8c914cb704
While the modular aspect of the respective i386 patch doesn't apply to x86-64 (as the top level page directory entry is shared between modules and the base kernel), handlers registered with register_die_notifier() are still under similar constraints for touching ioremap()ed or vmalloc()ed memory. The likelihood of this problem becoming visible is of course significantly lower, as the assigned virtual addresses would have to cross a 2**39 byte boundary. This is because the callback gets invoked (a) in the page fault path before the top level page table propagation gets carried out (hence a fault to propagate the top level page table entry/entries mapping to module's code/data would nest infinitly) and (b) in the NMI path, where nested faults must absolutely not happen, since otherwise the IRET from the nested fault re-enables NMIs, potentially resulting in nested NMI occurences. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
133 lines
3.3 KiB
C
133 lines
3.3 KiB
C
#ifndef _X86_64_PGALLOC_H
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#define _X86_64_PGALLOC_H
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#include <asm/fixmap.h>
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#include <asm/pda.h>
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#include <linux/threads.h>
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#include <linux/mm.h>
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#define pmd_populate_kernel(mm, pmd, pte) \
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set_pmd(pmd, __pmd(_PAGE_TABLE | __pa(pte)))
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#define pud_populate(mm, pud, pmd) \
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set_pud(pud, __pud(_PAGE_TABLE | __pa(pmd)))
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#define pgd_populate(mm, pgd, pud) \
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set_pgd(pgd, __pgd(_PAGE_TABLE | __pa(pud)))
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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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set_pmd(pmd, __pmd(_PAGE_TABLE | (page_to_pfn(pte) << PAGE_SHIFT)));
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}
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static inline pmd_t *get_pmd(void)
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{
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return (pmd_t *)get_zeroed_page(GFP_KERNEL);
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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 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 pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
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{
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return (pud_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
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}
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static inline void pud_free (pud_t *pud)
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{
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BUG_ON((unsigned long)pud & (PAGE_SIZE-1));
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free_page((unsigned long)pud);
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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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spin_lock(&pgd_lock);
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page->index = (pgoff_t)pgd_list;
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if (pgd_list)
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pgd_list->private = (unsigned long)&page->index;
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pgd_list = page;
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page->private = (unsigned long)&pgd_list;
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spin_unlock(&pgd_lock);
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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 *next, **pprev, *page = virt_to_page(pgd);
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spin_lock(&pgd_lock);
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next = (struct page *)page->index;
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pprev = (struct page **)page->private;
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*pprev = next;
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if (next)
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next->private = (unsigned long)pprev;
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spin_unlock(&pgd_lock);
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}
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static inline pgd_t *pgd_alloc(struct mm_struct *mm)
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{
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unsigned boundary;
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pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
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if (!pgd)
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return NULL;
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pgd_list_add(pgd);
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/*
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* Copy kernel pointers in from init.
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* Could keep a freelist or slab cache of those because the kernel
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* part never changes.
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*/
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boundary = pgd_index(__PAGE_OFFSET);
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memset(pgd, 0, boundary * sizeof(pgd_t));
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memcpy(pgd + boundary,
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init_level4_pgt + boundary,
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(PTRS_PER_PGD - boundary) * sizeof(pgd_t));
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return pgd;
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}
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static inline void pgd_free(pgd_t *pgd)
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{
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BUG_ON((unsigned long)pgd & (PAGE_SIZE-1));
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pgd_list_del(pgd);
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free_page((unsigned long)pgd);
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}
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static inline 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_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
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}
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static inline struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
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{
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void *p = (void *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
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if (!p)
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return NULL;
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return virt_to_page(p);
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}
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/* Should really implement gc for free page table pages. This could be
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done with a reference count in struct page. */
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static inline void pte_free_kernel(pte_t *pte)
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{
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BUG_ON((unsigned long)pte & (PAGE_SIZE-1));
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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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#define __pte_free_tlb(tlb,pte) tlb_remove_page((tlb),(pte))
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#define __pmd_free_tlb(tlb,x) tlb_remove_page((tlb),virt_to_page(x))
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#define __pud_free_tlb(tlb,x) tlb_remove_page((tlb),virt_to_page(x))
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#endif /* _X86_64_PGALLOC_H */
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