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kernel/linux-imx6_3.14.28/arch/s390/mm/pageattr.c 2.9 KB
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  /*
   * Copyright IBM Corp. 2011
   * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
   */
  #include <linux/hugetlb.h>
  #include <linux/module.h>
  #include <linux/mm.h>
  #include <asm/cacheflush.h>
  #include <asm/pgtable.h>
  #include <asm/page.h>
  
  #if PAGE_DEFAULT_KEY
  static inline unsigned long sske_frame(unsigned long addr, unsigned char skey)
  {
  	asm volatile(".insn rrf,0xb22b0000,%[skey],%[addr],9,0"
  		     : [addr] "+a" (addr) : [skey] "d" (skey));
  	return addr;
  }
  
  void __storage_key_init_range(unsigned long start, unsigned long end)
  {
  	unsigned long boundary, size;
  
  	while (start < end) {
  		if (MACHINE_HAS_EDAT1) {
  			/* set storage keys for a 1MB frame */
  			size = 1UL << 20;
  			boundary = (start + size) & ~(size - 1);
  			if (boundary <= end) {
  				do {
  					start = sske_frame(start, PAGE_DEFAULT_KEY);
  				} while (start < boundary);
  				continue;
  			}
  		}
  		page_set_storage_key(start, PAGE_DEFAULT_KEY, 0);
  		start += PAGE_SIZE;
  	}
  }
  #endif
  
  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) || pud_large(*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;
  }
  
  #ifdef CONFIG_DEBUG_PAGEALLOC
  void kernel_map_pages(struct page *page, int numpages, int enable)
  {
  	unsigned long address;
  	pgd_t *pgd;
  	pud_t *pud;
  	pmd_t *pmd;
  	pte_t *pte;
  	int i;
  
  	for (i = 0; i < numpages; i++) {
  		address = page_to_phys(page + i);
  		pgd = pgd_offset_k(address);
  		pud = pud_offset(pgd, address);
  		pmd = pmd_offset(pud, address);
  		pte = pte_offset_kernel(pmd, address);
  		if (!enable) {
  			__ptep_ipte(address, pte);
  			pte_val(*pte) = _PAGE_INVALID;
  			continue;
  		}
  		pte_val(*pte) = __pa(address);
  	}
  }
  
  #ifdef CONFIG_HIBERNATION
  bool kernel_page_present(struct page *page)
  {
  	unsigned long addr;
  	int cc;
  
  	addr = page_to_phys(page);
  	asm volatile(
  		"	lra	%1,0(%1)
  "
  		"	ipm	%0
  "
  		"	srl	%0,28"
  		: "=d" (cc), "+a" (addr) : : "cc");
  	return cc == 0;
  }
  #endif /* CONFIG_HIBERNATION */
  
  #endif /* CONFIG_DEBUG_PAGEALLOC */