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| author | Dave Hansen <dave.hansen@linux.intel.com> | 2018-01-06 18:41:14 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-01-08 17:29:18 +0100 |
| commit | 262b6b30087246abf09d6275eb0c0dc421bcbe38 (patch) | |
| tree | ea807ff4377f68fa4c1d66f7577895503e2c4869 /arch | |
| parent | 61dc0f555b5c761cdafb0ba5bd41ecf22d68a4c4 (diff) | |
| download | linux-262b6b30087246abf09d6275eb0c0dc421bcbe38.tar.gz linux-262b6b30087246abf09d6275eb0c0dc421bcbe38.tar.bz2 linux-262b6b30087246abf09d6275eb0c0dc421bcbe38.zip | |
x86/tboot: Unbreak tboot with PTI enabled
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.
Fixes: 385ce0ea4c07 ("x86/mm/pti: Add Kconfig")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jeff Law <law@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org>
Cc: David" <dwmw@amazon.co.uk>
Cc: Nick Clifton <nickc@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180108102805.GK25546@redhat.com
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/tboot.c | 1 |
1 files changed, 1 insertions, 0 deletions
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; |