diff mbox series

[v8,8/9] mm: Clear arch specific VM flags on protection change

Message ID 9297528d3184e695e98129f4362a8f399b5783cf.1506089472.git.khalid.aziz@oracle.com
State Changes Requested
Delegated to: David Miller
Headers show
Series Application Data Integrity feature introduced by SPARC M7 | expand

Commit Message

Khalid Aziz Sept. 25, 2017, 4:48 p.m. UTC 
When protection bits are changed on a VMA, some of the architecture
specific flags should be cleared as well. An examples of this are the
PKEY flags on x86. This patch expands the current code that clears
PKEY flags for x86, to support similar functionality for other
architectures as well.

Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Khalid Aziz <khalid@gonehiking.org>
---
v7:
	- new patch

 include/linux/mm.h | 6 ++++++
 mm/mprotect.c      | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index c1f6c95f3496..cbb21facce6b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -271,6 +271,12 @@  extern unsigned int kobjsize(const void *objp);
 /* This mask is used to clear all the VMA flags used by mlock */
 #define VM_LOCKED_CLEAR_MASK	(~(VM_LOCKED | VM_LOCKONFAULT))
 
+/* Arch-specific flags to clear when updating VM flags on protection change */
+#ifndef VM_ARCH_CLEAR
+# define VM_ARCH_CLEAR	VM_NONE
+#endif
+#define VM_FLAGS_CLEAR	(ARCH_VM_PKEY_FLAGS | VM_ARCH_CLEAR)
+
 /*
  * mapping from the currently active vm_flags protection bits (the
  * low four bits) to a page protection mask..
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 4f0e46bb1797..85b65b3a823d 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -453,7 +453,7 @@  static int do_mprotect_pkey(unsigned long start, size_t len,
 		 * cleared from the VMA.
 		 */
 		mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC |
-					ARCH_VM_PKEY_FLAGS;
+					VM_FLAGS_CLEAR;
 
 		new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey);
 		newflags = calc_vm_prot_bits(prot, new_vma_pkey);