void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
{
unsigned long last_addr;
void __iomem *p = __ioremap(phys_addr, size, _PAGE_PCD);
if (!p)
return p;
/* Guaranteed to be > phys_addr, as per __ioremap() */
last_addr = phys_addr + size - 1;
if (last_addr < virt_to_phys(high_memory)) {
struct page *ppage = virt_to_page(__va(phys_addr));
unsigned long npages;
phys_addr &= PAGE_MASK;
/* This might overflow and become zero.. */
last_addr = PAGE_ALIGN(last_addr);
/* .. but that's ok, because modulo-2**n arithmetic will make
* the page-aligned "last - first" come out right.
*/
npages = (last_addr - phys_addr) >> PAGE_SHIFT;
if (change_page_attr(ppage, npages, PAGE_KERNEL_NOCACHE) < 0) {
iounmap(p);
p = NULL;
}
global_flush_tlb();
}
return p;
}
static inline void set_addr_ro(unsigned long addr, bool flag) {
#if (defined(CONFIG_XEN) || defined(CONFIG_X86_PAE)) && LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
struct page *pg;
pgprot_t prot;
pg = virt_to_page(addr);
prot.pgprot = VM_READ;
change_page_attr(pg, 1, prot);
#else
unsigned int level;
pte_t *pte;
// only set back to readonly if it was readonly before
if (flag) {
pte = tpe_lookup_address(addr, &level);
#if !defined(CONFIG_X86_64) && LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
pte_val(*pte) = pte_val(*pte) &~_PAGE_RW;
#else
pte->pte = pte->pte &~_PAGE_RW;
#endif
}
#endif
}
static inline void set_addr_rw(unsigned long addr, bool *flag) {
#if (defined(CONFIG_XEN) || defined(CONFIG_X86_PAE)) && LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
struct page *pg;
pgprot_t prot;
pg = virt_to_page(addr);
prot.pgprot = VM_READ | VM_WRITE;
change_page_attr(pg, 1, prot);
#else
unsigned int level;
pte_t *pte;
*flag = true;
pte = tpe_lookup_address(addr, &level);
#if !defined(CONFIG_X86_64) && LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
if (pte_val(*pte) & _PAGE_RW) *flag = false;
else pte_val(*pte) |= _PAGE_RW;
#else
if (pte->pte & _PAGE_RW) *flag = false;
else pte->pte |= _PAGE_RW;
#endif
#endif
}
void set_addr_ro(unsigned long addr, bool flag) {
struct page *pg;
pgprot_t prot;
pg = virt_to_page(addr);
prot.pgprot = VM_READ;
change_page_attr(pg, 1, prot);
}
void kernel_map_pages(struct page *page, int numpages, int enable)
{
if (PageHighMem(page))
return;
/* the return value is ignored - the calls cannot fail,
* large pages are disabled at boot time.
*/
change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
/* we should perform an IPI and flush all tlbs,
* but that can deadlock->flush only current cpu.
*/
__flush_tlb_all();
}
void mark_rodata_ro(void)
{
unsigned long addr = (unsigned long)__start_rodata;
for (; addr < (unsigned long)__end_rodata; addr += PAGE_SIZE)
change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RO);
printk("Write protecting the kernel read-only data: %uk\n",
(__end_rodata - __start_rodata) >> 10);
/*
* change_page_attr() requires a global_flush_tlb() call after it.
* We do this after the printk so that if something went wrong in the
* change, the printk gets out at least to give a better debug hint
* of who is the culprit.
*/
global_flush_tlb();
}
int set_memory_rw(unsigned long addr, int numpages)
{
change_page_attr(addr, numpages, pte_mkwrite);
return 0;
}
int set_memory_ro(unsigned long addr, int numpages)
{
change_page_attr(addr, numpages, pte_wrprotect);
return 0;
}
