fa28ba21ce
PAE mode requires that we reload cr3 in order to guarantee that changes to the pgd will be noticed by the processor. This means that in principle pud_clear needs to reload cr3 every time. However, because reloading cr3 implies a tlb flush, we want to avoid it where possible. pud_clear() is only used in a couple of places: - in free_pmd_range(), when pulling down a range of process address space, and - huge_pmd_unshare() In both cases, the calling code will do a a tlb flush anyway, so there's no need to do it within pud_clear(). In free_pmd_range(), the pud_clear is immediately followed by pmd_free_tlb(); we can hook that to make the mmu_gather do an unconditional full flush to make sure cr3 gets reloaded. In huge_pmd_unshare, it is followed by flush_tlb_range, which always results in a full cr3-reload tlb flush. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: William Irwin <wli@holomorphy.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
106 lines
2.8 KiB
C
106 lines
2.8 KiB
C
#ifndef _I386_PGALLOC_H
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#define _I386_PGALLOC_H
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#include <linux/threads.h>
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#include <linux/mm.h> /* for struct page */
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#include <asm/tlb.h>
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#include <asm-generic/tlb.h>
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#ifdef CONFIG_PARAVIRT
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#include <asm/paravirt.h>
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#else
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#define paravirt_alloc_pt(mm, pfn) do { } while (0)
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#define paravirt_alloc_pd(mm, pfn) do { } while (0)
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#define paravirt_alloc_pd_clone(pfn, clonepfn, start, count) do { } while (0)
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#define paravirt_release_pt(pfn) do { } while (0)
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#define paravirt_release_pd(pfn) do { } while (0)
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#endif
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static inline void pmd_populate_kernel(struct mm_struct *mm,
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pmd_t *pmd, pte_t *pte)
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{
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paravirt_alloc_pt(mm, __pa(pte) >> PAGE_SHIFT);
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set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
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}
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static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, struct page *pte)
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{
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unsigned long pfn = page_to_pfn(pte);
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paravirt_alloc_pt(mm, pfn);
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set_pmd(pmd, __pmd(((pteval_t)pfn << PAGE_SHIFT) | _PAGE_TABLE));
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}
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/*
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* Allocate and free page tables.
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*/
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extern pgd_t *pgd_alloc(struct mm_struct *);
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extern void pgd_free(pgd_t *pgd);
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extern pte_t *pte_alloc_one_kernel(struct mm_struct *, unsigned long);
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extern struct page *pte_alloc_one(struct mm_struct *, unsigned long);
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static inline void pte_free_kernel(pte_t *pte)
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{
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free_page((unsigned long)pte);
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}
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static inline void pte_free(struct page *pte)
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{
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__free_page(pte);
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}
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static inline void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
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{
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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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/*
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* In the PAE case we free the pmds as part of the pgd.
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*/
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static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
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{
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return (pmd_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
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}
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static inline void pmd_free(pmd_t *pmd)
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{
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BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
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free_page((unsigned long)pmd);
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}
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static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
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{
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/* This is called just after the pmd has been detached from
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the pgd, which requires a full tlb flush to be recognized
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by the CPU. Rather than incurring multiple tlb flushes
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while the address space is being pulled down, make the tlb
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gathering machinery do a full flush when we're done. */
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tlb->fullmm = 1;
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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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static inline void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
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{
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paravirt_alloc_pd(mm, __pa(pmd) >> PAGE_SHIFT);
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/* Note: almost everything apart from _PAGE_PRESENT is
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reserved at the pmd (PDPT) level. */
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set_pud(pudp, __pud(__pa(pmd) | _PAGE_PRESENT));
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/*
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* Pentium-II erratum A13: in PAE mode we explicitly have to flush
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* the TLB via cr3 if the top-level pgd is changed...
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*/
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if (mm == current->active_mm)
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write_cr3(read_cr3());
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}
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#endif /* CONFIG_X86_PAE */
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#endif /* _I386_PGALLOC_H */
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