On Mon, 8 Jan 2018, Andrea Arcangeli wrote: > On Fri, Jan 05, 2018 at 10:59:28AM +0100, Thomas Gleixner wrote: > I sent you a better version of the efi_64.c fix from Jiri privately > and you still miss the tboot fix in linux-tip so you still got a boot > failure to fix there.
Missed that in the pile ... > This is incremental with > https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/log/?h=WIP.x86/pti > where the "Unbreak EFI old_memmap" fix is applied. > > I respinned it after doing the more correct fix in this case too (same > as the efi_64.c improvement) while leaving the attribution to the fix > to Dave as he did the hard part. Thanks for resending it. > >From 0c480d1eeabd56379144a4ed6b6fb24f3b84e40e Mon Sep 17 00:00:00 2001 > From: Dave Hansen <dave.han...@linux.intel.com> > Date: Sat, 6 Jan 2018 18:41:14 +0100 > Subject: [PATCH 1/1] x86/kaiser/efi: unbreak tboot > > This is another case similar to what EFI does: create a new set of > page tables, map some code at a low address, and jump to it. PTI > mistakes this low address for userspace and mistakenly marks it > non-executable in an effort to make it unusable for userspace. Undo > the poison to allow execution. > > Signed-off-by: Dave Hansen <dave.han...@linux.intel.com> > Cc: Ning Sun <ning....@intel.com> > Cc: Thomas Gleixner <t...@linutronix.de> > Cc: Ingo Molnar <mi...@redhat.com> > Cc: "H. Peter Anvin" <h...@zytor.com> > Cc: x...@kernel.org > Cc: tboot-de...@lists.sourceforge.net > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Andrea Arcangeli <aarca...@redhat.com> > --- > arch/x86/kernel/tboot.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c > index a4eb27918ceb..75869a4b6c41 100644 > --- a/arch/x86/kernel/tboot.c > +++ b/arch/x86/kernel/tboot.c > @@ -127,6 +127,7 @@ static int map_tboot_page(unsigned long vaddr, unsigned > long pfn, > p4d = p4d_alloc(&tboot_mm, pgd, vaddr); > if (!p4d) > return -1; > + pgd->pgd &= ~_PAGE_NX; > pud = pud_alloc(&tboot_mm, p4d, vaddr); > if (!pud) > return -1; > > If I can help and assist in any other way let me know. > > Thanks, > Andrea >
