[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>
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index 6e81bb5..cedbbb8 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -61,8 +61,10 @@
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/bug.h>
+#include <linux/mm.h>
#include <linux/slab.h>
+#include <asm/pgtable.h>
#include <asm/unwind.h>
#if 0
@@ -214,7 +216,13 @@
{
if (size == 0)
return NULL;
- return vmalloc(size);
+ /* using RWX means less protection for modules, but it's
+ * easier than trying to map the text, data, init_text and
+ * init_data correctly */
+ return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
+ GFP_KERNEL | __GFP_HIGHMEM,
+ PAGE_KERNEL_RWX, -1,
+ __builtin_return_address(0));
}
#ifndef CONFIG_64BIT