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authorChristian Borntraeger <borntraeger@de.ibm.com>2010-04-09 13:43:01 +0200
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2010-04-09 13:43:02 +0200
commit6af7eea2aee57b869f34eba0a94ef122fe90fbfd (patch)
treeb434f6300b9e1ba588230472ecf3e6c0024292e9 /arch/s390/mm
parent176b1803ce4690d0dd94e16f118dbd14af045034 (diff)
downloadlinux-linaro-android-6af7eea2aee57b869f34eba0a94ef122fe90fbfd.tar.gz
[S390] s390: disable change bit override
commit 6a985c6194017de2c062916ad1cd00dee0302c40 ([S390] s390: use change recording override for kernel mapping) deactivated the change bit recording for the kernel mapping to improve the performance. This works most of the time, but there are cases (e.g. kernel runs in home space, futex atomic compare xcmg) where we modify user memory with the kernel mapping instead of the user mapping. Instead of fixing these cases, this patch just deactivates change bit override to avoid future problems with other kernel code that might use the kernel mapping for user memory. CC: stable@kernel.org Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/vmem.c11
1 files changed, 3 insertions, 8 deletions
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 8ea3144b45b..90165e7ca04 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -71,12 +71,8 @@ static pte_t __ref *vmem_pte_alloc(void)
pte = alloc_bootmem(PTRS_PER_PTE * sizeof(pte_t));
if (!pte)
return NULL;
- if (MACHINE_HAS_HPAGE)
- clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY | _PAGE_CO,
- PTRS_PER_PTE * sizeof(pte_t));
- else
- clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY,
- PTRS_PER_PTE * sizeof(pte_t));
+ clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY,
+ PTRS_PER_PTE * sizeof(pte_t));
return pte;
}
@@ -117,8 +113,7 @@ static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
if (MACHINE_HAS_HPAGE && !(address & ~HPAGE_MASK) &&
(address + HPAGE_SIZE <= start + size) &&
(address >= HPAGE_SIZE)) {
- pte_val(pte) |= _SEGMENT_ENTRY_LARGE |
- _SEGMENT_ENTRY_CO;
+ pte_val(pte) |= _SEGMENT_ENTRY_LARGE;
pmd_val(*pm_dir) = pte_val(pte);
address += HPAGE_SIZE - PAGE_SIZE;
continue;