101f12af16
Registering a callback handler through register_die_notifier() is obviously
primarily intended for use by modules. However, the way these currently
get called it is basically impossible for them to actually be used by
modules, as there is, on non-PAE configurationes, a good chance (the larger
the module, the better) for the system to crash as a result.
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.
Besides the modular aspect, similar problems would even arise for in-
kernel consumers of the API if they touched ioremap()ed or vmalloc()ed
memory inside their handlers.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
158 lines
4.2 KiB
C
158 lines
4.2 KiB
C
#ifndef _I386_PGTABLE_3LEVEL_H
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#define _I386_PGTABLE_3LEVEL_H
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#include <asm-generic/pgtable-nopud.h>
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/*
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* Intel Physical Address Extension (PAE) Mode - three-level page
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* tables on PPro+ CPUs.
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*
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* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
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*/
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#define pte_ERROR(e) \
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printk("%s:%d: bad pte %p(%08lx%08lx).\n", __FILE__, __LINE__, &(e), (e).pte_high, (e).pte_low)
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#define pmd_ERROR(e) \
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printk("%s:%d: bad pmd %p(%016Lx).\n", __FILE__, __LINE__, &(e), pmd_val(e))
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#define pgd_ERROR(e) \
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printk("%s:%d: bad pgd %p(%016Lx).\n", __FILE__, __LINE__, &(e), pgd_val(e))
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#define pud_none(pud) 0
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#define pud_bad(pud) 0
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#define pud_present(pud) 1
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/*
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* Is the pte executable?
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*/
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static inline int pte_x(pte_t pte)
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{
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return !(pte_val(pte) & _PAGE_NX);
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}
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/*
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* All present user-pages with !NX bit are user-executable:
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*/
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static inline int pte_exec(pte_t pte)
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{
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return pte_user(pte) && pte_x(pte);
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}
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/*
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* All present pages with !NX bit are kernel-executable:
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*/
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static inline int pte_exec_kernel(pte_t pte)
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{
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return pte_x(pte);
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}
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/* Rules for using set_pte: the pte being assigned *must* be
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* either not present or in a state where the hardware will
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* not attempt to update the pte. In places where this is
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* not possible, use pte_get_and_clear to obtain the old pte
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* value and then use set_pte to update it. -ben
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*/
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static inline void set_pte(pte_t *ptep, pte_t pte)
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{
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ptep->pte_high = pte.pte_high;
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smp_wmb();
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ptep->pte_low = pte.pte_low;
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}
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#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
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#define __HAVE_ARCH_SET_PTE_ATOMIC
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#define set_pte_atomic(pteptr,pteval) \
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set_64bit((unsigned long long *)(pteptr),pte_val(pteval))
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#define set_pmd(pmdptr,pmdval) \
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set_64bit((unsigned long long *)(pmdptr),pmd_val(pmdval))
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#define set_pud(pudptr,pudval) \
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(*(pudptr) = (pudval))
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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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* We do not let the generic code free and clear pgd entries due to
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* this erratum.
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*/
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static inline void pud_clear (pud_t * pud) { }
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#define pud_page(pud) \
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((struct page *) __va(pud_val(pud) & PAGE_MASK))
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#define pud_page_kernel(pud) \
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((unsigned long) __va(pud_val(pud) & PAGE_MASK))
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/* Find an entry in the second-level page table.. */
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#define pmd_offset(pud, address) ((pmd_t *) pud_page(*(pud)) + \
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pmd_index(address))
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static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
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{
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pte_t res;
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/* xchg acts as a barrier before the setting of the high bits */
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res.pte_low = xchg(&ptep->pte_low, 0);
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res.pte_high = ptep->pte_high;
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ptep->pte_high = 0;
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return res;
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}
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static inline int pte_same(pte_t a, pte_t b)
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{
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return a.pte_low == b.pte_low && a.pte_high == b.pte_high;
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}
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#define pte_page(x) pfn_to_page(pte_pfn(x))
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static inline int pte_none(pte_t pte)
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{
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return !pte.pte_low && !pte.pte_high;
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}
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static inline unsigned long pte_pfn(pte_t pte)
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{
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return (pte.pte_low >> PAGE_SHIFT) |
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(pte.pte_high << (32 - PAGE_SHIFT));
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}
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extern unsigned long long __supported_pte_mask;
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static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
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{
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pte_t pte;
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pte.pte_high = (page_nr >> (32 - PAGE_SHIFT)) | \
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(pgprot_val(pgprot) >> 32);
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pte.pte_high &= (__supported_pte_mask >> 32);
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pte.pte_low = ((page_nr << PAGE_SHIFT) | pgprot_val(pgprot)) & \
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__supported_pte_mask;
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return pte;
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}
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static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot)
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{
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return __pmd((((unsigned long long)page_nr << PAGE_SHIFT) | \
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pgprot_val(pgprot)) & __supported_pte_mask);
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}
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/*
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* Bits 0, 6 and 7 are taken in the low part of the pte,
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* put the 32 bits of offset into the high part.
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*/
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#define pte_to_pgoff(pte) ((pte).pte_high)
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#define pgoff_to_pte(off) ((pte_t) { _PAGE_FILE, (off) })
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#define PTE_FILE_MAX_BITS 32
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/* Encode and de-code a swap entry */
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#define __swp_type(x) (((x).val) & 0x1f)
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#define __swp_offset(x) ((x).val >> 5)
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#define __swp_entry(type, offset) ((swp_entry_t){(type) | (offset) << 5})
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#define __pte_to_swp_entry(pte) ((swp_entry_t){ (pte).pte_high })
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#define __swp_entry_to_pte(x) ((pte_t){ 0, (x).val })
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#define __pmd_free_tlb(tlb, x) do { } while (0)
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#define vmalloc_sync_all() ((void)0)
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#endif /* _I386_PGTABLE_3LEVEL_H */
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