queue-4.14/powerpc-perf-fix-mmcra-corruption-by-bhrb_filter.patch

   1 From 3202e35ec1c8fc19cea24253ff83edf702a60a02 Mon Sep 17 00:00:00 2001
   2 From: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
   3 Date: Sat, 11 May 2019 08:12:17 +0530
   4 Subject: powerpc/perf: Fix MMCRA corruption by bhrb_filter
   5
   6 From: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
   7
   8 commit 3202e35ec1c8fc19cea24253ff83edf702a60a02 upstream.
   9
  10 Consider a scenario where user creates two events:
  11
  12   1st event:
  13     attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
  14     attr.branch_sample_type = PERF_SAMPLE_BRANCH_ANY;
  15     fd = perf_event_open(attr, 0, 1, -1, 0);
  16
  17   This sets cpuhw->bhrb_filter to 0 and returns valid fd.
  18
  19   2nd event:
  20     attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
  21     attr.branch_sample_type = PERF_SAMPLE_BRANCH_CALL;
  22     fd = perf_event_open(attr, 0, 1, -1, 0);
  23
  24   It overrides cpuhw->bhrb_filter to -1 and returns with error.
  25
  26 Now if power_pmu_enable() gets called by any path other than
  27 power_pmu_add(), ppmu->config_bhrb(-1) will set MMCRA to -1.
  28
  29 Fixes: 3925f46bb590 ("powerpc/perf: Enable branch stack sampling framework")
  30 Cc: stable@vger.kernel.org # v3.10+
  31 Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
  32 Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
  33 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
  34 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  35
  36 ---
  37  arch/powerpc/perf/core-book3s.c |    6 ++++--
  38  arch/powerpc/perf/power8-pmu.c  |    3 +++
  39  arch/powerpc/perf/power9-pmu.c  |    3 +++
  40  3 files changed, 10 insertions(+), 2 deletions(-)
  41
  42 --- a/arch/powerpc/perf/core-book3s.c
  43 +++ b/arch/powerpc/perf/core-book3s.c
  44 @@ -1845,6 +1845,7 @@ static int power_pmu_event_init(struct p
  45         int n;
  46         int err;
  47         struct cpu_hw_events *cpuhw;
  48 +       u64 bhrb_filter;
  49
  50         if (!ppmu)
  51                 return -ENOENT;
  52 @@ -1941,13 +1942,14 @@ static int power_pmu_event_init(struct p
  53         err = power_check_constraints(cpuhw, events, cflags, n + 1);
  54
  55         if (has_branch_stack(event)) {
  56 -               cpuhw->bhrb_filter = ppmu->bhrb_filter_map(
  57 +               bhrb_filter = ppmu->bhrb_filter_map(
  58                                         event->attr.branch_sample_type);
  59
  60 -               if (cpuhw->bhrb_filter == -1) {
  61 +               if (bhrb_filter == -1) {
  62                         put_cpu_var(cpu_hw_events);
  63                         return -EOPNOTSUPP;
  64                 }
  65 +               cpuhw->bhrb_filter = bhrb_filter;
  66         }
  67
  68         put_cpu_var(cpu_hw_events);
  69 --- a/arch/powerpc/perf/power8-pmu.c
  70 +++ b/arch/powerpc/perf/power8-pmu.c
  71 @@ -29,6 +29,7 @@ enum {
  72  #define        POWER8_MMCRA_IFM1               0x0000000040000000UL
  73  #define        POWER8_MMCRA_IFM2               0x0000000080000000UL
  74  #define        POWER8_MMCRA_IFM3               0x00000000C0000000UL
  75 +#define        POWER8_MMCRA_BHRB_MASK          0x00000000C0000000UL
  76
  77  /* PowerISA v2.07 format attribute structure*/
  78  extern struct attribute_group isa207_pmu_format_group;
  79 @@ -179,6 +180,8 @@ static u64 power8_bhrb_filter_map(u64 br
  80
  81  static void power8_config_bhrb(u64 pmu_bhrb_filter)
  82  {
  83 +       pmu_bhrb_filter &= POWER8_MMCRA_BHRB_MASK;
  84 +
  85         /* Enable BHRB filter in PMU */
  86         mtspr(SPRN_MMCRA, (mfspr(SPRN_MMCRA) | pmu_bhrb_filter));
  87  }
  88 --- a/arch/powerpc/perf/power9-pmu.c
  89 +++ b/arch/powerpc/perf/power9-pmu.c
  90 @@ -100,6 +100,7 @@ enum {
  91  #define POWER9_MMCRA_IFM1              0x0000000040000000UL
  92  #define POWER9_MMCRA_IFM2              0x0000000080000000UL
  93  #define POWER9_MMCRA_IFM3              0x00000000C0000000UL
  94 +#define POWER9_MMCRA_BHRB_MASK         0x00000000C0000000UL
  95
  96  /* PowerISA v2.07 format attribute structure*/
  97  extern struct attribute_group isa207_pmu_format_group;
  98 @@ -289,6 +290,8 @@ static u64 power9_bhrb_filter_map(u64 br
  99
 100  static void power9_config_bhrb(u64 pmu_bhrb_filter)
 101  {
 102 +       pmu_bhrb_filter &= POWER9_MMCRA_BHRB_MASK;
 103 +
 104         /* Enable BHRB filter in PMU */
 105         mtspr(SPRN_MMCRA, (mfspr(SPRN_MMCRA) | pmu_bhrb_filter));
 106  }