Messages in this thread | | | Date | Fri, 24 Feb 2006 14:28:44 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] Enable mprotect on huge pages |
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"Zhang, Yanmin" <yanmin_zhang@linux.intel.com> wrote: > > From: Zhang, Yanmin <yanmin.zhang@intel.com> > > 2.6.16-rc3 uses hugetlb on-demand paging, but it doesn_t support hugetlb > mprotect. My patch against 2.6.16-rc3 enables this capability. >
Well I suppose that makes sense. It does assume that the normal pte protection-changing APIs do the right thing on all architectures which implement huge pages. That's quite possibly the case, but we should confirm that.
> + > +void hugetlb_change_protection(struct vm_area_struct *vma, > + unsigned long address, unsigned long end, pgprot_t newprot) > +{ > + struct mm_struct *mm = vma->vm_mm; > + unsigned long start = address; > + pte_t *ptep; > + pte_t pte; > + > + BUG_ON(address >= end); > + flush_cache_range(vma, address, end); > + > + spin_lock(&mm->page_table_lock); > + for (; address < end; address += HPAGE_SIZE) { > + ptep = huge_pte_offset(mm, address); > + if (!ptep) > + continue; > + if (pte_present(*ptep)) { > + pte = ptep_get_and_clear(mm, address, ptep); > + pte = pte_modify(pte, newprot); > + set_huge_pte_at(mm, addr, ptep, pte); > + lazy_mmu_prot_update(pte); > + } > + } > + spin_unlock(&mm->page_table_lock); > + > + flush_tlb_range(vma, start, end); > +}
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