From: Joerg Roedel <[email protected]> Mapping the kernel text area to user-space makes only sense if it has the same permissions as in the kernel page-table. If permissions are different this will cause a TLB reload when using the kernel page-table, which is as good as not mapping it at all.
On 64-bit kernels this patch makes no difference, as the whole range cloned by pti_clone_kernel_text() is mapped RO anyway. On 32 bit there are writeable mappings in the range, so just keep the permissions as they are. Signed-off-by: Joerg Roedel <[email protected]> --- arch/x86/mm/pti.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index 9cceae3..e3059bb0 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -460,7 +460,7 @@ void pti_clone_kernel_text(void) if (!pti_kernel_image_global_ok()) return; - pti_clone_pmds(start, end, _PAGE_RW); + pti_clone_pmds(start, end, 0); } /* -- 2.7.4
