinlock_t *ptl;
|
|
int file_rss = 0;
|
|
int anon_rss = 0;
|
|
|
|
pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
|
|
do {
|
|
pte_t ptent = *pte;
|
|
if (pte_none(ptent))
|
|
continue;
|
|
if (pte_present(ptent)) {
|
|
struct page *page = NULL;
|
|
if (!(vma->vm_flags & VM_RESERVED)) {
|
|
unsigned long pfn = pte_pfn(ptent);
|
|
if (unlikely(!pfn_valid(pfn)))
|
|
print_bad_pte(vma, ptent, addr);
|
|
else
|
|
page = pfn_to_page(pfn);
|
|
}
|
|
if (unlikely(details) && page) {
|
|
/*
|
|
* unmap_shared_mapping_pages() wants to
|
|
* invalidate cache without truncating:
|
|
* unmap shared but keep private pages.
|
|
*/
|
|
if (details->check_mapping &&
|
|
details->check_mapping != page->mapping)
|
|
continue;
|
|
/*
|
|
* Each page->index must be checked when
|
|
* invalidating or truncating nonlinear.
|
|
*/
|
|
if (details->nonlinear_vma &&
|
|
(page->index < details->first_index ||
|
|
page->index > details->last_index))
|
|
continue;
|
|
}
|
|
ptent = ptep_get_and_clear_full(mm, addr, pte,
|
|
tlb->fullmm);
|
|
tlb_remove_tlb_entry(tlb, pte, addr);
|
|
if (unlikely(!page))
|
|
continue;
|
|
if (unlikely(details) && details->nonlinear_vma
|
|
&& linear_page_index(details->nonlinear_vma,
|
|
addr) != page->index)
|
|
set_pte_at(mm, addr, pte,
|
|
pgoff_to_pte(page->index));
|
|
if (PageAnon(page))
|
|
anon_rss--;
|
|
else {
|
|
if (pte_dirty(ptent))
|
|
set_page_dirty(page);
|
|
if (pte_young(ptent))
|
|
mark_page_accessed(page);
|
|
file_rss--;
|
|
}
|
|
page_remove_rmap(page);
|
|
tlb_remove_page(tlb, page);
|
|
continue;
|
|
}
|
|
/*
|
|
* If details->check_mapping, we leave swap entries;
|
|
* if details->nonlinear_vma, we leave file entries.
|
|
*/
|
|
if (unlikely(details))
|
|
continue;
|
|
if (!pte_file(ptent))
|
|
free_swap_and_cache(pte_to_swp_entry(ptent));
|
|
pte_clear_full(mm, addr, pte, tlb->fullmm);
|
|
} while (pte++, addr += PAGE_SIZE, addr != end);
|
|
|
|
add_mm_rss(mm, file_rss, anon_rss);
|
|
pte_unmap_unlock(pte - 1, ptl);
|
|
}
|
|
|
|
static inline void zap_pmd_range(struct mmu_gather *tlb,
|
|
struct vm_area_struct *vma, pud_t *pud,
|
|
unsigned long addr, unsigned long end,
|
|
struct zap_details *details)
|
|
{
|
|
pmd_t *pmd;
|
|
unsigned long next;
|
|
|
|
pmd = pmd_offset(pud, addr);
|
|
do {
|
|
next = pmd_addr_end(addr, end);
|
|
if (pmd_none_or_clear_bad(pmd))
|
|
continue;
|
|
zap_pte_range(tlb, vma, pmd, addr, next, details);
|
|
} while (pmd++, addr = next, addr != end);
|
|
}
|
|
|
|
static inline void zap_pud_range(struct mmu_gather *tlb,
|
|
struct vm_area_struct *vma, pgd_t *pgd,
|
|
unsigned long addr, unsigned long end,
|
|
struct zap_details *details)
|
|
{
|
|
pud_t *pud;
|
|
unsigned long next;
|
|
|
|
pud = pud_offset(pgd, addr);
|
|
do {
|
|
next = pud_addr_end(addr, end);
|
|
if (pud_none_or_clear_bad(pud))
|
|
continue;
|
|
zap_pmd_range(tlb, vma, pud, addr, next, details);
|
|
} while (pud++, addr = next, addr != end);
|
|
}
|
|
|
|
static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
|
|
unsigned long addr, unsigned long end,
|
|
struct zap_details *details)
|
|
{
|
|
pgd_t *pgd;
|
|
unsigned long next;
|
|
|
|
if (details && !details->check_mapping && !details->nonlinear_vma)
|
|
details = NULL;
|
|
|
|
BUG_ON(addr >= end);
|
|
tlb_start_vma(tlb, vma);
|
|
pgd = pgd_offset(vma->vm_mm, addr);
|
|
do {
|
|
next = pgd_addr_end(addr, end);
|
|
if (pgd_none_or_clear_bad(pgd))
|
|
continue;
|
|
zap_pud_range(tlb, vma, pgd, addr, next, details);
|
|
} while (pgd++, addr = next, addr != end);
|
|
tlb_end_vma(tlb, vma);
|
|
}
|
|
|
|
#ifdef CONFIG_PREEMPT
|
|
# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
|
|
#else
|
|
/* No preempt: go for improved straight-line efficiency */
|
|
# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
|
|
#endif
|
|
|
|
/**
|
|
* unmap_vmas - unmap a range of memory covered by a list of vma's
|
|
* @tlbp: address of the caller's struct mmu_gather
|
|
* @vma: the starting vma
|
|
* @start_addr: virtual address at which to start unmapping
|
|
* @end_addr: virtual address at which to end unmapping
|
|
* @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
|
|
* @details: details of nonlinear truncation or shared cache invalidation
|
|
*
|
|
* Returns the end address of the unmapping (restart addr if interrupted).
|
|
*
|
|
* Unmap all pages in the vma list.
|
|
*
|
|
* We aim to not hold locks for too long (for scheduling latency reasons).
|
|
* So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
|
|
* return the ending mmu_gather to the caller.
|
|
*
|
|
* Only addresses between `start' and `end' will be unmapped.
|
|
*
|
|
* The VMA list must be sorted in ascending virtual address order.
|
|
*
|
|
* unmap_vmas() assumes that the caller will flush the whole unmapped address
|
|
* range after unmap_vmas() returns. So the only responsibility here is to
|
|
* ensure that any thus-far unmapped pages are flushed before unmap_vmas()
|
|
* drops the lock and schedules.
