releases/4.14.44/s390-crc32-vx-use-expoline-for-indirect-branches.patch

   1 From foo@baz Wed May 23 19:38:57 CEST 2018
   2 From: Martin Schwidefsky <schwidefsky@de.ibm.com>
   3 Date: Wed, 23 May 2018 18:22:03 +0200
   4 Subject: s390/crc32-vx: use expoline for indirect branches
   5 To: stable@vger.kernel.org
   6 Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
   7 Message-ID: <1527092529-24383-4-git-send-email-schwidefsky@de.ibm.com>
   8
   9 From: Martin Schwidefsky <schwidefsky@de.ibm.com>
  10
  11 [ Upstream commit 467a3bf219cee12259182c5cb4821f88fd518a51 ]
  12
  13 The return from the crc32_le_vgfm_16/crc32c_le_vgfm_16 and the
  14 crc32_be_vgfm_16 functions are done with "br %r14". These are indirect
  15 branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y.
  16
  17 Cc: stable@vger.kernel.org # 4.16
  18 Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
  19 Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
  20 Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
  21 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  22 ---
  23  arch/s390/crypto/crc32be-vx.S |    5 ++++-
  24  arch/s390/crypto/crc32le-vx.S |    4 +++-
  25  2 files changed, 7 insertions(+), 2 deletions(-)
  26
  27 --- a/arch/s390/crypto/crc32be-vx.S
  28 +++ b/arch/s390/crypto/crc32be-vx.S
  29 @@ -13,6 +13,7 @@
  30   */
  31
  32  #include <linux/linkage.h>
  33 +#include <asm/nospec-insn.h>
  34  #include <asm/vx-insn.h>
  35
  36  /* Vector register range containing CRC-32 constants */
  37 @@ -67,6 +68,8 @@
  38
  39  .previous
  40
  41 +       GEN_BR_THUNK %r14
  42 +
  43  .text
  44  /*
  45   * The CRC-32 function(s) use these calling conventions:
  46 @@ -203,6 +206,6 @@ ENTRY(crc32_be_vgfm_16)
  47
  48  .Ldone:
  49         VLGVF   %r2,%v2,3
  50 -       br      %r14
  51 +       BR_EX   %r14
  52
  53  .previous
  54 --- a/arch/s390/crypto/crc32le-vx.S
  55 +++ b/arch/s390/crypto/crc32le-vx.S
  56 @@ -14,6 +14,7 @@
  57   */
  58
  59  #include <linux/linkage.h>
  60 +#include <asm/nospec-insn.h>
  61  #include <asm/vx-insn.h>
  62
  63  /* Vector register range containing CRC-32 constants */
  64 @@ -76,6 +77,7 @@
  65
  66  .previous
  67
  68 +       GEN_BR_THUNK %r14
  69
  70  .text
  71
  72 @@ -264,6 +266,6 @@ crc32_le_vgfm_generic:
  73
  74  .Ldone:
  75         VLGVF   %r2,%v2,2
  76 -       br      %r14
  77 +       BR_EX   %r14
  78
  79  .previous