390 lines
9.5 KiB
C
390 lines
9.5 KiB
C
/*
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* linux/arch/i386/mm/pgtable.c
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*/
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/nmi.h>
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#include <linux/swap.h>
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#include <linux/smp.h>
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#include <linux/highmem.h>
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#include <linux/slab.h>
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#include <linux/pagemap.h>
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#include <linux/spinlock.h>
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#include <linux/module.h>
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#include <linux/quicklist.h>
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#include <asm/system.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/fixmap.h>
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#include <asm/e820.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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void show_mem(void)
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{
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int total = 0, reserved = 0;
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int shared = 0, cached = 0;
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int highmem = 0;
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struct page *page;
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pg_data_t *pgdat;
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unsigned long i;
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unsigned long flags;
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printk(KERN_INFO "Mem-info:\n");
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show_free_areas();
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for_each_online_pgdat(pgdat) {
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pgdat_resize_lock(pgdat, &flags);
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for (i = 0; i < pgdat->node_spanned_pages; ++i) {
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if (unlikely(i % MAX_ORDER_NR_PAGES == 0))
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touch_nmi_watchdog();
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page = pgdat_page_nr(pgdat, i);
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total++;
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if (PageHighMem(page))
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highmem++;
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if (PageReserved(page))
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reserved++;
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else if (PageSwapCache(page))
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cached++;
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else if (page_count(page))
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shared += page_count(page) - 1;
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}
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pgdat_resize_unlock(pgdat, &flags);
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}
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printk(KERN_INFO "%d pages of RAM\n", total);
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printk(KERN_INFO "%d pages of HIGHMEM\n", highmem);
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printk(KERN_INFO "%d reserved pages\n", reserved);
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printk(KERN_INFO "%d pages shared\n", shared);
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printk(KERN_INFO "%d pages swap cached\n", cached);
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printk(KERN_INFO "%lu pages dirty\n", global_page_state(NR_FILE_DIRTY));
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printk(KERN_INFO "%lu pages writeback\n",
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global_page_state(NR_WRITEBACK));
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printk(KERN_INFO "%lu pages mapped\n", global_page_state(NR_FILE_MAPPED));
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printk(KERN_INFO "%lu pages slab\n",
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global_page_state(NR_SLAB_RECLAIMABLE) +
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global_page_state(NR_SLAB_UNRECLAIMABLE));
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printk(KERN_INFO "%lu pages pagetables\n",
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global_page_state(NR_PAGETABLE));
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}
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/*
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* Associate a virtual page frame with a given physical page frame
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* and protection flags for that frame.
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*/
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static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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pgd = swapper_pg_dir + pgd_index(vaddr);
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if (pgd_none(*pgd)) {
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BUG();
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return;
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}
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pud = pud_offset(pgd, vaddr);
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if (pud_none(*pud)) {
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BUG();
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return;
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}
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pmd = pmd_offset(pud, vaddr);
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if (pmd_none(*pmd)) {
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BUG();
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return;
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}
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pte = pte_offset_kernel(pmd, vaddr);
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if (pgprot_val(flags))
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set_pte_present(&init_mm, vaddr, pte, pfn_pte(pfn, flags));
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else
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pte_clear(&init_mm, vaddr, pte);
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/*
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* It's enough to flush this one mapping.
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* (PGE mappings get flushed as well)
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*/
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__flush_tlb_one(vaddr);
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}
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/*
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* Associate a large virtual page frame with a given physical page frame
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* and protection flags for that frame. pfn is for the base of the page,
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* vaddr is what the page gets mapped to - both must be properly aligned.
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* The pmd must already be instantiated. Assumes PAE mode.
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*/
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void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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if (vaddr & (PMD_SIZE-1)) { /* vaddr is misaligned */
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printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
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return; /* BUG(); */
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}
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if (pfn & (PTRS_PER_PTE-1)) { /* pfn is misaligned */
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printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
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return; /* BUG(); */
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}
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pgd = swapper_pg_dir + pgd_index(vaddr);
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if (pgd_none(*pgd)) {
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printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
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return; /* BUG(); */
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}
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pud = pud_offset(pgd, vaddr);
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pmd = pmd_offset(pud, vaddr);
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set_pmd(pmd, pfn_pmd(pfn, flags));
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/*
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* It's enough to flush this one mapping.
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* (PGE mappings get flushed as well)
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*/
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__flush_tlb_one(vaddr);
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}
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static int fixmaps;
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unsigned long __FIXADDR_TOP = 0xfffff000;
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EXPORT_SYMBOL(__FIXADDR_TOP);
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void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
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{
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unsigned long address = __fix_to_virt(idx);
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if (idx >= __end_of_fixed_addresses) {
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BUG();
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return;
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}
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set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
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fixmaps++;
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}
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/**
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* reserve_top_address - reserves a hole in the top of kernel address space
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* @reserve - size of hole to reserve
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*
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* Can be used to relocate the fixmap area and poke a hole in the top
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* of kernel address space to make room for a hypervisor.
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*/
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void reserve_top_address(unsigned long reserve)
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{
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BUG_ON(fixmaps > 0);
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printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
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(int)-reserve);
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__FIXADDR_TOP = -reserve - PAGE_SIZE;
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__VMALLOC_RESERVE += reserve;
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}
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pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
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{
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return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
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}
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pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
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{
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struct page *pte;
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#ifdef CONFIG_HIGHPTE
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pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT|__GFP_ZERO, 0);
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#else
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pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
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#endif
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if (pte)
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pgtable_page_ctor(pte);
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return pte;
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}
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/*
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* List of all pgd's needed for non-PAE so it can invalidate entries
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* in both cached and uncached pgd's; not needed for PAE since the
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* kernel pmd is shared. If PAE were not to share the pmd a similar
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* tactic would be needed. This is essentially codepath-based locking
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* against pageattr.c; it is the unique case in which a valid change
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* of kernel pagetables can't be lazily synchronized by vmalloc faults.