|
|
*/
|
|
unsigned long unmap_vmas(struct mmu_gather **tlbp,
|
|
struct vm_area_struct *vma, unsigned long start_addr,
|
|
unsigned long end_addr, unsigned long *nr_accounted,
|
|
struct zap_details *details)
|
|
{
|
|
unsigned long zap_bytes = ZAP_BLOCK_SIZE;
|
|
unsigned long tlb_start = 0; /* For tlb_finish_mmu */
|
|
int tlb_start_valid = 0;
|
|
unsigned long start = start_addr;
|
|
spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
|
|
int fullmm = (*tlbp)->fullmm;
|
|
|
|
for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
|
|
unsigned long end;
|
|
|
|
start = max(vma->vm_start, start_addr);
|
|
if (start >= vma->vm_end)
|
|
continue;
|
|
end = min(vma->vm_end, end_addr);
|
|
if (end <= vma->vm_start)
|
|
continue;
|
|
|
|
if (vma->vm_flags & VM_ACCOUNT)
|
|
*nr_accounted += (end - start) >> PAGE_SHIFT;
|
|
|
|
while (start != end) {
|
|
unsigned long block;
|
|
|
|
if (!tlb_start_valid) {
|
|
tlb_start = start;
|
|
tlb_start_valid = 1;
|
|
}
|
|
|
|
if (is_vm_hugetlb_page(vma)) {
|
|
block = end - start;
|
|
unmap_hugepage_range(vma, start, end);
|
|
} else {
|
|
block = min(zap_bytes, end - start);
|
|
unmap_page_range(*tlbp, vma, start,
|
|
start + block, details);
|
|
}
|
|
|
|
start += block;
|
|
zap_bytes -= block;
|
|
if ((long)zap_bytes > 0)
|
|
continue;
|
|
|
|
tlb_finish_mmu(*tlbp, tlb_start, start);
|
|
|
|
if (need_resched() ||
|
|
(i_mmap_lock && need_lockbreak(i_mmap_lock))) {
|
|
if (i_mmap_lock) {
|
|
*tlbp = NULL;
|
|
goto out;
|
|
}
|
|
cond_resched();
|
|
}
|
|
|
|
*tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
|
|
tlb_start_valid = 0;
|
|
zap_bytes = ZAP_BLOCK_SIZE;
|
|
}
|
|
}
|
|
out:
|
|
return start; /* which is now the end (or restart) address */
|
|
}
|
|
|
|
/**
|
|
* zap_page_range - remove user pages in a given range
|
|
* @vma: vm_area_struct holding the applicable pages
|
|
* @address: starting address of pages to zap
|
|
* @size: number of bytes to zap
|
|
* @details: details of nonlinear truncation or shared cache invalidation
|
|
*/
|
|
unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
|
|
unsigned long size, struct zap_details *details)
|
|
{
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
struct mmu_gather *tlb;
|
|
unsigned long end = address + size;
|
|
unsigned long nr_accounted = 0;
|
|
|
|
lru_add_drain();
|
|
tlb = tlb_gather_mmu(mm, 0);
|
|
update_hiwater_rss(mm);
|
|
end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
|
|
if (tlb)
|
|
tlb_finish_mmu(tlb, address, end);
|
|
return end;
|
|
}
|
|
|
|
/*
|
|
* Do a quick page-table lookup for a single page.
|
|
*/
|
|
struct page *follow_page(struct mm_struct *mm, unsigned long address,
|
|
unsigned int flags)
|
|
{
|
|
pgd_t *pgd;
|
|
pud_t *pud;
|
|
pmd_t *pmd;
|
|
pte_t *ptep, pte;
|
|
spinlock_t *ptl;
|
|
unsigned long pfn;
|
|
struct page *page;
|
|
|
|
page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
|
|
if (!IS_ERR(page)) {
|
|
BUG_ON(flags & FOLL_GET);
|
|
goto out;
|
|
}
|
|
|
|
page = NULL;
|
|
pgd = pgd_offset(mm, address);
|
|
if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
|
|
goto no_page_table;
|
|
|
|
pud = pud_offset(pgd, address);
|
|
if (pud_none(*pud) || unlikely(pud_bad(*pud)))
|
|
goto no_page_table;
|
|
|
|
pmd = pmd_offset(pud, address);
|
|
if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
|
|
goto no_page_table;
|
|
|
|
if (pmd_huge(*pmd)) {
|
|
BUG_ON(flags & FOLL_GET);
|
|
page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
|
|
goto out;
|
|
}
|
|
|
|
ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
|
|
if (!ptep)
|
|
goto out;
|
|
|
|
pte = *ptep;
|
|
if (!pte_present(pte))
|
|
goto unlock;
|
|
if ((flags & FOLL_WRITE) && !pte_write(pte))
|
|
goto unlock;
|
|
pfn = pte_pfn(pte);
|
|
if (!pfn_valid(pfn))
|
|
goto unlock;
|
|
|
|
page = pfn_to_page(pfn);
|
|
if (flags & FOLL_GET)
|
|
get_page(page);
|
|
if (flags & FOLL_TOUCH) {
|
|
if ((flags & FOLL_WRITE) &&
|
|
!pte_dirty(pte) && !PageDirty(page))
|
|
set_page_dirty(page);
|
|
mark_page_accessed(page);
|
|
}
|
|
unlock:
|
|
pte_unmap_unlock(ptep, ptl);
|
|
out:
|
|
return page;
|
|
|
|
no_page_table:
|
|
/*
|
|
* When core dumping an enormous anonymous area that nobody
|
|
* has touched so far, we don't want to allocate page tables.
|
|
*/
|
|
if (flags & FOLL_ANON) {
|
|
page = ZERO_PAGE(address);
|
|
if (flags & FOLL_GET)
|
|
get_page(page);
|
|
BUG_ON(flags & FOLL_WRITE);
|
|
}
|
|
return page;
|
|
}
|
|
|
|
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
|
|
unsigned long start, int len, int write, int force,
|
|
struct page **pages, struct vm_area_struct **vmas)
|
|
{
|
|
int i;
|
|
unsigned int vm_flags;
|
|
|
|
/*
|
|
* Require read or write permissions.
|
|
* If 'force' is set, we only require the "MAY" flags.
|
|
*/
|
|
vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
|
|
vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
|
|
i = 0;
|
|
|
|
do {
|
|
struct vm_area_struct *vma;
|
|
unsigned int foll_flags;
|
|
|
|
vma = find_extend_vma(mm, start);
|
|
if (!vma && in_gate_area(tsk, start)) {
|
|
unsigned long pg = start & PAGE_MASK;
|
|
struct vm_area_struct *gate_vma = get_gate_vma(tsk);
|
|
pgd_t *pgd;
|
|
pud_t *pud;
|
|
pmd_t *pmd;
|
|
pte_t *pte;
|
|
if (write) /* user gate pages are read-only */
|
|
return i ? : -EFAULT;
|
|
if (pg > TASK_SIZE)
|
|
pgd = pgd_offset_k(pg);
|
|
else
|
|
pgd = pgd_offset_gate(mm, pg);
|
|
BUG_ON(pgd_none(*pgd));
|
|
pud = pud_offset(pgd, pg);
|
|
BUG_ON(pud_none(*pud));
|
|
pmd = pmd_offset(pud, pg);
|
|
if (pmd_none(*pmd))
|
|
return i ? : -EFAULT;
|
|
pte = pte_offset_map(pmd, pg);
|
|
if (pte_none(*pte)) {
|
|
pte_unmap(pte);
|
|
return i ? : -EFAULT;
|
|
}
|
|
if (pages) {
|
|
pages[i] = pte_page(*pte);
|
|
get_page(pages[i]);
|
|
}
|
|
pte_unmap(pte);
|
|
if (vmas)
|
|
vmas[i] = gate_vma;
|
|
i++;
|
|
start += PAGE_SIZE;
|
|
len--;
|
|
continue;
|
|
}
|
|
|
|
if (!vma || (vma->vm_flags & (VM_IO | VM_RESERVED))
|
|
|| !(vm_flags & vma->vm_flags))
|
|
return i ? : -EFAULT;
|
|
|
|
if (is_vm_hugetlb_page(vma)) {
|
|
i = follow_hugetlb_page(mm, vma, pages, vmas,
|
|
&start, &len, i);
|
|
continue;
|
|
}
|
|
|
|
foll_flags = FOLL_TOUCH;
|
|
if (pages)
|
|
foll_flags |= FOLL_GET;
|
|
if (!write && !(vma->vm_flags & VM_LOCKED) &&
|
|
(!vma->vm_ops || !vma->vm_ops->nopage))
|
|
foll_flags |= FOLL_ANON;
|
|
|
|
do {
|
|
struct page *page;
|
|
|
|
if (write)
|
|
foll_flags |= FOLL_WRITE;
|
|
|
|
cond_resched();
|
|
while (!(page = follow_page(mm, start, foll_flags))) {
|
|
int ret;
|
|
ret = __handle_mm_fault(mm, vma, start,
|
|
foll_flags & FOLL_WRITE);
|
|
/*
|
|
* The VM_FAULT_WRITE bit tells us that do_wp_page has
|
|
* broken COW when necessary, even if maybe_mkwrite
|
|
* decided not to set pte_write. We can thus safely do
|
|
* subsequent page lookups as if they were reads.
