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 <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Kees Cook <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Peter Zijlstra <[email protected]> --- 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 394757ee030a..b8b79d618bbc 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -194,10 +194,10 @@ 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
