path: root/arch/parisc/kernel/entry.S
diff options
authorJames Bottomley <James.Bottomley@HansenPartnership.com>2011-04-14 18:25:21 -0500
committerJames Bottomley <James.Bottomley@suse.de>2011-04-15 12:55:18 -0500
commitd7dd2ff11b7fcd425aca5a875983c862d19a67ae (patch)
tree6ad74d89d2355861b513eefb763ea6103a8d68e7 /arch/parisc/kernel/entry.S
parente38f5b745075828ac51b12c8c95c85a7be4a3ec7 (diff)
[PARISC] only make executable areas executable
Currently parisc has the whole kernel marked as RWX, meaning any kernel page at all is eligible to be executed. This can cause a theoretical problem on systems with combined I/D TLB because the act of referencing a page causes a TLB insertion with an executable bit. This TLB entry may be used by the CPU as the basis for speculating the page into the I-Cache. If this speculated page is subsequently used for a user process, there is the possibility we will get a stale I-cache line picked up as the binary executes. As a point of good practise, only mark actual kernel text pages as executable. The same has to be done for init_text pages, but they're converted to data pages (and the I-Cache flushed) when the init memory is released. Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'arch/parisc/kernel/entry.S')
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index ead8d2a1034..6f059443914 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -692,6 +692,9 @@ ENTRY(fault_vector_11)
+ /* Fault vector is separately protected and *must* be on its own page */
+ .align PAGE_SIZE
.import handle_interruption,code
.import do_cpu_irq_mask,code