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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 2014-03-14 16:00:41 +11:00 committed by Benjamin Herrenschmidt
parent 7b43c67950
commit 220a0c609a
1 changed files with 294 additions and 0 deletions
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294
arch/powerpc/perf/hv-gpci.c Normal file
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/*
* Hypervisor supplied "gpci" ("get performance counter info") performance
* counter support
*
* Author: Cody P Schafer <cody@linux.vnet.ibm.com>
* Copyright 2014 IBM Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#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 */
EVENT_DEFINE_RANGE_FORMAT(starting_index, 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 struct attribute *format_attrs[] = {
&format_attr_request.attr,
&format_attr_starting_index.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,
};
#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);
}
DEVICE_ATTR_RO(kernel_version);
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_group interface_group = {
.name = "interface",
.attrs = interface_attrs,
};
static const struct attribute_group *attr_groups[] = {
&format_group,
&interface_group,
NULL,
};
#define GPCI_MAX_DATA_BYTES \
(1024 - sizeof(struct hv_get_perf_counter_info_params))
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 {
struct hv_get_perf_counter_info_params params;
uint8_t bytes[GPCI_MAX_DATA_BYTES];
} __packed __aligned(sizeof(uint64_t)) arg = {
.params = {
.counter_request = cpu_to_be32(req),
.starting_index = cpu_to_be32(starting_index),
.secondary_index = cpu_to_be16(secondary_index),
.counter_info_version_in = version_in,
}
};
ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
virt_to_phys(&arg), sizeof(arg));
if (ret) {
pr_devel("hcall failed: 0x%lx\n", ret);
return ret;
}
/*
* we verify offset and length are within the zeroed buffer at event
* init.
*/
count = 0;
for (i = offset; i < offset + length; i++)
count |= arg.bytes[i] << (i - offset);
*value = count;
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;
}
/* unsupported modes and filters */
if (event->attr.exclude_user ||
event->attr.exclude_kernel ||
event->attr.exclude_hv ||
event->attr.exclude_idle ||
event->attr.exclude_host ||
event->attr.exclude_guest ||
is_sampling_event(event)) /* no sampling */
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) > GPCI_MAX_DATA_BYTES) {
pr_devel("request outside of buffer: %zu > %zu\n",
(size_t)event_get_offset(event) + length,
GPCI_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 int h_gpci_event_idx(struct perf_event *event)
{
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,
.event_idx = h_gpci_event_idx,
};
static int hv_gpci_init(void)
{
int r;
unsigned long hret;
struct hv_perf_caps caps;
if (!firmware_has_feature(FW_FEATURE_LPAR)) {
pr_info("not a virtualized system, not enabling\n");
return -ENODEV;
}
hret = hv_perf_caps_get(&caps);
if (hret) {
pr_info("could not obtain capabilities, error 0x%80lx, not enabling\n",
hret);
return -ENODEV;
}
r = perf_pmu_register(&h_gpci_pmu, h_gpci_pmu.name, -1);
if (r)
return r;
return 0;
}
device_initcall(hv_gpci_init);