[patch 2/7] x86, cpa: remove USER permission from the very early identity mapping attribute

From: Suresh Siddha
Date: Tue Sep 23 2008 - 17:21:57 EST


remove USER from the PTE/PDE attributes for the very early identity
mapping. We overwrite these mappings with KERNEL attribute later
in the boot. Just being paranoid here as there is no need for USER bit
to be set.

If this breaks something(don't know the history), then we can simply drop
this change.

Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
---

Index: tip/include/asm-x86/pgtable.h
===================================================================
--- tip.orig/include/asm-x86/pgtable.h 2008-09-22 15:59:32.000000000 -0700
+++ tip/include/asm-x86/pgtable.h 2008-09-22 15:59:34.000000000 -0700
@@ -148,8 +148,8 @@
#ifdef CONFIG_X86_64
#define __PAGE_KERNEL_IDENT_LARGE_EXEC __PAGE_KERNEL_LARGE_EXEC
#else
-#define PTE_IDENT_ATTR 0x007 /* PRESENT+RW+USER */
-#define PDE_IDENT_ATTR 0x067 /* PRESENT+RW+USER+DIRTY+ACCESSED */
+#define PTE_IDENT_ATTR 0x003 /* PRESENT+RW */
+#define PDE_IDENT_ATTR 0x063 /* PRESENT+RW+DIRTY+ACCESSED */
#define PGD_IDENT_ATTR 0x001 /* PRESENT (no other attributes) */
#endif


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