|
|
*/
|
|
if (ret & VM_FAULT_WRITE)
|
|
foll_flags &= ~FOLL_WRITE;
|
|
|
|
switch (ret & ~VM_FAULT_WRITE) {
|
|
case VM_FAULT_MINOR:
|
|
tsk->min_flt++;
|
|
break;
|
|
case VM_FAULT_MAJOR:
|
|
tsk->maj_flt++;
|
|
break;
|
|
case VM_FAULT_SIGBUS:
|
|
return i ? i : -EFAULT;
|
|
case VM_FAULT_OOM:
|
|
return i ? i : -ENOMEM;
|
|
default:
|
|
BUG();
|
|
}
|
|
}
|
|
if (pages) {
|
|
pages[i] = page;
|
|
flush_dcache_page(page);
|
|
}
|
|
if (vmas)
|
|
vmas[i] = vma;
|
|
i++;
|
|
start += PAGE_SIZE;
|
|
len--;
|
|
} while (len && start < vma->vm_end);
|
|
} while (len);
|
|
return i;
|
|
}
|
|
EXPORT_SYMBOL(get_user_pages);
|
|
|
|
static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
|
|
unsigned long addr, unsigned long end, pgprot_t prot)
|
|
{
|
|
pte_t *pte;
|
|
spinlock_t *ptl;
|
|
|
|
pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
|
|
if (!pte)
|
|
return -ENOMEM;
|
|
do {
|
|
struct page *page = ZERO_PAGE(addr);
|
|
pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
|
|
page_cache_get(page);
|
|
page_add_file_rmap(page);
|
|
inc_mm_counter(mm, file_rss);
|
|
BUG_ON(!pte_none(*pte));
|
|
set_pte_at(mm, addr, pte, zero_pte);
|
|
} while (pte++, addr += PAGE_SIZE, addr != end);
|
|
pte_unmap_unlock(pte - 1, ptl);
|
|
return 0;
|
|
}
|
|
|
|
static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
|
|
unsigned long addr, unsigned long end, pgprot_t prot)
|
|
{
|
|
pmd_t *pmd;
|
|
unsigned long next;
|
|
|
|
pmd = pmd_alloc(mm, pud, addr);
|
|
if (!pmd)
|
|
return -ENOMEM;
|
|
do {
|
|
next = pmd_addr_end(addr, end);
|
|
if (zeromap_pte_range(mm, pmd, addr, next, prot))
|
|
return -ENOMEM;
|
|
} while (pmd++, addr = next, addr != end);
|
|
return 0;
|
|
}
|
|
|
|
static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
|
|
unsigned long addr, unsigned long end, pgprot_t prot)
|
|
{
|
|
pud_t *pud;
|
|
unsigned long next;
|
|
|
|
pud = pud_alloc(mm, pgd, addr);
|
|
if (!pud)
|
|
return -ENOMEM;
|
|
do {
|
|
next = pud_addr_end(addr, end);
|
|
if (zeromap_pmd_range(mm, pud, addr, next, prot))
|
|
return -ENOMEM;
|
|
} while (pud++, addr = next, addr != end);
|
|
return 0;
|
|
}
|
|
|
|
int zeromap_page_range(struct vm_area_struct *vma,
|
|
unsigned long addr, unsigned long size, pgprot_t prot)
|
|
{
|
|
pgd_t *pgd;
|
|
unsigned long next;
|
|
unsigned long end = addr + size;
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
int err;
|
|
|
|
BUG_ON(addr >= end);
|
|
pgd = pgd_offset(mm, addr);
|
|
flush_cache_range(vma, addr, end);
|
|
do {
|
|
next = pgd_addr_end(addr, end);
|
|
err = zeromap_pud_range(mm, pgd, addr, next, prot);
|
|
if (err)
|
|
break;
|
|
} while (pgd++, addr = next, addr != end);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* maps a range of physical memory into the requested pages. the old
|
|
* mappings are removed. any references to nonexistent pages results
|
|
* in null mappings (currently treated as "copy-on-access")
|
|
*/
|
|
static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
|
|
unsigned long addr, unsigned long end,
|
|
unsigned long pfn, pgprot_t prot)
|
|
{
|
|
pte_t *pte;
|
|
spinlock_t *ptl;
|
|
|
|
pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
|
|
if (!pte)
|
|
return -ENOMEM;
|
|
do {
|
|
BUG_ON(!pte_none(*pte));
|
|
set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
|
|
pfn++;
|
|
} while (pte++, addr += PAGE_SIZE, addr != end);
|
|
pte_unmap_unlock(pte - 1, ptl);
|
|
return 0;
|
|
}
|
|
|
|
static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
|
|
unsigned long addr, unsigned long end,
|
|
unsigned long pfn, pgprot_t prot)
|
|
{
|
|
pmd_t *pmd;
|
|
unsigned long next;
|
|
|
|
pfn -= addr >> PAGE_SHIFT;
|
|
pmd = pmd_alloc(mm, pud, addr);
|
|
if (!pmd)
|
|
return -ENOMEM;
|
|
do {
|
|
next = pmd_addr_end(addr, end);
|
|
if (remap_pte_range(mm, pmd, addr, next,
|
|
pfn + (addr >> PAGE_SHIFT), prot))
|
|
return -ENOMEM;
|
|
} while (pmd++, addr = next, addr != end);
|
|
return 0;
|
|
}
|
|
|
|
static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
|
|
unsigned long addr, unsigned long end,
|
|
unsigned long pfn, pgprot_t prot)
|
|
{
|
|
pud_t *pud;
|
|
unsigned long next;
|
|
|
|
pfn -= addr >> PAGE_SHIFT;
|
|
pud = pud_alloc(mm, pgd, addr);
|
|
if (!pud)
|
|
return -ENOMEM;
|
|
do {
|
|
next = pud_addr_end(addr, end);
|
|
if (remap_pmd_range(mm, pud, addr, next,
|
|
pfn + (addr >> PAGE_SHIFT), prot))
|
|
return -ENOMEM;
|
|
} while (pud++, addr = next, addr != end);
|
|
return 0;
|
|
}
|
|
|
|
/* Note: this is only safe if the mm semaphore is held when called. */
|
|
int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
|
|
unsigned long pfn, unsigned long size, pgprot_t prot)
|
|
{
|
|
pgd_t *pgd;
|
|
unsigned long next;
|
|
unsigned long end = addr + PAGE_ALIGN(size);
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
int err;
|
|
|
|
/*
|
|
* Physically remapped pages are special. Tell the
|
|
* rest of the world about it:
|
|
* VM_IO tells people not to look at these pages
|
|
* (accesses can have side effects).
|
|
* VM_RESERVED tells the core MM not to "manage" these pages
|
|
* (e.g. refcount, mapcount, try to swap them out).
