mirror of https://gitee.com/openkylin/linux.git
powerpc/mm/books3s: Add new pte bit to mark pte temporarily invalid.
When splitting a huge pmd pte, we need to mark the pmd entry invalid. We
can do that by clearing _PAGE_PRESENT bit. But then that will be taken as a
swap pte. In order to differentiate between the two use a software pte bit
when invalidating.
For regular pte, due to bd5050e38a
("powerpc/mm/radix: Change pte relax
sequence to handle nest MMU hang") we need to mark the pte entry invalid when
relaxing access permission. Instead of marking pte_none which can result in
different page table walk routines possibly skipping this pte entry, invalidate
it but still keep it marked present.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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@ -44,6 +44,16 @@
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#define _PAGE_PTE 0x4000000000000000UL /* distinguishes PTEs from pointers */
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#define _PAGE_PRESENT 0x8000000000000000UL /* pte contains a translation */
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/*
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* We need to mark a pmd pte invalid while splitting. We can do that by clearing
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* the _PAGE_PRESENT bit. But then that will be taken as a swap pte. In order to
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* differentiate between two use a SW field when invalidating.
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*
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* We do that temporary invalidate for regular pte entry in ptep_set_access_flags
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*
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* This is used only when _PAGE_PRESENT is cleared.
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*/
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#define _PAGE_INVALID _RPAGE_SW0
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/*
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* Top and bottom bits of RPN which can be used by hash
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@ -568,7 +578,13 @@ static inline pte_t pte_clear_savedwrite(pte_t pte)
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static inline int pte_present(pte_t pte)
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{
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return !!(pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT));
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/*
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* A pte is considerent present if _PAGE_PRESENT is set.
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* We also need to consider the pte present which is marked
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* invalid during ptep_set_access_flags. Hence we look for _PAGE_INVALID
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* if we find _PAGE_PRESENT cleared.
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*/
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return !!(pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_INVALID));
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}
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#ifdef CONFIG_PPC_MEM_KEYS
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