5311ab62cd
Normally when running in PAE mode, the 4th PMD maps the kernel address space, which can be shared among all processes (since they all need the same kernel mappings). Xen, however, does not allow guests to have the kernel pmd shared between page tables, so parameterize pgtable.c to allow both modes of operation. There are several side-effects of this. One is that vmalloc will update the kernel address space mappings, and those updates need to be propagated into all processes if the kernel mappings are not intrinsically shared. In the non-PAE case, this is done by maintaining a pgd_list of all processes; this list is used when all process pagetables must be updated. pgd_list is threaded via otherwise unused entries in the page structure for the pgd, which means that the pgd must be page-sized for this to work. Normally the PAE pgd is only 4x64 byte entries large, but Xen requires the PAE pgd to page aligned anyway, so this patch forces the pgd to be page aligned+sized when the kernel pmd is unshared, to accomodate both these requirements. Also, since there may be several distinct kernel pmds (if the user/kernel split is below 3G), there's no point in allocating them from a slab cache; they're just allocated with get_free_page and initialized appropriately. (Of course the could be cached if there is just a single kernel pmd - which is the default with a 3G user/kernel split - but it doesn't seem worthwhile to add yet another case into this code). [ Many thanks to wli for review comments. ] Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Zachary Amsden <zach@vmware.com> Cc: Christoph Lameter <clameter@sgi.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
203 lines
5.5 KiB
C
203 lines
5.5 KiB
C
#ifndef _I386_PGTABLE_3LEVEL_H
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#define _I386_PGTABLE_3LEVEL_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 native_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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static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep , pte_t pte)
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{
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native_set_pte(ptep, pte);
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}
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/*
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* Since this is only called on user PTEs, and the page fault handler
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* must handle the already racy situation of simultaneous page faults,
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* we are justified in merely clearing the PTE present bit, followed
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* by a set. The ordering here is important.
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*/
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static inline void native_set_pte_present(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep, pte_t pte)
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{
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ptep->pte_low = 0;
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smp_wmb();
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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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static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
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{
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set_64bit((unsigned long long *)(ptep),native_pte_val(pte));
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}
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static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
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{
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set_64bit((unsigned long long *)(pmdp),native_pmd_val(pmd));
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}
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static inline void native_set_pud(pud_t *pudp, pud_t pud)
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{
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*pudp = pud;
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}
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/*
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* For PTEs and PDEs, we must clear the P-bit first when clearing a page table
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* entry, so clear the bottom half first and enforce ordering with a compiler
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* barrier.
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*/
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static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
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{
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ptep->pte_low = 0;
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smp_wmb();
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ptep->pte_high = 0;
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}
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static inline void native_pmd_clear(pmd_t *pmd)
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{
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u32 *tmp = (u32 *)pmd;
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*tmp = 0;
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smp_wmb();
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*(tmp + 1) = 0;
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}
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#ifndef CONFIG_PARAVIRT
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#define set_pte(ptep, pte) native_set_pte(ptep, pte)
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#define set_pte_at(mm, addr, ptep, pte) native_set_pte_at(mm, addr, ptep, pte)
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#define set_pte_present(mm, addr, ptep, pte) native_set_pte_present(mm, addr, ptep, pte)
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#define set_pte_atomic(ptep, pte) native_set_pte_atomic(ptep, pte)
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#define set_pmd(pmdp, pmd) native_set_pmd(pmdp, pmd)
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#define set_pud(pudp, pud) native_set_pud(pudp, pud)
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#define pte_clear(mm, addr, ptep) native_pte_clear(mm, addr, ptep)
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#define pmd_clear(pmd) native_pmd_clear(pmd)
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#endif
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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_vaddr(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 native_ptep_get_and_clear(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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#define __HAVE_ARCH_PTE_SAME
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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_val(pte) >> 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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return __pte((((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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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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#endif /* _I386_PGTABLE_3LEVEL_H */
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