releases/4.14.110/powerpc-64-disable-the-speculation-barrier-from-the-command-line.patch

   1 From foo@baz Fri Mar 29 15:53:50 CET 2019
   2 From: Michael Ellerman <mpe@ellerman.id.au>
   3 Date: Fri, 29 Mar 2019 22:25:56 +1100
   4 Subject: powerpc/64: Disable the speculation barrier from the command line
   5 To: stable@vger.kernel.org, gregkh@linuxfoundation.org
   6 Cc: linuxppc-dev@ozlabs.org, diana.craciun@nxp.com, msuchanek@suse.de, christophe.leroy@c-s.fr
   7 Message-ID: <20190329112620.14489-9-mpe@ellerman.id.au>
   8
   9 From: Diana Craciun <diana.craciun@nxp.com>
  10
  11 commit cf175dc315f90185128fb061dc05b6fbb211aa2f upstream.
  12
  13 The speculation barrier can be disabled from the command line
  14 with the parameter: "nospectre_v1".
  15
  16 Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
  17 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
  18 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  19 ---
  20  arch/powerpc/kernel/security.c |   12 +++++++++++-
  21  1 file changed, 11 insertions(+), 1 deletion(-)
  22
  23 --- a/arch/powerpc/kernel/security.c
  24 +++ b/arch/powerpc/kernel/security.c
  25 @@ -16,6 +16,7 @@
  26  unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
  27
  28  bool barrier_nospec_enabled;
  29 +static bool no_nospec;
  30
  31  static void enable_barrier_nospec(bool enable)
  32  {
  33 @@ -42,9 +43,18 @@ void setup_barrier_nospec(void)
  34         enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
  35                  security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
  36
  37 -       enable_barrier_nospec(enable);
  38 +       if (!no_nospec)
  39 +               enable_barrier_nospec(enable);
  40  }
  41
  42 +static int __init handle_nospectre_v1(char *p)
  43 +{
  44 +       no_nospec = true;
  45 +
  46 +       return 0;
  47 +}
  48 +early_param("nospectre_v1", handle_nospectre_v1);
  49 +
  50  #ifdef CONFIG_DEBUG_FS
  51  static int barrier_nospec_set(void *data, u64 val)
  52  {