/*
* Perf support for the Statistical Profiling Extension, introduced as
* part of ARMv8.2.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright (C) 2016 ARM Limited
*
* Author: Will Deacon <will.deacon@arm.com>
*/
#define PMUNAME "arm_spe"
#define DRVNAME PMUNAME "_pmu"
#define pr_fmt(fmt) DRVNAME ": " fmt
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/capability.h>
#include <linux/cpuhotplug.h>
#include <linux/cpumask.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/perf_event.h>
#include <linux/platform_device.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/vmalloc.h>
#include <asm/barrier.h>
#include <asm/cpufeature.h>
#include <asm/mmu.h>
#include <asm/sysreg.h>
#define ARM_SPE_BUF_PAD_BYTE 0
struct arm_spe_pmu_buf {
int nr_pages;
bool snapshot;
void *base;
};
struct arm_spe_pmu {
struct pmu pmu;
struct platform_device *pdev;
cpumask_t supported_cpus;
struct hlist_node hotplug_node;
int irq; /* PPI */
u16 min_period;
u16 counter_sz;
#define SPE_PMU_FEAT_FILT_EVT (1UL << 0)
#define SPE_PMU_FEAT_FILT_TYP (1UL << 1)
#define SPE_PMU_FEAT_FILT_LAT (1UL << 2)
#define SPE_PMU_FEAT_ARCH_INST (1UL << 3)
#define SPE_PMU_FEAT_LDS (1UL << 4)
#define SPE_PMU_FEAT_ERND (1UL << 5)
#define SPE_PMU_FEAT_DEV_PROBED (1UL << 63)
u64 features;
u16 max_record_sz;
u16 align;
struct perf_output_handle __percpu *handle;
};
#define to_spe_pmu(p) (container_of(p, struct arm_spe_pmu, pmu))
/* Convert a free-running index from perf into an SPE buffer offset */
#define PERF_IDX2OFF(idx, buf) ((idx) % ((buf)->nr_pages << PAGE_SHIFT))
/* Keep track of our dynamic hotplug state */
static enum cpuhp_state arm_spe_pmu_online;
enum arm_spe_pmu_buf_fault_action {
SPE_PMU_BUF_FAULT_ACT_SPURIOUS,
SPE_PMU_BUF_FAULT_ACT_FATAL,
SPE_PMU_BUF_FAULT_ACT_OK,
};
/* This sysfs gunk was really good fun to write. */
enum arm_spe_pmu_capabilities {
SPE_PMU_CAP_ARCH_INST = 0,
SPE_PMU_CAP_ERND,
SPE_PMU_CAP_FEAT_MAX,
SPE_PMU_CAP_CNT_SZ = SPE_PMU_CAP_FEAT_MAX,
SPE_PMU_CAP_MIN_IVAL,
};
static int arm_spe_pmu_feat_caps[SPE_PMU_CAP_FEAT_MAX] = {
[SPE_PMU_CAP_ARCH_INST] = SPE_PMU_FEAT_ARCH_INST,
[SPE_PMU_CAP_ERND] = SPE_PMU_FEAT_ERND,
};
static u32 arm_spe_pmu_cap_get(struct arm_spe_pmu *spe_pmu, int cap)
{
if (cap < SPE_PMU_CAP_FEAT_MAX)
return !!(spe_pmu->features & arm_spe_pmu_feat_caps[cap]);
switch (cap) {
case SPE_PMU_CAP_CNT_SZ:
return spe_pmu->counter_sz;
case SPE_PMU_CAP_MIN_IVAL:
return spe_pmu->min_period;
default:
WARN(1, "unknown cap %d\n", cap);
}
return 0;
}
static ssize_t arm_spe_pmu_cap_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
struct dev_ext_attribute *ea =
container_of(attr, struct dev_ext_attribute, attr);
int cap = (long)ea->var;
return snprintf(buf, PAGE_SIZE, "%u\n",
arm_spe_pmu_cap_get(spe_pmu, cap));
}
#define SPE_EXT_ATTR_ENTRY(_name, _func, _var) \
&((struct dev_ext_attribute[]) { \
{ __ATTR(_name, S_IRUGO, _func, NULL), (void *)_var } \
})[0].attr.attr
#define SPE_CAP_EXT_ATTR_ENTRY(_name, _var) \
SPE_EXT_ATTR_ENTRY(_name, arm_spe_pmu_cap_show, _var)
static struct attribute *arm_spe_pmu_cap_attr[] = {
SPE_CAP_EXT_ATTR_ENTRY(arch_inst, SPE_PMU_CAP_ARCH_INST),
SPE_CAP_EXT_ATTR_ENTRY(ernd, SPE_PMU_CAP_ERND),
SPE_CAP_EXT_ATTR_ENTRY(count_size, SPE_PMU_CAP_CNT_SZ),
SPE_CAP_EXT_ATTR_ENTRY(min_interval, SPE_PMU_CAP_MIN_IVAL),
NULL,
};
static struct attribute_group arm_spe_pmu_cap_group = {
.name = "caps",
.attrs = arm_spe_pmu_cap_attr,
};
/* User ABI */
#define ATTR_CFG_FLD_ts_enable_CFG config /* PMSCR_EL1.TS */
#define ATTR_CFG_FLD_ts_enable_LO 0
#define ATTR_CFG_FLD_ts_enable_HI 0
#define ATTR_CFG_FLD_pa_enable_CFG config /* PMSCR_EL1.PA */
#define ATTR_CFG_FLD_pa_enable_LO 1
#define ATTR_CFG_FLD_pa_enable_HI 1
#define ATTR_CFG_FLD_pct_enable_CFG config /* PMSCR_EL1.PCT */
#define ATTR_CFG_FLD_pct_enable_LO 2
