perf/x86: Fix offcore_rsp valid mask for SNB/IVB

The valid mask for both offcore_response_0 and
offcore_response_1 was wrong for SNB/SNB-EP,
IVB/IVB-EP. It was possible to write to
reserved bit and cause a GP fault crashing
the kernel.

This patch fixes the problem by correctly marking the
reserved bits in the valid mask for all the processors
mentioned above.

A distinction between desktop and server parts is introduced
because bits 24-30 are only available on the server parts.

This version of the  patch is just a rebase to perf/urgent tree
and should apply to older kernels as well.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: jolsa@redhat.com
Cc: gregkh@linuxfoundation.org
Cc: security@kernel.org
Cc: ak@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 16 insertions, 4 deletions

diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index dab7580c47ae..cc45deb791b0 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -153,8 +153,14 @@ static struct event_constraint intel_gen_event_constraints[] __read_mostly =
 };
 
 static struct extra_reg intel_snb_extra_regs[] __read_mostly = {
-        INTEL_EVENT_EXTRA_REG(0xb7, MSR_OFFCORE_RSP_0, 0x3fffffffffull, RSP_0),
-        INTEL_EVENT_EXTRA_REG(0xbb, MSR_OFFCORE_RSP_1, 0x3fffffffffull, RSP_1),
+        INTEL_EVENT_EXTRA_REG(0xb7, MSR_OFFCORE_RSP_0, 0x3f807f8fffull, RSP_0),
+        INTEL_EVENT_EXTRA_REG(0xbb, MSR_OFFCORE_RSP_1, 0x3f807f8fffull, RSP_1),
+        EVENT_EXTRA_END
+};
+
+static struct extra_reg intel_snbep_extra_regs[] __read_mostly = {
+        INTEL_EVENT_EXTRA_REG(0xb7, MSR_OFFCORE_RSP_0, 0x3fffff8fffull, RSP_0),
+        INTEL_EVENT_EXTRA_REG(0xbb, MSR_OFFCORE_RSP_1, 0x3fffff8fffull, RSP_1),
         EVENT_EXTRA_END
 };
 
@@ -2097,7 +2103,10 @@ __init int intel_pmu_init(void)
                 x86_pmu.event_constraints = intel_snb_event_constraints;
                 x86_pmu.pebs_constraints = intel_snb_pebs_event_constraints;
                 x86_pmu.pebs_aliases = intel_pebs_aliases_snb;
-                x86_pmu.extra_regs = intel_snb_extra_regs;
+                if (boot_cpu_data.x86_model == 45)
+                        x86_pmu.extra_regs = intel_snbep_extra_regs;
+                else
+                        x86_pmu.extra_regs = intel_snb_extra_regs;
                 /* all extra regs are per-cpu when HT is on */
                 x86_pmu.er_flags |= ERF_HAS_RSP_1;
                 x86_pmu.er_flags |= ERF_NO_HT_SHARING;
@@ -2123,7 +2132,10 @@ __init int intel_pmu_init(void)
                 x86_pmu.event_constraints = intel_ivb_event_constraints;
                 x86_pmu.pebs_constraints = intel_ivb_pebs_event_constraints;
                 x86_pmu.pebs_aliases = intel_pebs_aliases_snb;
-                x86_pmu.extra_regs = intel_snb_extra_regs;
+                if (boot_cpu_data.x86_model == 62)
+                        x86_pmu.extra_regs = intel_snbep_extra_regs;
+                else
+                        x86_pmu.extra_regs = intel_snb_extra_regs;
                 /* all extra regs are per-cpu when HT is on */
                 x86_pmu.er_flags |= ERF_HAS_RSP_1;
                 x86_pmu.er_flags |= ERF_NO_HT_SHARING;