From: Andy Lutomirski <l...@kernel.org>
Share the FIX_USR_SHARED PMDs so the user space and kernel space page
tables have the same PMD page.
[ tglx: Made it use the FIX_USR_SHARED range so later additions
are covered automatically ]
Signed-off-by: Andy Lutomirski <l...@kernel.org>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Cc: Boris Ostrovsky <boris.ostrov...@oracle.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Brian Gerst <brge...@gmail.com>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: David Laight <david.lai...@aculab.com>
Cc: Denys Vlasenko <dvlas...@redhat.com>
Cc: Eduardo Valentin <edu...@amazon.com>
Cc: Greg KH <gre...@linuxfoundation.org>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Juergen Gross <jgr...@suse.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Will Deacon <will.dea...@arm.com>
Cc: aligu...@amazon.com
Cc: daniel.gr...@iaik.tugraz.at
Cc: hu...@google.com
Cc: keesc...@google.com
---
arch/x86/mm/pti.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -187,6 +187,23 @@ pti_clone_pmds(unsigned long start, unsi
}
/*
+ * Clone the populated PMDs of the user shared fixmaps into the user space
+ * visible page table.
+ */
+static void __init pti_clone_user_shared(void)
+{
+ unsigned long bot, top;
+
+ bot = __fix_to_virt(FIX_USR_SHARED_BOTTOM);
+ top = __fix_to_virt(FIX_USR_SHARED_TOP) + PAGE_SIZE;
+
+ /* Top of the user shared block must be PMD-aligned. */
+ WARN_ON(top & ~PMD_MASK);
+
+ pti_clone_pmds(bot, top, 0);
+}
+
+/*
* Initialize kernel page table isolation
*/
void __init pti_init(void)
@@ -195,4 +212,6 @@ void __init pti_init(void)
return;
pr_info("enabled\n");
+
+ pti_clone_user_shared();
}
