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@@ -0,0 +1,55 @@
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+/*
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+ * Copyright IBM Corp. 2011
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+ * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
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+ */
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+#include <linux/module.h>
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+#include <linux/mm.h>
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+#include <linux/hugetlb.h>
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+#include <asm/pgtable.h>
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+
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+static void change_page_attr(unsigned long addr, int numpages,
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+ pte_t (*set) (pte_t))
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+{
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+ pte_t *ptep, pte;
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+ pmd_t *pmdp;
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+ pud_t *pudp;
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+ pgd_t *pgdp;
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+ int i;
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+
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+ for (i = 0; i < numpages; i++) {
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+ pgdp = pgd_offset(&init_mm, addr);
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+ pudp = pud_offset(pgdp, addr);
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+ pmdp = pmd_offset(pudp, addr);
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+ if (pmd_huge(*pmdp)) {
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+ WARN_ON_ONCE(1);
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+ continue;
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+ }
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+ ptep = pte_offset_kernel(pmdp, addr + i * PAGE_SIZE);
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+
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+ pte = *ptep;
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+ pte = set(pte);
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+ ptep_invalidate(&init_mm, addr + i * PAGE_SIZE, ptep);
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+ *ptep = pte;
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+ }
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+}
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+
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+int set_memory_ro(unsigned long addr, int numpages)
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+{
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+ change_page_attr(addr, numpages, pte_wrprotect);
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+ return 0;
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+}
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+EXPORT_SYMBOL_GPL(set_memory_ro);
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+
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+int set_memory_rw(unsigned long addr, int numpages)
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+{
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+ change_page_attr(addr, numpages, pte_mkwrite);
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+ return 0;
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+}
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+EXPORT_SYMBOL_GPL(set_memory_rw);
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+
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+/* not possible */
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+int set_memory_nx(unsigned long addr, int numpages)
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+{
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+ return 0;
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+}
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+EXPORT_SYMBOL_GPL(set_memory_nx);
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