queue-6.6/x86-cpu-amd-carve-out-the-erratum-1386-fix.patch

   1 From 6fa756f7aa84827d2e839b8a1ef4360092ecf23d Mon Sep 17 00:00:00 2001
   2 From: Sasha Levin <sashal@kernel.org>
   3 Date: Wed, 1 Nov 2023 11:14:59 +0100
   4 Subject: x86/CPU/AMD: Carve out the erratum 1386 fix
   5
   6 From: Borislav Petkov (AMD) <bp@alien8.de>
   7
   8 [ Upstream commit a7c32a1ae9ee43abfe884f5af376877c4301d166 ]
   9
  10 Call it on the affected CPU generations.
  11
  12 No functional changes.
  13
  14 Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
  15 Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
  16 Link: http://lore.kernel.org/r/20231120104152.13740-3-bp@alien8.de
  17 Stable-dep-of: c7b2edd8377b ("perf/x86/amd/core: Update and fix stalled-cycles-* events for Zen 2 and later")
  18 Signed-off-by: Sasha Levin <sashal@kernel.org>
  19 ---
  20  arch/x86/kernel/cpu/amd.c | 24 +++++++++++++++---------
  21  1 file changed, 15 insertions(+), 9 deletions(-)
  22
  23 diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
  24 index 5391385707b3f..28c3a1045b060 100644
  25 --- a/arch/x86/kernel/cpu/amd.c
  26 +++ b/arch/x86/kernel/cpu/amd.c
  27 @@ -988,6 +988,19 @@ static void init_amd_bd(struct cpuinfo_x86 *c)
  28         clear_rdrand_cpuid_bit(c);
  29  }
  30
  31 +static void fix_erratum_1386(struct cpuinfo_x86 *c)
  32 +{
  33 +       /*
  34 +        * Work around Erratum 1386.  The XSAVES instruction malfunctions in
  35 +        * certain circumstances on Zen1/2 uarch, and not all parts have had
  36 +        * updated microcode at the time of writing (March 2023).
  37 +        *
  38 +        * Affected parts all have no supervisor XSAVE states, meaning that
  39 +        * the XSAVEC instruction (which works fine) is equivalent.
  40 +        */
  41 +       clear_cpu_cap(c, X86_FEATURE_XSAVES);
  42 +}
  43 +
  44  void init_spectral_chicken(struct cpuinfo_x86 *c)
  45  {
  46  #ifdef CONFIG_CPU_UNRET_ENTRY
  47 @@ -1008,15 +1021,6 @@ void init_spectral_chicken(struct cpuinfo_x86 *c)
  48                 }
  49         }
  50  #endif
  51 -       /*
  52 -        * Work around Erratum 1386.  The XSAVES instruction malfunctions in
  53 -        * certain circumstances on Zen1/2 uarch, and not all parts have had
  54 -        * updated microcode at the time of writing (March 2023).
  55 -        *
  56 -        * Affected parts all have no supervisor XSAVE states, meaning that
  57 -        * the XSAVEC instruction (which works fine) is equivalent.
  58 -        */
  59 -       clear_cpu_cap(c, X86_FEATURE_XSAVES);
  60  }
  61
  62  static void init_amd_zn(struct cpuinfo_x86 *c)
  63 @@ -1085,10 +1089,12 @@ static void zenbleed_check(struct cpuinfo_x86 *c)
  64
  65  static void init_amd_zen(struct cpuinfo_x86 *c)
  66  {
  67 +       fix_erratum_1386(c);
  68  }
  69
  70  static void init_amd_zen2(struct cpuinfo_x86 *c)
  71  {
  72 +       fix_erratum_1386(c);
  73  }
  74
  75  static void init_amd_zen3(struct cpuinfo_x86 *c)
  76 --
  77 2.43.0
  78