1 files changed, 394 insertions, 0 deletions
diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
new file mode 100644
index 000000000..28b770bbc
--- /dev/null
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -0,0 +1,394 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hypervisor supplied "gpci" ("get performance counter info") performance
+ * counter support
+ *
+ * Author: Cody P Schafer <cody@linux.vnet.ibm.com>
+ * Copyright 2014 IBM Corporation.
+ */
+
+#define pr_fmt(fmt) "hv-gpci: " fmt
+
+#include <linux/init.h>
+#include <linux/perf_event.h>
+#include <asm/firmware.h>
+#include <asm/hvcall.h>
+#include <asm/io.h>
+
+#include "hv-gpci.h"
+#include "hv-common.h"
+
+/*
+ * Example usage:
+ *  perf stat -e 'hv_gpci/counter_info_version=3,offset=0,length=8,
+ *		  secondary_index=0,starting_index=0xffffffff,request=0x10/' ...
+ */
+
+/* u32 */
+EVENT_DEFINE_RANGE_FORMAT(request, config, 0, 31);
+/* u32 */
+/*
+ * Note that starting_index, phys_processor_idx, sibling_part_id,
+ * hw_chip_id, partition_id all refer to the same bit range. They
+ * are basically aliases for the starting_index. The specific alias
+ * used depends on the event. See REQUEST_IDX_KIND in hv-gpci-requests.h
+ */
+EVENT_DEFINE_RANGE_FORMAT(starting_index, config, 32, 63);
+EVENT_DEFINE_RANGE_FORMAT_LITE(phys_processor_idx, config, 32, 63);
+EVENT_DEFINE_RANGE_FORMAT_LITE(sibling_part_id, config, 32, 63);
+EVENT_DEFINE_RANGE_FORMAT_LITE(hw_chip_id, config, 32, 63);
+EVENT_DEFINE_RANGE_FORMAT_LITE(partition_id, config, 32, 63);
+
+/* u16 */
+EVENT_DEFINE_RANGE_FORMAT(secondary_index, config1, 0, 15);
+/* u8 */
+EVENT_DEFINE_RANGE_FORMAT(counter_info_version, config1, 16, 23);
+/* u8, bytes of data (1-8) */
+EVENT_DEFINE_RANGE_FORMAT(length, config1, 24, 31);
+/* u32, byte offset */
+EVENT_DEFINE_RANGE_FORMAT(offset, config1, 32, 63);
+
+static cpumask_t hv_gpci_cpumask;
+
+static struct attribute *format_attrs[] = {
+	&format_attr_request.attr,
+	&format_attr_starting_index.attr,
+	&format_attr_phys_processor_idx.attr,
+	&format_attr_sibling_part_id.attr,
+	&format_attr_hw_chip_id.attr,
+	&format_attr_partition_id.attr,
+	&format_attr_secondary_index.attr,
+	&format_attr_counter_info_version.attr,
+
+	&format_attr_offset.attr,
+	&format_attr_length.attr,
+	NULL,
+};
+
+static struct attribute_group format_group = {
+	.name = "format",
+	.attrs = format_attrs,
+};
+
+static struct attribute_group event_group = {
+	.name  = "events",
+	/* .attrs is set in init */
+};
+
+#define HV_CAPS_ATTR(_name, _format)				\
+static ssize_t _name##_show(struct device *dev,			\
+			    struct device_attribute *attr,	\
+			    char *page)				\
+{								\
+	struct hv_perf_caps caps;				\
+	unsigned long hret = hv_perf_caps_get(&caps);		\
+	if (hret)						\
+		return -EIO;					\
+								\
+	return sprintf(page, _format, caps._name);		\
+}								\
+static struct device_attribute hv_caps_attr_##_name = __ATTR_RO(_name)
+
+static ssize_t kernel_version_show(struct device *dev,
+				   struct device_attribute *attr,
+				   char *page)
+{
+	return sprintf(page, "0x%x\n", COUNTER_INFO_VERSION_CURRENT);
+}
+
+static ssize_t cpumask_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	return cpumap_print_to_pagebuf(true, buf, &hv_gpci_cpumask);
+}
+
+static DEVICE_ATTR_RO(kernel_version);
+static DEVICE_ATTR_RO(cpumask);
+
+HV_CAPS_ATTR(version, "0x%x\n");
+HV_CAPS_ATTR(ga, "%d\n");
+HV_CAPS_ATTR(expanded, "%d\n");
+HV_CAPS_ATTR(lab, "%d\n");
+HV_CAPS_ATTR(collect_privileged, "%d\n");