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* vmalloc faults work because attached pagetables are never freed.
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* -- wli
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*/
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static inline void pgd_list_add(pgd_t *pgd)
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{
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struct page *page = virt_to_page(pgd);
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list_add(&page->lru, &pgd_list);
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}
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static inline void pgd_list_del(pgd_t *pgd)
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{
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struct page *page = virt_to_page(pgd);
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list_del(&page->lru);
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}
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#define UNSHARED_PTRS_PER_PGD \
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(SHARED_KERNEL_PMD ? USER_PTRS_PER_PGD : PTRS_PER_PGD)
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static void pgd_ctor(void *p)
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{
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pgd_t *pgd = p;
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unsigned long flags;
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/* Clear usermode parts of PGD */
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memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
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spin_lock_irqsave(&pgd_lock, flags);
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/* If the pgd points to a shared pagetable level (either the
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ptes in non-PAE, or shared PMD in PAE), then just copy the
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references from swapper_pg_dir. */
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if (PAGETABLE_LEVELS == 2 ||
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(PAGETABLE_LEVELS == 3 && SHARED_KERNEL_PMD)) {
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clone_pgd_range(pgd + USER_PTRS_PER_PGD,
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swapper_pg_dir + USER_PTRS_PER_PGD,
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KERNEL_PGD_PTRS);
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paravirt_alloc_pd_clone(__pa(pgd) >> PAGE_SHIFT,
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__pa(swapper_pg_dir) >> PAGE_SHIFT,
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USER_PTRS_PER_PGD,
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KERNEL_PGD_PTRS);
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}
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/* list required to sync kernel mapping updates */
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if (!SHARED_KERNEL_PMD)
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pgd_list_add(pgd);
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spin_unlock_irqrestore(&pgd_lock, flags);
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}
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static void pgd_dtor(void *pgd)
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{
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unsigned long flags; /* can be called from interrupt context */
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if (SHARED_KERNEL_PMD)
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return;
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spin_lock_irqsave(&pgd_lock, flags);
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pgd_list_del(pgd);
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spin_unlock_irqrestore(&pgd_lock, flags);
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}
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#ifdef CONFIG_X86_PAE
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/*
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* Mop up any pmd pages which may still be attached to the pgd.
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* Normally they will be freed by munmap/exit_mmap, but any pmd we
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* preallocate which never got a corresponding vma will need to be
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* freed manually.
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*/
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static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
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{
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int i;
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for(i = 0; i < UNSHARED_PTRS_PER_PGD; i++) {
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pgd_t pgd = pgdp[i];
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if (pgd_val(pgd) != 0) {
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pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
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pgdp[i] = native_make_pgd(0);
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paravirt_release_pd(pgd_val(pgd) >> PAGE_SHIFT);
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pmd_free(mm, pmd);
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}
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}
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}
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/*
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* In PAE mode, we need to do a cr3 reload (=tlb flush) when
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* updating the top-level pagetable entries to guarantee the
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* processor notices the update. Since this is expensive, and
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* all 4 top-level entries are used almost immediately in a
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* new process's life, we just pre-populate them here.
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*
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* Also, if we're in a paravirt environment where the kernel pmd is
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* not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate
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* and initialize the kernel pmds here.
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*/
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static int pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd)
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{
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pud_t *pud;
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unsigned long addr;
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int i;
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pud = pud_offset(pgd, 0);
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for (addr = i = 0; i < UNSHARED_PTRS_PER_PGD;
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i++, pud++, addr += PUD_SIZE) {
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pmd_t *pmd = pmd_alloc_one(mm, addr);
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if (!pmd) {
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pgd_mop_up_pmds(mm, pgd);
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return 0;
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}
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if (i >= USER_PTRS_PER_PGD)
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memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]),
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sizeof(pmd_t) * PTRS_PER_PMD);
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pud_populate(mm, pud, pmd);
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}
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return 1;
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}
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#else /* !CONFIG_X86_PAE */
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/* No need to prepopulate any pagetable entries in non-PAE modes. */
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static int pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd)
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{
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return 1;
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}
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static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
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{
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}
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#endif /* CONFIG_X86_PAE */
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pgd_t *pgd_alloc(struct mm_struct *mm)
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{
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pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
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/* so that alloc_pd can use it */
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mm->pgd = pgd;
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if (pgd)
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pgd_ctor(pgd);
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if (pgd && !pgd_prepopulate_pmd(mm, pgd)) {
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pgd_dtor(pgd);
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free_page((unsigned long)pgd);
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pgd = NULL;
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}
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return pgd;
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}
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void pgd_free(struct mm_struct *mm, pgd_t *pgd)
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{
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pgd_mop_up_pmds(mm, pgd);
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pgd_dtor(pgd);
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free_page((unsigned long)pgd);
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}
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void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
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{
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pgtable_page_dtor(pte);
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paravirt_release_pt(page_to_pfn(pte));
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tlb_remove_page(tlb, pte);
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}
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#ifdef CONFIG_X86_PAE
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void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
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{
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paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
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tlb_remove_page(tlb, virt_to_page(pmd));
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}
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#endif
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int pmd_bad(pmd_t pmd)
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{
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WARN_ON_ONCE(pmd_bad_v1(pmd) != pmd_bad_v2(pmd));
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return pmd_bad_v1(pmd);
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}
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