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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@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Alexei Starovoitov 2017-06-02 21:03:52 -07:00 committed by David S. Miller
parent 5071034e4a
commit f91840a32d
4 changed files with 48 additions and 56 deletions
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7
include/linux/perf_event.h
View File

@ -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; }

28
kernel/bpf/arraymap.c
View File

@ -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;

47
kernel/events/core.c
View File

@ -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;

22
kernel/trace/bpf_trace.c
View File

@ -234,7 +234,8 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
unsigned int cpu = smp_processor_id();
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 +248,14 @@ 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 = {