#define ATTR_CFG_FLD_pct_enable_HI 2
#define ATTR_CFG_FLD_jitter_CFG config /* PMSIRR_EL1.RND */
#define ATTR_CFG_FLD_jitter_LO 16
#define ATTR_CFG_FLD_jitter_HI 16
#define ATTR_CFG_FLD_branch_filter_CFG config /* PMSFCR_EL1.B */
#define ATTR_CFG_FLD_branch_filter_LO 32
#define ATTR_CFG_FLD_branch_filter_HI 32
#define ATTR_CFG_FLD_load_filter_CFG config /* PMSFCR_EL1.LD */
#define ATTR_CFG_FLD_load_filter_LO 33
#define ATTR_CFG_FLD_load_filter_HI 33
#define ATTR_CFG_FLD_store_filter_CFG config /* PMSFCR_EL1.ST */
#define ATTR_CFG_FLD_store_filter_LO 34
#define ATTR_CFG_FLD_store_filter_HI 34
#define ATTR_CFG_FLD_event_filter_CFG config1 /* PMSEVFR_EL1 */
#define ATTR_CFG_FLD_event_filter_LO 0
#define ATTR_CFG_FLD_event_filter_HI 63
#define ATTR_CFG_FLD_min_latency_CFG config2 /* PMSLATFR_EL1.MINLAT */
#define ATTR_CFG_FLD_min_latency_LO 0
#define ATTR_CFG_FLD_min_latency_HI 11
/* Why does everything I do descend into this? */
#define __GEN_PMU_FORMAT_ATTR(cfg, lo, hi) \
(lo) == (hi) ? #cfg ":" #lo "\n" : #cfg ":" #lo "-" #hi
#define _GEN_PMU_FORMAT_ATTR(cfg, lo, hi) \
__GEN_PMU_FORMAT_ATTR(cfg, lo, hi)
#define GEN_PMU_FORMAT_ATTR(name) \
PMU_FORMAT_ATTR(name, \
_GEN_PMU_FORMAT_ATTR(ATTR_CFG_FLD_##name##_CFG, \
ATTR_CFG_FLD_##name##_LO, \
ATTR_CFG_FLD_##name##_HI))
#define _ATTR_CFG_GET_FLD(attr, cfg, lo, hi) \
((((attr)->cfg) >> lo) & GENMASK(hi - lo, 0))
#define ATTR_CFG_GET_FLD(attr, name) \
_ATTR_CFG_GET_FLD(attr, \
ATTR_CFG_FLD_##name##_CFG, \
ATTR_CFG_FLD_##name##_LO, \
ATTR_CFG_FLD_##name##_HI)
GEN_PMU_FORMAT_ATTR(ts_enable);
GEN_PMU_FORMAT_ATTR(pa_enable);
GEN_PMU_FORMAT_ATTR(pct_enable);
GEN_PMU_FORMAT_ATTR(jitter);
GEN_PMU_FORMAT_ATTR(branch_filter);
GEN_PMU_FORMAT_ATTR(load_filter);
GEN_PMU_FORMAT_ATTR(store_filter);
GEN_PMU_FORMAT_ATTR(event_filter);
GEN_PMU_FORMAT_ATTR(min_latency);
static struct attribute *arm_spe_pmu_formats_attr[] = {
&format_attr_ts_enable.attr,
&format_attr_pa_enable.attr,
&format_attr_pct_enable.attr,
&format_attr_jitter.attr,
&format_attr_branch_filter.attr,
&format_attr_load_filter.attr,
&format_attr_store_filter.attr,
&format_attr_event_filter.attr,
&format_attr_min_latency.attr,
NULL,
};
static struct attribute_group arm_spe_pmu_format_group = {
.name = "format",
.attrs = arm_spe_pmu_formats_attr,
};
static ssize_t arm_spe_pmu_get_attr_cpumask(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
return cpumap_print_to_pagebuf(true, buf, &spe_pmu->supported_cpus);
}
static DEVICE_ATTR(cpumask, S_IRUGO, arm_spe_pmu_get_attr_cpumask, NULL);
static struct attribute *arm_spe_pmu_attrs[] = {
&dev_attr_cpumask.attr,
NULL,
};
static struct attribute_group arm_spe_pmu_group = {
.attrs = arm_spe_pmu_attrs,
};
static const struct attribute_group *arm_spe_pmu_attr_groups[] = {
&arm_spe_pmu_group,
&arm_spe_pmu_cap_group,
&arm_spe_pmu_format_group,
NULL,
};
/* Convert between user ABI and register values */
static u64 arm_spe_event_to_pmscr(struct perf_event *event)
{
struct perf_event_attr *attr = &event->attr;
u64 reg = 0;
reg |= ATTR_CFG_GET_FLD(attr, ts_enable) << SYS_PMSCR_EL1_TS_SHIFT;
reg |= ATTR_CFG_GET_FLD(attr, pa_enable) << SYS_PMSCR_EL1_PA_SHIFT;
reg |= ATTR_CFG_GET_FLD(attr, pct_enable) << SYS_PMSCR_EL1_PCT_SHIFT;
if (!attr->exclude_user)
reg |= BIT(SYS_PMSCR_EL1_E0SPE_SHIFT);
if (!attr->exclude_kernel)
reg |= BIT(SYS_PMSCR_EL1_E1SPE_SHIFT);
if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && capable(CAP_SYS_ADMIN))
reg |= BIT(SYS_PMSCR_EL1_CX_SHIFT);
return reg;
}
static void arm_spe_event_sanitise_period(struct perf_event *event)
{
struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
u64 period = event->hw.sample_period;
u64 max_period = SYS_PMSIRR_EL1_INTERVAL_MASK
<< SYS_PMSIRR_EL1_INTERVAL_SHIFT;
if (period < spe_pmu->min_period)
period = spe_pmu->min_period;
