[PATCH] [31/31] Clean up pte_exec

Andi Kleen
2008-01-14T22:28:17Z

- Rename it to pte_exec() from pte_exec_kernel(). There is nothing
kernel specific in there.
- Move it into the common file because _PAGE_NX is 0 on !PAE and then
pte_exec() will be always evaluate to true.

Signed-off-by: Andi Kleen <ak@suse.de>

---
arch/x86/mm/fault_32.c | 2 +-
include/asm-x86/pgtable-2level.h | 8 --------
include/asm-x86/pgtable-3level.h | 8 --------
include/asm-x86/pgtable.h | 1 +
4 files changed, 2 insertions(+), 17 deletions(-)

Index: linux/include/asm-x86/pgtable-2level.h
===================================================================
--- linux.orig/include/asm-x86/pgtable-2level.h
+++ linux/include/asm-x86/pgtable-2level.h
@@ -56,14 +56,6 @@ static inline pte_t native_ptep_get_and_
#define pte_pfn(x) (pte_val(x) >> PAGE_SHIFT)

/*
- * All present pages are kernel-executable:
- */
-static inline int pte_exec_kernel(pte_t pte)
-{
- return 1;
-}
-
-/*
* Bits 0, 6 and 7 are taken, split up the 29 bits of offset
* into this range:
*/
Index: linux/include/asm-x86/pgtable.h
===================================================================
--- linux.orig/include/asm-x86/pgtable.h
+++ linux/include/asm-x86/pgtable.h
@@ -143,6 +143,7 @@ static inline int pte_write(pte_t pte)
static inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
static inline int pte_huge(pte_t pte) { return pte_val(pte) & _PAGE_PSE; }
static inline int pte_global(pte_t pte) { return pte_val(pte) & _PAGE_GLOBAL; }
+static inline int pte_exec(pte_t pte) { return !(pte_val(pte) & _PAGE_NX); }

static inline int pmd_large(pmd_t pte) {
return (pmd_val(pte) & (_PAGE_PSE|_PAGE_PRESENT)) ==
Index: linux/include/asm-x86/pgtable-3level.h
===================================================================
--- linux.orig/include/asm-x86/pgtable-3level.h
+++ linux/include/asm-x86/pgtable-3level.h
@@ -19,14 +19,6 @@
#define pud_bad(pud) 0
#define pud_present(pud) 1

-/*
- * All present pages with !NX bit are kernel-executable:
- */
-static inline int pte_exec_kernel(pte_t pte)
-{
- return !(pte_val(pte) & _PAGE_NX);
-}
-
/* Rules for using set_pte: the pte being assigned *must* be
* either not present or in a state where the hardware will
* not attempt to update the pte. In places where this is
Index: linux/arch/x86/mm/fault_32.c
===================================================================
--- linux.orig/arch/x86/mm/fault_32.c
+++ linux/arch/x86/mm/fault_32.c
@@ -574,7 +574,7 @@ no_context:
int level;
pte_t *pte = lookup_address(address, &level);

- if (pte && pte_present(*pte) && !pte_exec_kernel(*pte))
+ if (pte && pte_present(*pte) && !pte_exec(*pte))
printk(KERN_CRIT "kernel tried to execute "
"NX-protected page - exploit attempt? "
"(uid: %d)\n", current->uid);