+
+static struct attribute *interface_attrs[] = {
+	&dev_attr_kernel_version.attr,
+	&hv_caps_attr_version.attr,
+	&hv_caps_attr_ga.attr,
+	&hv_caps_attr_expanded.attr,
+	&hv_caps_attr_lab.attr,
+	&hv_caps_attr_collect_privileged.attr,
+	NULL,
+};
+
+static struct attribute *cpumask_attrs[] = {
+	&dev_attr_cpumask.attr,
+	NULL,
+};
+
+static struct attribute_group cpumask_attr_group = {
+	.attrs = cpumask_attrs,
+};
+
+static struct attribute_group interface_group = {
+	.name = "interface",
+	.attrs = interface_attrs,
+};
+
+static const struct attribute_group *attr_groups[] = {
+	&format_group,
+	&event_group,
+	&interface_group,
+	&cpumask_attr_group,
+	NULL,
+};
+
+static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
+
+static unsigned long single_gpci_request(u32 req, u32 starting_index,
+		u16 secondary_index, u8 version_in, u32 offset, u8 length,
+		u64 *value)
+{
+	unsigned long ret;
+	size_t i;
+	u64 count;
+	struct hv_gpci_request_buffer *arg;
+
+	arg = (void *)get_cpu_var(hv_gpci_reqb);
+	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+	arg->params.counter_request = cpu_to_be32(req);
+	arg->params.starting_index = cpu_to_be32(starting_index);
+	arg->params.secondary_index = cpu_to_be16(secondary_index);
+	arg->params.counter_info_version_in = version_in;
+
+	ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
+			virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
+	if (ret) {
+		pr_devel("hcall failed: 0x%lx\n", ret);
+		goto out;
+	}
+
+	/*
+	 * we verify offset and length are within the zeroed buffer at event
+	 * init.
+	 */
+	count = 0;
+	for (i = offset; i < offset + length; i++)
+		count |= (u64)(arg->bytes[i]) << ((length - 1 - (i - offset)) * 8);
+
+	*value = count;
+out:
+	put_cpu_var(hv_gpci_reqb);
+	return ret;
+}
+
+static u64 h_gpci_get_value(struct perf_event *event)
+{
+	u64 count;
+	unsigned long ret = single_gpci_request(event_get_request(event),
+					event_get_starting_index(event),
+					event_get_secondary_index(event),
+					event_get_counter_info_version(event),
+					event_get_offset(event),
+					event_get_length(event),
+					&count);
+	if (ret)
+		return 0;
+	return count;
+}
+
+static void h_gpci_event_update(struct perf_event *event)
+{
+	s64 prev;
+	u64 now = h_gpci_get_value(event);
+	prev = local64_xchg(&event->hw.prev_count, now);
+	local64_add(now - prev, &event->count);
+}
+
+static void h_gpci_event_start(struct perf_event *event, int flags)
+{
+	local64_set(&event->hw.prev_count, h_gpci_get_value(event));
+}
+
+static void h_gpci_event_stop(struct perf_event *event, int flags)
+{
+	h_gpci_event_update(event);
+}
+
+static int h_gpci_event_add(struct perf_event *event, int flags)
+{
+	if (flags & PERF_EF_START)
+		h_gpci_event_start(event, flags);
+
+	return 0;
+}
+
+static int h_gpci_event_init(struct perf_event *event)
+{
+	u64 count;
+	u8 length;
+
+	/* Not our event */
+	if (event->attr.type != event->pmu->type)
+		return -ENOENT;
+
+	/* config2 is unused */
+	if (event->attr.config2) {
+		pr_devel("config2 set when reserved\n");
+		return -EINVAL;
+	}
+
+	/* no branch sampling */
+	if (has_branch_stack(event))
+		return -EOPNOTSUPP;
+
+	length = event_get_length(event);
+	if (length < 1 || length > 8) {
+		pr_devel("length invalid\n");
+		return -EINVAL;
+	}
+
+	/* last byte within the buffer? */
+	if ((event_get_offset(event) + length) > HGPCI_MAX_DATA_BYTES) {
+		pr_devel("request outside of buffer: %zu > %zu\n",
+				(size_t)event_get_offset(event) + length,
