powerpc/perf: Add support for the hv gpci (get performance counter info) interface
This provides a basic link between perf and hv_gpci. Notably, it does not yet support transactions and does not list any events (they can still be manually composed). Example usage via perf tool: perf stat -e 'hv_gpci/counter_info_version=3,offset=0,length=8,secondary_index=0,starting_index=0xffffffff,request=0x10/' -r 0 -C 0 -x ' ' sleep 0.1 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>
This commit is contained in:
Cody P Schafer
Benjamin Herrenschmidt
parent
7b43c67950
commit
220a0c609a
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@ -0,0 +1,294 @@
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/*
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* Hypervisor supplied "gpci" ("get performance counter info") performance
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* counter support
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*
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* Author: Cody P Schafer <cody@linux.vnet.ibm.com>
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* Copyright 2014 IBM Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#define pr_fmt(fmt) "hv-gpci: " fmt
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#include <linux/init.h>
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#include <linux/perf_event.h>
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#include <asm/firmware.h>
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#include <asm/hvcall.h>
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#include <asm/io.h>
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#include "hv-gpci.h"
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#include "hv-common.h"
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/*
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* Example usage:
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* perf stat -e 'hv_gpci/counter_info_version=3,offset=0,length=8,
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* secondary_index=0,starting_index=0xffffffff,request=0x10/' ...
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*/
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/* u32 */
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EVENT_DEFINE_RANGE_FORMAT(request, config, 0, 31);
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/* u32 */
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EVENT_DEFINE_RANGE_FORMAT(starting_index, config, 32, 63);
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/* u16 */
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EVENT_DEFINE_RANGE_FORMAT(secondary_index, config1, 0, 15);
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/* u8 */
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EVENT_DEFINE_RANGE_FORMAT(counter_info_version, config1, 16, 23);
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/* u8, bytes of data (1-8) */
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EVENT_DEFINE_RANGE_FORMAT(length, config1, 24, 31);
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/* u32, byte offset */
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EVENT_DEFINE_RANGE_FORMAT(offset, config1, 32, 63);
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static struct attribute *format_attrs[] = {
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&format_attr_request.attr,
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&format_attr_starting_index.attr,
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&format_attr_secondary_index.attr,
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&format_attr_counter_info_version.attr,
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&format_attr_offset.attr,
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&format_attr_length.attr,
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NULL,
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};
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static struct attribute_group format_group = {
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.name = "format",
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.attrs = format_attrs,
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};
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#define HV_CAPS_ATTR(_name, _format) \
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static ssize_t _name##_show(struct device *dev, \
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struct device_attribute *attr, \
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char *page) \
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{ \
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struct hv_perf_caps caps; \
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unsigned long hret = hv_perf_caps_get(&caps); \
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if (hret) \
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return -EIO; \
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\
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return sprintf(page, _format, caps._name); \
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} \
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static struct device_attribute hv_caps_attr_##_name = __ATTR_RO(_name)
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static ssize_t kernel_version_show(struct device *dev,
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struct device_attribute *attr,
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char *page)
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{
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return sprintf(page, "0x%x\n", COUNTER_INFO_VERSION_CURRENT);
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}
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DEVICE_ATTR_RO(kernel_version);
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HV_CAPS_ATTR(version, "0x%x\n");
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HV_CAPS_ATTR(ga, "%d\n");
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HV_CAPS_ATTR(expanded, "%d\n");
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HV_CAPS_ATTR(lab, "%d\n");
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HV_CAPS_ATTR(collect_privileged, "%d\n");
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static struct attribute *interface_attrs[] = {
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&dev_attr_kernel_version.attr,
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&hv_caps_attr_version.attr,
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&hv_caps_attr_ga.attr,
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&hv_caps_attr_expanded.attr,
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&hv_caps_attr_lab.attr,
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&hv_caps_attr_collect_privileged.attr,
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NULL,
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};
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static struct attribute_group interface_group = {
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.name = "interface",
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.attrs = interface_attrs,
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};
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static const struct attribute_group *attr_groups[] = {
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&format_group,
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&interface_group,
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NULL,
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};
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#define GPCI_MAX_DATA_BYTES \
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(1024 - sizeof(struct hv_get_perf_counter_info_params))
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static unsigned long single_gpci_request(u32 req, u32 starting_index,
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u16 secondary_index, u8 version_in, u32 offset, u8 length,
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u64 *value)
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{
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unsigned long ret;
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size_t i;
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u64 count;
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struct {
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struct hv_get_perf_counter_info_params params;
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uint8_t bytes[GPCI_MAX_DATA_BYTES];
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} __packed __aligned(sizeof(uint64_t)) arg = {
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.params = {
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.counter_request = cpu_to_be32(req),
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.starting_index = cpu_to_be32(starting_index),
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.secondary_index = cpu_to_be16(secondary_index),
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.counter_info_version_in = version_in,
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}
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};
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ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
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virt_to_phys(&arg), sizeof(arg));
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if (ret) {
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pr_devel("hcall failed: 0x%lx\n", ret);
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return ret;
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}
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/*
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* we verify offset and length are within the zeroed buffer at event
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* init.
