From: Thomas Gleixner Share the entry text PMD of the kernel mapping with the user space mapping. If large pages are enabled this is a single PMD entry and at the point where it is copied into the user page table the RW bit has not been cleared yet. Clear it right away so the user space visible map becomes RX. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com --- arch/x86/mm/pti.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -256,6 +256,15 @@ static void __init pti_clone_user_shared } /* + * Clone the populated PMDs of the entry and irqentry text and force it RO. + */ +static void __init pti_clone_entry_text(void) +{ + pti_clone_pmds((unsigned long) __entry_text_start, + (unsigned long) __irqentry_text_end, _PAGE_RW); +} + +/* * Initialize kernel page table isolation */ void __init pti_init(void) @@ -266,4 +275,5 @@ void __init pti_init(void) pr_info("enabled\n"); pti_clone_user_shared(); + pti_clone_entry_text(); }