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.yu@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
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 816b31c68550..1314bf7606b3 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -193,10 +193,10 @@ 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 40baa90e74f4..f104d3c30bda 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
