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-rw-r--r--cpufreq-powernow-k8-Initialize-per-cpu-data-structures-properly.patch138
1 files changed, 138 insertions, 0 deletions
diff --git a/cpufreq-powernow-k8-Initialize-per-cpu-data-structures-properly.patch b/cpufreq-powernow-k8-Initialize-per-cpu-data-structures-properly.patch
new file mode 100644
index 000000000..70a553d2c
--- /dev/null
+++ b/cpufreq-powernow-k8-Initialize-per-cpu-data-structures-properly.patch
@@ -0,0 +1,138 @@
+Bugzilla: 1054408
+Upstream-status: Queued for 3.14 and CC'd to stable
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+From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
+Subject: [PATCH] cpufreq,
+ powernow-k8: Initialize per-cpu data-structures properly
+To: pierre-list@ossman.eu, rjw@rjwysocki.net
+Cc: viresh.kumar@linaro.org, linux-pm@vger.kernel.org,
+ linux-kernel@vger.kernel.org,
+ "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
+Date: Mon, 17 Feb 2014 16:18:21 +0530
+Message-ID: <20140217104821.21147.71463.stgit@srivatsabhat.in.ibm.com>
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+
+The powernow-k8 driver maintains a per-cpu data-structure called powernow_data
+that is used to perform the frequency transitions. It initializes this data-
+structure only for the policy->cpu. So, accesses to this data-structure by
+other CPUs results in various problems because they would have been
+uninitialized.
+
+Specifically, if a cpu (!= policy->cpu) invokes the drivers' ->get() function,
+it returns 0 as the KHz value, since its per-cpu memory doesn't point to
+anything valid. This causes problems during suspend/resume since
+cpufreq_update_policy() tries to enforce this (0 KHz) as the current frequency
+of the CPU, and this madness gets propagated to adjust_jiffies() as well.
+Eventually, lots of things start breaking down, including the r8169 ethernet
+card, in one particularly interesting case reported by Pierre Ossman.
+
+https://bugzilla.kernel.org/show_bug.cgi?id=70311
+
+Fix this by initializing the per-cpu data-structures of _all_ the CPUs
+in the policy appropriately.
+
+Cc: stable@vger.kernel.org
+Reported-by: Pierre Ossman <pierre@ossman.eu>
+Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
+---
+
+ drivers/cpufreq/powernow-k8.c | 10 +++++++---
+ 1 file changed, 7 insertions(+), 3 deletions(-)
+
+diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
+index e10b646..6684e03 100644
+--- a/drivers/cpufreq/powernow-k8.c
++++ b/drivers/cpufreq/powernow-k8.c
+@@ -1076,7 +1076,7 @@ static int powernowk8_cpu_init(struct cpufreq_policy *pol)
+ {
+ struct powernow_k8_data *data;
+ struct init_on_cpu init_on_cpu;
+- int rc;
++ int rc, cpu;
+
+ smp_call_function_single(pol->cpu, check_supported_cpu, &rc, 1);
+ if (rc)
+@@ -1140,7 +1140,9 @@ static int powernowk8_cpu_init(struct cpufreq_policy *pol)
+ pr_debug("cpu_init done, current fid 0x%x, vid 0x%x\n",
+ data->currfid, data->currvid);
+
+- per_cpu(powernow_data, pol->cpu) = data;
++ /* Point all the CPUs in this policy to the same data */
++ for_each_cpu(cpu, pol->cpus)
++ per_cpu(powernow_data, cpu) = data;
+
+ return 0;
+
+@@ -1155,6 +1157,7 @@ err_out:
+ static int powernowk8_cpu_exit(struct cpufreq_policy *pol)
+ {
+ struct powernow_k8_data *data = per_cpu(powernow_data, pol->cpu);
++ int cpu;
+
+ if (!data)
+ return -EINVAL;
+@@ -1165,7 +1168,8 @@ static int powernowk8_cpu_exit(struct cpufreq_policy *pol)
+
+ kfree(data->powernow_table);
+ kfree(data);
+- per_cpu(powernow_data, pol->cpu) = NULL;
++ for_each_cpu(cpu, pol->cpus)
++ per_cpu(powernow_data, cpu) = NULL;
+
+ return 0;
+ }
+
+--
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