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*/
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count = 0;
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for (i = offset; i < offset + length; i++)
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count |= arg.bytes[i] << (i - offset);
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*value = count;
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return ret;
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}
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static u64 h_gpci_get_value(struct perf_event *event)
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{
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u64 count;
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unsigned long ret = single_gpci_request(event_get_request(event),
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event_get_starting_index(event),
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event_get_secondary_index(event),
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event_get_counter_info_version(event),
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event_get_offset(event),
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event_get_length(event),
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&count);
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if (ret)
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return 0;
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return count;
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}
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static void h_gpci_event_update(struct perf_event *event)
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{
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s64 prev;
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u64 now = h_gpci_get_value(event);
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prev = local64_xchg(&event->hw.prev_count, now);
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local64_add(now - prev, &event->count);
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}
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static void h_gpci_event_start(struct perf_event *event, int flags)
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{
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local64_set(&event->hw.prev_count, h_gpci_get_value(event));
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}
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static void h_gpci_event_stop(struct perf_event *event, int flags)
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{
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h_gpci_event_update(event);
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}
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static int h_gpci_event_add(struct perf_event *event, int flags)
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{
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if (flags & PERF_EF_START)
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h_gpci_event_start(event, flags);
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return 0;
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}
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static int h_gpci_event_init(struct perf_event *event)
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{
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u64 count;
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u8 length;
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/* Not our event */
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if (event->attr.type != event->pmu->type)
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return -ENOENT;
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/* config2 is unused */
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if (event->attr.config2) {
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pr_devel("config2 set when reserved\n");
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return -EINVAL;
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}
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/* unsupported modes and filters */
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if (event->attr.exclude_user ||
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event->attr.exclude_kernel ||
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event->attr.exclude_hv ||
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event->attr.exclude_idle ||
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event->attr.exclude_host ||
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event->attr.exclude_guest ||
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is_sampling_event(event)) /* no sampling */
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return -EINVAL;
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/* no branch sampling */
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if (has_branch_stack(event))
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return -EOPNOTSUPP;
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length = event_get_length(event);
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if (length < 1 || length > 8) {
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pr_devel("length invalid\n");
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return -EINVAL;
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}
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/* last byte within the buffer? */
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if ((event_get_offset(event) + length) > GPCI_MAX_DATA_BYTES) {
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pr_devel("request outside of buffer: %zu > %zu\n",
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(size_t)event_get_offset(event) + length,
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GPCI_MAX_DATA_BYTES);
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return -EINVAL;
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}
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/* check if the request works... */
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if (single_gpci_request(event_get_request(event),
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event_get_starting_index(event),
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event_get_secondary_index(event),
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event_get_counter_info_version(event),
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event_get_offset(event),
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length,
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&count)) {
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pr_devel("gpci hcall failed\n");
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return -EINVAL;
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}
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return 0;
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}
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static int h_gpci_event_idx(struct perf_event *event)
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{
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return 0;
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}
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static struct pmu h_gpci_pmu = {
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.task_ctx_nr = perf_invalid_context,
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.name = "hv_gpci",
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.attr_groups = attr_groups,
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.event_init = h_gpci_event_init,
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.add = h_gpci_event_add,
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.del = h_gpci_event_stop,
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.start = h_gpci_event_start,
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.stop = h_gpci_event_stop,
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.read = h_gpci_event_update,
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.event_idx = h_gpci_event_idx,
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};
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static int hv_gpci_init(void)
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{
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int r;
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unsigned long hret;
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struct hv_perf_caps caps;
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if (!firmware_has_feature(FW_FEATURE_LPAR)) {
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pr_info("not a virtualized system, not enabling\n");
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return -ENODEV;
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}
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hret = hv_perf_caps_get(&caps);
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if (hret) {
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pr_info("could not obtain capabilities, error 0x%80lx, not enabling\n",
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hret);
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return -ENODEV;
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}
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r = perf_pmu_register(&h_gpci_pmu, h_gpci_pmu.name, -1);
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if (r)
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return r;
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return 0;
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}
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device_initcall(hv_gpci_init);
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