Merge tag 'perf-urgent-2020-04-05' of git://git.kernel.org/pub/scm/linux/kernel/git...

[platform/kernel/linux-starfive.git] / kernel / events / core.c

diff --git a/kernel/events/core.c b/kernel/events/core.c
index e1459df..81e6d80 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -387,6 +387,7 @@ static atomic_t nr_freq_events __read_mostly;
 static atomic_t nr_switch_events __read_mostly;
 static atomic_t nr_ksymbol_events __read_mostly;
 static atomic_t nr_bpf_events __read_mostly;
+static atomic_t nr_cgroup_events __read_mostly;
 
 static LIST_HEAD(pmus);
 static DEFINE_MUTEX(pmus_lock);
@@ -1861,6 +1862,9 @@ static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
        if (sample_type & PERF_SAMPLE_PHYS_ADDR)
                size += sizeof(data->phys_addr);
 
+       if (sample_type & PERF_SAMPLE_CGROUP)
+               size += sizeof(data->cgroup);
+
        event->header_size = size;
 }
 
@@ -4608,6 +4612,8 @@ static void unaccount_event(struct perf_event *event)
                atomic_dec(&nr_comm_events);
        if (event->attr.namespaces)
                atomic_dec(&nr_namespaces_events);
+       if (event->attr.cgroup)
+               atomic_dec(&nr_cgroup_events);
        if (event->attr.task)
                atomic_dec(&nr_task_events);
        if (event->attr.freq)
@@ -6864,6 +6870,9 @@ void perf_output_sample(struct perf_output_handle *handle,
        if (sample_type & PERF_SAMPLE_PHYS_ADDR)
                perf_output_put(handle, data->phys_addr);
 
+       if (sample_type & PERF_SAMPLE_CGROUP)
+               perf_output_put(handle, data->cgroup);
+
        if (sample_type & PERF_SAMPLE_AUX) {
                perf_output_put(handle, data->aux_size);
 
@@ -7063,6 +7072,16 @@ void perf_prepare_sample(struct perf_event_header *header,
        if (sample_type & PERF_SAMPLE_PHYS_ADDR)
                data->phys_addr = perf_virt_to_phys(data->addr);
 
+#ifdef CONFIG_CGROUP_PERF
+       if (sample_type & PERF_SAMPLE_CGROUP) {
+               struct cgroup *cgrp;
+
+               /* protected by RCU */
+               cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
+               data->cgroup = cgroup_id(cgrp);
+       }
+#endif
+
        if (sample_type & PERF_SAMPLE_AUX) {
                u64 size;
 
@@ -7736,6 +7755,105 @@ void perf_event_namespaces(struct task_struct *task)
 }
 
 /*
+ * cgroup tracking
+ */
+#ifdef CONFIG_CGROUP_PERF
+
+struct perf_cgroup_event {
+       char                            *path;
+       int                             path_size;
+       struct {
+               struct perf_event_header        header;
+               u64                             id;
+               char                            path[];
+       } event_id;
+};
+
+static int perf_event_cgroup_match(struct perf_event *event)
+{
+       return event->attr.cgroup;
+}
+
+static void perf_event_cgroup_output(struct perf_event *event, void *data)
+{
+       struct perf_cgroup_event *cgroup_event = data;
+       struct perf_output_handle handle;
+       struct perf_sample_data sample;
+       u16 header_size = cgroup_event->event_id.header.size;
+       int ret;
+
+       if (!perf_event_cgroup_match(event))
+               return;
+
+       perf_event_header__init_id(&cgroup_event->event_id.header,
+                                  &sample, event);
+       ret = perf_output_begin(&handle, event,
+                               cgroup_event->event_id.header.size);
+       if (ret)
+               goto out;
+
+       perf_output_put(&handle, cgroup_event->event_id);
+       __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
+
+       perf_event__output_id_sample(event, &handle, &sample);
+
+       perf_output_end(&handle);
+out:
+       cgroup_event->event_id.header.size = header_size;
+}
+
+static void perf_event_cgroup(struct cgroup *cgrp)
+{
+       struct perf_cgroup_event cgroup_event;
+       char path_enomem[16] = "//enomem";
+       char *pathname;
+       size_t size;
+
+       if (!atomic_read(&nr_cgroup_events))
+               return;
+
+       cgroup_event = (struct perf_cgroup_event){
+               .event_id  = {
+                       .header = {
+                               .type = PERF_RECORD_CGROUP,
+                               .misc = 0,
+                               .size = sizeof(cgroup_event.event_id),
+                       },
+                       .id = cgroup_id(cgrp),
+               },
+       };
+
+       pathname = kmalloc(PATH_MAX, GFP_KERNEL);
+       if (pathname == NULL) {
+               cgroup_event.path = path_enomem;
+       } else {
+               /* just to be sure to have enough space for alignment */
+               cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
+               cgroup_event.path = pathname;
+       }
+
+       /*
+        * Since our buffer works in 8 byte units we need to align our string
+        * size to a multiple of 8. However, we must guarantee the tail end is
+        * zero'd out to avoid leaking random bits to userspace.
+        */
+       size = strlen(cgroup_event.path) + 1;
+       while (!IS_ALIGNED(size, sizeof(u64)))
+               cgroup_event.path[size++] = '\0';
+
+       cgroup_event.event_id.header.size += size;
+       cgroup_event.path_size = size;
+
+       perf_iterate_sb(perf_event_cgroup_output,
+                       &cgroup_event,
+                       NULL);
+
+       kfree(pathname);
+}
+
+#endif
+
+/*
  * mmap tracking
  */
 
@@ -10778,6 +10896,8 @@ static void account_event(struct perf_event *event)
                atomic_inc(&nr_comm_events);
        if (event->attr.namespaces)
                atomic_inc(&nr_namespaces_events);
+       if (event->attr.cgroup)
+               atomic_inc(&nr_cgroup_events);
        if (event->attr.task)
                atomic_inc(&nr_task_events);
        if (event->attr.freq)
@@ -11157,6 +11277,12 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
 
        if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
                ret = perf_reg_validate(attr->sample_regs_intr);
+
+#ifndef CONFIG_CGROUP_PERF
+       if (attr->sample_type & PERF_SAMPLE_CGROUP)
+               return -EINVAL;
+#endif
+
 out:
        return ret;
 
@@ -12754,6 +12880,12 @@ static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
        kfree(jc);
 }
 
+static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
+{
+       perf_event_cgroup(css->cgroup);
+       return 0;
+}
+
 static int __perf_cgroup_move(void *info)
 {
        struct task_struct *task = info;
@@ -12775,6 +12907,7 @@ static void perf_cgroup_attach(struct cgroup_taskset *tset)
 struct cgroup_subsys perf_event_cgrp_subsys = {
        .css_alloc      = perf_cgroup_css_alloc,
        .css_free       = perf_cgroup_css_free,
+       .css_online     = perf_cgroup_css_online,
        .attach         = perf_cgroup_attach,
        /*
         * Implicitly enable on dfl hierarchy so that perf events can