|
|
*/
|
|
vma->vm_flags |= VM_IO | VM_RESERVED;
|
|
|
|
BUG_ON(addr >= end);
|
|
pfn -= addr >> PAGE_SHIFT;
|
|
pgd = pgd_offset(mm, addr);
|
|
flush_cache_range(vma, addr, end);
|
|
do {
|
|
next = pgd_addr_end(addr, end);
|
|
err = remap_pud_range(mm, pgd, addr, next,
|
|
pfn + (addr >> PAGE_SHIFT), prot);
|
|
if (err)
|
|
break;
|
|
} while (pgd++, addr = next, addr != end);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL(remap_pfn_range);
|
|
|
|
/*
|
|
* handle_pte_fault chooses page fault handler according to an entry
|
|
* which was read non-atomically. Before making any commitment, on
|
|
* those architectures or configurations (e.g. i386 with PAE) which
|
|
* might give a mix of unmatched parts, do_swap_page and do_file_page
|
|
* must check under lock before unmapping the pte and proceeding
|
|
* (but do_wp_page is only called after already making such a check;
|
|
* and do_anonymous_page and do_no_page can safely check later on).
|
|
*/
|
|
static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
|
|
pte_t *page_table, pte_t orig_pte)
|
|
{
|
|
int same = 1;
|
|
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
|
|
if (sizeof(pte_t) > sizeof(unsigned long)) {
|
|
spinlock_t *ptl = pte_lockptr(mm, pmd);
|
|
spin_lock(ptl);
|
|
same = pte_same(*page_table, orig_pte);
|
|
spin_unlock(ptl);
|
|
}
|
|
#endif
|
|
pte_unmap(page_table);
|
|
return same;
|
|
}
|
|
|
|
/*
|
|
* Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
|
|
* servicing faults for write access. In the normal case, do always want
|
|
* pte_mkwrite. But get_user_pages can cause write faults for mappings
|
|
* that do not have writing enabled, when used by access_process_vm.
|
|
*/
|
|
static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
|
|
{
|
|
if (likely(vma->vm_flags & VM_WRITE))
|
|
pte = pte_mkwrite(pte);
|
|
return pte;
|
|
}
|
|
|
|
/*
|
|
* This routine handles present pages, when users try to write
|
|
* to a shared page. It is done by copying the page to a new address
|
|
* and decrementing the shared-page counter for the old page.
|
|
*
|
|
* Note that this routine assumes that the protection checks have been
|
|
* done by the caller (the low-level page fault routine in most cases).
|
|
* Thus we can safely just mark it writable once we've done any necessary
|
|
* COW.
|
|
*
|
|
* We also mark the page dirty at this point even though the page will
|
|
* change only once the write actually happens. This avoids a few races,
|
|
* and potentially makes it more efficient.
|
|
*
|
|
* We enter with non-exclusive mmap_sem (to exclude vma changes,
|
|
* but allow concurrent faults), with pte both mapped and locked.
|
|
* We return with mmap_sem still held, but pte unmapped and unlocked.
|
|
*/
|
|
static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *page_table, pmd_t *pmd,
|
|
spinlock_t *ptl, pte_t orig_pte)
|
|
{
|
|
struct page *old_page, *new_page;
|
|
unsigned long pfn = pte_pfn(orig_pte);
|
|
pte_t entry;
|
|
int ret = VM_FAULT_MINOR;
|
|
|
|
BUG_ON(vma->vm_flags & VM_RESERVED);
|
|
|
|
if (unlikely(!pfn_valid(pfn))) {
|
|
/*
|
|
* Page table corrupted: show pte and kill process.
|
|
*/
|
|
print_bad_pte(vma, orig_pte, address);
|
|
ret = VM_FAULT_OOM;
|
|
goto unlock;
|
|
}
|
|
old_page = pfn_to_page(pfn);
|
|
|
|
if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
|
|
int reuse = can_share_swap_page(old_page);
|
|
unlock_page(old_page);
|
|
if (reuse) {
|
|
flush_cache_page(vma, address, pfn);
|
|
entry = pte_mkyoung(orig_pte);
|
|
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
|
|
ptep_set_access_flags(vma, address, page_table, entry, 1);
|
|
update_mmu_cache(vma, address, entry);
|
|
lazy_mmu_prot_update(entry);
|
|
ret |= VM_FAULT_WRITE;
|
|
goto unlock;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Ok, we need to copy. Oh, well..
|
|
*/
|
|
page_cache_get(old_page);
|
|
pte_unmap_unlock(page_table, ptl);
|
|
|
|
if (unlikely(anon_vma_prepare(vma)))
|
|
goto oom;
|
|
if (old_page == ZERO_PAGE(address)) {
|
|
new_page = alloc_zeroed_user_highpage(vma, address);
|
|
if (!new_page)
|
|
goto oom;
|
|
} else {
|
|
new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
|
|
if (!new_page)
|
|
goto oom;
|
|
copy_user_highpage(new_page, old_page, address);
|
|
}
|
|
|
|
/*
|
|
* Re-check the pte - we dropped the lock
|
|
*/
|
|
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
|
|
if (likely(pte_same(*page_table, orig_pte))) {
|
|
page_remove_rmap(old_page);
|
|
if (!PageAnon(old_page)) {
|
|
inc_mm_counter(mm, anon_rss);
|
|
dec_mm_counter(mm, file_rss);
|
|
}
|
|
flush_cache_page(vma, address, pfn);
|
|
entry = mk_pte(new_page, vma->vm_page_prot);
|
|
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
|
|
ptep_establish(vma, address, page_table, entry);
|
|
update_mmu_cache(vma, address, entry);
|
|
lazy_mmu_prot_update(entry);
|
|
lru_cache_add_active(new_page);
|
|
page_add_anon_rmap(new_page, vma, address);
|
|
|
|
/* Free the old page.. */
|
|
new_page = old_page;
|
|
ret |= VM_FAULT_WRITE;
|
|
}
|
|
page_cache_release(new_page);
|
|
page_cache_release(old_page);
|
|
unlock:
|
|
pte_unmap_unlock(page_table, ptl);
|
|
return ret;
|
|
oom:
|
|
page_cache_release(old_page);
|
|
return VM_FAULT_OOM;
|
|
}
|
|
|
|
/*
|
|
* Helper functions for unmap_mapping_range().
|
|
*
|
|
* __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
|
|
*
|
|
* We have to restart searching the prio_tree whenever we drop the lock,
|
|
* since the iterator is only valid while the lock is held, and anyway
|
|
* a later vma might be split and reinserted earlier while lock dropped.
|
|
*
|
|
* The list of nonlinear vmas could be handled more efficiently, using
|
|
* a placeholder, but handle it in the same way until a need is shown.
|
|
* It is important to search the prio_tree before nonlinear list: a vma
|
|
* may become nonlinear and be shifted from prio_tree to nonlinear list
|
|
* while the lock is dropped; but never shifted from list to prio_tree.
|
|
*
|
|
* In order to make forward progress despite restarting the search,
|
|
* vm_truncate_count is used to mark a vma as now dealt with, so we can
|
|
* quickly skip it next time around. Since the prio_tree search only
|
|
* shows us those vmas affected by unmapping the range in question, we
|
|
* can't efficiently keep all vmas in step with mapping->truncate_count:
|
|
* so instead reset them all whenever it wraps back to 0 (then go to 1).
|
|
* mapping->truncate_count and vma->vm_truncate_count are protected by
|
|
* i_mmap_lock.
|
|
*
|
|
* In order to make forward progress despite repeatedly restarting some
|
|
* large vma, note the restart_addr from unmap_vmas when it breaks out:
|
|
* and restart from that address when we reach that vma again. It might
|
|
* have been split or merged, shrunk or extended, but never shifted: so
|
|
* restart_addr remains valid so long as it remains in the vma's range.
|
|
* unmap_mapping_range forces truncate_count to leap over page-aligned
|
|
* values so we can save vma's restart_addr in its truncate_count field.
