patches/kernel/0172-x86-doc-Remove-obvious-weirdnesses-from-the-x86-MM-l.patch

   1 From 8ae2a4b32fa54630c9b3c2302aa8faeb5a513e98 Mon Sep 17 00:00:00 2001
   2 From: Peter Zijlstra <peterz@infradead.org>
   3 Date: Tue, 5 Dec 2017 13:34:54 +0100
   4 Subject: [PATCH 172/242] x86/doc: Remove obvious weirdnesses from the x86 MM
   5  layout documentation
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 CVE-2017-5754
  11
  12 Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
  13 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  14 Cc: Andy Lutomirski <luto@kernel.org>
  15 Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
  16 Cc: Borislav Petkov <bp@alien8.de>
  17 Cc: Brian Gerst <brgerst@gmail.com>
  18 Cc: Dave Hansen <dave.hansen@linux.intel.com>
  19 Cc: David Laight <David.Laight@aculab.com>
  20 Cc: Denys Vlasenko <dvlasenk@redhat.com>
  21 Cc: Eduardo Valentin <eduval@amazon.com>
  22 Cc: Greg KH <gregkh@linuxfoundation.org>
  23 Cc: H. Peter Anvin <hpa@zytor.com>
  24 Cc: Josh Poimboeuf <jpoimboe@redhat.com>
  25 Cc: Juergen Gross <jgross@suse.com>
  26 Cc: Linus Torvalds <torvalds@linux-foundation.org>
  27 Cc: Peter Zijlstra <peterz@infradead.org>
  28 Cc: Will Deacon <will.deacon@arm.com>
  29 Cc: aliguori@amazon.com
  30 Cc: daniel.gruss@iaik.tugraz.at
  31 Cc: hughd@google.com
  32 Cc: keescook@google.com
  33 Cc: linux-mm@kvack.org
  34 Signed-off-by: Ingo Molnar <mingo@kernel.org>
  35 (cherry picked from commit e8ffe96e5933d417195268478479933d56213a3f)
  36 Signed-off-by: Andy Whitcroft <apw@canonical.com>
  37 Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
  38 (cherry picked from commit d9012133906878a404cf47acc168ff9e4b10e379)
  39 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  40 ---
  41  Documentation/x86/x86_64/mm.txt | 12 +++---------
  42  1 file changed, 3 insertions(+), 9 deletions(-)
  43
  44 diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt
  45 index 83ca5a3b90ac..63a41671d25b 100644
  46 --- a/Documentation/x86/x86_64/mm.txt
  47 +++ b/Documentation/x86/x86_64/mm.txt
  48 @@ -1,6 +1,4 @@
  49
  50 -<previous description obsolete, deleted>
  51 -
  52  Virtual memory map with 4 level page tables:
  53
  54  0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm
  55 @@ -49,8 +47,9 @@ ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
  56
  57  Architecture defines a 64-bit virtual address. Implementations can support
  58  less. Currently supported are 48- and 57-bit virtual addresses. Bits 63
  59 -through to the most-significant implemented bit are set to either all ones
  60 -or all zero. This causes hole between user space and kernel addresses.
  61 +through to the most-significant implemented bit are sign extended.
  62 +This causes hole between user space and kernel addresses if you interpret them
  63 +as unsigned.
  64
  65  The direct mapping covers all memory in the system up to the highest
  66  memory address (this means in some cases it can also include PCI memory
  67 @@ -60,9 +59,6 @@ vmalloc space is lazily synchronized into the different PML4/PML5 pages of
  68  the processes using the page fault handler, with init_top_pgt as
  69  reference.
  70
  71 -Current X86-64 implementations support up to 46 bits of address space (64 TB),
  72 -which is our current limit. This expands into MBZ space in the page tables.
  73 -
  74  We map EFI runtime services in the 'efi_pgd' PGD in a 64Gb large virtual
  75  memory window (this size is arbitrary, it can be raised later if needed).
  76  The mappings are not part of any other kernel PGD and are only available
  77 @@ -74,5 +70,3 @@ following fixmap section.
  78  Note that if CONFIG_RANDOMIZE_MEMORY is enabled, the direct mapping of all
  79  physical memory, vmalloc/ioremap space and virtual memory map are randomized.
  80  Their order is preserved but their base will be offset early at boot time.
  81 -
  82 --Andi Kleen, Jul 2004
  83 --
  84 2.14.2
  85