Kirill A. Shutemov 0cfb151b93 x86/efi: Fix efi_call_phys_epilog() with CONFIG_X86_5LEVEL=y
commit cfe1957704 upstream.

Open-coded page table entry checks don't work correctly when we fold the
page table level at runtime.

pgd_present() on 4-level paging machine always returns true, but
open-coded version of the check may return false-negative result and
we silently skip the rest of the loop body in efi_call_phys_epilog().

Replace open-coded checks with proper helpers.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org # v4.12+
Fixes: 94133e46a0 ("x86/efi: Correct EFI identity mapping under 'efi=old_map' when KASLR is enabled")
Link: http://lkml.kernel.org/r/20180625120852.18300-1-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-03 11:25:05 +02:00
2018-07-03 11:25:03 +02:00
2018-06-26 08:06:33 +08:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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