|
|
*/
|
|
#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
|
|
|
|
static void reset_vma_truncate_counts(struct address_space *mapping)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
struct prio_tree_iter iter;
|
|
|
|
vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
|
|
vma->vm_truncate_count = 0;
|
|
list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
|
|
vma->vm_truncate_count = 0;
|
|
}
|
|
|
|
static int unmap_mapping_range_vma(struct vm_area_struct *vma,
|
|
unsigned long start_addr, unsigned long end_addr,
|
|
struct zap_details *details)
|
|
{
|
|
unsigned long restart_addr;
|
|
int need_break;
|
|
|
|
again:
|
|
restart_addr = vma->vm_truncate_count;
|
|
if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
|
|
start_addr = restart_addr;
|
|
if (start_addr >= end_addr) {
|
|
/* Top of vma has been split off since last time */
|
|
vma->vm_truncate_count = details->truncate_count;
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
restart_addr = zap_page_range(vma, start_addr,
|
|
end_addr - start_addr, details);
|
|
need_break = need_resched() ||
|
|
need_lockbreak(details->i_mmap_lock);
|
|
|
|
if (restart_addr >= end_addr) {
|
|
/* We have now completed this vma: mark it so */
|
|
vma->vm_truncate_count = details->truncate_count;
|
|
if (!need_break)
|
|
return 0;
|
|
} else {
|
|
/* Note restart_addr in vma's truncate_count field */
|
|
vma->vm_truncate_count = restart_addr;
|
|
if (!need_break)
|
|
goto again;
|
|
}
|
|
|
|
spin_unlock(details->i_mmap_lock);
|
|
cond_resched();
|
|
spin_lock(details->i_mmap_lock);
|
|
return -EINTR;
|
|
}
|
|
|
|
static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
|
|
struct zap_details *details)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
struct prio_tree_iter iter;
|
|
pgoff_t vba, vea, zba, zea;
|
|
|
|
restart:
|
|
vma_prio_tree_foreach(vma, &iter, root,
|
|
details->first_index, details->last_index) {
|
|
/* Skip quickly over those we have already dealt with */
|
|
if (vma->vm_truncate_count == details->truncate_count)
|
|
continue;
|
|
|
|
vba = vma->vm_pgoff;
|
|
vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
|
|
/* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
|
|
zba = details->first_index;
|
|
if (zba < vba)
|
|
zba = vba;
|
|
zea = details->last_index;
|
|
if (zea > vea)
|
|
zea = vea;
|
|
|
|
if (unmap_mapping_range_vma(vma,
|
|
((zba - vba) << PAGE_SHIFT) + vma->vm_start,
|
|
((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
|
|
details) < 0)
|
|
goto restart;
|
|
}
|
|
}
|
|
|
|
static inline void unmap_mapping_range_list(struct list_head *head,
|
|
struct zap_details *details)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
|
|
/*
|
|
* In nonlinear VMAs there is no correspondence between virtual address
|
|
* offset and file offset. So we must perform an exhaustive search
|
|
* across *all* the pages in each nonlinear VMA, not just the pages
|
|
* whose virtual address lies outside the file truncation point.
|
|
*/
|
|
restart:
|
|
list_for_each_entry(vma, head, shared.vm_set.list) {
|
|
/* Skip quickly over those we have already dealt with */
|
|
if (vma->vm_truncate_count == details->truncate_count)
|
|
continue;
|
|
details->nonlinear_vma = vma;
|
|
if (unmap_mapping_range_vma(vma, vma->vm_start,
|
|
vma->vm_end, details) < 0)
|
|
goto restart;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* unmap_mapping_range - unmap the portion of all mmaps
|
|
* in the specified address_space corresponding to the specified
|
|
* page range in the underlying file.
|
|
* @mapping: the address space containing mmaps to be unmapped.
|
|
* @holebegin: byte in first page to unmap, relative to the start of
|
|
* the underlying file. This will be rounded down to a PAGE_SIZE
|
|
* boundary. Note that this is different from vmtruncate(), which
|
|
* must keep the partial page. In contrast, we must get rid of
|
|
* partial pages.
|
|
* @holelen: size of prospective hole in bytes. This will be rounded
|
|
* up to a PAGE_SIZE boundary. A holelen of zero truncates to the
|
|
* end of the file.
|
|
* @even_cows: 1 when truncating a file, unmap even private COWed pages;
|
|
* but 0 when invalidating pagecache, don't throw away private data.
|
|
*/
|
|
void unmap_mapping_range(struct address_space *mapping,
|
|
loff_t const holebegin, loff_t const holelen, int even_cows)
|
|
{
|
|
struct zap_details details;
|
|
pgoff_t hba = holebegin >> PAGE_SHIFT;
|
|
pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
|
|
/* Check for overflow. */
|
|
if (sizeof(holelen) > sizeof(hlen)) {
|
|
long long holeend =
|
|
(holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
if (holeend & ~(long long)ULONG_MAX)
|
|
hlen = ULONG_MAX - hba + 1;
|
|
}
|
|
|
|
details.check_mapping = even_cows? NULL: mapping;
|
|
details.nonlinear_vma = NULL;
|
|
details.first_index = hba;
|
|
details.last_index = hba + hlen - 1;
|
|
if (details.last_index < details.first_index)
|
|
details.last_index = ULONG_MAX;
|
|
details.i_mmap_lock = &mapping->i_mmap_lock;
|
|
|
|
spin_lock(&mapping->i_mmap_lock);
|
|
|
|
/* serialize i_size write against truncate_count write */
|
|
smp_wmb();
|
|
/* Protect against page faults, and endless unmapping loops */
|
|
mapping->truncate_count++;
|
|
/*
|
|
* For archs where spin_lock has inclusive semantics like ia64
|
|
* this smp_mb() will prevent to read pagetable contents
|
|
* before the truncate_count increment is visible to
|
|
* other cpus.
|
|
*/
|
|
smp_mb();
|
|
if (unlikely(is_restart_addr(mapping->truncate_count))) {
|
|
if (mapping->truncate_count == 0)
|
|
reset_vma_truncate_counts(mapping);
|
|
mapping->truncate_count++;
|
|
}
|
|
details.truncate_count = mapping->truncate_count;
|
|
|
|
if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
|
|
unmap_mapping_range_tree(&mapping->i_mmap, &details);
|
|
if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
|
|
unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
|
|
spin_unlock(&mapping->i_mmap_lock);
|
|
}
|
|
EXPORT_SYMBOL(unmap_mapping_range);
|
|
|
|
/*
|
|
* Handle all mappings that got truncated by a "truncate()"
|
|
* system call.
|
|
*
|
|
* NOTE! We have to be ready to update the memory sharing
|
|
* between the file and the memory map for a potential last
|
|
* incomplete page. Ugly, but necessary.
|
|
*/
|
|
int vmtruncate(struct inode * inode, loff_t offset)
|
|
{
|
|
struct address_space *mapping = inode->i_mapping;
|
|
unsigned long limit;
|
|
|
|
if (inode->i_size < offset)
|
|
goto do_expand;
|
|
/*
|
|
* truncation of in-use swapfiles is disallowed - it would cause
|
|
* subsequent swapout to scribble on the now-freed blocks.
|
|
*/
|
|
if (IS_SWAPFILE(inode))
|
|
goto out_busy;
|
|
i_size_write(inode, offset);
|
|
unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
|
|
truncate_inode_pages(mapping, offset);
|
|
goto out_truncate;
|
|
|
|
do_expand:
|
|
limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
|
|
if (limit != RLIM_INFINITY && offset > limit)
|
|
goto out_sig;
|
|
if (offset > inode->i_sb->s_maxbytes)
|
|
goto out_big;
|
|
i_size_write(inode, offset);
|
|
|
|
out_truncate:
|
|
if (inode->i_op && inode->i_op->truncate)
|
|
inode->i_op->truncate(inode);
|
|
return 0;
|
|
out_sig:
|
|
send_sig(SIGXFSZ, current, 0);
|
|
out_big:
|
|
return -EFBIG;
|
|
out_busy:
|
|
return -ETXTBSY;
|
|
}
|
|
|
|
EXPORT_SYMBOL(vmtruncate);
|
|
|
|
/*
|
|
* Primitive swap readahead code. We simply read an aligned block of
|
|
* (1 << page_cluster) entries in the swap area. This method is chosen
|
|
* because it doesn't cost us any seek time. We also make sure to queue
|
|
* the 'original' request together with the readahead ones...