else if (period > max_period)
period = max_period;
else
period &= max_period;
event->hw.sample_period = period;
}
static u64 arm_spe_event_to_pmsirr(struct perf_event *event)
{
struct perf_event_attr *attr = &event->attr;
u64 reg = 0;
arm_spe_event_sanitise_period(event);
reg |= ATTR_CFG_GET_FLD(attr, jitter) << SYS_PMSIRR_EL1_RND_SHIFT;
reg |= event->hw.sample_period;
return reg;
}
static u64 arm_spe_event_to_pmsfcr(struct perf_event *event)
{
struct perf_event_attr *attr = &event->attr;
u64 reg = 0;
reg |= ATTR_CFG_GET_FLD(attr, load_filter) << SYS_PMSFCR_EL1_LD_SHIFT;
reg |= ATTR_CFG_GET_FLD(attr, store_filter) << SYS_PMSFCR_EL1_ST_SHIFT;
reg |= ATTR_CFG_GET_FLD(attr, branch_filter) << SYS_PMSFCR_EL1_B_SHIFT;
if (reg)
reg |= BIT(SYS_PMSFCR_EL1_FT_SHIFT);
if (ATTR_CFG_GET_FLD(attr, event_filter))
reg |= BIT(SYS_PMSFCR_EL1_FE_SHIFT);
if (ATTR_CFG_GET_FLD(attr, min_latency))
reg |= BIT(SYS_PMSFCR_EL1_FL_SHIFT);
return reg;
}
static u64 arm_spe_event_to_pmsevfr(struct perf_event *event)
{
struct perf_event_attr *attr = &event->attr;
return ATTR_CFG_GET_FLD(attr, event_filter);
}
static u64 arm_spe_event_to_pmslatfr(struct perf_event *event)
{
struct perf_event_attr *attr = &event->attr;
return ATTR_CFG_GET_FLD(attr, min_latency)
<< SYS_PMSLATFR_EL1_MINLAT_SHIFT;
}
static void arm_spe_pmu_pad_buf(struct perf_output_handle *handle, int len)
{
struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
u64 head = PERF_IDX2OFF(handle->head, buf);
memset(buf->base + head, ARM_SPE_BUF_PAD_BYTE, len);
if (!buf->snapshot)
perf_aux_output_skip(handle, len);
}
static u64 arm_spe_pmu_next_snapshot_off(struct perf_output_handle *handle)
{
struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
u64 head = PERF_IDX2OFF(handle->head, buf);
u64 limit = buf->nr_pages * PAGE_SIZE;
/*
* The trace format isn't parseable in reverse, so clamp
* the limit to half of the buffer size in snapshot mode
* so that the worst case is half a buffer of records, as
* opposed to a single record.
*/
if (head < limit >> 1)
limit >>= 1;
/*
* If we're within max_record_sz of the limit, we must
* pad, move the head index and recompute the limit.
*/
if (limit - head < spe_pmu->max_record_sz) {
arm_spe_pmu_pad_buf(handle, limit - head);
handle->head = PERF_IDX2OFF(limit, buf);
limit = ((buf->nr_pages * PAGE_SIZE) >> 1) + handle->head;
}
return limit;
}
static u64 __arm_spe_pmu_next_off(struct perf_output_handle *handle)
{
struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
const u64 bufsize = buf->nr_pages * PAGE_SIZE;
u64 limit = bufsize;
u64 head, tail, wakeup;
/*
* The head can be misaligned for two reasons:
*
* 1. The hardware left PMBPTR pointing to the first byte after
* a record when generating a buffer management event.
*
* 2. We used perf_aux_output_skip to consume handle->size bytes
* and CIRC_SPACE was used to compute the size, which always
* leaves one entry free.
*
* Deal with this by padding to the next alignment boundary and
* moving the head index. If we run out of buffer space, we'll
* reduce handle->size to zero and end up reporting truncation.
*/
head = PERF_IDX2OFF(handle->head, buf);
if (!IS_ALIGNED(head, spe_pmu->align)) {
unsigned long delta = roundup(head, spe_pmu->align) - head;
delta = min(delta, handle->size);
arm_spe_pmu_pad_buf(handle, delta);
head = PERF_IDX2OFF(handle->head, buf);
}
/* If we've run out of free space, then nothing more to do */
if (!handle->size)
goto no_space;
/* Compute the tail and wakeup indices now that we've aligned head */
tail = PERF_IDX2OFF(handle->head + handle->size, buf);
wakeup = PERF_IDX2OFF(handle->wakeup, buf);
/*
* Avoid clobbering unconsumed data. We know we have space, so
* if we see head == tail we know that the buffer is empty. If
* head > tail, then there's nothing to clobber prior to
* wrapping.
