powerpc/perf/hv-24x7: Display domain indices in sysfs

To help users determine domains, display the domain indices used by the
kernel in sysfs.

	$ cat /sys/bus/event_source/devices/hv_24x7/interface/domains
	1: Physical Chip
	2: Physical Core
	3: VCPU Home Core
	4: VCPU Home Chip
	5: VCPU Home Node
	6: VCPU Remote Node

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

2 files changed, 42 insertions, 0 deletions

diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index 77b958f213a0..36b29fd9295d 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -68,6 +68,24 @@ static bool is_physical_domain(unsigned domain)
         }
 }
 
+static const char *domain_name(unsigned domain)
+{
+        if (!domain_is_valid(domain))
+                return NULL;
+
+        switch (domain) {
+        case HV_PERF_DOMAIN_PHYS_CHIP:          return "Physical Chip";
+        case HV_PERF_DOMAIN_PHYS_CORE:          return "Physical Core";
+        case HV_PERF_DOMAIN_VCPU_HOME_CORE:     return "VCPU Home Core";
+        case HV_PERF_DOMAIN_VCPU_HOME_CHIP:     return "VCPU Home Chip";
+        case HV_PERF_DOMAIN_VCPU_HOME_NODE:     return "VCPU Home Node";
+        case HV_PERF_DOMAIN_VCPU_REMOTE_NODE:   return "VCPU Remote Node";
+        }
+
+        WARN_ON_ONCE(domain);
+        return NULL;
+}
+
 static bool catalog_entry_domain_is_valid(unsigned domain)
 {
         return is_physical_domain(domain);
@@ -969,6 +987,27 @@ e_free:
         return ret;
 }
 
+static ssize_t domains_show(struct device *dev, struct device_attribute *attr,
+                            char *page)
+{
+        int d, n, count = 0;
+        const char *str;
+
+        for (d = 0; d < HV_PERF_DOMAIN_MAX; d++) {
+                str = domain_name(d);
+                if (!str)
+                        continue;
+
+                n = sprintf(page, "%d: %s\n", d, str);
+                if (n < 0)
+                        break;
+
+                count += n;
+                page += n;
+        }
+        return count;
+}
+
 #define PAGE_0_ATTR(_name, _fmt, _expr)                         \
 static ssize_t _name##_show(struct device *dev,                 \
                             struct device_attribute *dev_attr,  \
@@ -997,6 +1036,7 @@ PAGE_0_ATTR(catalog_version, "%lld\n",
 PAGE_0_ATTR(catalog_len, "%lld\n",
                 (unsigned long long)be32_to_cpu(page_0->length) * 4096);
 static BIN_ATTR_RO(catalog, 0/* real length varies */);
+static DEVICE_ATTR_RO(domains);
 
 static struct bin_attribute *if_bin_attrs[] = {
         &bin_attr_catalog,
@@ -1006,6 +1046,7 @@ static struct bin_attribute *if_bin_attrs[] = {
 static struct attribute *if_attrs[] = {
         &dev_attr_catalog_len.attr,
         &dev_attr_catalog_version.attr,
+        &dev_attr_domains.attr,
         NULL,
 };
 
diff --git a/arch/powerpc/perf/hv-24x7.h b/arch/powerpc/perf/hv-24x7.h
index c57d67dc9f3f..791455e7f5cf 100644
--- a/arch/powerpc/perf/hv-24x7.h
+++ b/arch/powerpc/perf/hv-24x7.h
@@ -7,6 +7,7 @@ enum hv_perf_domains {
 #define DOMAIN(n, v, x, c) HV_PERF_DOMAIN_##n = v,
 #include "hv-24x7-domains.h"
 #undef DOMAIN
+        HV_PERF_DOMAIN_MAX,
 };
 
 struct hv_24x7_request {