Merge tag 'stable/for-linus-3.12-rc0-tag-two' of git://git.kernel.org/pub/scm/linux...

[firefly-linux-kernel-4.4.55.git] / arch / tile / kernel / sysfs.c

diff --git a/arch/tile/kernel/sysfs.c b/arch/tile/kernel/sysfs.c
index e25b0a89c18f8e7c63cc3391477f8cadb255f468..a3ed12f8f83bf2c894e3b6eedf8e250a9e7f8312 100644 (file)
--- a/arch/tile/kernel/sysfs.c
+++ b/arch/tile/kernel/sysfs.c
@@ -157,6 +157,67 @@ hvconfig_bin_read(struct file *filp, struct kobject *kobj,
        return count;
 }
 
+static ssize_t hv_stats_show(struct device *dev,
+                            struct device_attribute *attr,
+                            char *page)
+{
+       int cpu = dev->id;
+       long lotar = HV_XY_TO_LOTAR(cpu_x(cpu), cpu_y(cpu));
+
+       ssize_t n = hv_confstr(HV_CONFSTR_HV_STATS,
+                              (unsigned long)page, PAGE_SIZE - 1,
+                              lotar, 0);
+       n = n < 0 ? 0 : min(n, (ssize_t)PAGE_SIZE - 1);
+       page[n] = '\0';
+       return n;
+}
+
+static ssize_t hv_stats_store(struct device *dev,
+                             struct device_attribute *attr,
+                             const char *page,
+                             size_t count)
+{
+       int cpu = dev->id;
+       long lotar = HV_XY_TO_LOTAR(cpu_x(cpu), cpu_y(cpu));
+
+       ssize_t n = hv_confstr(HV_CONFSTR_HV_STATS, 0, 0, lotar, 1);
+       return n < 0 ? n : count;
+}
+
+static DEVICE_ATTR(hv_stats, 0644, hv_stats_show, hv_stats_store);
+
+static int hv_stats_device_add(struct device *dev, struct subsys_interface *sif)
+{
+       int err, cpu = dev->id;
+
+       if (!cpu_online(cpu))
+               return 0;
+
+       err = sysfs_create_file(&dev->kobj, &dev_attr_hv_stats.attr);
+
+       return err;
+}
+
+static int hv_stats_device_remove(struct device *dev,
+                                 struct subsys_interface *sif)
+{
+       int cpu = dev->id;
+
+       if (!cpu_online(cpu))
+               return 0;
+
+       sysfs_remove_file(&dev->kobj, &dev_attr_hv_stats.attr);
+       return 0;
+}
+
+
+static struct subsys_interface hv_stats_interface = {
+       .name                   = "hv_stats",
+       .subsys                 = &cpu_subsys,
+       .add_dev                = hv_stats_device_add,
+       .remove_dev             = hv_stats_device_remove,
+};
+
 static int __init create_sysfs_entries(void)
 {
        int err = 0;
@@ -188,6 +249,21 @@ static int __init create_sysfs_entries(void)
                err = sysfs_create_bin_file(hypervisor_kobj, &hvconfig_bin);
        }
 
+       if (!err) {
+               /*
+                * Don't bother adding the hv_stats files on each CPU if
+                * our hypervisor doesn't supply statistics.
+                */
+               int cpu = raw_smp_processor_id();
+               long lotar = HV_XY_TO_LOTAR(cpu_x(cpu), cpu_y(cpu));
+               char dummy;
+               ssize_t n = hv_confstr(HV_CONFSTR_HV_STATS,
+                                      (unsigned long) &dummy, 1,
+                                      lotar, 0);
+               if (n >= 0)
+                       err = subsys_interface_register(&hv_stats_interface);
+       }
+
        return err;
 }
 subsys_initcall(create_sysfs_entries);