73 lines
1.3 KiB
C
73 lines
1.3 KiB
C
/*
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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/cacheflush.h>
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#include <asm/pgtable.h>
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static pte_t *walk_page_table(unsigned long addr)
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{
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pgd_t *pgdp;
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pud_t *pudp;
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pmd_t *pmdp;
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pte_t *ptep;
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pgdp = pgd_offset_k(addr);
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if (pgd_none(*pgdp))
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return NULL;
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pudp = pud_offset(pgdp, addr);
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if (pud_none(*pudp))
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return NULL;
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pmdp = pmd_offset(pudp, addr);
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if (pmd_none(*pmdp) || pmd_large(*pmdp))
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return NULL;
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ptep = pte_offset_kernel(pmdp, addr);
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if (pte_none(*ptep))
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return NULL;
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return ptep;
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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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int i;
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for (i = 0; i < numpages; i++) {
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ptep = walk_page_table(addr);
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if (WARN_ON_ONCE(!ptep))
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break;
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pte = *ptep;
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pte = set(pte);
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__ptep_ipte(addr, ptep);
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*ptep = pte;
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addr += PAGE_SIZE;
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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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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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/* 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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int set_memory_x(unsigned long addr, int numpages)
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{
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return 0;
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}
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