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// 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 = hv_gpci_event_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);
}
static 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,
&event_group,
&interface_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 |= arg->bytes[i] << (i - offset);
*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;
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;
r = perf_pmu_register(&h_gpci_pmu, h_gpci_pmu.name, -1);
if (r)
return r;
return 0;
}
device_initcall(hv_gpci_init);
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