*/
if (head < tail)
limit = round_down(tail, PAGE_SIZE);
/*
* Wakeup may be arbitrarily far into the future. If it's not in
* the current generation, either we'll wrap before hitting it,
* or it's in the past and has been handled already.
*
* If there's a wakeup before we wrap, arrange to be woken up by
* the page boundary following it. Keep the tail boundary if
* that's lower.
*/
if (handle->wakeup < (handle->head + handle->size) && head <= wakeup)
limit = min(limit, round_up(wakeup, PAGE_SIZE));
if (limit > head)
return limit;
arm_spe_pmu_pad_buf(handle, handle->size);
no_space:
perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
perf_aux_output_end(handle, 0);
return 0;
}
static u64 arm_spe_pmu_next_off(struct perf_output_handle *handle)
{
struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
u64 limit = __arm_spe_pmu_next_off(handle);
u64 head = PERF_IDX2OFF(handle->head, buf);
/*
* If the head has come too close to the end of the buffer,
* then pad to the end and recompute the limit.
*/
if (limit && (limit - head < spe_pmu->max_record_sz)) {
arm_spe_pmu_pad_buf(handle, limit - head);
limit = __arm_spe_pmu_next_off(handle);
}
return limit;
}
static void arm_spe_perf_aux_output_begin(struct perf_output_handle *handle,
struct perf_event *event)
{
u64 base, limit;
struct arm_spe_pmu_buf *buf;
/* Start a new aux session */
buf = perf_aux_output_begin(handle, event);
if (!buf) {
event->hw.state |= PERF_HES_STOPPED;
/*
* We still need to clear the limit pointer, since the
* profiler might only be disabled by virtue of a fault.
*/
limit = 0;
goto out_write_limit;
}
limit = buf->snapshot ? arm_spe_pmu_next_snapshot_off(handle)
: arm_spe_pmu_next_off(handle);
if (limit)
limit |= BIT(SYS_PMBLIMITR_EL1_E_SHIFT);
limit += (u64)buf->base;
base = (u64)buf->base + PERF_IDX2OFF(handle->head, buf);
write_sysreg_s(base, SYS_PMBPTR_EL1);
out_write_limit:
write_sysreg_s(limit, SYS_PMBLIMITR_EL1);
}
static void arm_spe_perf_aux_output_end(struct perf_output_handle *handle)
{
struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
u64 offset, size;
offset = read_sysreg_s(SYS_PMBPTR_EL1) - (u64)buf->base;
size = offset - PERF_IDX2OFF(handle->head, buf);
if (buf->snapshot)
handle->head = offset;
perf_aux_output_end(handle, size);
}
static void arm_spe_pmu_disable_and_drain_local(void)
{
/* Disable profiling at EL0 and EL1 */
write_sysreg_s(0, SYS_PMSCR_EL1);
isb();
/* Drain any buffered data */
psb_csync();
dsb(nsh);
/* Disable the profiling buffer */
write_sysreg_s(0, SYS_PMBLIMITR_EL1);
isb();
}
/* IRQ handling */
static enum arm_spe_pmu_buf_fault_action
arm_spe_pmu_buf_get_fault_act(struct perf_output_handle *handle)
{
const char *err_str;
u64 pmbsr;
enum arm_spe_pmu_buf_fault_action ret;
/*
* Ensure new profiling data is visible to the CPU and any external
* aborts have been resolved.
*/
psb_csync();
dsb(nsh);
/* Ensure hardware updates to PMBPTR_EL1 are visible */
isb();
/* Service required? */
pmbsr = read_sysreg_s(SYS_PMBSR_EL1);
if (!(pmbsr & BIT(SYS_PMBSR_EL1_S_SHIFT)))
return SPE_PMU_BUF_FAULT_ACT_SPURIOUS;
/*
* If we've lost data, disable profiling and also set the PARTIAL
* flag to indicate that the last record is corrupted.
*/
if (pmbsr & BIT(SYS_PMBSR_EL1_DL_SHIFT))
perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED |
PERF_AUX_FLAG_PARTIAL);
/* Report collisions to userspace so that it can up the period */
if (pmbsr & BIT(SYS_PMBSR_EL1_COLL_SHIFT))
perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION);
/* We only expect buffer management events */
switch (pmbsr & (SYS_PMBSR_EL1_EC_MASK << SYS_PMBSR_EL1_EC_SHIFT)) {
case SYS_PMBSR_EL1_EC_BUF:
/* Handled below */
break;
case SYS_PMBSR_EL1_EC_FAULT_S1:
case SYS_PMBSR_EL1_EC_FAULT_S2:
err_str = "Unexpected buffer fault";
goto out_err;
default:
err_str = "Unknown error code";
goto out_err;
}
/* Buffer management event */
switch (pmbsr &
(SYS_PMBSR_EL1_BUF_BSC_MASK << SYS_PMBSR_EL1_BUF_BSC_SHIFT)) {
case SYS_PMBSR_EL1_BUF_BSC_FULL:
ret = SPE_PMU_BUF_FAULT_ACT_OK;
goto out_stop;
default:
err_str = "Unknown buffer status code";
}
out_err:
pr_err_ratelimited("%s on CPU %d [PMBSR=0x%016llx, PMBPTR=0x%016llx, PMBLIMITR=0x%016llx]\n",
err_str, smp_processor_id(), pmbsr,
read_sysreg_s(SYS_PMBPTR_EL1),
read_sysreg_s(SYS_PMBLIMITR_EL1));
ret = SPE_PMU_BUF_FAULT_ACT_FATAL;
out_stop:
arm_spe_perf_aux_output_end(handle);
return ret;
}
static irqreturn_t arm_spe_pmu_irq_handler(int irq, void *dev)
{
struct perf_output_handle *handle = dev;
struct perf_event *event = handle->event;
enum arm_spe_pmu_buf_fault_action act;
if (!perf_get_aux(handle))
return IRQ_NONE;
act = arm_spe_pmu_buf_get_fault_act(handle);
if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
return IRQ_NONE;
/*
* Ensure perf callbacks have completed, which may disable the
* profiling buffer in response to a TRUNCATION flag.
