path: root/arch/s390/mm/hugetlbpage.c
diff options
authorMartin Schwidefsky <schwidefsky@de.ibm.com>2011-05-23 10:24:23 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2011-05-23 10:24:28 +0200
commit043d07084b5347a26eab0a07aa13a4a929ad9e71 (patch)
tree13c2a902ccb2ecb779722c8b81ada32d242760c8 /arch/s390/mm/hugetlbpage.c
parent[S390] cio: fix unreg race in set_online path (diff)
[S390] Remove data execution protection
The noexec support on s390 does not rely on a bit in the page table entry but utilizes the secondary space mode to distinguish between memory accesses for instructions vs. data. The noexec code relies on the assumption that the cpu will always use the secondary space page table for data accesses while it is running in the secondary space mode. Up to the z9-109 class machines this has been the case. Unfortunately this is not true anymore with z10 and later machines. The load-relative-long instructions lrl, lgrl and lgfrl access the memory operand using the same addressing-space mode that has been used to fetch the instruction. This breaks the noexec mode for all user space binaries compiled with march=z10 or later. The only option is to remove the current noexec support. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm/hugetlbpage.c')
1 files changed, 0 insertions, 10 deletions
diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
index 639cd21f2218..a4d856db9154 100644
--- a/arch/s390/mm/hugetlbpage.c
+++ b/arch/s390/mm/hugetlbpage.c
@@ -13,7 +13,6 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *pteptr, pte_t pteval)
pmd_t *pmdp = (pmd_t *) pteptr;
- pte_t shadow_pteval = pteval;
unsigned long mask;
@@ -21,18 +20,9 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
mask = pte_val(pteval) &
pte_val(pteval) = (_SEGMENT_ENTRY + __pa(pteptr)) | mask;
- if (mm->context.noexec) {
- pteptr += PTRS_PER_PTE;
- pte_val(shadow_pteval) =
- (_SEGMENT_ENTRY + __pa(pteptr)) | mask;
- }
pmd_val(*pmdp) = pte_val(pteval);
- if (mm->context.noexec) {
- pmdp = get_shadow_table(pmdp);
- pmd_val(*pmdp) = pte_val(shadow_pteval);
- }
int arch_prepare_hugepage(struct page *page)