diff options
author | Jan Glauber <jang@linux.vnet.ibm.com> | 2011-03-15 17:08:22 +0100 |
---|---|---|
committer | Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> | 2011-03-15 17:08:23 +0100 |
commit | 305b1523250faf9675919def94906775992ce52d (patch) | |
tree | 2dcbe253cf463eca3c0dfcc9ee8ac7b97cfa5021 /arch/s390/mm/pageattr.c | |
parent | d54cddb620fa493968111f479029dcd910fcb921 (diff) | |
download | op-kernel-dev-305b1523250faf9675919def94906775992ce52d.zip op-kernel-dev-305b1523250faf9675919def94906775992ce52d.tar.gz |
[S390] Write protect module text and RO data
Implement write protection for kernel modules text and read-only
data sections by implementing set_memory_[ro|rw] on s390.
Since s390 has no execute bit in the pte's NX is not supported.
set_memory_[ro|rw] will only work on normal pages and not on
large pages, so in case a large page should be modified bail
out with a warning.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm/pageattr.c')
-rw-r--r-- | arch/s390/mm/pageattr.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c new file mode 100644 index 0000000..122ffbd --- /dev/null +++ b/arch/s390/mm/pageattr.c @@ -0,0 +1,55 @@ +/* + * 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/pgtable.h> + +static void change_page_attr(unsigned long addr, int numpages, + pte_t (*set) (pte_t)) +{ + pte_t *ptep, pte; + pmd_t *pmdp; + pud_t *pudp; + pgd_t *pgdp; + int i; + + for (i = 0; i < numpages; i++) { + pgdp = pgd_offset(&init_mm, addr); + pudp = pud_offset(pgdp, addr); + pmdp = pmd_offset(pudp, addr); + if (pmd_huge(*pmdp)) { + WARN_ON_ONCE(1); + continue; + } + ptep = pte_offset_kernel(pmdp, addr + i * PAGE_SIZE); + + pte = *ptep; + pte = set(pte); + ptep_invalidate(&init_mm, addr + i * PAGE_SIZE, ptep); + *ptep = pte; + } +} + +int set_memory_ro(unsigned long addr, int numpages) +{ + change_page_attr(addr, numpages, pte_wrprotect); + return 0; +} +EXPORT_SYMBOL_GPL(set_memory_ro); + +int set_memory_rw(unsigned long addr, int numpages) +{ + change_page_attr(addr, numpages, pte_mkwrite); + return 0; +} +EXPORT_SYMBOL_GPL(set_memory_rw); + +/* not possible */ +int set_memory_nx(unsigned long addr, int numpages) +{ + return 0; +} +EXPORT_SYMBOL_GPL(set_memory_nx); |