powerpc/perf: Add a shared interface to get gpci version and capabilities

This exposes a simple way to grab the firmware provided
collect_priveliged, ga, expanded, and lab capability bits. All of these
bits come in from the same gpci request, so we've exposed all of them.

Only the collect_priveliged bit is really used by the hv-gpci/hv-24x7
code, the other bits are simply exposed in sysfs to inform the user.

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 39 insertions, 0 deletions

diff --git a/arch/powerpc/perf/hv-common.c b/arch/powerpc/perf/hv-common.c
new file mode 100644
index 000000000000..47e02b366f58
--- /dev/null
+++ b/arch/powerpc/perf/hv-common.c
@@ -0,0 +1,39 @@
+#include <asm/io.h>
+#include <asm/hvcall.h>
+
+#include "hv-gpci.h"
+#include "hv-common.h"
+
+unsigned long hv_perf_caps_get(struct hv_perf_caps *caps)
+{
+        unsigned long r;
+        struct p {
+                struct hv_get_perf_counter_info_params params;
+                struct cv_system_performance_capabilities caps;
+        } __packed __aligned(sizeof(uint64_t));
+
+        struct p arg = {
+                .params = {
+                        .counter_request = cpu_to_be32(
+                                        CIR_SYSTEM_PERFORMANCE_CAPABILITIES),
+                        .starting_index = cpu_to_be32(-1),
+                        .counter_info_version_in = 0,
+                }
+        };
+
+        r = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
+                               virt_to_phys(&arg), sizeof(arg));
+
+        if (r)
+                return r;
+
+        pr_devel("capability_mask: 0x%x\n", arg.caps.capability_mask);
+
+        caps->version = arg.params.counter_info_version_out;
+        caps->collect_privileged = !!arg.caps.perf_collect_privileged;
+        caps->ga = !!(arg.caps.capability_mask & CV_CM_GA);
+        caps->expanded = !!(arg.caps.capability_mask & CV_CM_EXPANDED);
+        caps->lab = !!(arg.caps.capability_mask & CV_CM_LAB);
+
+        return r;
+}