1. 10 9月, 2018 2 次提交
  2. 09 9月, 2018 1 次提交
  3. 03 9月, 2018 29 次提交
  4. 02 9月, 2018 5 次提交
  5. 01 9月, 2018 2 次提交
  6. 31 8月, 2018 1 次提交
    • J
      x86/efi: Load fixmap GDT in efi_call_phys_epilog() · eeb89e2b
      Joerg Roedel 提交于
      When PTI is enabled on x86-32 the kernel uses the GDT mapped in the fixmap
      for the simple reason that this address is also mapped for user-space.
      
      The efi_call_phys_prolog()/efi_call_phys_epilog() wrappers change the GDT
      to call EFI runtime services and switch back to the kernel GDT when they
      return. But the switch-back uses the writable GDT, not the fixmap GDT.
      
      When that happened and and the CPU returns to user-space it switches to the
      user %cr3 and tries to restore user segment registers. This fails because
      the writable GDT is not mapped in the user page-table, and without a GDT
      the fault handlers also can't be launched. The result is a triple fault and
      reboot of the machine.
      
      Fix that by restoring the GDT back to the fixmap GDT which is also mapped
      in the user page-table.
      
      Fixes: 7757d607 x86/pti: ('Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32')
      Reported-by: NGuenter Roeck <linux@roeck-us.net>
      Signed-off-by: NJoerg Roedel <jroedel@suse.de>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Tested-by: NGuenter Roeck <linux@roeck-us.net>
      Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Pavel Machek <pavel@ucw.cz>
      Cc: hpa@zytor.com
      Cc: linux-efi@vger.kernel.org
      Link: https://lkml.kernel.org/r/1535702738-10971-1-git-send-email-joro@8bytes.org
      eeb89e2b