From: Andy Lutomirski <luto@kernel.org>

Date: Tue, 12 Dec 2017 07:56:43 -0800

Subject: x86/mm/64: Improve the memory map documentation

Git-commit: 5a7ccf4754fb3660569a6de52ba7f7fc3dfaf280

Patch-mainline: v4.15-rc5

References: bsc#1068032 CVE-2017-5754

The old docs had the vsyscall range wrong and were missing the fixmap.

Fix both.

There used to be 8 MB reserved for future vsyscalls, but that's long gone.

Signed-off-by: Andy Lutomirski <luto@kernel.org>

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Cc: Borislav Petkov <bp@alien8.de>

Cc: Brian Gerst <brgerst@gmail.com>

Cc: Dave Hansen <dave.hansen@intel.com>

Cc: Dave Hansen <dave.hansen@linux.intel.com>

Cc: David Laight <David.Laight@aculab.com>

Cc: H. Peter Anvin <hpa@zytor.com>

Cc: Josh Poimboeuf <jpoimboe@redhat.com>

Cc: Juergen Gross <jgross@suse.com>

Cc: Kees Cook <keescook@chromium.org>

Cc: Kirill A. Shutemov <kirill@shutemov.name>

Cc: Linus Torvalds <torvalds@linux-foundation.org>

Cc: Peter Zijlstra <peterz@infradead.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Acked-by: Borislav Petkov <bp@suse.de>

---

 Documentation/x86/x86_64/mm.txt | 10 ++++++----

 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt

index 3448e675b462..83ca5a3b90ac 100644

--- a/Documentation/x86/x86_64/mm.txt

+++ b/Documentation/x86/x86_64/mm.txt

@@ -19,8 +19,9 @@ ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks

 ffffffef00000000 - fffffffeffffffff (=64 GB) EFI region mapping space

 ... unused hole ...

 ffffffff80000000 - ffffffff9fffffff (=512 MB)  kernel text mapping, from phys 0

-ffffffffa0000000 - ffffffffff5fffff (=1526 MB) module mapping space (variable)

-ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls

+ffffffffa0000000 - [fixmap start]   (~1526 MB) module mapping space (variable)

+[fixmap start]   - ffffffffff5fffff kernel-internal fixmap range

+ffffffffff600000 - ffffffffff600fff (=4 kB) legacy vsyscall ABI

 ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole

 Virtual memory map with 5 level page tables:

@@ -41,8 +42,9 @@ ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks

 ffffffef00000000 - fffffffeffffffff (=64 GB) EFI region mapping space

 ... unused hole ...

 ffffffff80000000 - ffffffff9fffffff (=512 MB)  kernel text mapping, from phys 0

-ffffffffa0000000 - ffffffffff5fffff (=1526 MB) module mapping space

-ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls

+ffffffffa0000000 - [fixmap start]   (~1526 MB) module mapping space

+[fixmap start]   - ffffffffff5fffff kernel-internal fixmap range

+ffffffffff600000 - ffffffffff600fff (=4 kB) legacy vsyscall ABI

 ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole

 Architecture defines a 64-bit virtual address. Implementations can support