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authorPeter Zijlstra <peterz@infradead.org>2014-02-05 20:48:51 +0100
committerIngo Molnar <mingo@kernel.org>2014-02-09 13:08:24 +0100
commite97df76377b8b3b1f7dfd5d6f8a1d5a31438b140 (patch)
treecd326431ed849d6778b31990970b8fcafac71a2c /arch
parent2737fce8bc8dea2852289df29b4f92e6a7fb7c91 (diff)
downloadblackbird-op-linux-e97df76377b8b3b1f7dfd5d6f8a1d5a31438b140.tar.gz
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perf/x86/intel/p6: Add userspace RDPMC quirk for PPro
PPro machines can die hard when PCE gets enabled due to a CPU erratum. The safe way it so disable it by default and keep it disabled. See erratum 26 in: http://download.intel.com/design/archives/processors/pro/docs/24268935.pdf Reported-and-Tested-by: Mark Davies <junk@eslaf.co.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Stephane Eranian <eranian@google.com> Cc: Vince Weaver <vince@deater.net> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140206170815.GW2936@laptop.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/perf_event.c6
-rw-r--r--arch/x86/kernel/cpu/perf_event.h1
-rw-r--r--arch/x86/kernel/cpu/perf_event_p6.c48
3 files changed, 39 insertions, 16 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index b88645191fe5..1246b853c4e0 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1521,6 +1521,8 @@ static int __init init_hw_perf_events(void)
pr_cont("%s PMU driver.\n", x86_pmu.name);
+ x86_pmu.attr_rdpmc = 1; /* enable userspace RDPMC usage by default */
+
for (quirk = x86_pmu.quirks; quirk; quirk = quirk->next)
quirk->func();
@@ -1534,7 +1536,6 @@ static int __init init_hw_perf_events(void)
__EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_counters) - 1,
0, x86_pmu.num_counters, 0, 0);
- x86_pmu.attr_rdpmc = 1; /* enable userspace RDPMC usage by default */
x86_pmu_format_group.attrs = x86_pmu.format_attrs;
if (x86_pmu.event_attrs)
@@ -1820,6 +1821,9 @@ static ssize_t set_attr_rdpmc(struct device *cdev,
if (ret)
return ret;
+ if (x86_pmu.attr_rdpmc_broken)
+ return -ENOTSUPP;
+
if (!!val != !!x86_pmu.attr_rdpmc) {
x86_pmu.attr_rdpmc = !!val;
smp_call_function(change_rdpmc, (void *)val, 1);
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index c1a861829d81..4972c244d0bc 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -409,6 +409,7 @@ struct x86_pmu {
/*
* sysfs attrs
*/
+ int attr_rdpmc_broken;
int attr_rdpmc;
struct attribute **format_attrs;
struct attribute **event_attrs;
diff --git a/arch/x86/kernel/cpu/perf_event_p6.c b/arch/x86/kernel/cpu/perf_event_p6.c
index b1e2fe115323..7c1a0c07b607 100644
--- a/arch/x86/kernel/cpu/perf_event_p6.c
+++ b/arch/x86/kernel/cpu/perf_event_p6.c
@@ -231,31 +231,49 @@ static __initconst const struct x86_pmu p6_pmu = {
};
+static __init void p6_pmu_rdpmc_quirk(void)
+{
+ if (boot_cpu_data.x86_mask < 9) {
+ /*
+ * PPro erratum 26; fixed in stepping 9 and above.
+ */
+ pr_warn("Userspace RDPMC support disabled due to a CPU erratum\n");
+ x86_pmu.attr_rdpmc_broken = 1;
+ x86_pmu.attr_rdpmc = 0;
+ }
+}
+
__init int p6_pmu_init(void)
{
+ x86_pmu = p6_pmu;
+
switch (boot_cpu_data.x86_model) {
- case 1:
- case 3: /* Pentium Pro */
- case 5:
- case 6: /* Pentium II */
- case 7:
- case 8:
- case 11: /* Pentium III */
- case 9:
- case 13:
- /* Pentium M */
+ case 1: /* Pentium Pro */
+ x86_add_quirk(p6_pmu_rdpmc_quirk);
+ break;
+
+ case 3: /* Pentium II - Klamath */
+ case 5: /* Pentium II - Deschutes */
+ case 6: /* Pentium II - Mendocino */
break;
+
+ case 7: /* Pentium III - Katmai */
+ case 8: /* Pentium III - Coppermine */
+ case 10: /* Pentium III Xeon */
+ case 11: /* Pentium III - Tualatin */
+ break;
+
+ case 9: /* Pentium M - Banias */
+ case 13: /* Pentium M - Dothan */
+ break;
+
default:
- pr_cont("unsupported p6 CPU model %d ",
- boot_cpu_data.x86_model);
+ pr_cont("unsupported p6 CPU model %d ", boot_cpu_data.x86_model);
return -ENODEV;
}
- x86_pmu = p6_pmu;
-
memcpy(hw_cache_event_ids, p6_hw_cache_event_ids,
sizeof(hw_cache_event_ids));
-
return 0;
}
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