*/
irq_work_run();
switch (act) {
case SPE_PMU_BUF_FAULT_ACT_FATAL:
/*
* If a fatal exception occurred then leaving the profiling
* buffer enabled is a recipe waiting to happen. Since
* fatal faults don't always imply truncation, make sure
* that the profiling buffer is disabled explicitly before
* clearing the syndrome register.
*/
arm_spe_pmu_disable_and_drain_local();
break;
case SPE_PMU_BUF_FAULT_ACT_OK:
/*
* We handled the fault (the buffer was full), so resume
* profiling as long as we didn't detect truncation.
* PMBPTR might be misaligned, but we'll burn that bridge
* when we get to it.
*/
if (!(handle->aux_flags & PERF_AUX_FLAG_TRUNCATED)) {
arm_spe_perf_aux_output_begin(handle, event);
isb();
}
break;
case SPE_PMU_BUF_FAULT_ACT_SPURIOUS:
/* We've seen you before, but GCC has the memory of a sieve. */
break;
}
/* The buffer pointers are now sane, so resume profiling. */
write_sysreg_s(0, SYS_PMBSR_EL1);
return IRQ_HANDLED;
}
/* Perf callbacks */
static int arm_spe_pmu_event_init(struct perf_event *event)
{
u64 reg;
struct perf_event_attr *attr = &event->attr;
struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
/* This is, of course, deeply driver-specific */
if (attr->type != event->pmu->type)
return -ENOENT;
if (event->cpu >= 0 &&
!cpumask_test_cpu(event->cpu, &spe_pmu->supported_cpus))
return -ENOENT;
if (arm_spe_event_to_pmsevfr(event) & SYS_PMSEVFR_EL1_RES0)
return -EOPNOTSUPP;
if (attr->exclude_idle)
return -EOPNOTSUPP;
/*
* Feedback-directed frequency throttling doesn't work when we
* have a buffer of samples. We'd need to manually count the
* samples in the buffer when it fills up and adjust the event
* count to reflect that. Instead, just force the user to specify
* a sample period.
*/
if (attr->freq)
return -EINVAL;
reg = arm_spe_event_to_pmsfcr(event);
if ((reg & BIT(SYS_PMSFCR_EL1_FE_SHIFT)) &&
!(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT))
return -EOPNOTSUPP;
if ((reg & BIT(SYS_PMSFCR_EL1_FT_SHIFT)) &&
!(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP))
return -EOPNOTSUPP;
if ((reg & BIT(SYS_PMSFCR_EL1_FL_SHIFT)) &&
!(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT))
return -EOPNOTSUPP;
reg = arm_spe_event_to_pmscr(event);
if (!capable(CAP_SYS_ADMIN) &&
(reg & (BIT(SYS_PMSCR_EL1_PA_SHIFT) |
BIT(SYS_PMSCR_EL1_CX_SHIFT) |
BIT(SYS_PMSCR_EL1_PCT_SHIFT))))
return -EACCES;
return 0;
}
static void arm_spe_pmu_start(struct perf_event *event, int flags)
{
u64 reg;
struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
struct hw_perf_event *hwc = &event->hw;
struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
hwc->state = 0;
arm_spe_perf_aux_output_begin(handle, event);
if (hwc->state)
return;
reg = arm_spe_event_to_pmsfcr(event);
write_sysreg_s(reg, SYS_PMSFCR_EL1);
reg = arm_spe_event_to_pmsevfr(event);
write_sysreg_s(reg, SYS_PMSEVFR_EL1);
reg = arm_spe_event_to_pmslatfr(event);
write_sysreg_s(reg, SYS_PMSLATFR_EL1);
if (flags & PERF_EF_RELOAD) {
reg = arm_spe_event_to_pmsirr(event);
write_sysreg_s(reg, SYS_PMSIRR_EL1);
isb();
reg = local64_read(&hwc->period_left);
write_sysreg_s(reg, SYS_PMSICR_EL1);
}
reg = arm_spe_event_to_pmscr(event);
isb();
write_sysreg_s(reg, SYS_PMSCR_EL1);
}
static void arm_spe_pmu_stop(struct perf_event *event, int flags)
{
struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
struct hw_perf_event *hwc = &event->hw;
struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
/* If we're already stopped, then nothing to do */
if (hwc->state & PERF_HES_STOPPED)
return;
/* Stop all trace generation */
arm_spe_pmu_disable_and_drain_local();
if (flags & PERF_EF_UPDATE) {
/*
* If there's a fault pending then ensure we contain it
* to this buffer, since we might be on the context-switch
* path.
