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/*
* Copyright IBM Corp. 2011
* Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <asm/cacheflush.h>
#include <asm/pgtable.h>
static pte_t *walk_page_table(unsigned long addr)
{
pgd_t *pgdp;
pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep;
pgdp = pgd_offset_k(addr);
if (pgd_none(*pgdp))
return NULL;
pudp = pud_offset(pgdp, addr);
if (pud_none(*pudp))
return NULL;
pmdp = pmd_offset(pudp, addr);
if (pmd_none(*pmdp) || pmd_large(*pmdp))
return NULL;
ptep = pte_offset_kernel(pmdp, addr);
if (pte_none(*ptep))
return NULL;
return ptep;
}
static void change_page_attr(unsigned long addr, int numpages,
pte_t (*set) (pte_t))
{
pte_t *ptep, pte;
int i;
for (i = 0; i < numpages; i++) {
ptep = walk_page_table(addr);
if (WARN_ON_ONCE(!ptep))
break;
pte = *ptep;
pte = set(pte);
__ptep_ipte(addr, ptep);
*ptep = pte;
addr += PAGE_SIZE;
}
}
int set_memory_ro(unsigned long addr, int numpages)
{
change_page_attr(addr, numpages, pte_wrprotect);
return 0;
}
int set_memory_rw(unsigned long addr, int numpages)
{
change_page_attr(addr, numpages, pte_mkwrite);
return 0;
}
/* not possible */
int set_memory_nx(unsigned long addr, int numpages)
{
return 0;
}
int set_memory_x(unsigned long addr, int numpages)
{
return 0;
}
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