|
|
*
|
|
* This has been extended to use the NUMA policies from the mm triggering
|
|
* the readahead.
|
|
*
|
|
* Caller must hold down_read on the vma->vm_mm if vma is not NULL.
|
|
*/
|
|
void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
|
|
{
|
|
#ifdef CONFIG_NUMA
|
|
struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
|
|
#endif
|
|
int i, num;
|
|
struct page *new_page;
|
|
unsigned long offset;
|
|
|
|
/*
|
|
* Get the number of handles we should do readahead io to.
|
|
*/
|
|
num = valid_swaphandles(entry, &offset);
|
|
for (i = 0; i < num; offset++, i++) {
|
|
/* Ok, do the async read-ahead now */
|
|
new_page = read_swap_cache_async(swp_entry(swp_type(entry),
|
|
offset), vma, addr);
|
|
if (!new_page)
|
|
break;
|
|
page_cache_release(new_page);
|
|
#ifdef CONFIG_NUMA
|
|
/*
|
|
* Find the next applicable VMA for the NUMA policy.
|
|
*/
|
|
addr += PAGE_SIZE;
|
|
if (addr == 0)
|
|
vma = NULL;
|
|
if (vma) {
|
|
if (addr >= vma->vm_end) {
|
|
vma = next_vma;
|
|
next_vma = vma ? vma->vm_next : NULL;
|
|
}
|
|
if (vma && addr < vma->vm_start)
|
|
vma = NULL;
|
|
} else {
|
|
if (next_vma && addr >= next_vma->vm_start) {
|
|
vma = next_vma;
|
|
next_vma = vma->vm_next;
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
lru_add_drain(); /* Push any new pages onto the LRU now */
|
|
}
|
|
|
|
/*
|
|
* We enter with non-exclusive mmap_sem (to exclude vma changes,
|
|
* but allow concurrent faults), and pte mapped but not yet locked.
|
|
* We return with mmap_sem still held, but pte unmapped and unlocked.
|
|
*/
|
|
static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *page_table, pmd_t *pmd,
|
|
int write_access, pte_t orig_pte)
|
|
{
|
|
spinlock_t *ptl;
|
|
struct page *page;
|
|
swp_entry_t entry;
|
|
pte_t pte;
|
|
int ret = VM_FAULT_MINOR;
|
|
|
|
if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
|
|
goto out;
|
|
|
|
entry = pte_to_swp_entry(orig_pte);
|
|
page = lookup_swap_cache(entry);
|
|
if (!page) {
|
|
swapin_readahead(entry, address, vma);
|
|
page = read_swap_cache_async(entry, vma, address);
|
|
if (!page) {
|
|
/*
|
|
* Back out if somebody else faulted in this pte
|
|
* while we released the pte lock.
|
|
*/
|
|
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
|
|
if (likely(pte_same(*page_table, orig_pte)))
|
|
ret = VM_FAULT_OOM;
|
|
goto unlock;
|
|
}
|
|
|
|
/* Had to read the page from swap area: Major fault */
|
|
ret = VM_FAULT_MAJOR;
|
|
inc_page_state(pgmajfault);
|
|
grab_swap_token();
|
|
}
|
|
|
|
mark_page_accessed(page);
|
|
lock_page(page);
|
|
|
|
/*
|
|
* Back out if somebody else already faulted in this pte.
|
|
*/
|
|
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
|
|
if (unlikely(!pte_same(*page_table, orig_pte)))
|
|
goto out_nomap;
|
|
|
|
if (unlikely(!PageUptodate(page))) {
|
|
ret = VM_FAULT_SIGBUS;
|
|
goto out_nomap;
|
|
}
|
|
|
|
/* The page isn't present yet, go ahead with the fault. */
|
|
|
|
inc_mm_counter(mm, anon_rss);
|
|
pte = mk_pte(page, vma->vm_page_prot);
|
|
if (write_access && can_share_swap_page(page)) {
|
|
pte = maybe_mkwrite(pte_mkdirty(pte), vma);
|
|
write_access = 0;
|
|
}
|
|
|
|
flush_icache_page(vma, page);
|
|
set_pte_at(mm, address, page_table, pte);
|
|
page_add_anon_rmap(page, vma, address);
|
|
|
|
swap_free(entry);
|
|
if (vm_swap_full())
|
|
remove_exclusive_swap_page(page);
|
|
unlock_page(page);
|
|
|
|
if (write_access) {
|
|
if (do_wp_page(mm, vma, address,
|
|
page_table, pmd, ptl, pte) == VM_FAULT_OOM)
|
|
ret = VM_FAULT_OOM;
|
|
goto out;
|
|
}
|
|
|
|
/* No need to invalidate - it was non-present before */
|
|
update_mmu_cache(vma, address, pte);
|
|
lazy_mmu_prot_update(pte);
|
|
unlock:
|
|
pte_unmap_unlock(page_table, ptl);
|
|
out:
|
|
return ret;
|
|
out_nomap:
|
|
pte_unmap_unlock(page_table, ptl);
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* We enter with non-exclusive mmap_sem (to exclude vma changes,
|
|
* but allow concurrent faults), and pte mapped but not yet locked.
|
|
* We return with mmap_sem still held, but pte unmapped and unlocked.
|
|
*/
|
|
static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *page_table, pmd_t *pmd,
|
|
int write_access)
|
|
{
|
|
struct page *page;
|
|
spinlock_t *ptl;
|
|
pte_t entry;
|
|
|
|
if (write_access) {
|
|
/* Allocate our own private page. */
|
|
pte_unmap(page_table);
|
|
|
|
if (unlikely(anon_vma_prepare(vma)))
|
|
goto oom;
|
|
page = alloc_zeroed_user_highpage(vma, address);
|
|
if (!page)
|
|
goto oom;
|
|
|
|
entry = mk_pte(page, vma->vm_page_prot);
|
|
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
|
|
|
|
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
|
|
if (!pte_none(*page_table))
|
|
goto release;
|
|
inc_mm_counter(mm, anon_rss);
|
|
lru_cache_add_active(page);
|
|
SetPageReferenced(page);
|
|
page_add_anon_rmap(page, vma, address);
|
|
} else {
|
|
/* Map the ZERO_PAGE - vm_page_prot is readonly */
|
|
page = ZERO_PAGE(address);
|
|
page_cache_get(page);
|
|
entry = mk_pte(page, vma->vm_page_prot);
|
|
|
|
ptl = pte_lockptr(mm, pmd);
|
|
spin_lock(ptl);
|
|
if (!pte_none(*page_table))
|
|
goto release;
|
|
inc_mm_counter(mm, file_rss);
|
|
page_add_file_rmap(page);
|
|
}
|
|
|
|
set_pte_at(mm, address, page_table, entry);
|
|
|
|
/* No need to invalidate - it was non-present before */
|
|
update_mmu_cache(vma, address, entry);
|
|
lazy_mmu_prot_update(entry);
|
|
unlock:
|
|
pte_unmap_unlock(page_table, ptl);
|
|
return VM_FAULT_MINOR;
|
|
release:
|
|
page_cache_release(page);
|
|
goto unlock;
|
|
oom:
|
|
return VM_FAULT_OOM;
|
|
}
|
|
|
|
/*
|
|
* do_no_page() tries to create a new page mapping. It aggressively
|
|
* tries to share with existing pages, but makes a separate copy if
|
|
* the "write_access" parameter is true in order to avoid the next
|
|
* page fault.
