patches/kernel/0086-x86-boot-Relocate-definition-of-the-initial-state-of.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
   3 Date: Fri, 27 Oct 2017 13:25:29 -0700
   4 Subject: [PATCH] x86/boot: Relocate definition of the initial state of CR0
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 CVE-2017-5754
  10
  11 Both head_32.S and head_64.S utilize the same value to initialize the
  12 control register CR0. Also, other parts of the kernel might want to access
  13 this initial definition (e.g., emulation code for User-Mode Instruction
  14 Prevention uses this state to provide a sane dummy value for CR0 when
  15 emulating the smsw instruction). Thus, relocate this definition to a
  16 header file from which it can be conveniently accessed.
  17
  18 Suggested-by: Borislav Petkov <bp@alien8.de>
  19 Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
  20 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  21 Reviewed-by: Borislav Petkov <bp@suse.de>
  22 Reviewed-by: Andy Lutomirski <luto@kernel.org>
  23 Cc: "Michael S. Tsirkin" <mst@redhat.com>
  24 Cc: Peter Zijlstra <peterz@infradead.org>
  25 Cc: Dave Hansen <dave.hansen@linux.intel.com>
  26 Cc: ricardo.neri@intel.com
  27 Cc: linux-mm@kvack.org
  28 Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
  29 Cc: Huang Rui <ray.huang@amd.com>
  30 Cc: Shuah Khan <shuah@kernel.org>
  31 Cc: linux-arch@vger.kernel.org
  32 Cc: Jonathan Corbet <corbet@lwn.net>
  33 Cc: Jiri Slaby <jslaby@suse.cz>
  34 Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com>
  35 Cc: Denys Vlasenko <dvlasenk@redhat.com>
  36 Cc: Chris Metcalf <cmetcalf@mellanox.com>
  37 Cc: Brian Gerst <brgerst@gmail.com>
  38 Cc: Josh Poimboeuf <jpoimboe@redhat.com>
  39 Cc: Chen Yucong <slaoub@gmail.com>
  40 Cc: Vlastimil Babka <vbabka@suse.cz>
  41 Cc: Dave Hansen <dave.hansen@intel.com>
  42 Cc: Andy Lutomirski <luto@amacapital.net>
  43 Cc: Masami Hiramatsu <mhiramat@kernel.org>
  44 Cc: Paolo Bonzini <pbonzini@redhat.com>
  45 Cc: Andrew Morton <akpm@linux-foundation.org>
  46 Cc: Linus Torvalds <torvalds@linux-foundation.org>
  47 Link: https://lkml.kernel.org/r/1509135945-13762-3-git-send-email-ricardo.neri-calderon@linux.intel.com
  48
  49 (cherry picked from commit b0ce5b8c95c83a7b98c679b117e3d6ae6f97154b)
  50 Signed-off-by: Andy Whitcroft <apw@canonical.com>
  51 Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
  52 (cherry picked from commit 27c31a88c22edab269abe17c0ac7db0351d26c5f)
  53 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  54 ---
  55  arch/x86/include/uapi/asm/processor-flags.h | 3 +++
  56  arch/x86/kernel/head_32.S                   | 3 ---
  57  arch/x86/kernel/head_64.S                   | 3 ---
  58  3 files changed, 3 insertions(+), 6 deletions(-)
  59
  60 diff --git a/arch/x86/include/uapi/asm/processor-flags.h b/arch/x86/include/uapi/asm/processor-flags.h
  61 index 185f3d10c194..39946d0a1d41 100644
  62 --- a/arch/x86/include/uapi/asm/processor-flags.h
  63 +++ b/arch/x86/include/uapi/asm/processor-flags.h
  64 @@ -151,5 +151,8 @@
  65  #define CX86_ARR_BASE  0xc4
  66  #define CX86_RCR_BASE  0xdc
  67
  68 +#define CR0_STATE      (X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \
  69 +                        X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \
  70 +                        X86_CR0_PG)
  71
  72  #endif /* _UAPI_ASM_X86_PROCESSOR_FLAGS_H */
  73 diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
  74 index 337a65377baf..7bbcdb1ea31a 100644
  75 --- a/arch/x86/kernel/head_32.S
  76 +++ b/arch/x86/kernel/head_32.S
  77 @@ -213,9 +213,6 @@ ENTRY(startup_32_smp)
  78  #endif
  79
  80  .Ldefault_entry:
  81 -#define CR0_STATE      (X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \
  82 -                        X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \
  83 -                        X86_CR0_PG)
  84         movl $(CR0_STATE & ~X86_CR0_PG),%eax
  85         movl %eax,%cr0
  86
  87 diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
  88 index a2d8541b1da4..4117c1e0b3d2 100644
  89 --- a/arch/x86/kernel/head_64.S
  90 +++ b/arch/x86/kernel/head_64.S
  91 @@ -137,9 +137,6 @@ ENTRY(secondary_startup_64)
  92  1:     wrmsr                           /* Make changes effective */
  93
  94         /* Setup cr0 */
  95 -#define CR0_STATE      (X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \
  96 -                        X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \
  97 -                        X86_CR0_PG)
  98         movl    $CR0_STATE, %eax
  99         /* Make changes effective */
 100         movq    %rax, %cr0
 101 --
 102 2.14.2
 103