*/
if (perf_get_aux(handle)) {
enum arm_spe_pmu_buf_fault_action act;
act = arm_spe_pmu_buf_get_fault_act(handle);
if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
arm_spe_perf_aux_output_end(handle);
else
write_sysreg_s(0, SYS_PMBSR_EL1);
}
/*
* This may also contain ECOUNT, but nobody else should
* be looking at period_left, since we forbid frequency
* based sampling.
*/
local64_set(&hwc->period_left, read_sysreg_s(SYS_PMSICR_EL1));
hwc->state |= PERF_HES_UPTODATE;
}
hwc->state |= PERF_HES_STOPPED;
}
static int arm_spe_pmu_add(struct perf_event *event, int flags)
{
int ret = 0;
struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
struct hw_perf_event *hwc = &event->hw;
int cpu = event->cpu == -1 ? smp_processor_id() : event->cpu;
if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
return -ENOENT;
hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
if (flags & PERF_EF_START) {
arm_spe_pmu_start(event, PERF_EF_RELOAD);
if (hwc->state & PERF_HES_STOPPED)
ret = -EINVAL;
}
return ret;
}
static void arm_spe_pmu_del(struct perf_event *event, int flags)
{
arm_spe_pmu_stop(event, PERF_EF_UPDATE);
}
static void arm_spe_pmu_read(struct perf_event *event)
{
}
static void *arm_spe_pmu_setup_aux(struct perf_event *event, void **pages,
int nr_pages, bool snapshot)
{
int i, cpu = event->cpu;
struct page **pglist;
struct arm_spe_pmu_buf *buf;
/* We need at least two pages for this to work. */
if (nr_pages < 2)
return NULL;
/*
* We require an even number of pages for snapshot mode, so that
* we can effectively treat the buffer as consisting of two equal
* parts and give userspace a fighting chance of getting some
* useful data out of it.
*/
if (!nr_pages || (snapshot && (nr_pages & 1)))
return NULL;
if (cpu == -1)
cpu = raw_smp_processor_id();
buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, cpu_to_node(cpu));
if (!buf)
return NULL;
pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL);
if (!pglist)
goto out_free_buf;
for (i = 0; i < nr_pages; ++i)
pglist[i] = virt_to_page(pages[i]);
buf->base = vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL);
if (!buf->base)
goto out_free_pglist;
buf->nr_pages = nr_pages;
buf->snapshot = snapshot;
kfree(pglist);
return buf;
out_free_pglist:
kfree(pglist);
out_free_buf:
kfree(buf);
return NULL;
}
static void arm_spe_pmu_free_aux(void *aux)
{
struct arm_spe_pmu_buf *buf = aux;
vunmap(buf->base);
kfree(buf);
}
/* Initialisation and teardown functions */
static int arm_spe_pmu_perf_init(struct arm_spe_pmu *spe_pmu)
{
static atomic_t pmu_idx = ATOMIC_INIT(-1);
int idx;
char *name;
struct device *dev = &spe_pmu->pdev->dev;
spe_pmu->pmu = (struct pmu) {
.module = THIS_MODULE,
.capabilities = PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE,
.attr_groups = arm_spe_pmu_attr_groups,
/*
* We hitch a ride on the software context here, so that
* we can support per-task profiling (which is not possible
* with the invalid context as it doesn't get sched callbacks).
* This requires that userspace either uses a dummy event for
* perf_event_open, since the aux buffer is not setup until
* a subsequent mmap, or creates the profiling event in a
* disabled state and explicitly PERF_EVENT_IOC_ENABLEs it
* once the buffer has been created.
