forked from Minki/linux
050eef364a
The tlb flushing code uses the mm_users field of the mm_struct to decide if each page table entry needs to be flushed individually with IPTE or if a global flush for the mm_struct is sufficient after all page table updates have been done. The comment for mm_users says "How many users with user space?" but the /proc code increases mm_users after it found the process structure by pid without creating a new user process. Which makes mm_users useless for the decision between the two tlb flusing methods. The current code can be confused to not flush tlb entries by a concurrent access to /proc files if e.g. a fork is in progres. The solution for this problem is to make the tlb flushing logic independent from the mm_users field. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
187 lines
4.6 KiB
C
187 lines
4.6 KiB
C
/*
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* IBM System z Huge TLB Page Support for Kernel.
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*
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* Copyright IBM Corp. 2008
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* Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
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*/
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#ifndef _ASM_S390_HUGETLB_H
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#define _ASM_S390_HUGETLB_H
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#define is_hugepage_only_range(mm, addr, len) 0
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#define hugetlb_free_pgd_range free_pgd_range
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void set_huge_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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* If the arch doesn't supply something else, assume that hugepage
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* size aligned regions are ok without further preparation.
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*/
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static inline int prepare_hugepage_range(struct file *file,
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unsigned long addr, unsigned long len)
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{
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if (len & ~HPAGE_MASK)
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return -EINVAL;
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if (addr & ~HPAGE_MASK)
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return -EINVAL;
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return 0;
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}
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#define hugetlb_prefault_arch_hook(mm) do { } while (0)
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int arch_prepare_hugepage(struct page *page);
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void arch_release_hugepage(struct page *page);
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static inline pte_t pte_mkhuge(pte_t pte)
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{
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/*
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* PROT_NONE needs to be remapped from the pte type to the ste type.
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* The HW invalid bit is also different for pte and ste. The pte
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* invalid bit happens to be the same as the ste _SEGMENT_ENTRY_LARGE
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* bit, so we don't have to clear it.
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*/
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if (pte_val(pte) & _PAGE_INVALID) {
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if (pte_val(pte) & _PAGE_SWT)
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pte_val(pte) |= _HPAGE_TYPE_NONE;
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pte_val(pte) |= _SEGMENT_ENTRY_INV;
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}
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/*
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* Clear SW pte bits SWT and SWX, there are no SW bits in a segment
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* table entry.
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*/
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pte_val(pte) &= ~(_PAGE_SWT | _PAGE_SWX);
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/*
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* Also set the change-override bit because we don't need dirty bit
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* tracking for hugetlbfs pages.
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*/
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pte_val(pte) |= (_SEGMENT_ENTRY_LARGE | _SEGMENT_ENTRY_CO);
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return pte;
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}
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static inline pte_t huge_pte_wrprotect(pte_t pte)
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{
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pte_val(pte) |= _PAGE_RO;
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return pte;
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}
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static inline int huge_pte_none(pte_t pte)
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{
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return (pte_val(pte) & _SEGMENT_ENTRY_INV) &&
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!(pte_val(pte) & _SEGMENT_ENTRY_RO);
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}
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static inline pte_t huge_ptep_get(pte_t *ptep)
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{
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pte_t pte = *ptep;
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unsigned long mask;
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if (!MACHINE_HAS_HPAGE) {
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ptep = (pte_t *) (pte_val(pte) & _SEGMENT_ENTRY_ORIGIN);
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if (ptep) {
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mask = pte_val(pte) &
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(_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO);
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pte = pte_mkhuge(*ptep);
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pte_val(pte) |= mask;
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}
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}
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return pte;
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}
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static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
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unsigned long addr, pte_t *ptep)
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{
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pte_t pte = huge_ptep_get(ptep);
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mm->context.flush_mm = 1;
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pmd_clear((pmd_t *) ptep);
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return pte;
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}
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static inline void __pmd_csp(pmd_t *pmdp)
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{
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register unsigned long reg2 asm("2") = pmd_val(*pmdp);
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register unsigned long reg3 asm("3") = pmd_val(*pmdp) |
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_SEGMENT_ENTRY_INV;
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register unsigned long reg4 asm("4") = ((unsigned long) pmdp) + 5;
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asm volatile(
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" csp %1,%3"
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: "=m" (*pmdp)
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: "d" (reg2), "d" (reg3), "d" (reg4), "m" (*pmdp) : "cc");
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pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
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}
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static inline void __pmd_idte(unsigned long address, pmd_t *pmdp)
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{
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unsigned long sto = (unsigned long) pmdp -
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pmd_index(address) * sizeof(pmd_t);
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if (!(pmd_val(*pmdp) & _SEGMENT_ENTRY_INV)) {
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asm volatile(
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" .insn rrf,0xb98e0000,%2,%3,0,0"
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: "=m" (*pmdp)
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: "m" (*pmdp), "a" (sto),
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"a" ((address & HPAGE_MASK))
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);
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}
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pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
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}
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static inline void huge_ptep_invalidate(struct mm_struct *mm,
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unsigned long address, pte_t *ptep)
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{
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pmd_t *pmdp = (pmd_t *) ptep;
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if (!MACHINE_HAS_IDTE) {
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__pmd_csp(pmdp);
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if (mm->context.noexec) {
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pmdp = get_shadow_table(pmdp);
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__pmd_csp(pmdp);
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}
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return;
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}
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__pmd_idte(address, pmdp);
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if (mm->context.noexec) {
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pmdp = get_shadow_table(pmdp);
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__pmd_idte(address, pmdp);
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}
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return;
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}
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#define huge_ptep_set_access_flags(__vma, __addr, __ptep, __entry, __dirty) \
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({ \
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int __changed = !pte_same(huge_ptep_get(__ptep), __entry); \
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if (__changed) { \
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huge_ptep_invalidate((__vma)->vm_mm, __addr, __ptep); \
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set_huge_pte_at((__vma)->vm_mm, __addr, __ptep, __entry); \
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} \
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__changed; \
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})
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#define huge_ptep_set_wrprotect(__mm, __addr, __ptep) \
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({ \
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pte_t __pte = huge_ptep_get(__ptep); \
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if (pte_write(__pte)) { \
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(__mm)->context.flush_mm = 1; \
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if (atomic_read(&(__mm)->context.attach_count) > 1 || \
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(__mm) != current->active_mm) \
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huge_ptep_invalidate(__mm, __addr, __ptep); \
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set_huge_pte_at(__mm, __addr, __ptep, \
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huge_pte_wrprotect(__pte)); \
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} \
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})
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static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
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unsigned long address, pte_t *ptep)
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{
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huge_ptep_invalidate(vma->vm_mm, address, ptep);
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}
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#endif /* _ASM_S390_HUGETLB_H */
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