releases/4.19.43/0025-powerpc-speculation-Support-mitigations-cmdline-opti.patch

   1 From 1caa66c02b21ad771c6bfa38327c68ba308a633d Mon Sep 17 00:00:00 2001
   2 From: Josh Poimboeuf <jpoimboe@redhat.com>
   3 Date: Fri, 12 Apr 2019 15:39:30 -0500
   4 Subject: [PATCH 25/30] powerpc/speculation: Support 'mitigations=' cmdline
   5  option
   6
   7 commit 782e69efb3dfed6e8360bc612e8c7827a901a8f9 upstream
   8
   9 Configure powerpc CPU runtime speculation bug mitigations in accordance
  10 with the 'mitigations=' cmdline option.  This affects Meltdown, Spectre
  11 v1, Spectre v2, and Speculative Store Bypass.
  12
  13 The default behavior is unchanged.
  14
  15 Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
  16 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  17 Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86)
  18 Reviewed-by: Jiri Kosina <jkosina@suse.cz>
  19 Cc: Borislav Petkov <bp@alien8.de>
  20 Cc: "H . Peter Anvin" <hpa@zytor.com>
  21 Cc: Andy Lutomirski <luto@kernel.org>
  22 Cc: Peter Zijlstra <peterz@infradead.org>
  23 Cc: Jiri Kosina <jikos@kernel.org>
  24 Cc: Waiman Long <longman@redhat.com>
  25 Cc: Andrea Arcangeli <aarcange@redhat.com>
  26 Cc: Jon Masters <jcm@redhat.com>
  27 Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
  28 Cc: Paul Mackerras <paulus@samba.org>
  29 Cc: Michael Ellerman <mpe@ellerman.id.au>
  30 Cc: linuxppc-dev@lists.ozlabs.org
  31 Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
  32 Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
  33 Cc: linux-s390@vger.kernel.org
  34 Cc: Catalin Marinas <catalin.marinas@arm.com>
  35 Cc: Will Deacon <will.deacon@arm.com>
  36 Cc: linux-arm-kernel@lists.infradead.org
  37 Cc: linux-arch@vger.kernel.org
  38 Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  39 Cc: Tyler Hicks <tyhicks@canonical.com>
  40 Cc: Linus Torvalds <torvalds@linux-foundation.org>
  41 Cc: Randy Dunlap <rdunlap@infradead.org>
  42 Cc: Steven Price <steven.price@arm.com>
  43 Cc: Phil Auld <pauld@redhat.com>
  44 Link: https://lkml.kernel.org/r/245a606e1a42a558a310220312d9b6adb9159df6.1555085500.git.jpoimboe@redhat.com
  45 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  46 ---
  47  Documentation/admin-guide/kernel-parameters.txt | 9 +++++----
  48  arch/powerpc/kernel/security.c                  | 6 +++---
  49  arch/powerpc/kernel/setup_64.c                  | 2 +-
  50  3 files changed, 9 insertions(+), 8 deletions(-)
  51
  52 diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
  53 index 31c17532c219..49aa191979c1 100644
  54 --- a/Documentation/admin-guide/kernel-parameters.txt
  55 +++ b/Documentation/admin-guide/kernel-parameters.txt
  56 @@ -2503,7 +2503,7 @@
  57                         http://repo.or.cz/w/linux-2.6/mini2440.git
  58
  59         mitigations=
  60 -                       [X86] Control optional mitigations for CPU
  61 +                       [X86,PPC] Control optional mitigations for CPU
  62                         vulnerabilities.  This is a set of curated,
  63                         arch-independent options, each of which is an
  64                         aggregation of existing arch-specific options.
  65 @@ -2512,10 +2512,11 @@
  66                                 Disable all optional CPU mitigations.  This
  67                                 improves system performance, but it may also
  68                                 expose users to several CPU vulnerabilities.
  69 -                               Equivalent to: nopti [X86]
  70 -                                              nospectre_v2 [X86]
  71 +                               Equivalent to: nopti [X86,PPC]
  72 +                                              nospectre_v1 [PPC]
  73 +                                              nospectre_v2 [X86,PPC]
  74                                                spectre_v2_user=off [X86]
  75 -                                              spec_store_bypass_disable=off [X86]
  76 +                                              spec_store_bypass_disable=off [X86,PPC]
  77                                                l1tf=off [X86]
  78
  79                         auto (default)
  80 diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
  81 index 1341325599a7..4ccbf611a3c5 100644
  82 --- a/arch/powerpc/kernel/security.c
  83 +++ b/arch/powerpc/kernel/security.c
  84 @@ -56,7 +56,7 @@ void setup_barrier_nospec(void)
  85         enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
  86                  security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
  87
  88 -       if (!no_nospec)
  89 +       if (!no_nospec && !cpu_mitigations_off())
  90                 enable_barrier_nospec(enable);
  91  }
  92
  93 @@ -115,7 +115,7 @@ static int __init handle_nospectre_v2(char *p)
  94  early_param("nospectre_v2", handle_nospectre_v2);
  95  void setup_spectre_v2(void)
  96  {
  97 -       if (no_spectrev2)
  98 +       if (no_spectrev2 || cpu_mitigations_off())
  99                 do_btb_flush_fixups();
 100         else
 101                 btb_flush_enabled = true;
 102 @@ -299,7 +299,7 @@ void setup_stf_barrier(void)
 103
 104         stf_enabled_flush_types = type;
 105
 106 -       if (!no_stf_barrier)
 107 +       if (!no_stf_barrier && !cpu_mitigations_off())
 108                 stf_barrier_enable(enable);
 109  }
 110
 111 diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
 112 index faf00222b324..eaf7300be5ab 100644
 113 --- a/arch/powerpc/kernel/setup_64.c
 114 +++ b/arch/powerpc/kernel/setup_64.c
 115 @@ -955,7 +955,7 @@ void setup_rfi_flush(enum l1d_flush_type types, bool enable)
 116
 117         enabled_flush_types = types;
 118
 119 -       if (!no_rfi_flush)
 120 +       if (!no_rfi_flush && !cpu_mitigations_off())
 121                 rfi_flush_enable(enable);
 122  }
 123
 124 --
 125 2.21.0
 126