On 08/22/2018 03:53 AM, Song Liu wrote: > This patch applies on top of Ravi Bangoria's work that enables reference > count for uprobe: > > https://lkml.org/lkml/2018/8/20/37 > > After Ravi's work, the effort to enable it in fd-based uprobe is straight > forward. Highest 40 bits of perf_event_attr.config is used to stored offset > of the reference count (semaphore). > > Format information in /sys/bus/event_source/devices/uprobe/format/ is > updated to reflect this new feature. LGTM Reviewed-and-tested-by: Ravi Bangoria <ravi.bango...@linux.ibm.com> > > Signed-off-by: Song Liu <songliubrav...@fb.com> > Cc: Ravi Bangoria <ravi.bango...@linux.ibm.com> > Cc: Masami Hiramatsu <mhira...@kernel.org> > Cc: Oleg Nesterov <o...@redhat.com> > Cc: Srikar Dronamraju <sri...@linux.vnet.ibm.com> > Cc: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com> > Cc: Steven Rostedt (VMware) <rost...@goodmis.org> > Cc: Peter Zijlstra <pet...@infradead.org> > Cc: Ingo Molnar <mi...@redhat.com> > Cc: Teng Qin <qint...@fb.com> > --- > include/linux/trace_events.h | 3 +- > kernel/events/core.c | 49 ++++++++++++++++++++++++++------- > kernel/trace/trace_event_perf.c | 7 +++-- > kernel/trace/trace_probe.h | 3 +- > kernel/trace/trace_uprobe.c | 4 ++- > 5 files changed, 50 insertions(+), 16 deletions(-) > > diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h > index 78a010e19ed4..4130a5497d40 100644 > --- a/include/linux/trace_events.h > +++ b/include/linux/trace_events.h > @@ -575,7 +575,8 @@ extern int bpf_get_kprobe_info(const struct perf_event > *event, > bool perf_type_tracepoint); > #endif > #ifdef CONFIG_UPROBE_EVENTS > -extern int perf_uprobe_init(struct perf_event *event, bool is_retprobe); > +extern int perf_uprobe_init(struct perf_event *event, > + unsigned long ref_ctr_offset, bool is_retprobe); > extern void perf_uprobe_destroy(struct perf_event *event); > extern int bpf_get_uprobe_info(const struct perf_event *event, > u32 *fd_type, const char **filename, > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 8f0434a9951a..75a0219be420 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -8363,30 +8363,39 @@ static struct pmu perf_tracepoint = { > * > * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe > * if not set, create kprobe/uprobe > + * > + * The following values specify a reference counter (or semaphore in the > + * terminology of tools like dtrace, systemtap, etc.) Userspace Statically > + * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset. > + * > + * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset > + * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left > */ > enum perf_probe_config { > PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */ > + PERF_UPROBE_REF_CTR_OFFSET_BITS = 40, > + PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS, > }; > > PMU_FORMAT_ATTR(retprobe, "config:0"); > +#endif > > -static struct attribute *probe_attrs[] = { > +#ifdef CONFIG_KPROBE_EVENTS > +static struct attribute *kprobe_attrs[] = { > &format_attr_retprobe.attr, > NULL, > }; > > -static struct attribute_group probe_format_group = { > +static struct attribute_group kprobe_format_group = { > .name = "format", > - .attrs = probe_attrs, > + .attrs = kprobe_attrs, > }; > > -static const struct attribute_group *probe_attr_groups[] = { > - &probe_format_group, > +static const struct attribute_group *kprobe_attr_groups[] = { > + &kprobe_format_group, > NULL, > }; > -#endif > > -#ifdef CONFIG_KPROBE_EVENTS > static int perf_kprobe_event_init(struct perf_event *event); > static struct pmu perf_kprobe = { > .task_ctx_nr = perf_sw_context, > @@ -8396,7 +8405,7 @@ static struct pmu perf_kprobe = { > .start = perf_swevent_start, > .stop = perf_swevent_stop, > .read = perf_swevent_read, > - .attr_groups = probe_attr_groups, > + .attr_groups = kprobe_attr_groups, > }; > > static int perf_kprobe_event_init(struct perf_event *event) > @@ -8428,6 +8437,24 @@ static int perf_kprobe_event_init(struct perf_event > *event) > #endif /* CONFIG_KPROBE_EVENTS */ > > #ifdef CONFIG_UPROBE_EVENTS > +PMU_FORMAT_ATTR(ref_ctr_offset, "config:63-24"); > + > +static struct attribute *uprobe_attrs[] = { > + &format_attr_retprobe.attr, > + &format_attr_ref_ctr_offset.attr, > + NULL, > +}; > + > +static struct attribute_group uprobe_format_group = { > + .name = "format", > + .attrs = uprobe_attrs, > +}; > + > +static const struct attribute_group *uprobe_attr_groups[] = { > + &uprobe_format_group, > + NULL, > +}; > + > static int perf_uprobe_event_init(struct perf_event *event); > static struct pmu perf_uprobe = { > .task_ctx_nr = perf_sw_context, > @@ -8437,12 +8464,13 @@ static struct pmu perf_uprobe = { > .start = perf_swevent_start, > .stop = perf_swevent_stop, > .read = perf_swevent_read, > - .attr_groups = probe_attr_groups, > + .attr_groups = uprobe_attr_groups, > }; > > static int perf_uprobe_event_init(struct perf_event *event) > { > int err; > + unsigned long ref_ctr_offset; > bool is_retprobe; > > if (event->attr.type != perf_uprobe.type) > @@ -8458,7 +8486,8 @@ static int perf_uprobe_event_init(struct perf_event > *event) > return -EOPNOTSUPP; > > is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; > - err = perf_uprobe_init(event, is_retprobe); > + ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT; > + err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe); > if (err) > return err; > > diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c > index 69a3fe926e8c..76217bbef815 100644 > --- a/kernel/trace/trace_event_perf.c > +++ b/kernel/trace/trace_event_perf.c > @@ -290,7 +290,8 @@ void perf_kprobe_destroy(struct perf_event *p_event) > #endif /* CONFIG_KPROBE_EVENTS */ > > #ifdef CONFIG_UPROBE_EVENTS > -int perf_uprobe_init(struct perf_event *p_event, bool is_retprobe) > +int perf_uprobe_init(struct perf_event *p_event, > + unsigned long ref_ctr_offset, bool is_retprobe) > { > int ret; > char *path = NULL; > @@ -312,8 +313,8 @@ int perf_uprobe_init(struct perf_event *p_event, bool > is_retprobe) > goto out; > } > > - tp_event = create_local_trace_uprobe( > - path, p_event->attr.probe_offset, is_retprobe); > + tp_event = create_local_trace_uprobe(path, p_event->attr.probe_offset, > + ref_ctr_offset, is_retprobe); > if (IS_ERR(tp_event)) { > ret = PTR_ERR(tp_event); > goto out; > diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h > index 5f52668e165d..03b10f3201a5 100644 > --- a/kernel/trace/trace_probe.h > +++ b/kernel/trace/trace_probe.h > @@ -412,6 +412,7 @@ create_local_trace_kprobe(char *func, void *addr, > unsigned long offs, > extern void destroy_local_trace_kprobe(struct trace_event_call *event_call); > > extern struct trace_event_call * > -create_local_trace_uprobe(char *name, unsigned long offs, bool is_return); > +create_local_trace_uprobe(char *name, unsigned long offs, > + unsigned long ref_ctr_offset, bool is_return); > extern void destroy_local_trace_uprobe(struct trace_event_call *event_call); > #endif > diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c > index 3a7c73c40007..d09638706fe0 100644 > --- a/kernel/trace/trace_uprobe.c > +++ b/kernel/trace/trace_uprobe.c > @@ -1405,7 +1405,8 @@ static int unregister_uprobe_event(struct trace_uprobe > *tu) > > #ifdef CONFIG_PERF_EVENTS > struct trace_event_call * > -create_local_trace_uprobe(char *name, unsigned long offs, bool is_return) > +create_local_trace_uprobe(char *name, unsigned long offs, > + unsigned long ref_ctr_offset, bool is_return) > { > struct trace_uprobe *tu; > struct path path; > @@ -1437,6 +1438,7 @@ create_local_trace_uprobe(char *name, unsigned long > offs, bool is_return) > > tu->offset = offs; > tu->path = path; > + tu->ref_ctr_offset = ref_ctr_offset; > tu->filename = kstrdup(name, GFP_KERNEL); > init_trace_event_call(tu, &tu->tp.call); > >