*/
.task_ctx_nr = perf_sw_context,
.event_init = arm_spe_pmu_event_init,
.add = arm_spe_pmu_add,
.del = arm_spe_pmu_del,
.start = arm_spe_pmu_start,
.stop = arm_spe_pmu_stop,
.read = arm_spe_pmu_read,
.setup_aux = arm_spe_pmu_setup_aux,
.free_aux = arm_spe_pmu_free_aux,
};
idx = atomic_inc_return(&pmu_idx);
name = devm_kasprintf(dev, GFP_KERNEL, "%s_%d", PMUNAME, idx);
if (!name) {
dev_err(dev, "failed to allocate name for pmu %d\n", idx);
return -ENOMEM;
}
return perf_pmu_register(&spe_pmu->pmu, name, -1);
}
static void arm_spe_pmu_perf_destroy(struct arm_spe_pmu *spe_pmu)
{
perf_pmu_unregister(&spe_pmu->pmu);
}
static void __arm_spe_pmu_dev_probe(void *info)
{
int fld;
u64 reg;
struct arm_spe_pmu *spe_pmu = info;
struct device *dev = &spe_pmu->pdev->dev;
fld = cpuid_feature_extract_unsigned_field(read_cpuid(ID_AA64DFR0_EL1),
ID_AA64DFR0_PMSVER_SHIFT);
if (!fld) {
dev_err(dev,
"unsupported ID_AA64DFR0_EL1.PMSVer [%d] on CPU %d\n",
fld, smp_processor_id());
return;
}
/* Read PMBIDR first to determine whether or not we have access */
reg = read_sysreg_s(SYS_PMBIDR_EL1);
if (reg & BIT(SYS_PMBIDR_EL1_P_SHIFT)) {
dev_err(dev,
"profiling buffer owned by higher exception level\n");
return;
}
/* Minimum alignment. If it's out-of-range, then fail the probe */
fld = reg >> SYS_PMBIDR_EL1_ALIGN_SHIFT & SYS_PMBIDR_EL1_ALIGN_MASK;
spe_pmu->align = 1 << fld;
if (spe_pmu->align > SZ_2K) {
dev_err(dev, "unsupported PMBIDR.Align [%d] on CPU %d\n",
fld, smp_processor_id());
return;
}
/* It's now safe to read PMSIDR and figure out what we've got */
reg = read_sysreg_s(SYS_PMSIDR_EL1);
if (reg & BIT(SYS_PMSIDR_EL1_FE_SHIFT))
spe_pmu->features |= SPE_PMU_FEAT_FILT_EVT;
if (reg & BIT(SYS_PMSIDR_EL1_FT_SHIFT))
spe_pmu->features |= SPE_PMU_FEAT_FILT_TYP;
if (reg & BIT(SYS_PMSIDR_EL1_FL_SHIFT))
spe_pmu->features |= SPE_PMU_FEAT_FILT_LAT;
if (reg & BIT(SYS_PMSIDR_EL1_ARCHINST_SHIFT))
spe_pmu->features |= SPE_PMU_FEAT_ARCH_INST;
if (reg & BIT(SYS_PMSIDR_EL1_LDS_SHIFT))
spe_pmu->features |= SPE_PMU_FEAT_LDS;
if (reg & BIT(SYS_PMSIDR_EL1_ERND_SHIFT))
spe_pmu->features |= SPE_PMU_FEAT_ERND;
/* This field has a spaced out encoding, so just use a look-up */
fld = reg >> SYS_PMSIDR_EL1_INTERVAL_SHIFT & SYS_PMSIDR_EL1_INTERVAL_MASK;
switch (fld) {
case 0:
spe_pmu->min_period = 256;
break;
case 2:
spe_pmu->min_period = 512;
break;
case 3:
spe_pmu->min_period = 768;
break;
case 4:
spe_pmu->min_period = 1024;
break;
case 5:
spe_pmu->min_period = 1536;
break;
case 6:
spe_pmu->min_period = 2048;
break;
case 7:
spe_pmu->min_period = 3072;
break;
default:
dev_warn(dev, "unknown PMSIDR_EL1.Interval [%d]; assuming 8\n",
fld);
/* Fallthrough */
case 8:
spe_pmu->min_period = 4096;
}
/* Maximum record size. If it's out-of-range, then fail the probe */
fld = reg >> SYS_PMSIDR_EL1_MAXSIZE_SHIFT & SYS_PMSIDR_EL1_MAXSIZE_MASK;
spe_pmu->max_record_sz = 1 << fld;
if (spe_pmu->max_record_sz > SZ_2K || spe_pmu->max_record_sz < 16) {
dev_err(dev, "unsupported PMSIDR_EL1.MaxSize [%d] on CPU %d\n",
fld, smp_processor_id());
return;
}
fld = reg >> SYS_PMSIDR_EL1_COUNTSIZE_SHIFT & SYS_PMSIDR_EL1_COUNTSIZE_MASK;
switch (fld) {
default:
dev_warn(dev, "unknown PMSIDR_EL1.CountSize [%d]; assuming 2\n",
fld);
/* Fallthrough */
case 2:
spe_pmu->counter_sz = 12;
}
dev_info(dev,
"probed for CPUs %*pbl [max_record_sz %u, align %u, features 0x%llx]\n",
cpumask_pr_args(&spe_pmu->supported_cpus),
spe_pmu->max_record_sz, spe_pmu->align, spe_pmu->features);
spe_pmu->features |= SPE_PMU_FEAT_DEV_PROBED;
return;
}
static void __arm_spe_pmu_reset_local(void)
{
/*
* This is probably overkill, as we have no idea where we're
* draining any buffered data to...
*/
arm_spe_pmu_disable_and_drain_local();
/* Reset the buffer base pointer */
write_sysreg_s(0, SYS_PMBPTR_EL1);
isb();
/* Clear any pending management interrupts */
write_sysreg_s(0, SYS_PMBSR_EL1);
isb();
}
static void __arm_spe_pmu_setup_one(void *info)
{
struct arm_spe_pmu *spe_pmu = info;
__arm_spe_pmu_reset_local();
enable_percpu_irq(spe_pmu->irq, IRQ_TYPE_NONE);
}
static void __arm_spe_pmu_stop_one(void *info)
{
struct arm_spe_pmu *spe_pmu = info;
disable_percpu_irq(spe_pmu->irq);
__arm_spe_pmu_reset_local();
}
static int arm_spe_pmu_cpu_startup(unsigned int cpu, struct hlist_node *node)
{
struct arm_spe_pmu *spe_pmu;
spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
return 0;
__arm_spe_pmu_setup_one(spe_pmu);
return 0;
}
static int arm_spe_pmu_cpu_teardown(unsigned int cpu, struct hlist_node *node)
{
struct arm_spe_pmu *spe_pmu;
spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
return 0;
__arm_spe_pmu_stop_one(spe_pmu);
return 0;
}
static int arm_spe_pmu_dev_init(struct arm_spe_pmu *spe_pmu)
{
int ret;
cpumask_t *mask = &spe_pmu->supported_cpus;
/* Make sure we probe the hardware on a relevant CPU */
ret = smp_call_function_any(mask, __arm_spe_pmu_dev_probe, spe_pmu, 1);
if (ret || !(spe_pmu->features & SPE_PMU_FEAT_DEV_PROBED))
return -ENXIO;
/* Request our PPIs (note that the IRQ is still disabled) */
ret = request_percpu_irq(spe_pmu->irq, arm_spe_pmu_irq_handler, DRVNAME,
spe_pmu->handle);
if (ret)
return ret;
/*
* Register our hotplug notifier now so we don't miss any events.
