queue-4.4/powerpc-rfi-flush-move-the-logic-to-avoid-a-redo-into-the-debugfs-code.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 00:19:50 +1000
   4 Subject: powerpc/rfi-flush: Move the logic to avoid a redo into the debugfs code
   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: <20190421142037.21881-6-mpe@ellerman.id.au>
   8
   9 From: Michael Ellerman <mpe@ellerman.id.au>
  10
  11 commit 1e2a9fc7496955faacbbed49461d611b704a7505 upstream.
  12
  13 rfi_flush_enable() includes a check to see if we're already
  14 enabled (or disabled), and in that case does nothing.
  15
  16 But that means calling setup_rfi_flush() a 2nd time doesn't actually
  17 work, which is a bit confusing.
  18
  19 Move that check into the debugfs code, where it really belongs.
  20
  21 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
  22 Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
  23 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25 ---
  26  arch/powerpc/kernel/setup_64.c |   13 ++++++++-----
  27  1 file changed, 8 insertions(+), 5 deletions(-)
  28
  29 --- a/arch/powerpc/kernel/setup_64.c
  30 +++ b/arch/powerpc/kernel/setup_64.c
  31 @@ -873,9 +873,6 @@ static void do_nothing(void *unused)
  32
  33  void rfi_flush_enable(bool enable)
  34  {
  35 -       if (rfi_flush == enable)
  36 -               return;
  37 -
  38         if (enable) {
  39                 do_rfi_flush_fixups(enabled_flush_types);
  40                 on_each_cpu(do_nothing, NULL, 1);
  41 @@ -929,13 +926,19 @@ void __init setup_rfi_flush(enum l1d_flu
  42  #ifdef CONFIG_DEBUG_FS
  43  static int rfi_flush_set(void *data, u64 val)
  44  {
  45 +       bool enable;
  46 +
  47         if (val == 1)
  48 -               rfi_flush_enable(true);
  49 +               enable = true;
  50         else if (val == 0)
  51 -               rfi_flush_enable(false);
  52 +               enable = false;
  53         else
  54                 return -EINVAL;
  55
  56 +       /* Only do anything if we're changing state */
  57 +       if (enable != rfi_flush)
  58 +               rfi_flush_enable(enable);
  59 +
  60         return 0;
  61  }
  62