diff options
Diffstat (limited to 'arch/i386/mm')
| -rw-r--r-- | arch/i386/mm/init.c | 24 | ||||
| -rw-r--r-- | arch/i386/mm/pageattr.c | 27 |
2 files changed, 45 insertions, 6 deletions
diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c index 06e26f00623..7df494b51a5 100644 --- a/arch/i386/mm/init.c +++ b/arch/i386/mm/init.c @@ -735,6 +735,30 @@ void free_initmem(void) printk (KERN_INFO "Freeing unused kernel memory: %dk freed\n", (__init_end - __init_begin) >> 10); } +#ifdef CONFIG_DEBUG_RODATA + +extern char __start_rodata, __end_rodata; +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: %luk\n", + (unsigned long)(&__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(); +} +#endif + + #ifdef CONFIG_BLK_DEV_INITRD void free_initrd_mem(unsigned long start, unsigned long end) { diff --git a/arch/i386/mm/pageattr.c b/arch/i386/mm/pageattr.c index f600fc244f0..c30a16df644 100644 --- a/arch/i386/mm/pageattr.c +++ b/arch/i386/mm/pageattr.c @@ -13,6 +13,7 @@ #include <asm/processor.h> #include <asm/tlbflush.h> #include <asm/pgalloc.h> +#include <asm/sections.h> static DEFINE_SPINLOCK(cpa_lock); static struct list_head df_list = LIST_HEAD_INIT(df_list); @@ -36,7 +37,8 @@ pte_t *lookup_address(unsigned long address) return pte_offset_kernel(pmd, address); } -static struct page *split_large_page(unsigned long address, pgprot_t prot) +static struct page *split_large_page(unsigned long address, pgprot_t prot, + pgprot_t ref_prot) { int i; unsigned long addr; @@ -54,7 +56,7 @@ static struct page *split_large_page(unsigned long address, pgprot_t prot) pbase = (pte_t *)page_address(base); for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) { set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT, - addr == address ? prot : PAGE_KERNEL)); + addr == address ? prot : ref_prot)); } return base; } @@ -98,11 +100,18 @@ static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte) */ static inline void revert_page(struct page *kpte_page, unsigned long address) { - pte_t *linear = (pte_t *) + pgprot_t ref_prot; + pte_t *linear; + + ref_prot = + ((address & LARGE_PAGE_MASK) < (unsigned long)&_etext) + ? PAGE_KERNEL_LARGE_EXEC : PAGE_KERNEL_LARGE; + + linear = (pte_t *) pmd_offset(pud_offset(pgd_offset_k(address), address), address); set_pmd_pte(linear, address, pfn_pte((__pa(address) & LARGE_PAGE_MASK) >> PAGE_SHIFT, - PAGE_KERNEL_LARGE)); + ref_prot)); } static int @@ -123,10 +132,16 @@ __change_page_attr(struct page *page, pgprot_t prot) if ((pte_val(*kpte) & _PAGE_PSE) == 0) { set_pte_atomic(kpte, mk_pte(page, prot)); } else { - struct page *split = split_large_page(address, prot); + pgprot_t ref_prot; + struct page *split; + + ref_prot = + ((address & LARGE_PAGE_MASK) < (unsigned long)&_etext) + ? PAGE_KERNEL_EXEC : PAGE_KERNEL; + split = split_large_page(address, prot, ref_prot); if (!split) return -ENOMEM; - set_pmd_pte(kpte,address,mk_pte(split, PAGE_KERNEL)); + set_pmd_pte(kpte,address,mk_pte(split, ref_prot)); kpte_page = split; } get_page(kpte_page); |