queue-4.4/powerpc-pseries-use-the-security-flags-in-pseries_setup_rfi_flush.patch

   1 From foo@baz Mon 29 Apr 2019 11:38:37 AM CEST
   2 From: Michael Ellerman <mpe@ellerman.id.au>
   3 Date: Mon, 22 Apr 2019 00:20:02 +1000
   4 Subject: powerpc/pseries: Use the security flags in pseries_setup_rfi_flush()
   5 To: stable@vger.kernel.org, gregkh@linuxfoundation.org
   6 Cc: linuxppc-dev@ozlabs.org, diana.craciun@nxp.com, msuchanek@suse.de, npiggin@gmail.com, christophe.leroy@c-s.fr
   7 Message-ID: <20190421142037.21881-18-mpe@ellerman.id.au>
   8
   9 From: Michael Ellerman <mpe@ellerman.id.au>
  10
  11 commit 2e4a16161fcd324b1f9bf6cb6856529f7eaf0689 upstream.
  12
  13 Now that we have the security flags we can simplify the code in
  14 pseries_setup_rfi_flush() because the security flags have pessimistic
  15 defaults.
  16
  17 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
  18 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  19 ---
  20  arch/powerpc/platforms/pseries/setup.c |   27 ++++++++++++---------------
  21  1 file changed, 12 insertions(+), 15 deletions(-)
  22
  23 --- a/arch/powerpc/platforms/pseries/setup.c
  24 +++ b/arch/powerpc/platforms/pseries/setup.c
  25 @@ -541,30 +541,27 @@ void pseries_setup_rfi_flush(void)
  26         bool enable;
  27         long rc;
  28
  29 -       /* Enable by default */
  30 -       enable = true;
  31 -       types = L1D_FLUSH_FALLBACK;
  32 -
  33         rc = plpar_get_cpu_characteristics(&result);
  34 -       if (rc == H_SUCCESS) {
  35 +       if (rc == H_SUCCESS)
  36                 init_cpu_char_feature_flags(&result);
  37
  38 -               if (result.character & H_CPU_CHAR_L1D_FLUSH_TRIG2)
  39 -                       types |= L1D_FLUSH_MTTRIG;
  40 -               if (result.character & H_CPU_CHAR_L1D_FLUSH_ORI30)
  41 -                       types |= L1D_FLUSH_ORI;
  42 -
  43 -               if ((!(result.behaviour & H_CPU_BEHAV_L1D_FLUSH_PR)) ||
  44 -                   (!(result.behaviour & H_CPU_BEHAV_FAVOUR_SECURITY)))
  45 -                       enable = false;
  46 -       }
  47 -
  48         /*
  49          * We're the guest so this doesn't apply to us, clear it to simplify
  50          * handling of it elsewhere.
  51          */
  52         security_ftr_clear(SEC_FTR_L1D_FLUSH_HV);
  53
  54 +       types = L1D_FLUSH_FALLBACK;
  55 +
  56 +       if (security_ftr_enabled(SEC_FTR_L1D_FLUSH_TRIG2))
  57 +               types |= L1D_FLUSH_MTTRIG;
  58 +
  59 +       if (security_ftr_enabled(SEC_FTR_L1D_FLUSH_ORI30))
  60 +               types |= L1D_FLUSH_ORI;
  61 +
  62 +       enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) && \
  63 +                security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR);
  64 +
  65         setup_rfi_flush(types, enable);
  66  }
  67