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 | |
| parent | d54cddb620fa493968111f479029dcd910fcb921 (diff) | |
[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')
| -rw-r--r-- | arch/s390/Kconfig.debug | 3 | ||||
| -rw-r--r-- | arch/s390/include/asm/cacheflush.h | 4 | ||||
| -rw-r--r-- | arch/s390/mm/Makefile | 1 | ||||
| -rw-r--r-- | arch/s390/mm/pageattr.c | 55 |
4 files changed, 63 insertions, 0 deletions
diff --git a/arch/s390/Kconfig.debug b/arch/s390/Kconfig.debug index 2b380df95606..d76cef3fef37 100644 --- a/arch/s390/Kconfig.debug +++ b/arch/s390/Kconfig.debug @@ -31,4 +31,7 @@ config DEBUG_STRICT_USER_COPY_CHECKS If unsure, or if you run an older (pre 4.4) gcc, say N. +config DEBUG_SET_MODULE_RONX + def_bool y + depends on MODULES endmenu diff --git a/arch/s390/include/asm/cacheflush.h b/arch/s390/include/asm/cacheflush.h index 7e1f77620624..43a5c78046db 100644 --- a/arch/s390/include/asm/cacheflush.h +++ b/arch/s390/include/asm/cacheflush.h @@ -8,4 +8,8 @@ void kernel_map_pages(struct page *page, int numpages, int enable); #endif +int set_memory_ro(unsigned long addr, int numpages); +int set_memory_rw(unsigned long addr, int numpages); +int set_memory_nx(unsigned long addr, int numpages); + #endif /* _S390_CACHEFLUSH_H */ diff --git a/arch/s390/mm/Makefile b/arch/s390/mm/Makefile index 6fbc6f3fbdf2..d98fe9004a52 100644 --- a/arch/s390/mm/Makefile +++ b/arch/s390/mm/Makefile @@ -6,3 +6,4 @@ obj-y := init.o fault.o extmem.o mmap.o vmem.o pgtable.o maccess.o \ page-states.o gup.o obj-$(CONFIG_CMM) += cmm.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o +obj-$(CONFIG_DEBUG_SET_MODULE_RONX) += pageattr.o diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c new file mode 100644 index 000000000000..122ffbd08ce0 --- /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); |