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Message-ID: <20170603040354.3580555-2-ast@fb.com>
Date: Fri, 2 Jun 2017 21:03:52 -0700
From: Alexei Starovoitov <ast@...com>
To: "David S . Miller" <davem@...emloft.net>
CC: Peter Zijlstra <peterz@...radead.org>,
Brendan Gregg <bgregg@...flix.com>,
Daniel Borkmann <daniel@...earbox.net>,
Teng Qin <qinteng@...com>, <netdev@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <kernel-team@...com>
Subject: [PATCH v4 net-next 1/3] perf, bpf: Add BPF support to all perf_event types
Allow BPF_PROG_TYPE_PERF_EVENT program types to attach to all
perf_event types, including HW_CACHE, RAW, and dynamic pmu events.
Only tracepoint/kprobe events are treated differently which require
BPF_PROG_TYPE_TRACEPOINT/BPF_PROG_TYPE_KPROBE program types accordingly.
Also add support for reading all event counters using
bpf_perf_event_read() helper.
Signed-off-by: Alexei Starovoitov <ast@...nel.org>
---
include/linux/perf_event.h | 7 +++++--
kernel/bpf/arraymap.c | 28 +++++++--------------------
kernel/events/core.c | 47 +++++++++++++++++++++++++++-------------------
kernel/trace/bpf_trace.c | 21 ++++++++-------------
4 files changed, 48 insertions(+), 55 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 24a635887f28..8fc5f0fada5e 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -896,7 +896,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr,
void *context);
extern void perf_pmu_migrate_context(struct pmu *pmu,
int src_cpu, int dst_cpu);
-extern u64 perf_event_read_local(struct perf_event *event);
+int perf_event_read_local(struct perf_event *event, u64 *value);
extern u64 perf_event_read_value(struct perf_event *event,
u64 *enabled, u64 *running);
@@ -1301,7 +1301,10 @@ static inline const struct perf_event_attr *perf_event_attrs(struct perf_event *
{
return ERR_PTR(-EINVAL);
}
-static inline u64 perf_event_read_local(struct perf_event *event) { return -EINVAL; }
+static inline int perf_event_read_local(struct perf_event *event, u64 *value)
+{
+ return -EINVAL;
+}
static inline void perf_event_print_debug(void) { }
static inline int perf_event_task_disable(void) { return -EINVAL; }
static inline int perf_event_task_enable(void) { return -EINVAL; }
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 172dc8ee0e3b..ecb43542246e 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -452,38 +452,24 @@ static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
struct file *map_file, int fd)
{
- const struct perf_event_attr *attr;
struct bpf_event_entry *ee;
struct perf_event *event;
struct file *perf_file;
+ u64 value;
perf_file = perf_event_get(fd);
if (IS_ERR(perf_file))
return perf_file;
+ ee = ERR_PTR(-EOPNOTSUPP);
event = perf_file->private_data;
- ee = ERR_PTR(-EINVAL);
-
- attr = perf_event_attrs(event);
- if (IS_ERR(attr) || attr->inherit)
+ if (perf_event_read_local(event, &value) == -EOPNOTSUPP)
goto err_out;
- switch (attr->type) {
- case PERF_TYPE_SOFTWARE:
- if (attr->config != PERF_COUNT_SW_BPF_OUTPUT)
- goto err_out;
- /* fall-through */
- case PERF_TYPE_RAW:
- case PERF_TYPE_HARDWARE:
- ee = bpf_event_entry_gen(perf_file, map_file);
- if (ee)
- return ee;
- ee = ERR_PTR(-ENOMEM);
- /* fall-through */
- default:
- break;
- }
-
+ ee = bpf_event_entry_gen(perf_file, map_file);
+ if (ee)
+ return ee;
+ ee = ERR_PTR(-ENOMEM);
err_out:
fput(perf_file);
return ee;
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 6e75a5c9412d..51e40e4876c0 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3636,10 +3636,10 @@ static inline u64 perf_event_count(struct perf_event *event)
* will not be local and we cannot read them atomically
* - must not have a pmu::count method
*/
-u64 perf_event_read_local(struct perf_event *event)
+int perf_event_read_local(struct perf_event *event, u64 *value)
{
unsigned long flags;
- u64 val;
+ int ret = 0;
/*
* Disabling interrupts avoids all counter scheduling (context
@@ -3647,25 +3647,37 @@ u64 perf_event_read_local(struct perf_event *event)
*/
local_irq_save(flags);
- /* If this is a per-task event, it must be for current */
- WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
- event->hw.target != current);
-
- /* If this is a per-CPU event, it must be for this CPU */
- WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
- event->cpu != smp_processor_id());
-
/*
* It must not be an event with inherit set, we cannot read
* all child counters from atomic context.
*/
- WARN_ON_ONCE(event->attr.inherit);
+ if (event->attr.inherit) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
/*
* It must not have a pmu::count method, those are not
* NMI safe.
*/
- WARN_ON_ONCE(event->pmu->count);
+ if (event->pmu->count) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+
+ /* If this is a per-task event, it must be for current */
+ if ((event->attach_state & PERF_ATTACH_TASK) &&
+ event->hw.target != current) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* If this is a per-CPU event, it must be for this CPU */
+ if (!(event->attach_state & PERF_ATTACH_TASK) &&
+ event->cpu != smp_processor_id()) {
+ ret = -EINVAL;
+ goto out;
+ }
/*
* If the event is currently on this CPU, its either a per-task event,
@@ -3675,10 +3687,11 @@ u64 perf_event_read_local(struct perf_event *event)
if (event->oncpu == smp_processor_id())
event->pmu->read(event);
- val = local64_read(&event->count);
+ *value = local64_read(&event->count);
+out:
local_irq_restore(flags);
- return val;
+ return ret;
}
static int perf_event_read(struct perf_event *event, bool group)
@@ -8037,12 +8050,8 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
bool is_kprobe, is_tracepoint;
struct bpf_prog *prog;
- if (event->attr.type == PERF_TYPE_HARDWARE ||
- event->attr.type == PERF_TYPE_SOFTWARE)
- return perf_event_set_bpf_handler(event, prog_fd);
-
if (event->attr.type != PERF_TYPE_TRACEPOINT)
- return -EINVAL;
+ return perf_event_set_bpf_handler(event, prog_fd);
if (event->tp_event->prog)
return -EEXIST;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 460a031c77e5..18be7f53e2a6 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -235,6 +235,8 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
u64 index = flags & BPF_F_INDEX_MASK;
struct bpf_event_entry *ee;
struct perf_event *event;
+ u64 value = 0;
+ int err;
if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
return -EINVAL;
@@ -247,21 +249,14 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
if (!ee)
return -ENOENT;
- event = ee->event;
- if (unlikely(event->attr.type != PERF_TYPE_HARDWARE &&
- event->attr.type != PERF_TYPE_RAW))
- return -EINVAL;
-
- /* make sure event is local and doesn't have pmu::count */
- if (unlikely(event->oncpu != cpu || event->pmu->count))
- return -EINVAL;
-
+ err = perf_event_read_local(ee->event, &value);
/*
- * we don't know if the function is run successfully by the
- * return value. It can be judged in other places, such as
- * eBPF programs.
+ * this api is ugly since we miss [-22..-2] range of valid
+ * counter values, but that's uapi
*/
- return perf_event_read_local(event);
+ if (err)
+ return err;
+ return value;
}
static const struct bpf_func_proto bpf_perf_event_read_proto = {
--
2.9.3
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