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Subject[tip:perf/urgent] perf/x86/intel/uncore: Fix boot crash on SBOX PMU on Haswell-EP
Commit-ID:  68055915c1c22489f9658bd2b7391bb11b2cf4e4
Gitweb: http://git.kernel.org/tip/68055915c1c22489f9658bd2b7391bb11b2cf4e4
Author: Andi Kleen <ak@linux.intel.com>
AuthorDate: Mon, 3 Nov 2014 17:00:28 -0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Sun, 16 Nov 2014 09:53:36 +0100

perf/x86/intel/uncore: Fix boot crash on SBOX PMU on Haswell-EP

There were several reports that on some systems writing the SBOX0 PMU
initialization MSR would #GP at boot. This did not happen on all
systems -- my two test systems booted fine.

Writing the three initialization bits bit-by-bit seems to avoid the
problem. So add a special callback to do just that.

This replaces an earlier patch that disabled the SBOX.

Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Reported-and-Tested-by: Patrick Lu <patrick.lu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: http://lkml.kernel.org/r/1415062828-19759-4-git-send-email-andi@firstfloor.org
[ Fixed a whitespace error and added attribution tags that were left out inexplicably. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
.../x86/kernel/cpu/perf_event_intel_uncore_snbep.c | 33 ++++++++++++++++++++--
1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore_snbep.c b/arch/x86/kernel/cpu/perf_event_intel_uncore_snbep.c
index 0af1c93..f9ed429 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore_snbep.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore_snbep.c
@@ -486,14 +486,17 @@ static struct attribute_group snbep_uncore_qpi_format_group = {
.attrs = snbep_uncore_qpi_formats_attr,
};

-#define SNBEP_UNCORE_MSR_OPS_COMMON_INIT() \
- .init_box = snbep_uncore_msr_init_box, \
+#define __SNBEP_UNCORE_MSR_OPS_COMMON_INIT() \
.disable_box = snbep_uncore_msr_disable_box, \
.enable_box = snbep_uncore_msr_enable_box, \
.disable_event = snbep_uncore_msr_disable_event, \
.enable_event = snbep_uncore_msr_enable_event, \
.read_counter = uncore_msr_read_counter

+#define SNBEP_UNCORE_MSR_OPS_COMMON_INIT() \
+ __SNBEP_UNCORE_MSR_OPS_COMMON_INIT(), \
+ .init_box = snbep_uncore_msr_init_box \
+
static struct intel_uncore_ops snbep_uncore_msr_ops = {
SNBEP_UNCORE_MSR_OPS_COMMON_INIT(),
};
@@ -1919,6 +1922,30 @@ static struct intel_uncore_type hswep_uncore_cbox = {
.format_group = &hswep_uncore_cbox_format_group,
};

+/*
+ * Write SBOX Initialization register bit by bit to avoid spurious #GPs
+ */
+static void hswep_uncore_sbox_msr_init_box(struct intel_uncore_box *box)
+{
+ unsigned msr = uncore_msr_box_ctl(box);
+
+ if (msr) {
+ u64 init = SNBEP_PMON_BOX_CTL_INT;
+ u64 flags = 0;
+ int i;
+
+ for_each_set_bit(i, (unsigned long *)&init, 64) {
+ flags |= (1ULL << i);
+ wrmsrl(msr, flags);
+ }
+ }
+}
+
+static struct intel_uncore_ops hswep_uncore_sbox_msr_ops = {
+ __SNBEP_UNCORE_MSR_OPS_COMMON_INIT(),
+ .init_box = hswep_uncore_sbox_msr_init_box
+};
+
static struct attribute *hswep_uncore_sbox_formats_attr[] = {
&format_attr_event.attr,
&format_attr_umask.attr,
@@ -1944,7 +1971,7 @@ static struct intel_uncore_type hswep_uncore_sbox = {
.event_mask = HSWEP_S_MSR_PMON_RAW_EVENT_MASK,
.box_ctl = HSWEP_S0_MSR_PMON_BOX_CTL,
.msr_offset = HSWEP_SBOX_MSR_OFFSET,
- .ops = &snbep_uncore_msr_ops,
+ .ops = &hswep_uncore_sbox_msr_ops,
.format_group = &hswep_uncore_sbox_format_group,
};


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