* This will enable the IRQ for any supported CPUs that are already
* up.
*/
ret = cpuhp_state_add_instance(arm_spe_pmu_online,
&spe_pmu->hotplug_node);
if (ret)
free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
return ret;
}
static void arm_spe_pmu_dev_teardown(struct arm_spe_pmu *spe_pmu)
{
cpuhp_state_remove_instance(arm_spe_pmu_online, &spe_pmu->hotplug_node);
free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
}
/* Driver and device probing */
static int arm_spe_pmu_irq_probe(struct arm_spe_pmu *spe_pmu)
{
struct platform_device *pdev = spe_pmu->pdev;
int irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "failed to get IRQ (%d)\n", irq);
return -ENXIO;
}
if (!irq_is_percpu(irq)) {
dev_err(&pdev->dev, "expected PPI but got SPI (%d)\n", irq);
return -EINVAL;
}
if (irq_get_percpu_devid_partition(irq, &spe_pmu->supported_cpus)) {
dev_err(&pdev->dev, "failed to get PPI partition (%d)\n", irq);
return -EINVAL;
}
spe_pmu->irq = irq;
return 0;
}
static const struct of_device_id arm_spe_pmu_of_match[] = {
{ .compatible = "arm,statistical-profiling-extension-v1", .data = (void *)1 },
{ /* Sentinel */ },
};
MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match);
static int arm_spe_pmu_device_dt_probe(struct platform_device *pdev)
{
int ret;
struct arm_spe_pmu *spe_pmu;
struct device *dev = &pdev->dev;
/*
* If kernelspace is unmapped when running at EL0, then the SPE
* buffer will fault and prematurely terminate the AUX session.
*/
if (arm64_kernel_unmapped_at_el0()) {
dev_warn_once(dev, "profiling buffer inaccessible. Try passing \"kpti=off\" on the kernel command line\n");
return -EPERM;
}
spe_pmu = devm_kzalloc(dev, sizeof(*spe_pmu), GFP_KERNEL);
if (!spe_pmu) {
dev_err(dev, "failed to allocate spe_pmu\n");
return -ENOMEM;
}
spe_pmu->handle = alloc_percpu(typeof(*spe_pmu->handle));
if (!spe_pmu->handle)
return -ENOMEM;
spe_pmu->pdev = pdev;
platform_set_drvdata(pdev, spe_pmu);
ret = arm_spe_pmu_irq_probe(spe_pmu);
if (ret)
goto out_free_handle;
ret = arm_spe_pmu_dev_init(spe_pmu);
if (ret)
goto out_free_handle;
ret = arm_spe_pmu_perf_init(spe_pmu);
if (ret)
goto out_teardown_dev;
return 0;
out_teardown_dev:
arm_spe_pmu_dev_teardown(spe_pmu);
out_free_handle:
free_percpu(spe_pmu->handle);
return ret;
}
static int arm_spe_pmu_device_remove(struct platform_device *pdev)
{
struct arm_spe_pmu *spe_pmu = platform_get_drvdata(pdev);
arm_spe_pmu_perf_destroy(spe_pmu);
arm_spe_pmu_dev_teardown(spe_pmu);
free_percpu(spe_pmu->handle);
return 0;
}
static struct platform_driver arm_spe_pmu_driver = {
.driver = {
.name = DRVNAME,
.of_match_table = of_match_ptr(arm_spe_pmu_of_match),
},
.probe = arm_spe_pmu_device_dt_probe,
.remove = arm_spe_pmu_device_remove,
};
static int __init arm_spe_pmu_init(void)
{
int ret;
ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, DRVNAME,
arm_spe_pmu_cpu_startup,
arm_spe_pmu_cpu_teardown);
if (ret < 0)
return ret;
arm_spe_pmu_online = ret;
ret = platform_driver_register(&arm_spe_pmu_driver);
if (ret)
cpuhp_remove_multi_state(arm_spe_pmu_online);
return ret;
}
static void __exit arm_spe_pmu_exit(void)
{
platform_driver_unregister(&arm_spe_pmu_driver);
cpuhp_remove_multi_state(arm_spe_pmu_online);
}
module_init(arm_spe_pmu_init);
module_exit(arm_spe_pmu_exit);
MODULE_DESCRIPTION("Perf driver for the ARMv8.2 Statistical Profiling Extension");
MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
MODULE_LICENSE("GPL v2");