|
|
*
|
|
* As this is called only for pages that do not currently exist, we
|
|
* do not need to flush old virtual caches or the TLB.
|
|
*
|
|
* We enter with non-exclusive mmap_sem (to exclude vma changes,
|
|
* but allow concurrent faults), and pte mapped but not yet locked.
|
|
* We return with mmap_sem still held, but pte unmapped and unlocked.
|
|
*/
|
|
static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *page_table, pmd_t *pmd,
|
|
int write_access)
|
|
{
|
|
spinlock_t *ptl;
|
|
struct page *new_page;
|
|
struct address_space *mapping = NULL;
|
|
pte_t entry;
|
|
unsigned int sequence = 0;
|
|
int ret = VM_FAULT_MINOR;
|
|
int anon = 0;
|
|
|
|
pte_unmap(page_table);
|
|
|
|
if (vma->vm_file) {
|
|
mapping = vma->vm_file->f_mapping;
|
|
sequence = mapping->truncate_count;
|
|
smp_rmb(); /* serializes i_size against truncate_count */
|
|
}
|
|
retry:
|
|
new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
|
|
/*
|
|
* No smp_rmb is needed here as long as there's a full
|
|
* spin_lock/unlock sequence inside the ->nopage callback
|
|
* (for the pagecache lookup) that acts as an implicit
|
|
* smp_mb() and prevents the i_size read to happen
|
|
* after the next truncate_count read.
|
|
*/
|
|
|
|
/* no page was available -- either SIGBUS or OOM */
|
|
if (new_page == NOPAGE_SIGBUS)
|
|
return VM_FAULT_SIGBUS;
|
|
if (new_page == NOPAGE_OOM)
|
|
return VM_FAULT_OOM;
|
|
|
|
/*
|
|
* Should we do an early C-O-W break?
|
|
*/
|
|
if (write_access && !(vma->vm_flags & VM_SHARED)) {
|
|
struct page *page;
|
|
|
|
if (unlikely(anon_vma_prepare(vma)))
|
|
goto oom;
|
|
page = alloc_page_vma(GFP_HIGHUSER, vma, address);
|
|
if (!page)
|
|
goto oom;
|
|
copy_user_highpage(page, new_page, address);
|
|
page_cache_release(new_page);
|
|
new_page = page;
|
|
anon = 1;
|
|
}
|
|
|
|
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
|
|
/*
|
|
* For a file-backed vma, someone could have truncated or otherwise
|
|
* invalidated this page. If unmap_mapping_range got called,
|
|
* retry getting the page.
|
|
*/
|
|
if (mapping && unlikely(sequence != mapping->truncate_count)) {
|
|
pte_unmap_unlock(page_table, ptl);
|
|
page_cache_release(new_page);
|
|
cond_resched();
|
|
sequence = mapping->truncate_count;
|
|
smp_rmb();
|
|
goto retry;
|
|
}
|
|
|
|
/*
|
|
* This silly early PAGE_DIRTY setting removes a race
|
|
* due to the bad i386 page protection. But it's valid
|
|
* for other architectures too.
|
|
*
|
|
* Note that if write_access is true, we either now have
|
|
* an exclusive copy of the page, or this is a shared mapping,
|
|
* so we can make it writable and dirty to avoid having to
|
|
* handle that later.
|
|
*/
|
|
/* Only go through if we didn't race with anybody else... */
|
|
if (pte_none(*page_table)) {
|
|
flush_icache_page(vma, new_page);
|
|
entry = mk_pte(new_page, vma->vm_page_prot);
|
|
if (write_access)
|
|
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
|
|
set_pte_at(mm, address, page_table, entry);
|
|
if (anon) {
|
|
inc_mm_counter(mm, anon_rss);
|
|
lru_cache_add_active(new_page);
|
|
page_add_anon_rmap(new_page, vma, address);
|
|
} else if (!(vma->vm_flags & VM_RESERVED)) {
|
|
inc_mm_counter(mm, file_rss);
|
|
page_add_file_rmap(new_page);
|
|
}
|
|
} else {
|
|
/* One of our sibling threads was faster, back out. */
|
|
page_cache_release(new_page);
|
|
goto unlock;
|
|
}
|
|
|
|
/* no need to invalidate: a not-present page shouldn't be cached */
|
|
update_mmu_cache(vma, address, entry);
|
|
lazy_mmu_prot_update(entry);
|
|
unlock:
|
|
pte_unmap_unlock(page_table, ptl);
|
|
return ret;
|
|
oom:
|
|
page_cache_release(new_page);
|
|
return VM_FAULT_OOM;
|
|
}
|
|
|
|
/*
|
|
* Fault of a previously existing named mapping. Repopulate the pte
|
|
* from the encoded file_pte if possible. This enables swappable
|
|
* nonlinear vmas.
|
|
*
|
|
* We enter with non-exclusive mmap_sem (to exclude vma changes,
|
|
* but allow concurrent faults), and pte mapped but not yet locked.
|
|
* We return with mmap_sem still held, but pte unmapped and unlocked.
|
|
*/
|
|
static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *page_table, pmd_t *pmd,
|
|
int write_access, pte_t orig_pte)
|
|
{
|
|
pgoff_t pgoff;
|
|
int err;
|
|
|
|
if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
|
|
return VM_FAULT_MINOR;
|
|
|
|
if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
|
|
/*
|
|
* Page table corrupted: show pte and kill process.
|
|
*/
|
|
print_bad_pte(vma, orig_pte, address);
|
|
return VM_FAULT_OOM;
|
|
}
|
|
/* We can then assume vm->vm_ops && vma->vm_ops->populate */
|
|
|
|
pgoff = pte_to_pgoff(orig_pte);
|
|
err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE,
|
|
vma->vm_page_prot, pgoff, 0);
|
|
if (err == -ENOMEM)
|
|
return VM_FAULT_OOM;
|
|
if (err)
|
|
return VM_FAULT_SIGBUS;
|
|
return VM_FAULT_MAJOR;
|
|
}
|
|
|
|
/*
|
|
* These routines also need to handle stuff like marking pages dirty
|
|
* and/or accessed for architectures that don't do it in hardware (most
|
|
* RISC architectures). The early dirtying is also good on the i386.
|
|
*
|
|
* There is also a hook called "update_mmu_cache()" that architectures
|
|
* with external mmu caches can use to update those (ie the Sparc or
|
|
* PowerPC hashed page tables that act as extended TLBs).
|
|
*
|
|
* We enter with non-exclusive mmap_sem (to exclude vma changes,
|
|
* but allow concurrent faults), and pte mapped but not yet locked.
|
|
* We return with mmap_sem still held, but pte unmapped and unlocked.
