x86: cpa, check if we changed anything and tlb flushing is necessary
Flush tlbs only when there was a real change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -21,6 +21,7 @@ struct cpa_data {
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int numpages;
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int numpages;
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pgprot_t mask_set;
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pgprot_t mask_set;
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pgprot_t mask_clr;
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pgprot_t mask_clr;
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int flushtlb;
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};
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};
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static inline int
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static inline int
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@ -329,11 +330,19 @@ static int __change_page_attr(unsigned long address, struct cpa_data *cpa)
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* not the memory it points to
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* not the memory it points to
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*/
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*/
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new_pte = pfn_pte(pte_pfn(old_pte), canon_pgprot(new_prot));
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new_pte = pfn_pte(pte_pfn(old_pte), canon_pgprot(new_prot));
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set_pte_atomic(kpte, new_pte);
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/*
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* Do we really change anything ?
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*/
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if (pte_val(old_pte) != pte_val(new_pte)) {
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set_pte_atomic(kpte, new_pte);
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cpa->flushtlb = 1;
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}
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} else {
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} else {
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err = split_large_page(kpte, address);
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err = split_large_page(kpte, address);
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if (!err)
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if (!err)
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goto repeat;
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goto repeat;
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cpa->flushtlb = 1;
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}
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}
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return err;
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return err;
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}
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}
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@ -438,9 +447,16 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages,
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cpa.numpages = numpages;
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cpa.numpages = numpages;
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cpa.mask_set = mask_set;
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cpa.mask_set = mask_set;
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cpa.mask_clr = mask_clr;
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cpa.mask_clr = mask_clr;
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cpa.flushtlb = 0;
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ret = __change_page_attr_set_clr(&cpa);
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ret = __change_page_attr_set_clr(&cpa);
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/*
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* Check whether we really changed something:
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*/
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if (!cpa.flushtlb)
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return ret;
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/*
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/*
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* No need to flush, when we did not set any of the caching
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* No need to flush, when we did not set any of the caching
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* attributes:
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* attributes:
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