+				HGPCI_MAX_DATA_BYTES);
+		return -EINVAL;
+	}
+
+	/* check if the request works... */
+	if (single_gpci_request(event_get_request(event),
+				event_get_starting_index(event),
+				event_get_secondary_index(event),
+				event_get_counter_info_version(event),
+				event_get_offset(event),
+				length,
+				&count)) {
+		pr_devel("gpci hcall failed\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct pmu h_gpci_pmu = {
+	.task_ctx_nr = perf_invalid_context,
+
+	.name = "hv_gpci",
+	.attr_groups = attr_groups,
+	.event_init  = h_gpci_event_init,
+	.add         = h_gpci_event_add,
+	.del         = h_gpci_event_stop,
+	.start       = h_gpci_event_start,
+	.stop        = h_gpci_event_stop,
+	.read        = h_gpci_event_update,
+	.capabilities = PERF_PMU_CAP_NO_EXCLUDE,
+};
+
+static int ppc_hv_gpci_cpu_online(unsigned int cpu)
+{
+	if (cpumask_empty(&hv_gpci_cpumask))
+		cpumask_set_cpu(cpu, &hv_gpci_cpumask);
+
+	return 0;
+}
+
+static int ppc_hv_gpci_cpu_offline(unsigned int cpu)
+{
+	int target;
+
+	/* Check if exiting cpu is used for collecting gpci events */
+	if (!cpumask_test_and_clear_cpu(cpu, &hv_gpci_cpumask))
+		return 0;
+
+	/* Find a new cpu to collect gpci events */
+	target = cpumask_last(cpu_active_mask);
+
+	if (target < 0 || target >= nr_cpu_ids) {
+		pr_err("hv_gpci: CPU hotplug init failed\n");
+		return -1;
+	}
+
+	/* Migrate gpci events to the new target */
+	cpumask_set_cpu(target, &hv_gpci_cpumask);
+	perf_pmu_migrate_context(&h_gpci_pmu, cpu, target);
+
+	return 0;
+}
+
+static int hv_gpci_cpu_hotplug_init(void)
+{
+	return cpuhp_setup_state(CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE,
+			  "perf/powerpc/hv_gcpi:online",
+			  ppc_hv_gpci_cpu_online,
+			  ppc_hv_gpci_cpu_offline);
+}
+
+static int hv_gpci_init(void)
+{
+	int r;
+	unsigned long hret;
+	struct hv_perf_caps caps;
+	struct hv_gpci_request_buffer *arg;
+
+	hv_gpci_assert_offsets_correct();
+
+	if (!firmware_has_feature(FW_FEATURE_LPAR)) {
+		pr_debug("not a virtualized system, not enabling\n");
+		return -ENODEV;
+	}
+
+	hret = hv_perf_caps_get(&caps);
+	if (hret) {
+		pr_debug("could not obtain capabilities, not enabling, rc=%ld\n",
+				hret);
+		return -ENODEV;
+	}
+
+	/* init cpuhotplug */
+	r = hv_gpci_cpu_hotplug_init();
+	if (r)
+		return r;
+
+	/* sampling not supported */
+	h_gpci_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
+
+	arg = (void *)get_cpu_var(hv_gpci_reqb);
+	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+	/*
+	 * hcall H_GET_PERF_COUNTER_INFO populates the output
+	 * counter_info_version value based on the system hypervisor.
+	 * Pass the counter request 0x10 corresponds to request type
+	 * 'Dispatch_timebase_by_processor', to get the supported
+	 * counter_info_version.
+	 */
+	arg->params.counter_request = cpu_to_be32(0x10);
+
+	r = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
+			virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
+	if (r) {
+		pr_devel("hcall failed, can't get supported counter_info_version: 0x%x\n", r);
+		arg->params.counter_info_version_out = 0x8;
+	}
+
+	/*
+	 * Use counter_info_version_out value to assign
+	 * required hv-gpci event list.
+	 */
+	if (arg->params.counter_info_version_out >= 0x8)
+		event_group.attrs = hv_gpci_event_attrs;
+	else
+		event_group.attrs = hv_gpci_event_attrs_v6;
+
+	put_cpu_var(hv_gpci_reqb);
+
+	r = perf_pmu_register(&h_gpci_pmu, h_gpci_pmu.name, -1);
+	if (r)
+		return r;
+
+	return 0;
+}
+
+device_initcall(hv_gpci_init);