|
|
*/
|
|
static inline int handle_pte_fault(struct mm_struct *mm,
|
|
struct vm_area_struct *vma, unsigned long address,
|
|
pte_t *pte, pmd_t *pmd, int write_access)
|
|
{
|
|
pte_t entry;
|
|
pte_t old_entry;
|
|
spinlock_t *ptl;
|
|
|
|
old_entry = entry = *pte;
|
|
if (!pte_present(entry)) {
|
|
if (pte_none(entry)) {
|
|
if (!vma->vm_ops || !vma->vm_ops->nopage)
|
|
return do_anonymous_page(mm, vma, address,
|
|
pte, pmd, write_access);
|
|
return do_no_page(mm, vma, address,
|
|
pte, pmd, write_access);
|
|
}
|
|
if (pte_file(entry))
|
|
return do_file_page(mm, vma, address,
|
|
pte, pmd, write_access, entry);
|
|
return do_swap_page(mm, vma, address,
|
|
pte, pmd, write_access, entry);
|
|
}
|
|
|
|
ptl = pte_lockptr(mm, pmd);
|
|
spin_lock(ptl);
|
|
if (unlikely(!pte_same(*pte, entry)))
|
|
goto unlock;
|
|
if (write_access) {
|
|
if (!pte_write(entry))
|
|
return do_wp_page(mm, vma, address,
|
|
pte, pmd, ptl, entry);
|
|
entry = pte_mkdirty(entry);
|
|
}
|
|
entry = pte_mkyoung(entry);
|
|
if (!pte_same(old_entry, entry)) {
|
|
ptep_set_access_flags(vma, address, pte, entry, write_access);
|
|
update_mmu_cache(vma, address, entry);
|
|
lazy_mmu_prot_update(entry);
|
|
} else {
|
|
/*
|
|
* This is needed only for protection faults but the arch code
|
|
* is not yet telling us if this is a protection fault or not.
|
|
* This still avoids useless tlb flushes for .text page faults
|
|
* with threads.
|
|
*/
|
|
if (write_access)
|
|
flush_tlb_page(vma, address);
|
|
}
|
|
unlock:
|
|
pte_unmap_unlock(pte, ptl);
|
|
return VM_FAULT_MINOR;
|
|
}
|
|
|
|
/*
|
|
* By the time we get here, we already hold the mm semaphore
|
|
*/
|
|
int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
unsigned long address, int write_access)
|
|
{
|
|
pgd_t *pgd;
|
|
pud_t *pud;
|
|
pmd_t *pmd;
|
|
pte_t *pte;
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
inc_page_state(pgfault);
|
|
|
|
if (unlikely(is_vm_hugetlb_page(vma)))
|
|
return hugetlb_fault(mm, vma, address, write_access);
|
|
|
|
pgd = pgd_offset(mm, address);
|
|
pud = pud_alloc(mm, pgd, address);
|
|
if (!pud)
|
|
return VM_FAULT_OOM;
|
|
pmd = pmd_alloc(mm, pud, address);
|
|
if (!pmd)
|
|
return VM_FAULT_OOM;
|
|
pte = pte_alloc_map(mm, pmd, address);
|
|
if (!pte)
|
|
return VM_FAULT_OOM;
|
|
|
|
return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
|
|
}
|
|
|
|
#ifndef __PAGETABLE_PUD_FOLDED
|
|
/*
|
|
* Allocate page upper directory.
|
|
* We've already handled the fast-path in-line.
|
|
*/
|
|
int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
|
|
{
|
|
pud_t *new = pud_alloc_one(mm, address);
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
spin_lock(&mm->page_table_lock);
|
|
if (pgd_present(*pgd)) /* Another has populated it */
|
|
pud_free(new);
|
|
else
|
|
pgd_populate(mm, pgd, new);
|
|
spin_unlock(&mm->page_table_lock);
|
|
return 0;
|
|
}
|
|
#endif /* __PAGETABLE_PUD_FOLDED */
|
|
|
|
#ifndef __PAGETABLE_PMD_FOLDED
|
|
/*
|
|
* Allocate page middle directory.
|
|
* We've already handled the fast-path in-line.
|
|
*/
|
|
int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
|
|
{
|
|
pmd_t *new = pmd_alloc_one(mm, address);
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
spin_lock(&mm->page_table_lock);
|
|
#ifndef __ARCH_HAS_4LEVEL_HACK
|
|
if (pud_present(*pud)) /* Another has populated it */
|
|
pmd_free(new);
|
|
else
|
|
pud_populate(mm, pud, new);
|
|
#else
|
|
if (pgd_present(*pud)) /* Another has populated it */
|
|
pmd_free(new);
|
|
else
|
|
pgd_populate(mm, pud, new);
|
|
#endif /* __ARCH_HAS_4LEVEL_HACK */
|
|
spin_unlock(&mm->page_table_lock);
|
|
return 0;
|
|
}
|
|
#endif /* __PAGETABLE_PMD_FOLDED */
|
|
|
|
int make_pages_present(unsigned long addr, unsigned long end)
|
|
{
|
|
int ret, len, write;
|
|
struct vm_area_struct * vma;
|
|
|
|
vma = find_vma(current->mm, addr);
|
|
if (!vma)
|
|
return -1;
|
|
write = (vma->vm_flags & VM_WRITE) != 0;
|
|
if (addr >= end)
|
|
BUG();
|
|
if (end > vma->vm_end)
|
|
BUG();
|
|
len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
|
|
ret = get_user_pages(current, current->mm, addr,
|
|
len, write, 0, NULL, NULL);
|
|
if (ret < 0)
|
|
return ret;
|
|
return ret == len ? 0 : -1;
|
|
}
|
|
|
|
/*
|
|
* Map a vmalloc()-space virtual address to the physical page.
|
|
*/
|
|
struct page * vmalloc_to_page(void * vmalloc_addr)
|
|
{
|
|
unsigned long addr = (unsigned long) vmalloc_addr;
|
|
struct page *page = NULL;
|
|
pgd_t *pgd = pgd_offset_k(addr);
|
|
pud_t *pud;
|
|
pmd_t *pmd;
|
|
pte_t *ptep, pte;
|
|
|
|
if (!pgd_none(*pgd)) {
|
|
pud = pud_offset(pgd, addr);
|
|
if (!pud_none(*pud)) {
|
|
pmd = pmd_offset(pud, addr);
|
|
if (!pmd_none(*pmd)) {
|
|
ptep = pte_offset_map(pmd, addr);
|
|
pte = *ptep;
|
|
if (pte_present(pte))
|
|
page = pte_page(pte);
|
|
pte_unmap(ptep);
|
|
}
|
|
}
|
|
}
|
|
return page;
|
|
}
|
|
|
|
EXPORT_SYMBOL(vmalloc_to_page);
|
|
|
|
/*
|
|
* Map a vmalloc()-space virtual address to the physical page frame number.
|
|
*/
|
|
unsigned long vmalloc_to_pfn(void * vmalloc_addr)
|
|
{
|
|
return page_to_pfn(vmalloc_to_page(vmalloc_addr));
|
|
}
|
|
|
|
EXPORT_SYMBOL(vmalloc_to_pfn);
|
|
|
|
#if !defined(__HAVE_ARCH_GATE_AREA)
|
|
|
|
#if defined(AT_SYSINFO_EHDR)
|
|
static struct vm_area_struct gate_vma;
|
|
|
|
static int __init gate_vma_init(void)
|
|
{
|
|
gate_vma.vm_mm = NULL;
|
|
gate_vma.vm_start = FIXADDR_USER_START;
|
|
gate_vma.vm_end = FIXADDR_USER_END;
|
|
gate_vma.vm_page_prot = PAGE_READONLY;
|
|
gate_vma.vm_flags = VM_RESERVED;
|
|
return 0;
|
|
}
|
|
__initcall(gate_vma_init);
|
|
#endif
|
|
|
|
struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
|
|
{
|
|
#ifdef AT_SYSINFO_EHDR
|
|
return &gate_vma;
|
|
#else
|
|
return NULL;
|
|
#endif
|
|
}
|
|
|
|
int in_gate_area_no_task(unsigned long addr)
|
|
{
|
|
#ifdef AT_SYSINFO_EHDR
|
|
if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
|
|
return 1;
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
#endif /* __HAVE_ARCH_GATE_AREA */
|