The x86 family of processors do not directly create read-only and Dirty
PTEs.  These PTEs are created by software.  One such case is that kernel
read-only pages are historically setup as Dirty.

New processors that support Shadow Stack regard read-only and Dirty PTEs as
shadow stack pages.  This results in ambiguity between shadow stack and
kernel read-only pages.  To resolve this, removed Dirty from kernel read-
only pages.

Signed-off-by: Yu-cheng Yu <yu-cheng...@intel.com>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: Kees Cook <keesc...@chromium.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Peter Zijlstra <pet...@infradead.org>
---
 arch/x86/include/asm/pgtable_types.h | 6 +++---
 arch/x86/mm/pat/set_memory.c         | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_types.h 
b/arch/x86/include/asm/pgtable_types.h
index f24d7ef8fffa..9db61817dfff 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -192,10 +192,10 @@ enum page_cache_mode {
 #define _KERNPG_TABLE           (__PP|__RW|   0|___A|   0|___D|   0|   0| _ENC)
 #define _PAGE_TABLE_NOENC       (__PP|__RW|_USR|___A|   0|___D|   0|   0)
 #define _PAGE_TABLE             (__PP|__RW|_USR|___A|   0|___D|   0|   0| _ENC)
-#define __PAGE_KERNEL_RO        (__PP|   0|   0|___A|__NX|___D|   0|___G)
-#define __PAGE_KERNEL_ROX       (__PP|   0|   0|___A|   0|___D|   0|___G)
+#define __PAGE_KERNEL_RO        (__PP|   0|   0|___A|__NX|   0|   0|___G)
+#define __PAGE_KERNEL_ROX       (__PP|   0|   0|___A|   0|   0|   0|___G)
 #define __PAGE_KERNEL_NOCACHE   (__PP|__RW|   0|___A|__NX|___D|   0|___G| __NC)
-#define __PAGE_KERNEL_VVAR      (__PP|   0|_USR|___A|__NX|___D|   0|___G)
+#define __PAGE_KERNEL_VVAR      (__PP|   0|_USR|___A|__NX|   0|   0|___G)
 #define __PAGE_KERNEL_LARGE     (__PP|__RW|   0|___A|__NX|___D|_PSE|___G)
 #define __PAGE_KERNEL_LARGE_EXEC (__PP|__RW|   0|___A|   0|___D|_PSE|___G)
 #define __PAGE_KERNEL_WP        (__PP|__RW|   0|___A|__NX|___D|   0|___G| __WP)
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 16f878c26667..6bebb95a6988 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -1932,7 +1932,7 @@ int set_memory_nx(unsigned long addr, int numpages)
 
 int set_memory_ro(unsigned long addr, int numpages)
 {
-       return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_RW), 0);
+       return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_RW | 
_PAGE_DIRTY), 0);
 }
 
 int set_memory_rw(unsigned long addr, int numpages)
-- 
2.21.0

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